| 6660332 | Methods and apparatus for making color filter by discharging a filter material | December, 2003 | Kawase et al. | |
| 6715852 | Liquid jetting apparatus | April, 2004 | Yonekubo | 347/10 |
| 20020105688 | Apparatus and method for producing color filters by discharging material | August, 2002 | Katagami et al. | |
| 20040051817 | Display manufacturing apparatus and display manufacturing method | March, 2004 | Takahashi et al. | 349/1 |
| 20040081768 | Method of manufacturing a device, device, and electronic apparatus | April, 2004 | Furusawa et al. | 427/421 |
| JP2002148422 | May, 2002 | FILTER, METHOD FOR MANUFACTURING THE SAME, AND OPTOELECTRONIC DEVICE USING THE SAME | ||
| JP2002221616 | August, 2002 | METHOD AND DEVICE FOR MANUFACTURING COLOR FILTER, METHOD AND DEVICE FOR MANUFACTURING LIQUID CRYSTAL DEVICE, METHOD AND DEVICE FOR MANUFACTURING EL DEVICE, DEVICE FOR CONTROLLING INKJET HEAD, METHOD AND DEVICE FOR DISCHARGING MATERIAL AND ELECTRONIC INSTRUMENT | ||
| JP2002273868 | September, 2002 | DEVICE AND METHOD FOR DISCHARGING MATERIAL, APPARATUS AND METHOD FOR MANUFACTURING COLOR FILTER, APPARATUS AND METHOD FOR MANUFACTURING LIQUID CRYSTAL DEVICE, APPARATUS AND METHOD FOR MANUFACTURING EL DEVICE, AND ELECTRONIC DEVICE TO BE MANUFACTURED BY THE METHODS |
1. A film-forming method for forming a planar periodic structure having a predetermined periodicity by depositing liquid material on an object, the method comprising: providing liquid drop supplying means capable of supplying a liquid drop at a predetermined driving period to deposit the liquid material on the object; controlling the presence or absence of the supply of the liquid drop by the liquid drop supplying means at each driving period of the driving period in accordance with the periodicity of the planar periodic structure to be formed on the object; and supplying the liquid drop by the control of the liquid drop supplying means while the liquid drop supplying means is scanned at a predetermined scanning speed in a predetermined scanning direction relative to the object; wherein a natural number times a value obtained by multiplying the driving period and the scanning speed is set to be the structural period of the planar periodic structure, to be formed on the object, in the scanning direction.
2. The film-forming method according to claim 1, wherein a step of scanning the liquid drop supplying means relative to the object in the scanning direction is performed several times and an operation of feeding the liquid drop supplying means to the object in a direction intersecting the scanning direction is performed during intervals between scanning operations.
3. The film-forming method according to claim 1, wherein the liquid drop supplying means is provided with a nozzle row including a plurality of nozzles to supply the liquid drop, and the liquid drop supplying means is scanned relative to the object in the scanning direction in a position in which an arrangement period of the nozzles in the nozzle row as seen from a direction perpendicular to the scanning direction is set to correspond to a structural period as seen from a direction perpendicular to the scanning direction of the planar periodic structure to be formed.
4. The film-forming method according to claim 3, wherein a difference between: a phase difference between a periodicity of the planar periodic structure in the scanning direction at a predetermined position as seen from a direction perpendicular to the scanning direction and another periodicity of the planar periodic structure in the scanning direction at another position other than the predetermined position as seen from a direction perpendicular to the scanning direction; and a positional deviation as seen from the scanning direction between a predetermined nozzle corresponding to the predetermined position and another nozzle corresponding to the another position; is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed.
5. The film-forming method according to claim 3, wherein a time difference is provided between a liquid drop supplying time of a predetermined nozzle disposed at a predetermined position as seen from the direction perpendicular to the scanning direction and a liquid drop supplying time of another nozzle disposed at another position as seen from the direction perpendicular to the scanning direction; and wherein a difference between: a phase difference between a periodicity of the planar periodic structure in the scanning direction at the predetermined position and another periodicity of the planar periodic structure in the scanning direction at another position; and a value obtained by multiplying the time difference and the scanning speed; is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed.
6. A method for manufacturing a color filter substrate comprising: a film-forming step in which liquid material is supplied onto a substrate to film-form a plurality of filter elements in a planar periodic pattern having a predetermined periodicity; wherein, in the film-forming process, liquid drop supplying means is used which is capable of supplying a liquid drop at a predetermined driving period to deposit the liquid material on the object; the presence or absence of the supply of the liquid drop by the liquid drop supplying means is controlled at each driving period of the driving period in accordance with the periodicity of the planar periodic pattern to be formed on the object; and the liquid drop is supplied by the control of the liquid drop supplying means while the liquid drop supplying means is scanned at a predetermined scanning speed in a predetermined scanning direction relative to the object; and wherein a natural number times a value obtained by multiplying the driving period and the scanning speed is set to be the structural period of the planar periodic pattern, to be formed, in the scanning direction.
7. The method for manufacturing a color filter according to claim 6, wherein a step of scanning the liquid drop supplying means relative to the object in the scanning direction is performed several times and an operation of feeding the liquid drop supplying means to the object in a direction intersecting the scanning direction is performed during intervals between scanning operations.
8. The method for manufacturing a color filter substrate according to claim 6, wherein the liquid drop supplying means is provided with a nozzle row including a plurality of nozzles to supply the liquid drop, and the liquid drop supplying means is scanned relative to the object in the scanning direction in the position in which an arrangement period of the nozzles at the nozzle row as seen from a direction perpendicular to the scanning direction is set to correspond to a structural period as seen from a direction perpendicular to the scanning direction of the planar periodic pattern to be formed.
9. The method for manufacturing a color filter substrate according to claim 8, wherein a difference between: a phase difference between a periodicity of the planar periodic pattern in the scanning direction at a predetermined position as seen from a direction perpendicular to the scanning direction and another periodicity of the planar periodic pattern in the scanning direction at another position other than the predetermined position as seen from a direction perpendicular to the scanning direction; and a positional deviation as seen from the scanning direction between a predetermined nozzle corresponding to the predetermined position and another nozzle corresponding to the another position; is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed, thereby forming a film.
10. The method for manufacturing a color filter substrate according to claim 8, wherein a time difference is provided between a liquid drop supplying time of a predetermined nozzle disposed at a predetermined position as seen from the direction perpendicular to the scanning direction and a liquid drop supplying time of another nozzle disposed at another position other than the predetermined position as seen from the direction perpendicular to the scanning direction; and wherein a difference between: a phase difference between a periodicity of the planar periodic pattern in the scanning direction at the predetermined position and another periodicity of the planar periodic pattern in the scanning direction at the another position; and a value obtained by multiplying the time difference and the scanning speed; is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed, thereby forming a film.
11. The method for manufacturing a color filter substrate according to claim 6, wherein the planar periodic pattern is obtained by arranging a plurality of colors of the filter elements in a planar periodic pattern, and the film-forming process is performed to at least one of the plurality of colors of the filter elements.
12. The method for manufacturing a color filter substrate according to claim 11, wherein the film-forming process is performed to a blue color filter element of the filter elements.
13. A method for manufacturing a substrate for an electroluminescent device comprising: a film-forming step in which the liquid material is supplied onto the substrate to film-form a plurality of pixel regions in a planar periodic pattern having a predetermined periodicity; wherein, in the film-forming process: liquid drop supplying means is used which is capable of supplying a liquid drop at a predetermined driving period to deposit the liquid material on the object; the presence or absence of the supply of the liquid drop by the liquid drop supplying means is controlled at each driving period in accordance with the periodicity of the planar periodic pattern to be formed on the object; and the liquid drop is supplied by the control of the liquid drop supplying means while the liquid drop supplying means is scanned at a predetermined scanning speed in a predetermined scanning direction relative to the object; and wherein a natural number times a value obtained by multiplying the driving period and the scanning speed is set to be the structural period of the planar periodic pattern, to be formed on the object, in the scanning direction.
14. The method for manufacturing a substrate for an electroluminescent device according to claim 13, wherein a step of scanning the liquid drop supplying means relative to the object in the scanning direction is performed several times and an operation of feeding the liquid drop supplying means to the object in a direction intersecting the scanning direction is performed during intervals between scanning operations.
15. The method for manufacturing a substrate for an electroluminescent device according to claim 13, wherein the liquid drop supplying means is provided with a nozzle row including a plurality of nozzles to supply the liquid drop, and the liquid drop supplying means is scanned relative to the object in the scanning direction in the position in which an arrangement period of the nozzles at the nozzle row as seen from a direction perpendicular to the scanning direction is set to correspond to a structural period as seen from a direction perpendicular to the scanning direction of the planar periodic pattern to be formed.
16. The method for manufacturing a substrate for an electroluminescent device according to claim 15, wherein a difference between: a phase difference between a periodicity of the planar periodic pattern, to be formed on the object, in the scanning direction, at a predetermined position as seen from a direction perpendicular to the scanning direction and another periodicity of the planar periodic pattern in the scanning direction at another position other than the predetermined position as seen from a direction perpendicular to the scanning direction; and a positional deviation as seen from the scanning direction between a predetermined nozzle corresponding to the predetermined position and another nozzle corresponding to the another position; is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed, thereby forming a film.
17. The method for manufacturing a substrate for an electroluminescent device according to claim 15, wherein a time difference is provided between a liquid drop supplying time of a predetermined nozzle disposed at a predetermined position as seen from the direction perpendicular to the scanning direction and a liquid drop supplying time of another nozzle disposed at another position other than the predetermined position as seen from the direction perpendicular to the scanning direction; and wherein a difference between: a phase difference between a periodicity of the planar periodic pattern in the scanning direction at the predetermined position and another periodicity of the planar periodic pattern in the scanning direction at the another position; and a value obtained by multiplying the time difference and the scanning speed; is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed, thereby forming a film.
18. The method for manufacturing a substrate for an electroluminescent device according to claim 13, wherein the planar periodic pattern is obtained by arranging a plurality of colors of the pixel regions in a predetermined arrangement pattern, and the film-forming process is performed to at least one of the plurality of colors of the pixel regions.
19. The method for manufacturing a substrate for an electroluminescent device according to claim 18, wherein the film-forming process is performed to a blue color pixel region.
