KR100820851B1 - Reflective-transmitted type liquid crystal display and method for manufacturing thereof - Google Patents

Abstract

Disclosed are a reflection-transmissive liquid crystal display device and a method of manufacturing the same, which can improve transmittance and visibility in a transmission mode. A reflection-transmissive liquid crystal display device includes: an array substrate on which a pixel element is formed, the switching element comprising a switching element on the first substrate, a reflection region having a first uneven structure, and a transmissive region having a second uneven structure smaller than the first uneven structure; A color filter and a common electrode are formed on the second substrate, and the color filter substrate is coupled to the array substrate so that the common electrode faces the pixel electrode, and a liquid crystal layer injected between the array substrate and the color filter substrate. do. Therefore, the transmittance and visibility in the transmissive mode can be improved by minimizing the cell gap variation in the transmissive region of the reflection-transmissive liquid crystal display.

Description

REFLECTIVE-TRANSMITTED TYPE LIQUID CRYSTAL DISPLAY AND METHOD FOR MANUFACTURING THEREOF

1 is a cross-sectional view illustrating a general reflection-transmissive liquid crystal display device.

2 is a cross-sectional view illustrating in detail a reflective-transmissive liquid crystal display device according to an exemplary embodiment of the present invention.

3A to 3I are diagrams specifically illustrating a manufacturing process of the reflection-transmissive liquid crystal display shown in FIG. 2.

4 is a cross-sectional view illustrating in detail a reflective-transmissive liquid crystal display device according to another exemplary embodiment of the present invention.

5A through 5D are diagrams illustrating a manufacturing process of the TFT substrate illustrated in FIG. 4.

6 is a graph showing a change in transmittance according to Δnd.

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

200, 600: TFT substrate 220, 620: TFT

230, 630: organic insulating film 232: first unevenness

233: second unevenness 240, 640: transparent electrode

250, 650: reflective electrode 300, 700: color filter substrate                 

400 and 800: liquid crystal layer 500 and 900: reflection-transmissive liquid crystal display device

The present invention relates to a reflection-transmissive liquid crystal display device and a method for manufacturing the same, and more particularly, to provide a reflection-transmissive liquid crystal display device and a method for manufacturing the same that can improve transmittance and visibility in a transmission mode.

In today's information society, the role of display devices becomes more and more important, and various display devices are widely used in various industrial fields. BACKGROUND With the rapid advance of semiconductor technology, liquid crystal display devices having thin and light display devices and low power consumption are widely used in accordance with the miniaturization and light weight of various information processing devices.

The liquid crystal display is classified into a reflective liquid crystal display device that receives an external first light and displays an image and a transmissive liquid crystal display device that receives an internally generated second light and displays an image. Recently, in order to realize high quality images while reducing power consumption, a reflection-transmissive liquid crystal display device utilizing both the advantages of the reflective liquid crystal display and the transmissive liquid crystal display has been developed.

Such a reflection-transmissive liquid crystal display displays an image in a reflection mode using the first light in a place where the external light amount is abundant, and uses a second light generated by consuming electric energy charged in itself when the external light amount is insufficient. Display the image in the transmission mode used.

Recently, the reflection-transmissive liquid crystal display has been developed to have a structure suitable for improving the image quality in the reflection mode. Typical reflection-transmissive liquid crystal display devices that meet this trend are as follows.

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

Referring to FIG. 1, a general reflection-transmissive liquid crystal display device 100 includes a thin film transistor (hereinafter, referred to as TFT) substrate 60 and a color filter substrate 70 that is provided to face the TFT substrate 60. And a liquid crystal layer 80 injected between the TFT substrate 60 and the color filter substrate 70.

The TFT substrate 60 is a substrate on which a plurality of TFTs 20 and pixel electrodes 40 and 50 are formed on the first substrate 10. The plurality of TFTs 60 are formed on the first substrate 10, and the organic insulating layer 30 is coated thereon. The pixel electrodes 40 and 50 in contact with the drain electrode 26 are formed on the organic insulating layer 30.

