JP2009076348A - Organic el display and its repair method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL display in which damages in repair can be reduced and which has a high reliability. <P>SOLUTION: In the organic EL display of active matrix type having a switching element and an organic EL element arranged, each organic EL element has a plurality of sub-elements, and has a current breaking portion in a non-light-emitting region between the switching element to drive the organic EL element and each sub-element. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a repairable organic EL display and a repair method thereof.

  An organic EL display in which an organic EL element in which an electron transport material, a light emitting material, a hole transport material, and the like are stacked and sandwiched between conductive materials and a switching element are arranged is widely known as a low voltage drive display. FIG. 8 is a conventional example and shows a cross-sectional view of organic EL elements arranged in an organic EL display. In the figure, 1 is a substrate having a switching element, 2 is an anode electrode, 3 is a hole transport layer, 4 is a light emitting layer, 5 is an electron transport layer, 6 is an electron injection layer, and 7 is a cathode electrode.

  In the production of an organic EL display, due to the presence of foreign matters and patterning residues, an anode electrode and a cathode electrode of an organic EL element are rarely short-circuited in a manufacturing process, and a non-lighting organic EL element that does not emit light is formed. As a method for repairing this short-circuited organic EL element, there is known a method in which an organic EL element is divided and repaired. A method for repairing a foreign matter portion in a divided organic EL element by burning it off with a laser (see Patent Document 1), or a repair method for providing a portion to be cut by excess current in the divided organic EL element (Patent Document 2) See).

JP 2000-195567 A JP 2001-319778 A

  However, when the organic EL element is repaired by cutting the short-circuit portion, damage occurs around the short-circuit portion of the organic EL element. When repairing is performed by laser irradiation or excess current in the light emitting region, there is often a problem that the reliability of the organic EL display is impaired due to damage at the time of repairing.

  An object of the present invention is to provide a highly reliable organic EL display that can reduce damage during repair and a repair method thereof.

As means for solving the above problems, the present invention provides:
In an active matrix type organic EL display in which switching elements and organic EL elements are arranged,
Each organic EL element has a plurality of sub-elements, and a current blocking portion is provided in a non-light-emitting region between the switching element that drives the organic EL element and each sub-element.

  According to the present invention, it is possible to reduce damage to an organic EL element that occurs at the time of repairing a short-circuited organic EL element and to provide a highly reliable organic EL display.

(Embodiment 1)
Embodiments of the present invention will be described below.

  1 to 3 show an example of an embodiment of the present invention.

  FIG. 1 is a top view showing a part of an organic EL display in which organic EL elements are arranged. FIG. 2 is an element cross-sectional view for explaining a method for producing an organic EL display of the present invention, and (a) to (e) in the figure show the state in the middle. FIG. 3 is a flowchart for explaining the method for repairing the non-lighted organic EL element of the present embodiment.

  1 and 2, reference numerals 101 to 104 denote anode electrodes as lower electrodes, 105 denotes a switching element, and 106 denotes a connection line between the switching element and the anode electrode. Reference numerals 107 and 108 denote a vertical wiring and a horizontal wiring, respectively, which are connected to the switching element. 109 is a cathode electrode which is an upper electrode, 110 is a contact hole formed in a flattening film, 111 is a current blocking part, 112 is a switching element, vertical wiring, horizontal wiring, and a connection line between the switching element and the anode electrode It is a substrate to be. Reference numeral 113 denotes a planarizing film, 114 denotes an insulating portion, and 115 denotes an organic vapor deposition layer.

  The organic EL display shown in FIG. 1 is an active matrix type organic EL display in which switching elements and organic EL elements are arranged, and each organic EL element has a plurality (four) of subpixels. In the present embodiment, one organic EL element emits one color, and the organic EL elements of three colors of red, green, and blue are arranged in order to form a pixel and display in full color.

  Each sub-pixel has anode electrodes 101 to 104 divided for each sub-pixel, and each anode electrode has a lead portion that is electrically connected to the connection line 106 to the switching element. Each anode electrode is divided by an insulating portion 114. At this time, the insulating portion 114 preferably has a flat surface substantially flush with the light extraction side surface of the anode electrode in the light emitting region. Irregular reflection of external light on the surface of the insulating portion 114 can be prevented.

  A connection line 106 formed in a non-light-emitting region is electrically connected to the switching element 105, and the connection line 106 has a lead portion that is electrically connected to a lead portion of the anode electrode. The lead-out portion of the connection line 106 has a width and a height that can be thermally emitted by current concentration when the connected sub-pixel is short-circuited and can be cut by a small number of laser irradiations. Is the current interrupting unit 111 in this embodiment. Note that the current blocking unit 111 is preferably formed in a contact hole region formed in the planarization film 113 covering the switching element 105. Scattered matter from the cut portion is less likely to adhere to the light emitting region, and electrical or optical problems are less likely to occur.