20. A method for manufacturing a display device comprising: forming a plurality of pixels arranged at the planar periodic period using a film-forming method according to claim 1.
21. A method for manufacturing a display device comprising: forming a color filter substrate using a manufacturing method according to claim 6.
22. A method for manufacturing a display device comprising: forming a substrate for an electroluminescent device using a manufacturing method according to claim 13.
RELATED APPLICATIONS
This application claims priority to Japanese Patent Application No. 2003-060253 filed Mar. 6, 2003 which is hereby expressly incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a film-forming method, a film-forming apparatus, an apparatus and a method for manufacturing a color filter substrate, an apparatus and a method for manufacturing a substrate for an electroluminescent device, a method for manufacturing a display device, a display device, and an electronic apparatus. More specifically, the present invention relates to a manufacturing technique for forming a film by supplying liquid material in a liquid drop state.
2. Description of the Related Art
In general, there are known a variety of display devices using as a display means an electro-optical apparatus such as a liquid crystal display device or an electroluminescent device (hereinafter, referred to as EL device), or an electronic apparatus, such as a cellular phone and a portable information terminal, in which such display device is built. As the color display has been in general use, such a display device commonly utilizes color filters formed in a predetermined arrangement patterns such as a stripe pattern, delta pattern, or mosaic pattern that consists of filter elements on red (R), green (G) and blue (B) dots on the surface of a substrate made of glass, plastic or the like.
Besides, in the EL device allowing color display, the red (R), green (G), and blue (B) dots of an EL light-emitting layer are arranged on the surface of a substrate made of glass, plastic or the like in a predetermined arrangement pattern such as stripe pattern, delta pattern or mosaic pattern, and such EL light-emitting layer is disposed between a pair of electrodes to thereby form a display dot. Then, a voltage applied to these electrodes is controlled for each display dot, so that each display dot emits light in a predetermined color and grayscale.
When manufacturing a variety of display devices as described above, photolithography is generally used for patterning respective colors of filter filaments of the color filter or respective colors of light-emitting layers of the EL device. However, the patterning process using photolithography requires several complicated, time-consuming processes such as coating, exposure and development of materials, and a large quantity of respective color materials or resists are consumed which leads to a problem of high costs.
In order to solve the aforementioned problem, a method for forming filter filaments or light-emitting layers arranged in a dot shape by adding solvent to filter element materials or EL light emitting materials to make a liquid material and discharging the liquid material as a liquid drop to be deposited to the surface of a substrate using an ink jet method, has been suggested. Here, according to the ink jet method, a case for forming filter elements 303 arranged in a dot shape, as shown in FIG. 29(b), inside a plurality of unit regions 302 set at the surface of a mother substrate 301, i.e., a large area of a substrate made of glass or plastic, as shown in FIG. 29(a), will be described.
In that case, for example, a liquid supplying head 306 having a nozzle row 305 of a plurality of nozzles 304, as shown in FIG. 29(c), is scanned along a straight line several times (twice in FIG. 29(b)) relative to a single unit region 302, as indicated by arrows A1 and A2 in FIG. 29(b). During each scanning period of time, ink or filter material is selectively discharged from a plurality of nozzles 304, thereby forming a filter element 303 at a desired position.
As described above, the filter elements 303 are arranged in a stripe pattern, delta pattern or mosaic pattern of respective colors, red (R), green (G), and blue (B). Therefore, in general, colors of red (R), green (G), and blue (B) are respectively prepared and respective liquid drop supplying heads 306 are utilized in sequence, thereby forming a color filter having a predetermined color arrangement on a mother substrate 301.
On the other hand, with regard to the liquid drop supplying heads 306, since there is a difference in the amount of ink depending upon a plurality of nozzles 304 consisting of a nozzle row 305, there may be a stripe pattern irregularity due to the difference of ink at respective filter elements 303 when the filter elements 303 are formed by the liquid drop supplying head 306 as shown in FIG. 29(b). As a result, there is a problem that the light transmissivity to a plane of a color filter is not uniform. Accordingly, there has been a method (for example, refer to Japanese Unexamined Patent Application Publication No. 2002-221616) in which respective filter elements are formed by discharging a plurality of liquid drops and the liquid drops are scanned in sequence as the position of the liquid drop supplying head 306 is moved little by little in the direction of sending liquid drops (the left and right directions in FIG. 29).
However, if a scanning process is performed in the aforementioned way, the number of scanning processes is rapidly increasing which makes the manufacturing time longer, thereby resulting in a problem of lowering production efficiency. Thus, in order to solve the aforementioned problem, an apparatus is suggested with a plurality of heads capable of adjusting of their positions mounted to a common carriage to widen its one-time scanning scope for an efficient manufacturing process (for example, refer to Japanese Unexamined Patent Application Publication No. 2002-273868).
However, the inventor found that it is impossible to eliminate a stripe pattern color irregularity in spite of the minimization of a difference in the amount of ink among respective filter elements in the aforementioned method if the color filter is manufactured in the conventional apparatus. As a result of continuous experiments, it has been found that the stripe pattern color irregularity is caused not by a difference in the amount of ink, but by a charge status of ink in respective filter elements. In other words, the deviated state of ink charged in the respective filter elements results in a difference in the amount of transmissive light depending upon places, which makes a stripe pattern of color irregularity noticeable.
FIG. 34 illustrates optical characteristics of a color filter manufactured in the conventional method. At this time, in FIG. 34(A), the vertical axis indicates Y value of transmissive light of the color filter (CIE1931XYZ color coordinate system, or brightness Y in the YUV color base), and the horizontal axis indicates periodic deviation characteristics of brightness Y seen in the scanning direction when the pixel array of the scanning direction (vertical direction as illustrated therein) illustrated in FIG. 29(b). Besides, as described above, FIG. 34(B) indicates periodic deviation characteristics as seen from the sending direction (horizontal direction as illustrated therein) illustrated in FIG. 29(b). Such deviation characteristics of brightness Y are not caused by a difference in the amount of ink due to the discharge characteristics of the head, but occurs even when a color filter is formed using a single nozzle.
Therefore, in the present invention, in order to solve the aforementioned problems, there is provided a technique to minimize the problem of irregularity in film formation which has not been solved by equalizing the amount of the liquid material to be supplied when a film-forming method is performed by depositing the liquid material on an object with a liquid drop supply means such as a liquid drop supply head.
SUMMARY
After several strenuous investigations, the inventor has reached a conclusion that the stripe pattern irregularity in film formation is caused by an unequal supply of the liquid material inside the regions where the liquid material is filled due to differences in the supply position (depositing position) of a liquid drop in spite of an equal amount of the liquid material to be included in the liquid drop.
For example, when a plurality of liquid drops Q are supplied into a specific region P to deposit a liquid material U, two different cases are compared. As shown in FIG. 30, A-1 illustrates one case that almost all of the first liquid drop Q1 is supplied to almost the center of region P to thereby deposit a liquid material U1 at almost the center of region P, and B-1 illustrates the other case that the first liquid drop Q1′ is supplied to the periphery of region P to thereby deposit the liquid material U1′ at the periphery of region P.
In the first case (A-1) the first liquid material U1 is deposited at the center of region P, so that following liquid drop Q2 is integrated with the liquid material U1 already deposited at the center of the region P even if the following liquid drop Q2 is supplied to a position diverted from the center of region P. Therefore, a liquid material U2 relating to liquid drops Q1, Q2 is also arranged almost at the center of region P as illustrated in A-2. At this time, as shown in A-3 and A-4, even if liquid drops Q3, Q4 are supplied in sequence, liquid materials U3, U4 can be easily and uniformly deposited. If the liquid material is equally deposited within region P, a liquid material U4 is dried at last to result in an almost equally formed film as indicated with a long dot line in A-4.
On the other hand, in case of B-1, since the initial liquid material U1 is deposited at the periphery of region P, the following Q2′ is integrated with the liquid material U1 that has already deposited at the periphery of region P. Therefore, as shown in B-2, the liquid material U2′ relating to two liquid drops Q1′, Q2′ is also deposited at the periphery of region P. At this time, as illustrated in B-3 and B-4, liquid materials U3′, U4′ relating to the sequential supply of liquid drops Q3′, Q4′ tilt to the periphery of region P. In an extreme case, the liquid material is partially flooded over region P, and the liquid material may be deposited at other regions adjacent to region P to become liquid materials U3″, U4″. If the liquid material U4′ that has been deposited at the neighboring regions is dried, an inclined film is formed as shown with a long dot line in B-4.
As described above, since the state of the finally formed film is different depending on the position of an initially supplied liquid drop, there may be a difference in the stripe pattern irregularity in film formation. The stripe pattern of the irregularity in film formation is not limited to the case that a plurality of liquid drops are supplied to region P. As shown in FIG. 30, the difference is also apparent when a single liquid drop is supplied to region P. If the same amount of the liquid material is supplied as a single liquid drop, a difference is made in the finally formed films shown in A-4 and B-4 of FIG. 30 depending upon the supplying position of the liquid drop. In any case, the state of the finally formed film is greatly changed by a supplying position of a liquid drop, the stripe pattern irregularity in film formation (color or brightness irregularity in case of a display device) will appear even when the amount of the liquid material included in the liquid drop is equalized. Further, as shown in B-3 and B-4 of FIG. 30, the liquid materials U3″ and U4″ flooded out of region P result in a cause of mixed colors and an increase of irregularity in case of a color filter or an EL device for example.
As shown in FIG. 31, the region P is partitioned with a partition wall or a bank B (hereinafter, referred to as ‘partition wall’) and a liquid drop is supplied into the region P surrounded with the partition wall B. For example, the partition wall B is constructed of a synthetic resin that has been patterned on a substrate by a photolithographic method or the like.
At this time, the external appearance of the liquid material U is changed by presence of the partition wall B depending upon the supplying position of the liquid drop Q. For example, as shown in FIG. 31(a) or (b), if liquid drops Qa, Qb are supplied to the center of the region P, a position relatively close to the center thereof or a position a little far from the partition wall B, the appearance of liquid materials Ua, Ub provided inside the region P is not affected by the presence of the partition wall B. However, as shown in FIG. 31(c), if the liquid drop Qc is supplied to a position close to the partition wall B, a periphery of region P, a liquid material Uc contacts partition wall B at the time of depositing and enlarging and moves along the partition wall B like being sucked in. As a result, the liquid material Uc is shaped according to the wall surface of the partition wall B as shown. At this time, it becomes difficult to stop unequal deposition of the liquid material in the region P even though the liquid drop is additionally supplied.
