KR101990851B1 - Organic Light Emitting Diode Display Device - Google Patents

Abstract

According to one aspect of the present invention, an organic light emitting display includes: a first substrate on which a plurality of pixels are defined; An anode electrode formed for each pixel on the first substrate; A bank layer overlapped with an edge region of the anode electrode, the bank layer being formed at a boundary of the pixel; An organic light emitting layer formed on the anode electrode; A cathode electrode formed on the organic light emitting layer; An encapsulation layer formed on the cathode electrode and including at least one inorganic layer and at least one organic layer; A second substrate facing the first substrate with an adhesive layer therebetween; A black matrix formed on the second substrate and formed at the boundary of the pixel so as to correspond to the bank layer; And a color refiner formed on the pixel defined by the black matrix, the light diffusing layer being formed on the sealing layer to correspond to the black matrix and preventing inter-pixel light leakage.

Description

[0001] The present invention relates to an organic light emitting diode display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting display, and more particularly, to an active organic light emitting display.

With the development of information and communication technology, state-of-the-art flat panel display devices are in the spotlight. Flat panel displays are becoming more thin and more portable. In particular, organic electroluminescent display devices, which are attracting attention as a next-generation liquid crystal display device, are self-luminous devices, and thus there is an advantage that a lightweight thin flat panel device can be realized compared to a liquid crystal display device. Further, the organic light emitting display device is an eco-friendly flat panel display device having a wide viewing angle, excellent contrast ratio, quick response time and low power consumption.

The organic light emitting display device may be divided into a top emission type and a bottom emission type according to the emitting direction of light emitted from the inside. In addition, the organic electroluminescent display device includes a color refiner, which is a kind of color conversion member arranged separately for red, green, and blue for each pixel, using an organic light emitting layer that emits white light as a light source, In the WRGB system in which white light is converted into a desired color and emitted, pixels in which no color refiner is disposed emit white light to realize full color, and RGB system in which a red light emitting layer, a green light emitting layer and a blue light emitting layer are independently arranged in each pixel .

In the WRGB type organic light emitting display device using the top surface light emitting method, since the color refiner is formed on the sealing layer formed for the purpose of preventing damage to the organic light emitting layer, the space between the organic light emitting layer and the color refiner Can be very large.

FIG. 1 is a cross-sectional view illustrating a part of a general organic light emitting display device to which a top surface light emitting method is applied, among WRGB methods.

1, a general organic light emitting display device using a top emission type of WRGB method includes a first substrate 101, a second substrate 102, an anode electrode 110, a bank layer B, The organic EL layer 120, the cathode 130, the sealing layer 140, the adhesive layer 150, the black matrix BM, and the color refiner 160.

The organic light emitting layer 120 and the cathode electrode 130 are sequentially formed on the first substrate 101 and the organic light emitting layer 120 is formed on the cathode electrode 130. [ A sealing layer 140 is formed to prevent damage.

On the second substrate 102, a color refiner 160 is formed on a pixel defined by a black matrix BM and a black matrix BM.

The first substrate 101 and the second substrate 102 are bonded to each other via the adhesive layer 150. Instead of the adhesive layer 150, an organic filler may be filled. At this time, the distance between the color refiner 160 and the organic light emitting layer 120 from which the white light L1 is emitted may be about several tens of μm by the sealing layer 140 and the adhesive layer 150. The distance between the color refiner 160 and the organic light emitting layer 120 from which the white light L1 is emitted or the distance between the color refiner 160 and the cathode electrode 130 is commonly referred to as a cell gap, Light leakage between neighboring pixels may occur through the gap. Also, as the cell gap becomes larger, the inter-pixel light leakage phenomenon may become worse.

As shown, white light L1 from the left pixel may appear to be from the right pixel depending on the viewing angle. When the light leakage phenomenon occurs as described above, accurate gradation representation of each pixel becomes difficult, and distortion of the gradation representation may occur. Furthermore, when a high-resolution organic light emitting display device is implemented, the light leakage phenomenon can be further exacerbated because the pixel width is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic light emitting display device capable of preventing inter pixel light leakage.

