JP5418328B2 - Organic EL panel - Google Patents

Description

  The present invention relates to an organic EL (electroluminescence) device, and more particularly to a COG type organic EL panel in which a driver IC is mounted on a support substrate.

  Conventionally, as an organic EL panel, for example, an organic layer having at least an organic light emitting layer includes an anode line (first electrode line) made of ITO (Indium Tin Oxide) or the like and a cathode line (second electrode) made of aluminum (Al) or the like. It is known that a plurality of organic EL elements sandwiched between lines) are formed on a supporting substrate made of a glass material as light emitting pixels to constitute a light emitting display portion (see, for example, Patent Document 1). Such an organic EL element emits light by injecting holes from the anode and injecting electrons from the cathode and recombining the holes and electrons in the light emitting layer.

  Further, as a method of mounting a driver IC for driving the organic EL element, a COG (Chip on Glass) form in which the driver IC is directly mounted on a support substrate is known (for example, see Patent Document 2). The COG type organic EL panel is excellent in that it can be reduced in size with respect to other mounting methods such as a TCP (Tape Carrier Package) type in which a driver IC is mounted on an FPC (Flexible Printed Circuit).

JP-A-8-315981 JP 2000-40585 A JP 2003-309237 A

  Since the COG type organic EL panel has a configuration in which the driver IC is directly mounted on the metal wiring (thickness of about 0.5 μm) formed on the support substrate, the thermal resistance becomes very large, and the heat radiation from the driver IC is performed. The temperature of the driver IC is likely to be high due to obstruction. As a result, the temperature of the driver IC may exceed the rated temperature, especially in organic EL panels that require high-luminance light emission, which are used for in-vehicle devices such as instruments, and the operation reliability at high temperatures may be reduced. There is a problem that there is.

  On the other hand, as a method for improving the heat dissipation efficiency of the driver IC, in Patent Document 3, in the liquid crystal display panel, a heat transfer member is provided between the back surface of the panel mounting portion mounted on the COG and the panel support structure frame. There is disclosed a technique in which the temperature rise is reduced by transferring heat from the IC or panel to the frame and dissipating the heat.

  However, a heat dissipation method using such a frame as a heat sink uses heat transfer in the vertical direction, and thickness is required to improve heat transfer efficiency. When applied to an organic EL panel, the organic EL panel and There has been a problem that the thickness of the organic EL module including the exterior is greatly increased, and the characteristics of the organic EL panel that are thin cannot be maintained.

  Therefore, in view of the above-described problems, the present invention can improve the heat radiation efficiency of the driver IC and improve the operation reliability of the driver IC at a high temperature while maintaining the thin shape in the COG type organic EL panel. An object of the present invention is to provide an organic EL panel.

In order to solve the above problems, the present invention provides a support substrate, a light emitting display unit formed by laminating at least a first electrode, an organic light emitting layer, and a second electrode on the support substrate, and mounting on the support substrate. A bottom emission type organic EL panel that emits light from the light emitting display unit from the support substrate side, and a driver IC that applies a drive current between the first and second electrodes. On the surface of the substrate opposite to the surface on which the driver IC is mounted, a heat radiating member facing the driver IC and diffusing heat generated from the driver IC in the direction of the surface of the support substrate, and reflecting external light A polarizing plate to be suppressed, and the heat dissipating member is formed thinner than the polarizing plate .

  As described above, according to the present invention, in the COG type organic EL panel, it is possible to improve the heat dissipation efficiency of the driver IC while maintaining the thin shape, and to obtain high reliability of the driver IC.

The top view which shows the organic electroluminescent panel which is embodiment of this invention. The side view which shows an organic electroluminescent panel same as the above. The principal part enlarged view of an organic electroluminescent panel same as the above. Sectional drawing which shows the organic EL element which shows an organic EL panel same as the above. The figure which shows the temperature measurement result of the Example and comparative example of this invention. The figure which shows the image which image | photographed the Example and comparative example of this invention.

  Hereinafter, an organic EL panel according to an embodiment of the present invention will be described with reference to the accompanying drawings. 1 and 2 are overall views of the organic EL panel, and FIGS. 3 and 4 are enlarged views of main parts of the organic EL panel. In the drawing, a part of each wiring described later is omitted.

