DETAILED DESCRIPTION

[0043] FIG. 1 illustrates a light emitting device according to a first embodiment of the present invention. The light emitting device 10 of FIG. 1 includes a plurality of OLED modules 12 . FIG. 1 illustrates two OLED modules 12 . In one embodiment of the present invention, the number of OLED modules is greater than two. The OLED modules 12 are arranged such that they are connected in series with one another.

[0044] Each of the individual OLED modules 12 has an anode 14 and a cathode 16 . The OLED modules 12 are electrically connected in a series arrangement, anode 14 to cathode 16 , as shown in FIG. 1 . In this regard, the respective anodes and cathodes are typically electrically connected via interconnect wiring 18 as shown in FIG. 1 .

[0045] The light emitting device 10 also includes a power source 20 to provide a voltage to the OLED modules 12 . The power source 20 provides power to the plurality of OLED modules 12 via first conducting line 22 and second conducting line 24 . The conducting lines 22 and 24 , are electrically connected to a respective end anode 14 and respective end cathode 16 of the plurality of OLED modules 12 .

[0046] Exemplary light emitting device configurations are provided in the commonly assigned patent application General Electric Docket No. RD-27258-11, AC Powered OLED Device, A. Duggal et al., which is incorporated herein by reference in its entirety.

[0047] In one embodiment of the present invention, the power source 20 is a DC power source. In another embodiment of the present invention, the power source 20 is an AC power source.

[0048] In one embodiment of the present invention, at least two OLED modules 12 are connected in series. The OLED modules 12 on each end of the series are electrically connected to only one other OLED module 12 . In this case, the conducting lines 22 and 24 are respectively connected with the anode 14 and cathode 16 of the respective OLED modules disposed on the ends of the series. Thus, the power source 20 provides a voltage to each of the OLED modules 12 of the plurality of OLED modules 12 .

[0049] The power source 20 and the plurality of OLED modules 12 are shown in FIG. 1 as arranged on a substrate 26 . However, the plurality of OLED modules 12 and the power source 20 need not be arranged on a single substrate. In fact, neither the plurality of OLED modules 12 nor the power source 20 need be arranged on the substrate 26 .

[0050] FIG. 1 shows a light emitting device 10 with only a single group of OLED modules 12 arranged in a series configuration. However, the first embodiment of the present invention is not so limited. In one embodiment of the present invention, the light emitting device 10 of the first embodiment comprises more than one group of OLED modules 12 , and the OLED modules 12 of each group is arranged in a series configuration. In this case, the groups are electrically connected with each other in a parallel configuration.

[0051] FIG. 2 illustrates a second embodiment of the present invention. A light emitting device 30 of the second embodiment is seen connected to a power source 32 . The light emitting device 30 includes a substrate 34 and a plurality of OLED series groups 36 provided on the substrate 34 . In one embodiment of the present invention, the substrate 34 is comprises a transparent glass.

[0052] In one embodiment of the present invention, the power source 32 is a DC power source. In another embodiment of the present invention, the power source 20 is an AC power source.

[0053] Each of the OLED series groups 36 comprises a plurality of individual OLED modules 38 . When a voltage is provided from the power source 32 to the OLED modules 38 , the OLED modules 38 emit light.

[0054] As with the first embodiment, each of the OLED modules 38 in the second embodiment includes the anode 42 and the cathode 44 . The OLED modules 38 of a particular series group are electrically connected in series, i.e., an anode 42 of one OLED module 38 to a cathode 44 of an adjacent OLED module 38 .

[0055] FIG. 2 shows that adjacent OLED modules 38 in a particular series group 36 are connected anode 42 to cathode 44 . However, it is not required that adjacent OLED modules 38 in a particular series group 36 be so connected. In one embodiment of the present invention, a particular OLED module 38 in a series group 36 is connected to another OLED module 38 , where that other OLED module 38 is not immediately adjacent or the closest OLED module 38 to the particular OLED module 38 . However, in any case, all the OLED modules 38 in a particular series group are electrically connected in series.

[0056] As with the first embodiment, in the second embodiment the respective anodes 42 and cathodes 44 of the OLED modules 38 electrically connected in series are typically connected via interconnect wiring 46 .

