KR20040024964A - Transreflective liquid crystal display device and method for fabricating thereof - Google Patents

Abstract

PURPOSE: A transreflective liquid crystal display and its fabrication method are provided to realize a high quality display by reducing luminance deviation at a light reflection area and a light transmission area. CONSTITUTION: The transreflective liquid crystal display includes the first substrate(100), and the second substrate including the second transparent substrate and a common electrode formed on the second transparent substrate, and a liquid crystal injected between the first substrate and the second substrate. The first substrate includes the first transparent substrate, a power supply unit(120) supplying the first voltage to a plurality of pixel areas formed on the first transparent substrate, a non-transparent organic film having a contact hole and a light transmission area and a pixel electrode(140) including a reflection electrode applying the first voltage to the light reflection area and a transparent electrode applying the first voltage to the light transmission area.

Description

Reflective-transmissive liquid crystal display and its manufacturing method {TRANSREFLECTIVE LIQUID CRYSTAL DISPLAY DEVICE AND METHOD FOR FABRICATING THEREOF}

The present invention relates to a reflection-transmissive liquid crystal display device and a manufacturing method thereof, and more particularly, to a reflection-transmissive liquid crystal display device and a method of manufacturing the same improved display characteristics.

In general, a liquid crystal display device displays information by liquid crystal.

The liquid crystal has electrical characteristics in which the arrangement is changed by the magnetic field and optical characteristics in which the light transmittance is changed by the arrangement.

Liquid crystals do not generate light by themselves. Therefore, light is required to display an image with a liquid crystal display.

Liquid crystal displays are classified into reflective LCDs, transmissive LCDs, and reflective-transmissive LCDs, depending on how light is used.

Reflective liquid crystal display devices are mainly used in small display devices, and transmissive liquid crystal display devices are widely used in small to super large liquid crystal display devices.

Reflective liquid crystal display has the advantages of very low power consumption and the disadvantage that display is not possible in the absence of light, and transmissive liquid crystal display has the advantage of freely performing display anywhere regardless of light and consumes too much power. It has a big disadvantage.

The reflection-transmissive liquid crystal display has the advantages of low power consumption and the advantage of being able to display anywhere.

Structurally, the reflection-transmissive liquid crystal display device is composed of a TFT film (Thin Film Transistor substrate), a color filter substrate (Liquid Crystal).

The TFT substrate again includes a transparent substrate, a thin film transistor, a transparent organic film, a reflective electrode, and a transparent electrode.

The thin film transistor is arranged in a matrix on a transparent substrate. The thin film transistor includes a gate electrode, a source electrode, a drain electrode, and a channel layer.

The transparent organic film is thinly formed over the entire surface of the transparent substrate so that the thin film transistor is covered. In the transparent organic film formed on the transparent substrate, contact holes and convex embossed irregularities are formed together to open the drain electrode of the thin film transistor.

The reflective electrode is formed in the transparent organic film and partly connected to the drain electrode. In this case, one thin film transistor is connected to one reflective electrode. In addition, an opening window is formed in the reflective electrode such that external light is incident through the transparent substrate and the transparent organic film.

The transparent electrode is formed up to the entirety of the reflective electrode and the portion where the opening window is formed. One transparent electrode is connected to one reflective electrode.

The color filter substrate again includes a transparent substrate, a black matrix, a color filter, and a common electrode.

A black matrix having a lattice shape is formed on the transparent substrate. The black matrix serves to cover the thin film transistor formed on the TFT substrate, absorb external light to improve brightness, and cover light between the reflective electrode and the reflective electrode to prevent light leakage.

The color filter is formed for each area partitioned by the black matrix. The color filter is composed of a red color filter that filters the red wavelength, a green color filter that filters the green wavelength, and a blue color filter that filters the blue wavelength.

The common electrode is formed over the entire surface of the transparent substrate to cover the color filter.

The TFT substrate and the color filter substrate are assembled together, and a liquid crystal is injected between the TFT substrate and the color filter substrate to produce a reflection-transmissive liquid crystal display device.