According to an aspect of the present invention, there is provided an organic light emitting display including: a first substrate on which a plurality of pixels are defined; An anode electrode formed for each pixel on the first substrate; A bank layer overlapped with an edge region of the anode electrode, the bank layer being formed at a boundary of the pixel; An organic light emitting layer formed on the anode electrode; A cathode electrode formed on the organic light emitting layer; An encapsulation layer formed on the cathode electrode and including at least one inorganic layer and at least one organic layer; A second substrate facing the first substrate with an adhesive layer therebetween; A black matrix formed on the second substrate and formed at the boundary of the pixel so as to correspond to the bank layer; And a color refiner formed on the pixel defined by the black matrix, the light diffusing layer being formed on the sealing layer to correspond to the black matrix and preventing inter-pixel light leakage.

According to the present invention, an inter-pixel light leakage can be prevented by forming a light blocking layer corresponding to a black matrix.

Further, according to the present invention, it is possible to prevent inter-pixel light leakage and enable accurate gradation expression in each pixel.

In addition, according to the present invention, an inter-pixel light leakage can be prevented, and a high-resolution organic light emitting display device can be realized.

1 is a cross-sectional view of a conventional organic light emitting display device;
2 is a cross-sectional view illustrating an organic light emitting display device according to an embodiment of the present invention;
3 is a cross-sectional view illustrating a light blocking layer according to another embodiment of the present invention; And
4 is a cross-sectional view illustrating a light blocking layer according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view illustrating an organic light emitting display according to an exemplary embodiment of the present invention.

2, an organic light emitting display according to an exemplary embodiment of the present invention includes a first substrate 201, a second substrate 202, an anode electrode 210, a bank layer B, A light emitting layer 220, a cathode electrode 230, an encapsulating layer 240, a light blocking layer 250, an adhesive layer 260, a black matrix BM and a color refiner 270.

First, the first substrate 201 and the second substrate 202 may be formed of glass, a transparent flexible material, or an opaque insulating material. The transparent flexible material may be polyimide, polyetherimide (PEI), and polyethyeleneterephthalate (PET). The flexible substrate may be formed on a rigid substrate, such as glass, and then removed from the rigid substrate through a process such as laser release.

Next, an anode electrode 210 is formed on the first substrate 201. The anode electrode 210 is an electrode for supplying holes, and may be formed of a material having a generally large work function. The material having a large work function, and the conductive material is typically a conductive oxide. They are mostly transparent and called transparent conductive oxide (TCO). Examples of transparent conductive oxides include indium tin oxide (ITO), indium zinc oxide (IZO), and indium tin zinc oxide (ITZO).

Next, the bank layer B is formed on the first substrate 201, partially overlapping with the anode electrode 210. The bank layer B overlaps the edge of the anode electrode 210 and is formed at the boundary of each pixel and defines an area where the anode electrode 210 contacts the organic light emitting layer 220. The region where the anode electrode 210 contacts the organic light emitting layer 220 is a light emitting region, and the bank layer B defines a light emitting region of each pixel.

Further, the bank layer (B) makes the light emission of the organic light emitting layer (220) uniform. Charges, including electrons and holes, tend to be distributed more at the junctions of the conductors. In the anode electrode 210, there is an apex in the edge region. When charges are added to the apex, more light is emitted from the organic light emitting layer 210 in the region corresponding to the apex, and less light is emitted in the other region. Nonuniformity may occur. However, since the bank layer B covers the edge region of the anode electrode 210, it is possible to prevent the anode electrode 210 from being in contact with the organic light emitting layer 220 even when charges are accumulated in the edge region, The lifetime of the organic light emitting layer 220 can be prevented from being reduced.

Next, an organic light emitting layer 220 is formed on the bank layer (B) and the anode electrode 210. Holes are supplied to a region where the organic light emitting layer 220 contacts the anode electrode 210 by the bank layer B and electrons supplied from the cathode electrode 230 meet the holes to form a band of a material of the organic light emitting layer 220 Light energy is emitted as much as the band gap energy. That is, no light is emitted from the organic light emitting layer 220 corresponding to the bank layer B. However, the organic light emitting layer 220 may not be formed on the bank layer B.

