KR100756865B1 - Oganic electro luminescence display having organic luminescence layers with different thickness by r,g,b pixels and method of manufacturing the same - Google Patents

Abstract

A manufacturing method of an organic electro-luminescence display device having organic luminescence layers with different thicknesses by R,G,B pixels and a manufacturing method thereof are provided to reduce the number of masks and a photolithography process by forming an anode with only two masks. A manufacturing method of an organic electro-luminescence display device includes the steps of: forming a metal film(115) on a substrate(110) having separated R, G, B pixel regions; forming a buffer layer on the metal film(115); forming buffer patterns(120a,120b,120c) with different thicknesses by performing photolithography and etching processes on the buffer layer with a halftone mask(200); forming a metal pattern by etching the metal film(115) in the shape of the buffer patterns(120a,120b,120c); forming a transparent conductive layer on the substrate(110) having the buffer patterns(120a,120b,120c) and the metal pattern; forming an anode by etching the transparent conductive layer by R, G, B pixels; forming an insulating layer having an opening for exposing an upper part of the anode; selectively forming R, G, B organic luminescence layers in the opening; and forming a cathode on the organic luminescence layer and the insulating layer.

Description

Organic electroluminescent display having an organic light emitting layer having a different thickness for each pixel and a method for manufacturing the organic light emitting display device having a different thickness by R, G, B pixels and method of manufacturing the same}

1 is a cross-sectional view showing a general organic light emitting display device.

2 to 4 are cross-sectional views of respective processes for explaining a method of manufacturing an organic light emitting display device according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

110: insulating substrate 115: metal film

116: metal pattern 120: buffer layer

120a, 120b, 120c: buffer pattern 122: transparent conductive layer

125a, 125b, 125c: anode electrode 130: insulating film

130R, 130G, 130B: R, G, B opening 135R, 135G, 135B: R, G, B organic light emitting layer

140: cathode electrode 200: halftone mask

210: light shielding pattern 220: first transflective pattern

230: second transflective pattern

The present invention relates to an organic light emitting display device and a method for manufacturing the same, and more particularly to an organic light emitting display device having a uniform image quality and a method of manufacturing the same.

In general, an organic light emitting display device does not require a separate light source, unlike a thin film transistor-liquid crystal display (TFT-LCD), and thus has an advantage of reducing the volume and weight of the display device. In addition, since the organic light emitting display device has characteristics such as low power, high brightness, high reaction speed, and low weight, the organic light emitting display device is variously applied to a mobile communication terminal, car navigation, or personal digital assistance. have.

Such an organic light emitting display device includes a cathode electrode for largely electron injection, an anode electrode for injecting holes, and an organic light emitting layer interposed between the cathode electrode and the anode electrode.

The organic light emitting display device injects electrons and holes from the cathode and anode electrodes into the light emitting layer to emit light of the organic light emitting layer, and the light emitted from the organic light emitting layer is reflected between the cathode and the anode electrode. When the equation is satisfied, the color is emitted to the outside to implement the color of the corresponding color filter.

(expression)

Here, L means the distance between the anode electrode and the cathode electrode, that is, the optical thickness, λ represents the peak spectrum, Φ represents the phase shift (phase shift).

According to the above equation, it can be seen that the wavelength λ of light is closely related to the optical thickness (L). Therefore, in order to express a desired color, even if the optical thickness is different for each color of the organic light emitting layer, uniform image quality may be obtained.

That is, the organic light emitting display device also displays a screen in R (red), G (green), and B (blue) colors and a combination thereof similar to a general display device. As the R, G, B color is known, R color has a wavelength of 620 to 700nm, G color has a wavelength of 500 to 570nm, B color has a wavelength of 450 to 500nm. As the wavelength of each color is different in this way, it is possible to obtain a uniform picture quality by adjusting the optical thickness of the color based on the above equation.

Thus, in the related art, in order to control the optical thickness for each color, the organic light emitting display device has adjusted the thickness of the anode electrode for each color.

That is, as shown in FIG. 1, a plurality of anode electrodes 20a, 20b, and 20c are formed on the substrate 11 to be arranged at a predetermined interval in one direction. The anode electrodes 20a, 20b, and 20c are composed of a laminated film of the metal film 15 and the transparent conductive layers 18a, 18b, and 18c. In order to form different optical thicknesses to be formed later, the transparent conductive layer is formed. The thicknesses of 18a, 18b, and 18c are formed differently for each color.