[0057] In one embodiment of the present invention, power is provided to the series groups 36 and thus the individual OLED modules 38 from the power source 32 via a first conducting line 48 and a second conducting line 50 . The first conducting line 48 is electrically connected to a first end of each OLED series group 36 . The second conducting line 50 is electrically connected to a second end of each OLED series group 36 opposite the first end. The first end and second end of each OLED series group 36 are opposite to each other in the sense of having opposite polarity, i.e., one of the ends is electrically connected to the cathode 44 and the other end is electrically connected to an anode 42 . The first end and second end need not be opposite to each other in a spatial sense, i.e., the first end and second end need not correspond to the OLED modules 38 that are physically the furthest apart.

[0058] FIG. 2 shows the power source 32 as being separate from the light emitting device 30 . In another embodiment of the present invention, the power source 32 is included in the light emitting device 30 .

[0059] In another embodiment of the present invention, the light emitting device 30 further comprises a plurality of circuit elements 52 . Each circuit element 52 is electrically connected in parallel with a respective OLED module 38 . In this case, each OLED module 38 does not have a corresponding circuit element 52 . However, if the light emitting device 30 includes circuit elements 52 , at least some of the OLED modules 38 have a corresponding circuit element 52 .

[0060] FIG. 2 shows each of the circuit elements 52 in parallel with a single OLED module 38 . In another embodiment of the present invention, a particular circuit element 52 is in parallel with more than one OLED module 38 .

[0061] In another embodiment of the present invention, the circuit elements 52 are selected from the group consisting of resistors, diodes, varistors, and combinations thereof. The circuit element 52 functions to modify the voltage across its respective OLED module 38 . In another embodiment of the present invention, the circuit element 52 reduces the voltage across its respective OLED module 38 to provide a proper operating voltage for the OLED module 38 .

[0062] In another embodiment of the present invention, the circuit element 52 functions to provide fault tolerance for its respective OLED module 38 . The circuit element 52 is selected from the group consisting of a diode, a varistor, a resistor, and any combination thereof.

[0063] In another embodiment of the present invention, the series groups 36 of the light emitting device 30 is arranged such that the ends of the series groups 36 that are connected to the first conducting line 48 have alternating polarity as shown in FIG. 2 . In this embodiment, the first conducting line 48 is electrically connected to one series group via the cathode 44 of the OLED module 38 of that series group 36 , and the next series group 36 is electrically connected to the first conducting line 48 via an anode 42 of the OLED module 38 of that next series group 36 . Likewise, the second conducting line 50 is connected to the end of the series group 36 having alternating polarity. In one embodiment of the present invention, DC power is supplied to the voltage supply 32 and the first conducting line 48 is connected to the positive side of the voltage supply 32 , and the second conducting line 50 is connected to the negative side of the voltage supply 32 , then the OLED series group 36 disposed in between the other OLED series groups 36 does not illuminate. In another embodiment of the present invention, DC power is supplied to the voltage supply 32 and the first conducting line 48 is connected to the negative side of the voltage supply 32 , and the second conducting line 50 is connected to the positive side of the voltage supply 32 , then the OLED series groups 36 disposed above and below the OLED series group 36 disposed in the middle do not illuminate.

[0064] When AC power is provided to the light emitting device 30 , and the series groups 36 are arranged to be connected with alternating polarity, the fraction of the series groups 36 connected with one polarity emits light during one half-cycle of the AC waveform. During the other half-cycle, the remaining series groups 36 connected with the opposite polarity emits light. Thus, the light emitted during both half-cycles of the AC waveform has temporal uniformity.

[0065] When using AC power and it is desired that the light emitted during both half cycles be of the same overall intensity, then one-half of the OLED modules 38 of the series groups 36 are connected with one polarity and one-half of the OLED modules 38 of the series groups 36 are connected with the other polarity. When using AC power in an application that does not require that the light emitted during alternating half-cycles have a uniform temporal intensity, then the fraction of OLED modules 38 connected with one polarity need not be the same as the fraction connected with the opposite polarity. In another embodiment of the present invention, the OLED modules 38 are connected with the same polarity as shown in FIG. 5 .