However, such a conventional reflection-transmissive liquid crystal display device has a problem in that when the alignment of the TFT substrate and the color filter substrate is not precisely aligned, the black matrix covers a part of the reflective electrode and the aperture ratio is reduced, thereby degrading display performance. Have

In addition, the conventional reflection-transmissive liquid crystal display device has a problem in that the display luminance at the reflective electrode and the display luminance at the transparent electrode are not the same, and thus display performance is deteriorated.

Accordingly, the present invention has been made in view of such a conventional problem, and a first object of the present invention is to provide a liquid crystal display device capable of realizing a high-quality display by reducing luminance variations in a light reflection region and a light transmission region.

In addition, a second object of the present invention is to provide a method of manufacturing a liquid crystal display device capable of realizing a high quality display by reducing luminance deviation in a light reflection region and a light transmission region.

1 is a conceptual diagram illustrating a reflection-transmissive liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating one of a plurality of pixels formed on a first substrate according to a first embodiment of the present invention.

3 is a cross-sectional view taken along the line A-A of FIG.

4 is a plan view of a second substrate according to a first embodiment of the present invention.

5 is a cross-sectional view taken along the line C-C of FIG.

6 is a cross-sectional view of a liquid crystal display device in which a first substrate and a second substrate are assembled according to the first embodiment of the present invention.

7 is a flowchart illustrating the formation of a thin film transistor on a first substrate of a reflection-transmissive liquid crystal display device according to a second embodiment of the present invention.

8 is a flowchart illustrating an opaque organic film formed on a first transparent substrate according to a second embodiment of the present invention.

9 is a flowchart illustrating an opaque organic film patterned according to a second embodiment of the present invention.

10 is a process diagram illustrating a process of manufacturing a second substrate according to a second embodiment of the present invention.

In order to realize the first object of the present invention, the present invention provides a first transparent substrate, a power supply means for supplying a first voltage to a plurality of pixel regions formed on the first transparent substrate, and a contact formed at an output terminal position of the power supply means. An opaque organic film having light transmitting regions through which light passes through the holes and pixel regions, and light transmitting through the output electrode and the reflecting electrode applying a first voltage to the light reflecting region except the light transmitting region among the pixel regions through the output stage for each pixel region. Between a first substrate including a pixel electrode including a transparent electrode applying a first voltage to a region, a second transparent substrate, a second substrate including a common electrode formed on the second transparent substrate, and a first substrate and a second substrate Provided is a reflection-transmissive liquid crystal display comprising a liquid crystal injected into.

In addition, in order to implement the second object of the present invention, the present invention comprises the steps of forming a power supply means for supplying a first voltage to the plurality of pixel areas formed on the first transparent substrate, contact hole at the output terminal position of the power supply means Forming and forming an opaque organic film having a light transmitting region through which light passes through each pixel region, and forming a reflective electrode in a light reflecting region other than the light transmitting region of the pixel region through an output terminal for each pixel region and a light transmitting region through the output terminal Forming a transparent electrode on the first substrate, forming a common electrode on the second transparent substrate, manufacturing a second substrate, and injecting a liquid crystal between the first substrate and the second substrate; A manufacturing method of a transmissive liquid crystal display device is provided.

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

<Example 1>

1 is a conceptual diagram illustrating a reflection-transmissive liquid crystal display device according to a first embodiment of the present invention.

Referring to FIG. 1, the reflection-transmissive liquid crystal display device 500 includes a first substrate 100, a second substrate 200, and a liquid crystal 300.

FIG. 2 is a block diagram illustrating one of a plurality of pixels formed on a first substrate according to a first embodiment of the present invention. 3 is a cross-sectional view taken along the line A-A of FIG.

2 or 3, the first substrate 100 includes a first transparent substrate 110, a voltage supply device 120, an opaque organic layer 130, and a pixel electrode 140.

The first transparent substrate 110 is preferably a glass substrate excellent in light transmittance. Pixel regions 160 suitable for the desired resolution are formed on the glass substrate. The number of pixel areas 160 is 800 × 600 × 3 when the resolution is 800 × 600.

