KR100490536B1 - Top emission type organic electro luminescence display device - Google Patents

Abstract

According to the present invention, according to the present invention, an organic light emitting display device includes a substrate, a buffer layer formed on the substrate, a thin film transistor layer formed on the buffer layer, one or more thin film transistor insulating layers provided on the thin film transistor layer, and the thin film. A first internal insulating layer filling the transistor layer, an enowood electrode layer formed in a predetermined pattern on an upper surface of the first internal insulating layer, and having a potential applied by a thin film transistor, and the enowood electrode layer exposed; A second internal insulating layer having an opening, an organic film formed on an upper surface of the anode wood layer, and a cathode layer formed in a predetermined pattern on an upper surface of the organic film and the second internal insulating layer, wherein the buffer layer includes: At least one of the first and second internal insulating layers is formed of a black layer to absorb external light

Description

Top emission type organic electroluminescence display device

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device having an improved external light reflection prevention structure.

Electroluminescent display devices are attracting attention as next-generation display devices as active light emitting display devices because they have a wide viewing angle, excellent contrast, and fast response speed. The organic light emitting display is classified into an inorganic light emitting display and an organic light emitting display according to a material forming the light emitting layer.

The inorganic electroluminescent display was originally commercialized as a green light emitting display, but similar to a plasma display, it is an AC bias drive and requires several hundred volts to drive. In addition, since the material for emitting light is an inorganic material, it is difficult to control the light emission wavelength due to the molecular design and colorization of the image is difficult.

 In addition, the organic light emitting display is a self-luminous display that electrically excites fluorescent organic compounds to emit light, which can be driven at a low voltage, is easy to thin, and is pointed out as a problem in liquid crystal display devices such as wide viewing angle and fast response speed. It is attracting attention as the next generation display that can solve the shortcomings.

The organic light emitting display device was developed in a stack type by Eastman Kodak, and commercialized as a green display having an improved lifetime by Pioneer.

On the other hand, the organic electroluminescent display device has been actively researched as a color displayer having various characteristics of molecular structure, which is an advantage of organic materials, and having excellent characteristics such as DC low voltage driving, thinness, and self-luminous property.

FIG. 1 shows an example of an AM type organic electroluminescent display.

Referring to the drawings, the substrate 10, the buffer layer 11 formed on the upper surface of the substrate 10 and the p-type or n-type semiconductor layer 21 formed in a predetermined pattern on the upper surface of the buffer layer 11 and A gate insulating layer 22 formed on the semiconductor layer 21, a gate electrode layer 23 corresponding to the semiconductor layer 21 on the upper surface of the gate insulating layer 22, and an intermediate insulating layer filling the gate insulating layer 22. 24 and connected to both sides of the semiconductor layer 21 through contact holes 25a and 26a formed in the intermediate insulating film 25 and the gate insulating layer 22, respectively, and formed on the intermediate insulating film 24. The drain electrode 25 includes a thin film transistor including a source electrode 26.

The first electrode 41 connected to the source electrode 26 and formed on the upper surface of the intermediate insulating film 23, and the second electrode opposing the first electrode 41 and embedded in the intermediate insulating film 23 ( And a capacitor 40 made of 42. An insulating protective film 28 and a planarization film 29 having openings 29a formed in the pixel formation region are formed on the upper surface of the intermediate insulating film 23. An electrode 31 electrically connected to the drain electrode 25 is formed on a bottom of the opening of the planarization layer 29, and an organic layer 32 is stacked on the electrode 31. The cathode electrodes 33 are formed on the planarization layer 29.

The organic light emitting display device drives a thin film transistor by applying a plurality of voltage applying lines made of metal, that is, a gate line used to select a pixel, a data line applying a data signal, and applying the same common voltage to all pixels. A power supply line for supplying the reference voltage required for the installation is provided.

The AM active matrix organic light emitting device configured as described above has a wiring voltage supply line for supplying power to a thin film transistor, which is a switching element, that is, a gate line, a data line, and a power supply line are made of metal. Since the external light is reflected by these, the contrast is greatly reduced.

Such reflection of external light degrades the readability of the image. In particular, in the outdoor exposed to sunlight, relative luminance and contrast are rapidly reduced by the external light reflection.

On the other hand, the conventional organic light emitting display device is attached to the surface by a polarizing film (polarizing film) (polarizing film) to reduce the decrease in the brightness of the image due to external light reflection. However, the use of the polarizing plate as described above may cause a substantial reduction in luminance since some of the light generated from the organic layered structure is blocked.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and to prevent the external light reflection to improve the brightness and contrast, and to provide an organic electroluminescent display device having a relatively simple structure by eliminating the use of a polarizing plate. There is this.

In order to achieve the above object, an organic electroluminescent display device of the present invention includes a substrate, a buffer layer formed on the substrate, a thin film transistor layer formed on the buffer layer, an intermediate insulating layer filling the thin film transistor layer, and an upper surface of the intermediate insulating layer. An electrode layer formed in a predetermined pattern on the electrode layer to which a potential is selectively applied by a thin film transistor, an insulating protective film layer having an opening formed to expose the electrode layer, an organic electroluminescent part formed by laminating an organic film on an upper surface of the electrode layer, and It includes a cathode layer formed in a predetermined pattern on the upper surface of the organic electroluminescent portion and the protective film,

At least one of the insulating layers is characterized in that made of a black layer to absorb external light.

