KR100491822B1 - liquid crystal display device and manufacturing method the same - Google Patents

Abstract

The present invention is a first insulating substrate; Gate lines and data lines arranged vertically and horizontally on the first insulating substrate to define pixels; A thin film transistor formed in each pixel to be connected to the gate line and the data line; An organic electroluminescent layer disposed on the thin film transistor and having a first hole penetrating therein to expose a portion of the drain electrode of the thin film transistor; A liquid crystal display comprising a first substrate positioned above the organic light emitting layer, connected to the thin film transistor drain electrode through the first hole, and including a pixel electrode corresponding to each pixel, and a method of manufacturing the same. .

Description

Liquid crystal display device and liquid crystal display device and manufacturing method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having a light source mounted thereon using an electro electroluminescence phenomenon and a method of manufacturing the same.

BACKGROUND ART In general, a liquid crystal display includes a liquid crystal panel for adjusting light transmittance for displaying an image displayed to a user, and a back light unit for supplying light to the liquid crystal panel.

The liquid crystal panel has a structure in which two substrates each having an electric field generating electrode formed on one surface thereof are arranged to face each other, and then the liquid crystal layer is interposed therebetween.

Liquid crystals have a thin and long molecular structure, optical anisotropy having an orientation in the array, and polarization properties in which the arrangement direction changes when an electric field is artificially applied. By controlling the voltage difference between the opposing field generating electrodes, the liquid crystal molecules can be arbitrarily controlled, and thus the light transmittance can be controlled.

However, since there is no light emitting element in the liquid crystal panel, a backlight unit including a plurality of light sources is provided to supply light to the liquid crystal panel, so that an image identifiable by the user is displayed.

The backlight unit includes a plurality of light sources that emit light, and an optical member that reflects and diffuses the light generated therefrom to the front of the liquid crystal panel. Hereinafter referred to simply as backlight.

On the other hand, in a general liquid crystal panel, a plurality of pixels are formed as a basic unit of image expression. Currently, an active matrix method that independently controls these pixels by using switching elements is widely used. Hereinafter, a general active matrix liquid crystal display device will be described with reference to the drawings.

1 is an exploded perspective view of a general liquid crystal display device, including a liquid crystal panel 5 including first and second substrates 10 and 20 facing each other with a liquid crystal layer 30 interposed therebetween, and the liquid crystal panel 5. It includes a backlight 50 for irradiating light from the back toward the front.

In the liquid crystal panel 5, the first substrate 10 includes a plurality of transparent first insulating substrates 11, such as glass, and vertically and horizontally arranged on one surface thereof to define the pixels P in a matrix form. A pixel electrode corresponding to the pixel P in a state of being connected to the thin film transistor T and each thin film transistor T as a switching element formed at the gate line 13 and the data line 15 and the intersection thereof. (17).

The pixel electrode 17 corresponds to one field generating electrode that applies a voltage to the liquid crystal layer 30.

The second substrate 20 includes a second insulating substrate 21, a black matrix 23 and a color filter layer 25 sequentially formed on one surface thereof, and a common electrode 27.

In this case, the black matrix 23 covers the image area, that is, the pixel electrode 17 by covering non-image areas such as the gate line 13, the data line 15, and the thin film transistor T of the first substrate 10. Expose the parts to the outside.

The color filter layer 25 is a repetitive arrangement of red, green, and blue color filters 25a, 25b, 25c that reflect light of a specific wavelength band in a state corresponding to each pixel P of the first substrate 10. Is done.

The common electrode 27 is made of a transparent conductive metal, and serves as another field generating electrode for applying a voltage to the liquid crystal layer 30 together with the pixel electrode 17 described above.

The first substrate 10 and the second substrate 20 face each other so that the pixel electrode 17 and the common electrode 27 face each other with the liquid crystal layer 30 interposed therebetween. 20, a seal pattern is formed at the edge to prevent cell gap maintenance and liquid crystal leakage between the substrates. First and second alignment films for determining the initial alignment direction of the liquid crystals are interposed between the substrates 10 and 20 and the liquid crystal layer 30, respectively.