For example, the thickness of the transparent conductive layer 18a is relatively thin so that the anode electrode 20a on which the R light emitting layer having the longest wavelength is to be formed has a relatively large thickness. On the other hand, the anode electrode 20c on which the B light emitting layer having the shortest wavelength is to be formed has a relatively thick thickness of the transparent conductive layer 18c so that the B light emitting layer can have a relatively small thickness. The transparent conductive layer 18b of the anode electrode 20b on which the G light emitting layer having the intermediate wavelength is to be formed is thicker than the transparent conductive layer 18a on which the R light emitting layer is to be formed, and the thickness of the transparent conductive layer 18c on which the B light emitting layer is to be formed. Rather than thin.

Since the anode electrodes 20a, 20b, and 20c have different thicknesses of the transparent conductive layers 18a, 18b, and 18c for each pixel, the photolithography process must be performed for each pixel individually. That is, the process of forming the anode electrode 20a in the R pixel (region where the R light emitting layer is to be formed), the process of forming the anode electrode 20b in the G pixel, and the process of forming the anode electrode 20c in the B pixel, respectively Proceeding separately, anode electrodes 20a, 20b, and 20c having transparent conductive layers 18a, 18b, and 18c of different thicknesses are formed.

Next, an insulating film is formed over the substrate 11 on which the anode electrodes 20a, 20b, and 20c are formed, and then openings are formed to expose the anode electrodes 20a, 20b, and 20c, respectively, and then a known manner in the openings. Thus, the R light emitting layer R, the G light emitting layer G, and the B light emitting layer G are formed. Since the thickness of the anode electrodes 20a, 20b, and 20c is different for each light emitting layer, the R light emitting layer R is formed thicker than the G and B light emitting layers G and B, and the G light emitting layer G is a B light emitting layer. It is formed thicker than (B). A plurality of cathode electrodes 50 are formed on the insulating layer 30 on which the R, G, and B light emitting layers R, G, and B are formed so as to cross the anode electrodes 20a, 20b, and 20c.

However, in the conventional organic light emitting display device, in order to form R, G, and B light emitting layers having different thicknesses, as the anode electrode is formed for each pixel, not only the number of masks increases but also the photolithography process that is performed for a long time. Since a number of times have to be progressed, there is a problem that the manufacturing time as well as the process time is increased.

Accordingly, an object of the present invention is to provide a method for manufacturing an organic light emitting display device, which is designed to solve the conventional problems as described above, which can reduce manufacturing costs and processing time by reducing the number of mask processes. have.

Another object of the present invention is to provide an organic light emitting display device obtained by the above-described manufacturing method.

In order to achieve the above object, the organic light emitting display device according to an aspect of the present invention includes a transparent insulating substrate in which R, G, and B pixels are limited. An anode electrode extending in one direction for each of R, G, and B pixels is formed on the insulating substrate, and an insulating film having an opening exposing the anode electrode of each pixel is covered on the anode electrode. An organic light emitting layer for emitting a color of the pixel is coated in the opening, and a cathode electrode is formed on the organic light emitting layer so as to intersect the anode electrode. In this case, the anode electrode includes a metal pattern, a transparent conductive layer formed to cover the top and sidewalls of the metal pattern and a buffer pattern interposed between the metal pattern and the transparent conductive layer, wherein the thickness of the buffer pattern is R, It is different for each G and B pixel.

Preferably, the thickness of the buffer pattern is sequentially increased in the order of R, G, and B pixels.

In addition, a method of manufacturing an organic light emitting display device according to another aspect of the present invention is as follows. First, a metal film is formed on an insulating substrate in which R, G, and B pixels are divided, and then a buffer layer is formed on the metal film. Thereafter, the buffer layer is etched using a halftone mask to form buffer patterns having different thicknesses for each R, G, and B pixel. Next, the metal layer is etched in the form of the buffer pattern to form a metal pattern. Subsequently, a transparent conductive layer is formed on the substrate on which the buffer pattern and the metal pattern are formed, and then the transparent conductive layer is etched so as to be separated for each pixel while covering the buffer pattern and the metal pattern to form an anode. After forming an insulating film including an opening exposing the upper portion of the anode electrode, R, G, B organic light emitting layer is selectively formed in the opening, and a cathode electrode is formed on the insulating film and the organic light emitting layer.

(Example)

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

2 to 4 are cross-sectional views of respective processes for explaining a method of manufacturing an organic light emitting display device according to an exemplary embodiment of the present invention.

First, referring to FIG. 2, a metal film 115 serving as a reflective layer is deposited on the substrate 110. As the substrate 110, a transparent insulating substrate, for example, a glass substrate, may be used. The thickness control buffer layer 120 is formed on the metal film 115. In the present embodiment, the thickness control buffer layer 120 may be a transparent dielectric layer, such as a silicon oxide film. The buffer layer 120 is formed in consideration of the thickness of the light emitting layer having the shortest wavelength, for example, the B light emitting layer.

