KR101972306B1 - Organic light emitting display device - Google Patents

Abstract

An organic light emitting element arranged on the plurality of pixels, and a plurality of pixels arranged on the upper substrate, the organic light emitting element being disposed on a boundary portion between the plurality of pixels, And a black matrix having an opening facing each of the pixels, wherein the opening and each of the pixels may have different shapes.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light-

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to an organic light emitting diode (OLED) display, and more particularly, to an organic light emitting diode (OLED) display capable of improving flexible display and reducing outdoor light reflectance.

2. Description of the Related Art In recent years, there is an increasing demand for a flat panel display device having excellent luminous efficiency, luminance, viewing angle, and response speed.

Of the flat panel display devices, a liquid crystal display device requires a backlight as a separate light source and has technical limitations in terms of brightness, contrast ratio, and viewing angle.

Accordingly, there is an increasing interest in an organic light emitting display device which is self-emitting and does not require a separate light source and is relatively excellent in brightness, contrast ratio, and viewing angle.

FIG. 1 is a view briefly showing a structure of an organic light emitting display according to a related art, and FIG. 2 is a view schematically showing a light emitting structure of an organic light emitting device.

1 and 2, an OLED display according to a related art includes a lower substrate 10, a plurality of thin film transistors provided on the lower substrate 10, and a metal electrode 20.

It also includes gate lines, data lines, power supply lines, emission signal lines, and reset lines.

The thin film transistor includes a plurality of switching thin film transistors and a driving thin film transistor for switching the light emission of each pixel. In addition, a storage capacitor Cst for charging a current supplied to the organic light emitting diode 30 is formed on the lower substrate 10.

The organic light emitting device 30 is formed on the thin film transistor and the metal electrode 20 and the lower substrate 10 and the upper substrate 40 are bonded together using an encapsulant and an adhesive.

The organic light emitting element 30 formed on the plurality of pixels emits red, green, and blue color light for full color implementation.

On the upper substrate 40, a polarizing film 50 is formed to enhance the visibility of the color image displayed in each pixel. Here, the polarizing film 50 may be configured to include a quarter wave plate and a half wave plate.

The organic light emitting device 30 shown in FIG. 2 includes an anode electrode 31, a hole injection layer 32, an organic light emitting layer 33, an electron injection layer 34; And a cathode electrode 35 are stacked in this order.

When electrons generated in the cathode electrode 35 and holes generated in the anode electrode 31 are injected into the light emitting layer 33, injected electrons and holes are coupled to generate an exciton. Then, the exciton falls from the excited state to the ground state, causing light emission, thereby displaying an image.

The OLED display according to the related art uses a polarizing film 50 formed on the upper substrate 40 to prevent transmission of external light reflected from a pixel, thereby increasing an ambient contrast ratio (ACR).

However, there is a problem in that the manufacturing cost is increased due to the application of the polarizing film 50, and there is a problem that the brightness of the image is lowered due to the low light transmittance of the polarizing film 50 and the display quality is deteriorated.

Particularly, when the organic light emitting display device is implemented as a flexible display device, there is a merit of being able to freely bend, but there is a problem that flexibility of bending is lowered due to application of the polarizing film 50.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has the following technical problems.

Disclosure of Invention Technical Problem [8] The present invention provides an organic light emitting display device having a polarizing film and a flexible display device.

An object of the present invention is to provide an organic light emitting display device which improves display quality by increasing the color reproduction rate of a pixel.

Other features and advantages of the invention will be set forth in the description which follows, or may be obvious to those skilled in the art from the description and the claims.

According to an aspect of the present invention, there is provided an organic light emitting diode display comprising: an upper substrate and a lower substrate which are adhered to each other; a bank arranged on the lower substrate to partition a plurality of pixels; A light emitting element, a black matrix disposed on the upper substrate and having a light shielding portion disposed at a boundary portion of the plurality of pixels, and an opening facing each pixel, wherein the opening and each pixel have different shapes Lt; / RTI >

The plurality of pixels may have a rhombic or hexagonal shape.

