JP2005317346A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device maintaining a good display performance for a long time, and reduced in size and manufacturing cost. <P>SOLUTION: The display device is equipped with an array substrate 100 and a sealing substrate 200 to seal the array substrate 100. The sealing substrate 200 is equipped with a heat conduction layer 250 having a higher thermal conductivity than the sealing substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display device, and more particularly to an organic electroluminescence display device including a plurality of self-light emitting elements.

  In recent years, organic electroluminescence (EL) display devices have attracted attention as flat display devices. Since this organic EL display device is a self-luminous element, it has a wide viewing angle, can be thinned without requiring a backlight, has low power consumption, and has a high response speed. ing.

  Because of these characteristics, organic EL display devices are attracting attention as potential candidates for next-generation flat display devices that can replace liquid crystal display devices. An organic EL display device is configured to include an array substrate configured by arranging organic EL elements having an organic active layer containing an organic compound having a light emitting function between an anode and a cathode in a matrix. .

  In such an organic EL display device, there is a problem of extending the life of the organic EL element.

  One of the major causes of deterioration of the organic EL element is the influence of heat. This heat is inevitably generated as long as voltage and current are applied for light emission. In addition, the degree of deterioration in luminance in each organic EL element varies depending on the state of heat generation or heat removal in the screen of the organic EL display device. For this reason, in-plane variation occurs in the luminance deterioration, and as a result, the display quality is lowered.

  In order to solve this, a technique of providing a heat dissipation layer on a plastic substrate that constitutes an array substrate is disclosed (for example, refer to Patent Document 1). Such a heat dissipation layer is formed in common for a plurality of pixels. For this reason, when the heat dissipation layer is formed of a conductive material, it is necessary to provide an insulating layer between the heat dissipation layer and the organic EL element of each pixel in order to prevent a short circuit between the pixels. Although depending on the film formation accuracy of the insulating layer, a considerable film thickness is required to reliably insulate between the heat dissipation layer and the organic EL element. Therefore, the thickness of the entire array substrate is increased, and as a result, the thickness of the organic EL display device is also increased, which is disadvantageous for thinning. In addition, a material and a manufacturing process for providing the insulating layer are required to form the insulating layer, which is disadvantageous in terms of manufacturing cost.

Furthermore, when the heat dissipation layer is formed of an insulating material such as a glass material or a ceramic material, the insulating material generally does not have a sufficiently high thermal conductivity, and heat is entirely applied within the screen of the organic EL display device. It is difficult to diffuse uniformly. In particular, the heat generated at the center of the screen is difficult to diffuse and tends to be locally hot. For this reason, the organic EL element arrange | positioned at the center part of a screen will deteriorate earlier than the thing of a peripheral part, and will reduce display quality remarkably.
JP 2002-63985 A

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a display device capable of maintaining good display performance over a long period of time. Another object of the present invention is to provide a display device that can be thinned and can be reduced in manufacturing cost.

A display device according to a first aspect of the present invention includes:
In a display area for displaying an image, a first electrode formed in an independent island shape for each pixel arranged in a matrix, and a second electrode arranged opposite to the first electrode and formed in common for all pixels An array substrate comprising: an organic active layer held between the first electrode and the second electrode;
A sealing substrate for sealing the array substrate,
The sealing substrate includes a heat conductive layer having a higher thermal conductivity than the sealing substrate.

A display device according to a second aspect of the present invention provides:
In a display area for displaying an image, a first electrode formed in an independent island shape for each pixel arranged in a matrix, and a second electrode arranged opposite to the first electrode and formed in common for all pixels An array substrate comprising: an organic active layer held between the first electrode and the second electrode;
A sealing substrate for sealing the array substrate;
A spacer disposed between the array substrate and the sealing substrate,
The spacer has a higher thermal conductivity than the sealing substrate.

  According to the present invention, it is possible to provide a display device capable of maintaining good display performance over a long period of time. In addition, according to the present invention, it is possible to provide a display device that can be reduced in thickness and reduced in manufacturing cost.

  Hereinafter, a display device and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a self-luminous display device such as an organic EL (electroluminescence) display device will be described as an example of the display device.

(First embodiment)
As shown in FIGS. 1 and 2, the organic EL display device 1 includes an array substrate 100 having a display area 102 for displaying an image, and a sealing substrate 200 for sealing at least the display area 102 of the array substrate 100. Composed. The display area 102 of the array substrate 100 is configured by a plurality of pixels PX (R, G, B) arranged in a matrix.

  Each pixel PX (R, G, B) is supplied via a pixel switch 10 and a pixel switch 10 having a function of electrically separating an on-pixel and an off-pixel and holding a video signal to the on-pixel. The driving transistor 20 supplies a desired driving current to the display element based on the video signal, and the storage capacitor element 30 holds the gate-source potential of the driving transistor 20 for a predetermined period. The pixel switch 10 and the drive transistor 20 are constituted by, for example, thin film transistors, and here, polysilicon is used for their semiconductor layers.