  The support substrate 11 is an electrically insulating substrate made of a rectangular transparent glass material. On one surface of the support substrate 11, a light emitting display unit 12 and a driver IC 13 are provided. A circularly polarizing plate 14 and a heat dissipation member 15 are provided on the other surface of the support substrate 11 (the surface opposite to the surface on which the driver IC 13 is mounted). On the support substrate 11, an anode wiring 16 connected to each anode line of the light emitting display section 12 described later, a cathode wiring 17 connected to each cathode line of the light emitting display section 12 described later, and a driver IC 13 are connected to an external circuit. And an input wiring 18 for electrical connection. In addition, although the sealing member which covers the light emission display part 12 airtightly is arrange | positioned on the support substrate 11, the sealing member is abbreviate | omitted in FIG.1 and FIG.3.

  As shown in FIGS. 2 and 3, the light emitting display unit 12 includes a plurality of anode lines (first electrodes) 12a, an insulating film 12b, a partition wall 12c, an organic layer 12d, and a plurality of cathode lines. (Second electrode) 12e, and so-called passive comprising a plurality of light-emitting pixels (organic EL elements) mainly composed of portions where each anode line 12a and each cathode line 12e cross each other and sandwich the organic layer 12d. This is a matrix-type light emitting display portion. The present embodiment is a so-called bottom emission type organic EL panel that emits light emitted from the light emitting display unit 2 from the support substrate 1 side. Further, as shown in FIGS. 2 and 4, the light emitting display portion 12 is airtightly covered with a sealing member 12 f.

  The anode line 12a is made of a light-transmitting conductive material such as ITO. The anode lines 12a are formed so as to be substantially parallel to each other by a photolithography method or the like after the conductive material is formed in layers on the support substrate 11 by means such as vapor deposition or sputtering. Each anode line 12a is connected to each anode wiring 16 on one side of the end (the lower side in FIG. 1).

  The insulating film 12b is made of, for example, a polyimide-based electrically insulating material, and is formed so as to be positioned between the anode line 12a and the cathode line 12e, and prevents a short circuit between the electrode lines 12a and 12e. The insulating film 12b is formed with an opening 12b1 that defines each light emitting pixel and makes the outline clear. The insulating film 12b also extends between the cathode wiring 17 and the cathode line 12e, and has a contact hole 12b2 that connects each cathode wiring 17 and each cathode line 12e.

  The partition wall 12c is made of, for example, a phenol-based electrically insulating material, and is formed on the insulating film 12b. The partition wall 12c is formed by means such as a photolithography method so that the cross section thereof has a reverse taper shape with respect to the insulating film 12b. A plurality of partition walls 12c are formed at equal intervals in a direction orthogonal to the anode line 12a. The partition wall 12c has a structure in which the organic layer 12d and the cathode line 12e are divided when the organic layer 12d and the cathode line 12e are formed from above by a vapor deposition method, a sputtering method, or the like.

  The organic layer 12d is formed on the anode line 12a and includes at least an organic light emitting layer. In the present embodiment, the organic layer 12d is formed by sequentially laminating a hole injection layer, a hole transport layer, an organic light emitting layer, and an electron transport layer by means of vapor deposition or sputtering.

  The cathode line 12e is formed of a plurality of metallic conductive materials having higher conductivity than the anode line 12a such as aluminum (Al) and magnesium silver (Mg: Ag) so as to intersect the anode line 12a by means such as vapor deposition. It will be. Each cathode line 12e is connected to each cathode wiring 17 through a contact hole 12b2 provided in the insulating film 12b.

  The sealing member 12f is made of, for example, a glass material, and is disposed on the support substrate 1 via an adhesive 12g to house the light emitting display unit 12 in an airtight manner.

  The driver IC 13 constitutes a drive circuit that drives the light emitting display unit 12 to emit light, and includes a signal line drive circuit, a scanning line drive circuit, and the like. The driver IC 13 is mounted on the support substrate 11 according to the light emitting display unit 12 by COG mounting technology, and is electrically connected to each anode line 12a and each cathode line 12e via each anode wiring 16 and each cathode wiring 17. A drive current is applied between each anode line 12a and each cathode line 12e based on a drive signal from an external circuit.

  The circularly polarizing plate 14 is a plate-like light transmissive member formed by laminating a linearly polarizing plate and a birefringent plate, and suppresses reflection of external light. The circularly polarizing plate 14 is attached to the emission surface side of the support substrate 11 through an adhesive layer.