[0066] FIG. 2 illustrates an embodiment of the present invention where the series groups 36 that are immediately adjacent to one another are connected to have opposite polarity. The light emitting device in this arrangement emits light with a uniform spatial intensity. In another embodiment of the present invention, the series groups 36 are be arranged such that immediately adjacent series groups have the same polarity.

[0067] FIG. 2 illustrates each of the series groups 36 comprising a row of OLED modules 38 where the OLED modules in the group are arranged in a straight line. In another embodiment of the present invention, the series groups 36 comprise a group of OLED modules 38 arranged in a configuration other than a straight line. In this embodiment, the group of OLED modules 38 corresponding to a particular series groups 36 are arranged in more than one straight line of OLED modules 38 . In another embodiment of the present invention (not shown in FIG. 2 ), the group of OLED modules 38 corresponding to a particular series groups 36 are arranged so that only a fraction of the OLED modules 38 are in one particular line.

[0068] FIG. 2 illustrates each of the series groups 36 having four OLED modules 38 . However, the number of OLED modules 38 is not limited to four, and the actual number of OLED modules 38 are left to the artisan to determine. The number of OLED modules 38 will depend upon the maximum desired voltage for an OLED module 38 , and upon the maximum voltage provided by the power source 32 at the peak of the AC voltage waveform used in operation. For example, when a 120V source 32 is employed and each OLED module 38 has an identical current/voltage characteristic with a maximum desired voltage of 10V, then twelve OLED modules 38 are connected in series. Alternatively, if circuit elements 52 are employed to reduce the voltage to respective OLED modules 38 by one-third, eight OLED modules 38 are employed in each series group 36 . In this case, the circuit elements 52 are disposed in series with the OLED modules 38 . The details of the circuit elements 52 are as discussed above.

[0069] FIG. 3 illustrates an embodiment of the invention where the OLED modules 38 of a particular series group 36 of a light emitting device 60 are arranged as part of a sign to spell out a word or depict an image. As with the second embodiment, in the embodiment of FIG. 3 , the light emitting device 60 comprises the plurality of series groups 36 , each series group 36 comprising the plurality of OLED modules 38 . Also, as with the second embodiment, in the embodiment of FIG. 3 , the OLED modules 38 , each having an anode 42 and cathode 44 , of a particular series group are electrically connected in series, i.e., anode 42 to cathode 44 . When the voltage is provided from the power source 32 to the OLED modules 38 , the OLED modules 38 emit light.

[0070] As used herein, the light emitting device 60 of FIGS. 3 and 61 of FIG. 4 also refers to a display 60 where at least one OLED module 38 is disposed to depict at least one of the group consisting of letters, numbers, images, and any combination thereof.

[0071] Power is provided to the series groups 36 and thus the individual OLED modules 38 are coupled to the power source 32 (either separate from or part of the light emitting device 60 ). The power is provided via first conducting line 48 and second conducting line 50 . The first conducting line 48 is electrically connected to a first end of each OLED series group 36 . The second conducting line 50 is electrically connected to a second end of each OLED series group 36 opposite the first end.

[0072] The OLED modules 38 collectively spell out the letters “S” and “T” in FIG. 3 . It is left to the artisan to determine how the OLED modules 38 are arranged to spell out any text, present any numbers, or depict any images. In one embodiment of the present invention, individual letters, numbers or images are presented using more than one series group 36 and in a more specific embodiment of the present invention individual letters, numbers, or images are presented in all a single series group 36 . In another embodiment of the present invention, individual letters, numbers, or images are presented using a part of a single series group 36 .

[0073] FIG. 3 illustrates the OLED modules 38 arranged to spell out letters or depict images where the OLED modules 38 are arranged in a series group 36 of connected OLED modules 38 . Alternatively, in another embodiment (not shown in FIG. 3 ), the OLED modules 38 are arranged in parallel with respect to each other.

[0074] The embodiment of FIG. 3 , whether powered by a DC power source or an AC power source, provides an advantage over display or sign systems that comprise a light source and a covering sheet to block some of the light from the source to depict an image. In the embodiment of FIG. 3 , no covering sheet is required. Furthermore, the system of FIG. 3 need include only the number of OLED modules 38 necessary to depict an image, number or image, and not a full array. Thus, a cost saving is potentially achieved.