The organic light emitting layer 220 emits white light L2 and the white light L2 sequentially passes through the cathode electrode 230, the sealing layer 240 and the adhesive layer 260, The light is converted into light of a desired color for each pixel and emitted to the outside through the second substrate 202. In this process, since the sealing layer 240 and the adhesive layer 260 reach several tens of microns due to the purpose of formation and the material, some of the white light L2 can not pass through the color refiner 270, To the color refiner 270 of the pixel. However, the white light L2 traveling toward the color refiner 270 of the neighboring pixel is blocked by the light blocking layer 250 and does not enter the neighboring pixel. This can prevent the light leakage phenomenon between adjacent pixels.

Next, the cathode electrode 230 is formed on the organic light emitting layer 220. The cathode electrode 230 may be formed of any one of silver (Ag), magnesium (Mg), aluminum (Al), and copper (Cu) , A metal having a low work function, and an alloy thereof. In addition, the cathode electrode 230 may be formed as a thin film to allow light to be emitted to the outside, and may be formed thin to a thickness of several hundreds of ohms or less.

The cathode electrode 230 is formed of the thin film as described above in order to increase the transmittance of the white light L2 emitted from the organic light emitting layer 220. As a result, the resistance of the cathode electrode 230 may increase and the electrical conductivity may be deteriorated. Therefore, the auxiliary electrode and the cathode electrode 230 are electrically connected to each other in the non-light emitting region to lower the resistance, thereby enabling normal driving.

Next, an encapsulating layer 240 is formed on the cathode electrode 230. The sealing layer 240 prevents the penetration of foreign substances that may damage moisture and organic matter by the organic light emitting layer 220 and can prevent the organic light emitting layer 220 from being damaged.

The sealing layer 240 may be a multilayer in which inorganic and organic materials are alternately formed to prevent penetration of moisture and foreign matter. The inorganic material may be formed by thermal vapor deposition or chemical vapor deposition, and since it has no planarization property, it may be formed in the same shape as the concavo-convex of the surface to be formed. Therefore, if there is a foreign substance on the surface to be formed, a thin film is formed along the surface of the foreign matter, and a thin film is not formed densely and cracks may occur around the foreign matter. Cracks may deteriorate due to driving of the organic light emitting display device and may become larger.

On the other hand, the organic material is formed in a viscous liquid state, for example, by a screen printing method, and then sintered at a high temperature to be cured, so that the planarization property is high. Therefore, even when there is foreign matter or irregularities on the surface to be formed, the upper surface is formed flat. Accordingly, the sealing layer 240 may be formed of multiple layers in which organic and inorganic materials are alternately formed in order to minimize the occurrence of cracks.

As described above, since the sealing layer 240 can be generally formed of multiple layers, the sealing layer 240 can have a thickness of several tens of micrometers. Thus, the encapsulation layer 240 may cause the cell gap to increase.

Next, a light blocking layer 250 is formed on the sealing layer 240. The light blocking layer 250 may be formed as a single layer or a multilayer. When the light blocking layer 250 is formed as a single layer as shown in the drawing, the light blocking layer 250 may be formed of a material having a low reflectance such as resin or graphite in order to block the progress of light and prevent reflection. More preferably, the light blocking layer 250 can use a material having an optical density of 3.5 or more and a reflectance of 10% or less. In addition, the light blocking layer 250 may have a thickness of 1 μm or less. Since the width of the light blocking layer 250 may be equal to or smaller than the bank layer B, the light leaked through the color refiner 270 of the pixel may not be blocked and only the light leaked to the neighboring pixels may be blocked.

Since the light blocking layer 250 is formed on the sealing layer 240, light leaking from the middle region of the cell gap to neighboring pixels can be prevented at the maximum. The light blocking layer 250 may be formed in a region corresponding to the black matrix BM and may be formed in the same matrix as the black matrix BM.

The light blocking layer 250 may be formed of any one of photolithography, screen printing, and imprinting, or may be formed using a shadow mask. When the light blocking layer 250 is formed of multiple layers, the multiple layers may be formed and patterned at the same time, but the present invention is not limited thereto, and may be variously formed according to materials and processes.