  In other configurations, the organic vapor-deposited layer 115 is formed on the anode electrode, and the cathode electrode 109 is further formed thereon, as in the usual organic EL display.

  Although the organic EL display having the above-described configuration will be described in detail later, the organic EL element can be repaired by short-circuiting at a current interrupting portion in a non-light emitting region, thereby reducing damage to the organic EL element that occurs and reliability It is possible to provide an organic EL display with high brightness.

  The organic EL display having the above configuration is manufactured as follows.

  First, as shown in FIG. 2A, a planarization film 113 is formed on a substrate 112 on which switching elements, vertical wirings, horizontal wirings, connection lines 106 between the switching elements and the anode electrode are formed, A contact hole 110 is formed in the planarizing film 113. The switching element 105 is connected to a vertical wiring and a horizontal wiring connected to a driving circuit outside the light emitting region. The connection line 106 between the switching element and the anode electrode is formed by laminating Cr and Al alloy simultaneously with the formation of the switching element 105. The planarizing film 113 is formed to a thickness of, for example, 0.9 microns using a photosensitive acrylic resin material. At this time, patterning is performed using a photolithography method to form the contact hole 110.

  Next, as shown in FIG. 2B, the anode electrode 101 and its lead portion are formed. The anode electrode 101 and the lead portion thereof are formed with a thickness of, for example, 0.4 microns using a sputtering method, and then formed into a desired pattern using a photolithography method and an etching method. Note that the anode electrode 101 is connected to a lead portion of the connection line 106 drawn into the contact hole 110. As described above, the lead-out portion of the connection line 106 has a width and a height that can be thermally emitted by current concentration and can be cut by a small number of laser irradiations. .

  Next, an insulating portion 114 is formed as shown in FIG. For the insulating part 114, a silicon nitride film is formed to a thickness of 0.6 microns, for example.

  Next, as shown in FIG. 2D, surface polishing is performed using abrasive particles to planarize the anode electrode 101 and the insulating portion 114. As a result, the anode electrodes 101 to 104 are configured to be divided by the insulating portion 114 having a surface substantially flush with the anode electrode in the light emitting region.

  Next, as shown in FIG.2 (e), the organic vapor deposition film 115 is formed, and also the cathode electrode 109 is formed on it. In the present embodiment, the cathode electrode 109 is formed by forming ITO with a thickness of, for example, 0.1 microns using a sputtering method. The cathode electrode 109 is formed in a stripe shape using a mask at the time of sputtering, and is connected to a driving circuit (not shown) at the periphery of the display region.

  As shown in FIG. 3, the repair method of the present invention is carried out using the organic EL display having the above configuration.

  First, the presence / absence of a non-lighting organic EL element and its position are specified from the CCD camera image data when the organic EL display is turned on in all white (step 301).

  Next, a non-lighting organic EL element is observed using a high-sensitivity CCD camera or an infrared camera, and sub-pixels that are short-circuited among the non-lighting organic EL elements are detected (step 302). At this time, the short-circuited portion of the sub-pixel that is short-circuited or the current interrupting portion whose current cross-sectional area has been reduced in advance emits light due to current concentration. In the method of estimating and repairing a subpixel short-circuited by foreign object observation, if there are a plurality of foreign objects, it is difficult to identify the shorted sub-pixel. According to the present invention, it is possible to reliably identify a short-circuited subelement among a plurality of subelements connected to a switching element that drives an organic EL element.

  When thermoluminescence at the short-circuited portion is detected, the current interrupting portion of the subelement is irradiated with a laser to be electrically disconnected and a repair process is performed (step 303).

  Next, lighting confirmation of the non-lighting organic EL element is performed, and the processing is ended (step 304). If it is not lit, the process returns to step 302 again to repair other subelements in the organic EL element.

  The organic EL display repairing method repairs an organic EL element that is short-circuited at a current blocking portion in a non-light-emitting region. Therefore, damage to the organic EL element that occurs at that time is reduced, and a highly reliable organic EL display Can be provided.

  In addition, since the switching element and each anode electrode are connected in a parallel circuit, each sub-pixel is driven with a constant current, and the repaired organic EL element is lit with brightness close to that of other organic EL elements. Can do. Therefore, a uniform organic EL display without a non-lighting organic EL element can be provided. In addition, a highly reliable organic EL display can be provided over a long period of time.

(Embodiment 2)
Next, a second embodiment of the present invention will be described.

