KR100993831B1 - Upper substrate, liquid crystal display device having same and manufacturing method thereof - Google Patents

Abstract

An upper substrate capable of improving display characteristics, a liquid crystal display device having the same, and a manufacturing method thereof are disclosed. The liquid crystal display device includes an upper substrate, a lower substrate, and a liquid crystal layer interposed between the upper substrate and the lower substrate. The lower substrate includes a transmission electrode and a reflection electrode on the first substrate to define a reflection area and a transmission area. The upper substrate may include a second substrate, a first insulating film provided in the transmissive region of the second substrate, a transparent electrode provided in the reflective region of the first insulating film and the second substrate, and a second insulating film stacked on the common electrode corresponding to the reflective region. Is done. Therefore, the reflectance of the reflective region and the transmittance of the transmissive region can be improved while maintaining the cell gap of the liquid crystal display device uniformly.

Description

UPPER SUBSTRATE, LIQUID CRYSTAL DISPLAY APPARATUS HAVING THE SAME AND METHOD FOR MANUFACTURING THE SAME

1 is a cross-sectional view showing in detail the upper substrate according to an embodiment of the present invention.

FIG. 2 is a plan view of the upper substrate shown in FIG. 1.

3 is a cross-sectional view showing an upper substrate according to another embodiment of the present invention.

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

5 is a graph illustrating changes in transmittance and reflectance according to voltages applied to the transmission electrode and the reflection electrode.

6A through 6E are cross-sectional views illustrating an embodiment of a manufacturing process of the upper substrate illustrated in FIG. 1.

7A to 7C are cross-sectional views illustrating another example of a manufacturing process of the upper substrate illustrated in FIG. 1.

        <Explanation of symbols for main parts of the drawings>

100: upper substrate 120: color filter layer                 

130 planarization film 140 first insulating film

150: common electrode 160: second insulating film

200: lower substrate 240: transmission electrode

250: reflective electrode 300: liquid crystal layer

400: liquid crystal display

The present invention relates to an upper substrate, a liquid crystal display having the same, and a manufacturing method thereof, and more particularly, to an upper substrate capable of improving display characteristics, a liquid crystal display having the same, and a manufacturing method thereof.

The transflective liquid crystal display displays an image in a reflection mode using external light where the amount of external light is abundant. Display.

The transflective liquid crystal display device includes a liquid crystal display panel including a lower substrate, an upper substrate facing the lower substrate, and a liquid crystal layer interposed between the lower substrate and the upper substrate.

The lower substrate includes a thin film transistor (hereinafter, referred to as TFT), a transparent electrode connected to the drain electrode of the TFT, and a reflective electrode. Here, the region where the reflective electrode is formed on the transparent electrode is a reflective region, and the region where the reflective electrode is not formed on the transparent electrode is a transmission region.

An organic insulating film in which a contact hole for exposing a drain electrode is formed between the TFT and the transparent electrode. Therefore, the transparent electrode is electrically connected to the transparent electrode and the drain electrode through the contact hole.

In general, in order to improve light efficiency and display quality in the reflection mode and the transmission mode, the transflective liquid crystal display device drives the cell gap in the reflection region and the cell gap in the transmission region differently. That is, the cell gap of the reflection area is half of the cell gap of the transmission area.

Since the organic insulating layer provided on the lower substrate has a smaller thickness in the transmissive region than in the reflective region, the transflective liquid crystal display having a double cell gap is realized. However, in order to form a transflective liquid crystal display device having a double cell gap, it is difficult to control the thickness of the organic insulating layer.

Therefore, there is a need for a structure capable of improving light efficiency in the reflection mode and the transmission mode while maintaining the cell gap of the transflective liquid crystal display device uniformly.

Accordingly, it is an object of the present invention to provide an upper substrate for improving display characteristics.

In addition, another object of the present invention is to provide a liquid crystal display device having the above upper substrate.                         

In addition, another object of the present invention is to provide a method suitable for producing the above upper substrate.

