JP2002208491A - Self-illuminating display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic self-illuminating display device which can improve light output efficiency to the surface. SOLUTION: For the organic self-illuminating display device in which a plurality of display pixels equipped with a plurality of first electrodes formed in the form of islands, second electrodes arranged in opposition to the first electrodes and an organic thin film layer containing at least an organic illuminating layer and held between the first electrodes and the second electrodes are arranged in the form of a matrix, and any ones of the first and second electrodes are provided as light output surfaces, the forming surface of each electrode on the side arranged in opposed relation to the light output surface through the organic thin film layer between the first and second electrodes is formed at an acute angle to the light output surface in the edge side of the individual display pixel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a self-luminous display device.

[0002]

2. Description of the Related Art Light emitting diodes are used as light modulation layers of pixels,
A display device using a liquid crystal, an organic EL (Electro Luminescence), or the like can reduce the thickness of a display portion. Therefore, the display device is not limited to a display device such as an office machine or a computer, and has a tendency to expand its application range. Among these display devices, organic E
The organic self-luminous display device using L has the advantages described in the following items a to d as compared with an LCD (liquid crystal display device).

A. Since it is a self-luminous type, a clear display and a wide viewing angle can be obtained, and further, since a backlight is not required, low power consumption, light weight, and thinness can be achieved. b. The response speed is fast, for example, milliseconds (mse
In contrast to the order of c), in the case of the organic self-luminous display device, it is of the order of microseconds (μsec). c. Since light is emitted by the solid layer, the operating temperature range may be widened.

[0004] Due to these advantages, their development has been actively pursued. In particular, TFTs using polycrystalline silicon
Research and development of a polycrystalline silicon TFT type organic self-luminous panel having an active matrix structure capable of high-definition display by being combined with a (thin film transistor) have been actively conducted.

FIG. 7 is a schematic sectional view of an array substrate constituting a conventional organic self-luminous display of this type. Anode 1
09 and an organic thin film layer including an organic light emitting layer 113 are held between the cathode 115 and electrons and holes are injected and recombined into the organic light emitting layer 113 to generate excitons,
It emits light using the emission of light when it is deactivated.

As shown in FIG. 7, an organic self-luminous display device has a polycrystalline silicon layer 103, a gate insulating film 104,
A passivation film 110 and a partition insulating film 111 are formed on the anode 109 connected to the driving TFT including the gate electrode 105 and the source / drain electrodes 107.

[0007]

Conventionally, the luminous intensity of an organic self-luminous display device is the luminous intensity of an LCD (100 to 1).
50 nt). In addition, the occurrence of crosstalk between adjacent pixels, particularly, in the case of color display, R, G,
The colors are mixed between the adjacent pixels of the display pixel where each color of B is formed, and the contrast is reduced.

The present invention has been made to solve the above problems, and has as its object to provide a self-luminous display device capable of improving the efficiency of extracting light to a light exit surface. I do. Another object of the present invention is to provide a self-luminous display device in which crosstalk between adjacent pixels is suppressed.

[0009]

According to the first aspect of the present invention,
A plurality of first electrodes formed in an island shape, a second electrode disposed to face the first electrode, and a self-luminous portion held between the first and second electrodes and including at least a light-emitting layer. A plurality of display pixels are arranged in a matrix, and the first and second display pixels are arranged in a matrix.
In a self-luminous display device having one of the electrodes as a light emitting surface, a light reflecting surface that extracts light heading from one display pixel to another adjacent display pixel to the light emitting surface side is the one display pixel and the other. It is characterized by being provided between display pixels.
The invention according to claim 2 is the self-luminous display device according to claim 1, further comprising a partition wall for electrically insulating the first electrodes, and the light emitting layer of the first or second electrode. The formation surface of the electrode on the side disposed opposite to the light exit surface is formed at an acute angle with respect to the light exit surface by the inclination angle of the opening of the partition wall formed at the edge of each display pixel. A light reflecting surface is formed.

