JP5137685B2 - Display device - Google Patents

Description

  The present invention relates to a self-luminous display device, and more particularly to an electroluminescent display device in which a light emitting substrate having a light emitting portion including an electroluminescent layer and an active matrix substrate having a driving circuit such as a TFT are bonded together.

  In OA equipment, AV equipment, portable terminal equipment, and the like, electroluminescent display devices are used as display devices capable of high-quality display, thinning, and low power consumption. One of the electroluminescent display devices is an organic electroluminescence (EL) display device using an organic electroluminescent layer. In this organic EL display device, a technique for displaying an image by driving a plurality of organic EL elements arranged in an XY matrix by simple matrix driving (passive driving) is known. Since this simple matrix drive has a limit in the number of scanning lines when performing line sequential drive, active matrix drive with more excellent drive capability has been proposed. This active matrix driving type organic EL display device includes an active matrix substrate, and the active matrix substrate includes a light-transmitting base substrate. On the base substrate, at least one thin film transistor (TFT) made of a-Si, polysilicon or the like is provided for each pixel. Further, a plurality of scanning electrode lines and a plurality of signal electrode lines for selecting and turning on the TFT are further provided on the base substrate, and an organic EL layer is formed on the TFT (for example, , See Patent Document 1).

Next, a conventional improved self-luminous display device will be described.
In the structure of a self-luminous display device, the display device includes an active matrix substrate and a counter substrate disposed to face the active matrix substrate, the active matrix substrate including a first base substrate, A plurality of first pixel electrodes provided on the first base substrate, wherein the counter substrate is on the first pixel electrode side with respect to the second base substrate and the second base substrate. The formed electrode layer, the electro-optic medium formed on the first pixel electrode side with respect to the electrode layer, and the electro-optic medium so as to face each of the plurality of first pixel electrodes. A plurality of second pixel electrodes, and further comprising conductive connection means for electrically connecting the first pixel electrodes of the active matrix substrate and the second pixel electrodes of the counter substrate, respectively. Structure It has been proposed (e.g., see Patent Document 2.).

JP-A-10-189252 JP 2003-66859 A

  However, the conventional configuration sufficiently eliminates mutual influences between the circuits to be bonded, such as electrical interference between the self-light-emitting unit and the drive circuit unit, and the influence of the heat generation of the self-light-emitting unit on the drive circuit. I couldn't. For this reason, it is necessary to adjust the brightness of each manufactured panel, and a buffer circuit is required to ensure image quality.Additional circuit blocks are added to increase the cost and increase the power consumption. Had the problem of inviting.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a display device capable of preventing stable electrical image quality by preventing electrical interference from a driving circuit to a light emitting unit and preventing heat from the light emitting unit from flowing locally to the driving circuit. Is to provide.

A display device according to the present invention includes a drive circuit board having a drive circuit,
A light-emitting substrate disposed to face the drive circuit substrate and having a light-emitting portion;
A ground electrode provided on a bonding surface of the drive circuit substrate and the light emitting substrate, having a ground potential, and extending in an in-plane direction of the bonding surface;
With
The drive circuit of the drive circuit board and the light emitting part of the light emitting board are electrically connected via a connection part electrically insulated from the ground electrode.

The drive circuit board is
A first base substrate;
A drive circuit provided on the first base substrate;
A connection electrode provided on the drive circuit for electrically connecting the drive circuit and a light emitting portion of the light emitting substrate;
May be provided.

Further, the light emitting substrate is
A second base substrate;
A light emitting unit configured by laminating a common electrode, a light emitting layer, and a pixel electrode in this order on the second base substrate;
An intermediate electrode provided on the light-emitting portion and connecting the pixel electrode and the connection electrode of the drive circuit board;
May be provided.

  In the above case, the connection electrode of the drive circuit board and the intermediate electrode of the light emitting board are electrically connected.

  The common electrode may be electrically connected to the ground electrode. In this case, the common electrode has a ground potential.