In the present invention, the buffer layer formed on the upper surface of the substrate is a black layer or the protective film is a black layer.

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

2 and 3 illustrate an example of an AMMO organic light emitting display (AMOLCD).

Referring to the drawings, a substrate 50, a switching element forming portion formed of a thin film transistor on the upper surface of the substrate 50, a pixel forming portion and a wiring layer forming portion for applying a voltage to drive the thin film transistor The thin film transistor includes one or more thin film transistor insulating layers such as a gate insulating layer.

A buffer layer 51 is formed on the upper surface of the substrate 50, and the p-type or n-type semiconductor layer 52 is formed on the upper surface of the buffer layer 51 in a predetermined pattern. A gate insulating layer 53 filling the semiconductor layer 52 is formed in the buffer layer 51 on which the semiconductor layer 52 is formed, and a gate electrode is formed on an upper surface of the gate insulating layer 53 corresponding to the semiconductor layer 52. 54 and a first internal insulating layer 55 serving as an intermediate layer in which the gate electrode 54 is embedded are formed.

 The first internal insulating layer 55 is connected to both sides of the semiconductor layer 52 through contact holes 26a and 27a formed in the first internal insulating layer 55 and the gate insulating layer 53, respectively. The drain electrode 56 and the source electrode 57 are formed on the upper surface of the ().

 A first internal insulating layer 55 as a passivation layer is formed on the drain electrode 56, the source electrode 57 and the first internal insulating layer as an intermediate layer. On the upper surface of the first internal insulating layer 55 as the passivation layer, a second internal insulating layer 58 having an opening 58a for forming a pixel region is formed. The second internal insulating layer may be separated into two internal insulating layers to insulate the drain electrode 56 and the source electrode from the electrode 61 described later.

An anode electrode 61 electrically connected to the drain electrode 56 is formed on a bottom of the opening 58a, and an organic layer 62 is stacked on the anode wood 61. The cathode layer 63 having a predetermined pattern is formed on the upper surfaces of the 62 and the second internal insulating layer. The cathode layer 63 may include ITO, which is a transparent conductive material.

Meanwhile, in the organic light emitting display device, at least one of the buffer layer 51, the gate insulating layer 53, and the first and second internal insulating layers 55 and 58 absorbs external light and reflects external light. It is made of a black layer to prevent it.

Preferably, as shown in FIGS. 3 and 4, the second internal electrode layer is formed of a black layer, in which a gate line used to select a pixel and a data line to which a data signal is applied are covered.

In another embodiment of the present invention, the enwood electrode 61 may be formed of a conductive black layer to absorb external light. In this case, at least one of the buffer layer 51, the gate insulating layer 53, and the first and second internal insulating layers 55 and 58 may be a black layer to absorb external light and prevent reflection of external light. It is desirable to maximize the external light reflection efficiency by forming.

In the organic light emitting display device configured as described above, when power is applied to the selected thin film transistor and the cathode layer, electrons and holes are recombined in the emission layer of the organic layer to generate excitons, and the excitons are excited in the excited state. As the state is changed, an image is formed by the fluorescent molecules of the light emitting layer emitting light.

In the organic light emitting display device driven as described above, at least one of the buffer layer 51, the gate insulating layer 53, and the first and second internal insulating layers 55 and 58 may absorb external light incident from the outside. Since it is formed of a black layer so as to reduce reflection of incident external light, it is possible to prevent the luminance and contrast of the image from being lowered.

The organic light emitting display device of the present invention made as described above can improve the contrast and brightness of an image implemented by greatly reducing the reflectance of external light, and in particular, it is possible to remove the polarizing plate to block external light, thereby improving productivity. We can plan.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those of ordinary skill in the art that various modifications and variations can be made therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a cross-sectional view of a conventional organic light emitting display device;

2 is a cross-sectional view of an organic light emitting display device according to the present invention;

3 is a plan view of the organic light emitting display device illustrated in FIG. 2;

Claims (2)

A substrate, a buffer layer formed on the substrate, a thin film transistor layer formed on the buffer layer, at least one thin film transistor insulating layer provided on the thin film transistor layer, a first internal insulating layer filling the thin film transistor layer, and the first interior. On the top surface of the insulating layer is formed in a predetermined pattern and the potential of the anode is selectively applied by the thin film transistor, the second inner insulating layer having an opening so as to expose the enowood electrode layer, and the top surface of the enowood electrode layer And a cathode layer formed on a top surface of the organic layer and the second inner insulating layer in a predetermined pattern and including a transparent conductive material. And the first inner insulating layer is formed of a black layer capable of absorbing external light. A substrate, a buffer layer formed on the substrate, a thin film transistor layer formed on the buffer layer, at least one thin film transistor insulating layer provided on the thin film transistor layer, a first internal insulating layer filling the thin film transistor layer, and the first interior. On the top surface of the insulating layer is formed in a predetermined pattern and the potential of the anode is selectively applied by the thin film transistor, the second inner insulating layer having an opening so as to expose the enowood electrode layer, and the top surface of the enowood electrode layer And a cathode layer formed on a top surface of the organic layer and the second inner insulating layer in a predetermined pattern and including a transparent conductive material. And the second inner insulating layer is formed of a black layer capable of absorbing external light.