According to a third aspect of the present invention, in the self-luminous display device according to the second aspect, the second electrode is formed continuously over a plurality of display pixels.

According to a fourth aspect of the present invention, in the self-luminous display device according to the second aspect, the electrode forming surface on the side opposed to the light emitting surface is provided on the entire periphery of the edge of each display pixel. It is characterized by being formed so as to form an acute angle with respect to the light emitting surface.

According to a fifth aspect of the present invention, in the self-luminous display device according to the second aspect, each of the plurality of first electrodes is electrically insulated by a partition insulating film, and is provided on the entire surface covering the partition insulating film. The second electrode is formed, and the second electrode is formed to form an acute angle with respect to the light emitting surface at the edge of each display pixel due to the inclination angle of the opening formed in the partition insulating film on the edge of the display pixel. It is characterized by being performed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic plan view of an organic self-luminous display device according to a first embodiment of the present invention, and FIG. 2 is a schematic sectional view thereof. The display area of this self-luminous display device is composed of a plurality of display pixels 1 arranged in a matrix as shown in an enlarged view in FIG. 3A, and FIG. 4A is a schematic sectional view of one display pixel, and FIG. 4B is an enlarged sectional view of a characteristic portion thereof.

An organic self-luminous display device is configured by sealing an array substrate on which display pixels are formed and a counter substrate disposed to face the array substrate in a nitrogen atmosphere. In the present embodiment, the display surface is on the array substrate side, and light is extracted outside via the anode.

As shown in FIG. 1, the array substrate has a display area 120 in which display pixels are formed in a matrix, and an X-direction drive circuit 121 and a Y-direction drive circuit 123 arranged on two sides of the substrate. As shown in FIG. 5, each of the display pixels includes a pixel TFT 44 which is a pixel switch that has a source connected to the signal line 41 and a gate connected to the gate line 43 to select a display pixel. Pixel TFT
A display element 46 is provided which has a gate connected to the drain of 44 and a source connected to the current supply line 42 and emits light by a current supplied from a driving TFT 45 which is a driving element.

FIG. 4A is a partial schematic sectional view of each display pixel. The TFT shown here is a driving TFT, and is a partially schematic vertical sectional view of a display pixel portion. In FIG. 4A, an undercoat layer 102 is laminated on a light-transmitting substrate 101, and a polycrystalline silicon layer 103 formed in an island shape on the undercoat layer 102 has a source region 103a, a channel region 103b, Drain region 103
c. The gate insulating film 10 is formed on the entire surface of the undercoat layer 102 including the polycrystalline silicon layer 103.
4 is formed, and a gate electrode 105 is formed at a position corresponding to the channel region 103 b of the polycrystalline silicon layer 103 via a gate insulating film 104. The source electrode and the drain electrode connected to the source region 103a and the drain region 103b of the polycrystalline silicon layer are electrically insulated from the gate electrode by the interlayer insulating film 106. A transparent member, for example, an anode 109 made of ITO (Indium Tin Oxide) is formed in an island shape in a predetermined pixel region on the interlayer insulating film 106, and is electrically connected to a drain electrode.

Then, a passivation film 110 made of an inorganic material having an opening on the anode and a partition insulating film 111 made of an organic material are formed.
Is laminated on the anode, and the cathode 115 is formed continuously across a plurality of pixels in opposition to the anode through the organic thin film layer. The organic thin film layer includes, for example, an anode buffer layer 112, an organic light emitting layer 113, and a cathode buffer layer 114. The anode buffer layer 112 and the cathode buffer layer 114 are each formed of a laminated film of an inorganic material or an organic material.

The partition insulating film 111 is formed as shown in FIGS.
As shown in (a) and (b), an opening is provided between adjacent display pixels. That is, an opening (shaded area) 31 of the partition insulating film 111 is formed over the entire periphery inside the edge of each display pixel, and the opening 31 is formed by connecting the wall surface of the partition insulating film on the anode 109 side to the substrate. For an acute angle (θ <90 °), preferably 4
It is formed to be inclined at 5 degrees or more. Thereby, the light traveling in the horizontal direction, that is, the light components P2 and P3 in FIG. 4 are refracted by the cathode 115 made of a metal film and proceed toward the display surface, so that the emission intensity of the display panel is increased.