The pixel electrodes 40 and 50 simultaneously include the reflective electrode 50 and the transparent electrode 40. In detail, when the transparent electrode 40 is formed on the organic insulating layer 30, the reflective electrode is stacked thereon. In this case, the reflective electrode 50 is formed with a transmission window 51 exposing the transparent electrode 40. Therefore, in the reflection mode, the image is reflected by the reflective electrode 50 for reflecting the first light L1 incident through the color filter substrate 70 and outputting the light to the outside through the color filter substrate 80 again. Is displayed. In the transmission mode, the second light L2 incident from the light source unit (not shown) disposed on the rear surface of the TFT substrate 10 is exposed by the transparent electrode 50 exposed by the transmission window 51. Display the video.

In this case, in order to increase the amount of reflection of the first light L1 reflected by the reflective electrode 50 and to improve the viewing angle of the reflection-transmissive liquid crystal display 100, the surface of the organic insulating layer 30 may be increased. A process for forming a plurality of irregularities 35 is performed. The plurality of irregularities 35 includes a convex portion 35a and a concave portion 35b having a relative height from the first substrate 10. The process of forming the unevenness 35 in the organic insulating film 30 is called an "embossing process". Since the embossing process is performed with respect to the entire organic insulating layer 30, a plurality of irregularities 35 are formed on the entire organic insulating layer 30.

Thereafter, the transparent electrode 40 and the reflective electrode 50 are sequentially stacked on the organic insulating layer 30. In this case, since the transparent electrode and the reflective electrode are stacked with a uniform thickness, the surface structures of the transparent electrode 40 and the reflective electrode 50 are also formed in the same manner as the organic insulating layer 30.

The reflective electrode 50 having such a surface structure increases the amount of reflection of the first light L1 and reflects the light at various angles. Thus, visibility and viewing angle in the reflection mode are improved.

However, the unevenness formed in the transparent electrode shifts the polarization state of the second light L2. Specifically, since the unevenness is formed even on the surface of the transparent electrode by the embossing process, the variation of the cell gap of the reflection-transmissive liquid crystal display is largely generated. In other words, the cell gap is caused to be about the size of unevenness deliberately formed by the embossing process. However, when a large gap in the cell gap of the reflection-transmissive liquid crystal display occurs, there is a problem that the transmittance in the transmission mode is reduced and further, the visibility is lowered.

Although not shown in the drawings, the following reflection-transmissive liquid crystal display device has been proposed as a structure for solving such a problem.

The reflection-transmissive liquid crystal display device has a structure in which the surface of the transparent electrode is formed to be flat to correspond to the transmission region. Specifically, an organic insulating layer is formed on the first substrate on which the TFT is formed. Thereafter, the organic insulating layer corresponding to the reflective region is exposed to form irregularities, and at the same time, the organic insulating layer corresponding to the transmissive region is completely removed. This completes the organic insulating film.

Thereafter, the transparent electrode is laminated on the organic insulating layer with a uniform thickness. Here, the transparent electrode has a concave-convex structure in the reflection region, and a flat surface structure in the transmission region.

In this structure, the cell gap in the transmission region is greatly raised because the organic insulating film corresponding to the transmission region is completely removed. In this case, in the reflection-transmissive liquid crystal display device, it is preferable that Δnd (where n is refractive index anisotropy and d is a cell gap) has a value of about half that of the transmissive liquid crystal display device. However, when the cell gap of the reflection-transmissive liquid crystal display is increased by removing the organic insulating layer, a problem may occur in that the transmittance of the reflection-transmissive liquid crystal display is lowered.

An object of the present invention for solving the above problems is to provide a reflection-transmissive liquid crystal display device that can improve the transmittance and visibility in the transmission mode.

Another object of the present invention is to provide a method of manufacturing a reflection-transmissive liquid crystal display device.