Next, an adhesive layer 260 is formed on the sealing layer 240 and the light blocking layer 250. The adhesive layer 260 may be formed to adhere the first substrate 201 and the second substrate 202 and may be an adhesive material or fill a space between the first substrate 201 and the second substrate 202 Lt; / RTI > The sum of the thickness of the sealing layer 240 and the thickness of the adhesive layer 260 is a thickness corresponding to the cell gap and can reach about several tens of microns. In an organic light emitting display device having a resolution of 300 ppi (pixel per inch), for example, one pixel has a width of about 83 袖 m and a cell gap of several tens 袖 m, the pixel width and the cell gap length become similar , In the case of an organic light emitting display having a resolution higher than 300 ppi, the cell gap distance can be made larger than the pixel width.

As described above, when the distance of the cell gap to the width of the pixel is relatively large, it is necessary to reduce the thickness of the sealing layer 240 and the adhesive layer 260 because light often leaks to neighboring pixels. However, in the case of the sealing layer 240, it is necessary to form a multilayer thin film, and the adhesive layer 260 may also have a limitation in reducing the thickness in order to increase the reliability of the bonding. Accordingly, when the light blocking layer 250 is formed on the sealing layer 240 and the light leakage of the neighboring pixel is blocked, the thicknesses of the sealing layer 240 and the adhesive layer 260 can be maintained as they are.

Next, a black matrix (BM) is formed on the second substrate 202. The black matrix BM may be formed at the boundary of the pixel on the second substrate 202 and correspond to the bank layer B. [ In addition, the black matrix BM can be formed to prevent light of each pixel from leaking to neighboring pixels, and to allow each pixel to express an accurate gradation. However, since the black matrix BM is formed on the second substrate 202, it can not block light traveling to neighboring pixels in the cell gap under the black matrix BM. When the black matrix (BM) is widely formed, the aperture ratio is reduced and a problem of luminance drop occurs. Therefore, it is difficult to prevent inter pixel light leakage due to the black matrix (BM) alone.

Next, a color refiner 270 is formed on each pixel defined by the black matrix BM on the second substrate 202. [ For example, the color refiner 270 may be divided into a red color refiner, a green color refiner, and a blue color refiner, and may be sequentially arranged in the row direction in each pixel. Color refiners of the same color can be arranged in the column direction.

3 is a cross-sectional view illustrating a light blocking layer 250 according to another embodiment of the present invention.

As shown in FIG. 3, the light blocking layer 250 according to another embodiment of the present invention includes a first auxiliary layer 251 and a metal layer 252.

In FIG. 2, the light blocking layer 250 is formed as a single layer, and is formed of a material including resin and graphite to block light traveling in the light leakage direction, have.

However, in FIG. 3, the light blocking layer 250 is formed as a double layer, and may include the first auxiliary layer 251 and the metal layer 252. The first auxiliary layer 251 and the metal layer 252 are stacked in this order so that the first auxiliary layer 251 is formed first and the metal layer 252 is formed on the first auxiliary layer 251 But may be formed in the opposite order without limitation.

Further, the first auxiliary layer 251 may be formed of a single layer, but may also be formed of a plurality of layers. Here, the first auxiliary layer 251 may be a transparent conductive oxide which is the same material as the anode electrode 210. In addition, the first auxiliary layer 251 may include any one of aluminum oxide, titanium oxide, and tungsten oxide. The metal layer 252 may comprise any one of tungsten, molybdenum, titanium, and chromium,

As described above, when the light blocking layer 250 is formed as a double layer, the thickness of the light blocking layer 250 is increased, and light blocking can be more reliably prevented. That is, since the metal layer 252 is formed on the first auxiliary layer 251, leakage of light to the upper portion of the light blocking layer 250 can be more reliably prevented. In addition, the first auxiliary layer 251 can reduce the reflectance of the metal layer 252, thereby preventing reflection of light from the bottom of the metal layer 252.

4 is a cross-sectional view illustrating a light blocking layer 250 according to another embodiment of the present invention.