[0075] FIG. 4 shows another embodiment of the invention similar to that of FIG. 3 . However, in the embodiment of FIG. 4, a single OLED module 38 is shaped like a letter, number, or a desired image as determined by the artisan. As with the embodiment of FIG. 3, a light emitting device 61 of the embodiment of FIG. 4 comprises the plurality of series groups 36 , each series group comprising the plurality of OLED modules 38 . However, in the embodiment of FIG. 4 , each of the OLED modules 38 is shaped like a letter, number, or image. In the embodiment of FIG. 4 , the OLED modules 38 , each having an anode 42 and cathode 44 , of a particular series group 36 are electrically connected in series, i.e., anode 42 to cathode 44 . When the voltage is provided from the power source 32 to the OLED modules 38 , the OLED modules 38 emit light.

[0076] Power is provided to the series groups 36 and thus the individual OLED modules 38 from the power source 32 (either separate from or part of the light emitting device). The power is provided via the first conducting line 48 and the second conducting line 50 . The first conducting line 48 is electrically connected to the first end of each OLED series group 36 . The second conducting line 50 is electrically connected to the second end of each OLED series group 36 opposite the first end.

[0077] The three OLED series groups in FIG. 4 , respectively spell out the words “EAT”, “AT”, and “JOES”. The artisan is left to determine how to arrange the OLED modules to depict any letters, number, and images desired.

[0078] FIG. 4 illustrates the OLED modules 38 arranged to depict letters, numbers, and images where the OLED modules 38 are arranged in series group 36 of connected OLED modules 38 . In another embodiment of the present invention, the OLED modules 38 are connected in parallel with each other.

[0079] FIG. 5 shows another embodiment of the invention. The embodiment of FIG. 5 is the same as that of the second embodiment, except that a light emitting device 70 of FIG. 5 includes the converting circuit 52 . The middle series group 36 as depicted in FIG. 5 is connected between the first conducting line 48 and the second conducting line 50 in the same polarity configuration compared to the top and bottom series groups 36 . The other portions of the description of the embodiment of FIG. 5 are the same as that of the second embodiment ( FIG. 2 ), and are omitted here for the sake of brevity.

[0080] The converting circuit 72 is connected to both the power source 32 , and the first conducting line 48 and second conducting line 50 . In an embodiment utilizing the AC power source, the converting circuit 72 acts to convert the voltage waveform applied by the power source 32 to a converted voltage waveform. The converted voltage waveform is then applied to the series group modules 36 . An example of the converting circuit 72 , as shown in FIG. 6 , is described below.

[0081] FIG. 9 shows a sinusoidal voltage waveform output from the AC power source, such as a line voltage. In applications where a square pulse waveform is desired, the converting circuit acts to convert the sinusoidal voltage waveform to a square pulse waveform, such as the one shown in FIG. 10 . In one embodiment of the present invention, a square pulse waveform is utilized for applications where the OLED modules 38 operate at their highest efficiency at a particular voltage. The voltage magnitude of the square pulse is set to be at about the highest efficiency voltage in that case. Thus, the converting circuit 72 acts to provide a converted waveform so that the optimum voltage is applied across the OLED modules.

[0082] FIG. 10 shows a square wave pulse waveform where the length of time that the voltage is positive is approximately the same as the length of time that the voltage is positive, i.e., the period for positive voltage is the same as the period for negative voltage. However, in another embodiment of the present invention, the voltage waveform has a length of time that voltage is negative that is greater than the length of time that the voltage is positive. In another embodiment of the present invention, the voltage waveform utilized has a length of time that voltage is negative that is less than the length of time that the voltage is positive.

[0083] Referring again to FIG. 5 , the converting circuit 72 in one embodiment of the present invention comprises, for example, back-to-back zener diodes. FIG. 6 shows an example of the converting circuit 72 with back-to-back zener diodes, 400 and 402 , respectively. The zener diodes 400 and 402 are connected to the power source 32 with opposite polarity, as provided in FIG. 6 . The zener diodes 400 and 402 are chosen so that the rating clamping voltage provided by the zener diodes 400 and 402 would provide a voltage to the OLED modules 38 that is close to the optimum operating voltage. Zener diodes 400 and 402 are typically not manufactured with a tight tolerance with regards to clamping voltage. Therefore, the voltage provided by the converting circuit 72 comprising back-to-back zener diodes 400 and 402 is typically a “clipped” sine wave waveform (assuming the input waveform is sinusoidal), not a true square wave. However, the “clipped” sine wave is typically sufficient in most applications, and a back-to-back zener diodes 400 and 402 converting circuit is typically cost effective.