Next, the inventor has checked the conventional liquid drop supplying state. The liquid drop supplying means such as a liquid supplying head or the like is generally driven at a predetermined driving period Td (the driving frequency of a driving signal Fd=1/Td). When scanning speed Vx is applied with the small driving period Td, resolution of supplying position of the liquid drop Rx=Td×Vx is small and it is possible to more correctly set up the supplying position of the liquid drop. For example, FIG. 32 illustrates a case that the liquid drop is supplied at a predetermined driving period Td while the liquid drop supplying means scans an object periodically arranged with a plurality of regions P at a constant level of scanning speed Vx. FIGS. 32(a) to (c) illustrate respective cases that the liquid drop is supplied to three different resolutions of R1<R2<R3 for comparison. When the driving period Td is large, the supplying position of the liquid drop in region P can be controlled not in precision, but as shown in (c), turns out to be more irregular at a plurality of regions P arranged in the scanning direction. In contrast, if the driving period Td is small, as shown in (a), the supplying position of the liquid drop is precisely set inside region P, and it is possible to reduce the irregularity of the supplying position of the liquid drop among regions P. Therefore, as described above, the liquid drop can be supplied to a proper position inside the region, thereby making it possible to restrict the stripe pattern irregularity in film formation.
However, in actuality, if the driving period Td of the liquid drop supplying means is small, the supply of the liquid material is not sufficient for the liquid drop supplying means. In other words, the amount of the liquid material included in the one liquid drop gets smaller not to stabilize the liquid material to be introduced to the liquid drop supplying means, so that it is easy to cause a defect in the liquid drop discharging shape of a so-called flight curve or satellite. Therefore, there is a limitation to an increase in the driving frequency of the liquid drop supplying means.
Accordingly, if the driving period Td is small, a deviation in the supplying positions of the liquid drop among regions P decreases to restrict irregularity in film formation, but there are problems that productivity decreases and that film-forming defects increase. In other words, if the scanning is carried out in the direction of x as shown in FIG. 33, and if resolution Rx is large, the difference of the supplying position of the liquid drop among respective regions P arranged in the scanning direction X is large with generation of the irregularity in film formation. At this time, the structural period of region P as seen from the scanning direction X is regarded as Dx, and driving period Td multiplied with scanning speed Vx is regarded as resolution Rx. On the contrary, if resolution Rx is small, the difference in the supplying position of the liquid drop among regions P as seen from the scanning direction X is small, but the manufacturing efficiency decreases and resultant defects easily occur because the supplying amount of the liquid material as the liquid drop decreases.
Thus, as a result of having investigated repeatedly and zealously based on the situation, the present inventors have reached the invention shown below. In other words, the present invention provides a film-forming method for forming a planar periodic structure having a predetermined periodicity by depositing the liquid material on an object. In the film-forming method, a liquid drop supplying means is used which is constructed to be capable of supplying a liquid drop at a predetermined driving period to deposit the liquid material on the object; the presence or absence of the supply of the liquid drop by the liquid drop supplying means is controlled at each driving period of the driving period in accordance with the periodicity of the planar periodic structure to be formed on the object; and the liquid drop is supplied by the control of the liquid drop supplying means while the liquid drop supplying means is scanned at a predetermined scanning speed in a predetermined scanning direction relative to the object. A natural number times a value obtained by multiplying the driving period and the scanning speed is set to be the structural period of the planar periodic structure, to be formed on the object, in the scanning direction.
According to the above invention, a film-forming process is performed in a state that a value obtained by multiplying the driving period Td of the liquid drop supplying means and the scanning speed Vx of the liquid drop supplying means, that is, a natural number times of resolution Rx of the liquid drop supply is set to be the structural period Dx in the scanning direction of the planar periodic structure to be formed on the object. Thus, it is possible to supply the liquid drop to a predetermined phase point in the structural period Dx. As a result, it is possible to reduce the occurrence of irregularity in film formation caused by irregularity in the supplying position of the liquid drop in the structural period Dx. Besides, since the liquid drop can be supplied to a predetermined phase point in the structural period Dx as described above, it is possible to avoid a situation shown in FIG. 31(c) in which the liquid drop is supplied to the vicinity of the partition wall and the deviation of the liquid material is caused, thereby resulting in an advantage of reducing the film-forming defects. Moreover, according to the aforementioned method, it is not necessary to make the driving period Td of the liquid drop supplying means vainly small. Thus, it is possible to restrict a reduction in the amount of the liquid material included in one liquid drop. As a result, it is possible to improve the productivity and to reduce the film-forming defects due to the insufficient supply of the liquid drop such as a flight curve or a satellite.
In the present invention, preferably, a step of scanning the liquid drop supplying means relative to the object in the scanning direction is performed several times and the operation of feeding the liquid drop supplying means to the object in a direction intersecting the scanning direction is performed during intervals between the scanning operations. According to this invention, the scanning step is repeated several times and the feeding operation is performed during intervals between the scanning operations, thereby making it possible to carry out the film-formation in a wide range of a plane.
In the present invention, preferably, the liquid drop supplying means is provided with a nozzle row including a plurality of nozzles to supply the liquid drop, and the liquid drop supplying means is scanned relative to the object in the scanning direction in the position in which an arrangement period of the nozzles at the nozzle row as seen from a direction perpendicular to the scanning direction is set to correspond to a structural period as seen from a direction perpendicular to the scanning direction of the planar periodic structure to be formed. According to this invention, the nozzle row including a plurality of nozzles is provided to the liquid drop supplying means, thereby making it possible to simultaneously supply liquid drops to a plurality of rows in the planar periodic structure by a single scanning step to improve productivity. Here, when the liquid drop supplying means provided with a nozzle row has a predetermined nozzle gap, in order to match the nozzle gap with the structural period of the planar periodic structure as seen from a direction intersecting the scanning direction, it is preferable to adjust an angle of inclination θ between the arrangement direction of a nozzle row and the direction perpendicular to the scanning direction.
In the present invention, preferably, a difference between a phase difference between a periodicity of the planar periodic structure in the scanning direction at a predetermined position as seen from a direction perpendicular to the scanning direction and another periodicity of the planar periodic structure in the scanning direction at another position other than the predetermined position as seen from a direction perpendicular to the scanning direction, and a positional deviation as seen from the scanning direction between a predetermined nozzle corresponding to the predetermined position and another nozzle corresponding to the another position are set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed. In general, if the angle of inclination θ between the arrangement direction of nozzle rows and a direction perpendicular to the scanning direction is not 0, the nozzle positions as seen from the scanning direction between the plurality of nozzles are different from each other and the positional deviation of the nozzle positions as seen from the scanning direction results in a deviation in the supplying positions of the liquid drop at two different positions as seen from the direction perpendicular to the scanning direction. Irrespective of a value of angle of inclination θ, there may be a phase difference in the periodicity of a planar periodic structure to be formed in the scanning direction at two different positions as seen from the direction perpendicular to the scanning direction. Therefore, a deviation in the positions of supplying the liquid drop to a planar periodic structure to be formed occurs as much as the difference between the phase difference of the periodicity of a planar periodic structure to be formed in the scanning direction at two different positions as seen from a direction perpendicular to the scanning direction and a deviation of the nozzle positions of the liquid drop supplying means.
Therefore, the aforementioned difference is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed, thereby making it possible to relieve a deviation in the positions of supplying the liquid drop at two different points as seen from the direction perpendicular to the scanning direction.
In the present invention, preferably, a time difference is provided between a liquid drop supplying time of a predetermined nozzle disposed at a predetermined position as seen from the direction perpendicular to the scanning direction and a liquid drop supplying time of another nozzle disposed at another position as seen from the direction perpendicular to the scanning direction. A difference between a phase difference between a periodicity of the planar periodic structure in the scanning direction at the predetermined position and another periodicity of the planar periodic structure in the scanning direction at another position, and a value obtained by multiplying the time difference and the scanning speed is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed. In general, if an angle of inclination θ between the arrangement direction of nozzle rows and a direction perpendicular to the scanning direction is not 0, the nozzle positions as seen from the scanning direction between the plurality of nozzles are different from each other. Thus, the positional deviation of the nozzle positions as seen from the scanning direction results in a deviation in the supplying positions of the liquid drop at two different positions as seen from the direction perpendicular to the scanning direction. Similarly to the above, even in a planar periodic structure to be formed, there may be a phase difference in the periodicity of the scanning direction at two different positions as seen from the direction perpendicular to the scanning direction. For this reason, a deviation in the positions of supplying the liquid drop to a planar periodic structure to be formed occurs as much as a difference between the phase difference and the deviation of the nozzle positions of the liquid supplying means. At this time, a time difference is provided between liquid drop supplying timings of nozzles corresponding to two different positions as seen from the direction perpendicular to the scanning direction to be adjusted, and the phase difference and values obtained by multiplying the time difference and the scanning speed is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed to thereby relieve the deviation in the supplying positions of the liquid drop at two different positions as seen from the direction perpendicular to the scanning direction.
Next, the present invention provides a film-forming apparatus for forming a planar periodic structure having a predetermined periodicity by depositing the liquid material on an object. The film-forming apparatus comprises: a liquid drop supplying means constructed to be capable of supplying a liquid drop at a predetermined driving period to deposit the liquid drop on the object; control means capable of controlling the presence or absence of the liquid drop by the liquid drop supplying means at each driving period; scanning means to scan the liquid drop supplying means relative to the object in a predetermined scanning direction; and driving period setting means to be capable of adjusting and setting the driving period.
According to the above invention, the film-forming apparatus is constructed to be capable of properly setting a driving period of the liquid drop supplying means with the driving period setting means. Thus, it is possible to improve resolution of the liquid supplying position by making the driving period small, without a reduction in driving speed by the driving means. Therefore, it is possible to improve the precision of the liquid supplying positions by an increase in the resolution of the liquid drop supplying positions without a reduction in productivity efficiency. Besides, the natural number times of the resolution is set to be a structural period of a planar periodic structure to be formed in the scanning direction. Thus, it is possible to always supply the liquid drop consistently to a predetermined phase position of a structural period to be formed. As a result, it is possible to reduce a deviation in supplying positions of the liquid drop and irregularity in film formation.
