JP2010186582A - Organic el display - Google Patents

Abstract

The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a high-definition full-color organic EL display device.
A plurality of sub-pixels are provided on the substrate, and the sub-pixels include at least two types of different emission colors. The sub-pixels include a lower electrode, an organic compound layer, and an organic compound layer. In the organic EL display device including the upper electrode 13, the sub-pixel is adjacent to the sub-pixel having the same emission color in at least one direction, and an insulating layer 14 is provided between the sub-pixels having different emission colors. Organic EL display device 1.
[Selection] Figure 1

Description

  The present invention relates to an organic EL display device.

  An organic EL element using electroluminescence (EL) of an organic material is a light emitting element having an organic compound layer such as an organic carrier transport layer or an organic light emitting layer between an anode and a cathode. Organic EL elements are attracting attention as light-emitting elements that can emit light with high luminance by low-voltage direct current drive.

  As a specific example of an organic EL display device using such an organic EL element as a display element, there is an active matrix display device in which a thin film transistor (TFT) for driving the organic EL element is provided for each pixel. Here, active matrix display devices are being developed especially from the viewpoint of high image quality and long life.

  By the way, in an organic EL display device, in particular, an organic EL display device for full color display, a plurality of pixels each including a red (R) subpixel, a green (G) subpixel, and a blue (B) subpixel that emit light independently are arranged. That is, the three-color independent light-emitting method is common.

  Here, as a method for manufacturing an organic EL display device for full-color display, a method in which a shadow mask is provided on a substrate and an organic compound layer corresponding to each subpixel is formed by vapor deposition is widely used.

  On the other hand, when the three-color independent light-emitting organic EL display device is employed in a small monitor such as a mobile phone or a camera, the display device itself is required to have high definition. However, when increasing the definition of the organic EL display device, the pitch of the shadow mask openings becomes narrower, making it difficult to manufacture a shadow mask and a higher definition organic EL display device for achieving higher definition. I was doing.

  Therefore, as disclosed in Patent Document 1, a technique has been proposed in which the order of each sub-pixel is inverted for each pixel, for example, R, G, B, B, G, R,. Yes. With this subpixel configuration, for example, R and B become two continuous subpixels. Therefore, since the shadow mask used when forming the R subpixel and the B subpixel only needs to prepare a shadow mask having openings corresponding to two subpixels, it improves the manufacturability of the organic EL display device. I am letting.

  However, between the sub-pixels having different emission colors, the edge of each sub-pixel, for example, the end of each sub-pixel at the boundary between the R sub-pixel and the G sub-pixel, is formed due to the effect of the shadow mask alignment accuracy. The film thickness of the organic compound layer to be formed may become thin or may not be formed. In this case, there is a problem that a short circuit easily occurs between the upper electrode and the lower electrode.

  As a method for solving this problem, Patent Document 1 discloses a method of repairing an open breakdown of a short-circuit portion between an upper electrode and a lower electrode by applying a reverse bias voltage to a sub-pixel.

JP 2004-207126 A

  By the way, between sub-pixels with different emission colors, color mixing occurs due to the deposition of organic compound layers of other colors at the end of each sub-pixel. In addition, the problem of color mixing cannot be solved by the technique of Patent Document 1.

  In order to prevent this color mixture, conventionally, it is necessary to increase the distance between the end portions of the sub-pixels between the sub-pixels having different emission colors. As a result, the aperture ratio of the sub-pixels is reduced. It was. Thus, when the aperture ratio of the sub-pixel is decreased, the voltage for obtaining a certain luminance is increased, so that the power consumption is increased and the lifetime is shortened.

  An object of the present invention is to solve the above-described problems of the prior art, and an object thereof is to provide a high-definition full-color organic EL display device.

The organic EL display device of the present invention includes a substrate,
A plurality of pixels provided on the substrate, and at least two kinds of sub-pixels having different emission colors; and
In the organic EL display device in which the subpixel includes a lower electrode, an organic compound layer, and an upper electrode,
The subpixel is adjacent to a subpixel of the same emission color in at least one direction;
An insulating layer is provided between sub-pixels having different emission colors.

  According to the present invention, a high-definition full-color organic EL display device can be provided.

It is a schematic diagram which shows 1st embodiment in the organic electroluminescence display of this invention, (a) is a plane schematic diagram, (b) is a cross-sectional schematic diagram between A-A 'of (a). It is the schematic of the shadow mask used in the Example. It is a plane schematic diagram which shows 2nd embodiment in the organic electroluminescence display of this invention. It is a plane schematic diagram which shows 3rd embodiment in the organic electroluminescence display of this invention.