One voltage supply device 120 is formed for each pixel region 160 formed on the first transparent substrate 110. The voltage supply device 120 is composed of the thin film transistor 127, the gate line 128, and the data line 129.

The thin film transistor 127 includes a gate electrode 121, a channel layer 122, a source electrode 123, and a drain electrode 124. Unexplained reference numeral 125 shown in FIG. 3 is an insulating film insulating the gate electrode 121 and the channel layer 122.

The gate line 128 is connected to the gate electrode 121, and the data line 129 is connected to the source electrode 123. The gate line 128 and the data line 129 are preferably orthogonal in an insulated state.

The opaque organic layer 130 illustrated in FIG. 3 is formed such that the voltage supply device 120 is covered on the first transparent substrate 110. The opaque organic layer 130 is preferably made of a positive photosensitive material which is low in light transmittance, high in light absorption, and is removed by reaction with light. The opaque organic layer 130 absorbs light applied from the outside so that the light is not reflected back to the outside.

The opaque organic layer 130 has a contact hole 131, a light transmitting window 132, and an embossed pattern 133.

The contact hole 131 opens the drain electrode 124 of the thin film transistor 127 disposed under the opaque organic layer 130.

The light transmitting window 132 is formed inside the pixel region 160 illustrated in FIG. 2. The light transmission window 132 allows light to pass through the first transparent substrate 110. The embossing pattern 133 is formed in a hemispherical shape or a random shape having a predetermined rule on the upper surface of the opaque organic film 130. The opaque organic layer 130 also covers the gate line 128 and the data line 129 together.

Referring to FIG. 3, the pixel electrode 140 is composed of a reflective electrode 142 and a transparent electrode 144.

The reflective electrode 142 is formed for each pixel region 160. The reflective electrode 142 is made of aluminum or an aluminum alloy having high light reflectivity, and a part of the reflective electrode 142 is connected to the drain electrode 124 of the thin film transistor 127 exposed by the contact hole 131. . In this case, the light transmitting window 132 formed in the opaque organic layer 130 of the reflective electrode 142 is opened so that light incident through the light transmitting window 132 is not blocked by the reflective electrode 142.

The transparent electrode 144 is formed on the entire area of each pixel region 160. The transparent electrode 144 is made of an indium tin oxide film or an indium zinc oxide film that is conductive and transmits light.

At this time, the positions of the reflective electrode 142 and the transparent electrode 144 may be changed.

4 is a plan view of a second substrate according to a first embodiment of the present invention. 5 is a cross-sectional view taken along the line C-C of FIG.

4 or 5, the second substrate 200 is again composed of a second transparent substrate 210, a color filter 250, and a common electrode 260.

The second transparent substrate 210 is a glass substrate having a high light transmittance. The color filter region is formed on the second transparent substrate 210 to suit the required resolution. The number of color filter regions is the same as the number of pixel regions 160 formed on the first substrate 100 shown in FIG. 1, and the area of the color filter regions is substantially the same as the area of the pixel region 160.

The color filter 250 is formed for each color filter region. The color filter 250 includes a red color filter 220 that emits only light of red wavelength among white light, a green color filter 230 that emits only light of green wavelength among white light, and a blue color filter that emits only light of blue wavelength among white light. It consists of 240. The red color filter 220, the green color filter 230, and the blue color filter 240 are formed one by one for each color filter area according to a predetermined rule.

In this case, the edges of the red color filter 220, the green color filter 230, and the blue color filter 240 may or may not overlap each other.

The common electrode 260 is again formed over the entire surface of the second transparent substrate 210. The common electrode 260 may be an indium tin oxide film or an indium zinc oxide film having excellent conductivity and light transmittance.

The common electrode 260 allows an electric field for controlling the liquid crystal to be formed between the common electrode 260 and the pixel electrode 140.

6 is a cross-sectional view of a liquid crystal display device in which a first substrate and a second substrate are assembled according to the first embodiment of the present invention.

Referring to FIG. 6, the first substrate 100 and the second substrate 200 having such a configuration are assembled to have a specified cell gap.

The liquid crystal 300 is injected or dropped between the assembled first substrate 100 and the second substrate 200.