In the liquid crystal panel 5 having the above structure, a common voltage Vcom having a fixed potential is applied to the common electrode 27, and an image voltage is applied to the pixel electrode 17. Therefore, the transmittance may be changed by rotating the liquid crystal molecules of the liquid crystal layer 30 through the voltage difference therebetween. In addition, the light emitted from the backlight 50 provided on the rear surface of the liquid crystal panel 5 may control transmittance according to the liquid crystal molecules array direction, thereby displaying images of various luminance.

On the other hand, the general liquid crystal panel 5 according to the above structure has an aperture ratio of less than 70%, resulting in a large amount of light loss. Therefore, the backlight 50 emits light of high luminance, and particularly, since the backlight 50 is always kept on, there is a large waste of power.

In addition, as the display device becomes thinner and smaller in size, the backlight 50 provided separately from the liquid crystal panel 5 does not satisfy the above requirements.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a liquid crystal display device capable of displaying an image of sufficient luminance and simultaneously designing a thin film.

The present invention to achieve the above object, the first insulating substrate; Gate lines and data lines arranged vertically and horizontally on the first insulating substrate to define pixels; A thin film transistor formed in each pixel to be connected to the gate line and the data line; An organic electroluminescent layer disposed on the thin film transistor and having a first hole penetrating therein to expose a portion of the drain electrode of the thin film transistor; A liquid crystal display device comprising a first substrate positioned on the organic electroluminescent layer, connected to the thin film transistor drain electrode through the first hole, and including a pixel electrode corresponding to each pixel.

A first insulating film interposed between the thin film transistor and the organic electroluminescent layer and having a second hole communicated with the first hole; And a second insulating layer interposed between the organic electroluminescent layer and the pixel electrode and having a third hole communicating with the first and second holes, wherein the pixel electrode is disposed through the first to third holes. The thin film transistor is connected to the drain electrode.

The present invention also provides a liquid crystal display device comprising first and second substrates facing each other with a liquid crystal layer interposed therebetween, wherein the first substrate is arranged horizontally and horizontally on a first insulating substrate and the first insulating substrate. A gate line and a data line defining a; A thin film transistor formed in each pixel to be connected to the gate line and the data line; An organic electroluminescent layer disposed on the thin film transistor and having a first hole penetrating therein to expose a portion of the drain electrode of the thin film transistor; An upper portion of the organic electroluminescent layer, connected to the thin film transistor drain electrode through the first hole, and including a pixel electrode corresponding to each pixel, wherein the second substrate is disposed on one surface of the organic substrate; Provided are a liquid crystal display including a black matrix and a color filter layer sequentially formed and a common electrode.

Meanwhile, the present invention provides an insulating substrate; Depositing a first metal thin film on an insulating substrate, and then forming a first metal pattern including a gate line and a gate electrode by a first mask process; Forming a first insulating film on the first metal pattern; Forming an amorphous silicon layer on the first insulating film, and doping an impurity on the amorphous silicon to form a shallow impurity amorphous silicon layer; Patterning the amorphous silicon layer and the impurity amorphous silicon layer by a second mask process to form an island-like semiconductor layer covering the gate electrode; After depositing a second metal thin film on the semiconductor layer, a second metal including a source and drain electrodes spaced apart from each other in an overlapping state with the gate electrode by a third mask process, and a data line connected to the source electrode Forming a thin film pattern; Removing the impurity amorphous silicon layer exposed between the spaced source and drain electrodes; Forming a passivation layer on the source and drain electrodes; Depositing a third metal thin film on the passivation layer, and then forming a third metal thin film pattern through which a first hole through which the passivation layer corresponding to the drain electrode is exposed is formed by a fourth mask process; Forming an organic light emitting layer on the third metal thin film pattern; Depositing a fourth metal thin film on the organic light emitting layer, and then forming a fourth metal thin film pattern through which the third hole communicates with the first hole through the organic light emitting layer through a fifth mask process; Forming a second insulating film on the fourth metal thin film pattern; Patterning the second insulating film to form a contact hole through the protective layer to expose the drain electrode through a sixth mask process; After depositing a fifth metal thin film on the second insulating film, forming a fifth metal thin film pattern connected to the drain electrode by a seventh mask process and corresponding to each pixel. Provide a method.

