JP2005285523A - Organic electroluminescent panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL panel capable of carrying out original displays without accelerating degradation of an organic layer to improve its product properties. <P>SOLUTION: The organic EL panel 1 has an organic EL element 3 made by forming an organic layer having at least a luminous layer between a pair of electrodes (first and second electrodes) 3a, 3b arranged on a substrate 2. One of the electrodes 3a is provided with a brightness adjustment part for changing its resistance values continuously or step by step in accordance with one luminous part (a display part) S1 to change luminous brightness of the luminous part S1 continuously or step by step. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic EL panel in which an organic EL (electroluminescence) element is disposed on a translucent substrate.

  Conventionally, on a translucent substrate, made of a translucent conductive material such as ITO (Indium Tin Oxide), a first electrode serving as an anode, an organic layer having at least a light emitting layer, aluminum (Al) or magnesium An organic EL panel made of a conductive material having a lower resistivity than the first electrode, such as silver (Mg: Ag), and having an organic EL element sequentially formed with a second electrode serving as a cathode is known. (For example, refer to Patent Document 1).

In such an organic EL panel, a direct current power source is connected between the first electrode and the second electrode, and a current is supplied between the two electrodes, whereby the organic layer emits light, and the emitted light is emitted from the substrate. The laminated portion of the first electrode, the organic layer, and the second electrode serves as a light emitting portion.
Japanese Patent Laid-Open No. 5-234681

  When the organic EL panel is applied to a display device such as an instrument for a vehicle, it has been desired to improve the merchantability of the organic EL panel by devising a display method using the light emitting unit.

  The applicant of the present application pays attention to the above-mentioned problem, and in Patent Document 2, the organic layer is irradiated with ultraviolet rays to set a modification level in the organic layer, thereby forming a plurality of light emitting regions having different emission luminances. In addition, a method for obtaining a gradation effect in the light emitting portion has been proposed.

  However, in such a method, there is a concern that the organic material constituting the organic layer is accelerated by irradiating the organic layer with ultraviolet rays, the luminance of the organic EL element is rapidly reduced, and the light emission lifetime is shortened. Therefore, other structures for obtaining a gradation effect are desired.

  This invention pays attention to such a problem, and it aims at providing the organic EL panel which can perform novel display without accelerating deterioration of an organic layer, and can improve the commercial property of an organic EL panel. To do.

  In order to solve the above-mentioned problems, the present invention provides an organic EL panel in which an organic EL element formed by forming an organic layer having at least a light emitting layer between a pair of electrodes is formed on a substrate, The electrode is characterized by comprising a resistance adjusting section for changing the resistance value of the electrode continuously or stepwise according to the formation location.

  In addition, the resistance adjustment unit has a low resistance value of the electrode in the vicinity of the current injection unit to which current is injected, and a high resistance value of the electrode continuously or stepwise according to the distance from the current injection unit. It is formed so that it may become.

  Further, the resistance adjusting portion is formed so as to have different widths continuously or stepwise.

  Further, the resistance adjusting portion is formed to have different thicknesses continuously or stepwise.

  The present invention relates to an organic EL panel in which an organic EL element is disposed on a light-transmitting substrate, and performs novel display without accelerating the deterioration of the organic layer, thereby improving the merchantability of the organic EL panel. Make it possible.

  Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, the organic EL panel 1 includes an organic EL element 3 disposed on a substrate 2 made of a light-transmitting glass material. A sealing member 4 is disposed on the substrate 2 so as to cover the organic EL element 3 in an airtight manner.

  The organic EL element 3 is formed by sequentially laminating a first electrode 3a, an insulating layer 3b, an organic layer 3c, and a second electrode 3d. The first electrode 3a, the organic layer 3c, and the second electrode The display portion (light emitting portion) S1 is configured by the laminated portion 3c.

  The first electrode 3a is connected to an external power source (not shown) and serves as an anode for injecting holes into the organic layer 3c. A conductive material such as ITO is deposited on the substrate 2 by means such as vapor deposition or sputtering. Is formed into a layer having a film thickness of 50 to 200 nm and patterned by a photolithography method or the like. The first electrode 3a includes an anode part 3a1 corresponding to the display part S1 and a resistance adjusting part 3a2 extending in the A direction from the anode part 3a1. An anode lead 3a3 is drawn out from the first electrode 3a, and an anode terminal 3a4 is provided at the end of the anode lead 3a3. The first electrode 3a is connected to the external power source via the anode lead 3a1, the anode terminal 3a4, and a predetermined circuit board (not shown), and is shown in FIG. Current is injected in the direction of arrow B. In addition, the resistance adjusting unit 3a2 has the longest length in the A direction (hereinafter referred to as a width) that is substantially perpendicular to the current injection direction in the vicinity of the current injection unit 3a5, and the distance from the current injection unit 3a5 increases. Accordingly, the width is gradually (continuously) shortened. Accordingly, the first electrode 3a is formed so that the resistance value is low in the vicinity of the current injection portion 3a5 and the resistance value is continuously increased according to the distance from the current injection portion 3a5. In addition, since resistance adjustment part 3a2 overlaps with insulating layer 3b, it does not contribute to light emission.