[0084] The frequency of the voltage waveform output from the zener diode converting circuit 72 has the same frequency as the input waveform. In another embodiment of the present invention, the converting circuit 72 is constructed to provide a square wave pulse that is driven at a significantly higher frequency, i.e., >10 kHz, than cycle frequency input into the circuit. The drive frequency selected is dictated by the response time of the light emitting device 70 .

[0085] FIG. 7 shows another embodiment of the invention. The embodiment of FIG. 7 is the same as that of embodiment of FIG. 5 except that the converting circuit 72 has outputs for three conducting lines, two first conducting lines 48 and 51 , and the second conducting line 50 . Thus, the portion of the description of the embodiment of FIG. 7 that is the same as that of the embodiment of FIG. 5 is omitted here for the sake of brevity.

[0086] FIG. 8 shows another example of the converting circuit 72 that is used in the light emitting device 70 of FIG. 7 . FIG. 8 provides a wave pulse that is typically driven at a higher frequency than the cycle frequency input into the circuit. The converting circuit 72 includes a rectifier and filter device 410 , where the rectifier and filter device 410 are connected to the AC power source 32 . The converting circuit 72 also includes two transistors 412 and 414 connected to each other at node 416 as shown in FIG. 8 . The transistor 412 is also connected to one terminal of the rectifier and filter 410 , while the other transistor 414 is connected to the other terminal of the rectifier and filter 410 . The converting circuit 72 also includes a crystal oscillator 418 , where one terminal of the crystal oscillator 418 is connected to one transistor 412 , and the other terminal of the crystal oscillator 418 is connected to the other transistor 414 . The crystal oscillator 418 determines the driving frequency of the waveform input to the OLED modules 38 via the lines 48 , 50 , and 51 .

[0087] The transistors of the converting circuit 72 are selected from the group consisting of field effect transistors (FETS), complementary FETS (i.e. N and P channel FETS together), and combinations thereof. The use of FETS allows miniaturization of the light emitting device package. Additionally, the use of complementary FETS further reduces the package size. With minimal rectification of the input line voltage for cost effectiveness, the square wave pulse would necessarily have a modulation. However, it is believed that this would have an imperceptible effect on the light output.

[0088] A method of operating the light emitting device of the present invention is now described. In the simplest form, the light emitting device 10 of FIG. 1 is operated by applying the voltage to the OLED modules 12 . When using the AC power supply, a sinusoidal waveform line voltage is applied to one of the light emitting devices 10 , 30 of FIG. 2, 60 of FIG. 3 , and 61 of FIG. 4 , and thus a sinusoidal waveform is applied to the OLED modules 12 of FIG. 1, 38 of FIG. 2, 38 of FIG. 3 , and 38 of FIG. 4 , respectively.

[0089] In another embodiment of the present invention, the AC waveform other than a sinusoidal wave form is applied to one of the light emitting devices 10 of FIG. 1, 30 of FIG. 2, 60 of FIG. 3 , and 61 of FIG. 4 . In a specific embodiment of the present invention, a square pulse voltage waveform is applied to one of the light emitting devices 10 of FIG. 1, 30 of FIG. 2, 60 of FIG. 3 , and 61 of FIG. 4 . Therefore, the square pulse voltage waveform is applied to the OLED modules 12 of FIG. 1, 38 of FIG. 2, 38 of FIG. 3 , and 38 of FIG. 4 , respectively.

[0090] In another alternative embodiment of the present invention, the sinusoidal AC waveform is applied to the light emitting device depicted in FIG. 5 or FIG. 7 , and the sinusoidal waveform is then transformed to another waveform on the light emitting device itself. In this case, the device transformed waveform, such as a square pulse waveform, or “clipped” sine wave waveform, is then provided to the OLED modules 38 .