An upper substrate according to an aspect of the present invention is a substrate having a first region and a second region adjacent to the first region, a first insulating film provided in the first region of the substrate, the first insulating film and the first substrate of the substrate. A transparent electrode provided in two areas and a second insulating film provided on the transparent electrode corresponding to the second area.

According to another aspect of the present invention, a liquid crystal display includes a lower substrate, an upper substrate, and a liquid crystal layer interposed between the lower substrate and the upper substrate. The lower substrate includes a transmission electrode and a reflection electrode on the first substrate to define a reflection area and a transmission area.

The upper substrate may include a second substrate, a first insulating film provided in the transmissive region of the second substrate, a common electrode provided in the reflective region of the first insulating film and the second substrate, and the transmissive region. It includes a second insulating film provided in.

According to a method of manufacturing an upper substrate according to another aspect of the present invention, a first insulating film is formed in the first region of the substrate having a first region and a second region adjacent to the first region. Thereafter, a transparent electrode is formed in the first insulating layer and the second region of the substrate. Next, a second insulating film is formed on the transparent electrode corresponding to the second region.

The liquid crystal display device having the upper substrate may maintain a uniform cell gap and maintain the distance between the reflective electrode and the common electrode larger than the distance between the transmissive electrode and the common electrode. As a result, both the reflectance of the reflection region and the transmittance of the transmission region can be improved, thereby improving the display characteristics of the liquid crystal display device.

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

1 is a cross-sectional view showing in detail the upper substrate according to an embodiment of the present invention, Figure 2 is a plan view of the upper substrate shown in FIG.

1 and 2, an upper substrate 100 according to an embodiment of the present invention may include a color filter layer 120, a planarization layer 130, a first insulating layer 140, and a common electrode on a substrate 110. 150 and the second insulating film 160 are sequentially provided. The upper substrate 100 is divided into a first area A1 and a second area A2 adjacent to the first area A1.

The color filter layer 120 includes R (red), G (Green), and B (Blue) color pixels, and each of the R, G, and B color pixels includes the substrate 110 in the second area A2. The hole 121 exposing) is formed. The hole 121 is formed smaller than the second area A2. 1 illustrates a structure in which one hole 121 is formed in each of the R, G, and B color pixels. However, a plurality of holes may be formed in each of the R, G, and B color pixels.

The planarization layer 130 is formed on the substrate 110 exposed by the color filter layer 120 and the hole 121. Accordingly, the planarization layer 130 removes a step between the color filter layer 120 and the substrate 110 exposed by the hole 121.                     

Thereafter, the first insulating layer 140 is formed on the planarization layer 130 corresponding to the first region A1. Next, the common electrode 150 is formed to have a uniform thickness on the planarization layer 130 corresponding to the first insulating layer 140 and the second region A2.

The second insulating layer 160 is formed on the common electrode 150 corresponding to the second region A2. In this case, the first thickness t1 of the second insulating layer 160 is the same as the second thickness t2 of the first insulating layer 140. Therefore, the upper substrate 100 has a uniform thickness as a whole.

3 is a cross-sectional view showing an upper substrate according to another embodiment of the present invention. 3, the same reference numerals are given to the same components as those shown in FIG. 1, and description thereof will be omitted.

Referring to FIG. 3, the upper substrate 180 according to another exemplary embodiment of the present invention may include a color filter layer 170, a first insulating layer 140, a common electrode 150, and a second insulating layer 160 on the substrate 110. ) Are sequentially provided. The upper substrate 100 is divided into a first area A1 and a second area A2 adjacent to the first area A1.

The color filter layer 170 is formed of R (red), G (Green), and B (Blue) color pixels. The first insulating layer 140 is formed on the color filter layer 170 corresponding to the first region A1. Thereafter, the common electrode 150 is formed to have a uniform thickness on the color filter layer 170 corresponding to the first insulating layer 140 and the second region A2.