Hereinafter, the correct embodiment of the present invention will be described.

First, prior to the description, the liquid crystal display device according to the present invention is characterized in that a light source using an organic electroluminescence phenomenon is mounted in the liquid crystal panel, thereby replacing the existing backlight.

First, organic electroluminescence refers to an electroluminescence phenomenon, that is, light emitted when a predetermined electric field is applied to a phosphor, and that the source material that causes excitation of carriers is an organic material.

The light emitting device using the above characteristics has a light emitting principle by recombination of electrons and holes, which is also called an organic light emitting diode (OLED). FIG. 2 is a band diagram for explaining the principle of operation of a general organic electroluminescent device.

A typical organic electroluminescent device includes an anode electrode (1) and a cathode electrode (7), a hole transporting layer (3) located between them, an emission layer (4) and an electron An electron transporting layer (5). At this time, in order to inject holes and electrons more efficiently, a hole injection layer (2) between the anode electrode (1) and the hole transport layer (3), and the electron transport layer (5) and the cathode An electron injection layer 6 may be included between the electrodes 7, respectively.

Thus, holes injected from the anode electrode 1 into the light emitting layer 4 through the hole injection layer 2 and the hole transport layer 3, and the electron injection layer 6 and the electron transport layer 5 from the cathode electrode 7 Electrons injected into the light emitting layer 4 form excitons 8, which emit light corresponding to the energy gap between the holes and the electrons. In this case, the anode electrode 1 is made of a material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) which has a high work function and is transparent. ) Has a low work function and chemically stable materials such as aluminum (Al), calcium (Ca) and aluminum alloys.

Therefore, the present invention uses the above-described organic electroluminescent device as a light source of the liquid crystal display device, in particular, it is characterized in that it is mounted in the liquid crystal panel.

FIG. 3 is an exploded perspective view showing an example of a liquid crystal display according to the present invention, and particularly, when applied to an active matrix method.

This includes the first and second substrates 100 and 200 facing each other with the liquid crystal layer 230 therebetween, and in particular, the organic electroluminescent element layer 130 formed on the first substrate 100.

In this case, the first substrate 100 includes a transparent first insulating substrate 102 such as glass, a plurality of gate lines 112 and data arranged vertically and horizontally on one surface thereof to define the pixel P in a matrix form. A line 120, a thin film transistor T formed at an intersection thereof, and a pixel electrode 134 corresponding to the pixel P in a state of being connected to each thin film transistor T.

In addition, an organic light emitting diode layer 130 is formed on the first substrate 102. In particular, each pixel electrode 134 has a contact hole (not shown) penetrating through the organic electroluminescent diode layer 130. It is connected to the thin film transistor (T) through.

The second substrate 200 includes a second insulating substrate 221, a black matrix 223, a color filter layer 225, and a common electrode 227 that are sequentially formed on one surface thereof.

In this case, the black matrix 223 covers the image area, that is, the pixel electrode 134, by covering non-image areas such as the gate line 112, the data line 120, and the thin film transistor T of the first substrate 100. Expose the parts to the outside. In addition, the color filter layer 225 includes a repetitive arrangement of red, green, and blue color filters 225a, 225b, and 225c that reflect light of a specific wavelength band in a state corresponding to each pixel P of the first substrate 100. . The common electrode 227 is made of a transparent conductive metal.

In addition, the first substrate 100 and the second substrate 200 face each other such that the pixel electrode 134 and the common electrode 227 face each other with the liquid crystal layer 230 interposed therebetween. A seal pattern is formed at the edges of the (100, 200) to maintain a cell gap for liquid crystal injection, to prevent adhesion between the two substrates, and to prevent liquid crystal leakage, and to form both substrates (100, 200) and the liquid crystal layer. First and second alignment layers for determining the initial alignment direction of the liquid crystal are respectively interposed at the boundary of 230.

On the other hand, the second substrate 200 of the liquid crystal display according to the present invention having the above structure is similar to the general case in terms of its configuration. Therefore, the most characteristic feature of the present invention may be the first substrate 100 including the organic electroluminescent layer 130, which will be described below.

