JP4989396B2 - Planar light emitting module - Google Patents

Description

  The present invention relates to a planar light emitting module.

  In recent years, when a planar light emitting module using a light emitting element such as an EL element or an LED element is used for lighting purposes, it is desired to produce gradation in the luminance distribution in the surface of the planar light emitting module for space production. There is a request.

  In contrast, a dispersion in which a reflective insulating layer is conventionally formed on a back electrode made of a metal such as aluminum, a light emitting layer is formed on the reflective insulating layer, and a transparent electrode is formed on the light emitting layer. In the type EL element, before forming the reflective insulating layer or the like on the back electrode, by etching a part of the back electrode or coating a part of the back electrode with an inter-electrode electric field strength difference layer, Dispersion type EL which can give a difference in electric field strength between the back electrode and the transparent electrode between a part of the back electrode and the other part and can have an in-plane luminance distribution An element has been proposed (see Patent Document 1).

  However, in the planar light emitting module disclosed in Patent Document 1, when a gradation is generated in the in-plane luminance distribution, the back electrode is etched stepwise, or the stepped electrode is formed on the back electrode. Fine processing such as coating the electric field strength difference layer is necessary, and there is a problem that the degree of difficulty of processing is high.

In addition, there has been proposed a planar light emitting module that has a plurality of strip-shaped light emitting elements, and the plurality of light emitting elements are arranged in a line on the same surface. In this planar light emitting module, the control circuit controls the current supplied to each light emitting element so as to increase or decrease stepwise in the direction in which the light emitting elements are arranged in parallel. Can be generated.
Japanese Patent Laid-Open No. 6-203156

  However, in the planar light emitting module in which a plurality of light emitting elements are arranged in parallel as described above, it is necessary to individually control the current supplied to each light emitting element, and thus the control circuit becomes complicated and expensive. was there.

  This invention is made | formed in view of the said reason, It is providing the planar light emitting module which can produce a gradation in the luminance distribution in a plane using an inexpensive control circuit.

The invention according to claim 1 is a planar light emitting module having a plurality of light emitting elements and a power supply electrode for supplying a current to each light emitting element, wherein the plurality of light emitting elements are arranged in parallel in the same plane. The light emitting elements are arranged side by side, and the area of each light emitting element is changed stepwise in the parallel arrangement direction . A plurality of light emitting elements are connected in series, and current is passed between both ends of the series circuit of the plurality of light emitting elements. It is characterized by being connected to a control circuit .

  According to the present invention, a plurality of light emitting elements having different areas are arranged in the same parallel arrangement direction in the same plane, and the area of each light emitting element is changed stepwise in the parallel arrangement direction. A gradation can be generated in the luminance distribution. Further, the gradation generated in the luminance distribution can be easily changed simply by changing the area ratio of each light emitting element.

Further, according to this invention, by using a simple and inexpensive control circuit to energize the constant current across the series circuit of multiple light-emitting element, it is possible to produce a gradient to the brightness distribution.

According to a second aspect of the present invention, in the first aspect of the present invention, a concavo-convex portion is formed at an opposing edge of a light-emitting element adjacent to each other among the plurality of light-emitting elements. It is characterized by being arranged so as to penetrate each other.

  According to the present invention, the uneven portions are formed at the opposing edges of the light emitting elements adjacent to each other among the plurality of light emitting elements, and the adjacent light emitting elements are arranged in such a manner that the uneven portions enter each other. Therefore, when the gradation is generated, the boundary between the light emitting elements adjacent to each other becomes ambiguous, and a smooth gradation can be generated by the luminance distribution.

  According to the first aspect of the present invention, a plurality of light emitting elements having different areas are arranged side by side in a prescribed parallel arrangement direction in the same plane, and the area of each light emitting element is changed stepwise in the parallel arrangement direction. Thus, gradation can be easily generated in the luminance distribution. Further, the gradation generated in the luminance distribution can be easily changed simply by changing the area ratio of each light emitting element.

(Embodiment 1)
As shown in FIG. 1, the planar light emitting module 1 of the present embodiment includes a plurality of light emitting elements 2 and two power feeding electrodes 3 and 3 that supply current to each light emitting element 2.

  The light emitting element 2 is an organic EL element, and as shown in FIG. 1 (a), for example, one surface of a rectangular plate-shaped translucent substrate 21 formed of a translucent insulating material such as glass. On top, an anode 23a formed of a light-transmitting conductive material such as indium tin oxide (ITO), an organic thin film layer 22 including at least a light emitting layer (not shown), and aluminum (Al), for example. A sealing layer 4 is formed which has a laminated structure with the cathode 24 a formed of such a metal and covers the upper and side surfaces of the cathode 24 a and the side surface of the organic thin film layer 22. Here, the planar light emitting module 1 uses the other surface of the translucent substrate 21 as a light emission surface (light extraction surface) 1a.