  Furthermore, the drive circuit substrate and the light emitting substrate may be bonded together via an insulating adhesive layer. In this case, the ground electrode may be provided on the adhesive layer on the driving circuit board side of the bonding surface.

  The adhesive layer may be configured by dispersing insulators.

  Furthermore, the ground electrode may have a planar shape extending over the bonding surface. Alternatively, the ground electrode may have a mesh shape over the bonding surface. Furthermore, the ground electrode may have a plurality of lines arranged in parallel to each other in one direction of the bonding surface.

  As described above, according to the display device according to the present invention, the bonding surface between the drive circuit substrate and the light emitting substrate has a ground potential and develops in the in-plane direction of the bonding surface, for example, a planar ground. An electrode is provided. By this planar ground electrode, electromagnetic waves from the drive circuit are blocked by the ground electrode having the ground potential, and erroneous light emission due to crosstalk in the light emitting portion can be prevented. Furthermore, due to the heat transfer characteristics of the conductor, the heat generated in the self-luminous part is conducted through the ground electrode and diffused in a flat shape, so that heat generation in the low luminance part and heat generation in the high part are made uniform. It is possible to suppress a decrease in efficiency of the light emitting part due to temperature. For this reason, it is possible to minimize the current flowing through the light emitting unit in order to compensate for the decrease in efficiency, and the energy saving effect of the display device can be expected.

  In addition, according to the present invention, since the electrical operation check can be performed between the ground electrode on the surface and the connection electrode connected to the light emitting unit even when inspecting the single drive circuit, the screen around the panel The area of the portion that does not contribute to display can be reduced.

  Hereinafter, display devices according to embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, substantially the same members are denoted by the same reference numerals.

(Embodiment 1)
<Display device>
FIG. 1 is a schematic cross-sectional view showing the overall configuration of the display device 10 according to the first embodiment. The display device 10 includes a drive circuit board 20 having a drive circuit 22 and a light emitting board 30 that is disposed to face the drive circuit board 20 and has a light emitting unit. Further, the drive circuit board 20 and the light emitting board 30 are bonded to each other with an insulating adhesive layer 12, and the bonded surface of the drive circuit board 20 and the light emitting substrate 30 is developed in an in-plane direction, for example, a planar ground. An electrode 14 is provided.

<Drive circuit board>
FIG. 2 is a cross-sectional view of the display device 10 as viewed from the direction perpendicular to the surface of the drive circuit board 20. The drive circuit substrate 20 includes a first base substrate 21, a drive circuit 22 provided on the first base substrate 21, and connection electrodes for electrically connecting the drive circuit 21 and the light emitting portion of the light emitting substrate 30. 23, a signal connection part 26 provided on the connection electrode 23 and in contact with the light emitting part of the light emitting substrate 30, and an insulating layer 24 covering the upper surface of the drive circuit 22.

<Light emitting substrate>
FIG. 3 is a cross-sectional view of the light emitting substrate 30 of the display device 10 that is turned upside down and viewed from a direction perpendicular to the surface. The light emitting substrate 30 has a second base substrate 31 having translucency. A light emitting unit is provided on the second base substrate 31. The light emitting unit includes a planar common electrode 33 formed on the second base substrate 31, a light emitting layer 32 formed on the common electrode 33, and a pixel electrode 34 provided for each RGB color of each pixel. , Is composed of. The light emitting layers 32 are arranged independently so that three colors of R, G, and B can emit light. A pixel electrode 34 is independently formed on the light emitting layer 32 to emit light of three colors R, G, and B, and the pixel electrode 34 is connected to the intermediate electrode 36 through the insulating layer 35. 36 is electrically connected to the connection electrode 23 and formed to emit light.

<Ground electrode>
On the drive circuit board 20 side of the bonding surface of the drive circuit board 20 and the light emitting board 30, a ground electrode 14 that extends in the in-plane direction is provided. Examples of the shape of the ground electrode 14 include a planar shape, a mesh shape, and a plurality of line shapes extending in parallel in one direction. Moreover, it is preferable that the ground electrode 14 has conductivity and good thermal conductivity. As the ground electrode 14, for example, a metal such as gold, silver, copper, or aluminum can be used.