The reflection-transmissive liquid crystal display device for achieving the above object of the present invention is a transmissive element having a switching element on the first substrate, a reflection region having a first uneven structure and a second uneven structure smaller than the first uneven structure. An array substrate on which pixel electrodes including regions are formed; A color filter substrate on the second substrate, the color filter substrate being formed on the second substrate and coupled to the array substrate such that the common electrode faces the pixel electrode; And a liquid crystal layer injected between the array substrate and the color filter substrate.

In addition, a method of manufacturing a reflection-transmissive liquid crystal display device for achieving another object of the present invention includes (a) a switching element formed on a first substrate, a reflective region having a first uneven structure, and a first uneven structure. Forming a pixel electrode including a transmissive region having a small second uneven structure to fabricate an array substrate, (b) sequentially manufacturing a color filter substrate and a common electrode on the second substrate to manufacture a color filter substrate; (c) aligning the array substrate and the color filter substrate so that the pixel electrode and the common electrode face each other, and (d) forming a liquid crystal layer between the array substrate and the color filter substrate. .                     

According to the reflection-transmissive liquid crystal display device and a method of manufacturing the same, a first region having first unevenness formed on the first substrate and a second region having second unevenness having a size smaller than the first unevenness are formed. An organic insulating film is formed. In this case, the first region is a reflection region, and the second region is a transmission region. Accordingly, the reflection-transmissive liquid crystal display device may improve transmittance and visibility in the transmission mode by minimizing cell gap variation in the transmission region.

Hereinafter, with reference to the accompanying drawings, it will be described in detail an embodiment of the present invention.

2 is a cross-sectional view illustrating in detail a reflective-transmissive liquid crystal display device according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the reflection-transmissive liquid crystal display device 500 according to an embodiment of the present invention includes a TFT substrate 200, a color filter substrate 300 provided to face the TFT substrate 200, The liquid crystal layer 400 is injected between the TFT substrate 200 and the color filter substrate 300.

The TFT substrate 200 includes a first substrate 210, a TFT 220 formed on the first substrate 210, and an organic layer formed on the first substrate 210 including the TFT 220. The insulating layer 230 and the pixel electrode including the transparent electrode 240 and the reflective electrode 250 are included on the organic insulating layer 230.

The TFT 220 has a gate electrode 221, a source electrode 225, and a drain electrode 226. In this case, the gate electrode 221 is insulated from the source electrode 225 and the drain electrode 226 through the gate insulating layer 222. As power is applied to the gate electrode 221 on the gate insulating layer 222, an active pattern 223 and an ohmic contact pattern 224 for applying power to the drain electrode 226 from the source electrode 225. Is formed. Source and drain electrodes 225 and 226 are formed thereon.

In this case, the organic insulating layer 230 is interposed between the TFT 220 and the transparent electrode 240. Therefore, a contact hole 231 for exposing the drain electrode 226 is formed in the organic insulating layer 230. In addition, a plurality of first unevennesses 232 and a plurality of second unevennesses 233 having a smaller size than the first unevennesses 232 are formed on the surface of the organic insulating layer 230. Here, the region in which the first unevenness 232 is formed is a reflection region R displaying an image by the reflective electrode 350, and the region in which the second unevenness 233 is formed is formed in the transparent electrode 340. Is a transmission region T for displaying an image.

On the other hand, the first concave-convex 232 forms a first convex portion 232a and a first concave portion 232b having a relative height from the first substrate 210. In addition, the second unevenness 233 forms a second convex portion 233a and a second concave portion 233b having a relative height from the first substrate 210. At this time, since the size of the second concave-convex 233 is much smaller than the size of the first concave-convex 232, the height difference between the second convex portion 233a and the second concave portion 233b is the first convex portion. It is much smaller than the height difference between 232a and the first concave portion 232b. Here, the height difference between the second convex portion 233a and the second concave portion 233b is preferably 0.2 μm or less.

Since the size of the second unevenness 233 illustrated in FIG. 1 is very small compared to the size of the first unevenness 323, the surface structure of the organic insulating layer 230 in the transmission region T may be substantially flat. Seen as a structure.