At this time, the length D1 of the light passing through the transparent window 132 between the transparent electrode 144 and the color filter 250 passes through the color filter 250-reflecting electrode at the reflecting electrode 142. It is approximately equal to the length D2 passed through the (142) -color filter 250. As such, the length of the light passing through the light transmitting window 132 and the length of the light passing through the reflecting electrode 142 become the same, and thus the luminance and the reflecting electrode 142 of the light transmitting window 132. The luminance at becomes almost the same.

In FIG. 6, reference numeral 170 is an alignment layer for orienting liquid crystals.

Second Embodiment

7 is a flowchart illustrating the formation of a thin film transistor on a first substrate of a reflection-transmissive liquid crystal display device according to a second embodiment of the present invention.

Referring to FIG. 7, a gate electrode 121 and a gate line (see FIG. 2) are formed on the first transparent substrate 110 first.

In order to form the gate electrode 121 and the gate line 128, a gate metal made of aluminum or an aluminum alloy is deposited on the first transparent substrate 110 over the entire surface of the first transparent substrate 110. The gate metal deposited on the first transparent substrate 110 will be referred to as a "gate thin film".

In the gate thin film formed on the first transparent substrate 110, the gate electrode 121 and the gate line 128 are simultaneously formed as shown in FIG. 7 through a photolithography process. In this case, one gate electrode 121 is formed for each pixel region (see FIG. 2, 160) set to meet the required resolution.

Next, an insulating film 125 is deposited over the entire surface of the first transparent substrate 110 to cover the gate electrode 121 and the gate line 128. In this case, the insulating film 125 is made of a transparent material with high resistance.

After the insulating film 125 is formed on the first transparent substrate 110, the amorphous silicon layer 122a, which is the channel layer 120, and the n ⁺ amorphous silicon layer 122b are sequentially deposited on the first transparent substrate 110. .

The n ⁺ amorphous silicon layer 122b is patterned to be mutually shorted on the gate electrode 121, and the amorphous silicon layer 122a is patterned so as not to be mutually shorted on the gate electrode 121.

In the state where the channel layer 120 is formed, the source / drain metal thin film is formed on the first transparent substrate 110 again over the entire area, and then patterned to form the source electrode 123 and the drain electrode 124. The data line 129 illustrated in FIG. 2 is formed while the source electrode 123 and the drain electrode 124 are formed.

8 is a flowchart illustrating an opaque organic film formed on a first transparent substrate according to a second embodiment of the present invention. 9 is a flowchart illustrating an opaque organic film patterned according to a second embodiment of the present invention.

8 or 9, an opaque organic layer 135 is formed on the first transparent substrate 110 so that the opaque organic material is coated by a spin coating method to cover all of the thin film transistors 127. do.

In the state where the opaque organic film 135 is formed, the pattern mask 139 is again aligned on the upper surface of the opaque organic film 135.

The pattern mask 139 has three different patterns. The first pattern 136 formed on the pattern mask 139 is a slit pattern as a pattern for forming embossed irregularities on the upper surface of the opaque organic film 135.

The second pattern 137 allows contact holes to be formed in the opaque organic layer 135. A contact hole is formed in the drain electrode 124 of the thin film transistor 127 of the opaque organic layer 135 by the second pattern 137.

The third pattern 138 allows the light transmission window to be formed in the opaque organic layer 135. The light transmission window is formed on the opaque organic layer 135 by the third pattern 138.

The pattern mask 139 on which the patterns 136, 137, and 138 are formed is exposed to light while the pattern mask 139 is aligned with the top surface of the opaque organic layer 135.

As shown in FIG. 9, the opaque organic film 135 is patterned by exposure. Hereinafter, reference numeral 130 will be given to the patterned opaque organic film.

The patterned opaque organic layer 130 is formed with embossed irregularities 133, a contact hole 131, and a light transmitting window 132.

The pixel electrode 140 is formed over the entire area of the opaque organic layer 130 in a state where the embossed unevenness 133, the contact hole 131, and the light transmitting window 132 are formed in the opaque organic layer 130.