[0091] FIGS. 11 and 12 show a side view and top view of another embodiment of the present invention. In FIG. 11, a light emitting device 300 includes a substrate 301 . The substrate 301 is typically a glass or some other transparent substrate. A first OLED module 303 and a second OLED module 305 are disposed adjacent to one another. Collectively a first electrode 302 , an interconnect 304 , a second electrode 306 , and a light emitting layer 308 form the first OLED module 303 and the second OLED module 305 . The interconnect 304 provides electric connection between the first electrode 302 of first OLED module 303 and the respective second electrode (cathode) 306 of second OLED 305 . The first electrode (anode) 302 of the first OLED module 303 is disposed on a first portion 320 of the substrate 301 . The first electrode (anode) 302 of the second OLED module 305 is disposed on the first portion 320 of the substrate 301 . The interconnect 304 is disposed on a portion of the first electrode 302 of the first OLED module 303 and a fourth portion 326 of the substrate 301 . The interconnect 304 is disposed on the portion of the first electrode 302 of the second OLED module 305 and the fourth portion 326 of the substrate 301 . The light emitting layer 308 is disposed over a second portion 322 of the substrate 301 , a portion of the first electrode 302 of the first OLED module 303 , and a portion of the interconnect 304 of the first OLED module 303 . The second electrode 306 is disposed on a third portion 324 of the substrate 301 , a portion of the light emitting layer 308 of the first OLED module 303 , and a portion of the interconnect 304 of the second OLED module 305 . The first electrode 302 is typically optically transparent to allow light from the light emitting layer 308 to pass through the first electrode 302 .

[0092] In one embodiment of the present invention, the first OLED module 303 and second OLED module 305 are connected in series. In another embodiment of the present invention, the first OLED module 303 and second OLED module 305 are connected in parallel.

[0093] As used herein, the terms “disposed on”, “disposed from”, “disposed to”, “disposed over”, “disposed above”, “disposed between” and the like are used to refer to relative locations of items illustrated in the drawings and do not imply structural or operational limitations in the assembled device.

[0094] As seen in FIG. 12 , groups of OLED modules 303 , 305 are connected in series to form series groups 310 . The opposing end electrodes of the series groups 310 are electrically connected, respectively to a first conducting line 312 and a second conducting line 314 . Preferably, the two series groups 310 are arranged such that the electrode of one of the series groups that is connected to the first conducting line 312 , has the opposite polarity of the electrode of the other series group that is connected to the first conducting line 312 . The first conducting line 312 and the second conducting line 314 are configured to be coupled to the external power source.

[0095] A method of making the light emitting device of FIG. 11 according to the present invention is now described with respect to FIG. 13 . The light emitting device 300 comprises the plurality of OLED modules 303 , 305 . The plurality of OLED modules 303 , 305 further comprises at least the first OLED module 303 and the second OLED module 305 . In step 1 of FIG. 13 , the method comprises disposing a respective first electrode 302 of each OLED module 38 on a respective portion of the substrate 301 . In step 2 , the method further comprises disposing the first electrode 302 of the first OLED module 303 on a first portion 320 of the substrate 301 . The interconnect 304 is disposed on a portion of the first electrode 302 of the first OLED module 303 and a fourth portion 326 of the substrate 301 . In step 3 , the light emitting layer 308 is disposed on a second portion 322 of the substrate 301 , a portion of the first electrode 302 , and a portion of the interconnect 304 . In step 4 , the second electrode 306 is disposed over a third portion 324 of the substrate 301 , a portion of the light emitting layer 308 , and a portion of the interconnect 304 of the second OLED module 305 . The second OLED module 305 is disposed adjacent to the first OLED module 303 .

[0096] FIGS. 14 and 15 show a side view and top view of another embodiment of the present invention. In FIG. 14 , the light emitting device 300 includes the substrate 301 . The first electrode 302 of the first OLED module 303 is disposed on the first portion 320 of the first OLED module 303 . The light emitting layer 308 is disposed on the second portion 322 of the substrate 301 and a portion of the first electrode 302 of the first OLED module 303 . The second electrode 306 is disposed over a third portion 324 of the substrate 301 , a portion of the light emitting layer 308 , and a portion of the first electrode 302 of the second OLED module 305 . The first OLED module 303 and the second OLED module 305 are disposed adjacent to one another. In one embodiment of the present invention, the first OLED module 303 and second OLED module 305 are connected in series.