  The insulating layer 3b is made of an insulating material such as polyimide or phenol, and is formed in a predetermined shape on a non-light emitting portion on the support substrate 2 by means such as photolithography. The insulating layer 3b is formed so as to slightly overlap the peripheral edge of the anode portion 3a1 of the first electrode 3a in order to display the outline of the display portion S clearly, and the insulation between the first electrode 3a and the second electrode 3d is formed. It is formed to ensure.

  The organic layer 3c is formed with a predetermined size on the first electrode 3a and the insulating layer 3b so as to correspond to a portion where the anode portion 3a1 of the first electrode 3a is exposed. In the present embodiment, A hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are sequentially laminated by means such as vapor deposition. The organic layer 3c only needs to have at least a light emitting layer.

  The second electrode 3d is connected to the external power source and serves as a cathode for injecting electrons into the organic layer 3c. A conductive material such as aluminum (Al) or magnesium silver (Mg: Ag) is used as a vapor deposition method or the like. Is formed in a layered form with a film thickness of 50 to 200 nm on the organic layer 3c. The second electrode 3d is connected to a cathode lead 3d1 formed of the same material as the first electrode 3a, and a cathode terminal 3d2 is formed at the terminal portion of the cathode lead 3d1.

  The sealing member 4 is formed by forming a concave portion 4a in a flat plate member made of, for example, a glass material by an appropriate method such as sandblasting, cutting, and etching. The sealing member 4 is hermetically disposed on the substrate 2 via a bonding agent 4c made of, for example, an ultraviolet curable epoxy resin. And the substrate 2 seal the organic EL element 1.

  The organic EL panel 1 having such a configuration is formed such that the resistance value of the first electrode 3a continuously changes in accordance with the formation position of the first electrode 3a corresponding to one display portion S1. In order to change the resistance value of one electrode 3a, a resistance adjusting portion 3a2 having continuously different widths is provided. Therefore, the organic EL element 3 provided in the organic EL panel 1 has a high light emission luminance because a current easily flows at a portion where the resistance value of the first electrode 3a is low, and a portion where the resistance value of the first electrode 3a is high. In FIG. 5, since the current does not easily flow, the light emission luminance is low, and it is possible to obtain a gradation effect in which the light emission luminance varies stepwise in one display unit S1. Moreover, since the light emission luminance in the display unit S1 is changed by changing the resistance value of the first electrode 3a, the deterioration of the organic layer 3c is accelerated as compared with the conventional method of irradiating the organic layer with ultraviolet rays. It is possible to obtain a gradation effect. In the first embodiment, the resistance adjustment portion 3a2 has continuously different widths, but has a plurality of regions having different widths, that is, steps that are formed so that the widths are gradually different. The structure which provides a shape-like resistance adjustment part may be sufficient. In such a configuration, the resistance value of the first electrode 3a changes stepwise, and the organic EL panel 1 has a gradation effect in which the luminance varies stepwise in one display portion S1 formed by the organic EL element 3. Can be obtained. In the first embodiment, the first electrode 3a is a portion where the anode portion 3a1 corresponds to the display portion S1, and the resistance adjusting portion 3a2 is covered with the insulating layer 3b. In this case, a portion corresponding to one display portion of the first electrode may include a resistance adjustment portion, and the width of the display portion may be different continuously or stepwise.

  The organic EL panel 1 is formed such that the resistance adjusting portion 3a2 has the longest width in the vicinity of the current injection portion 3a5 and continuously decreases as the distance from the current injection portion 3a5 increases. In the vicinity of the current injection portion 3a5, the resistance value of the first electrode 3a is low, and the resistance value is continuously increased according to the distance from the current injection portion 3a5. Accordingly, current flows easily in the vicinity of the current injection portion 3a5 of the first electrode 3a, and current does not easily flow as the distance from the current injection portion 3a5 increases, so that excessive current injection in the current injection portion 3a5 occurs. A gradation effect can be clearly obtained without being obstructed.

  Next, the organic EL panel 10 which is 2nd embodiment of this invention is demonstrated using FIG.3 and FIG.4. In addition, the same code | symbol is attached | subjected to the part same as the above-mentioned 1st embodiment, or an equivalent part, and the detailed description is abbreviate | omitted.

  The organic EL element 3 is formed by sequentially laminating a first electrode 3e, an insulating layer 3b, an organic layer 3c, and a second electrode 3d. The first electrode 3e, the organic layer 3c, and the second electrode The display portion (light emitting portion) S2 is configured by the laminated portion 3c.