Subsequently, the pixel electrode is applied to the organic insulating layer 230, the drain electrode 226 exposed by the contact hole 231, and the sidewall of the contact hole 231 with a uniform thickness. Specifically, on the organic insulating layer 230 and the contact hole 231, a transparent electrode 240 made of indium tin oxide (ITO) or indium zinc oxide (IZO) is formed. Laminated to a uniform thickness. Therefore, the transparent electrode 240 has the same surface structure as the organic insulating layer 230.

In addition, the reflective electrode 250 made of aluminum (Al) having excellent reflectance is stacked on the transparent electrode 240 in a uniform thickness. In this case, the reflective electrode 250 has a transmission window 251 exposing a predetermined region of the transparent electrode 240 is formed. Specifically, the transmission window 251 is formed corresponding to the transmission region (T).

Although not shown, a first alignment layer (not shown) is further formed on the reflective electrode 250 and the transmission window 251. Specifically, the first alignment layer is formed by coating an organic film of a polyimide system on the reflective electrode 250 and the transmission window 251 and then rubbing in a predetermined direction.

Meanwhile, the color filter substrate 300 is a substrate on which the color filter 320, the common electrode 330, and the second alignment layer (not shown) are sequentially formed on the second substrate 310. The color filter substrate 300 is coupled to face the TFT substrate 200 so that the common electrode 330 faces the pixel electrodes 240 and 250. As such, when the color filter substrate 300 and the TFT substrate 200 are coupled to face each other, the liquid crystal layer 400 is injected between the color filter substrate 300 and the TFT substrate 200. Thus, the reflection-transmissive liquid crystal display 500 is completed.

In this case, the reflection-transmissive liquid crystal display 500 has a cell gap as follows. Here, the cell gap is defined as the distance between the TFT substrate 200 and the color filter substrate 300. Specifically, the reflective region R has a first cell gap d1 at the first convex portion 232a and a second cell gap d2 at a first concave portion. It has a 3rd cell gap d3 in a convex part, and has a 4th cell gap d4 in a 2nd concave part, At this time, the deviation of the said 3rd cell gap d3 and the 4th cell gap d4 is 0.2 micrometer or less. In addition, the average value d3 + d4 / 2 of the third cell gap d3 and the fourth cell gap d4 is an average value d1 + d2 / 2 of the first cell gap d1 and the second cell gap d2. It is preferable that the same as).

The reflection-transmissive liquid crystal display 500 formed as described above displays an image in the reflection area R or the transmission area T in response to the amount of external light.

In detail, the reflection area R displays an image by the first light L1 incident through the color filter substrate 300. This is defined as the reflection mode. The reflection mode is used when the amount of external light is sufficient to implement the screen. In the reflective mode, the first light L1 is reflected by the reflective electrode 250 and then provided to the liquid crystal layer 400. Thereafter, the first light L1 is controlled by the liquid crystal layer 400 to be provided to the color filter substrate 300. Thus, the reflection-transmissive liquid crystal display 500 may implement a screen having a wide viewing angle in the reflection mode.

Meanwhile, in the transmission region T, an image is displayed by the second light L2 generated by the reflection-transmissive liquid crystal display 500 itself and incident through the first substrate 210. This is defined as the transmission mode. The transmission mode is used when the amount of external light is insufficient to implement the screen. In the transmission mode, the second light L2 is sequentially provided through the first substrate 210, the transparent electrode 240, and the transmission window 251, and then provided to the liquid crystal layer 400.

In this case, the second concave-convex 233 having a much smaller size than the first concave-convex 232 formed in the reflective region R is formed in the transmission region T, so that the polarization state of the second light L2 is formed. I'm out without changing the path. Thereafter, the second light L2 passing through the transparent electrode 240 is controlled by the liquid crystal layer 400 and provided to the color filter substrate 300. As a result, the reflection-transmissive liquid crystal display 500 may increase the transmittance of the second light L2 and improve visibility in realizing the screen in the transmission mode.