  The organic EL display device of the present invention is composed of a substrate and a plurality of pixels formed on the substrate and composed of at least two types of sub-pixels having different emission colors. In the organic EL display device of the present invention, the subpixel includes a lower electrode, an organic compound layer, and an upper electrode.

  Hereinafter, the organic EL display device of the present invention will be described with reference to the drawings. In the following description, a well-known technique or a well-known technique in the technical field of the organic EL display device can be applied to a portion that is not particularly illustrated or described. The embodiment described below is only one form of the present invention, and the present invention is not limited to these.

  1A and 1B are schematic views showing a first embodiment of the organic EL display device of the present invention, in which FIG. 1A is a schematic plan view, and FIG. 1B is a schematic cross-sectional view taken along line AA ′ in FIG. It is.

  The organic light emitting device 1 shown in FIG. 1 includes a substrate 10 and a pixel that is provided on the substrate 10 and includes three types of subpixels (R subpixel, G subpixel, and B subpixel) having different emission colors. Has been.

  Here, the sub-pixels are arranged in a matrix as shown in FIG. Examples of the arrangement pattern of each sub-pixel include the arrangement pattern shown in FIG. 1A, that is, the arrangement pattern RGBBGRRGBBGR. However, in the present invention, the arrangement pattern of the subpixels is not particularly limited as long as it is adjacent to the subpixels of the same emission color in at least one of the upper, lower, left and right directions.

  By the way, as shown in FIG. 1B, each subpixel is a member in which a lower electrode 11, an organic compound layer 12 (12b, 12g, 12r), and an upper electrode 13 are formed on a substrate 10 in this order. It is. In addition, the organic EL display device 1 of FIG. 1 is provided with an insulating layer (bank) 14 that partitions sub-pixels. Here, as shown in FIG. 1B, the insulating layer 14 is provided at least between the sub-pixels having different emission colors. In this manner, by selectively providing the insulating layer 14, the aperture ratio of each sub-pixel is increased particularly between sub-pixels having different emission colors. Therefore, a sufficient aperture ratio can be obtained even in a small, high-definition organic EL display device having a diagonal size of 3 inches and VGA resolution.

  Next, components of the organic EL display device of the present invention will be described.

  As the substrate 10, an insulating substrate material is used. When the organic EL display device is driven by the active matrix method, as shown in FIG. 1B, the TFT drive circuit 102 and the planarizing film 103 are laminated in this order on the substrate 101. Things are used as substrates.

  The planarizing film 103 is preferably a thin film layer made of a resin material such as polyimide resin or acrylic resin. As shown in FIG. 1A, the TFT drive circuit 102 and the lower electrode 11 are placed at desired positions. A contact hole 104 for electrical connection is provided.

  A lower electrode 11 is formed on the planarizing film 103. The lower electrode 11 is formed by patterning by photolithography so as to correspond to each subpixel on a one-to-one basis. In the case of a top emission type organic EL display device, the lower electrode 11 is made of a light reflective electrode material. Specific examples of the light reflective electrode material include metal materials such as Cr, Al, Ag, Au, and Pt. Here, an electrode material having a high reflectance is preferable because the light extraction efficiency from the upper surface is improved. The lower electrode 11 has a two-layer structure in which a layer made of a light-reflective electrode material and a layer that adjusts a work function such as ITO or IZO are stacked in consideration of carrier injection into the organic compound layer 12. It is good.

  The insulating layer 14 is preferably a layer made of a resin material such as polyimide resin or acrylic resin. Here, the insulating layer 14 is formed in a desired shape by applying a resin material, which is a constituent member, onto the lower electrode 11 by spin coating or the like and then performing patterning by photolithography. In the organic EL display device of the present invention, when patterning the insulating layer 14, the insulating layer 14 is provided between at least different types of subpixels.

  By the way, when the organic compound layer 12 is provided after the insulating layer 14 is provided, it is necessary to avoid a short circuit that occurs between the lower electrode 11 and the upper electrode 13 due to misalignment of the shadow mask or a color mixture between the sub-pixels. is there. For this reason, it is necessary to provide an insulating layer 14 that partitions each subpixel between subpixels having different emission colors. On the other hand, color mixing between sub-pixels cannot occur between sub-pixels having the same emission color. Rather, by omitting the insulating layer 14, the pixel area can be increased by the patterning error when forming the insulating layer 14, so that an increase in aperture ratio can be achieved. However, when the contact hole 104 is provided between the sub-pixels as well as between the sub-pixels having the same emission color as well as between the sub-pixels having different emission colors, an insulating layer is formed above the contact hole 104. 14 is desirable.