  The first electrode 3e is connected to an external power source (not shown) and serves as an anode for injecting holes into the organic layer 3c. A conductive material such as ITO is deposited on the substrate 2 by means such as vapor deposition or sputtering. It is formed in a layer form by photolithography and patterned by a photolithography method or the like. The first electrode 3e includes an anode part 3e1 corresponding to the display part S2 and a resistance adjusting part 3e2 formed integrally on the anode part 3e1. An anode lead 3e3 is drawn from the first electrode 3e, and an anode terminal 3e4 is provided at the end of the anode lead 3e3. The first electrode 3e is connected to the external power source via the anode lead 3e3, the anode terminal 3e4, and a predetermined circuit board (not shown), and is connected to the anode lead portion 3e3 from the current injection portion 3e5 to FIG. Current is injected in the direction of arrow B shown. The resistance adjusting portion 3e2 is thickest in the vicinity of the current injection portion 3e5, and is formed so as to gradually become thinner as the distance from the current injection portion 3e5 increases. Therefore, the first electrode 3e is formed so that the resistance value is low in the vicinity of the current injection portion 3e5, and the resistance value is continuously increased according to the distance from the current injection portion 3e5.

  The organic EL panel 10 having such a configuration is formed such that the film thicknesses of the first electrodes 3e are continuously different depending on where the first electrode 3e is formed by laminating the resistance adjusting portions 3e2 having different thicknesses on the anode 3e1. That is, the resistance value of the first electrode 3e continuously changes in accordance with the location corresponding to one display portion S2. Accordingly, the organic EL element 3 provided in the organic EL panel 10 has a high light emission luminance because a current easily flows at a location where the resistance value of the first electrode 3e is low, and a location where the resistance value of the first electrode 3e is high. In this case, since the current does not easily flow, the light emission luminance is low, and it is possible to obtain a gradation effect in which the light emission luminance is continuously different in one display unit S2. In addition, since the light emission luminance in the display unit S2 is changed by changing the resistance value of the first electrode 3e, the deterioration of the organic layer 3c is accelerated as compared with the conventional method of irradiating the organic layer with ultraviolet rays. It is possible to obtain a gradation effect. In the second embodiment, the resistance adjustment unit 3e2 has a structure in which the film thickness is continuously different. However, the stepwise resistance adjustment unit having a plurality of regions having different film thicknesses in the first electrode 3e. The structure which is provided and formed so that the film thickness of the 1st electrode 3e may differ in steps may be sufficient. In such a configuration, the resistance value of the first electrode 3e changes stepwise at a position corresponding to one display unit S2, and the organic EL panel 10 includes one display unit formed by the organic EL element 3. In S2, it is possible to obtain gradation effects having different luminances in stages.

  Further, the organic EL panel 10 is formed such that the first electrode 3e is thickest in the vicinity of the current injection portion and continuously thins as the distance from the current injection portion 3e3 increases. In the vicinity of 3e3, the resistance value is low, and the resistance value is continuously increased according to the distance from the current injection portion 3e3. Accordingly, current flows easily in the vicinity of the current injection portion 3e3 of the first electrode 3e, and current hardly flows as the distance from the current injection portion 3e3 increases. Therefore, excessive current injection in the current injection portion 3e3 occurs. A gradation effect can be clearly obtained without being obstructed.

  The present invention can be applied to any organic EL panel including either a segment type organic EL element or a dot matrix type organic EL element.

  In the first and second embodiments, the organic EL panels 1 and 10 are configured to include one display unit S1 and S2. However, the present invention is an organic EL including a plurality of light emitting units. Applicable even to a panel, and by providing a resistance adjusting portion on one electrode, a gradation effect in which the light emission luminance is varied for each light emitting portion or the light emission luminance is gradually changed in each light emitting portion. Can be obtained.

  In the first and second embodiments, the resistance adjusters 3a2 and 3e2 are formed on the first electrodes 3a and 3e, respectively, which serve as anodes. May be formed on the organic layer and formed on the second electrode serving as the cathode.

The top view explaining the organic electroluminescent panel which is 1st embodiment of this invention. Sectional drawing explaining an organic electroluminescent panel same as the above. The top view explaining the organic electroluminescent panel which is 2nd embodiment of this invention. Sectional drawing explaining an organic electroluminescent panel same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,10 Organic EL panel 2 Substrate 3 Organic EL element 3a, 3e First electrode 3b Insulating layer 3c Organic layer 3d Second electrode 4 Sealing member

Claims (4)

An organic EL panel in which an organic EL element formed by forming an organic layer having at least a light emitting layer between a pair of electrodes is formed on a substrate,
At least one of the electrodes is provided with a resistance adjusting section for continuously or stepwise changing the resistance value of the electrode according to the formation location. The resistance adjusting unit has a low resistance value of the electrode in the vicinity of the current injection unit to which current is injected, and the resistance value of the electrode increases continuously or stepwise according to the distance from the current injection unit. The organic EL panel according to claim 1, wherein the organic EL panel is formed. The organic EL panel according to claim 1, wherein the resistance adjusting portion is formed so as to have different widths continuously or stepwise. 2. The organic EL panel according to claim 1, wherein the resistance adjusting portion is formed so as to have different thicknesses continuously or stepwise.

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