  The organic thin film layer 22 is configured so that the light emitting layer emits light when a direct current is passed between the anode 23a and the cathode 24a, and the organic thin film layer 22 obtains light of a desired emission color. A light emitting layer formed of an organic molecular material, a hole transport layer (not shown) interposed between the light emitting layer and the anode 23a, and an electron transport layer (not shown) interposed between the light emitting layer and the cathode 24a. Not shown). Here, the layer structure of the organic thin film layer 22 is not particularly limited. For example, when the desired light emission color of the organic thin film layer 22 is white, three kinds of dopant dyes of red, green, and blue are included in the light emission layer. It is possible to adopt a laminated structure of a hole transport layer, a light emitting layer, and an electron transport layer so as to be doped, a blue hole transport light emitting layer, a green electron transport light emitting layer, and a red electron transport property. A laminated structure with a light emitting layer may be adopted, or a laminated structure of a hole transporting layer, a blue electron transporting light emitting layer, a green electron transporting light emitting layer, and a red electron transporting light emitting layer may be adopted. Further, the organic thin film layer 22 may be constituted only by the light emitting layer without providing the hole transport layer and the electron transport layer.

  Note that the light-emitting element 2 made of the above-described organic EL element can be driven with lower power and lower current than, for example, an inorganic EL element, and has a large light emission luminance with respect to supplied power and high light emission efficiency. There is.

  In the light emitting element 2, one end of the anode 23 a that is not covered with the organic thin film layer 22 constitutes the anode side terminal 23 b. On the other hand, in the cathode 24a, a portion extending from the upper surface of the organic thin film layer 22 to the one surface of the translucent substrate 21 toward the side of the other end of the anode 23a constitutes a cathode side terminal 24b. A part of the organic thin film layer 22 is interposed between the anode 23a and the cathode 24a. Further, the sealing layer 4 is formed of, for example, a silicone resin.

  The power supply electrode 3 is formed by, for example, chromium plating, and is exposed without being covered with the sealing layer 4. Further, one power supply electrode 3 is connected to the anode side terminal 23b via a wiring portion 31 formed by, for example, chromium plating, and the other power supply electrode 3 is connected to the cathode side terminal via the wiring portion 31. 24b.

  As shown in FIG. 1B, the planar light emitting module 1 of the present embodiment has a plurality of strip-shaped light emitting elements 2 having different sizes in plan view (that is, a plurality of different width dimensions). The plurality of light emitting elements 2 are arranged in a line in the prescribed parallel direction in the same plane. Hereinafter, description will be made assuming that the parallel arrangement direction of the light emitting elements 2 in FIG.

  The area of the plurality of light emitting elements 2 is changed from the leftmost light emitting element 2 toward the rightmost light emitting element 2 in FIG. Specifically, the area of the light emitting element 2 at the left end is the smallest, and the area of the light emitting element 2 at the right end is increased in a stepwise manner. Here, the luminance of each light emitting element 2 is proportional to the density of the energized current. Therefore, when a constant current is applied to each light emitting element 2 by a control circuit (not shown), the current density increases as the area of the light emitting element 2 decreases. A gradation in which the luminance gradually decreases from the left end to the right end can be generated.

  Moreover, in the planar light emitting module 1 of this embodiment, the some light emitting element 2 comprises the series circuit. Therefore, the planar light emitting module 1 can emit light by connecting a simple and inexpensive control circuit (not shown) that supplies a constant current between both ends of a series circuit composed of a plurality of light emitting elements 2.

  Moreover, in the structure of FIG. 2 illustrated as another structural example of the planar light emitting module 1 of the present embodiment, a triangular wave-shaped uneven portion is formed on the opposing edge of the adjacent light emitting elements 2, 2. Adjacent light-emitting elements 2 and 2 are arranged in such a way that triangular wave-shaped uneven portions enter each other. Thus, by blurring the boundary between the adjacent light emitting elements 2 and 2 when the gradation is generated, it is possible to generate a smooth gradation by the luminance distribution.

  Furthermore, in the planar light emitting module 1 of the present embodiment, a boundary between adjacent light emitting elements 2 and 2 when gradation is generated by attaching a light diffusion sheet (not shown) to the light emitting surface 1a. Can be further obscured to produce a smoother gradation in the luminance distribution.