[0097] As seen in FIG. 15 , groups of first OLED modules 303 and second OLED modules 305 are connected in series to form series groups 310 . The opposing end electrodes of the series groups 310 are electrically connected, respectively to the first conducting line 312 and the second conducting line 314 . In one embodiment of the present invention, the two series groups 310 are arranged such that the electrode of one of the series groups that is connected to the first conducting line 312 , has the opposite polarity of the electrode of the other series group that is connected to the first conducting line 312 . In one embodiment of the present invention, the first conducting line 312 and the second conducting line 314 are configured to be coupled to the external power source (not shown in FIG. 15 ).

[0098] Another method of making the light emitting device of FIG. 14 according another embodiment of the present invention is now described with respect to FIG. 16 . The light emitting device 300 comprises the plurality of OLED modules 303 , 305 . The plurality of OLED modules 303 , 305 further comprises at least the first OLED module 303 and the second OLED module 305 . The method comprises disposing a respective first electrode 302 of each OLED module 38 on a respective portion of a substrate 301 . In step 1 , the method comprises forming the first OLED module 303 by disposing the first electrode 302 of the first OLED module 303 on the first portion 320 of the substrate 301 . In step 2 , the method further comprises disposing the light emitting layer 308 on a second portion 322 of the substrate 301 and a portion of the first electrode 302 of the first OLED module 303 . In step 3 , the method further comprises disposing the second electrode 306 over a third portion 324 of the substrate 301 , a portion of the light emitting layer 308 , and a portion of the first electrode 302 of the second OLED module 305 . The second OLED module 305 is disposed adjacent to the first OLED module 303 .

[0099] FIGS. 17 and 18 show a side view and top view of another embodiment of the present invention. In FIG. 17 , the light emitting device 300 includes the substrate 301 . The first electrode 302 of the first OLED module 303 is disposed on the first portion 320 of the substrate 301 . The light emitting layer 308 is disposed on a portion of the first electrode 302 of the first OLED module 303 . The light emitting layer 308 is further disposed on a portion of the first electrode 302 of the second OLED module 305 and the second portion 322 of the substrate 301 . The second electrode 306 is disposed on the portion of the light emitting layer 308 of the first OLED module 303 , a portion of the light emitting layer 308 of the second OLED module 305 , and a portion of the first electrode 302 of the first OLED module 303 . The first OLED module 303 and the second OLED module 305 are disposed adjacent to one another. In one embodiment of the present invention, the first OLED module 303 and second OLED module 305 are connected in series.

[0100] As seen in FIG. 18 , groups of OLED modules 303 , 305 are connected in series to form series groups 310 . The opposing end electrodes of the series groups 310 are electrically connected, respectively to the first conducting line 312 and the second conducting line 314 . In one embodiment of the present invention, the two series groups 310 are arranged such that first electrode 302 of one of the series groups 310 that is connected to the first conducting line 312 , has the opposite polarity of the second electrode 306 of the other series group 310 that is connected to the first conducting line 312 . The first conducting line 312 and the second conducting line 314 are configured to be coupled to the external power source (not shown in FIG. 18 ).

[0101] Another method of making the light emitting device of FIG. 17 according to the present invention is now described with respect to FIG. 19 . The light emitting device 300 comprises the plurality of OLED modules 303 , 305 . The plurality of OLED modules 303 , 305 further comprises at least the first OLED module 303 and the second OLED module 305 . The method in step 1 comprises disposing the respective first electrode 302 of each OLED module 303 , 305 on a respective portion of the substrate 301 . In step 1 , the method further comprises disposing the first electrode 302 of the first OLED module 303 on a first portion 320 of the substrate 301 . In step 2 of the method, the light emitting layer 308 is disposed on a portion of the first electrode 302 of the first OLED module 303 , a portion of the first electrode 302 of the second OLED module 305 and the second portion 322 of the substrate 301 . In step 3 of the method, the second electrode 306 is disposed on the portion of the light emitting layer 308 of the first OLED module 303 , a portion of the light emitting layer 308 of the second OLED module 305 , and a portion of the first electrode 302 of the first OLED module 303 . The second OLED module 305 is disposed adjacent to the first OLED module 303 .