  FIG. 4 is a cross-sectional view of an element for explaining a method for producing an organic EL display according to the present embodiment. In the figure, reference numeral 201 denotes a light emitting region, and other reference numerals are the same as those in the first embodiment.

  In this embodiment, after the insulating portion 114 is formed by sputtering, the light emitting region 201 is removed by etching using a photolithography method. Others are manufactured in the same manner as in the first embodiment.

  The organic EL display of the present embodiment can also be repaired in the same manner as in the first embodiment, and the organic EL element that is short-circuited at the current blocking portion in the non-light emitting region can be repaired. Thus, it is possible to provide a highly reliable organic EL display.

(Embodiment 3)
Next, another embodiment to which the present invention is applied will be described.

  FIG. 5 is a top view of the periphery of the contact hole where the current interrupting part is formed. In the figure, reference numeral 501 denotes a connection portion between the lead portion of the anode electrode 101 and the lead portion of the connection line 106. In the contact hole 110, the leading end of the connection line 106 is formed to be thin, and this portion serves as a current interrupting unit 111.

  In the embodiment shown in FIG. 5, the connection portion 501 that connects the anode electrode 101 and the connection line 106 is provided separately from the current interrupting portion 111. Therefore, regardless of the formation position of the anode electrode 101, the current interrupting unit 111 has a constant size, and the reliability of the repair process can be further improved.

  FIG. 6 is a top view of an organic EL element in which the arrangement of subpixels is changed.

  In the form shown in FIG. 6, the contact hole 110 is shared by a plurality of subpixels. When this mode is applied, the pixel density can be increased by using a common contact hole.

  FIG. 7 is a cross-sectional view around the contact hole.

  In the form shown in FIG. 7, the current interrupting portion 111 is formed on the slope portion of the contact hole 110. By using a sputtering method when forming the anode electrode 101, the film thickness at the inclined surface portion can be made thinner than the flat surface portion. In this embodiment, the thickness of the anode electrode in the plane portion was 0.1 microns, and the slope portion was 0.05 microns. If the current interrupting portion 111 is formed on the slope portion of the contact hole 110, the thickness can be reduced and the cutting is easy.

  As mentioned above, although embodiment of this invention was described, when using the organic electroluminescent display of this invention as a large screen display (display of diagonal 10 inches or more), it can apply preferably. In the case of a large screen display, a structure in which one pixel is divided into a plurality of parts as in the present invention can be manufactured with a higher yield. Further, the non-lighting organic EL element becomes more conspicuous as the area of one pixel increases, but the present invention has a great effect of solving this problem. Such a display can be preferably used for a television receiver or a computer monitor.

It is a top view which shows a part of organic EL display which arranged the organic EL element of this invention. It is element sectional drawing for demonstrating the manufacturing method of the organic electroluminescent display of this invention. It is a flowchart for demonstrating the restoration method of the non-lighting organic EL element of this invention. It is element sectional drawing for demonstrating the manufacturing method of the other organic electroluminescent display of this invention. It is a top view of a contact hole periphery. It is a top view of the organic EL element in which the arrangement of subpixels is changed. It is element sectional drawing of a contact hole periphery part. It is explanatory drawing of a prior art example.

Explanation of symbols

101, 102, 103, 104 Lower electrode 105 Switching element 106 Connection line 107 Vertical wiring 108 Horizontal wiring 109 Upper electrode 110 Contact hole 111 Current blocking part 112 Substrate 113 Planarization film 114 Insulation part 115 Organic vapor deposition layer 501 Connection part

Claims (5)

In an active matrix type organic EL display in which switching elements and organic EL elements are arranged,
An organic EL display, wherein each organic EL element has a plurality of subelements, and a current blocking portion is provided in a non-light-emitting region between the switching element that drives the organic EL element and each subelement.   The organic EL display according to claim 1, wherein the lower electrode is divided.   3. The organic material according to claim 1, wherein the divided lower electrode is divided by an insulating portion having a flat surface substantially flush with a light extraction side surface of the lower electrode in the light emitting region. EL display.   2. The organic EL display according to claim 1, wherein the current interrupting portion is formed in a contact hole region formed in a planarizing film that covers the switching element. A method of repairing an active matrix type organic EL display in which switching elements and organic EL elements are arranged,
In the organic EL display, each organic EL element has a plurality of sub-elements, and has a current blocking unit between the switching element that drives the organic EL element and each sub-element,
A step of detecting a non-lighted organic EL element when the organic EL display emits light;
Detecting a short-circuited sub-element among the non-lighting organic EL elements;
Cutting the current interrupting unit connected to the shorted subelement;
A method for repairing an organic EL display, comprising:

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