JP2011034725A - Planar light-emitting unit and planar light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planar light-emitting unit and a planar light-emitting device capable of alleviating luminance unevenness and restraining degradation of light-extraction efficiency. <P>SOLUTION: The planar light-emitting unit 1 is provided with a translucent substrate 2, two nearly triangular first translucent electrode layers 3 formed on the substrate 2, with a whole body taking on nearly a rectangular shape divided by a line segment on a diagonal line, an auxiliary electrode 7 smaller in a resistive value than the first electrode layer 3 fitted along each side of the triangular shape, an organic EL light-emitting layer 4 formed on the first electrode layers 3 and likewise taking on a rectangular shape as the first electrode layers 3, and a second electrode layer 5 formed on the organic EL light-emitting layer 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a planar light emitting unit and a planar light emitting device using an organic EL element.

  Conventionally, in this type of light emitting device using an organic EL element, an organic EL light emitting layer is formed by vapor deposition on a substrate on which a transparent electrode layer functioning as an anode is formed, and a metal thin film functioning as a cathode is formed thereon. Formed and configured. In order to use this light-emitting device for illumination, an attempt has been made to increase the area of the light-emitting surface.

  However, since the anode formed of the transparent electrode layer has a large resistance value, when power is supplied from a power supply terminal provided at one end of the anode when the area is increased, a voltage is generated at a portion away from the power supply terminal. The voltage drop is large, the voltage applied to the light emitting surface, that is, the organic EL light emitting layer varies depending on the position, and uneven brightness occurs, resulting in a problem that uniform light emission cannot be obtained.

  For this reason, in order to solve these problems, an illumination EL panel in which a low-resistance metal electrode layer in which a window is partially formed on a transparent electrode layer is formed has been proposed (see Patent Document 1).

Japanese Patent Laid-Open No. 11-971813

  However, although what was shown by patent document 1 has a window partially formed, it forms a metal electrode layer corresponding to the substantially whole surface of a transparent electrode layer. Therefore, it seems that it is possible to reduce luminance unevenness and make the entire EL panel emit light uniformly, but this metal electrode layer blocks the light emitted from the organic EL light emitting layer. The result is a reduction in efficiency.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a planar light emitting unit and a planar light emitting device that can reduce luminance unevenness and suppress a decrease in light extraction efficiency.

  The planar light-emitting unit according to claim 1 is formed of a light-transmitting substrate; formed on the substrate, and has a substantially quadrangular shape as a whole, and is divided by a line segment on a diagonal line to form two substantially triangular shapes. A translucent first electrode layer formed; an auxiliary electrode having a smaller resistance value than the first electrode layer and provided along each side of the triangle; and formed on the first electrode layer And an organic EL light emitting layer having a substantially rectangular shape as in the case of the first electrode layer; and a second electrode layer formed on the organic EL light emitting layer.

  In the present invention and the following inventions, the technical meaning and interpretation of terms are as follows unless otherwise specified. The light-transmitting substrate can be formed of a glass plate or a transparent synthetic resin. The light-transmitting first electrode layer can be formed of a transparent material made of, for example, indium tin oxide (ITO) or indium zinc oxide (IZO). Further, for example, the first electrode layer formed on the substrate may be formed directly on the substrate or indirectly through another layer.

  The organic EL light emitting layer may be composed of a low molecular material or a polymer material, and various layer configurations and materials can be adopted as the layer configuration and materials depending on the design. The auxiliary electrode can be formed of, for example, aluminum having a resistance value smaller than that of the first electrode layer. The second electrode layer can be formed of a metal such as aluminum, magnesium, magnesium aluminum alloy, or the like. Further, the second electrode layer may be formed of a light-transmitting material.

  The planar light-emitting device according to claim 2 is a combination of the planar light-emitting units according to claim 1 so as to superpose a plurality of the planar light-emitting units. The second electrode layer of the light-emitting unit is formed using a reflective material, and the second electrode layer of another planar light-emitting unit is formed using a light-transmitting material.

  By combining a plurality of planar light emitting units so as to be polymerized in this way, it becomes possible to suppress the occurrence of color unevenness due to variations in materials forming the organic EL light emitting layer.

  According to the first aspect of the present invention, it is possible to provide a planar light emitting unit capable of reducing unevenness in luminance of light emitted from the organic EL light emitting layer and suppressing reduction in light extraction efficiency.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, a planar light emitting device capable of suppressing color unevenness and brightness unevenness due to variations in materials forming the organic EL light emitting layer is provided. Can do.