[0102] In another method embodiment of the present invention, a first conducting material 340 is deposited over the substrate 301 as shown in Step 1 of FIG. 20 . In one method embodiment of the present invention, the first conducting material 340 is patterned to form the plurality of first electrodes 302 as depicted in Step 2 . In another more specific embodiment of the present invention, the first conducting material is disposed onto the first portion 320 of the substrate 301 to form the plurality of first electrodes 302 . In another specific embodiment of the present invention, a first conducting interconnect material 380 is disposed over the plurality of first electrodes 302 and a portion of the substrate 301 in Step 3 . The first conducting interconnect material 380 is patterned to form a plurality of interconnects 304 in Step 4 .

[0103] In Step 5 of FIG. 20 the light emitting material 350 is disposed on the interconnects 304 , a portion of the substrate 301 , and a portion of the first electrodes 302 . In Step 6 , the light emitting material 350 is patterned to form the light emitting layer 308 . In one embodiment of the present invention, the light emitting layer 308 is disposed on the second portion 322 of the substrate 301 , a portion of the first electrode 302 , and a portion of the interconnect 304 . In one embodiment of the present invention, the light emitting layer 308 is formed by evaporating a light emitting material 350 through a shadow mask where the light emitting layer is disposed in electrical contact with the first conducting electrode 302 . In another embodiment of the present invention, the light emitting layer 308 is formed by depositing the light emitting material 350 over the substrate 301 , for example by a spin-on process. In one embodiment of the present invention, the light emitting layer 308 is formed by etching the deposited light emitting material 350 with an appropriate etchant. In one embodiment of the present invention, the light emitting layer 308 is formed by laser ablation of selected portions of the deposited light emitting material 350 .

[0104] In Step 7 of FIG. 20 , the second electrode material 360 is disposed over the third portion 324 of the substrate 301 , the light emitting layer 308 , and a portion of the interconnect 304 . In step 8 , the second electrode material 360 is patterned to form the plurality of second electrodes 306 . In one method embodiment of the present invention, the second electrode 306 is disposed over the third portion 324 of the substrate 301 , and the second electrode 306 is disposed on a portion of the light emitting layer 308 and a portion of the interconnect 304 of the adjacent second OLED module 305 .

[0105] Another method embodiment of the present invention is provided in FIG. 21 , where the first conducting material 340 is deposited over the substrate 301 in step 1 and the first conducting material 340 is patterned to form the plurality of first electrodes 302 in Step 2 . Steps 1 and 2 of FIG. 21 are similar to the Steps 1 and 2 of FIG. 20 as described above. In another specific embodiment of the present invention, the light emitting material 350 of FIG. 21 is disposed over the plurality of first electrodes 302 , the second portion 322 of the substrate 301 , and the third portion 324 of the substrate 301 in step 3 . In step 4 , the light emitting material 350 is patterned to form the light emitting layer 308 . In one embodiment of the present invention, the light emitting layer 308 is disposed on a portion of the respective first electrode 302 and the second portion 322 of the substrate 301 .

[0106] In step 5 of FIG. 21 the second electrode material 360 is disposed over the third portion 324 of the substrate 301 , a portion of the light emitting layer 308 , and a portion of the first electrode 302 . In Step 6 , the second electrode material 360 is patterned to form the plurality of second electrodes 306 . In one method embodiment of the present invention, the second electrode 306 of FIG. 14 is disposed on the third portion 324 of the substrate 301 , a portion of the light emitting layer 308 , and a portion of the first electrode 320 of the adjacent second OLED module 305 .

[0107] In one embodiment of the present invention, the first conducting electrode material 340 of FIG. 21 and the plurality of first electrodes 302 comprises at least one conducting transparent material such as indium tin oxide (ITO), tin oxide, nickel, or gold. In one embodiment of the present invention, the first conducting interconnect material 380 of FIG. 20 is selected from the group consisting of copper, aluminum, titanium, a