The opening may have a cross shape.

According to the solution of the above-mentioned problems, the present invention has the following effects.

The OLED display of the present invention can easily implement a flexible display device by eliminating the polarizing film. The present invention includes a color filter and a black matrix instead of the polarizing film. Further, the black matrix has openings overlapping the respective pixels, and the shape of the openings is designed differently from the shape of each pixel, so that the luminance viewing angle can be increased.

In addition to the effects of the present invention mentioned above, other features and advantages of the present invention will be described below, or may be apparent to those skilled in the art from the description and the description.

1 is a view schematically showing a structure of an OLED display according to a related art.
2 is a view schematically showing a light emitting structure of an organic light emitting device.
3 is a cross-sectional view of an OLED display according to an embodiment of the present invention.
4 schematically shows the path of light emitted from the organic light emitting element.
5 is a plan view showing a plurality of pixels and a black matrix according to an embodiment of the present invention.
5 is a plan view showing a plurality of pixels and a black matrix BM according to an embodiment of the present invention.
6 is an enlarged plan view of the first through third pixels and the black matrix shown in FIG.
7 is a plan view showing a plurality of pixels and a black matrix according to another embodiment of the present invention.

The meaning of the terms described herein should be understood as follows. The word " first, " " second, " and the like, used to distinguish one element from another, are to be understood to include plural representations unless the context clearly dictates otherwise. The scope of the right should not be limited by these terms. It should be understood that the terms "comprises" or "having" does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. It should be understood that the term " at least one " includes all possible combinations from one or more related items. For example, the meaning of " at least one of the first item, the second item and the third item " means not only the first item, the second item or the third item, but also the second item and the second item among the first item, Means any combination of items that can be presented from more than one. The term " on " means not only when a configuration is formed directly on top of another configuration, but also when a third configuration is interposed between these configurations.

Hereinafter, preferred embodiments of the organic light emitting display according to the present invention will be described in detail with reference to the accompanying drawings.

In this specification, a top emission type organic light emitting display device refers to an organic light emitting display device in which light emitted from an organic light emitting device is emitted to an upper part of the organic light emitting display device, Means an organic light emitting display device that emits in the direction of the top surface of a substrate on which a thin film transistor for driving the organic light emitting display device is formed.

In this specification, a flexible display device refers to a flexible display device, and includes a display device such as a bendable display device, a rollable display device, an unbreakable display device, a foldable display device, and the like. Here, the flexible organic light emitting display device is one example of various flexible display devices.

3 is a cross-sectional view of an OLED display according to an embodiment of the present invention.

Referring to FIG. 3, an OLED display according to an embodiment of the present invention is implemented in a top emission scheme.

Specifically, the organic light emitting display according to the embodiment includes an upper substrate EG and a lower substrate SUB which are adhered to each other, a thin film transistor provided on the lower substrate SUB, A moisture barrier layer (MPB) covering the organic light emitting device OLED, and a color filter (not shown) provided on the upper substrate EG. The organic light emitting device OLED includes a plurality of pixels BK, CF).

The upper substrate EG and the lower substrate SUB are made of a transparent flexible material. For example, the material of the upper substrate EG and the lower substrate SUB may be selected from the group consisting of polyethylene naphthalate, polyethylene terephthalate, polycarbonate, polyethersulfone, and the like. And metal foil including stainless steel (SUS: Stainless Steel) or the like may be used.

The thin film transistor includes a switching thin film transistor (not shown) and a driving thin film transistor DT connected to the switching thin film transistor. Here, the driving thin film transistor DT is connected to the organic light emitting element OLED.

The switching thin film transistor is disposed in a region where a gate line and a data line cross each other. The switching thin film transistor functions to select pixels.

The driving thin film transistor DT includes a gate electrode DG connected to the drain electrode of the switching thin film transistor and a source electrode DS connected to the semiconductor layer DA and the driving current transmission line and a drain electrode DD. The drain electrode DD of the driving thin film transistor DT is connected to the anode electrode ANO of the organic light emitting element OLED. This driving thin film transistor DT serves to drive the organic light emitting element OLED of the pixel selected by the switching thin film transistor.

