JP5527817B2 - Repair method - Google Patents

Description

  The present invention relates to a method for repairing a surface light emitting device.

  As a new light emitter, an EL (Electro Luminescence) element which is a surface light emitting element is becoming widespread. In addition, surface light emitting devices using EL elements have been studied and commercialized as thin and large displays replacing liquid crystal displays and plasma displays.

  Furthermore, the light emitted from the EL element is close to natural light because of its broad emission spectrum. Therefore, a surface light emitting device using an EL element is also suitable for use as a lighting device.

  In a surface light emitting device using an EL element, one or a plurality of EL elements are provided on one surface of a transparent substrate. The EL element has a configuration in which a light-transmitting anode (transparent electrode), an organic layer, and a cathode (metal electrode) are sequentially laminated from the transparent substrate side.

  In a very small area of the EL element of this surface light emitting device, there are many defects that the anode and the cathode are short-circuited and a part or all of the surface light emitting device does not emit light. Therefore, the yield was low.

  One cause of this short circuit is that foreign matter such as dust adheres to the substrate during the manufacture of the EL element, and the anode and the cathode are short-circuited through the foreign matter.

  Therefore, as a method of repairing the short-circuited surface light emitting device, a method of irradiating the short circuit portion of the EL element of the surface light emitting device with laser, destroying the short circuit portion, and repairing so that the portions other than the short circuit portion normally emit light. (For example, Patent Document 1).

JP 2009-277528 A

  In the case of a display device using a surface light emitting device, a plurality of EL elements are used, and since EL elements are used for each pixel, even if a short circuit occurs in one EL element, one pixel is not lit. Therefore, the display device is not disabled. However, in the case of a lighting device using a surface light emitting device, there is one EL element used in the surface light emitting device. Therefore, when a short circuit occurs in the EL element, the entire surface light emitting device does not emit light, and the lighting device does not perform its function. When repairing a short-circuited lighting device, if the laser is irradiated in accordance with the size of the short-circuit portion, the short-circuit portion may not be completely destroyed due to problems such as irradiation accuracy. The surface light-emitting device used for the lighting device cannot emit light unless all the short-circuit portions are destroyed. Therefore, in order to reliably destroy the short-circuit portion with the laser, the laser is irradiated to a range larger than the short-circuit portion of the EL element, and the short-circuit portion and its surroundings are destroyed at the same time. As a result, repair was performed so as to ensure light emission except for the short-circuited portion and its surroundings.

  However, the portion of the EL element destroyed by the laser (hereinafter referred to as “correcting portion”) does not always emit light, and becomes a dark spot when the surface emitting device emits light. Therefore, when repairing an illuminating device using a surface light emitting device, when the illuminating device is caused to emit light, the vicinity of the boundary between the light emitting portion that can emit light and the corrected portion that is destroyed by the laser of the EL element The brightness changes abruptly. Accordingly, a binary state of light and dark is obtained near this boundary (see FIG. 9). In such a binary state, the contour of the correction part is easily recognized by the user, and the dark spot becomes conspicuous.

  The objective of this invention provides the repair method which solves the subject that the part destroyed with the laser at the time of light emission of the repaired surface emitting device becomes conspicuous as a dark spot.

  A surface light-emitting device comprising: a transparent substrate; an anode laminated on the transparent substrate; a cathode facing the transparent electrode; and a surface light-emitting element having an organic layer sandwiched between the anode and the cathode. Irradiate a laser to the short-circuited part of. Then, as the distance from the correction portion of the surface light emitting element formed by laser irradiation increases, a plurality of gradations are provided in brightness.

  According to the present invention, when the repaired surface light emitting device emits light, the change in brightness near the boundary between the light emitting part and the part destroyed by the laser becomes gentle, and the dark spot becomes inconspicuous.