  The heat radiating member 15 is made of an adhesive sheet obtained by processing a material having higher thermal conductivity than the material of the support substrate 11 such as copper (Cu), aluminum (Al), or graphite, and the driver IC 13 of the support substrate 11 is mounted thereon. The driver IC 13 is disposed on the surface opposite to the surface facing the driver IC 13. In the present embodiment, the heat dissipation member 15 is attached to the emission surface side of the support substrate 11. As will be described later, in order to diffuse the heat generated from the driver IC 13 in the panel surface direction, the heat radiating member 15 is any one other than the support substrate 11 when the organic EL panel is modularized by being housed in a case. It shall not be in contact with any member. The heat dissipating member 15 is widely disposed in the panel surface direction so as to cover the non-light emitting region of the support substrate 11, and the area is desirably at least larger than the area of the driver IC 13. The thickness of the heat dissipation member 15 is appropriately set according to the use of the organic EL panel and the amount of heat generated by the driver IC 13, but more than the circularly polarizing plate 14 disposed on the same surface of the support substrate 11. By reducing the thickness, the total thickness of the organic EL panel can be suppressed, which is preferable.

  The anode wiring 16 is a wiring that connects the anode line 12a and the driver IC 13, and is made of, for example, a conductive material such as ITO, chromium (Cr), aluminum (Al), or the like, which is the same material as the anode line 12a, or a laminate of these conductive materials. Become. The anode wiring 16 is formed integrally with the anode line 12a on the support substrate 11, or is formed separately so as to be connected to the anode line 12a.

  The cathode wiring 17 is a wiring that connects the cathode line 12e and the driver IC 13, and is made of, for example, a conductive material such as ITO, chromium (Cr), or aluminum (Al), which is the same material as the anode line 12a, or a laminate of these conductive materials. Become. The cathode wiring 17 is a wiring formed by being routed alternately to the left and right with respect to each cathode line 12e on the side on the support substrate 11, and one end is connected to the cathode line 12e and the other end is connected to the driver IC 13. As shown in FIG. 3, the cathode wiring 17 has at least an end portion of the cathode line 12e connected to the cathode line 12e via the insulating film 12b so that it can be connected to the cathode line 12e via the contact hole 12b2. It is formed so as to be positioned below.

  The input wiring 18 is a wiring for electrically connecting the driver IC 13 and an external circuit. For example, a conductive material such as ITO, chromium (Cr) or aluminum (Al), which is the same material as the anode line 12a, or these conductive materials. It consists of a laminate of materials. The input wiring 18 is formed around the driver IC 13 on the support substrate 11, one end is connected to the driver IC 13, and the other end is connected to an FPC (not shown) via the ACF.

  The organic EL panel is configured by the above-described units.

  In such an organic EL panel, a heat radiating member 15 is arranged on the surface of the support substrate 11 opposite to the surface on which the driver IC 13 is mounted, facing the driver IC 13 and diffusing heat generated from the driver IC 13 in the surface direction of the support substrate 11. It is established. The area of the heat dissipation member 15 is larger than the area of the driver IC 13. The heat dissipation member 15 is disposed so as to cover the non-light emitting region of the support substrate 11.

  The main heat dissipation paths in this embodiment are as follows. As shown by the arrows in FIG. 2, most of the heat generated from the driver IC 13 is first transferred into the support substrate 11 and then conducted to the heat dissipation member 15. Since the heat radiating member 15 uses a material having a higher thermal conductivity than the material of the support substrate 11, heat is diffused throughout the heat radiating member 15. Furthermore, the heat diffused throughout the heat radiating member 15 is radiated to the outside from the heat radiating member 15 itself, and since the area of the heat radiating member 15 is larger than the area of the driver IC 13, the heat is diffused at a lower temperature than the heat radiating member 15. Conduction is also conducted in the direction of the edge of a certain support substrate 11 and diffused throughout the support substrate 11. That is, the heat dissipation path follows the surface direction of the support substrate 11 and diffuses the heat from the driver IC 13 in the surface direction of the support substrate 11, thereby improving the heat dissipation efficiency of the driver IC 13 and operating reliability of the driver IC 13 at high temperatures. Can be increased. Since there is no need to bring the heat dissipation member 15 into contact with members other than the support substrate 11, the thickness of the panel does not increase, and the characteristics of the organic EL panel that are thin can be maintained. Further, since the heat dissipating member 15 is arranged on the support substrate 11, even a thin driver IC 13 which is difficult to directly contact the heat dissipating member can efficiently dissipate heat.