4 is a plan view of one pixel P formed on the first substrate 100, and FIG. 5 is a cross-sectional view taken along the line V-V of FIG. 4.

Each of the pixels P is defined by the vertical and horizontal gate lines 112 and the data lines 120, and thin film transistors T are formed at their intersections.

The thin film transistor T includes a gate electrode 112a branched from the gate line 112, a source electrode 120a branched from the data line 120, and a drain electrode 122 connected to the pixel electrode 134. And a semiconductor layer 118, which is a carrier movement path such as a hole or a hole, wherein the semiconductor layer 118 is an active layer 116 of pure amorphous silicon and doped with impurities. And an ohmic contact layer 117 of amorphous silicon.

In this case, an organic electroluminescent device layer 130 is formed on the gate line 112, the data line 120, and the thin film transistor T, and an interlayer insulating layer is formed on the upper portion thereof.

The pixel electrode 134 is connected to the thin film transistor (T) drain electrode through the insulating contact hole 150 penetrating the organic electroluminescent element layer 130 on the interlayer insulating layer.

The organic electroluminescent device layer 130 includes a first electrode 124, an organic light emitting layer 126, and a second electrode 128.

Hereinafter, a liquid crystal display and a method of manufacturing the same according to the present invention will be described in detail with reference to FIGS. 6A to 6G, which show cross-sections cut along the V-V line of FIG. 4 according to a process sequence.

First, as shown in FIG. 6A, the first metal is deposited as a thin film on the transparent first insulating substrate 102, and then patterned to form a gate line 112 and a gate electrode 112a branched therefrom. As the first metal, various conductive metals such as aluminum (Al), aluminum alloy, molybdenum (Mo), tungsten (W), and chromium (Cr) may be used.

The gate insulating film 114 serving as the first insulating film is stacked over the entire gate line 112 and the upper portion of the gate electrode 112a. The gate insulating layer 114 may be one selected from a group of organic insulating materials including silicon nitride (SiN _x ) and silicon oxide (SiO ₂ ).

Subsequently, as shown in FIG. 6B, a pure amorphous silicon layer is stacked on the gate insulating layer and then doped with impurities to form a shallow impurity amorphous silicon layer. Each of the patterns is patterned to cover the gate electrode 112a in an island shape, and to form an active layer 116 made of pure amorphous silicon at the bottom and a shallow impurity silicon film 117a thereon.

Next, a second metal thin film is deposited on top of it and then patterned. As shown in FIG. 6C, the source electrode 120a and the drain electrode 122, and the data line 120 connected to the source electrode 120a are spaced apart from each other to overlap the gate electrode 112a to some extent. Is formed. The ohmic contact layer 117 is formed by removing a portion of the impurity silicon film 117a of FIG. 6B exposed between the source electrode 120a and the drain electrode 122.

In this case, when the second metal thin film is molybdenum, the ohmic contact layers and the source and drain electrodes 120a and 122 may be formed by dry etching. In the case of chromium, the second metal thin film may be patterned first through a wet electrode to source and drain. The electrodes 120a and 122 are formed, successively dry etching, and the impurity silicon film 117a of FIG. 6B is removed therebetween.

Subsequently, as shown in FIG. 6D, one selected from the group of transparent organic insulating materials including benzocyclobutene (BCB) and acrylic resin (resin) on the upper surface of the source and drain electrodes 120a and 122 are formed. Or a selected one of a group of inorganic insulating materials including silicon nitride (SiNx) and ash silicon (SiO ₂ ) is deposited to form a protective film 123 as a second insulating film.

As shown in FIG. 6E, a third metal thin film which is to serve as an electrode of the organic electroluminescent layer (see 130 of FIG. 4) to be described later is deposited on the passivation layer 123, and then patterned to form the drain electrode 114. A first electrode 124 including a first hole through which a portion corresponding to) is formed is formed, and an organic light emitting material is coated on the upper portion to form an organic light emitting layer 126. Subsequently, a fourth metal thin film is deposited on the organic light emitting layer 126 and then patterned to form a second electrode 128 including a second hole through which a portion corresponding to the drain electrode 114 passes.

