KR101071260B1 - Transflective liquid crystal display - Google Patents

Abstract

The present invention relates to a transflective liquid crystal display device and a method of manufacturing the same, which can simplify a manufacturing process while reducing the color reproducibility difference between a reflection mode and a transmission mode, and is formed on a first substrate and the first substrate. A translucent film having a depression in the region, a color filter formed on the translucent film and having a different thickness depending on the position by the depression of the translucent film, a transparent electrode electrically connected to the drain electrode, and positioned in the reflective region And a reflective electrode formed between the light transmitting film and the color filter, a second substrate, a common electrode formed on the second substrate, and a liquid crystal layer interposed between the first substrate and the second substrate. A liquid crystal display device and a manufacturing method thereof are provided.

As described above, the present invention forms a depression in the transmissive film of the transmissive window of the transmissive region and stacks the color filters thereon to form a color filter layer thicker than the color filter layer of the transmissive region, thereby reducing the difference in color reproducibility between the two modes. By forming depressions in the overcoat layer of the region, cell gaps between the two modes are formed differently to reduce the optical characteristic difference.

Reflective Liquid Crystal Display, Cell Gap, Color Reproducibility

Description

Reflective type liquid crystal display device {TRANSFLECTIVE LIQUID CRYSTAL DISPLAY}

1 is a cross-sectional view of a typical reflective liquid crystal display device.

2 is a cross-sectional view of a transflective liquid crystal display device according to an exemplary embodiment of the present invention.

3 is a cross-sectional view of a transflective liquid crystal display device according to another exemplary embodiment of the present invention.

4 is a cross-sectional view of a transflective liquid crystal display device according to still another exemplary embodiment of the present invention.

5A through 5F are manufacturing process diagrams of an array substrate of a transflective liquid crystal display device according to an exemplary embodiment of the present invention.

6A to 6D are manufacturing process diagrams of a common electrode substrate of a transflective liquid crystal display according to an exemplary embodiment of the present invention.

<< Explanation of symbols for main part of drawing >>

110, 210, and 510: first insulating substrate

120, 220, 520: thin film transistor

121, 221, and 521 gate electrodes

122, 222, 522: gate insulating film

123, 223, 523: source electrode                 

124, 224, and 524 drain electrodes

226 and 526: semiconductor layers

527: ohmic contact layer

130: organic film

230, 530: light transmitting film

231, 531, 531`: contact hole

232: transmission window

140 and 240: pixel electrodes

141, 241, 341, 441, 541: transparent electrode

142, 242, 342, 442, 542: reflective electrode

160, 260, 560: array substrate

150, 250, 450, 550: color filter layer

171, 271, 671: second insulating substrate

272, 672: overcoat layer

274, 674: overcoat layer depression

173, 273, 673: common electrode

170: color filter substrate

270, 670: common electrode substrate

590: first pattern mask

675: second pattern mask

The present invention relates to a transflective liquid crystal display substrate and a method of manufacturing the same.

According to an operation mode, a liquid crystal display is classified into a transmissive liquid crystal display that receives light generated from a backlight disposed on the back of the display panel and displays an image, and a reflective liquid crystal display that receives light from the outside of the device and displays an image.

In recent years, the mobility of the display device is increased, and both the power consumption and the advantages of the reflective liquid crystal display with good visibility in the bright outdoors and the visibility of the transmissive liquid crystal display with good visibility in the dark room are fully utilized, and are not affected by the ambient light. In order to secure visibility, the use of a transflective liquid crystal display is increasing.

1 is a diagram illustrating a conventional reflective transmissive liquid crystal display substrate.

Referring to FIG. 1, in the conventional reflective liquid crystal display substrate, the array substrate 160 having the thin film transistor 120, the color filter 150, and the common electrode 173 are formed to face the array substrate 170. The liquid crystal layer 180 is interposed between the common electrode substrate 173 and the array substrate 160 and the color filter substrate 170.

The array substrate 160 includes a thin film transistor 120 formed on the first insulating substrate 110, a transparent electrode 141 and a reflective electrode 142 forming the pixel electrode part 140 and electrically connected to the thin film transistor. And an organic layer 130 interposed between the thin film transistor 120 and the pixel electrode unit 140, and the reflective region B on which the reflective electrode 142 is formed and the reflective electrode 142 are opened to open the transparent electrode. 141 is divided into the exposed transmissive region A. FIG.

The color filter substrate 170 includes a color filter layer 150 formed on the second insulating substrate 171 and a common electrode 173 covering the color filter layer 150.