Hereinafter, a method for manufacturing the organic self-luminous display device according to this embodiment will be described.

First, a glass substrate 101 is prepared, and a film having a thickness of, for example, 50 nm is formed on one main surface of the glass substrate 101.
An undercoat layer 102 formed by laminating SiNx and SiOx having a thickness of 100 nm is formed. Subsequently, a polycrystalline silicon layer 103 having a thickness of, for example, 50 nm is formed on the undercoat layer 102. An island region of the thin film transistor is formed by patterning.

Next, over the entire surface of the undercoat layer 102 including the polycrystalline silicon layer 103, for example,
A gate insulating film 104 of SiOx having a thickness of 300 nm is formed.
The gate electrode 105 is formed by depositing oW and patterning it.

Next, ion implantation is performed from above the gate insulating film 104 using the gate electrode 105 as a mask, so that a region located below the gate electrode of the polycrystalline silicon layer 103 becomes a channel region, and a source region and a drain region are formed on both sides thereof. Form an area.

Next, over the entire surface of the gate insulating film 104 including the gate electrode 105, for example, a 660 nm-thick Si
An interlayer insulating film 106 made of Ox is formed, followed by ITO
(Indium Tin Oxide) is deposited, and this ITO is patterned to form an island-shaped
An anode 109 is formed as one electrode.

Next, a hole is formed through the interlayer insulating film 106 and the gate insulating film 104 to reach the source region and the drain region. A metal film such as Mo having a thickness of 50 nm and Al having a thickness of 450 nm are formed in the hole. The source / drain electrodes 107 are formed by embedding a 100 nm Mo laminated film. Thereby, the anode 109 is connected to the drain of the driving TFT.

Next, on the interlayer insulating film 106 including the surface of the anode 109, for example, a passivation film 110 made of SiNx having a thickness of 450 nm is formed, and an opening for exposing the surface of the anode 109 is provided. Further, an insulating partition wall insulating film 111 is provided on the exposed surface of the anode 109 and the passivation film 110, and a portion indicated by an arrow M, that is, a first opening for exposing the surface of the anode 109 is provided.
A second opening is formed at the position indicated by the arrow S, that is, inside the edge of the display pixel. The opening of the partition insulating film 111 is provided so as to cover the end of the anode 109, and prevents a short circuit with a cathode described later. In addition, as shown in FIG. 4B, the opening of the portion indicated by the arrow S is such that the wall surface 111F of the partition insulating film 111 on the anode 109 side is inclined at an acute angle to the substrate, for example, at θ = 45 °. Let me.

Next, the partition insulating film 1 including the surface of the anode 109
An anode buffer layer 112 formed by stacking a hole transport layer, a hole injection layer, and the like to a thickness of 110 nm is deposited on the substrate 11, an organic light emitting layer 113 having a thickness of 30 nm is stacked, and an electron injection layer, etc. After depositing a cathode buffer layer 114 having a thickness of 30 nm, a cathode 115 is formed on the entire surface.

As a result, of the light components P 1, P 2, and P 3 radiated from the organic light emitting layer 113, the light component P 1 goes directly to the display surface, and the light components P 2 and P 3 go laterally through the partition insulating film 111. Then, the light is refracted in the display surface direction by the cathode 115 on the wall surface on the anode 109 side of the opening of the partition insulating film 111 indicated by the arrow S, thereby increasing the light emission intensity of the display panel.

Incidentally, the wiring 108 may be arranged between the display pixels as shown in FIG.
It is desirable to provide an inclined surface for refracting the light components P2 and P3 inside the portion 8.

Further, in the present embodiment, the inclined surface for refracting the light components P2 and P3 is set at 45 degrees with respect to the substrate surface. can get.