Meanwhile, a top gate structure and a bottom gate structure can be applied to the thin film transistor DT according to the embodiment of the present invention. However, for convenience of description, only the top gate structure will be described in the embodiment of the present invention.

The semiconductor layer DA of the switching thin film transistor DT and the semiconductor layer DA of the driving thin film transistor DT are formed on the buffer layer BUF of the substrate SUB first, (DG) is formed so as to overlap the center portion of the semiconductor layers (DA). The source electrode DS and the drain electrode DD are formed on the insulating film IN covering the gate electrodes DG. The source electrode DS and the drain electrode DD are connected to the semiconductor layers DA through the insulating film IN and the contact hole penetrating the gate insulating film GI.

The protective film PAS and the planarizing film PL are coated on the substrate SUB on which the driving thin film transistor DT and the switching thin film transistor are formed. A contact hole exposing the drain electrode DD of the driving thin film transistor DT is formed in the passivation film PAS and the planarization film PL, and the anode electrode ANO of the organic light emitting element OLED through the contact hole And is electrically connected to the drain electrode DD of the driving thin film transistor DT.

A bank BK is formed on a substrate SUB excluding a plurality of pixels in the display region. These banks BK serve to divide a plurality of pixels.

Meanwhile, an organic light emitting diode (OLED) is disposed in the pixel. The organic light emitting diode OLED includes an anode electrode ANO connected to the driving thin film transistor DT and made of a reflective material, an organic layer OLE provided on the anode electrode ANO and having an organic light emitting layer, And a cathode electrode (CAT) deposited on the organic layer (OLE) and made of a transflective material.

The organic light emitting diode OLED may emit red, green or blue color light or emit ultraviolet (UV) light or white light to display a full color image. That is, the organic light emitting diode OLED may be any one of a red organic light emitting diode (OLED), a green organic light emitting diode (OLED), a blue organic light emitting diode (OLED), and a white organic light emitting diode (OLED). The light emitted from the organic light emitting diode OLED is emitted to the upper substrate EG via the color filter CF.

A moisture barrier layer (MPB) is deposited on the substrate (SUB) including the organic light emitting device (OLED). The moisture barrier layer (MPB) may have a single layer or a multilayer structure in which an inorganic film and an organic film are selectively laminated.

In the organic light emitting diode display having the above structure, the front film FS is applied to the front surface of the lower substrate SUB in the display area, and the lower substrate SUB and the upper substrate EG ).

On the upper substrate EG, a plurality of color filters CF are formed corresponding to the plurality of pixels. The color filter CF overlaps with the red color filter CF1 overlapping the red organic light emitting device OLED, the green color filter CF2 overlapping with the green organic light emitting device OLED, and the blue organic light emitting device OLED And a blue color filter CF3. Such a color filter (CF) plays the role of improving the color purity and realization of a full color image.

A black matrix BM is disposed at the boundary of the plurality of color filters CF. The black matrix BM has a light shielding portion located on the upper substrate and located at a boundary portion of a plurality of pixels, and an opening OP opposed to each pixel. The black matrix BM absorbs light incident from the outside. Such a black matrix BM prevents color mixing between adjacent pixels to increase color purity.

4 schematically shows a path of light emitted from the organic light emitting device OLED.

As described above, the OLED display of the present invention can easily implement a flexible display device by deleting the polarizing film according to the related art. However, instead of deleting the polarizing film applied to the prior art, the present invention uses a black matrix (BM) disposed at a boundary portion between a plurality of color filters (CF) and a plurality of color filters (CF) There may be a problem of deterioration.