The liquid crystal display substrate 100 having such a structure displays an image by reflecting the external light L1 incident through the color filter substrate 170 from the reflective electrode 142 and outputting the light through the color filter substrate 170 again. And a transmission mode for displaying an image by emitting the backlight light L2 incident from the rear surface of the array substrate 160 through the color filter substrate 170.

In this structure, since the external light L1 of the reflection mode passes through the color filter layer twice, the backlight light L2 of the transmission mode passes through the color filter layer once, thereby causing a difference in color reproducibility between the two modes.

In addition, since the length of the optical path experienced by the external light L1 in the reflective mode is about 2d, the length of the optical path experienced by the backlight light L2 in the transmissive mode varies by d, so There is a problem that a difference in optical characteristics occurs.

Accordingly, an object of the present invention is to provide a reflective liquid crystal display device and a manufacturing method thereof in which the difference in color reproducibility between the reflection mode and the transmission mode is minimized.                         

Another object of the present invention is to provide a reflection type liquid crystal display device and a method of manufacturing the same, which minimize the difference in optical characteristics between the two modes by making the lengths of the optical paths experienced by the light in the reflection mode and the transmission mode the same.

The reflective liquid crystal display device of the present invention for achieving the above technical problem is formed on the first substrate, the first substrate, the light-transmitting film having a depression in the transmission region, formed on the light-transmissive film, the depression of the light-transmitting film A color filter having a thickness different according to the position by the negative electrode, a transparent electrode electrically connected to the drain electrode, and a reflective electrode positioned between the light-transmitting film and the color filter and positioned in the reflective region, and a second substrate. And a common electrode formed on the second substrate, and a liquid crystal layer interposed between the first substrate and the second substrate.

The liquid crystal display includes a gate electrode formed on the first substrate, a semiconductor layer positioned above or below the gate electrode and insulated from the gate electrode, and a source / drain electrode connected to the semiconductor layer. It may further include a thin film transistor.

In addition, according to an embodiment of the present invention, the liquid crystal display further includes an insulating layer formed between the second substrate and the common electrode, and the insulating layer has a depression facing the depression of the light-transmitting film. have.

In addition, according to an embodiment of the present invention, the depression of the insulating layer has a depth substantially the same as the thickness of the color filter in the reflection area.

In addition, according to an embodiment of the present invention, the recessed portion of the translucent film has a thickness of zero.

In addition, according to an embodiment of the present invention, the light-transmissive film has a concave-convex structure on the surface, and the reflective electrode has a concave-convex structure along the concave-convex structure on the surface of the light-transmissive film.

In addition, according to an embodiment of the present invention, the surface of the color filter is uniform in height.

In addition, according to an embodiment of the present invention, the thickness of the color filter is twice that of the reflection area in the transmission area.

In addition, according to an embodiment of the present invention, the transparent electrode may be positioned between the light transmissive layer and the reflective electrode, between the first insulating substrate and the light transmissive layer, or on the color filter.

According to an embodiment of the present invention, the liquid crystal layer includes a plurality of liquid crystal molecules arranged in the same direction in parallel with the first and second substrates when there is no electric field, and the reflective liquid crystal display device is The display device may further include an alignment layer formed on the color filter and the transparent electrode. Alternatively, the liquid crystal layer may include a plurality of liquid crystal molecules vertically aligned with respect to the first and second substrates when there is no electric field.

According to an aspect of the present invention, there is provided a method of manufacturing a reflective transmissive liquid crystal display substrate, the method comprising: forming a thin film transistor on a first substrate, forming a light transmitting film having depressions on the thin film transistor and the first substrate, Forming a transparent electrode on the film, forming a reflective electrode on a portion other than the depression of the light-transmitting film on the transparent electrode, forming a color filter layer on the reflective electrode and the light-transmitting film, transparent electrode on the color filter layer Forming an insulating layer on the second substrate, forming a common electrode on the insulating layer, aligning the first substrate and the second substrate, and forming the first substrate and the second substrate. Interposing a liquid crystal between the substrates.

In addition, according to an embodiment of the present invention, the method of manufacturing a reflective transmissive liquid crystal display substrate further includes forming an embossing structure on the surface of the transmissive film by slit exposing the translucent film.

In addition, according to an embodiment of the present invention, the method of manufacturing a reflective liquid crystal display substrate further includes forming a recess by removing at least a portion of the insulating layer at a position facing the recess of the light-transmitting layer.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

2, 3, and 4 are cross-sectional views of a transflective liquid crystal display substrate according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the liquid crystal display substrate according to the present exemplary embodiment includes an array substrate 260 facing each other, a common electrode substrate 270, and a liquid crystal layer 280 positioned between the two substrates 260 and 270. do.