By the way, in the above embodiment, FIG.
Alternatively, focusing on the portion indicated by the arrow S in FIG. 4B, the light component P3 passes through the partition insulating film 111, is reflected by the cathode 115 via the anode buffer layer 112, and travels toward the display surface. According to this configuration, the light component P3 is attenuated in accordance with the absorption coefficient (extinction coefficient) of the anode buffer layer 112 and proceeds in the direction of the display surface, so that the efficiency decreases from the viewpoint of increasing the emission intensity of the display panel. In order to prevent this, the inclined wall surface 11 of the opening of the partition insulating film 111 indicated by the arrow S
If the cathode 115 is directly applied to the first floor, it is possible to prevent the anode buffer layer 112 from attenuating the light component P3 twice.

FIG. 6 is a vertical sectional view of a display pixel of a second embodiment of the organic self-luminous display device according to the present invention, which is made by paying attention to this point. 6, the same elements as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. This is because, similarly to the first embodiment, when an opening is formed in the partition insulating film 111, the wall surface 111 on the side of the anode 109 is also formed at the position indicated by the arrow S.
A second opening is formed such that F forms an angle of about 45 degrees, for example. In the display pixel 11A shown here, the anode buffer layer 112, the organic light emitting layer 113, and the cathode buffer layer 114 are formed in the above-described first opening, that is, in a region surrounded by the partition insulating film on the anode 109. Cathode 1 over the entire surface
15 are formed. Accordingly, the cathode 115 is directly attached to the wall surface 111F of the partition insulating film 111 which is inclined at approximately 45 degrees at the position indicated by the arrow S.

With this configuration, the light component P3 (and P2) traveling laterally from the organic light emitting layer 113 is directly reflected by the cathode 115 on the inclined surface of the partition insulating film 111. The light is not attenuated by the layer 112, and the light emission intensity of the display panel can be increased as compared with the embodiment shown in FIG.

As described above, an opening is provided between adjacent display pixels of the partition insulating film of the organic self-luminous display device, and the wall surface of the opening of the partition insulating film is formed to be at an acute angle with respect to the light emitting surface. Therefore, it is possible to efficiently extract the light leaked in the direction parallel to the light emitting surface in the display pixel.

That is, the electrode on the side facing the light emitting surface via the organic light emitting layer is formed of a member having high reflectance, and this electrode forms an acute angle with the light emitting surface at the end of each display pixel. Since it is formed, light emitted from the organic light emitting layer can be efficiently extracted to the light emitting surface side.

If this opening is formed over the entire inner surface of the edge of each display pixel, it is possible to prevent light leakage between adjacent pixels, suppress crosstalk, improve contrast, and In the case of color display, color mixing between adjacent pixels can be prevented.

FIG. 1 shown in order to grasp the overall configuration,
The pixel 1 is formed by arranging three display pixels shown in FIG. 4 or FIG. 6 side by side, and a plurality of these pixels 1 are arranged in a matrix to form a display region 120 of the organic self-luminous panel array 100. It is a top view. In this case, the display area 120
On the other hand, the glass substrate 101 is formed to have a large size in both the vertical and horizontal directions, and particularly protrudes to the right and lower sides of the drawing, of which the X-direction drive circuit 121 is mounted on the right side and is derived from each pixel. Connected to the wiring 122, the Y-direction drive circuit 123 is mounted on the lower side,
It is connected to a wiring 124 derived from each pixel.

FIG. 2 is a longitudinal sectional view of an organic self-luminous panel assembled using the organic self-luminous panel array 100 shown in FIG. 1 as a constituent element. Direction drive circuit 12
A sealing member 131 is provided at the edge of the Y-direction drive circuit 123 so as to surround the Y-direction drive circuit 123. On the sealing member 131, on its inner surface, for example, zeolite or BaO
A glass substrate 133 coated with a desiccant 132 such as is mounted, and the inside is further filled with dry nitrogen. As a result, the organic self-luminous panel 2 whose display surface is at the bottom of the drawing
00 is configured. And this organic self-luminous panel 2
00 makes it possible to configure an organic self-luminous display device.