It is a disassembled perspective view which shows the planar light emission unit which concerns on the 1st Embodiment of this invention. FIG. It is sectional drawing which expands and shows the same. It is a disassembled perspective view which shows the planar light emission unit which concerns on the 2nd Embodiment of this invention. It is a disassembled perspective view which shows the planar light emission unit which concerns on the 3rd Embodiment of this invention. It is sectional drawing which decomposes | disassembles and shows the planar light-emitting device concerning embodiment of this invention. FIG.

  Hereinafter, a planar light emitting unit according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. In addition, each figure is a figure which shows a light emission unit typically, and attaches | subjects the same code | symbol to the same or an equivalent part, and abbreviate | omits the overlapping description.

  As shown in FIGS. 1 and 2, the planar light emitting unit 1 includes a light-transmitting substrate 2 having a substantially square shape, and an anode layer 3 as a first electrode layer formed on the substrate 2, The organic EL light emitting layer 4 formed on the anode layer 3, the cathode layer 5 as the second electrode layer formed on the organic EL light emitting layer 4, the anode layer 3, the organic EL light emitting layer 4, and the cathode And a sealing member 6 that hermetically seals the layer 5. These are all formed in a quadrangular shape having a substantially square shape, and the light emitting unit 1 is formed in a planar shape with a vertical and horizontal dimension of about 20 cm × 20 cm.

  The translucent substrate 2 is formed of a glass plate, a transparent polyethylene terephthalate (PET) resin, or the like. On this substrate 2, a transparent anode layer 3 having translucency made of indium tin oxide (ITO), indium zinc oxide (IZO) or the like is formed. The anode layer 3 has an approximately square shape as a whole, and is formed in two isosceles triangle shapes so as to be divided by the diagonal line segments of the square shape.

  A thin metal auxiliary electrode 7 made of aluminum or the like is formed on the lower side along the triangular sides. Therefore, two auxiliary electrodes 7 having a triangular shape are formed on the substrate 2, and the anode layer 3 is formed thereon. The auxiliary electrode 7 has a resistance value smaller than that of the anode layer 3 and is formed of a low-resistance material. Copper, iron, silver, gold, or the like can be applied in addition to aluminum. The auxiliary electrode 7 is connected to a power supply terminal 7a.

  Next, the organic EL light emitting layer 4 is formed over the entire region where the anode layer 3 is formed. As shown in FIG. 3, the organic EL light emitting layer 4 includes a hole transport layer 4a, a light emitting layer 4b, and an electron injection layer 4c, which are sequentially laminated to form a white light emitting layer. In order to make the emission color white, the light emitting layer 4b is made by laminating and mixing organic compounds that emit red, green, and blue colors, and by laminating and mixing organic compounds that emit blue and yellow, which are complementary colors. Here, a case where fluorescent materials that emit blue and yellow light are stacked will be described.

  For the hole transport layer 4a, for example, a triphenyldiamine derivative, for the light emitting layer 4b, for example, a triphenyldiamine derivative as the material for the yellow light emitting layer, a tetracene derivative for the dopant material, and an anthracene derivative for the material for the blue light emitting layer, The dopant material is a perylene derivative, and the electron injection layer 4c is laminated using, for example, lithium fluoride (LiF). Note that the layer configuration and materials of the organic EL light-emitting layer 4 are not limited to these, and various layer configurations and materials can be adopted depending on the design. In addition, an insulating member 4 e is provided on one side of the organic EL light emitting layer 4.

  Subsequently, the cathode layer 5 is formed over the entire region where the organic EL light emitting layer 4 is formed. The cathode layer 5 is made of metal, and aluminum, magnesium, magnesium aluminum alloy or the like is used. The cathode layer 5 is preferably made of a material having high light reflectivity. A power supply terminal 5 a is connected to one side of the cathode layer 5.

  Next, the anode layer 3, the organic EL light emitting layer 4, and the cathode layer 5 are hermetically sealed by a dish-shaped sealing member 6 bonded to the outer peripheral portion of the translucent substrate 2 with an adhesive 6a. Has been. The sealing member 6 is made of glass, and this sealing prevents entry of air, moisture, and the like. A getter agent 8 is attached to the inner surface of the sealing member 6. The getter agent 8 can prevent deterioration of the organic EL light emitting layer 4 due to moisture in the air.