  By providing the ground electrode 14 extending in the in-plane direction on the bonding surface, the electromagnetic wave from the drive circuit 22 is blocked by the ground electrode 14, and erroneous light emission due to crosstalk in the light emitting portion on the light emitting substrate 30 side is prevented. It becomes possible. Furthermore, due to the heat transfer characteristics of the conductor, the heat generated in the light-emitting portion is conducted through the ground electrode 14 and diffused in a planar shape, and the heat generation in the low luminance portion and the heat generation in the high portion are made uniform, and the temperature It is possible to suppress a decrease in the efficiency of the light emitting part due to.

  Further, the connection electrode 23 of the drive circuit board 20 and the intermediate electrode 36 of the light emitting board 30 are electrically connected. As shown in FIGS. 1 and 4A, the connection electrode 23 is electrically insulated from the ground electrode 14 in the same plane as the ground electrode 14, and the drive circuit 22 and the light emitting unit are connected to the ground. The electrodes 14 are electrically connected to each other via connection portions (connection electrode 23 and intermediate electrode 36) that are electrically insulated from the electrode 14.

<Method for manufacturing drive circuit board>
The drive circuit substrate 20 shown in FIG. 2 can be formed by a process similar to the process of forming a substrate using TFTs formed in the process of manufacturing a liquid crystal display device. When forming this drive circuit board | substrate 20, it is based on the following processes, for example.
(A) First, the first base substrate 21 is prepared.
(B) Next, the drive circuit 22 is formed on the first base substrate 21 by a known method.
(C) Next, an insulating layer 24 is formed on almost the entire surface of the first base substrate 21 so as to cover the drive circuit 22 formed on the first base substrate 21.
(D) Finally, a plurality of connection electrodes 23 electrically connected to the drive circuit and a ground electrode 14 insulated from the connection electrodes 23 are formed in the same plane on the insulating layer 24. (FIG. 4A).
Thus, the drive circuit board 20 is formed.

  The connection electrode 23 can use various metals or conductive oxides, and can be patterned by a normal photolithography technique. In the display device 10 according to the first embodiment, the light emitting layer 32 is formed on the light emitting substrate 30 and is not formed on the drive circuit substrate 20, so that the surface of the drive circuit substrate 20 is conventionally provided. Need not be flattened.

<Manufacturing method of light emitting substrate>
A method for manufacturing the light emitting substrate 30 will be described below.
a) First, a second base substrate 31 having translucency is prepared. As the second base substrate 31 having translucency, a transparent substrate such as a glass substrate, a quartz substrate, or a plastic substrate can be used. In addition, since the light emitting substrate 30 and the driving circuit substrate 20 are bonded to each other in a later process, the first base substrate 21 of the driving circuit substrate 20 and the second base substrate 31 of the light emitting substrate 30 use the same material. It is effective. In addition, when the materials of the first base substrate 21 and the second base substrate 31 are different, it is preferable to select and use a material having at least a thermal expansion coefficient in order to suppress the warpage of both the bonded substrates. .

b) Next, a transparent common electrode 33, a light emitting layer 32, and a pixel electrode 34 are sequentially formed on the second base substrate 31. Since the second base substrate 31 and the common electrode 33 are formed of a transparent material, display light emitted from the light emitting layer 32 is extracted to the outside on the second base substrate 31 side.
As a method for forming the light emitting layer 32 on the common electrode 33, when a polymer organic EL material is used, various coating methods such as spin coating, a transfer method, a screen printing method, an ink jet method and the like are used. The In the case of using a low molecular organic EL material, a vapor deposition method or the like is mainly used. Further, in order to perform RGB color display for each pixel, it is necessary to create a light emitting layer containing a light emitting material corresponding to each color of RGB for each pixel of each color. In this case, the same effect can be obtained even if a color filter is provided at the interface between the second base substrate 31 and the common electrode 33.

c) Next, after an insulating layer 35 is formed on the pixel electrode 34, a part of the pixel electrode 34 is exposed.
d) Finally, an intermediate electrode 36 electrically connected to the pixel electrode 34 is provided on the patterned insulating layer 35.
Thus, the light emitting substrate 30 is obtained.