The source / drain metal is formed on the opaque organic layer 130 over the entire area, and the source / drain metal is patterned by a photo or etching process to form the reflective electrode 142.

An indium tin oxide film is formed over the entire surface of the opaque organic film 130 in the state where the reflective electrode 142 is formed. Thereafter, the indium tin oxide film is patterned to remain only in the pixel region to form a transparent electrode 144.

10 is a process diagram illustrating a process of manufacturing a second substrate according to a second embodiment of the present invention.

Referring to FIG. 10, first, a color filter 250 is manufactured on the second transparent substrate 210. The color filter 250 is fabricated through the process of depositing the red color filter 220 on the entire surface, patterning the surface, depositing the green color filter 230 on the front surface, patterning, and depositing the blue color filter 240 on the surface. .

In this case, the edges of the color filters 250 may overlap each other or may not overlap each other.

The common electrode 260 is formed on the second transparent substrate 210 while the color filter 250 is formed. The common electrode 260 is made of an indium tin oxide film or an indium zinc oxide film, and is formed over the entire area of the second transparent substrate 210.

Through the above process, the first substrate 100 and the second substrate 200 are assembled to each other while the first substrate 100 and the second substrate 200 are formed.

The liquid crystal 300 is injected into the assembled first substrate 100 and the second substrate 200 to manufacture a liquid crystal display device.

As described in detail above, the organic film for forming the reflective electrode and the transparent electrode in the reflection-transmissive liquid crystal display device uses an opaque organic film having a high light absorption rate and a low light reflectance ratio, The luminance variation of the substrate can be reduced, and the change in aperture ratio due to misalignment of the substrate including the color filter, the thin film transistor, and the substrate on which the pixel electrode is formed can be minimized.

In the detailed description of the present invention described above with reference to a preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge in the scope of the invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (9)

(a) a first transparent substrate, (b) a power supply means for supplying a first voltage to a plurality of pixel regions formed on the first transparent substrate, (c) a contact hole formed at an output end position of the power supply means and the pixel An opaque organic film having a light transmissive region through which light passes through each region, (d) a reflective electrode for applying the first voltage to the light reflecting region other than the light transmissive region through the output terminal per pixel region, and through the output terminal A first substrate including a pixel electrode including a transparent electrode applying the first voltage to the light transmitting region; A second substrate including a second transparent substrate and a common electrode formed on the second transparent substrate; And And a liquid crystal injected between the first substrate and the second substrate. The reflection-transmissive liquid crystal display device according to claim 1, wherein an embossing pattern is formed on an upper surface of the opaque organic film. The liquid crystal display of claim 2, wherein the opaque organic layer is made of a positive black photoresist material. The liquid crystal display of claim 1, wherein a color filter is formed between the second substrate and the common electrode among the pixel areas. The reflective-transmissive liquid crystal display device according to claim 1, wherein the transparent electrode is formed on an upper surface of the reflective electrode. The display device of claim 1, wherein the power supply means comprises a thin film transistor formed in each pixel region, a data line for applying a gray voltage to the thin film transistor, and a gate line for switching the thin film transistor to apply the gray voltage to the pixel electrode. Reflective-transmissive liquid crystal display device comprising a. Forming a power supply means for supplying a first voltage to a plurality of pixel regions formed on the first transparent substrate, forming a contact hole at an output end position of the power supply means, and a light transmitting region through which light passes through each pixel region Forming a formed opaque organic film, forming a reflective electrode in the light reflection region except for the light transmission region of the pixel region through the output terminal for each pixel region, and forming a transparent electrode in the light transmission region through the output terminal 1 manufacturing a substrate; Manufacturing a second substrate by forming a common electrode on the second transparent substrate; And And injecting a liquid crystal between the first substrate and the second substrate. The method of claim 7, wherein the forming of the opaque organic film further comprises forming an embossing pattern on an upper surface of the opaque organic film. The reflective-transmissive liquid crystal display of claim 7, wherein the forming of the pixel electrode comprises forming the reflective electrode on an upper surface of the opaque organic film and then forming the transparent electrode on an upper surface of the reflective electrode. Manufacturing method.