In the present invention, preferably, the scanning means performs a step of scanning the liquid drop supplying means relative to the object in the scanning direction several times and the operation of feeding the liquid drop supplying means to the object in a direction intersecting the scanning direction is performed during intervals between the scanning operations.
In the present invention, preferably, the liquid drop supplying means is constructed to have a nozzle row having a plurality of nozzles to supply the liquid drop and to be capable of adjusting an intersecting angle between an arrangement direction of the nozzles of the nozzle row and the scanning direction.
In the present invention, preferably, the liquid drop supplying means is constructed to be capable of setting a time difference between a liquid drop supplying time of a predetermined nozzle corresponding to a position as seen from the direction perpendicular to the scanning direction and another liquid drop supplying time of another nozzle corresponding to another position other than the predetermined position as seen from the direction perpendicular to the scanning direction.
Next, the present invention provides a method for manufacturing a color filter substrate, having a film-forming step in which the liquid material is supplied onto a substrate to film-form a plurality of filter elements in a planar periodic pattern having a predetermined periodicity. In the film-forming process, a liquid drop supplying means is used which is constructed to be capable of supplying a liquid drop at a predetermined driving period to deposit the liquid material on the object; the presence or absence of the supply of the liquid drop by the liquid drop supplying means is controlled at each driving period in accordance with the periodicity of the planar periodic pattern to be formed on the object; and the liquid drop is supplied by the control of the liquid drop supplying means while the liquid drop supplying means is scanned at a predetermined scanning speed in a predetermined scanning direction relative to the object. A natural number times a value obtained by multiplying the driving period and the scanning speed is set to be the structural period of the planar periodic pattern, to be formed, in the scanning direction.
In the present invention, preferably, a step of scanning the liquid drop supplying means relative to the object in the scanning direction is performed several times and the operation of feeding the liquid drop supplying means to the object in a direction intersecting the scanning direction is performed during intervals between the scanning operations.
According to the invention, preferably, the liquid drop supplying means is provided with a nozzle row including a plurality of nozzles to supply the liquid drop, and the liquid drop supplying means is scanned relative to the object in the scanning direction in the position in which an arrangement period of the nozzles at the nozzle row as seen from a direction perpendicular to the scanning direction is set to correspond to a structural period as seen from a direction perpendicular to the scanning direction of the planar periodic pattern to be formed.
In the present invention, preferably, a difference between a phase difference between a periodicity of the planar periodic pattern in the scanning direction at a predetermined position as seen from a direction perpendicular to the scanning direction and another periodicity of the planar periodic pattern in the scanning direction at another position other than the predetermined position as seen from a direction perpendicular to the scanning direction, and a positional deviation as seen from the scanning direction between a predetermined nozzle corresponding to the predetermined position and another nozzle corresponding to the another position is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed, thereby forming a film.
In the present invention, preferably, a time difference is provided between a liquid drop supplying time of a predetermined nozzle disposed at a predetermined position as seen from the direction perpendicular to the scanning direction and a liquid drop supplying time of another nozzle disposed at another position other than the predetermined position as seen from the direction perpendicular to the scanning direction.
Further, preferably, a phase difference between a periodicity of the planar periodic pattern in the scanning direction at the predetermined position and another periodicity of the planar periodic pattern in the scanning direction at the another position, and a value obtained by multiplying the time difference and the scanning speed is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed, thereby forming a film.
In the present invention, preferably, the planar periodic pattern is obtained by arranging a plurality of colors of the filter elements in a planar periodic pattern, and the film-forming process is performed to at least one of the plurality of colors of the filter elements. When a plurality of colors of filter elements are arranged in a planar periodic pattern, the film-forming method of the present invention is applied to at least one color of the plurality of colors, thereby achieving a remarkable effect.
In the present invention, preferably, the film-forming process is performed to a blue color filter element. Particularly, the concentration difference (optical concentration) of the blue filter element is most noticeable. As a result, it is possible to reduce irregular color most effectively by application of the present invention when a film for the blue filter element is formed.
Next, the present invention provides a method for manufacturing a substrate for an electroluminescent device, having a film-forming step in which the liquid material is supplied onto the substrate to film-form a plurality of pixel regions in a planar periodic pattern having a predetermined periodicity. In the film-forming process, a liquid drop supplying means is used which is constructed to be capable of supplying a liquid drop at a predetermined driving period to deposit the liquid material on the object; the presence or absence of the supply of the liquid drop by the liquid drop supplying means is controlled at each driving period in accordance with the periodicity of the planar periodic pattern to be formed on the object; and the liquid drop is supplied by the control of the liquid drop supplying means while the liquid drop supplying means is scanned at a predetermined scanning speed in a predetermined scanning direction relative to the object. A natural number times a value obtained by multiplying the driving period and the scanning speed is set to be the structural period of the planar periodic pattern, to be formed on the object, in the scanning direction.
In the present invention, preferably, a step of scanning the liquid drop supplying means relative to the object in the scanning direction is performed several times and the operation of feeding the liquid drop supplying means to the object in a direction intersecting the scanning direction is performed during intervals between the scanning operations.
In the present invention, preferably, the liquid drop supplying means is provided with a nozzle row including a plurality of nozzles to supply the liquid drop, and the liquid drop supplying means is scanned relative to the object in the scanning direction in the position in which an arrangement period of the nozzles at the nozzle row as seen from a direction perpendicular to the scanning direction is set to correspond to a structural period as seen from a direction perpendicular to the scanning direction of the planar periodic pattern to be formed.
In the present invention, preferably, a difference between a phase difference between a periodicity of the planar periodic pattern, to be formed on the object, in the scanning direction, at a predetermined position as seen from a direction perpendicular to the scanning direction and another periodicity of the planar periodic pattern in the scanning direction at another position other than the predetermined position as seen from a direction perpendicular to the scanning direction, and a positional deviation as seen from the scanning direction between a predetermined nozzle corresponding to the predetermined position and another nozzle corresponding to the another position is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed, thereby forming a film.
In the present invention, preferably, a time difference is provided between a liquid drop supplying time of a predetermined nozzle disposed at a predetermined position as seen from the direction perpendicular to the scanning direction and a liquid drop supplying time of another nozzle disposed at another position other than the predetermined position as seen from the direction perpendicular to the scanning direction. A difference between a phase difference between a periodicity of the planar periodic pattern in the scanning direction at the predetermined position and another periodicity of the planar periodic pattern in the scanning direction at the another position, and a value obtained by multiplying the time difference and the scanning speed is set to 0 or a natural number times a value obtained by multiplying the driving period and the scanning speed, thereby forming a film.
In the present invention, the planar periodic pattern is obtained by arranging a plurality of colors of the pixel regions in a predetermined arrangement pattern, and preferably the film-forming process is performed to at least one of the plurality of colors of the pixel regions. When a plurality of colors of pixel regions are arranged in a planar periodic pattern, the film-forming method of the present invention is applied to at least one color of the plurality of colors, thereby achieving a remarkable effect.
In the present invention, preferably, the film-forming process is performed to a blue color pixel region. Particularly, the brightness intensity of the blue pixel region is easily noticeable, so that it is possible to reduce irregularity in film formation most effectively by application of the present invention when a film is formed with the blue pixel region.
also, the present invention provides a method for manufacturing a display device in which a plurality of pixels arranged at the planar periodic period is formed using any one of the film-forming methods described above.
Further, the present invention provides a method for manufacturing a display device in which a color filter substrate is formed using any one of the manufacturing methods described above.
Moreover, the present invention provides a method for manufacturing a display device in which a substrate for an electroluminescent device is formed using the manufacturing methods as described above.
Still further, the present invention provides a display device formed using the method for manufacturing a display device described above. According to this method, it is possible to construct a display device with high display quality by reducing the irregularity in film formation caused by the film-forming process. Particularly, in pixel rows arranged in the scanning direction, a greater improvement is made in the present invention than in the prior art because there is a smaller deviation in the film structure between pixels. As a result, it is possible to produce a display device with a reduction in the irregular color or brightness irregularity but with a remarkable increase in optical uniformity as compared with the prior art.
Also, the present invention provides an electronic apparatus comprising the aforementioned display device and control means for controlling the display device. The electronic apparatus of the present invention preferably includes all portable electronic apparatuses such as a portable information terminal including a portable telephone, a portable computer, and an electronic watch, although it is not limited thereto.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an embodiment of a film-forming method according to the present invention.
FIG. 2 is a plan view illustrating the film-forming method according to the present invention.
FIG. 3 is a plan view illustrating a modification of the film-forming method according to the present invention.
FIG. 4 illustrates the concept of the film-forming method shown in FIG. 3.
FIG. 5 is a structural view illustrating a liquid drop supplying means for implementing a film-forming method shown in FIG. 4.
FIGS. 6(a) and 6(b) illustrate a nozzle arrangement for implementing a film-forming method.
FIG. 7 is a plan view illustrating a planar periodic pattern of a delta arrangement.
FIG. 8 is a block view illustrating the structure of a drawing control unit.
FIGS. 9(a) to 9(d) are timing charts illustrating driving signals of a liquid drop supplying means.
FIG. 10 illustrates positions of supplying liquid drops to regions.
FIG. 11(a) illustrates measurement points of regions, and FIGS. 11(b) and 11(c) are brightness graphs of the measurement points.
FIG. 12(a) shows a deviation pattern of liquid drop supplying positions in a comparative example 1, FIG. 12(b) is a graph showing a positional deviation of the scanning direction in the comparative example 1, and FIG. 12(c) is a graph showing a positional deviation of the feeding direction in the comparative example 1.
FIG. 13(a) shows a deviation pattern of liquid drop supplying positions in an embodiment, FIG. 13(b) is a graph showing a positional deviation of the scanning direction in the embodiment, and FIG. 13(c) is a graph showing a positional deviation of the feeding direction in the embodiment.
FIG. 14(a) shows a deviation pattern of liquid drop supplying positions in a comparative example 2, FIG. 14(b) is a graph showing a positional deviation of the scanning direction in the comparative example 2, and FIG. 14(c) is a graph showing a positional deviation of the feeding direction in the comparative example.
FIG. 15 is a schematic perspective view illustrating the whole structure of a film-forming apparatus.
