JP2011118266A - Organic el panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL panel in which variation of light emission luminance of each display part is suppressed, and display quality can be improved. <P>SOLUTION: The organic EL panel includes: a translucent supporting substrate; a plurality of light emitting parts S1-S8 on which a first electrode, an organic light emitting layer, and a second electrode are laminated; and a plurality of wiring parts L1 to L8 formed on the supporting substrate and supplying a current to each of the light emitting parts S1-S8. A shunt part R1 connected to at least one of the wiring parts L1-L8 and shunting a current supplied to the light emitting parts S1-S8 is formed on the supporting substrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic EL (electroluminescence) panel.

  2. Description of the Related Art Conventionally, an organic EL panel including an organic EL element that is a self-luminous element formed of an organic material includes, for example, a first electrode made of indium tin oxide (ITO) or the like serving as an anode, and an organic layer including an organic light emitting layer In addition, a non-translucent second electrode made of aluminum (Al) or the like serving as a cathode and a layer sequentially laminated on a translucent support substrate are known (for example, see Patent Document 1). Such an organic EL element emits light by injecting holes from the first electrode and injecting electrons from the second electrode, and the holes and electrons recombine in the organic light emitting layer. Since the organic EL panel is excellent in visibility and responsiveness in a low temperature environment, it is desired that the organic EL panel be applied to a display device such as a vehicle instrument that requires instantaneous interpretation of display.

  In addition, the organic EL panel includes a dot matrix type in which light emitting portions made of organic EL elements are arranged in a matrix and a segment type in which a plurality of light emitting portions are arranged to obtain an arbitrary light emission shape such as characters. The segment type organic EL panel has an advantage that a desired light emission shape can be easily obtained. For example, it is known that seven light emitting portions are arranged in an eight-letter shape to display numbers from “0” to “9”. It has been.

JP 59-194393 A JP 09-305146 A

  By the way, in the organic EL panel, in order to make each light emitting part emit light with the same luminance, it is necessary to make the current density of each light emitting part uniform. However, in the segment type organic EL panel, the area of each light emitting part is often different, and when light is emitted with the same current value, the light emission luminance varies among the display parts. On the other hand, a method of adjusting the output current of the driver IC in accordance with each light emitting unit and matching the light emission luminance of each light emitting unit having a different area has been conventionally considered (see, for example, Patent Document 2).

  However, since the resolution of the output current of the driver IC is limited, there is a difference between the current value that can be actually adjusted and the target value for achieving the same luminance, and the current density of each light emitting unit cannot be made uniform. As a result, there has been a problem that unevenness occurs in light emission luminance.

  The present invention has been made in view of this problem, and provides an organic EL panel that can suppress unevenness in light emission luminance of each display unit and improve display quality particularly in a segment type organic EL panel. It is for the purpose.

  In order to solve the above-described problems, the present invention provides a light-transmitting support substrate, and a plurality of light-emitting elements formed by laminating a light-transmitting first electrode, an organic light-emitting layer, and a second electrode on the support substrate. And a plurality of wiring parts that are formed on the support substrate and individually supply current to the light emitting parts, and are connected to at least one of the wiring parts, and the light emitting parts A shunt part for shunting a current supplied to the substrate is formed on the support substrate.

  In addition, the diversion part is composed of a discharge element.

  The discharge element may have the same stacked structure as the light emitting unit.

  Further, a light-shielding layer that shields light emitted from the discharge element is provided so as to face the discharge element.

  Further, the light shielding layer is formed wider than the discharge element.

  Further, the shunt portion is formed of a discharge resistor.

  The present invention particularly relates to a segment-type organic EL panel, which can suppress unevenness in light emission luminance of each display unit and improve display quality.

The principal part front view which shows the organic electroluminescent panel which is embodiment of this invention. The principal part sectional drawing which shows the segment part of an organic electroluminescent panel same as the above. The principal part sectional drawing which shows the discharge element of an organic electroluminescent panel same as the above. The principal part front view which shows other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The organic EL panel has an area smaller than the seven segment portions (light emitting portions) S1 to S7, which are arranged in the shape of 8 and can display the numbers “0” to “9”, and the segment portions S1 to S7. And a dotted segment portion (light emitting portion) S8 indicating a period or a decimal point.

  Each segment part S1-S8 consists of an organic EL element, and as shown in FIG. 2, the 1st electrode 2 is pattern-formed on the support substrate 1 according to each segment part S1-S8, and also the insulating film 3 The organic layer 4 and the second electrode 5 are sequentially stacked.

  The support substrate 1 is a translucent substrate made of, for example, a glass material.

  The first electrode 2 is made of a translucent conductive material such as ITO, for example, and is formed by patterning this conductive material on the support substrate 1 in a shape corresponding to the segment portions S1 to S8 by means such as sputtering.

  The insulating film 3 is made of, for example, a polyimide-based insulating material, and is formed on the support substrate 1 to prevent a short circuit between the first electrode 2 and the second electrode 5 by means such as sputtering. The insulating film 3 is formed so as to expose the first electrode 2 constituting each of the segment portions S1 to S8. The insulating film 3 is formed so as to slightly overlap the peripheral edge portion of the first electrode 2 in order to make the outlines of the segment portions S1 to S8 clear.