  Since the sealing member 6 does not need to transmit light, the sealing member 6 may be configured by using a material such as metal as appropriate, and the anode layer 3 and the organic EL light emitting layer 4 are used as the sealing structure. The cathode layer 5 may be sealed by directly covering it with a silicon nitride film and a resin. Furthermore, the power supply terminal 7a connected to the auxiliary electrode 7 and the power supply terminal 5a connected to the cathode layer 5 are extended to the outside of the sealing member 6 in order to connect to the power source (FIG. 2). reference).

  1 and 2, the power supply terminal 7a connected to the auxiliary electrode 7 is connected to the positive side of the DC power supply, and the power supply terminal 5a connected to the cathode layer 5 is connected to the DC power supply. It is connected to the negative electrode side.

  The operation of the light emitting unit 1 configured as above will be described. When electric power is supplied from the DC power source to the anode layer 3 and the cathode layer 5 through the auxiliary electrodes 7 through the power supply terminals 5a and 7a, the holes emitted from the anode layer 3 and the electrons emitted from the cathode layer 5 are generated. Each is injected into the organic EL light emitting layer 4. The injected holes and electrons are combined in the organic EL light emitting layer 4. The organic molecules in the organic EL light emitting layer 4 are excited by the energy at the time of the coupling, and light emission having a color unique to the molecules is generated when returning from the excited state to the ground state again. Specifically, in this embodiment, white light emission occurs.

  And the light by this light emission is mainly radiated | emitted outside through the translucent anode layer 3 and the translucent board | substrate 2 similarly. Part of the light is reflected by the inner surface of the cathode layer 5 and is emitted to the outside through the anode layer 3 and the substrate 2.

  Here, although the anode layer 3 has a high resistance, a low-resistance auxiliary electrode 7 is formed, and power is supplied to the anode layer 3 through the auxiliary electrode 7, so that the voltage applied to the organic EL light-emitting layer 4 Is reduced depending on the position, and the power supply is made uniform. Specifically, the anode layer 3 has a triangular shape so as to be divided by line segments on a square diagonal line. The line segment on the square diagonal line is the longest line segment that crosses the square shape. Therefore, by providing the auxiliary electrode 7 according to the line segment, the action on the square anode layer 3 is increased. This is most effective in terms of uniform power supply. In addition, since the auxiliary electrode 7 is arranged along each side of the triangle including the diagonal line segment, the power supplied from the anode layer 3 to the organic EL light emitting layer 4 is made uniform, The uneven brightness of the light emitted from the organic EL light emitting layer 4 can be reduced.

  Furthermore, since the auxiliary electrode 7 is disposed along the diagonal line of the square shape, the degree of blocking the light emitted from the organic EL light emitting layer 4 can be reduced, and therefore, the luminance unevenness can be reduced. The planar light-emitting unit 1 that is effective in both reducing and suppressing the decrease in light extraction efficiency can be obtained.

  As described above, according to the present embodiment, it is possible to provide the planar light emitting unit 1 that can reduce the luminance unevenness of the light emitted from the organic EL light emitting layer 4 and can suppress the decrease in the light extraction efficiency.

  In the present embodiment, the power supply terminal 7 a connected to the auxiliary electrode 7 is provided in the left-right direction in the drawing, but may be in the front-rear direction, and the auxiliary electrode 7 is formed on the substrate 2. Although described above, it may be formed on the anode layer 3.

  Next, a planar light emitting unit according to a second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part which is the same as that of 1st Embodiment, or an equivalent, and the overlapping description is abbreviate | omitted.

  In the present embodiment, a metal auxiliary electrode 7 is formed on the side periphery along each side of the triangular anode layer 3. Therefore, the triangular anode layer 3 is first formed on the substrate 2, and then the auxiliary electrode 7 is formed on the side periphery of each side of the anode layer 3. The auxiliary electrode 7 may be formed from the side periphery to the periphery on the anode layer 3.

  As described above, according to the configuration of the present embodiment, it is possible to provide the planar light emitting unit 1 that exhibits the same effects as those of the first embodiment.

  Next, a planar light emitting unit according to a third embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the part which is the same as that of 1st Embodiment, or an equivalent, and the overlapping description is abbreviate | omitted.