Specifically, in the present invention, as shown in FIG. 4, the black matrix BM is provided on the upper substrate EG, thereby increasing the gap between the upper substrate EG and the lower substrate SUB. Accordingly, a part of the light emitted from the organic light emitting diode OLED is blocked by the black matrix BM, and therefore, the luminance viewing angle? Is lowered. Such a decrease in the viewing angle? Is caused to be larger as the width of the black matrix BM increases.

Therefore, the embodiment of the present invention differs from the design of the black matrix (BM) in order to solve the problem of the decrease in the viewing angle?. This will be described in detail as follows.

The present invention is not limited to the shape of each pixel, and can be applied to a pixel rendering structure of a conventional organic light emitting display device.

Conventionally, various structures have been proposed to enhance the aperture ratio and the reliability of the rendering structure of the organic light emitting display device. The reasons are briefly described as follows.

In the production of an organic light emitting display, an organic layer (OLE) of an organic light emitting diode (OLED) is usually formed through a vacuum thermal deposition method.

In the vacuum thermal deposition method, the organic material constituting the organic layer (OLE) is placed in an evaporation source having an outlet, and the evaporation source is heated in a chamber in which the vacuum is maintained to discharge the evaporated organic material through the outlet. At this time, the emitted organic material is deposited on the lower substrate SUB.

When a plurality of organic layers (OLE) having a desired pattern are used, a shadow mask having a plurality of openings (OP) patterns is used. First, a shadow mask having a plurality of openings OP is positioned close to the lower substrate SUB. Then, the organic material is deposited on the lower substrate SUB through the shadow mask to form an organic layer (OLE) having a specific pattern shape and having a specific pattern.

Meanwhile, in recent years, studies on organic light emitting display devices realized in full color have been actively conducted, and organic layers (OLE) formed by shadow masks emit red, green, and blue colors, respectively.

At this time, the organic layer (OLE) emitting different colors should be spaced apart from each other by a predetermined distance or more in order to prevent the shadowing phenomenon that the boundary between the adjacent organic layer (OLE) patterns that may occur during the manufacturing process is blurred.

The separation distance between the organic layer (OLE) patterns does not substantially emit light, resulting in a dead zone.

However, in order to realize a high color reproduction rate and a high resolution, it is necessary to form more pixels per unit area, and to reduce the dead zone, it is desirable. However, it is difficult to reduce the dead zone due to limitations of the process technology. Accordingly, a pixel rendering structure that is easy to realize a high color reproduction rate and a high resolution has been continuously studied.

5 is a plan view showing a plurality of pixels and a black matrix BM according to an embodiment of the present invention. 6 is an enlarged plan view of the first through third pixels and the black matrix shown in FIG.

Referring to FIGS. 5 and 6, the plurality of pixels P include first to third pixels P1 to P3 that display different colors. In this embodiment, the center of each of the first to third pixels P1 to P3 adjacent to each other is triangular, and the three sides of the triangle are designed to have different lengths.

Specifically, the OLED display according to the embodiment of the present invention includes a plurality of pixels P1 to P3.

The plurality of pixels include a plurality of first pixels (P1) emitting light of a first color, a plurality of second pixels (P2) emitting light of a second color different from the first color, And a plurality of third pixels P3 that emit light of a third color different from the color of the second color.

The first to third colors may be mixed to realize white light. In the embodiment of the present invention, green, blue, and red may be used. However, the present invention is not limited thereto, and may be yellow, cyan, and magenta.

The first color has a high color index map, and the first color is green since the color most perceived by a person when the pixels are implemented in green, blue, and red is green.

When the pixels are implemented in green, blue, and red, the organic luminescent material that constitutes the second color of blue is the material with the lowest lifetime.

Each of the pixels is formed in a hexagonal structure and arranged in a hexagonal structure.

5, since the pixels are arranged in a hexagonal shape, they are arranged in a zigzag manner along a first direction X that is the direction of the arrow. In the first direction X, And are arranged in a straight line along a second direction Y which is a right angle and which is a longitudinal direction. The first pixel P1, the second pixel P2, and the third pixel P3 are sequentially arranged with respect to one straight line in the second direction Y. [ The other straight line adjacent to the straight line in the first direction X also has a structure in which the first to third pixels P3 to P3 are arranged in order. At this time, by arranging only the pixels of different colors around one pixel, the centers of one first pixel P1, one second pixel P2, and one third pixel P3, which are adjacent to each other, .