  Each pixel PX (R, G, B) includes an organic EL element 40 (R, G, B) as a display element. That is, the red pixel PXR includes an organic EL element 40R that emits red light, the green pixel PXG includes an organic EL element 40G that emits green light, and the blue pixel PXB includes an organic EL element 40B that emits blue light. I have.

  The various organic EL elements 40 (R, G, B) basically have the same structure. That is, the organic EL element 40 is arranged in a matrix and is formed in an independent island shape for each pixel PX, and a first electrode 60 that is opposed to the first electrode 60 and is formed in common for all the pixels PX. The two electrodes 66 and the organic active layer 64 held between the first electrode 60 and the second electrode 66 are configured.

  The array substrate 100 includes a plurality of scanning lines Ym (m = 1, 2,...) Arranged along the row direction of the pixels PX (that is, the Y direction in FIG. 1), and a direction substantially orthogonal to the scanning lines Ym (that is, A plurality of signal lines Xn (n = 1, 2,...) Arranged along the X direction in FIG. 1 and a power supply line Pm (for supplying power to the first electrode 60 side of the organic EL element 40). m = 1, 2,...). The power supply line Pm is connected to a first electrode power line (not shown) arranged around the display area 102. The second electrode 66 side end of the organic EL element 40 is connected to a second electrode power supply line (not shown) that is arranged around the display area 102 and supplies a common potential, here, a ground potential.

  The array substrate 100 has a scanning line driving circuit 107 that supplies a scanning signal to the scanning line Ym and a signal line driving circuit 108 that supplies a video signal to the signal line Xn in a peripheral area 104 along the outer periphery of the display area 102. And. All the scanning lines Ym are connected to the scanning line driving circuit 107. All signal lines Xn are connected to the signal line driving circuit 108.

  Here, the pixel switch 10 is disposed in the vicinity of the intersection between the scanning line Ym and the signal line Xn. The pixel switch 10 has a gate electrode connected to the scanning line Ym, a source electrode connected to the signal line Xn, and a drain electrode connected to one electrode constituting the storage capacitor 30 and the gate electrode of the drive transistor 20. The source electrode of the drive transistor 20 is connected to the other electrode constituting the storage capacitor element 30 and the power supply line Pm, and the drain electrode is connected to the first electrode 60 of the organic EL element 40.

  As shown in FIG. 2, the array substrate 100 includes an organic EL element 40 disposed on the wiring substrate 120. Note that the wiring substrate 120 is formed on a light-transmitting insulating support substrate such as a glass substrate or a plastic sheet, the pixel switch 10, the driving transistor 20, the storage capacitor element 30, the scanning line driving circuit 107, and the signal line driving circuit 108. It is assumed that the apparatus is configured to include various wirings (scanning lines, signal lines, power supply lines, etc.).

  The first electrode 60 constituting the organic EL element 40 is disposed on the insulating film on the surface of the wiring substrate 120. Here, the first electrode 60 is formed of a light-transmitting conductive member such as ITO (Indium Tin Oxide) or IZO (Indium Zinc Oxide), and functions as an anode.

  The organic active layer 64 includes an organic compound having at least a light emitting function, and may be configured by a three-layer stack of a hole buffer layer formed in common for each color, an organic light emitting layer formed for each color, and an electron buffer layer, It may be composed of two layers or a single layer functionally combined. For example, the hole buffer layer is disposed between the anode and the organic light emitting layer, and is formed of a thin film such as an aromatic amine derivative, a polythiophene derivative, or a polyaniline derivative. The organic light emitting layer is formed of an organic compound having a light emitting function that emits red, green, or blue light. This organic light emitting layer is constituted by a thin film such as PPV (polyparaphenylene vinylene), a polyfluorene derivative, or a precursor thereof when, for example, a polymer light emitting material is employed.

  The second electrode 66 is disposed on the organic active layer 64 in common with each organic EL element 40. The second electrode 66 is formed of a metal film having an electron injection function such as Ca (calcium), Al (aluminum), Ba (barium), Ag (silver), Yb (ytterbium), and functions as a cathode. Yes. The second electrode 66 may have a two-layer structure in which the surface of a metal film functioning as a cathode is covered with a cover metal. The cover metal is made of aluminum, for example. Further, the surface of the second electrode 66 may be coated with a hygroscopic material as a desiccant. That is, when the organic EL element 40 is exposed to moisture, its light emission characteristics are rapidly deteriorated. For this reason, in order to protect the organic EL element 40 from moisture, a desiccant may be disposed on the second electrode 66 corresponding to the surface thereof.

  Further, the array substrate 100 includes a partition wall 70 that separates the pixels PX (R, G, B) in the display area 102. The partition walls 70 are arranged in a lattice shape along the periphery of the first electrode 60. The partition wall 70 is formed of a resin material. For example, the partition wall 70 is formed of a lyophilic organic material and a liquid-phobic organic material disposed on the first insulating layer. The second insulating layer is laminated.

  On the other hand, the sealing substrate 200 is configured by a glass substrate, a plastic sheet, or the like. The sealing substrate 200 includes a heat conductive layer 250. This thermal conductive layer 250 has a higher thermal conductivity than the sealing substrate 200.