The array substrate 260 is a substrate on which a plurality of thin film transistors 220, a transparent film 230, and a color filter layer 250 are formed on an insulating substrate 210 made of an insulating material such as glass, quartz, or sapphire.

The thin film transistor 220 includes a gate electrode 221, a gate insulating layer 222, a semiconductor layer 226, a source electrode 223, and a drain electrode 224. As illustrated in FIG. 2, the thin film transistor 220 may be a lower gate type in which the gate insulating layer 222 and the semiconductor layer 226 are sequentially stacked on the gate electrode 221, or conversely, the gate insulating layer may be disposed on the semiconductor layer 226. 222 and an upper gate method (not shown) in which the gate electrodes 221 are sequentially stacked may be used. The semiconductor layer 226 may be amorphous silicon or polycrystalline silicon.

The insulating transparent film 130 is positioned on the thin film transistor 220 and is formed by a spin coating method or the like. The light transmissive layer 130 is formed of a photosensitive organic material including bisbenzocyclobutene (BCB), perfluorocyclobutene (PFCB), or the like, or a photosensitive inorganic insulating material including silicon oxide (SiO ₂ ), silicon nitride (SiNx), or the like. The transmissive film 230 is provided with a contact hole 231 partially exposing the drain electrode 224 and a transmission window 132 through which light L2 from the backlight (not shown) is transmitted. The transmissive window 132 is a portion where the light transmissive layer 230 is completely removed to expose the gate insulating layer 225 to form a step D1 with the surface. However, the transmission window 132 may be made by removing only a part of the thickness of the light transmitting film 230. In addition, although the surface of the light transmissive film 230 has an embossing structure, it may be formed to be substantially flat.

The reflective electrode 242 is formed on the light transmissive film 230 except for the transmission window 232. As described above, the region in which the transmission window 232 is formed constitutes the transmission region A for transmitting the backlight light L2, and the region in which the reflection electrode 242 is formed reflects the external region L1. To achieve. The reflective electrode 242 is made of a metal having excellent reflectivity, such as aluminum (Al), silver (Ag), aluminum-copper (Al-Cu) alloy, aluminum-silicon-copper (Al-Si-Cu) alloy, or the like. The reflective electrodes 242 are stacked to have a uniform thickness and have the same surface structure as the light transmissive film 230. Accordingly, when the surface of the light transmissive film 242 has an embossed structure, the reflective electrode 242 also has an embossed surface, and the embossed structure of the reflective electrode 242 improves reflection characteristics of external light.

The color filter layer 250 is positioned on the transmission window 232 and the reflective electrode 242. As such, by forming the color filter layer 250 on the array substrate 260, misalignment occurring when the color filter layer 250 is formed on the common electrode substrate 270 may be prevented, and the reflective electrode 242 may be prevented. Since the color filter layer 250 having a relatively smooth surface is located thereon, the cell gap calculation in the reflection area B is simplified, and the cell gap between the transmission area A and the reflection area B due to the embossing structure of the reflection electrode 242 is simplified. The difficulty of calculation can be eliminated.

The surface height of the color filter layer 250 is substantially uniform. Accordingly, the thickness D2 of the portion of the color filter layer 250 positioned in the transmission window 232 is greater than the thickness D3 of the portion of the color filter layer 250 due to the step D1 formed in the light transmissive layer 230. thick. By doing in this way, the color reproducibility difference between the transmission area | region A and the reflection area | region B as mentioned above can be solved. Preferably, the thickness D2 of the color filter layer 250 on the transmission window 232 is twice the thickness D3 of the color filter layer 250 on the reflective electrode 242 so that the external light L1 experiences. The length of the color filter layer 250 and the length of the color filter layer 250 experienced by the backlight light L2 are substantially the same. In addition, the thickness of the color filter layer 250 may vary depending on the color indicated by the color filter layer 250.

The transparent electrode 241 is formed on the color filter layer 250, and the transparent electrode 241 is made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The transparent electrode 241 is in electrical contact with the drain electrode 224 and the reflective electrode 242 through the contact hole 231 formed in the light transmissive film 230 and the color filter layer 250. As such, when the transparent electrode 241 is formed on the color filter layer 250, the contact area between the reflective electrode 242 and the transparent electrode 241 may be reduced to reduce the galvanic effect.

The common electrode substrate 270 is a substrate on which an overcoat layer 272 made of a photosensitive material and a common electrode 273 having transparency are formed on an insulating substrate 271 made of an insulating material such as glass, quartz, or sapphire.