Therefore, the first hole and the second hole face each other with the organic light emitting layer 126 interposed therebetween, and the first contact hole 140 exposing the protective layer 123 by removing the exposed portion of the organic light emitting layer 126 to connect them. Form.

In this case, when the third metal thin film is applied to the above description, it becomes a cathode electrode of the organic electroluminescent device, and a low work function and chemically stable aluminum (Al), calcium (Ca), or an aluminum alloy may be used. In addition, since the fourth metal thin film becomes the anode electrode according to the foregoing description, a high work function and transparent indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) Use materials such as

As a result, an organic electroluminescent layer 130 including the first electrode 124 of the third metal thin film, the organic light emitting layer 126, and the second electrode 128 of the fourth metal thin film is formed, and the organic electroluminescent layer 130 is formed on the organic electroluminescent layer 130. The first contact hole exposing a portion of the lower passivation layer 123 is penetrated.

6F, an insulating material is coated on the second electrode 128 of the organic electroluminescent layer 130 to form an interlayer insulating film 132, which is a third insulating film. The interlayer insulating film 132 may include one selected from the group of transparent organic insulating materials including benzocyclobutene (BCB) and acryl resin, or silicon nitride (SiN _x ) and silicon oxide (SiO ₂ ). One selected from the group of inorganic insulating materials including may be used.

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6G, an insulating contact hole 150 is formed through the first contact hole 140 to expose the lower drain electrode 114. Therefore, in this case, the thin film transistor T and the organic electroluminescent layer 130 are formed on the first insulating substrate 102, and the insulating contact penetrates from the organic electroluminescent layer 130 to the drain electrode 114. There is a hole 150.

In addition, a transparent material layer, such as indium tin oxide or indium zinc oxide, is formed on the interlayer insulating layer 132 and patterned to implement the pixel electrode 134 as illustrated in FIG. 5. The pixel electrode 134 is connected to the thin film transistor (T) drain electrode 114 through the insulating contact hole 150.

This completes the first substrate as shown in FIG. 4 in the configuration of each pixel. Although not shown, a first alignment film is formed on the first substrate, completed in a separate process, and the second alignment film is formed on the opposite surface. The formed second substrate is bonded to each other, and a liquid crystal display device is completed between the first and second substrates, in particular between the organic electroluminescent layer 130 and the second substrate. It will be apparent to those skilled in the art that a cell polarizer film) is included.

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SUMMARY OF THE INVENTION The present invention has the advantage of providing a liquid crystal display device capable of displaying an image of sufficient brightness by mounting an organic electroluminescent element in a liquid crystal panel and at the same time enabling a thin design.

This makes it possible to realize even more improved picture quality.

1 is a partial perspective view of a general liquid crystal display device

2 is a diagram for explaining the operation principle of the organic electroluminescent device.

3 is a partial perspective view of a liquid crystal display according to the present invention;

4 is a plan view of one pixel of the liquid crystal display according to the present invention.

5 is a cross-sectional view illustrating a cross section taken along the line V-V of FIG. 4.

6A to 6G are cross-sectional views showing the manufacturing process sequence of the cross section taken along the line V-V of FIG.

<Description of the symbols for the main parts of the drawings>

102: first insulating substrate 112a: gate electrode

114: gate insulating film 116: ohmic contact layer

117: active layer 118: semiconductor layer

120: data line 120a: source electrode

114: drain electrode 123: protective film

124: first electrode 126: organic light emitting layer

128: second electrode 132: interlayer insulating film

134: pixel electrode 150: insulated contact hole

Claims (8)