  The array substrate 100 and the sealing substrate 200 are sealed with a frame-shaped sealing material 400 that surrounds the display area 102 in a state where a predetermined gap is formed, and a sealed space is formed in the predetermined gap. This sealed space is filled with an inert gas such as nitrogen gas. In addition, a desiccant is disposed inside the sealed space, and is maintained in a dry state that does not adversely affect the organic EL element 40.

  In the organic EL display device 1 of the bottom emission type configured as described above, in the organic EL element 40 of each pixel PX, electrons and the organic active layer 64 sandwiched between the first electrode 60 and the second electrode 66 are stored. Excitons are generated by injecting holes and recombining them, and light is emitted by light emission of a predetermined wavelength generated when the excitons are deactivated. Here, EL light emission is emitted from the lower surface side of the array substrate 100, that is, the first electrode 60 side.

  According to the organic EL display device 1 as described above, the heat conduction layer 250 provided on the sealing substrate 200 can efficiently and uniformly diffuse the heat generated inside the device over the entire screen. That is, the heat generated from each organic EL element 40 during operation is transferred to the heat conduction layer 250 through the inert gas filled in the predetermined gap. The heat conductive layer 250 has a high thermal conductivity, and dissipates the transferred heat throughout the sealing substrate 200 to dissipate heat. Therefore, it is possible to prevent a local high temperature such as the center of the screen from being driven while driving each pixel. Thereby, it can suppress that some organic EL elements 40 deteriorate early. For this reason, the influence of heat can be alleviated, the life of the organic EL element 40 can be extended, the degree of luminance deterioration can be made uniform within the screen, and good display performance can be maintained over a long period of time. Is possible.

  Further, since the thermal conductive layer 250 is provided on the sealing substrate 200 side, an insulating layer for insulating the organic L element and the heat dissipation layer of each pixel becomes unnecessary, and the entire device can be thinned. Further, not only the material for forming the insulating layer is unnecessary, but also a manufacturing process for providing the insulating layer is not required, and the manufacturing cost can be reduced.

  Specifically, the heat conductive layer 250 desirably has a heat conductivity of 10 W / m · K or more (at room temperature). If the thermal conductive layer 250 has such a thermal conductivity, regardless of the material of the sealing substrate 200 (thermal conductivity of glass substrate: 0.55 to 0.75 W / m · K, plastic substrate ( For example, a polycarbonate substrate) has a thermal conductivity of 0.2 W / m · K) and a thermal conductivity higher than that of the sealing substrate 200, and the above-described effects can be sufficiently exhibited.

  Further, as shown in FIG. 2, the heat conductive layer 250 is integrally formed on a surface of the sealing substrate 200 facing the array substrate 100. Here, the heat conductive layer 250 may be provided only on the surface (inner surface) of the sealing substrate 200 facing the array substrate 100, only on the outer surface of the sealing substrate 200, or on both surfaces of the sealing substrate. The heat generation source in particular is the organic EL element 40 provided on the array substrate 100 side. For this reason, it is desirable to provide the heat conductive layer 250 on the surface (inner surface) facing the array substrate 100, whereby the heat generated from the organic EL element 40 can be efficiently diffused.

  In addition, by providing the heat conductive layer 250 on the sealing substrate 200 side, even if a wet process is introduced to form the heat conductive layer 250, the organic EL element 40 on the array substrate 100 side is exposed to moisture. In other words, the performance degradation of the organic EL element 40 can be prevented.

  Further, the heat conductive layer 250 is formed to extend from the display area 102 to the outside thereof. That is, as shown in FIG. 2, the heat conductive layer 250 is formed on the outside from the inside of the sealing region (here, the sealing material arrangement region) of the array substrate and the sealing substrate, and outside the sealing material 400 (that is, the sealing material is sealed). It extends to the periphery of the stationary substrate. For this reason, the heat generated in the display area 102 can be effectively dissipated to the outside.

  Such a heat conductive layer 250 is formed of, for example, a metal material. Here, as a metal material, silver (Ag), gold (Au), copper (Cu), aluminum (Al), beryllium (Be), magnesium (Mg), molybdenum (Mo), nickel (Ni), tungsten ( Metal materials such as W), chromium (Cr), iron (Fe), and silicon (Si), or alloys thereof are applicable. When such a metal material is applied, the heat conductive layer 250 is formed on the sealing substrate by a vapor deposition method (including a sputtering method, an electron beam method, a heat vapor deposition method, an ion plating method, etc.), a CVD method, a plating method, or the like. The film is formed on the substrate 200 with a predetermined film thickness. Note that, when a resin material is applied as the sealing substrate 200, a method of forming the heat conductive layer 250 using a metal material is not so practical because it is restricted by a film formation temperature or the like. That is, when the heat conductive layer 250 is formed of such a metal material, it is desirable to apply a glass substrate advantageous in heat resistance as the sealing substrate 200.