It is the schematic which shows one Embodiment of the repair method which concerns on this invention, (a) is the schematic explaining the recognition method of the short circuit part using the schematic of the AA cross section of FIG. 3, (b) is a figure 3 is a schematic view of a BB cross section of FIG. It is the schematic which shows one Embodiment of the repair method which concerns on this invention, (a) is the schematic explaining the laser irradiation method to the short circuit part using the schematic of the XX cross section of FIG. 4, (b) is FIG. 5 is a schematic view of a YY section in FIG. 4. It is the schematic which looked at the illuminating device of the state which short-circuited from the transparent substrate side. It is the schematic which looked at the illuminating device after laser irradiation from the transparent substrate side. It is a figure which shows the position of a halftone dot when making the diameter of a halftone dot constant. It is a figure which shows the magnitude | size and position of the diameter of a halftone dot when changing the diameter of a halftone dot. It is a figure which shows the pattern of the gradation which can be expressed with a matrix structure. It is a figure which shows the correction part when the repair method of this invention is applied, and the change of the brightness of the circumference | surroundings. It is a figure which shows a correction part when the related art repair method is applied, and the change of the brightness of the circumference | surroundings.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same number is attached | subjected to the structure which has the same function in an accompanying drawing, and the description may be abbreviate | omitted.

  A method for repairing a surface light emitting device according to the present invention will be described below. In the following description, a lighting device using a surface light emitting device using a surface light emitting element will be described as an example.

  FIG. 1 is a schematic diagram illustrating an embodiment of a repair method according to the present invention, and FIG. 1A is a schematic diagram illustrating a method for recognizing a short circuit using the schematic diagram of the AA cross section of FIG. ) Is a schematic view of the BB cross section of FIG. 3. FIG. 2 is a schematic diagram illustrating an embodiment of the repair method according to the present invention, and (a) is a schematic diagram illustrating a laser irradiation method to a short-circuit portion using the schematic diagram of the XX cross section of FIG. (B) is the schematic of the YY cross section of FIG. 3 is a schematic view of the illuminating device in a short-circuited state as seen from the transparent substrate side, and FIG. 4 is a schematic view of the illuminating device after laser irradiation as seen from the transparent substrate side.

  The surface light emitting device includes a transparent substrate 1 and an EL element 7 which is a surface light emitting element provided on one surface of the transparent substrate 1. The EL element 7 is configured by a laminated body in which an anode (transparent electrode) 2, an organic layer 4, and a cathode (metal electrode) 6 are sequentially laminated on one surface of the transparent substrate 1. The transparent substrate 1 is made of glass, for example. The transparent electrode serving as the anode 2 is made of, for example, ITO (Indium Tin Oxide) having high light transmittance. The metal electrode which becomes the cathode 6 is mainly composed of aluminum. The organic layer 4 is an EL (Electro-Luminescence) layer made of an organic material.

  The formation method of the organic layer 4 is not limited as long as a light emitting material is used, but a hole transport layer may be provided on the anode 2 side of the organic layer 4 and an electron transport layer may be provided on the cathode 6 side. Further, a hole injection layer may be provided between the anode 2 and the hole transport layer, and an electron injection layer may be provided between the cathode 6 and the electron transport layer. You may change the structure of the organic layer 4 further as needed. For example, the electron injection layer may be an oxide or fluoride of an alkali metal or alkaline earth metal.

  The illumination device having the surface light emitting device is further provided on the side of the transparent substrate 1 on which the EL element 7 is provided, and a sealing substrate 8 is provided at a position spaced from the cathode 6. A sealing member 9 is provided between the end of the transparent substrate 1 and the transparent substrate 1 having the anode 2 and the cathode 6. The EL element 7 is positioned inside a region surrounded by the transparent substrate 1, the sealing substrate 8, and the seal member 9. Further, by integrating a converter circuit, an inverter circuit, a lighting circuit, and the like (not shown) on the sealing substrate 8, a lighting device that is easy to handle can be obtained.

  The light emission principle of the EL element 7 will be described. The end of the anode 2 and the end of the cathode 6 are connected to a power supply unit having the above circuit via an FPC (Flexible Printed Circuits), a cable line, or the like not shown here. A voltage is applied to the anode 2 and the cathode 6 by the power supply unit, and holes are injected from the anode 2 to the organic layer 4 and electrons are injected from the cathode 6 to the organic layer 4 by the electric field. The injected holes and electrons are recombined in the light emitting material in the organic layer 4 to form excitons and enter an excited state. Light emission occurs when returning from an excited state to a low level or a ground state. The emitted light passes through the transparent substrate 1 and is emitted to the outside.