FIG. 16 is a partial perspective view illustrating main parts of the film-forming apparatus.
FIG. 17 illustrates the structure of a liquid drop supplying head.
FIG. 18 illustrates the structure of another liquid drop supplying head.
FIG. 19(a) is a perspective view illustrating the internal structure of a liquid drop supplying head, and FIG. 19(b) is a partial, longitudinal sectional view illustrating the internal structure of the liquid drop supplying head.
FIG. 20 is a block diagram illustrating the whole structure of a control system of a film-forming apparatus.
FIG. 21 is a schematic flowchart illustrating the operation of a film-forming apparatus.
FIG. 22 illustrates the structure of another liquid drop supplying head.
FIG. 23 is a schematic flowchart illustrating the processes of manufacturing a liquid crystal device.
FIG. 24 is an exploded perspective view of the liquid crystal device.
FIG. 25 is a longitudinal sectional view of the liquid crystal device cut along line IX-IX of FIG. 24.
FIG. 26 is a flowchart illustrating the processes of manufacturing an EL device (or a substrate for an EL device).
FIGS. 27(a) and 27(d) are sectional views illustrating the processes of manufacturing a color filter substrate.
FIGS. 28(a) to 28(d) are sectional views illustrating the processes of manufacturing an EL device.
FIG. 29(a) is a partial plan view illustrating a color filter arrangement on a mother substrate, FIG. 29(b) illustrates a method for forming a film on a mother substrate, and FIG. 29(c) illustrates a nozzle arrangement of the liquid drop supplying means.
FIGS. 30(A-1) to 30(A-4) and FIGS. 30(B-1) to 30(B-4) are sectional views illustrating an arrangement of liquid drops on regions.
FIGS. 31(a) to 31(c) are plan views of an arrangement of a liquid drop material within regions by supply of liquid drops.
FIGS. 32(a) to 32(c) illustrates an arrangement of the liquid material depending on differences in resolutions R1 to R3 when liquid drops are supplied.
FIG. 33 illustrates the relationship between a liquid drop supplying resolution and an arrangement of the liquid material in regions.
FIG. 34(a) is a graph illustrating a variation in brightness Y of the scanning direction, and FIG. 34(b) is a graph illustrating a variation in brightness Y of the feeding direction.
FIG. 35 is a block diagram illustrating the structure of a display control system in an electronic apparatus comprising the liquid crystal device 101.
FIG. 36 illustrates an external appearance as an embodiment of an electronic apparatus.
FIGS. 37(a) and 37(b) are plan views illustrating arrangement patterns of color filters.
DETAILED DESCRIPTION
Hereinafter, a detailed description of the invention will be made about a film-forming method, a film-forming apparatus, an apparatus and a method for manufacturing a color filter substrate, an apparatus and a method for manufacturing a substrate for an electroluminescent device, a method for manufacturing a display device, a display device and an electronic apparatus with reference to accompanying drawings.
Basic Construction of a Film-Forming Method and a Film-Forming Apparatus
First, a description will be made about a basic construction in an embodiment of a film-forming method and a film-forming apparatus according to the present invention. As shown in FIG. 15, a film-forming apparatus 16 (liquid drop discharge apparatus) of the present embodiment comprises: a head unit 26 having a liquid drop supplying head 22 (liquid drop discharge head) such as a liquid drop supplying head used in a printer or the like, a head position control unit 17 to control a position of the liquid drop supplying head 22, that is, a head position, a substrate position control unit 18 to control the position of an object (for example, a mother substrate 12), a scan driving device 19 as a scan driving means to scan and move the liquid drop supplying head 22 in the scanning direction X to the object (for example, mother substrate 12), feed driving means 21 to feed a liquid drop supplying head 22 to a feeding direction Y intersecting (perpendicular to) the scanning direction to the object, a substrate supply device 23 to supply the object (mother substrate 12) to a predetermined working position inside the film-forming apparatus 16, and a control unit 24 to control the film-forming apparatus 16 generally.
All of the aforementioned head position control unit 17, the substrate position control unit 18, the scan-driving device 19, the feed driving device 21 are installed on a base 9. Besides, such units are covered with a cover 14 if needed.
As shown in FIG. 17, for example, the liquid drop supplying head 22 includes a nozzle row 28 in which a plurality of nozzles 27 are arranged. For example, the number of the nozzles 27 is, for example, one hundred eighty, the diameter of the nozzles 27 is, for example, 28 μm, and the pitch t of the nozzles 27 is, for example, 141 μm. Reference direction S shown in FIG. 17 indicates a reference scanning direction of the liquid drop supplying head 22, and arrangement direction T indicates an arrangement direction of the nozzles 27 in the nozzle row 28.
As shown in FIGS. 19(a) and (b), the liquid drop supplying head 22 includes a nozzle plate 29 made of stainless steel or the like, a vibration plate 31 facing the nozzle plate 29, and a plurality of partition members 32 interconnecting the nozzle plate 29 and the vibration plate 31. A plurality of material chambers 33 and a liquid reservoir 34 are formed between the nozzle plate 29 and the vibration plate 31 by the partition members 32. The material chambers 33 and the liquid reservoir 34 are inter-connected through passages 38.
A material supplying hole 36 is formed at an appropriate position of the vibration plate 31. A material supplying unit 37 is connected to the material supplying hole 36. When forming color filters, the material supplying unit 37 supplies a liquid material M comprising a filter element material having one color, for example, red, among red (R), green (G) and blue (B) to the material supplying hole 36. The liquid material M supplied in this way fills the liquid reservoir 34 and fills the material chambers 33 through passages 38.
Nozzles 27 are formed in the nozzle plate 29 for discharging the liquid material M from the material chambers 33 in the shape of jet. Besides, material pressers 39 corresponding to the material chambers 33 are mounted on the rear surface of the vibration plate 31 facing the material chambers 33.
As shown in FIG. 19(b), a material presser 39 has a piezoelectric element 41 and a pair of electrodes 42a and 42b sandwiching the piezoelectric element 41 therebetween. The piezoelectric element 41 is bent and deformed to protrude externally as indicated by arrow C when electricity is applied to both electrodes 42a and 42b, resulting in an increase in the volume of the material chamber 33. As a result, the increased volume of the liquid material M flows into the material chamber 33 through the passage 38 from the liquid reservoir 34.
Thereafter, if the application of electricity to the piezoelectric element 41 stops, the piezoelectric element 41 and the vibration plate 31 returns to their original shapes and the material chamber 33 also returns to its original volume. Thus, the pressure of the liquid material M in the material chamber 33 rises, and the liquid material M turns into a liquid drop 8 to be discharged from the nozzle 27. In addition, in order to prevent the flying of the liquid drop 8 (path) from being bent and prevent the nozzle 27 from clogging, a liquid-repellent layer 43 made of a Ni-tetrafluoroethylene eutectoid plated layer is provided at the periphery of the nozzle 27.
Next, referring to FIG. 16, a description will be made about the head position control unit 17, the substrate position control unit 18, the scan driving device 19, the feed driving device 21 and the like, which are arranged at the periphery of the liquid drop supplying head 22. The head position control unit 17 includes α motor 44 to rotate the liquid drop supplying head 22 mounted to the head unit 26 in a plane (a horizontal plane), β motor 46 to rock and rotate the liquid drop supplying head 22 around an axis parallel to the feeding direction Y, γ motor 47 to rock and rotate the liquid drop supplying head 22 around an axis parallel in the scanning direction X, and z motor 48 to vertically translate the liquid drop supplying head 22.
Besides, the substrate position control unit 18 includes a table 49 to put an object (mother substrate 12) and θ motor 51 to rotate the table 49 in a plane (a horizontal plane). Also, the scan driving device 19 includes an X guide rail 52 extending in the scanning direction X and an X slider 53 built with, for example, a linear motor to be pulse-driven.
The X slider 53 is translated in the scanning direction X along the X guide rail 52, for example, by the operation of the built linear motor.
Further, the feed driving device 19 includes a Y guide rail 54 extending to the feeding direction Y and a Y slider 56 built with, for example, a linear motor to be pulse-driven. The Y slider 56 is translated to the feeding direction Y along the Y guide rail 54, for example, by the operation of the built linear motor.
In the X slider 53 or Y slider 56, the pulse-driven linear motor can precisely control the rotational angle of an output shaft with a pulse signal supplied to the motor. Therefore, it is possible to control a position on the scanning direction X of the liquid drop supplying head 22 supported by the X slider 53 or another position on the feeding direction Y of the table 49 in high precision. In addition, the position control of the liquid drop supplying head 22 or table 49 is not limited to the position control using a plus-motor, but can be completed by a feedback control using a servomotor or other certain methods.
The table 49 is provided with positioning means 50 constructed with pins that regulate the plane position of an object (mother substrate 12). The object (mother substrate 12) is positioned and kept while the end faces thereof in the scanning direction X and feeding direction Y are in contact with the positioning means 50 by a substrate supply device 23, which will be described later. It is preferable that commonly known fixing means such as air suction (vacuum absorption) is arranged on the table 49 so as to fix the object (mother substrate 12) that has been held in the aforementioned positioned state.
The description will be continued referring back to FIG. 15. The substrate supply device 23 illustrated in FIG. 15 includes a substrate accommodating part 57 to accommodate an object (mother substrate 12) and a substrate transfer mechanism 58 such as a robot that conveys the object (mother substrate 12). The substrate transfer mechanism 58 includes a base 59, an elevating shaft 61 which is elevated with respect to the base 59, a first arm 62 to rotate about the elevating shaft 61, a second arm 63 to rotate with respect to the first arm 62, and an absorption pad 64 provided at the underside of the second arm 63 at the tip thereof. The absorption pad 64 is constructed to absorb and hold the object (mother substrate 12) by suction (vacuum absorption) or the like.
Further, as shown in FIG. 15, a capping device 76 and a cleaning unit 77 are located below the scanning locus of the liquid supplying head 22 and disposed at one side position of the feed driving device 21. Besides, an electronic balance 78 is installed at the other side position of the feed driving device 21. In this case, the capping device 76 is to prevent the drying of the nozzle 27 (see FIG. 17) when the liquid drop supplying head 22 is in a stand-by state. The cleaning unit 77 is to clean the liquid drop supplying head 22. The electronic balance 78 is to measure the amount of a liquid drop 8 to be discharged from each nozzle 27 in the liquid drop supplying head 22. Moreover, a head camera 81 that integrally moves with the liquid drop supplying head 22 is mounted around the liquid drop supplying head 22.