  Further, the heat conductive layer 250 may be formed of a resin material containing conductive particles. As the conductive particles, metal fine particles made of various metal materials as described above, carbon particles, semiconductor fine particles, and the like are applicable. As the resin material, polymer materials such as polyester, polyvinyl, polystyrene, nylon, polysiloxane, polyether, and epoxy are applicable. When a material in which the above-described conductive particles are dispersed is applied to such a resin material, the heat conductive layer 250 is formed on the sealing substrate 200 with a predetermined film thickness by a photolithography method, a printing method, or the like.

  Further, the heat conductive layer 250 may be formed of a conductive polymer material. As the conductive polymer material, a polymer material having conductivity such as polyaniline, polyfluorene, polythiophene or the like can be applied, and a material obtained by adding the above-described conductive particles to these conductive polymer materials is also applicable. It is. When such a conductive polymer material is applied, the heat conductive layer 250 is formed with a predetermined thickness on the sealing substrate 200 by a photolithography method, a printing method, or the like.

  The film thickness of the heat conductive layer 250 is preferably thick, but if the film thickness is at least 0.5 μm or more, thermal diffusion performance can be ensured. In addition, the upper limit of the film thickness of the heat conductive layer 250 is desirably set to an extent that does not hinder thinning of the entire apparatus, and is preferably set to 100 μm or less.

  As a specific pattern of the heat conductive layer 250, for example, as shown in FIG. 3, a solid pattern formed on the inner surface of the sealing substrate 200 with a substantially uniform film thickness and at least the same shape as the display area 102 is applied. Is possible. Further, as the pattern of the heat conductive layer 250, as shown in FIG. 4, a stripe pattern formed on the inner surface of the sealing substrate 200 with a substantially uniform film thickness and at least the outer shape equivalent to the display area 102 is also applicable. is there.

  As described above, by selectively forming the heat conductive layer 250 having a high thermal conductivity on the sealing substrate 200, heat can be uniformly and efficiently removed over the entire surface of the organic EL display device. Therefore, it is possible to provide a display device that can maintain good display performance over a long period of time. Further, it is possible to provide a display device that can be thinned and can be manufactured at a reduced cost.

  In the first embodiment described above, the bottom emission type organic EL display device has been described as an example, but the present invention can also be applied to a top emission type. That is, a light-transmitting substrate is applied as the sealing substrate 200, and a light-transmitting material such as ITO (Indium Tin Oxide) or IZO (Indium Zinc) is used as the heat conductive layer 250. By applying a light-transmitting conductive member such as oxide), it is possible to emit EL light from the upper surface side of the array substrate 100, that is, the sealing substrate 200 side. Such a top emission method has an advantage that a large aperture ratio can be secured without being influenced by the influence of the circuit layout on the wiring substrate 120, and high luminance can be obtained even with the same driving power as the bottom emission method.

(Second Embodiment)
Next, a second embodiment will be described. The organic EL display device according to the second embodiment has basically the same structure as that of the first embodiment described above, and it goes without saying that the same effects as those of the first embodiment described above can be obtained. A structure different from the first embodiment is that a spacer 300 for forming a predetermined gap between the array substrate 100 and the sealing substrate 200 is provided as shown in FIG.

  The spacer 300 is integrally formed on the surface of the sealing substrate 200 facing the array substrate 100. The spacer 300 is formed of a resin material and is formed at a predetermined height on the sealing substrate 200 by a photolithography method, a printing method, or the like. When the array substrate 100 and the sealing substrate 200 are sealed, the spacer 300 on the sealing substrate 200 side is a surface layer on the array substrate 100 side, such as the second electrode 66 (or cover metal, desiccant, protective film, etc.). ) To form a predetermined gap.

  According to the organic EL display device 1 as described above, the heat conduction layer 250 provided on the sealing substrate 200 can efficiently and uniformly diffuse the heat generated inside the device over the entire screen. That is, the heat generated from each organic EL element 40 during operation is transferred to the heat conduction layer 250 through the inert gas filled in the predetermined gap. At this time, heat generated from each organic EL element 40 during operation is also transmitted to the heat conductive layer 250 through the spacer 300 in contact with the organic EL element 40. The heat transmitted to the heat conductive layer 250 in this manner is diffused and dissipated throughout the sealing substrate 200. Therefore, the spacer 300 can be used as an effective path for heat dissipation, and heat can be removed more efficiently than in the first embodiment.

  In addition, since the spacer 300 is arranged on the sealing substrate 200 side, even if a wet process is introduced to form the spacer 300, the organic EL element 40 on the array substrate 100 side is not exposed to moisture, The performance deterioration of the organic EL element 40 can be prevented.

  Furthermore, by arranging the spacers 300, even when the substrate size is increased as the screen size is increased, each substrate can be prevented from being damaged when the array substrate 100 and the sealing substrate 200 are bent. In addition, the organic EL element 40 can be prevented from being destroyed by the contact of each substrate.

  Furthermore, by providing the spacer 300, a predetermined gap can be maintained between the array substrate 100 and the sealing substrate 200, and the sealing substrate can be used even when stress is applied to any of the substrates. Short-circuiting of the organic EL element 40 between a plurality of pixels through 200 can be prevented.