The organic light-emitting layer in the first and second embodiments are constituted by vapor deposition or the like using an organic luminescent material of low molecular weight, such as Alq _3, for example.

Next, a third embodiment will be described. FIG. 9 is a schematic sectional view of an array substrate of an organic self-luminous display according to a third embodiment of the present invention. In the present embodiment, the organic light emitting layer 113 is formed corresponding to R, G, and B by an ink-jet method using a polymer organic light emitting material such as polyfluorene. That is, the polymer organic light emitting material is sequentially discharged, and the anode 10 serving as the first electrode is discharged.
9 at a position corresponding to the opening of the partition insulating film 111.
Organic light-emitting layer 113 via 0 nm anode buffer layer 112
Are selectively formed. In the present embodiment, the organic light emitting layer 113 is formed to a thickness of, for example, 80 nm. By forming the organic light emitting layer 113 using a high molecular weight organic light emitting material in this manner, it is possible to easily cope with a design change of the substrate size of the array substrate. Further, since the light emitting material can be selectively discharged only to a necessary portion, the material use efficiency is improved.

Next, a fourth embodiment will be described. FIG. 9 is a schematic sectional view of an array substrate of an organic self-luminous display according to a fourth embodiment of the present invention. In the present embodiment, the first electrode connected to the driving TFT (driving element) 45, here, the anode 109 is connected to the driving TFT 45 via the insulating film 116.
Connected to the drain electrode 107b. Since the first electrode is disposed on the signal line 41 and the TFTs 44 and 45 with the insulating film 116 interposed therebetween, the signal line 41 and the first electrode are disposed on the same plane as in the first to third embodiments. As compared with the case where the first electrode is provided, the degree of freedom of the arrangement position of the first electrode can be improved, and the light emitting area can be increased.

Further, each display pixel 1 is not limited to the above-described structure. For example, as shown in FIG. 10, a Y-direction driving circuit 123 is provided based on a scanning signal supplied from an X-direction driving circuit 121.
A pixel switch 44 for selecting a display pixel to which a video signal supplied from a pixel is written, a first capacitor 47 for holding the video signal written from the signal line 41 via the pixel switch 44 for one horizontal scanning period, And a reset circuit 48 for supplying a driving current based on the driving current to the display element 46.

Here, the pixel switch 44 is, for example, an n-type TFT.
, And the driving element 45 is formed of a p-type TFT. Further, the reset circuit 48 includes a second capacitor 4 disposed between the drain of the pixel switch and the gate of the driving element.
8a, a first switch 48b disposed between the gate and the drain of the driving element 45, and a second switch 48c disposed between the drain of the driving element 45 and the first electrode of the display element 46.

Here, the display element refers to a laminated body composed of a first electrode, a second electrode disposed to face the first electrode, and a self-luminous portion held between the first electrode and the second electrode. .
The self-light emitting portion (organic thin film layer) may be composed of a three-layer stack of an anode buffer layer, a cathode buffer layer, and a light emitting layer formed for each color, which are formed in common for each color. It may be composed of two layers or a single layer.

In the above-described embodiment, the anode is disposed on the light emitting surface side as a transparent electrode, and the cathode is disposed on the non-light emitting surface as a light reflecting electrode. However, the cathode is formed of a light-transmitting conductive film. Then, the anode may be disposed on the non-light-emitting surface side by forming the anode into a laminated structure of a conductive film and a metal layer on the light-emitting surface side.

In the above-described embodiment, the self-luminous display device of the type in which light is extracted to the outside through an array substrate on which a TFT or the like is arranged has been described. May be one that extracts light to the outside through the second electrode, and in any case, a light emission surface that extracts light heading from one display pixel to another adjacent display pixel to the light emission surface side. It is important to provide between one display pixel and another display pixel. Further, in the above-described embodiment, the case where the opening of the partition insulating film is formed over the entire circumference of each display pixel has been described. However, the present invention is not limited to this. Is also good. In particular, in the case of color display, color mixture between adjacent pixels can be suppressed if the R, G, and B colors are formed in stripes.