The control unit 24 shown in FIG. 15 includes a computer main body 66 accommodating a processor, an input unit 67 such as a keyboard, and a display device 68 such as CRT. The computer main body 66 includes a central processing unit (CPU) 69 shown in FIG. 20, and an information recording medium 71 that is a memory for storing a variety of information.
Respective devices such as the head position control unit 17, substrate position control unit 18, scan driving device 19, feed driving device 21, and head driving circuit 72 that drives a piezoelectric element 41 (refer to FIG. 19(b)) in the liquid drop supplying head 22, as shown in FIG. 20, are connected to CPU 69 via an input/output interface 73 and a bus 74. Besides, the substrate supply device 23, input unit 67, display device 68, capping device 76, cleaning unit 77, and electronic balance 78 are connected to CPU 69 via the input/output interface 73 and bus 74 similarly to the above construction.
The memory as an information recording medium 71 includes all external memory devices such as a semiconductor memory such as random access memory (RAM) and read only memory (ROM), a hard disc, a CD-ROM reading device, and a disc-type recording medium. The memory is functionally classified into a memory region to store a software program of describing an operational control procedure of a film-forming apparatus 16, a memory region for storing the positions of an object (mother substrate 12) where the liquid drop supplying head 22 supplies liquid drops as coordinate data, a memory region for storing the feeding amount of the object (mother substrate 12) to the feeding direction Y shown in FIG. 16, a region for functioning as a work area or a temporary file for CPU 69, and the other various memory regions.
CPU 69 performs a control to supply (discharge) liquid drops to a predetermined position on the surface of the object (mother substrate 12) according to the software program stored in the memory that is the information memory medium 71. As shown in FIG. 20, specific function-implementing units includes a cleaning operation unit that performs an operation for implementing a cleaning process, a capping operation unit for implementing a capping process, a weight-measuring operation unit for implementing the measurement of weight using the electronic balance 78, and a drawing operation unit 690 for discharging and depositing liquid drops to the surface of the object (mother substrate 12) and drawing a predetermined pattern b.
The drawing operation unit 690 includes a variety of functional operation units such as a drawing start position operation unit for installing the liquid drop supplying head 22 at an initial position for drawing, a scanning control operation unit for performing an operation that makes a control to scan and move the liquid drop supplying head 22 at a predetermined speed in the scanning direction X, a feeding control operation unit for performing an operation that makes a control to shift the object (mother substrate 12) by a preset feeding amount to the feeding direction Y, and a nozzle discharge control operation unit for performing an operation that makes a control on whether any one of the plurality of nozzles 27 in the liquid drop supplying head 22 is operated to discharge ink.
In addition, in the present embodiment, the aforementioned functions are implemented with the software program using CPU 69. However, if the functions can be implemented by an electronic circuit that does not use the CPU, they can also be implemented using such an electronic circuit.
Next, the operation of the film-forming apparatus 16 thus constructed will be described based upon a flowchart shown in FIG. 21. If the film-forming apparatus 16 operates with the input of electricity by an operator, initial setting is performed in step S1. Specifically, the head unit 26, the substrate supply device 23, and the control unit 24 are set to their predetermined initial states.
Next, if the weight measurement timing arrives (step S2), the scanning driving device 19 moves the head unit 26 shown in FIG. 16 to a place where the electronic balance 78 is placed as shown in FIG. 15 (step S3). Then, the electronic balance 78 is used to measure the amount of ink discharged from the nozzle 27 (step S4). According to a characteristic in the amount of the material discharged from the nozzle 27 thus measured, a voltage to be applied to the piezoelectric element 41 of each nozzle 27 is controlled (step S5).
Thereafter, when the cleaning time arrives (step S6), the head unit 26 is moved by the scan driving device 19 to a place where the cleaning unit 77 is positioned (step S7), and the liquid drop supplying head 22 is cleaned by the cleaning unit 77 (step S8).
If the weight measurement time or cleaning time does not arrive, or if the weight measurement or cleaning is completed, the substrate supply device 23 shown in FIG. 15 is operated to supply the object (mother substrate 12) to the table 49 in step S9. Specifically, while the object (mother substrate 12) placed in the substrate accommodating part 57 is sucked (vacuum adhered) and held by the absorption pad 64, the elevating shaft 61, the first and second arms 62, 63 are moved to convey the object (mother substrate 12) to the table 49, and press the object against the positioning means 50 previously provided at a proper position of the table 49. In addition, it is preferable that the object (mother substrate 12) is fixed to the table 49 by the air suction (vacuum absorption) means to prevent the object (mother substrate 12) from being dislocated on the table 49.
Next, an output shaft of the θ motor 51 is rotated in units of tiny angles to rotate the table 49 within the plane (horizontal plane), thereby positioning an object (mother substrate 12) (step S10). Then, while the object (mother substrate 12) is observed by the head camera 81 shown in FIG. 15, a position of starting a drawing with the liquid drop supply head 22 is determined by an operation (step S11). Then, the scan driving device 19 and the feed driving device 21 are properly operated to move the liquid drop supplying head 22 to a drawing start position (step S12).
At this time, the liquid drop supplying head 22 may take such a position that the reference direction S shown in FIG. 17 coincides with the scanning direction X, or, as shown in FIG. 29(b), may be constructed that the reference direction S is inclined in the scanning direction X at a predetermined angle of inclination. There is often a difference between the pitch of the nozzles 27 and that of a position of an object where ink is to be deposited. Thus, the angle of inclination is used as measures to make the dimension component of the pitch of the nozzles 27, in the feeding direction Y, arranged to the arrangement direction T, geometrically equal to the pitch at the depositing position onto the object (mother substrate 12) in the feeding direction Y when the liquid drop supplying head 22 is moved in the scanning direction X.
If the liquid drop supplying head 22 is placed at the drawing start position in step S12 shown in FIG. 21, the liquid drop supplying head 22 is scanned and moved linearly in the scanning direction X at a constant level of speed in step S13. While the liquid drop supplying head 22 is scanned, a liquid drop is discharged from the nozzle 27 of the liquid drop supplying head 22 to the surface of the object (mother substrate 12).
In addition, the amount of a liquid drop may be set to discharge the whole amount of the liquid drop within a range of discharge that can be covered by the liquid drop supplying head 22 with one-time scanning process. For example, as described later, if the liquid drop supplying head 22 is constructed to discharge only a fractional portion (for example, one fourth) of the amount of the liquid material to be originally discharged at one-time scanning process, and if the liquid drop supplying head 22 is scanned several times, the liquid drop supplying head 22 may be constructed such that the scanning range thereof partially overlaps the feeding direction Y and the discharge of the liquid material is performed to all the areas several times (for example, four times).
When the scanning process for one line of the object (mother substrate 12) is completed (step S14), the liquid drop supplying head 22 returns to its initial position (step S15), and moves to the feeding direction Y by a predetermined amount (the set feeding amount) (step S16). At this time, the scanning process is again performed to discharge the liquid material in step S13, and, then, the aforementioned processes are repeated to perform the scanning processes over a plurality of lines. In this case, if the scanning process for one line is completed, the liquid drop supplying head 22 may be scanned in returns such that it is moved by a predetermined amount to the feeding direction Y and it is returned to perform the scanning process in reverse.
At this time, a description will be made about a case that a plurality of color filters are formed in the mother substrate 12. If all the filter element materials are discharged to one row of the color filter region in the mother substrate 12 is completed (step S17), the liquid drop supplying head 22 is moved by a predetermined amount to the feeding direction Y to repeat the operation of the aforementioned steps S13 to S16. Then, if the filter element materials are completely discharged to all rows of the color filter region of the mother substrate 12 (step S18), the mother substrate 12 is ejected outside after treatment by the substrate supply device 23 or other conveying mechanism in step S20. Thereafter, as long as there is no operation completion command from an operator, the operation for supplying the mother substrate 12 and for discharging liquid drops will be repeatedly performed.
If there is an operation completion command from an operator (step S21), CPU 69 conveys the liquid drop supplying head 22 to a place where the capping device 76 shown in FIG. 15 is positioned, and the capping device 76 performs a capping process to the liquid drop supplying head 22 (step S22).
While the liquid drop supplying head 22 is scanned in the scanning direction X, the film-forming apparatus 16 thus constructed discharges liquid drops of ink continuously and repeatedly performs the scanning through the movement to the feeding direction Y (feeding operation). As a result, the liquid material is two-dimensionally deposited to a predetermined region on the surface of the object (mother substrate 12), thereby forming a film.
Generally, the discharge amount of the plurality of nozzles 27 composing the nozzle row 28 of the liquid drop supplying head 22 is not necessarily identical. Instead, there is a tendency that the discharge amount gets greater at several nozzles (for example, ten nozzles at each side) 27 positioned at both ends of the nozzle row 28. In this way, it is not preferable to use nozzles 27 having a greater amount of discharge than the other nozzles 27, in that the thickness of a film to be formed by discharge of ink is not uniform. Therefore, preferably, several nozzles, for example, about ten nozzles, positioned at both ends E of the nozzle row 28, among the plurality of nozzles 27 composing the nozzle row 28, are previously set not to discharge ink, and only the nozzles 27 positioned at the other parts of the nozzle row 28 are used.
Besides, it is possible to reduce the irregularity in the thickness of the formed film by using a plurality of liquid drops instead of just a single liquid drop discharged from the liquid drop supplying head 22 when a film-forming process is carried out at a predetermined area of an object. In other words, when a film-forming process is performed in a plurality of areas and a plurality of liquid drops are used for each area, there will be reduced irregularity in the thickness of a film to be formed at respective areas even if there may be more or less irregularity in the amount of respective liquid drops.
The scope of the invention is not limited to the structure of the liquid drop supplying head 22 described above, but there may be many other structures for constructing the liquid drop supplying head. For example, a liquid drop supplying head 22A shown in FIG. 18 includes two nozzle rows 28 arranged in the reference direction S and a plurality of nozzles 27 are included in both nozzle rows 28. Further, the liquid drop supplying head 22B illustrated in FIG. 22 includes three nozzle rows 28R, 28G, 28B arranged in the reference direction S. In either of the liquid drop supplying heads 22A, 22B, the material of liquid drops to be discharged from the nozzles 27 of each nozzle row 28 may be the same or different. For example, the liquid drop supplying head 22A shown in FIG. 18 is constructed to discharge the same material of liquid drops from the nozzles 27 in either of the two nozzle rows 28. However, in the liquid drop supplying head 22B shown in FIG. 22, the liquid material to be discharged from the nozzles 27 of each nozzle row 28R, 28G, 28B is different, for example, filter element materials 13R, 13G, 13B which will be described below may be used.