  Specifically, for example, as shown in FIG. 6, the heat conductive layer 250 is formed on the inner surface of the sealing substrate 200 with a substantially uniform film thickness and at least the shape equivalent to the display area 102, and corresponds to the spacer 300. The spacer 300 is formed at a height higher than the thickness of the heat conductive layer 250. The arrangement density of the spacers 300 (the number of spacers arranged per unit area) is appropriately set according to the required support strength and the like.

  When the heat conductive layer 250 and the spacer 300 are integrally formed on the surface of the sealing substrate 200 facing the array substrate 100, the heat conductive layer 250 is preferably formed of a material having a light shielding property. Such a structure can be formed by the following manufacturing method.

  That is, as shown in FIG. 7A, first, a heat conductive layer 250 having a predetermined pattern is formed on one main surface 200A of the sealing substrate 200 using a material having high thermal conductivity and high light shielding properties. To do. Then, as shown in FIG. 7B, a photosensitive resin material 300 'is applied to the entire main surface 200A side of the sealing substrate 200 on which the heat conductive layer 250 is formed. At this time, a negative photosensitive resin material (for example, an ultraviolet curable resin material) in which the exposed portion is polymerized and cured is applied. Then, the photosensitive resin material 300 ′ is exposed (for example, with ultraviolet rays) from the other main surface 200 </ b> B side of the sealing substrate 200. At this time, the heat conductive layer 250 previously formed on the main surface 200A serves as a mask, and is applied directly to the photosensitive resin material (that is, the main surface 200A of the sealing substrate 200) where the heat conductive layer 250 is not formed. Only the photosensitive resin material) is selectively exposed. Then, as shown in FIG. 7C, the exposed photosensitive resin material is developed and further baked to form the sealing substrate 200 integrally including the heat conductive layer 250 and the spacer 300. The

  By forming by such a method, a photoresist or a photomask for patterning becomes unnecessary, the manufacturing process is simplified, the manufacturing cost can be reduced, and the manufacturing time can be shortened.

  As described above, the thermal conductive layer 250 having a high thermal conductivity is selectively formed on the sealing substrate 200, and the spacer 300 that forms a predetermined gap between the array substrate 100 and the sealing substrate 200 is disposed. Thus, heat can be removed uniformly and efficiently over the entire surface of the organic EL display device. Therefore, it is possible to provide a display device that can maintain good display performance over a long period of time. Further, it is possible to provide a display device that can be thinned and can be manufactured at a reduced cost.

  In the second embodiment described above, the bottom emission organic EL display device has been described as an example, but the present invention can also be applied to a top emission method. That is, a light-transmitting substrate is applied as the sealing substrate 200, and a light-transmitting material is applied as the spacer 300. The heat conductive layer 250 is configured in a pattern having an opening corresponding to the partition wall 70, and the heat dissipation spacer is disposed so as to cover the opening (substantially light emitting portion) of the pixel, so that the EL light emission is emitted from the array substrate. It is also possible to emit light from the upper surface side of 100, that is, the sealing substrate 200 side.

(Third embodiment)
Next, a third embodiment will be described. As shown in FIGS. 1 and 8, the organic EL display device according to the third embodiment includes an array substrate 100 having a display area 102 for displaying an image, and sealing that seals at least the display area 102 of the array substrate 100. And a substrate 200. The display area 102 of the array substrate 100 is configured by a plurality of pixels PX (R, G, B) arranged in a matrix.

  The structure of the array substrate 100 and the structure of each pixel PX (R, G, B) are as described in the first embodiment, and the structure of the organic EL element 40 disposed in each pixel is also the same as that in the first embodiment. As explained. On the other hand, the sealing substrate 200 is configured by an insulating substrate having light transparency such as a glass substrate or a plastic sheet.

  The organic EL display device 1 according to the third embodiment includes a spacer 300 disposed between the array substrate 100 and the sealing substrate 200. The spacer 300 has a higher thermal conductivity than the sealing substrate 200.

  When sealing the array substrate 100 and the sealing substrate 200 described above, the spacer 300 on the sealing substrate 200 side is a surface layer on the array substrate 100 side, such as the second electrode 66 (or cover metal, desiccant, protective film, etc.). ) To form a predetermined gap. The sealed space formed in the predetermined gap is filled with an inert gas such as nitrogen gas. In addition, a desiccant is disposed inside the sealed space, and is maintained in a dry state that does not adversely affect the organic EL element 40.

  According to such an organic EL display device 1, the heat generated inside the device can be efficiently diffused uniformly throughout the screen by the spacer 300. That is, the heat generated from each organic EL element 40 during operation is transmitted to the spacer 300 for forming a predetermined gap. The spacer 300 has a high thermal conductivity and dissipates the transferred heat throughout the sealing substrate 200 to dissipate heat. Therefore, it is possible to prevent a local high temperature such as the center of the screen from being driven while driving each pixel. Thereby, it can suppress that some organic EL elements 40 deteriorate early. For this reason, the influence of heat can be alleviated, the life of the organic EL element 40 can be extended, the degree of luminance deterioration can be made uniform within the screen, and good display performance can be maintained over a long period of time. Is possible.