  The organic compound layer 12 (12r, 12g, 12b) is a member composed of a single layer or a plurality of layers having a light emitting layer emitting at least red, green, or blue light. However, in the present invention, the layer structure of the organic compound layer 12 is not particularly limited.

  As a constituent material of the organic compound layer (R organic compound layer 12r, G organic compound layer 12g, B organic compound layer 12b) included in each subpixel, an organic light emitting material, a hole injection material, an electron injection material, a hole transport material At least one of electron transport materials can be appropriately selected and used. Further, one layer may be composed of a plurality of materials. However, the R organic compound layer 12r includes a layer having a red light emitting material, the G organic compound layer 12g includes a layer having a green light emitting material, and the B organic compound layer 12b includes A layer having a blue luminescent material is included.

  Among the organic compound layers 12, organic light emitting materials contained in the light emitting layer include triarylamine derivatives, stilbene derivatives, polyarylenes, aromatic condensed polycyclic compounds, aromatic heterocyclic compounds, aromatic heterocyclic condensed compounds, metal complexes. A compound etc. and these single oligo bodies or composite oligo bodies can be used.

  Of the organic compound layer 12, a phthalocyanine compound, a triarylamine compound, a conductive polymer, a perylene compound, an Eu complex, or the like is used as a hole injection / transport material included in the hole transport layer or the hole injection layer. be able to.

Among the organic compound layer 12, as an electron injection / transport material contained in an electron transport layer or an electron injection layer, Alq ₃ in which a trimer of 8-hydroxyquinoline is coordinated to aluminum, an azomethine zinc complex, a distyryl biphenyl derivative system Etc. can be used.

  The film thickness of the organic compound layer 12 is preferably about 0.05 μm to 0.3 μm.

  Specifically, the upper electrode 13 is a layer made of a transparent conductive material, a translucent layer made of a single metal such as aluminum, silver, magnesium, calcium, or an alloy thereof and having a thickness of 2 nm to 50 nm. .

  The organic EL display device of the present invention seals an organic EL element in which a lower electrode 11, an organic compound layer 12, and an upper electrode 13 are laminated in this order, and protects the organic EL element from moisture and oxygen in the atmosphere. Is desirable. As a method for sealing the organic EL element, for example, a method described below can be given.

  That is, in a glove box that is replaced with dry nitrogen and maintained at a dew point of −70 ° C. or lower, a glass sealing cap that has been coated with an ultraviolet curable resin in advance and a substrate that is formed up to the upper electrode 13 are Paste with. And an ultraviolet-ray is irradiated to the ultraviolet curing resin application part, and resin is hardened. By doing so, the organic EL display device of the present invention is completed. As a method for sealing the organic EL element, a method of covering the entire element with an inorganic protective film made of SiN or the like, a protective film in which an inorganic layer and an organic layer are laminated, or the like can be employed.

  The organic EL display device shown in FIG. 1 was produced by the following method.

  A TFT drive circuit 102 was formed on an insulating substrate (base material 101) by a known film formation / patterning method. Next, a planarizing film 103 is formed, and a contact hole 104 is provided at the position shown in FIG. 1A by exposure and development.

  Next, the lower electrode 11 was formed on the planarizing film 103. Specifically, first, a thin film made of Ag was formed to a thickness of 100 nm by sputtering. Next, similarly, a thin film made of IZO was formed to a thickness of 20 nm by sputtering. Next, a pattern was formed in the shape of the lower electrode 11 by a known patterning method.

  Next, a polyimide resin was applied onto the lower electrode 11 by spin coating to form a resin film having a thickness of 1 μm. Next, an opening pattern shown in FIG. 1A was formed on the resin film by exposure and development.

  Next, an R organic compound layer 12r and a B organic layer 12b were formed on the lower electrode 11 by vacuum deposition using the shadow mask shown in FIG. 2A and 2B, the hatched portion indicates the non-opening portion of the mask, and the white portion indicates the stripe-shaped opening portion.