The structure in which the pixels are arranged in the hexagonal shape is higher than the structure in which the pixels are arranged in the rectangular shape.

In such arrangement of pixels, pixels of the same color are arranged one by one along the first direction (X), and pixels of the same color are arranged one by one along the second direction (Y).

In addition, the centers of one first pixel P1, one second pixel P2, and one third pixel P3, which are adjacent to each other, are triangular. At this time, the length of one of the three sides of the triangle becomes shorter than the remaining sides. According to the embodiment of the present invention shown in Fig. 5, all three sides of the triangle have different lengths.

Hereinafter, an embodiment of the present invention in which the luminance viewing angle? Can be increased while using a black matrix (BM) will be described.

Referring to FIG. 6, the black matrix BM has an opening OP overlapping each pixel. The present invention is designed such that the shape of the opening OP differs from the shape of each pixel in order to improve the luminance viewing angle? In the left-right direction and the up-and-down direction. The area of the opening OP is designed to be larger than the area of each pixel.

Specifically, the opening OP of the black matrix BM has a cross shape. That is, the opening OP of the black matrix BM is divided into a first opening OP overlapping each pixel and a second opening OP overlapping each pixel. Accordingly, the first opening OP overlaps with the organic light emitting element OLED, and the second opening OP does not overlap with the organic light emitting element OLED.

Particularly, the present invention is designed such that the width of the second opening OP is not uniform. That is, the width of the second opening OP is largest at both ends in the horizontal direction and at both ends in the vertical direction. On the other hand, the width of the second opening OP is designed to be relatively small at both ends in the diagonal direction.

The present invention increases the amount of light in the left and right direction and in the up and down direction in the light emitted from the organic light emitting device OLED. Therefore, the present invention improves the luminance viewing angle? In the left-right direction and the up-and-down direction.

In the example shown in Figs. 5 and 6, each pixel is formed in a hexagonal structure, but the structure of each pixel may have a rhombic shape as shown in Fig. In this case as well, the opening OP of the black matrix BM has a cross shape to improve the luminance viewing angle?.

As described above, the OLED display of the present invention can easily implement a flexible display device by eliminating the polarizing film. The present invention has a color filter (CF) and a black matrix (BM) instead of the polarizing film. In addition, the black matrix BM has an opening OP overlapping each pixel, and the shape of the opening OP can be designed differently from the shape of each pixel to increase the luminance viewing angle [theta].

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. Will be clear to those who have knowledge of. Therefore, the scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention.

MPB: moisture barrier film
OP: opening of black matrix
EG: upper substrate
SUB: Lower substrate
FS: front film
CF: color filter
BK: Bank
BM: Black Matrix

Claims (7)

An upper substrate and a lower substrate bonded to each other;
A bank disposed on the lower substrate to partition a plurality of pixels;
An organic light emitting element disposed in the plurality of pixels;
A black matrix disposed on the upper substrate as a whole and having a light shielding portion that does not overlap with the organic light emitting diode, and an opening facing each pixel in the plurality of pixels,
Wherein the plurality of pixels include first to third pixels that display different colors,
The center of each of the first to third pixels adjacent to each other is triangular,
Wherein the opening portion is divided into a first opening portion overlapping each pixel and a second opening portion surrounding the pixel,
Wherein the width of the second opening is the largest at both ends in the horizontal direction and at both ends in the vertical direction and the smallest at both ends in the diagonal direction. The method according to claim 1,
Wherein the opening and each pixel have different shapes. The method according to claim 1,
Wherein the plurality of pixels have a rhombic or hexagonal shape. The method according to claim 1,
The three sides of the triangle have different lengths. delete delete The method according to claim 1,
Wherein the opening has a cross shape.

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