  Specifically, the spacer 300 desirably has a thermal conductivity of 10 W / m · K or more (at room temperature). If the spacer 300 has such a thermal conductivity, regardless of the material of the sealing substrate 200 (thermal conductivity of the glass substrate: 0.55 to 0.75 W / m · K, plastic substrate (for example, polycarbonate The thermal conductivity of the manufactured substrate) is 0.2 W / m · K), which is higher than that of the sealing substrate 200, and the effects as described above can be sufficiently exhibited.

  The spacer 300 is integrally formed on the surface of the sealing substrate 200 facing the array substrate 100. This eliminates the need for an insulating layer for insulating the organic L element and the heat dissipation layer of each pixel, and enables the entire device to be thinned. Further, not only the material for forming the insulating layer is unnecessary, but also a manufacturing process for providing the insulating layer is not required, and the manufacturing cost can be reduced.

  Furthermore, by providing the spacer 300 on the sealing substrate 200 side, even if a wet process is introduced to form the spacer 300, the organic EL element 40 on the array substrate 100 side is not exposed to moisture, The performance deterioration of the organic EL element 40 can be prevented.

  As shown in FIG. 8, the spacer 300 is integrally formed only on the surface (inner surface) of the sealing substrate 200 that faces the array substrate 100, but the spacer 300 faces the sealing substrate 200 of the array substrate 100. May be formed integrally only on the surface to be mounted, may be formed integrally on the inner surfaces of both substrates, or may be sandwiched between the inner surfaces of both substrates without being formed integrally on both substrates. May be.

  Such a spacer 300 is formed of, for example, a metal material. Here, as a metal material, silver (Ag), gold (Au), copper (Cu), aluminum (Al), beryllium (Be), magnesium (Mg), molybdenum (Mo), nickel (Ni), tungsten ( Metal materials such as W), chromium (Cr), iron (Fe), and silicon (Si), or alloys thereof are applicable. When such a metal material is applied, the spacer 300 is formed on the sealing substrate 200 by an evaporation method (including a sputtering method, an electron beam method, a heating evaporation method, an ion plating method, or the like), a CVD method, a plating method, or the like. Formed at a predetermined height.

  Further, the spacer 300 may be formed of a resin material containing conductive particles. As the conductive particles, metal fine particles made of various metal materials as described above, carbon particles, semiconductor fine particles, and the like are applicable. As the resin material, polymer materials such as polyester, polyvinyl, polystyrene, nylon, polysiloxane, polyether, and epoxy are applicable. In the case where a material in which the above-described conductive particles are dispersed is applied to such a resin material, the spacer 300 is formed on the sealing substrate 200 at a predetermined height by a photolithography method, a printing method, or the like.

  Further, the spacer 300 may be formed by forming with a conductive polymer material. As the conductive polymer material, a polymer material having conductivity such as polyaniline, polyfluorene, polythiophene or the like can be applied, and a material obtained by adding the above-described conductive particles to these conductive polymer materials is also applicable. It is. Furthermore, a material in which glass particles are mixed into conductive particles such as a plating paste is also applicable. When such a conductive polymer material is applied, the spacer 300 is formed at a predetermined height on the sealing substrate 200 by a photolithography method, a printing method, or the like.

  As a specific pattern of the spacer 300, for example, as shown in FIG. 9, the spacer 300 is arranged at a predetermined arrangement density on the inner surface of the sealing substrate 200. The arrangement density of the spacers 300 is appropriately set according to necessary thermal conductivity, necessary support strength, and the like.

  As described above, by selectively forming the spacer 300 having a high thermal conductivity on the sealing substrate 200, heat can be uniformly and efficiently removed over the entire surface of the organic EL display device. Therefore, it is possible to provide a display device that can maintain good display performance over a long period of time. Further, it is possible to provide a display device that can be thinned and can be manufactured at a reduced cost.

  In the third embodiment described above, the bottom emission organic EL display device has been described as an example, but the present invention can also be applied to a top emission method. That is, by applying a light-transmitting substrate as the sealing substrate 200 and disposing the spacer 300 so as not to cover the opening (substantially light emitting portion) of the pixel, the EL light emission is emitted from the array substrate 100. It is also possible to emit light from the upper surface side, that is, the sealing substrate 200 side.

Example 1
A method of manufacturing the organic EL display device in Example 1 will be described. The display area 102 has a size of 6 inches diagonal, and the definition is 150 ppi (pixel per inch).

  First, the wiring board 120 is prepared. That is, a 0.7 mm thick insulating substrate having light transmittance is prepared. Then, processes such as formation of a metal film and an insulating film and patterning are repeated, and in addition to the pixel switch 10, the driving transistor 20, the storage capacitor element 30, the scanning line driving circuit 107, and the signal line driving circuit 108 on the insulating substrate. Then, the wiring substrate 120 on which various wirings such as the signal line Xn, the scanning line Ym, and the power supply line Pm are also formed.