  In this example, a hole injection layer, an organic light emitting layer, an electron transport layer, and an electron injection layer were laminated and formed in this order. Here, N, N′-α-dinaphthylbenzidine (α-NPD) was used as a constituent material of the hole injection layer. Further, a phenanthroline compound was used as a constituent material of the electron transport layer, and a mixture of cesium carbonate and a phenanthroline compound (volume mixture ratio = 0.9: 99.1) was used as a constituent material of the electron injection layer.

On the other hand, in the R organic compound layer 12r, a mixture of Ir complex and 4,4′-N, N′-dicarbazole-biphenyl (CBP) (volume mixing ratio = 18: 82) is used as a constituent material of the light emitting layer. did. In the B organic compound layer 12b, a mixture (volume mixing ratio = 1: 99) of perylene dye and tris [8-hydroxyquinolinate] aluminum (Alq ₃ ) was used as a constituent material of the light emitting layer.

  On the other hand, in this example, the total film thickness of the R organic compound layer 12r and the B organic compound layer 12b was 280 nm and 220 nm, respectively.

Next, a G organic compound layer 12g was formed on the lower electrode 11 by vacuum deposition using the shadow mask shown in FIG. The layer configuration of the G organic compound layer 12g is the same as the layer configuration of the R organic compound layer 12r and the B organic compound layer 12b. On the other hand, in the G organic compound layer 12g, a mixture (volume mixing ratio = 1: 99) of coumarin dye emitting green light and tris [8-hydroxyquinolinate] aluminum (Alq ₃ ) is used as a constituent material of the light emitting layer. It was.

  On the other hand, in this example, the total film thickness of the G organic compound layer 12g was 250 nm.

  Next, Ag was formed into a film by the sputtering method, and the upper electrode 13 having a thickness of 10 nm was formed. The upper electrode 13 is a common electrode provided in common on each organic compound layer (12r, 12g, 12b).

  Finally, in the glove box, a glass sealing cap coated with an ultraviolet curable resin and a substrate on which film formation has been completed are bonded together at the outer periphery of the pixel formation region, and then the resin is cured by irradiating ultraviolet rays. It was. Thus, an organic EL display device was obtained.

  FIG. 3 is a schematic plan view showing a second embodiment of the organic EL display device of the present invention. In this embodiment, the contact hole 104 is provided only between different types of sub-pixels (between the R organic compound layer and the G organic compound layer and between the G organic compound layer and the B organic compound layer). By providing the contact hole 104 only between different types of sub-pixels, the sub-pixels can be opened more efficiently. In this embodiment, the method for forming the members constituting the organic EL display device is the same as that in the first embodiment.

  FIG. 4 is a schematic plan view showing a third embodiment of the organic EL display device of the present invention. In this embodiment, the insulating layer 14 is provided except that the contact hole 104 is not provided between the sub-pixels between the R organic compound layer 12r and the R organic compound layer 12r. In this example, the total film thickness of the G organic compound layer 12g was 110 nm, and the total film thickness of the B organic compound layer 12b was 120 nm. In addition, as shown in FIG. 4, the insulating layer 14 was peeled except between the contact holes 104 only between the sub-pixels of the R organic compound layer 12r. As described above, by selectively peeling the insulating layer 14 in accordance with the total film thickness of the organic compound layers of the respective colors, it is possible to efficiently increase the aperture of the subpixel. In this embodiment, the method for forming the members constituting the organic EL display device is the same as that in the first embodiment.

DESCRIPTION OF SYMBOLS 1 Organic EL display device 10 Substrate 101 Base material 102 TFT drive circuit 103 Flattening film 104 Contact hole 11 Lower electrode 12 Organic compound layer 12r R Organic compound layer 12g G Organic compound layer 12b B Organic compound layer 13 Upper electrode 14 Insulating layer ( bank)

Claims (3)

A substrate,
A plurality of pixels provided on the substrate, and at least two types of sub-pixels having different emission colors; and
In the organic EL display device in which the subpixel includes a lower electrode, an organic compound layer, and an upper electrode,
The subpixel is adjacent to a subpixel of the same emission color in at least one direction;
An organic EL display device comprising an insulating layer between sub-pixels having different emission colors. The substrate has a drive circuit for driving the subpixel;
The drive circuit is electrically connected to the lower electrode through a contact hole;
The organic EL display device according to claim 1, wherein the insulating layer is provided above the contact hole.   The organic EL display device according to claim 1, wherein the contact hole is provided between sub-pixels having different emission colors.

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