Hereinafter, specific examples of the present invention will be described with further examples. As Example 1, a 2.7-inch type organic EL panel having a panel size of 76.1 × 28.1 mm, a graphite sheet manufactured by Otsuka Electric Co., Ltd. having a thickness of 0.13 mm and a width of 5 mm × 35 mm was used. What was affixed so that it might oppose the driver IC13 on the surface on the opposite side to the driver IC13 mounting surface of the support substrate 11 was produced. As Example 2, an organic EL panel was produced in the same manner as in Example 1 except that a graphite sheet made by Otsuka Electric Co., Ltd. having a thickness of 0.13 mm and a width of 5 mm × 70 mm was used as the heat radiating member 15. As Example 3, an organic EL panel was produced in the same manner as in Example 1 except that a graphite sheet manufactured by Otsuka Electric Co., Ltd. having a thickness of 0.25 mm and a width of 5 mm × 35 mm was used as the heat radiating member 15. As Example 4, an organic EL panel was produced in the same manner as in Example 1 except that a graphite sheet manufactured by Otsuka Electric Co., Ltd. having a thickness of 0.25 mm and a width of 5 mm × 70 mm was used as the heat dissipation member 15. As a comparative example, an organic EL panel was produced in the same manner as in Example 1 except that the heat dissipation member 15 was not provided. Then, as a method for evaluating the heat dissipation efficiency of each example and comparative example, each organic EL panel was turned on at a lighting rate of 100% (full lighting) with a luminance of 70 cd / m ² as a target value. The organic EL panel was photographed from the back side of the driver IC 13 (opposite side of the mounting surface) with an IR (infrared) camera, and the panel temperature was measured.

  FIG. 5 shows the temperature measurement results of each example and comparative example. The temperature increase ΔT with respect to the temperature before lighting in the comparative example was 36.2 ° C. On the other hand, the rising temperature ΔT of Comparative Example 1 was 24.8 ° C., and a temperature increase reducing effect of −11.4 ° C. was obtained with respect to the Comparative Example. In Comparative Example 2, the rising temperature ΔT was 21.8 ° C., and a temperature increase reducing effect of −14.4 ° C. was obtained with respect to the Comparative Example. In Comparative Example 3, the temperature rise ΔT was 23.9 ° C., and a temperature rise reduction effect of −12.3 ° C. was obtained with respect to the Comparative Example. In Comparative Example 4, the temperature increase ΔT was 19.2 ° C., and a temperature increase reduction effect of −17 ° C. was obtained with respect to the Comparative Example. It can be seen that if the material is the same, the heat dissipation efficiency is improved if the thickness and area of the heat dissipation member 15 are increased. In each embodiment, the heat radiation member 15 has the same width of 5 mm. However, by increasing the width according to the non-light emitting region of the support substrate 11, higher heat radiation efficiency can be obtained. Moreover, FIG. 6 shows the image which image | photographed each Example and the comparative example. In FIG. 6, there is a driver IC 13 at the center of each image, and the temperature is highest. In a portion excluding the driver IC 13 of each image, a portion where the color is lighter is a portion where the temperature is higher and a portion where the color is darker is a portion where the temperature is lower. In the comparative example shown in FIG. 6A, it can be seen that the thermal diffusion in the surface direction of the support substrate 11 is not sufficient and the temperature of the driver IC 13 is high. On the other hand, in each of the examples shown in FIGS. 6B to 6E, heat is widely diffused in the surface direction of the support substrate 11 with respect to the comparative example, and the heat is efficiently dispersed over the entire panel. It can be seen that the temperature rise of the driver IC 13 is suppressed. From the above evaluation results, it is clear that the present invention has a sufficient effect.

  The present invention is suitable for a COG type organic EL panel.

11 Support substrate 12 Light-emitting display part 12a Anode line (first electrode)
12b Insulating film 12c Partition 12d Organic layer 12e Cathode line (second electrode)
12f Sealing member 13 Driver IC
14 circularly polarizing plate 15 heat dissipation member 16 anode wiring 17 cathode wiring 18 input wiring

Claims (3)

A support substrate;
A light emitting display unit formed by laminating at least a first electrode, an organic light emitting layer, and a second electrode on the support substrate; and a driving current applied between the first and second electrodes mounted on the support substrate. A bottom emission type organic EL panel that emits light from the light emitting display unit from the support substrate side ,
On the surface of the support substrate opposite to the surface on which the driver IC is mounted, a heat radiating member facing the driver IC and diffusing heat generated from the driver IC in the surface direction of the support substrate ; An organic EL panel comprising: a polarizing plate that suppresses reflection; and the heat dissipating member being formed thinner than the polarizing plate . The organic EL panel according to claim 1, wherein an area of the heat dissipation member is larger than an area of the driver IC. The organic EL panel according to claim 1, wherein the heat dissipation member is disposed so as to cover a non-light emitting region of the support substrate.

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