  The organic layer 4 only needs to include at least an organic light emitting layer. For example, the hole injection layer, the hole transport layer, the organic light emitting layer, the electron transport layer, and the electron injection layer are formed by a method such as vapor deposition. 2 are sequentially stacked.

  The second electrode 5 is made of a conductive material such as aluminum (Al), for example, and is formed on the organic layer 4 by means of a vapor deposition method or the like. The second electrode 5 is formed so as to cover the entire surface corresponding to the segment portions S1 to S8, and is connected to a constant current source via a terminal portion (not shown) formed on the support substrate 1. .

  Further, the organic EL panel has wiring portions L1 to L8 formed on the support substrate 1. The wiring portions L1 to L8 are made of, for example, a low resistance metal material such as ITO or aluminum alloy, one end is individually connected to the first electrode 2 of each segment portion S1 to S8, and the other end is electrically connected to the constant current source. Connected. That is, the organic EL panel controls the light emission of each segment part S1 to S8 by static drive, and the light emission / non-light emission of each segment part S1 to S8 is connected to the constant current source of the wiring parts L1 to L8. It is switched by turning on / off.

  Here, when the segment portions S1 to S7 have the same area and the area of the segment portion S8 is 1/8 of the area of the segment portions S1 to S7, the segment portion S8 has the same luminance as the other segment portions S1 to S7. In order to emit light, the current value applied to the segment part S8 needs to be ８ of the current value applied to the other segment parts S1 to S7 in order to make the current density uniform. However, since the resolution of the output current value of the driver IC for driving the segment portions S1 to S8 to emit light is limited, as a feature of this embodiment, the segment portion S8 having a smaller area than the other segment portions S1 to S7. The discharge element R1 was connected to the wiring portion L8 connected to the PLD as a shunt portion for shunting the current supplied to the segment portion S8. The discharge element R1 is formed on the support substrate 1 and has the same stacked structure as the segment part S8 as shown in FIG. 3, and the first electrode 2, the organic layer 4 and the second electrode 5 are sequentially stacked. Formed. By dividing and discharging the current through the discharge element R1, the current density of the segment portion S8 can be made the same as that of the other segment portions S1 to S7 without changing the output current value of the driver IC. It is possible to improve the display quality as an organic EL panel by suppressing unevenness in the emission luminance of S1 to S8. At this time, there is a problem that the discharge element R1 emits light. However, a light shielding layer 6 that blocks light emitted from the organic layer 4 is formed on the support substrate 1 so as to face the discharge element R1 on the display surface side. Thus, it is possible to prevent the light emission from the discharge element R1 from being visually recognized. In order to secure sufficient light shielding properties, it is desirable to form the light shielding layer 6 wider than the discharge element R1.

  As another embodiment of the present invention, as shown in FIG. 4, the shunt portion may be replaced with a discharge resistor R2 formed by routing a pattern of the same material as the wiring portion L8. In FIG. 4, a discharge resistor R2 is formed by forming the same material as that of the wiring portion L8 in a ladder shape. In this case, one end of the discharge resistor R2 is connected to the wiring portion L8, and the other end is connected to the ground potential (0 V) or a potential lower than the voltage before the shunting. With this configuration, the current density of the segment portion S8 can be made the same as that of the other segment portions S1 to S7 by dividing the current through the discharge resistor R2 and discharging the same as in the above-described embodiment. It is possible to improve the display quality as the organic EL panel by suppressing the light emission luminance unevenness of the portions S1 to S8.

  The present invention mainly relates to an organic EL panel, and is particularly suitable for a segment type organic EL panel having a plurality of light emitting portions having different areas.

DESCRIPTION OF SYMBOLS 1 Support substrate 2 1st electrode 3 Insulating film 4 Organic layer 5 2nd electrode 6 Light-shielding layer S1-S8 Segment part (light emission part)
L1 to L8 Wiring part R1 Discharge element (diversion part)
R2 Discharge resistance (divider)

Claims (6)

A translucent support substrate, a plurality of light emitting portions formed by laminating a translucent first electrode, an organic light emitting layer, and a second electrode on the support substrate, and each of the light emitting portions formed on the support substrate An organic EL panel comprising: a plurality of wiring units that individually supply current to the light emitting unit;
An organic EL panel, comprising: a shunt portion that is connected to at least one of the wiring portions and shunts a current supplied to the light emitting portion on the support substrate. The organic EL panel according to claim 1, wherein the shunt portion includes a discharge element. The organic EL panel according to claim 2, wherein the discharge element has the same laminated structure as the light emitting unit. The organic EL panel according to claim 2, wherein a light shielding layer that shields light emitted from the discharge element is provided so as to face the discharge element. 5. The organic EL panel according to claim 4, wherein the light shielding layer is formed wider than the discharge element. The organic EL panel according to claim 1, wherein the shunt portion is made of a discharge resistor.

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