  In the present embodiment, a frame-shaped metal auxiliary electrode 7 is formed on the upper side of the anode layer 3 along each side of the triangular anode layer 3. On the auxiliary electrode 7, a triangular insulating frame 7 b having the same shape as that of the anode layer 3 is formed so as to cover the auxiliary electrode 7. Therefore, the triangular anode layer 3 is first formed on the substrate 2, then the auxiliary electrode 7 is formed, the insulating layer 7 b is formed so as to cover the auxiliary electrode 7, and then the organic EL The light emitting layer 4 is formed.

  According to such a configuration, when electric power is supplied from the DC power supply via the power supply terminal 7a, the electric power is supplied to the anode layer 3 through the auxiliary electrode 7, and from the anode layer 3 to the organic EL light emitting layer 4, Then, it is supplied to the cathode layer 5. In this case, since the auxiliary electrode 7 is not in direct contact with the organic EL light emitting layer 4 and the insulating layer 7b is interposed, deterioration due to oxidation or the like of the organic EL light emitting layer 4 can be suppressed.

  As described above, according to the configuration of the present embodiment, the same effects as those of the first embodiment can be obtained, and the insulating layer 7 b is interposed between the auxiliary electrode 7 and the organic EL light emitting layer 4. Therefore, it is possible to suppress the deterioration of the organic EL light emitting layer 4.

  Next, a planar light emitting device according to an embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part which is the same as that of 1st Embodiment, or an equivalent, and the overlapping description is abbreviate | omitted. The planar light emitting device 10 of the present embodiment is based on a configuration in which a plurality of planar light emitting units 1 in the first embodiment are combined so as to be polymerized.

  In FIG. 5, the planar light emitting device 10 includes, for example, a substrate 2, an anode layer 3 including an auxiliary electrode 7 formed on the substrate 2, and an organic EL light emitting layer 4 formed on the anode layer 3. The three light emitting units 11 including the cathode layer 5 formed on the organic EL light emitting layer 4 are combined so as to be polymerized. Here, the cathode layers 51 of the two lower light emitting units 11 are formed of a light-transmitting material, and the cathode layer 5 of the light emitting unit 11 that is farthest from the light emitting surface side is the first. As in the first embodiment, it is formed of a reflective metal. As shown in FIG. 6, the three superposed light emitting units 11 are hermetically sealed by a sealing member (not shown).

  When DC power is supplied to the planar light emitting device 10 configured as described above, each organic EL light emitting layer 4 emits light. This light is emitted to the outside through the translucent anode layer 3, the substrate 2, the cathode layer 51, the organic EL light emitting layer 4, and the like. A part of the light is reflected by the inner surface of the uppermost cathode layer 5 and is emitted to the outside through the anode layer 3, the substrate 2, the cathode layer 51 and the like. The number of light emitting units 11 to be polymerized is not particularly limited.

  As described above, according to the present embodiment, when light is radiated to the outside, a plurality of organic EL light emitting layers 4 are interposed. Therefore, color unevenness and luminance unevenness due to variations in materials forming the organic EL light emitting layer 4 are eliminated. It becomes possible to suppress.

  The present invention is not limited to the configuration of each of the embodiments described above, and various modifications can be made without departing from the spirit of the invention. The planar light source unit of the present invention can be applied to various display devices such as an illumination device used indoors or outdoors and a backlight device of a liquid crystal panel.

DESCRIPTION OF SYMBOLS 1 ... Planar light emission unit, 2 ... Translucent board | substrate, 3 ... 1st electrode layer (anode layer), 4 ... Organic electroluminescent light emitting layer, 5 ... 2nd electrode Layer (cathode layer), 7 ... auxiliary electrode,
10 ... planar light emitting device

Claims (2)

A translucent substrate;
A translucent first electrode layer formed on the substrate and having a substantially quadrangular shape as a whole, divided by diagonal segments thereof to form two substantially triangular shapes;
An auxiliary electrode having a smaller resistance value than the first electrode layer and provided along each of the triangular sides;
An organic EL light-emitting layer formed on the first electrode layer and having a substantially rectangular shape similar to the first electrode layer;
A second electrode layer formed on the organic EL light emitting layer;
A planar light-emitting unit comprising:   In the combination of the planar light emitting units according to claim 1 so as to be polymerized, among these planar light emitting units, the second electrode layer of the planar light emitting unit farthest from the light emitting surface side is made reflective. A planar light-emitting device, wherein the second electrode layer of another planar light-emitting unit is formed of a light-transmitting material.

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