Hereinafter, a process of manufacturing the reflection-transmissive liquid crystal display 500 shown in FIG. 3 will be described in detail with reference to the drawings.

3A to 3I are views illustrating a manufacturing process of the reflection-transmissive liquid crystal display shown in FIG. 2 in detail.

Referring to FIG. 3A, sputtering a first metal film (not shown) made of aluminum (Al), chromium (Cr), or molybdenum tungsten (MoW) on a first substrate 210 made of an insulating material such as glass or ceramic. After deposition by the method, the first metal film is patterned to form a gate electrode 221.

Subsequently, silicon nitride is deposited on the entire surface of the first substrate 210 on which the gate electrode 221 is formed by plasma-enhanced chemical vapor deposition (PECVD) to form a gate insulating layer 222. do.

An amorphous silicon film is deposited on the gate insulating film 222 as an active layer (not shown), for example, by PECVD, and an n ⁺ doped amorphous silicon film is deposited thereon, as an ohmic contact layer (not shown), by PECVD. Deposit. In this case, the amorphous silicon film and the n ⁺ doped amorphous silicon film are deposited in-situ in the same chamber of the PECVD facility. Subsequently, the ohmic contact layer and the active layer are sequentially patterned to form an active pattern 223 made of an amorphous silicon film on the gate insulating layer 222 on the gate electrode 221 and an ohmic contact layer made of an n ⁺ doped amorphous silicon film. Pattern 224 is formed.

After depositing a second metal film (not shown) such as chromium (Cr) on the entire surface of the resultant by a sputtering method, the second metal film is patterned to form a source electrode 225 and a drain electrode 226. Subsequently, the exposed ohmic contact pattern 224 between the source electrode 225 and the drain electrode 226 is removed by a reactive ion etching (RIE) method.                     

Accordingly, the TFT including the gate electrode 221, the active pattern 223, the ohmic contact layer pattern 224, the source electrode 225, and the drain electrode 226 is formed on the first substrate 210. 220 is formed.

Referring to FIG. 3B, a photosensitive organic insulating layer 235 such as an acrylic resin is coated on the entire surface of the first substrate 210 on which the TFT 220 is formed by spin-coating or slit-coating.

Referring to FIG. 3C, a first mask 260 having a predetermined pattern is formed on the organic insulating layer 235. The first mask 260 is an exposure area A in which a first opening 261 corresponding to the first concave portion 232b is formed to form the first unevenness 232 in the reflection area R. FIG. And a slit exposure area B in which a second opening portion 262 corresponding to the second concave portion 233b is formed so as to form second unevenness 233 in the transmission region T. The first mask 260 further includes a contact hole forming region C exposing a portion of the drain electrode 226.

In this case, the width w1 of the first opening 261 formed in the exposure area A is much smaller than the width w2 of the second opening 262 formed in the slit exposure area B. Therefore, the exposure amount at the second opening 262 is much smaller than the exposure amount at the first opening 261. Thereafter, the organic insulating layer 235 is exposed, and then developed using a tetramethyl-ammonium hydroxide (TMAH) developer. Then, the first uneven pattern 235a and the second uneven pattern 235b having a smaller size than the first uneven pattern 235a are formed in the organic insulating layer 235 while the exposed region is removed. In addition, a contact hole 231 exposing the drain electrode 226 is formed in the contact hole forming region C.

Referring to FIG. 3D, the organic insulating layer 235 is hard-baked for the purpose of reflow, outgassing, and solvent removal. Thereafter, curing is performed at a temperature of about 200 ° C. or more for at least 1 hour to cure and stabilize the organic insulating layer 235. The curing step is carried out to further enhance the hard-baking effect.