  The repair device used in the repair method of the present invention has a repair head and a stage. The repair head includes an image recognition device 10 that is an inspection optical system that recognizes the short-circuit portion 15 of the EL element 7 and a laser irradiation device 11 that destroys the short-circuit portion 15 of the EL element 7. The illumination device is disposed on the stage. The stage on which the illumination device is arranged may be moved with respect to the repair head, or the repair head may be moved with respect to the stage. In FIGS. 1A and 2A, only the image recognition device 10 and the laser irradiation device 11 are illustrated.

  Next, the recognition method of the short circuit part 15 is demonstrated using FIG. 1 and FIG.

  As shown in FIGS. 1 and 3, there is a case where foreign matters are mixed in the EL element 7 and the anode 2 and the cathode 6 are short-circuited. First, the image recognition device 10 specifies the presence / absence of a portion (short-circuit portion) 15 that has caused a short circuit and the position thereof. Normally, the short-circuit portion 15 formed of foreign matter or the like has the cathode 6 around the foreign matter or the like as a center and is peeled off by heat due to current concentration. For this reason, since the reflectance from external light differs in the short circuit part 15 and the other part, it can discover easily. If the lighting device is driven with a low current density when it is not completely short-circuited, the short-circuited portion 15 that is a dark spot can be easily found because it emits light with low brightness except for the short-circuited portion 15.

  Next, a method for destroying the short-circuit portion 15 by laser irradiation will be described with reference to FIGS.

  After recognizing the short circuit part 15 by the recognition method of said short circuit part 15, the short circuit part 15 is destroyed and an illuminating device is repaired. Based on the positional information of the short-circuit part 15 specified by the image recognition apparatus 10 described above, the short-circuit part is generated using the second harmonic 532 nm or the third harmonic 355 nm of the YAG (Yttrium-Aluminum-Garnet) laser from the laser irradiation device 11. Heat is applied to 15 to destroy the short-circuit portion 15. As described above, when irradiating the laser, the laser is irradiated to a region larger than the short-circuit portion 15 so that the lighting device is reliably repaired. However, it is desirable that the region to be irradiated with laser is not so large as that of the short-circuit portion 15.

  When the illuminating device repaired in this manner emits light, the brightness changes rapidly in the vicinity of the boundary between the light emitting part that emits light and the part (corrected part) 16 that is destroyed by the laser that does not emit light and becomes a dark spot. Thus, a binary state of light and dark is obtained (see FIG. 9). As described above, when the illumination device is caused to emit light in such a state, the dark spot of the correction unit 16 is easily recognized and becomes conspicuous.

  Therefore, in the repair method of the present invention, this binary state is eliminated. Specifically, the repairing portion 16 that becomes a dark spot when the lighting device is caused to emit light by repairing is formed on the EL element 7, and the periphery of the repairing portion 16 is also irradiated with laser to emit the EL element 7. The points (spots) that are broken and insulated are provided in the form of a halftone dot that is dark in the vicinity of the correction unit 16 and becomes brighter as the distance from the correction unit 16 increases. In this way, gradation can be provided to the lightness of the correction unit 16 and its surroundings, and the lightness can be changed gently, and the correction unit 16 and its surroundings are not in a binary state of light and dark. Therefore, it becomes difficult to recognize the outline of the correction unit 16, and the correction unit 16 that becomes a dark spot becomes inconspicuous. At this time, by arranging the halftone dots so that the diffraction effect of the light emitted from between the correction portions 16 can be obtained, the recognition of dark spots can be further lowered, and the effect is further enhanced.

  The position of the halftone dot where the spot is provided will be described.

  In the vicinity of the correction unit 16, the ratio of the halftone dots to the light emitting portion is increased, and as the distance from the correction unit 16 is increased, the ratio of the halftone dots to the light emitting portion is decreased. For example, according to the normal distribution, the brightness may be changed so as to change smoothly as the distance from the vicinity of the correction unit 16 increases. For example, when making the diameter (area) of the halftone dots 20 constant, the number of halftone dots, that is, the density is changed. Specifically, the density of the halftone dots is increased in the vicinity of the correction unit 16, and As the distance increases, the density of the halftone dots is reduced (see FIG. 5, except for the central correction unit 16 which is the halftone dots 20).