4, the light blocking layer 250 according to another embodiment of the present invention includes at least one second auxiliary layer 253, at least one third auxiliary layer 254, (255). The order of stacking the second auxiliary layer 253, the third auxiliary layer 254 and the metal layer 255 is not limited, but preferably the second auxiliary layer 253, the third auxiliary layer 253, 254 and a metal layer 255 in this order.

The second auxiliary layer 253 and the third auxiliary layer 254 can reduce the reflectance of the metal layer 255. [ The second auxiliary layer 253 and the third auxiliary layer 254 may be formed of fluorine based compounds including magnesium fluoride (MgF2) and lithium fluoride (LiF), and ceramics such as silicon oxide (SiOx) And the metal layer 255 may include any one of tungsten, molybdenum, titanium, and chromium.

The second auxiliary layer 253 and the third auxiliary layer 254 may be preferably a material having a small dielectric constant and the metal layer 255 preferably has a small reflectivity and a complex refractive index expressed by the following formula (1) (Extinction coefficient) value, which is an imaginary part of the image, can be large.

 N = n + ik (1)

The extinction coefficient is an apparent optical characteristic in which the light is extinguished according to the depth, which means the degree of light absorption. Therefore, the larger the extinction coefficient is, the smaller the reflectance and the greater the light absorption rate.

The second auxiliary layer 253 and the third auxiliary layer 254 which can reduce the reflectivity of the metal layer 255 are formed in the light blocking layer 250. In this case, The light blocking layer 250 can be prevented from proceeding to a neighboring pixel. The metal layer 255 is formed on the second auxiliary layer 253 and the third auxiliary layer 254 to reliably prevent light from leaking to the upper portion of the light blocking layer 250. Accordingly, the light blocking layer 250 can prevent the neighboring inter pixel light leakage phenomenon.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

201: first substrate 202: second substrate
210: anode electrode 220: organic light emitting layer
230: cathode electrode 240: sealing layer
250: light blocking layer 260: adhesive layer
270: color refiner B: bank layer
BM: Black Matrix

Claims (11)

A first substrate on which a plurality of pixels are defined;
An anode electrode formed for each pixel on the first substrate;
A bank layer overlapped with an edge region of the anode electrode, the bank layer being formed at a boundary of the pixel;
An organic light emitting layer formed on the anode electrode;
A cathode electrode formed on the organic light emitting layer;
An encapsulation layer formed on the cathode electrode and including at least one inorganic layer and at least one organic layer;
A second substrate facing the first substrate with an adhesive layer therebetween;
A black matrix formed on the second substrate and formed at the boundary of the pixel so as to correspond to the bank layer;
A color refiner formed in the pixel defined by the black matrix; And
And a light blocking layer formed corresponding to the black matrix and preventing inter-pixel light leakage,
Wherein the light blocking layer is spaced apart from the second substrate and is in contact with an upper surface of the sealing layer,
Wherein the light blocking layer comprises at least one metal layer and at least one first auxiliary layer. The method according to claim 1,
Wherein the light blocking layer comprises one of a resin and graphite. 3. The method of claim 2,
Wherein the light blocking layer has an absorbance of 3.5 or more and a reflectance of 10% or less. 3. The method of claim 2,
Wherein the light blocking layer has a thickness of 1 占 퐉 or less. delete The method according to claim 1,
Wherein the light blocking layer is a double layer including one metal layer and one first auxiliary layer, and the thickness of the light blocking layer is 0.5 占 퐉 or less. The method according to claim 1,
Wherein the metal layer comprises any one of tungsten, molybdenum, titanium, and chromium. The method according to claim 1,
Wherein the first auxiliary layer comprises any one of indium tin oxide, indium zinc oxide, indium tin zinc oxide, aluminum oxide, titanium oxide and tungsten oxide. The method according to claim 1,
Wherein the first auxiliary layer comprises at least one second auxiliary layer, and at least one third auxiliary layer. 10. The method of claim 9,
Wherein the second auxiliary layer and the third auxiliary layer are any one of a fluorine-based material and a silicon-based material. delete

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