Referring to FIG. 3, a photoresist film (not shown) is applied on the buffer layer 120. Next, a mask for defining a photoresist pattern having multiple thicknesses, for example, a halftone mask 200 is disposed on the substrate 110. The halftone mask 200 is a mask having patterns having different degrees of light transmission, and includes, for example, a pattern for blocking 100% of an exposure amount and a pattern for transmitting a part of the exposure amount. Then, the thickness of the photoresist pattern is differently formed by the degree of transmission of the exposure dose, and as a result, the thickness of the layer to be etched by the photoresist pattern is also different.

In the present exemplary embodiment, the halftone mask 200 may include a light shielding pattern 210 that blocks 100% of an exposure amount, a first semi-transmissive pattern 220 that blocks 40 to 60% of an exposure amount, and a second to block 10-30% of an exposure amount. Translucent pattern 230. In addition, the halftone mask 200 may include the light blocking pattern 210 in the anode electrode predetermined region of the B pixel, the first semitransmissive pattern 220 in the anode electrode predetermined region of the G pixel, and the second semitransmissive pattern. The 230 may be aligned to correspond to the anode electrode predetermined region of the R pixel, respectively.

When the photoresist film (not shown) is exposed and developed using the halftone mask 200 as described above, the first photoresist pattern having a normal thickness without exposure to a region corresponding to the light blocking pattern 210 is exposed. (Not shown) is formed, and a partial exposure is performed in a region corresponding to the first transflective pattern 220 to form a second photoresist pattern (not shown) having a thickness smaller than that of the first photoresist pattern. In addition, a portion of the region corresponding to the second transflective pattern 230 may be partially exposed to form a third photoresist pattern (not shown) having a thickness thinner than that of the second photoresist pattern.

Thereafter, the exposed buffer layer 120 is patterned by first to third photoresist patterns (not shown) having different thicknesses to form buffer patterns 120a, 120b and 120c having different thicknesses. That is, by the halftone mask 200, the buffer pattern 120a formed in the B pixel is thicker than the buffer patterns 120b and 120c formed in the G and R pixels, and the buffer pattern formed in the G pixel. 120b is formed thicker than the buffer pattern 120c formed in the R pixel. The photoresist pattern is then removed in a known manner. In this case, the buffer patterns 120a, 120b, and 120c may have a tapered etching process when the buffer layer is etched so that sidewalls thereof may have a taper shape.

4, the metal layer 115 is etched using the buffer patterns 120a, 120b and 120c as a mask to form the metal pattern 116. As the sidewalls of the buffer patterns 120a, 120b and 120c have a tapered shape, the sidewalls of the metal pattern 116 formed using the buffer patterns 120a, 120b and 120c as masks also have a tapered shape. . In addition, as the sidewall of the metal pattern 116 has a tapered shape, the line width of the metal pattern 116 is larger than the buffer patterns 120a, 120b, and 120c.

Next, a transparent conductive layer 122, for example, ITO, IZO, ZnO, or In ₂ O _3, is formed on the substrate 110. Subsequently, the transparent conductive layer 122 is etched to encapsulate the laminated structure including the metal pattern 116 and the buffer patterns 120a, 120b, or 120c so that the transparent conductive layer 122 may be separated for each pixel. And 125b and 125c.

The anode electrodes 125a, 125b and 125c thus formed have different thicknesses (height) of the buffer patterns 120a, 120b and 120c interposed between the transparent conductive layer 122 and the metal pattern 116 for each pixel. The height of the opening in which the organic emission layer is to be formed may vary for each pixel. In addition, as the metal pattern 116 has a wider line width than the buffer patterns 120a, 120b, and 120c and is tapered, the metal pattern 116 may be easily in contact with the transparent conductive layer 122.

An insulating layer 130 is formed on the substrate 110 on which the anode electrodes 125a, 125b, and 125c are formed. Thereafter, the insulating layer 130 is etched to expose each of the anode electrodes 125a, 125b and 125c to form openings 130R, 130G and 130B in which the organic light emitting layer is to be formed. In this case, the openings 130R, 130G, and 130B have different depths d1, d2, and d3, respectively, due to the buffer patterns 120a, 120b, and 120c interposed in the anode electrodes 125a, 125b, and 125c. That is, the opening 130R of the R pixel having the relatively thin thickness buffer pattern 120c is formed to have the deepest first depth d1, and the G having the medium thickness buffer pattern 120b is provided. The opening 130G of the pixel is formed to have a second depth d2 which is a medium depth, and the opening 130B of the B pixel having the buffer pattern 120a having the thickest thickness has the shallowest third depth d3. It is formed to have.