Next, the second insulating layer 160 is formed on the common electrode 150 corresponding to the second region A2. In this case, the first thickness t1 of the second insulating layer 160 is the same as the second thickness t2 of the first insulating layer 140. Therefore, the upper substrate 100 has a uniform thickness as a whole.

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

Referring to FIG. 4, the transflective liquid crystal display device 400 according to another exemplary embodiment of the present invention may include a lower substrate 200, an upper substrate 100, and the lower substrate facing the lower substrate 200. The liquid crystal layer 300 is interposed between the 200 and the upper substrate 100.

The lower substrate 200 includes a gate insulating film 220, an organic insulating film 230, a transmissive electrode 140, and a reflective electrode 150 on the first substrate 210. A plurality of TFTs (not shown) is provided on the first substrate 210, and the gate insulating layer 220 is formed on the first substrate 210 as one of the components forming the TFT. In addition, the organic insulating layer 230 is provided on the TFT and the gate insulating layer 220 and is made of acrylic resin, which is a photosensitive insulating material.

A plurality of irregularities 233 are provided on the surface of the organic insulating layer 230. That is, the organic insulating layer 230 has a plurality of concave-convex portions 233 formed of a relatively thick convex portion 233a and a relatively thin concave portion 233b.

On the organic insulating layer 230, the transmissive electrode 240 made of indium tin oxide (ITO) or indium zinc oxide (IZO), which is a transparent conductive material, is formed to have a uniform thickness. do.

Thereafter, the reflective electrode 250 having a transmission window 251 for exposing a portion of the transmission electrode 240 over the transmission electrode 240 is formed to have a uniform thickness. In this case, the reflective electrode 250 may have a single layer made of aluminum-neodymium (AlNd) or a double layer structure in which aluminum-neodymium (AlNd) and molybdenum tungsten (MoW) are sequentially stacked.

Although not shown, a contact hole (not shown) for exposing the drain electrode of the TFT may be formed in the organic insulating layer 230. When the contact hole is formed in the organic insulating layer 230, the transmission electrode 240 and the reflection electrode 250 are electrically connected to the drain electrode of the TFT through the contact hole.

Accordingly, the transflective liquid crystal display device 400 includes a reflection area RA provided with the reflective electrode 250 and a transmission area TA formed with the transmission window 251.

In the reflective area RA, the external light L1 incident through the upper substrate 100 is reflected by the reflective electrode 250 and is emitted to the outside through the upper substrate 100 to display an image. . Meanwhile, in the transmission area TA, an image is displayed by emitting the internal light L2 incident from the light source unit (not shown) disposed on the rear surface of the lower substrate 200 through the transmission window 251.

Meanwhile, the upper substrate 100 sequentially orders the color filter layer 120, the planarization layer 130, the first insulating layer 140, the common electrode 150, and the second insulating layer 160 on the second substrate 110. It is equipped with.                     

The color filter layer 120 is formed of R (red), G (Green), and B (Blue) color pixels, and each of the R, G, and B color pixels is formed in the reflective region RA. Has a hole 121 exposing 110. As described above, the external light L1 used in the reflective area RA passes through the color filter layer 120 twice, but the internal light L2 used in the transmission area TA passes through the color filter layer. Pass 120 once.

In this case, the hole 121 partially removes the color filter layer 120 formed in the reflective region RA. Therefore, the probability that the external light L1 can pass through the color filter layer 120 can be reduced, thereby compensating for the difference in color reproducibility between the reflection area RA and the transmission area TA. Can be.

The planarization layer 130 is formed on the second substrate 110 exposed by the color filter layer 120 and the hole 121. Therefore, the planarization layer 130 removes a step formed between the color filter layer 120 and the second substrate 110 exposed by the hole 121.

Thereafter, the first insulating layer 140 is formed on the planarization layer 130 corresponding to the transmission area TA. Next, the common electrode 150 is formed to have a uniform thickness on the first insulating layer 140 and the planarization layer 130 corresponding to the second region.