The self-luminous display has been described by taking an electroluminescent display among organic self-luminous devices as an example, but is not limited to this.

[0047]

As is apparent from the above description, according to the present invention, it is possible to provide a self-luminous display device capable of improving the efficiency of extracting light to the light emitting surface. Further, according to the present invention, it is possible to provide a self-luminous display device in which crosstalk between adjacent pixels is suppressed.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an organic self-luminous panel array of an organic self-luminous display device according to the present invention.

FIG. 2 is a longitudinal sectional view showing the configuration of the organic self-luminous panel array shown in FIG.

FIG. 3 is a plan view of one pixel of a general organic self-luminous display device and a plan view of a display pixel for explaining an outline of the present invention.

FIG. 4 is a vertical cross-sectional view showing a configuration of a display pixel and a vertical cross-sectional view showing a detailed configuration of a characteristic portion thereof, for explaining a first embodiment of an organic self-luminous display device according to the present invention.

FIG. 5 is a circuit diagram in which components of a panel array of the organic self-luminous display device according to the present invention are arranged in a plane.

FIG. 6 is a longitudinal sectional view showing a configuration of a display pixel for explaining a second embodiment of the organic self-luminous display device according to the present invention.

FIG. 7 is a longitudinal sectional view of a display pixel for explaining a configuration of a conventional organic self-luminous display device.

FIG. 8 is a vertical sectional view of a display pixel for explaining a third embodiment of the organic self-luminous display device according to the present invention.

FIG. 9 is a longitudinal sectional view of a display pixel for explaining a fourth embodiment of the organic self-luminous display device according to the present invention.

FIG. 10 is a circuit diagram in which components of a panel array of an organic self-luminous display device according to the present invention are arranged in a plane.

[Explanation of symbols]

 1 pixel 11, 11A, 12, 13 display pixel 21 anode 31 opening 100 organic self-luminous panel array 101 glass substrate 102 undercoat layer 103 polycrystalline silicon layer 104 gate insulating film 106 interlayer insulating film 107 source / drain electrode 108 wiring 109 anode Reference Signs List 110 passivation film 111 partition insulating film 111F wall surface 112 anode buffer layer 113 organic light emitting layer 114 cathode buffer layer 115 cathode 121 X-direction drive circuit 123 Y-direction drive circuit 131 sealing member 133 glass substrate 200 organic self-luminous panel

Claims (5)

[Claims] A plurality of first electrodes formed in an island shape; a second electrode disposed to face the first electrode;
A plurality of display pixels held between two electrodes and including a self-light-emitting portion including at least a light-emitting layer are arranged in a matrix, and one of the first and second electrodes is arranged in a light-emitting surface. In the light-emitting display device, a light reflecting surface for extracting light from one display pixel to another adjacent display pixel to the light emission surface side is provided between the one display pixel and the other display pixel. Light-emitting display device. 2. The self-luminous display device further comprises a partition wall for electrically insulating the first electrode, and the light emitting surface of the first or second electrode via the light emitting layer. The formation surface of the electrode on the side arranged oppositely forms the light reflection surface that forms an acute angle with respect to the light emission surface due to the inclination angle of the opening of the partition wall formed on the edge of each of the display pixels. The self-luminous display device according to claim 1, wherein: 3. The self-luminous display device according to claim 2, wherein said second electrode is formed continuously over a plurality of said display pixels. 4. The method according to claim 1, wherein a surface of the electrode on a side opposed to the light emitting surface is formed so as to form an acute angle with respect to the light emitting surface over the entire periphery of each of the display pixels. 3. The self-luminous display device according to claim 2, wherein: 5. The plurality of first electrodes are each electrically insulated by a partition, and the second electrode is formed on the entire surface covering the partition, and is formed on the partition on an edge of the display pixel. 3. The self-luminous display device according to claim 2, wherein the second electrode is formed at an edge of each of the display pixels so as to form an acute angle with respect to the light emitting surface due to an inclination angle of the opening. .