<Manufacturing method of display device>
The display device 10 shown in FIG. 1 can be obtained by bonding the drive circuit substrate 20 formed by the above method and the light emitting substrate 30 with the adhesive layer 12 made of an insulating adhesive. FIGS. 4A and 4B are plan views on each side of a connecting portion that electrically connects the drive circuit board 20 and the light emitting board 30. FIG. 4A is a schematic cross-sectional view showing the configuration of the connecting portion on the drive circuit board 20 side. FIG. 4B is a schematic cross-sectional view illustrating the configuration of the connection portion on the light emitting substrate 30 side. Also, the squares shown in FIGS. 4A and 4B indicate the pixel 41, and this pixel 41 is further divided into R, G, and B light emitting portions (41R, 41G, and 41B). Thus, the function of the display device 10 can be realized.
a) First, the connecting portion (connecting electrode 23) on the drive circuit board 20 side and the connecting portion (intermediate electrode 36) on the light emitting substrate 30 side are arranged so as to face each other, and the insulating adhesive layer 12 is interposed therebetween. to paste together. In this case, the connection electrode 23 of the drive circuit board 20 and the intermediate electrode 36 of the light emitting board 30 are electrically connected through a contact hole provided in the ground electrode 14. Note that the signal connection portion 26 at the tip of the connection electrode 23 is made higher than the surface of the ground electrode 14 as shown in FIG. In addition, the display device 10 can be configured.
Further, as shown in FIG. 4A, the connection electrodes 23R, 23G, and 23B on the drive circuit board 20 side are arranged obliquely for each color of RGB, so that the intermediate electrode 36R for each color of RGB on the light emitting board 30 side. , 36G, and 36B can be formed in a rectangular shape (FIG. 4B). As a result, it is possible to provide a margin for the bonding accuracy between the drive circuit board 20 and the light emitting board 30.

  In this case, the adhesive layer 12 is desirably insulative. For example, if a conductive filler is included in order to give conductivity to the adhesive layer 12, the risk of short-circuiting increases when the conductive filler is present in the adhesive layer 12 between the ground electrode 14 and the connection electrode 23. To do. Therefore, the adhesive layer 12 is desirably insulative. In addition, by including an insulator having high thermal conductivity such as titanium oxide in the adhesive layer 12, the heat generated in the light emitting substrate 30 can be easily transferred to the ground electrode 14 on the bonding surface with the drive circuit substrate 20. And soaking can be promoted. In the case where a thermally conductive insulator is dispersed in the adhesive layer 12, the size of the insulator is such that the size of the connection electrode 23 and the ground electrode 14 is reduced in order to suppress an open defect between the drive circuit substrate 20 and the light emitting substrate 30. It is necessary to make the particle diameter less than the difference in height.

  As described above, according to the first embodiment, the planar ground electrode 14 having the ground potential is formed on the bonding surface of the drive circuit substrate 20 and the light emitting substrate 30 to thereby heat the light emitting substrate 30. It becomes possible to disperse the display device 10 as a whole. Further, the planar ground electrode 14 shields an electric signal from the drive circuit board 20 and suppresses interference with the light emitting portion of the light emitting board 30. On the other hand, the heat generated from the light emitting substrate 30 is diffused throughout the drive circuit substrate 20 through the planar ground electrode 14, so that the heat energy is diffused throughout the display device 10, and the light emitting portion of the light emitting substrate 30 emits light. It is possible to ensure efficiency. As a result, it is possible to obtain a display device in which the heat deactivation of the light emitting portion and the variation in drive current due to heat in the drive circuit are suppressed.