  Specifically, it can be performed along smoothing that performs various weightings on the luminance distribution including the periphery of the part. For example, smoothing using a moving average filter or smoothing using a Gaussian filter can be used. As a result, extreme changes in brightness can be suppressed and smoothed, or changes in brightness can be reduced to blur the correction portion.

  In the above, the contour of a halftone dot is blurred by expressing the contrast by adjusting the position of the halftone dot, the interval between the halftone dots and the overlap, and similarly error diffusion. Various arrangements may be made using a method, a dither method using a dither matrix, or the like.

  As another example, when the diameter of the halftone dot 20, that is, the area is changed, the ratio of the halftone dot 20 to the light emitting portion is changed by changing the diameter of the halftone dot 20. Specifically, the diameter of the halftone dot is increased in the vicinity of the correction unit 16, and the diameter of the halftone dot 20 is decreased as the distance from the correction unit 16 increases (see FIG. 6, except for the central correction unit 16). is there). In this way, it is possible to add a brightness gradation around the correction unit 16.

  As another method, the portion around the correction portion 16 where the brightness is to be added is divided into a plurality of fine lattices. Then, N × N lattices are used as one matrix, and light and dark are expressed by a combination of a lattice provided with halftone dots 20 and a lattice not provided. The grid without the halftone dot 20 is bright, and the grid with the halftone dot 20 is made dark (black) by changing the size and density of the halftone dot 20. For example, in a monochrome binary image of a matrix using 2 × 2 grids, five gradations can be expressed as shown in FIG. That is, in the case of a monochrome binary image of a matrix using N × N lattices, N × N + 1 levels of gradation can be expressed by the matrix. Then, by making this matrix a gradation that matches the brightness to be expressed around the correction unit 16, a gradation of brightness is added around the correction unit 16. In the case of a grid representing black, the density of the halftone dots 20 is changed when the size of the halftone dots 20 is constant, and the diameter of the halftone dots 20 is changed when the size of the halftone dots 20 is changed. Create a grid to represent.

  The halftone dots 20 arranged as described above are irradiated with laser by the above-described repair device, and the EL element 7 is broken in accordance with the position and size of the halftone dots 20 to produce insulated spots 21.

  Since the spot 21 produced in this way can provide a gradation of brightness around the correction unit 16 when the illumination device emits light, the brightness is around the correction unit 16 as shown in FIG. It changes smoothly, and the dark spot of the correction unit 16 becomes inconspicuous. In addition, this makes it possible to use a lighting device that was previously a defective product as a non-defective product, so that the yield can be improved.

  In addition, the repair method of this invention is not limited to the illuminating device which has the EL element 7, Furthermore, it can employ | adopt irrespective of the structure of the EL element 7. FIG. For example, an EL element using a fluorescent material, an EL element using a phosphorescent material, or a hybrid EL element thereof may be used. Further, an EL element using an EL element structure having a single organic layer or a stack structure in which organic layers are stacked in multiple stages may be used.

1 Transparent substrate 2 Anode (transparent electrode)
4 Organic layer 6 Cathode (metal electrode)
7 Surface light emitting device (EL device)
8 Sealing substrate 9 Sealing member 10 Image recognition device 11 Laser irradiation device 15 Short-circuit unit 16 Correction unit 20 Halftone dot 21 spot

Claims (4)

A surface light emitting device comprising: a transparent substrate; an anode laminated on the transparent substrate; a cathode facing the anode; and a surface light emitting element having an organic layer sandwiched between the anode and the cathode. A repair method,
A method of repairing a surface light emitting element, wherein a plurality of gradations are provided in the brightness as the distance from a correction portion of the surface light emitting element formed by irradiating a laser to a short circuit portion of the surface light emitting device is increased.   The surface light emitting device repair according to claim 1, wherein a laser is irradiated around the correction portion of the surface light emitting element to form a plurality of electrically insulated spots around the correction portion of the surface light emitting element. Method.   The method of repairing a surface light emitting device according to claim 2, wherein the plurality of spots having the same diameter are provided so as to have a high density in the vicinity of the correction portion, and are provided so that the density decreases as the distance from the correction portion increases.   The surface light emitting device repair method according to claim 2, wherein the spot having a large diameter is provided in the vicinity of the correction portion, and the diameter of the spot decreases as the distance from the correction portion increases.

Images