A first insulating substrate; Gate lines and data lines arranged vertically and horizontally on the first insulating substrate to define pixels; A thin film transistor comprising a drain electrode, a gate electrode connected to the gate line, and a source electrode connected to the data line; An organic electroluminescent layer disposed on the thin film transistor and having a first hole penetrating therein to expose a portion of the drain electrode of the thin film transistor; A pixel electrode disposed on the organic electroluminescent layer and electrically connected to the thin film transistor drain electrode through the first hole and corresponding to each pixel; Liquid crystal display substrate comprising a The method according to claim 1, A first insulating layer interposed between the thin film transistor and the organic electroluminescent layer and having a second hole communicated with the first hole; A second insulating layer interposed between the organic electroluminescent layer and the pixel electrode and having a third hole communicating with the first and second holes therethrough; Further, the pixel electrode is a substrate for a liquid crystal display device connected to the thin film transistor drain electrode through the first to third holes The method according to claim 1, The organic electroluminescent layer, A cathode of aluminum (Al), calcium (Ca), or an aluminum alloy at the bottom facing the thin film transistor; An anode electrode of indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) facing the cathode electrode; An organic light emitting layer between the cathode electrode and the anode electrode Liquid crystal display substrate comprising a A liquid crystal display device comprising first and second substrates facing each other with a liquid crystal layer interposed therebetween. The first substrate, A first insulating substrate; Gate lines and data lines arranged vertically and horizontally on the first insulating substrate to define pixels; A thin film transistor comprising a drain electrode, a gate electrode connected to the gate line, and a source electrode connected to the data line; An organic electroluminescent layer disposed on the thin film transistor and having a first hole penetrating through the thin film transistor to expose a portion of the drain electrode; Positioned above the organic electroluminescent layer, connected to the thin film transistor drain electrode through the first hole, and including a pixel electrode corresponding to each pixel; The second substrate, A black matrix and a color filter layer formed on one surface of the first substrate facing the first substrate; Common electrode formed on the black matrix and the color filter layer Liquid crystal display comprising a The method according to claim 4, A first insulating layer interposed between the thin film transistor and the organic electroluminescent layer and having a second hole communicated with the first hole; A second insulating layer interposed between the organic electroluminescent layer and the pixel electrode and having a third hole communicating with the first and second holes therethrough; The liquid crystal display device further includes a pixel electrode connected to the thin film transistor drain electrode through the first to third holes. The method according to claim 4, The organic electroluminescent layer, A cathode of aluminum (Al), calcium (Ca), or an aluminum alloy at the bottom facing the thin film transistor; An anode electrode of indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) facing the cathode electrode; An organic light emitting layer between the cathode electrode and the anode electrode Liquid crystal display comprising a An insulating substrate; Depositing a first metal thin film on an insulating substrate, and then forming a first metal pattern including a gate line and a gate electrode by a first mask process; Forming a first insulating film on the first metal pattern; Forming an amorphous silicon layer on the first insulating film, and doping an impurity on the amorphous silicon to form a shallow impurity amorphous silicon layer; Patterning the amorphous silicon layer and the impurity amorphous silicon layer by a second mask process to form an island-like semiconductor layer covering the gate electrode; After depositing a second metal thin film on the semiconductor layer, a second metal including a source and drain electrodes spaced apart from each other in an overlapping state with the gate electrode by a third mask process, and a data line connected to the source electrode Forming a thin film pattern; Removing the impurity amorphous silicon layer exposed between the spaced source and drain electrodes; Forming a passivation layer on the source and drain electrodes; Depositing a third metal thin film on the passivation layer, and then forming a third metal thin film pattern through which a first hole through which the passivation layer corresponding to the drain electrode is exposed is formed by a fourth mask process; Forming an organic light emitting layer on the third metal thin film pattern; After depositing a fourth metal thin film on the organic light emitting layer, forming a fourth metal thin film pattern through which the second hole communicating with the first hole passes through the organic light emitting layer through a fifth mask process; Forming a second insulating film on the fourth metal thin film pattern; Patterning the second insulating film to form a contact hole through the protective layer to expose the drain electrode through a sixth mask process; Depositing a fifth metal thin film on the second insulating film, and then forming a fifth metal thin film pattern connected to the drain electrode by a seventh mask process and corresponding to each pixel; Substrate manufacturing method for a liquid crystal display device comprising a The method according to claim 7, The first metal thin film is one selected from aluminum (Al), aluminum alloy, molybdenum (Mo), tungsten (W) or chromium (Cr), The second metal thin film is one selected from molybdenum (Mo) or chromium (Cr), The third metal thin film is one selected from aluminum (Al), calcium (Ca), or aluminum alloy, The fourth and fifth metal thin films are one selected from indium tin oxide (ITO) or indium zinc oxide (IZO).