At this time, the first and the first through the reflow of the organic insulating layer 235 by performing a hard-baking process and a curing process in the furnace (furnace) or oven (270) for 1 hour at 200 ℃ 2 Adjust the inclination of the uneven patterns 235a and 235b. Accordingly, the organic insulating layer 230 having the first unevenness 232 having the adjusted inclination is formed in the reflection region R, and the second unevenness 233 having the adjusted inclination is formed in the transmission region T. Is completed.

Referring to FIG. 3E, a transparent conductive film such as ITO or IZO is deposited on the organic insulating layer 230 and the contact hole 231 to a uniform thickness to form a transparent electrode 240. The transparent electrode 240 is connected to the drain electrode 226 of the TFT 220 through the contact hole 231. In this case, the transparent electrode 240 has the same surface structure as that of the organic insulating layer 230 because the transparent electrode 240 is laminated on the organic insulating layer 230 with a uniform thickness.

Next, referring to FIG. 3F, the reflective electrode layer 255 is formed on the transparent electrode 240 by depositing a metal layer having excellent reflectance such as aluminum with a uniform thickness. 3G, a second mask 280 having a predetermined pattern is formed on the reflective electrode layer 255. In detail, an opening 281 is formed in the second mask 280 to expose the reflective electrode layer 255 corresponding to the transmission region T.

Next, when the reflective electrode layer 255 is exposed and developed using a developing solution, the reflective electrode layer 255 is removed from the portion corresponding to the transparent region T while the transparent electrode 240 is exposed. The reflective electrode 250 having the window 251 is formed. Thus, the TFT substrate 200 is completed.

Referring to FIG. 3H, the color filter substrate 300 is formed by sequentially stacking the color filter 320, the common electrode 330, and the second alignment layer (not shown) on the second substrate 310. . Subsequently, referring to FIG. 3I, the TFT substrate 200 and the color filter substrate 300 are aligned. Specifically, the TFT substrate 200 and the color filter substrate 300 are disposed such that the reflective electrode 250 and the common electrode 330 face each other.

Next, referring to FIG. 2, the liquid crystal layer 400 is formed between the TFT substrate 200 and the color filter substrate 300, thereby completing the reflection-transmissive liquid crystal display device 500.

6 is a graph showing a change in transmittance according to Δnd. Here, n is refractive anisotropy and d is a cell gap of the reflection-transmissive liquid crystal display device.

Referring to FIG. 6, the transmittance of the reflection-transmissive liquid crystal display becomes maximum when Δnd is 0.24 μm. Since n is a fixed constant, it is important to adjust the cell gap d of the reflection-transmission liquid crystal display device in order to maximize the transmittance of the reflection-transmission liquid crystal display device.

As shown in FIG. 1, which is a conventional drawing, when the cell gap in the transmission mode is greatly changed, the transmittance is also changed accordingly. This change in transmittance ultimately lowers the contrast ratio (C / R) of the reflection-transmissive liquid crystal display device, and further reduces visibility. However, as shown in FIG. 2, which is a diagram of the present invention, the change in transmittance is also minimized in the reflection-transmissive liquid crystal display device in which the cell gap variation in the transmission mode is minimized. Thus, contrast ratio and visibility of the reflection-transmissive liquid crystal display device are improved.

4 is a cross-sectional view illustrating in detail a reflective-transmissive liquid crystal display device according to another exemplary embodiment of the present invention.

Referring to FIG. 4, the reflection-transmissive liquid crystal display device 900 according to another embodiment of the present invention includes a TFT substrate 600, a color filter substrate 700 provided to face the TFT substrate 620, The liquid crystal layer 800 is injected between the TFT substrate 600 and the color filter substrate 700.

The TFT substrate 600 includes a first substrate 610, a TFT 620 formed on the first substrate 610, and an organic layer formed on the first substrate 610 including the TFT 620. The insulating layer 630 includes a pixel electrode including a transparent electrode 640 and a reflective electrode 650 on the organic insulating layer 630.