Details of a Film-Forming Method and a Film-Forming Apparatus
Next, a detailed description will be made about the characteristics of the film-forming method and the film-forming apparatus according to the present invention. The following descriptions will be related to a general structure, not directly related to the specific structure of the film-forming method and apparatus. Therefore, the structure of the present embodiment can be recognized in the general structure and also in the specific film-forming method and apparatus shown in FIGS. 15 to 22.
FIG. 1 illustrates the principles of the film-forming method and apparatus of the present embodiment. First, an object 1 such as a substrate is arranged, and a liquid drop supplying means 2 (corresponding to the liquid drop supplying head 22 described above) to supply a liquid drop 4a to the surface of the object 1 is arranged to face the object 1. The liquid drop supplying means 2 is constructed to be capable of relatively scanning the object 1 in the scanning direction X. In this case, the object 1 is moved in the scanning direction X at the scanning speed Vx in the illustrated embodiment. On the contrary, the liquid drop supplying means 2 may be moved, and both the object 1 and the liquid drop supplying means 2 may also be moved. In the illustrated embodiment, only the positive direction of the scanning direction X is set as a direction to which the object 1 is moved, but it may be set as the relative movement direction of the liquid drop supplying means 2. In any event, it is preferable to get the sign of various parameters (δx, δd) uniformly set in a certain direction.
The liquid drop supplying means 2 is driven by a driving signal 3a output from driving means 3. For example, the driving means 3 comprises an appropriate driving circuit to output the driving signal 3a. The driving signal 3a outputted by the driving means 3 is a periodic signal having a driving period Td (a reverse number of driving frequency Fd). When one liquid drop 4a is discharged from a nozzle 2a of the liquid drop supplying means 2 by a driving waveform of a driving period Td, the driving signal 3a is made to supply a liquid material 2b onto the surface of the object 1. Therefore, if liquid drops 4a are continuously discharged, predetermined driving waveforms appear repeatedly at the driving period Td. When liquid drops 4a need not be discharged for a certain period of time, there will be no driving waveform in the predetermined driving period Td of the driving signal 3a equivalent to the certain period of time. In other words, the driving means 3 is constructed to determine whether a driving waveform is formed at every driving period Td of the driving signal to drive the liquid drop supplying means 2.
The liquid drop supplying means 2 can discharge liquid drops 4a with the driving signal 3a at every driving period Td. Thus, when the liquid drop supplying means 2 is relatively scanned to the object 1 at the scanning speed Vx, the resolution Rx of the liquid drop supplying position on the surface of the object 1 is obtained by multiplying driving period Td and scanning speed Vx. That is, Rx=Td×Vx. The resolution Rx is a minimum gap of the liquid drop supplying positions when liquid drops 4a is continuously discharged by the liquid drop supplying means 2 in the scanning direction X.
FIG. 2 is a plan view illustrating the relationship between a planar periodic structure 1P arranged on the surface of the object 1 and a liquid material 4b that will be supplied in accordance with the planar periodic structure 1P. The planar periodic structure 1P is constructed to form a film with the liquid material 4b that has been deposited and arranged by a liquid drop 4a supplied by the liquid drop supplying means 2. For example, in an example shown in FIG. 2, there is a periodic structure having regions P arranged horizontally and vertically with a gap on the surface of the object 1. In this structure, regions P are arranged with almost an identical gap in both directions, the vertical scanning direction X in the drawing and the horizontal feeding direction Y in the drawing. In this case, the structural period of scanning direction X and that of feeding direction Y are respectively indicated by Dx and Dy in the planar periodic structure 1P. Additionally, the scanning direction X and the feeding direction Y are positioned perpendicular to each other in the illustrated example, but they need not be positioned perpendicular to each other. They may simply be positioned to intersect each other. The planar periodic structure 1P is patterned to have no phase difference in the periodicity of scanning direction X in rows Y1 to Y5 of two regions P at two different positions as seen from the feeding direction Y perpendicular to scanning direction X.
When the planar periodic structure 1P described above is constructed, liquid drops 4a are discharged to the regions P supposedly assigned on the surface of the object 1, and the liquid material 4b is arranged within the corresponding regions P. At this time, in the present embodiment, the natural number times of the resolution Rx (=Td×Vx) is set to be the structural period Dx of the scanning direction X in a planar periodic structure 1P to be formed. In other words, Dx=n×Rx (n is a natural number). Then, when the liquid drop supplying means 2 is relatively scanned to the object 1 in the scanning direction X to discharge the liquid drop 4a as shown in FIG. 1, the liquid material 4b can be arranged within a plurality of corresponding regions P arranged in the scanning direction X, as shown in FIG. 2. For example, if the liquid material 4b is arranged substantially at the center of a certain region P as in the illustrated example, it is possible to make the liquid material 4b arranged substantially at the center of another region P. Accordingly, it is possible to reduce irregularity in the arrangement of the liquid material 4b in a plurality of regions P arranged in the scanning direction X, which results in a decrease in the unevenness of a formed film.
At this time, if the liquid drop supplying means 2 has only a single nozzle 2a as indicated by a single dot chain line, for example, a row Y2 of region P shown in FIG. 2 is scanned in the scanning direction X and the liquid drop 4a is discharged to arrange the liquid material 4b. Then, a feeding process is performed to feed the liquid drop supplying means 2 as much as the structural period Dy in feeding direction Y Thereafter, the aforementioned scanning process is performed to a row Y3 of another region P and the liquid drop 4a is discharged to arrange the liquid material 4b. The same process is repeated to rows Y4, Y5 arranged in the scanning direction X, so as to arrange liquid drops one after another. As a result, there can be formed a planar periodic structure 1P having periodicity in both vertical and horizontal directions.
However, the liquid drop supplying means 2 need not be constructed with only a single nozzle 2a, but may include a plurality of nozzles 2a. For example, a plurality of nozzles 2a is arranged along an arrangement direction 2b in liquid drop supplying means 2′ illustrated in the drawing. In this case, by making the arrangement period of nozzles 2a equal to the structural period of the planar periodic structure 1P as seen from a direction intersecting the scanning direction X, a plurality of nozzles 2a make it possible to arrange the liquid material to a plurality of rows Y1 to Y5 at one time. In the illustrated example, the structural period Dy of the planar periodic structure 1P as seen from the feeding direction Y coincides with the arrangement period of nozzles 2a while the feeding direction Y perpendicular to the scanning direction X is made to coincide with the arrangement direction 2b of the nozzles 2a in the liquid drop supplying means 2′. At this time, if a liquid drop 2a is discharged by the liquid drop supplying means 2′, there can, be almost no irregularity in the arrangement of the liquid material 4b in regions P arranged in the feeding direction Y as well as in the regions P arranged in the scanning direction X. In addition, even when the liquid drop supplying means 2′ having a plurality of nozzles as such is used, the scanning step can be performed several times with an insertion of a feeding operation to the feeding direction Y, similarly to the liquid drop supplying means 2 described above. Besides, when a plurality of liquid drops are supplied to respective regions P to form a planar periodic structure 1P, the sequential scanning step can be repeatedly performed with an insertion of a feeding operation in which the liquid drop supplying means 2′ having a plurality of nozzles is fed with fewer rows than the number of nozzles in the feeding direction Y. Thus, it is possible to reduce the unevenness in film forming, which is caused by the irregularity in the discharge amount of the liquid material between a plurality of nozzles.
FIG. 3 is a plan view illustrating the relationship with a planar periodic structure 1P to be formed in the object 1 when a liquid drop supplying means 2″ different from the one described above is used. At this time, a plurality of nozzles 2a are arranged in the arrangement direction 2b in the liquid drop supplying means 2″. Here, a gap between such nozzles 2a is designated as Np. Also, a structural period of the planar periodic structure 1P in the scanning direction X and a structural period thereof in the feeding direction Y are respectively designated as Dx and Dy. In this example, there is a difference between the structural period Dy as seen from the feeding direction Y perpendicular to the scanning direction X and the nozzle gap Np of the liquid drop supplying means 2″. Therefore, the arrangement direction 2b of the nozzles 2a in the liquid drop supplying means 2″ is inclined at an angle θ with respect to the feeding direction Y so as to make the gap (Np·cos θ) of the feeding direction Y of nozzles 2a coincide with the structural period Dy.
When the liquid drop supplying means 2″ is scanned in the scanning direction X to discharge the liquid drop in the above described position, the supplying position of the liquid drop is made to coincide with the periodicity of the planar periodic structure 1P in the feeding direction Y. However, if the arrangement direction 2b of nozzles 2a is inclined with respect to the feeding direction Y, there may be a positional deviation δx of the scanning direction X, δx=Np·sin θ=Dy·tan θ between adjacent nozzles 2a. The positional deviation δx depends on the angle θ of inclination set to make the nozzle gap of the liquid drop supplying means 2″ equal to the structural period Dy of the scanning direction Y. In general, the positional deviation is not limited to that equal to the natural number times of the resolution Rx (refer to FIG. 1). Therefore, when liquid drops are simultaneously discharged from a plurality of nozzles 2a of the liquid drop supplying means 2″ (for example, when all the nozzles are operated by a common driving signal), and, for example, if liquid drops are discharged to arrange the liquid material 4b at the center of the row Y3 of region P arranged in the illustrated scanning direction X, the liquid material may be arranged at positions deviated from the center of the region P, in case of rows Y1, Y2, Y4, Y5, other than the row Y3, as illustrated with a dot line. More specifically, in case of rows Y2, Y4 neighboring the row Y3, the positions of the liquid drop may be deviated as far as δx in the scanning direction X from the center of region P. In case of rows Y1, Y5 opposite to the rows Y2, Y4, respectively, the positions of the liquid drop may be deviated as far as δx in the scanning direction X from the center of region P. In other words, if the nozzles 2a are arranged with an identical gap, the positional deviation of respective nozzles in the scanning direction X is iδx (i is a natural number). For example, in case of the illustrated example, if there are nozzles at the position of reference numeral 2a(4)′, there will be no problem. However, the nozzles 2a(4) are actually deviated as far as δx in the scanning direction X from the nozzle 2a(3). Therefore, when liquid drops are discharged simultaneously from the nozzles 2a(3) and 2a(4), the supplying position of the liquid drop is deviated as far as δx in the scanning direction X.