A portion of the overcoat layer 272 facing the transmission window 232 of the array substrate 260 is removed to form a recess. Due to the step of the overcoat layer 272, the cell gap d1 of the transmission region A is larger than the cell gap d2 of the reflection region B. In this case, since the optical path experienced by the external light L1 in the reflective mode and the optical path experienced by the backlight light L2 in the transmissive mode have the same length, the optical characteristic difference between the reflective mode and the transmissive mode can be eliminated. . Preferably, the step of the overcoat layer 272 is determined such that the cell gap d1 of the transmissive region A is twice the cell gap d2 of the reflective region B.

The liquid crystal layer 280 is interposed between the array substrate 260 and the common electrode substrate 270. The liquid crystal layer 280 is a twisted nematic (TN) method in which liquid crystal molecules are parallel to the substrate and are twisted 90 degrees in the absence of an electric field, or in a vertically aligned (VA) method in which the liquid crystal molecules are vertically aligned with respect to the substrate in the absence of an electric field. Can be done. In contrast, the liquid crystal layer 280 has liquid crystal molecules parallel to the substrate and arranged in the same direction when there is no electric field, and the transparent electrode 241 of the array substrate 260 and the common electrode of the common electrode substrate 270 ( 273) and may include an alignment layer (not shown) which is formed on each other and rubbed in parallel with each other (ECB mode). The alignment layers (not shown) may be rubbed in opposite directions to each other.                     

Referring to FIG. 3, a transparent electrode 341 is formed between the light transmissive film 230 / gate insulating layer 225 and the reflective electrode 242. Other components other than the transparent electrode 341 are the same as those described with reference to FIG. 2. When the transparent electrode 341 is formed to have a substantially uniform thickness on the light transmissive film 230 and an embossing structure is formed on the surface of the light transmissive film 230, the transparent electrode 341 also has an embossed shape, and the contact hole 231 is formed. In contact with the drain electrode 224 through. As shown in FIG. 3, since the contact area between the two electrodes 241 and 342 is large, a galvanic phenomenon is reduced by selecting a less reactive metal as the material of the two electrodes 241 and 342.

Referring to FIG. 4, a transparent electrode 241 is formed on the same layer as the gate electrode 221 at the bottom of the transmission window 232. The gate insulating layer 225 is opened on the transparent electrode 441, and the light transmissive layer 230 has no contact hole for contact between the reflective electrode 442 and the drain electrode 224. Instead, the drain electrode 224 extends near the transparent electrode 441, and the reflective electrode 442 is formed on the top of the light-transmitting film 230 and on the partition wall of the transmission window 232, so that the drain electrode 224 and It is electrically connected to the transparent electrode 441.

Hereinafter, a process of manufacturing the array substrate 210 will be described in detail with reference to FIGS. 5A to 5F.

5A through 5F are cross-sectional views illustrating in detail a process of manufacturing the array substrate shown in FIG. 2 according to an embodiment of the present invention.

Referring to FIG. 5A, a thin film transistor 520 including a gate electrode 521, a source electrode 525, and a drain electrode 524 is formed on the first insulating substrate 510. Specifically, it is as follows.                     

First, a metal film (not shown) made of aluminum (Al), chromium (Cr), molybdenum tungsten (MoW), or the like is deposited on the insulating substrate 510, and then patterned to form a gate electrode 521. Thereafter, a gate insulating layer 525 made of silicon nitride, silicon oxide, or the like is formed on the gate electrode 521 and the first insulating substrate 510.

Thereafter, an intrinsic amorphous silicon film and an n + amorphous silicon film doped in situ are sequentially stacked on the gate insulating film 525 by a method such as plasma chemical vapor deposition. Next, the stacked intrinsic amorphous silicon film and the n + amorphous silicon film are patterned to form the semiconductor layer 526 and the ohmic contact layer 527 in a region corresponding to the gate electrode. Here, the semiconductor layer 526 may be converted into a polycrystalline silicon layer by irradiating an appropriate laser to the amorphous silicon film.

Next, source and drain electrodes 523 and 524 are formed on the ohmic contact layer 527 and the gate insulating layer 525. As a result, the thin film transistor 520 is formed on the first insulating substrate 510.

5B and 5C, the photosensitive light-transmitting film 530 is coated on the upper surface of the first insulating substrate 510 on which the thin film transistor 520 is formed by a spin coating method or the like. Next, the first pattern mask 590 having a predetermined pattern is disposed on the laminated light-transmitting film 530, and then the light-transmitting film 530 is exposed.