The organic insulating layer 630 is divided into a region having a plurality of irregularities 632 and a region having a flat surface structure. Here, the region where the plurality of irregularities 632 is formed is a reflective region R for displaying an image by the reflective electrode 650, and the region having the flat surface structure is formed by the transparent electrode 640. It is a transmission area T displaying an image. A contact hole 631 is formed in the organic insulating layer 630 to expose the drain electrode 626. The unevenness 632 includes a convex portion 632a and a concave portion 632b having a relative height from the first substrate 610.

On the organic insulating layer 630, a transparent electrode 640 made of ITO or IZO is stacked with a uniform thickness. Therefore, the transparent electrode 640 has the same surface structure as the organic insulating layer 630. On the transparent electrode 640, a reflective electrode 650 having a transmission window 651 exposing the transparent electrode 640 on a portion corresponding to the transmission region T is stacked with a uniform thickness. Therefore, in the reflective region R, the reflective electrode 650 has a concave-convex structure, and has a flat surface structure in the transmissive region T where the transmissive window 651 is formed. Although not shown in the drawings, a first alignment layer (not shown) is further formed on the reflective electrode 650 and the transmission window 651.

The color filter substrate 700 is a substrate on which the color filter 720, the common electrode 730, and the second alignment layer (not shown) are sequentially formed on the second substrate 710. The color filter substrate 700 is coupled to face the TFT substrate 600 such that the common electrode 730 faces the pixel electrodes 640 and 650. As such, when the color filter substrate 700 and the TFT substrate 600 are coupled to face each other, the liquid crystal layer 800 is injected between the color filter substrate 700 and the TFT substrate 600. Thus, the reflection-transmissive liquid crystal display device 900 is completed.                     

In this case, the reflection-transmissive liquid crystal display device 900 has a cell gap as follows. Here, the cell gap is defined as the distance between the TFT substrate 600 and the color filter substrate 700. Specifically, the reflective region R has a first cell gap d1 at the convex portion 632a and a second cell gap d2 at the concave portion 632b. On the other hand, the transmission region T has a uniform third cell gap d3 because the surface is flat. Specifically, the third cell gap d3 may be larger than the first cell gap d1 and smaller than the second cell gap d2. More preferably, the third cell gap d3 is an average value d1 + d2 / 2 of the first cell gap d1 and the second cell gap d2.

Hereinafter, a process of manufacturing the reflection-transmissive liquid crystal display device 900 shown in FIG. 4 will be described in detail with reference to the drawings.

5A to 5C are views illustrating a manufacturing process of the TFT substrate illustrated in FIG. 4.

Referring to FIG. 5A, a photosensitive organic insulating layer 635 such as an acrylic resin is coated on the entire surface of the first substrate 610 on which the TFT 620 is formed by spin-coating or slit-coating.

Referring to FIG. 5B, a third mask 660 having a predetermined pattern is formed on the organic insulating layer 635. The third mask 660 includes an exposure area A in which openings 661 are formed corresponding to the recess 632a to form the unevenness 632 in the reflection area R, and the transmission area ( It has a partial exposure area B for adjusting the cell gap while making the surface of T) flat. In addition, the third mask 660 further includes a contact hole forming region C exposing a portion of the drain electrode 626. In this case, the thickness t1 of the third mask 660 in the exposure area A is thinner than the thickness t2 of the third mask 600 in the partial exposure area B. FIG.

Thereafter, the organic insulating layer 635 is exposed, and then developed using a tetramethyl-ammonium hydroxide developer. Then, as the exposed region of the organic insulating layer 635 is removed, an unevenness 632 is formed in the organic insulating layer 635 corresponding to the reflective region R, and corresponding to the transmission region T. It is formed into a flat surface structure. In the contact hole forming region C, a contact hole 631 exposing the drain electrode 626 is formed.

Referring to FIG. 5C, the organic insulating layer 635 is hard-baked for the purpose of reflow, outgassing, and solvent removal. Thereafter, the organic insulating layer 635 is cured at a temperature of about 200 ° C. or more for at least 1 hour to form a cured and stabilized organic insulating layer 630.