In actuality, the driving period to supply the liquid drop in nozzles 2a(3) corresponding to the row Y3 and that in nozzle 2a corresponding to the other rows are made different depending to the positional deviations δx, 2δx by the driving means 3 shown in FIG. 1, so that it is possible to make the positional deviation of the liquid material in the scanning direction X smaller than δx. However, it is impossible to completely eliminate the positional deviation in the scanning direction X in the arrangement of the liquid material 4b at regions P arranged in the feeding direction Y as long as the positional deviation δx is not natural number times of resolution Rx as described above. Therefore, there may be periodic deviation of the liquid material in the feeding direction Y, a stripe pattern of a formed film in the feeding direction Y (color or brightness irregularity in case of a color filter or a luminous body) may occur.
Accordingly, the position of nozzles 2a may be deviated in the scanning direction X to compensate the positional deviations δx, 2δx. For example, as shown in FIG. 4, in case of nozzles 2a(1), 2a(2), 2a(3) respectively corresponding to rows Y1, Y2, Y3, there are deviations δx, 2δx respectively between nozzle 2a(1) and nozzle 2a(2) and between nozzle 2a(1) and nozzle 2a(3). At this time, if the positions of nozzle 2a(2) and nozzle 2a(3) are corrected in reverse in the scanning direction X (a vertical direction as illustrated) as far as they are deviated, so as to eliminate a positional deviation of the liquid drop supplying position, which is caused by positional deviations of nozzles.
However, the correction amount of nozzle positions of the liquid drop supplying means 2 is a distance corresponding to an angle of inclination θ, δx=Np·sin θ. In the case that a plurality of nozzles are provided, the correction amount of nozzles spaced apart from each other is great. It is generally difficult to construct the material chamber that can receive such a great correction amount without problem. Therefore, in order to reduce the correction amount, the positional correction amount of nozzles 2a can be obtained as a remainder of a natural number quotient m when δx is divided by resolution Rx, instead of δx, or as a value when the remainder is subtracted from the resolution Rx (hereinafter, simply referred to as ‘remainder value’), Sx=δx−m·Rx (m is a natural number), or Sx=2δx−m·Rx. In this case, the natural number m is a natural number that satisfies (m−1)·Rx<δx<m·Rx, or, m·Rx<δx<(m+1)·Rx (or, (m−1)·Rx<2δx<m·Rx, or, m·Rx<2δx<(m+1)·Rx). In the aforementioned method, it is possible to achieve a significant reduction in the positional correction amount of nozzles 2a.
In the structure thus constructed, it is necessary to independently control a plurality of nozzles 2a of the liquid drop supplying means 2″. For example, as shown in FIG. 5, it may be considered that the liquid drop supplying means 2″ is provided with a plurality of independent liquid drop supplying structures 2A respectively having nozzles 2a. The independent liquid drop supplying structures 2A may discharge the liquid drop according to separate driving waveforms when driving signals 3a are separately received from the driving means 3. A plurality of driving signals 3a corresponding to the plurality of liquid drop supplying structures 2A are set to have a driving waveform sent by a synchronized common driving period. However, such a driving waveform may be different with each of the plurality of driving signals 3a. Therefore, it is possible to independently select whether the liquid drop is discharged at a certain driving period or not for each of the plurality of nozzles 2a.
Further, as in the liquid drop supplying means 2P shown in FIG. 6(a), an aspect of correcting the position of nozzles 2a may be considered in which the positions of the nozzles 2a(+1) and 2a(−1) at both sides of a certain nozzle 2a(0) are corrected to deviate from their original positions to the direction perpendicular to the arrangement direction 2b of nozzles, and they are finally placed at the aforementioned optimum positions of nozzles. In addition, as in the liquid drop supplying means 2Q shown in FIG. 6(b), another aspect of correcting the position of nozzles 2a may be considered in which an angle of inclination θ corresponding to a planar periodic pattern 1p with respect to the original positions of nozzles is obtained and the positions of the nozzles are inclined to make an angle intersecting the arrangement direction 2b equal to the angle of inclination θ.
Instead of correcting the positions of nozzles 2a as described above, it may be possible to respectively delay the liquid drop supplying timings of nozzle 2a(2) or nozzle 2a(3) as much as δt=δx/Vx and 2δt=2δx/Vx in comparison with the liquid drop supplying timing of the nozzle 2a(1) shown in FIG. 4. In this case, it is necessary to independently control the discharge of the liquid drop at each nozzle. The structure illustrated in FIG. 5 can be employed as the liquid drop supplying means 2″. In this case, the remainder value Sx is used to set the difference in the supplying timings between nozzles 2a to δts=Sx/Vx=(δx−m·Rx)/Vx (or =(2δt−m·Rx)/Vx) instead of δt, 2δt. In this case, the natural number m is a natural number to satisfy (m−1)·Rx<δx<m·Rx, or, m·Rx<δx<(m+1)·Rx (or, (m−1)·Rx<2δx<m·Rx, or, m·Rx<2δx<(m+1)·Rx). The aforementioned methods make it possible to minimize time differences in the liquid drop supplying timings among a plurality of nozzles.
FIG. 8 is a block diagram illustrating the drawing operation unit 690 with a different structure. Function implementing means of the drawing operation unit 690 includes a liquid drop supplying control means 691 for controlling discharge of the liquid drop as a whole, driving signal generating means 692 for generating a driving signal having a predetermined driving frequency Fd (driving period Td) under the control of the liquid drop supplying control means 691, driving frequency setting means 693 for setting a driving frequency Fd or driving period Td of the driving signal generating means 692, and driving waveform selecting means 694 for selecting a driving waveform of a driving signal outputted from the driving signal generating means. A predetermined driving signal 3a shown in FIG. 9(a) is outputted by the driving waveform selecting means 694.
The driving frequency setting means 693 can set the driving frequency Fd (or driving period Td) of the driving signal generating means 692. Then, the driving frequency Fd is set to adjust the resolution Rx=Td×Vx to an appropriate value. Therefore, without a change in the scanning speed Vx, the resolution Rx can be modified or adjusted so as to make the liquid drop supplying positions of the scanning direction X uniform and improve a film-forming quality without deteriorating the manufacturing efficiency.
Besides, position controlling means 696 is provided that is controlled by the liquid drop supplying controlling means 691. The position controlling means 696 controls and drives driving mechanism 5 (equivalent to the head position control unit 17, substrate position control unit 18, scan driving device 19, feed driving unit 21, head driving circuit 72) that operates the liquid drop supplying means 2 (equivalent to the liquid drop supplying head 22) or the object 1.
In the present embodiment, driving signal adjusting means 695 is provided to supply a different driving signal 3a to each of the plurality of nozzles shown in FIG. 5. The driving signal adjusting means 695 forms independent driving signals having driving waveforms for driving periods respectively necessary at each plurality of nozzles on the basis of the driving waveforms (see FIG. 9(a)) outputted from the driving waveform selecting means 694. For example, as shown in FIG. 9(b), individual driving signals determine whether a driving waveform will be formed or not at a certain driving period Td at each nozzle. In addition, if only a single driving signal is needed, the driving signal adjusting means 695 is not required.
As shown in FIG. 9(c) or (d), the aforementioned driving signals may have a phase difference as great as the time difference of the supplying timings δts with respect to the driving signal (a) or (b) corresponding to a reference nozzle. Further, it is possible to delay the liquid drop supplying timings among nozzles correspondingly to the time difference δts. Thus, a plurality of driving signals having the aforementioned time difference at the driving period is applied to liquid drop supplying structures 2A respectively provided at the plurality of nozzles 2a. As a result, it is possible to restrict irregularity in liquid drop supplying positions between the regions P in the feeding direction Y according to the aforementioned principle.
Embodiment
Next, more specific embodiments corresponding to the aforementioned description will be described below. FIG. 7 illustrates a planar periodic pattern (color pattern) 1P′ referred to as a delta arrangement. A specific embodiment of the planar periodic pattern 1P′ may include an arrangement pattern of filter elements of a color filter or an arrangement pattern in a light emitting area of an EL device, which will be described below. One of a plurality of types of color elements R, G, B is formed in a plurality of regions P arranged in the planar periodic pattern 1P′. In this case, a structural period as seen from the scanning direction X in the planar periodic pattern 1P′ is classified into a small structural period dx, when the regions P of all the color elements R, G, B are regarded as an identical structural unit, and into a large structural period Dx when the color elements R, G, B are respectively regarded as a different structural unit. Similarly to this, a structural period as seen from the feeding direction Y in the planar periodic pattern 1P′ is classified into a small structural period dy, when the regions P of all the color elements R, G, B are regarded as an identical structural unit, and into a large structural period Dy when the color elements R, G, B is respectively regarded as a different structural element.
In the present embodiment, different liquid drop supplying means 2R, 2G, 2B are respectively utilized for color elements R, G, B in case of the planar periodic pattern 1P′ having the aforementioned delta arrangement. If attention is paid to only one of those color elements R, G, B, it is possible to perform a film-forming method similar to that described above while the planar periodic pattern 1P′ is regarded as a planar periodic structure in which only a region P having only one type color element (for example, R) with structural periods Dx, Dy arranged.
In addition, the planar periodic pattern 1P′ having the delta arrangement is different from the one shown in FIGS. 1 to 3 which has a positional relationship among rows Y1 to Y6 of regions P arranged in the scanning direction X. In other words, there are two different positions as seen from the direction perpendicular to the scanning direction X, that is, the feeding direction Y, in the planar periodic pattern 1P′. For example, there exists a half period in periodicity of the scanning direction X, that is, a phase difference equivalent to half (πrad(180 degrees)) a structural period Dx. This is completely similar to a case when attention is paid to a region P of a color element R. Accordingly, as shown in FIGS. 1 to 3, in the case that the periodicity of the scanning direction X has the same phase for all the rows Y1 to Y5 as the relationship of the liquid dr