When the exposed light-transmitting film 530 is developed, as shown in FIG. 5C, the light-transmitting film 530 patterned in a predetermined shape is formed. In detail, the transmissive layer 530 is formed with a contact hole 531 partially exposing the drain electrode 524 of the thin film transistor 520 and a transmissive window 532 partially exposing the gate insulating layer 522. . Although not shown here, the embossed structure on the surface of the light transmissive film 530 may be formed through slit exposure.

Referring to FIG. 5D, the reflective electrode 542 is formed on the light transmissive film 530 to have an opening in the transmission window 532. The reflective electrode 542 is electrically connected to the drain electrode 524 through the contact hole 531.

Next, referring to FIG. 5E, the color filter layer 550 is stacked to cover the reflective electrode 542 and the transmission window 532. The color filter layer 550 may have three colors of red, green, and blue, and may have a different thickness for each color. The color filter layer 550 is formed to be substantially flat, and the contact hole 531 ′ is formed at a position corresponding to the contact hole 531 formed in the light transmitting film.

Next, the transparent electrode 541 is formed over the entire color filter layer 550. The transparent electrode 541 has a substantially uniform thickness and is in electrical contact with the drain electrode 524 and the reflective electrode 542 through the contact hole 531 ′.

Hereinafter, a process of manufacturing the common electrode substrate 670 will be described in detail with reference to FIGS. 6A to 6D.

6A through 6D are cross-sectional views illustrating a process of manufacturing the common electrode substrate 270 illustrated in FIG. 2.

Referring to FIG. 6A, an overcoat layer 672 made of a photosensitive material is formed on the insulating substrate 671 by using a spin coating method.

6B and 6C, when the photosensitive material in the region corresponding to the transmission window 532 formed on the array substrate 560 is removed, the patterned second pattern mask 675 may be disposed and developed after exposure. As illustrated in FIG. 6C, a depression 674 is formed in the overcoat layer 672.

Referring to FIG. 6D, a transmissive common electrode 673 is formed on the overcoat layer 673 in which the depression 674 is formed. As a result, the common electrode substrate 670 is completed.

Therefore, according to the liquid crystal display substrate and the manufacturing method thereof according to the present invention described above, the color reproducibility in both regions can be made uniform by forming different thicknesses of the color filter layers between the reflective and transmissive regions.

In addition, when forming the common electrode substrate, the cell gap in the transmission mode may be larger than the cell gap in the reflection mode, thereby reducing the optical characteristic difference due to the cell gap difference between the two modes.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (16)

A reflection-transmissive liquid crystal display device having a reflection area and a transmission area, First substrate, A translucent film formed on the first substrate and having a depression in the transmission region, A color filter formed on the light-transmissive film and having a different thickness depending on the position by the depression of the light-transmissive film, A transparent electrode formed on the color filter, and A reflective electrode electrically connected to the transparent electrode and formed between the light transmitting film and the color filter; Second substrate, A common electrode formed on the second substrate, and Liquid crystal layer interposed between the first substrate and the second substrate Including, And a thickness of the color filter in the transmission area is twice the thickness of the color filter in the reflection area. In claim 1, The semiconductor device may further include a thin film transistor including a gate electrode formed on the first substrate, a semiconductor layer positioned above or below the gate electrode and insulated from the gate electrode, and a source / drain electrode connected to the semiconductor layer. , The transparent electrode and the reflective electrode is connected to the drain electrode Reflective type liquid crystal display device. 3. The method of claim 2, Further comprising an insulating layer formed between the second substrate and the common electrode, The insulating layer has a depression facing the depression of the translucent film Reflective type liquid crystal display device. 4. The method of claim 3, The recessed portion of the insulating layer has a depth substantially equal to the thickness of the color filter in the reflective region. In claim 1, The recessed portion of the light-transmitting film has a zero thickness transmissive liquid crystal display device. In claim 1, The light transmitting film has a concave-convex structure on the surface, The reflective electrode has an uneven structure along the uneven structure of the translucent film surface. Reflective type liquid crystal display device. In claim 1, A reflective transmissive liquid crystal display device having a uniform height on the surface of the color filter. delete delete delete delete In claim 1, The liquid crystal layer includes a plurality of liquid crystal molecules arranged in the same direction parallel to the first and second substrate when there is no electric field Reflective type liquid crystal display device. delete In claim 1, The liquid crystal layer includes a plurality of liquid crystal molecules vertically aligned with respect to the first and second substrates when there is no electric field. Reflective type liquid crystal display device. delete delete

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