  Also, as shown in FIGS. 4A and 4B of the present embodiment, the connection electrode 23 of the drive circuit board 20 and the intermediate electrode 36 of the light emitting board 30 are formed, so that the drive circuit board 20 and A margin can be given to the alignment accuracy with the light emitting substrate 30. Thereby, the yield in the bonding process of the drive circuit board 20 and the light emitting board 30 can be improved.

  As described above, in the display device of the present invention, the ground electrode has a ground potential on the bonding surface of the driving circuit substrate and the light emitting substrate and is developed in the in-plane direction of the bonding surface. As a result, electromagnetic waves from the drive circuit are blocked by the ground electrode having the ground potential, and erroneous light emission due to crosstalk can be prevented. Furthermore, from the heat transfer characteristics of the conductor, the heat generated in the self-light-emitting portion is conducted through the ground electrode and diffused in a planar shape, so that heat generation in the low luminance portion and heat generation in the high portion are made uniform, It is possible to suppress a decrease in efficiency of the self-luminous part due to temperature. For this reason, it is possible to minimize the current flowing through the self-light-emitting portion in order to compensate for the decrease in efficiency, and it is possible to expect the energy saving effect of the display device.

It is a schematic sectional drawing which shows the whole structure of the display apparatus which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the structure of the drive circuit board | substrate of the display apparatus which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the structure which turned upside down the light emitting substrate of the display apparatus which concerns on Embodiment 1 of this invention. (A) is a top view which shows the structure of the connection part by the side of the drive circuit board in Embodiment 1 of this invention, (b) is a top view which shows the structure of the connection part by the side of a light emission board | substrate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Display apparatus 12 Adhesive layer 14 Ground electrode 20 Drive circuit board 21 1st base board 22 Drive circuit 23, 23R, 23G, 23B Connection electrode 24 Insulation layer 26 Signal connection part 30 Light emission board 31 Second base board 32 Light emission layer 33 Common Electrode 34 Pixel electrode 35 Insulating layer 36, 36R, 36G, 36B Intermediate electrode 41, 41R, 41G, 41B Pixel

Claims (7)

A drive circuit board having a drive circuit;
A light-emitting substrate disposed to face the drive circuit substrate and having a light-emitting portion;
A ground electrode provided on a bonding surface of the drive circuit substrate and the light emitting substrate, having a ground potential, and extending in an in-plane direction of the bonding surface;
With
The drive circuit of the drive circuit board and the light emitting part of the light emitting board are electrically connected via a connection part electrically insulated from the ground electrode ,
The drive circuit substrate and the light emitting substrate are bonded together via an insulating adhesive layer,
The display device , wherein the ground electrode is provided immediately below the adhesive layer on the drive circuit board side of the bonding surface . The drive circuit board is
A first base substrate;
A drive circuit provided on the first base substrate;
A connection electrode provided on the drive circuit for electrically connecting the drive circuit and a light emitting portion of the light emitting substrate;
With
The light emitting substrate is
A second base substrate;
A light emitting unit configured by laminating a common electrode, a light emitting layer, and a pixel electrode in this order on the second base substrate;
An intermediate electrode provided on the light-emitting portion and connecting the pixel electrode and the connection electrode of the drive circuit board;
With
The display device according to claim 1, wherein the connection electrode of the drive circuit substrate and the intermediate electrode of the light emitting substrate are electrically connected.   The display device according to claim 2, wherein the common electrode is electrically connected to the ground electrode and has a ground potential. The display device according to claim 1 , wherein the adhesive layer is configured by dispersing insulators.   The display device according to claim 1, wherein the ground electrode has a planar shape extending over the bonding surface.   The display device according to claim 1, wherein the ground electrode has a mesh shape extending over the bonding surface.   The display device according to claim 1, wherein the ground electrode has a plurality of line shapes arranged in parallel to each other in one direction of the bonding surface.

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