  Subsequently, a first electrode 60 made of a conductive material having optical transparency, for example, ITO (indium tin oxide) is formed in each pixel PX. When forming the ITO film, the average value of the surface unevenness difference was controlled to 50 angstroms or less by controlling the temperature of sputtering. Then, a partition wall 70 having a structure in which a lyophilic first insulating layer, a lyophobic second insulating layer, or the like is laminated on the wiring substrate 120 so as to surround the first electrode 60 is formed.

  Subsequently, an organic active layer 64 including a hole buffer layer and the like in addition to the organic light emitting layer is formed in each pixel. The organic active layer 64 is formed by, for example, applying a conductive polymer PEDOT (polyethylenedioxythiophene), which forms a hole buffer layer, an organic light emitting layer, or the like, and a polymer light emitting polymer material using a piezoelectric inkjet nozzle, It is formed by applying a drying process.

  Subsequently, the second electrode 66 is formed on the entire surface of the array substrate 100. That is, the second electrode is disposed on the organic active layer 64 and on the partition wall 70 protruding from the organic active layer 64, and is provided in common for all pixels. Here, barium (Ba) as the cathode material and silver (Ag) as the cover metal were continuously deposited. At this time, the deposition rate of barium was set to 5 angstrom / sec in the first half, 20 angstrom / sec in the latter half, and the deposition rate of silver was set to 50 angstrom / sec. Thereby, the organic EL element 40 of each pixel PX is formed.

  Subsequently, the sealing substrate 200 is prepared. That is, as the sealing substrate 200, a 0.7 mm thick glass substrate having light transmittance is prepared. And silver (Ag) is vapor-deposited through the mask of a predetermined pattern on one main surface of this sealing substrate 200, and the heat conductive layer 250 of a pattern as shown in FIG. 3 is formed.

  Subsequently, an ultraviolet curable sealant 400 is printed along the outer periphery of the main surface of the sealing substrate 200 on which the heat conductive layer 250 is formed. In an inert gas atmosphere, the array substrate 100, the sealing substrate 200, and the like are printed. Crimp and paste together. Thereby, the organic EL element 40 is enclosed in the sealed space of an inert gas atmosphere. Thereafter, the sealing material 400 is cured by irradiating with ultraviolet rays. Thereafter, external connection terminals were further mounted by OLB (outer lead bonding) to manufacture an organic EL display device.

In the organic EL display device 1 manufactured as described above, the life test was performed under the condition of the initial luminance of 100 Cd / m ² by adjusting the amount of drive current flowing through the organic EL element 40 of each pixel. As a result, the lifetime in which the luminance of the organic EL element 40 is halved is about 20,000 hours, and it was confirmed that sufficient life characteristics can be obtained.

(Example 2)
A method of manufacturing the organic EL display device in Example 2 will be described. Here, the array substrate 100 having the same structure as that of the first embodiment is used. When forming the ITO film, the film quality was improved by annealing at 220 ° C. for 1 hour after sputtering so that the average value of the surface unevenness difference was 100 angstroms or less. After forming the partition wall 70, TPD (N, N′biphenyl N, N′bismethylphenyl-biphenyldiamine) as a hole bonding material and Alq3 (trishydroxyquinone aluminum) as an organic light emitting layer material are continuously deposited on ITO. did. Further, magnesium (Mg) as a cathode material and silver (Ag) as a cover metal were continuously deposited. At this time, magnesium (Ag) and magnesium (Mg) were alternately deposited after forming a magnesium film having a thickness of 50 angstroms to form a 100 angstrom alloy, and then a silver (Ag) film having a thickness of 500 angstroms was further formed.

  Subsequently, the sealing substrate 200 is prepared. That is, as the sealing substrate 200, a 0.7 mm thick glass substrate having light transmittance is prepared. And aluminum (Al) is vapor-deposited through the mask of a predetermined pattern on one main surface of this sealing substrate 200, and the heat conductive layer 250 of a pattern as shown in FIG. 4 is formed.

Subsequently, an ultraviolet curable acrylic resin is further applied to the main surface of the sealing substrate 200 on which the heat conductive layer 250 is formed to a thickness of 5 μm and dried. Then, the acrylic resin is selectively exposed by irradiating the entire other main surface (the surface on which the heat conductive layer 250 is not formed) of the sealing substrate 200 with ultraviolet rays. Then, the spacer 300 is formed by developing the acrylic resin.
Other processes were performed in the same manner as in Example 1 to manufacture an organic EL display device.

  In the organic EL display device 1 thus manufactured, the life test similar to that of Example 1 was performed. As a result, the lifetime in which the luminance of the organic EL element 40 was reduced by half was about 30,000 hours, and sufficient life characteristics were obtained. It was confirmed that it was obtained.

(Example 3)
A method for manufacturing the organic EL display device in Example 3 will be described. Here, the array substrate 100 having the same structure as in the first embodiment is used. As the sealing substrate 200, a 0.7 mm thick glass substrate having light transmittance is prepared. Then, a solder paste is screen-printed to a thickness of 10 μm on one main surface of the sealing substrate 200 through a mask having a predetermined pattern, and then baked to form a spacer 300 having a pattern as shown in FIG. Is fixedly formed on the sealing substrate 200.
Other processes were performed in the same manner as in Example 1 to manufacture an organic EL display device.