Next, the organic light emitting layers 135R, 135G, and 135B are selectively formed for each of the openings 130R, 130G, and 130B. For example, the R organic emission layer 135R is selectively formed in the opening 130R of the R pixel using a fine metal mask (not shown). Subsequently, the G organic emission layer 135G is selectively formed in the opening 130G of the G pixel by using a fine metal mask (not shown), and the B organic emission layer 135B is similarly applied to the opening 130G of the B pixel. ). As a result, the R organic light emitting layer 135R is formed to have a large thickness by the anode electrode 125c formed at a relatively low thickness, and the G and B organic light emitting layers 135G and 135B are formed as the anode electrode 125c of the R pixel. The anode electrodes 125b and 125c are formed to have a smaller thickness in sequence.

Thereafter, a plurality of cathode electrodes 140 are formed on the insulating layer 130 on which the organic light emitting layers 135R, 135G, and 135B are formed so as to cross the anode electrodes 125a, 125b, and 125c.

In the present embodiment, although the thin film buffer pattern 120c is formed on the anode electrode 125c of the R pixel, the buffer pattern 120c may not be formed on the R pixel.

In addition, although a transparent dielectric layer, such as a silicon oxide film, is used as the buffer layer in the present embodiment, the present invention is not limited thereto and may include any conductive layer, as long as the film has a good adhesive property between the metal pattern and the transparent conductive layer. .

In addition, although the glass substrate is described as an example in the present embodiment, in addition, polyethersulphone (PES), polyacrylate (PAR, polyacrylate), polyetherimide (PEI), polyethylene naphthalate (PEN, polyethyelenen napthalate), polyethylene terephthalate (PET, polyethyeleneterepthalate), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose triacetate ( TAC), cellulose acetate propionate (CAP), and a plastic substrate selected from the group consisting of:

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above embodiments, and various modifications may be made by those skilled in the art within the scope of the technical idea of the present invention. .

As described in detail above, a buffer layer having a different thickness is interposed between the metal pattern constituting the anode electrode and the transparent conductive layer.

In this case, since the buffer layers having different thicknesses are defined by one halftone mask, only two masks for defining the halftone mask and the transparent conductive layer are required to form an anode electrode.

Accordingly, in order to form the anode electrodes for each pixel, at least three masks (R, G, B pixels) were required, but according to the present embodiment, the anode electrodes can be formed using only two masks. And photolithography processes can be reduced.

Claims (9)

An insulating substrate on which R, G, and B pixels are defined; An anode arranged on the insulating substrate in one direction and formed for each of the R, G, and B pixels; An insulating film having openings exposing the respective anode electrodes; R, G and B organic light emitting layers respectively formed in the openings of the pixel; And It is disposed on the R, G, B organic light emitting layer, and includes a cathode electrode extending in a direction crossing the anode electrode, The anode electrode includes a metal pattern, a transparent conductive layer formed on upper and sidewalls of the metal pattern, and a buffer pattern interposed between the metal pattern and the transparent conductive layer, wherein the thickness of the buffer pattern is R, G, An organic light emitting display device, characterized in that different for each B pixel. The method of claim 1, The thickness of the buffer pattern is an organic light emitting display device, characterized in that sequentially increasing in the order of R, G, B pixels. The method of claim 2, And the buffer pattern is a transparent dielectric layer. The method of claim 1, The line width of the metal pattern is larger than the line width of the buffer pattern. The method of claim 1, The sidewalls of the metal pattern and the buffer pattern have a tapered shape. Forming a metal film on a substrate in which R, G, and B pixel areas are divided; Forming a buffer layer on the metal layer; Photolithography and etching the buffer layer using a halftone mask to form buffer patterns having different thicknesses; Etching the metal layer in the form of the buffer pattern to form a metal pattern; Forming a transparent conductive layer on the substrate on which the buffer pattern and the metal pattern are formed; Forming an anode electrode by etching the transparent conductive layer covering the buffer pattern and the metal pattern to be separated for each pixel; Forming an insulating film including an opening exposing an upper portion of the anode electrode; Selectively forming an R, G, B organic light emitting layer in the opening; And Forming a cathode on the insulating layer and the organic light emitting layer; Method of manufacturing an organic light emitting display device comprising a. The method of claim 6, Forming the buffer pattern, Applying a photoresist film on the buffer layer; Aligning a halftone mask having a light shielding pattern for shielding the exposure amount by 100% on the substrate on which the photoresist film is formed and a first and second transflective pattern for shielding (transmitting) only a portion of the exposure amount; Exposing and developing the photoresist film using the halftone mask to form a photoresist pattern having a different thickness; Etching the buffer layer in the form of the photoresist pattern to form a buffer pattern; And Removing the photoresist pattern; Method of manufacturing an organic light emitting display device comprising a. The method of claim 7, wherein The buffer layer is a method of manufacturing an organic light emitting display device, characterized in that the etching by a tapered etching method. The method of claim 8, And etching the metal layer using the buffer pattern as a mask in the etching of the metal pattern.

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