  As an application example of the planar light emitting module 1 of the present embodiment, for example, a planar light emitting lighting fixture (not shown) including the planar light emitting module 1 and a lighting device for the planar light emitting lighting fixture are controlled. And a planar light emitting system (not shown) provided with a control device (not shown).

  The above-described planar light-emitting luminaire controls the light distribution from the planar light-emitting module 1, the DC power supply circuit (not illustrated), and the planar light-emitting module 1 in one housing (not shown). An optical element (not shown) is arranged.

  The DC power supply circuit described above includes a diode bridge (not shown) for full-wave rectification of an AC output of a commercial power supply (not shown) and a step-down chopper circuit (not shown) for stepping down the output of the diode bridge. Yes. Here, in the step-down chopper circuit, a switching element (not shown) made of, for example, an FET and a diode (not shown) are connected between the output ends of the diode bridge, and an inductor (not shown) is smoothed between both ends of the diode. A series circuit with a capacitor (not shown) is connected, and a chopper control circuit (not shown) for controlling the voltage across the smoothing capacitor by turning on and off the switching element is provided.

(Embodiment 2)
As in the first embodiment, the planar light emitting module 1 of the present embodiment has a plurality of different sizes arranged side by side in a prescribed parallel direction (here, the left-right direction in FIG. 3) as shown in FIG. The light-emitting element 2 is provided, and the area is changed from the central light-emitting element 2 toward the light-emitting elements 2 and 2 at the left and right ends. Specifically, the area of the light emitting element 2 at the center is the smallest, and the area of the light emitting elements 2 at both the left and right ends is increased stepwise. Here, when a constant current is supplied to each light emitting element 2 by the control circuit (not shown) described in the first embodiment, the current density increases as the area of the light emitting element 2 decreases. It is possible to generate a gradation in which the luminance gradually decreases from the center to the left and right ends in the luminance distribution of the module 1.

(Embodiment 3)
The planar light emitting module 1 of the present embodiment has a plurality of light emitting elements 2 having different sizes as in the case of the first embodiment. As shown in FIG. The light emitting elements 2 are arranged in a dimensional manner, and the area of each light emitting element 2 is changed stepwise in a specified parallel direction (here, the left and right direction in FIG. 4). Specifically, the area of the leftmost light emitting element 2 is the smallest, and the area of the light emitting element 2 is increased stepwise by gradually increasing the vertical width in FIG. 4 toward the right side. The area of the light emitting element 2 is increased stepwise by increasing the width in the left and right directions stepwise while keeping the width in the direction constant, so that the area of the rightmost light emitting element 2 is maximized. Here, when a constant current is supplied to each light emitting element 2 by the control circuit (not shown) described in the first embodiment, the current density increases as the area of the light emitting element 2 decreases. It is possible to generate a gradation in which the luminance gradually decreases from the left end to the right end in the luminance distribution of the module 1. Further, since the area is changed stepwise by changing the vertical width of the light emitting element 2, the area ratio of each light emitting element 2 can be further increased as compared with the first embodiment, and the area of the planar light emitting module 1 can be increased. It is possible to generate a gradation in which the density is further enhanced in the luminance distribution.

  In each of the above-described embodiments, the case where an organic EL element is employed as the light emitting element 2 has been described. However, even when another light emitting element such as an inorganic EL element or an LED element is employed as the light emitting element 2, the same effect can be obtained. can get.

The planar light emitting module of Embodiment 1 is shown, (a) is the perspective view which a part of light emitting element fractured | ruptured, (b) is a principal part schematic plan view. It is a principal part schematic plan view of the other structural example same as the above. It is a principal part schematic plan view of the planar light emitting module of Embodiment 2. FIG. It is a principal part schematic plan view of the planar light emitting module of Embodiment 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar light emitting module 1a Light emission surface 2 Light emitting element 3 Feeding electrode

Claims (2)

A planar light-emitting module having a plurality of light-emitting elements and a power feeding electrode for supplying a current to each light-emitting element, wherein the plurality of light-emitting elements are juxtaposed in a prescribed parallel direction in the same plane, The area of the light emitting elements is changed stepwise in the parallel direction, and a plurality of light emitting elements are connected in series, and are connected to a control circuit that is energized between both ends of the series circuit of the plurality of light emitting elements. The planar light emitting module characterized by the above-mentioned. The uneven portions in opposing edges of the light-emitting element adjacent to each other among the plurality of light-emitting element is formed, the adjacent light-emitting elements are characterized by irregularities of one another, which are arranged in the form of interdigitated The planar light emitting module according to claim 1 .

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