  In the organic EL display device 1 manufactured as described above, a life test similar to that of Example 1 was performed. As a result, the lifetime at which the luminance of the organic EL element 40 was reduced by half was about 20,000 hours, and sufficient life characteristics were obtained. It was confirmed that it was obtained.

Example 4
A method of manufacturing the organic EL display device in Example 4 will be described. Here, the array substrate 100 having the same structure as that of the second embodiment is used. As the sealing substrate 200, a 0.7 mm thick glass substrate having light transmittance is prepared. Then, an ultraviolet curable acrylic resin containing carbon particles is applied to one main surface of the sealing substrate 200 to a thickness of 5 μm and dried. Then, the acrylic resin is selectively exposed by irradiating the main surface of the sealing substrate 200 with ultraviolet light through a photomask having a predetermined pattern (pattern capable of transmitting ultraviolet light at a portion where the spacer is formed). Then, the spacer 300 is formed by developing the acrylic resin.
Other processes were performed in the same manner as in Example 1 to manufacture an organic EL display device.

  In the organic EL display device 1 thus manufactured, the life test similar to that of Example 1 was performed. As a result, the lifetime in which the luminance of the organic EL element 40 was reduced by half was about 30,000 hours, and sufficient life characteristics were obtained. It was confirmed that it was obtained.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the spirit of the invention in the stage of implementation. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

FIG. 1 is a diagram schematically showing a configuration of an organic EL display device according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing a partial cross-sectional structure of the organic EL display device according to the first embodiment. FIG. 3 is a perspective view schematically showing a structure of a sealing substrate applicable to the first embodiment. FIG. 4 is a perspective view schematically showing another structure of the sealing substrate applicable to the first embodiment. FIG. 5 is a diagram schematically showing a partial cross-sectional structure of the organic EL display device according to the second embodiment. FIG. 6 is a perspective view schematically showing a structure of a sealing substrate applicable to the second embodiment. FIGS. 7A to 7C are views for schematically explaining a method for manufacturing a sealing substrate applicable to the second embodiment. FIG. 8 is a diagram schematically showing a partial cross-sectional structure of the organic EL display device according to the third embodiment. FIG. 9 is a perspective view schematically showing the structure of a sealing substrate applicable to the third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Organic EL display apparatus, 10 ... Pixel switch, 20 ... Drive transistor, 30 ... Storage capacitor element, 40 ... Organic EL element, 60 ... 1st electrode, 64 ... Organic active layer, 66 ... 2nd electrode, 70 ... Partition , 100 ... Array substrate, 200 ... Sealing substrate, 250 ... Thermally conductive layer, 300 ... Spacer, 400 ... Sealing material, PX ... Pixel

Claims (15)

In a display area for displaying an image, a first electrode formed in an independent island shape for each pixel arranged in a matrix, and a second electrode arranged opposite to the first electrode and formed in common for all pixels An array substrate comprising: an organic active layer held between the first electrode and the second electrode;
A sealing substrate for sealing the array substrate,
The display device, wherein the sealing substrate includes a heat conductive layer having a higher thermal conductivity than the sealing substrate.   The display device according to claim 1, wherein the heat conductive layer has a heat conductivity of 10 W / m · K or more.   The display device according to claim 1, wherein the heat conductive layer is integrally formed on a surface facing the array substrate.   The display device according to claim 1, wherein the heat conductive layer is formed to extend from a sealing region between the array substrate and the sealing substrate to the outside thereof.   The display device according to claim 1, further comprising a spacer for forming a predetermined gap between the array substrate and the sealing substrate. The heat conductive layer has a light shielding property,
The display device according to claim 5, wherein the spacer is formed integrally with a surface of the sealing substrate facing the array substrate together with the heat conductive layer.   The display device according to claim 1, wherein the heat conductive layer is formed of a metal material.   The display device according to claim 1, wherein the heat conductive layer is formed of a resin material containing conductive particles.   The display device according to claim 1, wherein the heat conductive layer is formed of a conductive polymer material. In a display area for displaying an image, a first electrode formed in an independent island shape for each pixel arranged in a matrix, and a second electrode arranged opposite to the first electrode and formed in common for all pixels An array substrate comprising: an organic active layer held between the first electrode and the second electrode;
A sealing substrate for sealing the array substrate;
A spacer disposed between the array substrate and the sealing substrate,
The display device, wherein the spacer has a higher thermal conductivity than the sealing substrate.   The display device according to claim 10, wherein the spacer has a thermal conductivity of 10 W / m · K or more.   The display device according to claim 10, wherein the spacer is integrally formed on a surface of the sealing substrate facing the array substrate.   The display device according to claim 1, wherein the heat conductive layer is formed of a metal material.   The display device according to claim 10, wherein the spacer is formed of a resin material containing conductive particles.   The display device according to claim 10, wherein the spacer is made of a conductive polymer material.

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