Referring to FIG. 5D, the TFT substrate 600 is completed by sequentially forming the transparent electrode 640 and the reflective electrode 650 on the organic insulating layer 630.

According to the above-described reflection-transmissive liquid crystal display device and a method of manufacturing the same, a first region having first unevenness formed on the first substrate and a second region having second unevenness having a size smaller than the first unevenness are formed. An organic insulating film is formed. In this case, the first region is a reflection region, and the second region is a transmission region.

Accordingly, the reflection-transmissive liquid crystal display device may improve transmittance and visibility in the transmission mode by minimizing cell gap variation in the transmission region.

In addition, in order to minimize the cell gap variation of the transmission region, since only the size of the unevenness is adjusted in the process of performing the conventional embossing process, the process may be performed using a separate mask or without an additional process.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

Claims (8)

An array substrate including a switching element, a pixel electrode including a switching element, a reflective region having a first uneven structure, and a transmissive region having a second uneven structure smaller than the first uneven structure; A color filter substrate on the second substrate, the color filter substrate being formed on the second substrate and coupled to the array substrate such that the common electrode faces the pixel electrode; And And a liquid crystal layer injected between the array substrate and the color filter substrate. The method of claim 1, wherein the array substrate, A switching element formed on one surface of the first substrate; A contact hole exposing a part of the switching element is formed on the first substrate on which the switching element is formed, and includes a first region in which first unevenness is formed and a second region in which second unevenness is smaller than the first unevenness; Insulating film; And A pixel comprising a transparent electrode provided with a uniform thickness on the insulating layer and the contact hole, and a reflective electrode provided with a uniform thickness on the transparent electrode and having a transmission window for exposing the transparent electrode corresponding to the second region. Liquid crystal display comprising an electrode. The reflection-transmissive liquid crystal display device according to claim 1, wherein the surface of the pixel electrode is flat in the transmission region and the cell gap in the transmission region is constant. The said 1st uneven structure is a convex part and a recessed part, The said permeation | transmission area | region is made when the cell gap in the said convex part is made into a 1st cell gap, and the cell gap in the said recessed part is made into a 2nd cell gap. Wherein the cell gap is larger than the first cell gap and smaller than the second cell gap. The said 1st uneven structure is a convex part and a recessed part, The said permeation | transmission area | region is made when the cell gap in the said convex part is made into a 1st cell gap, and the cell gap in the said recessed part is made into a 2nd cell gap. Wherein the cell gap is calculated by an arithmetic mean of the first cell gap and the second cell gap. (a) forming a pixel electrode including a switching element formed on a first substrate, a reflective electrode having a first uneven structure, and a transmissive area having a second uneven structure smaller than the first uneven structure, thereby manufacturing an array substrate; step; (b) sequentially manufacturing a color filter substrate by laminating a color filter and a common electrode on a second substrate; (c) aligning the array substrate and the color filter substrate such that the pixel electrode and the common electrode face each other; And (d) forming a liquid crystal layer between the array substrate and the color filter substrate. The method of claim 6, wherein step (a) is (a-1) forming a switching device on the first substrate; (a-2) A contact hole exposing a part of the switching element is formed on the first substrate on which the switching element is formed, and a first region in which first unevenness is formed and a second unevenness smaller than the first unevenness are formed. Stacking an insulating film including a second region; (a-3) forming a transparent electrode on the insulating layer and the contact hole with a uniform thickness; And (a-4) A method of manufacturing a reflection-transmissive liquid crystal display device, the method comprising: stacking a reflective electrode having a transmission window for exposing the transparent electrode corresponding to the second region on the transparent electrode with a uniform thickness. The method of claim 7, wherein step (a-2), Applying an insulating film on the first substrate on which the switching element is formed; Forming a mask including an exposure region having a first opening having a first width and a slit exposure region having a second opening having a second width smaller than the first width on the insulating film; Exposing and developing the insulating film; And And baking the insulating film at a predetermined temperature.

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