The second insulating layer 160 is formed on the common electrode 150 corresponding to the reflective region RA. In this case, the first thickness t1 of the second insulating layer 160 is the same as the second thickness t2 of the first insulating layer 140. Therefore, the thickness of the upper substrate 100 is uniform throughout.                     

Therefore, the first cell gap d1 in the reflection area RA and the second cell gap d2 in the transmission area TA may be substantially the same. As a result, the transflective liquid crystal display 400 may have a uniform cell gap.

On the other hand, in the reflective region RA, the first distance D1 between the reflective electrode 250 and the common electrode 150 is the transmissive electrode 240 and the common electrode in the transmissive area TA. Greater than the second distance D2 from 150.

5 is a graph showing changes in transmittance and reflectance according to the reflection voltage and the transmission voltage. In FIG. 5, the first graph TG shows a change in transmittance, and the second graph RG shows a change in reflectance.

4 and 5, when the voltage applied to the common electrode 230 is the same in the transmission area TA and the reflection area RA, the transflective liquid crystal display 400 may transmit the transmission area TA. The maximum transmittance (about 40%) is applied when about 4.2V is applied to the liquid crystal layer 300 provided in the). On the other hand, when the voltage applied to the common electrode 230 is the same in the transmission area TA and the reflection area RA, the transflective liquid crystal display 400 is a liquid crystal provided in the reflection area RA. The maximum reflectance (about 38%) is shown when about 2.6V is applied to layer 300.

As described above, since the transmission voltage showing the maximum transmittance and the reflection voltage showing the maximum reflectance are different from each other, different voltages are applied to the liquid crystal layer 300 provided in the reflection area RA and the liquid crystal layer provided in the transmission area TA. It is preferable to apply. That is, about 4.2 V showing the maximum transmittance is applied to the liquid crystal layer provided in the transmission area TA, and 2.6 V smaller than 4.2 V is applied to the liquid crystal layer provided in the reflection area RA. Accordingly, the transmissivity and the reflectance of the transflective liquid crystal display device 400 can be ensured to the maximum.

In general, the capacitance C satisfies the following equation.

In Equation 1, 'ε' is a permittivity, 'd' is an inter-electrode distance, and 'A' is an area of each electrode.

As shown in Equation 1, the capacitance C is proportional to the distance d. That is, as the distance d increases, the capacitance C decreases, and when the distance d decreases, the capacitance C increases in inverse proportion thereto.

In addition, the capacitance C satisfies the following expression (2).

In Equation 2, 'Q' is the amount of charge and 'V' is the voltage.

As shown in equation (2), the capacitance (C) is inversely proportional to the voltage (V). That is, as the capacitance C increases, the voltage V decreases in inverse proportion thereto. When the capacitance C decreases, the voltage V increases in inverse proportion thereto.                     

Referring to FIG. 4 again, in the reflective region RA, the first distance D1 between the reflective electrode 250 and the common electrode 150 may correspond to the transmissive electrode 240 in the transmissive area TA. It is larger than the second distance D2 from the common electrode 150.

According to Equations 1 and 2, the reflection area RA is inversely proportional to the first distance D1 in the reflection area RA being greater than the second distance D2 in the transmission area TA. ), The reflection voltage applied to the liquid crystal layer 300 decreases from the transmission voltage applied to the liquid crystal layer 300 in the transmission area TA.

As shown in Equation 1, the dielectric constant epsilon also serves as a factor for determining the capacitance C. Therefore, the reflection voltage may be reduced from the transmission voltage by adjusting the dielectric constant of the second insulating layer 160 interposed between the reflective electrode 250 and the common electrode 150. That is, the second insulating layer 160 may have a different dielectric constant from that of the liquid crystal layer 300 to change the magnitude of the reflected voltage.

6A through 6E are cross-sectional views illustrating an embodiment of a manufacturing process of the upper substrate illustrated in FIG. 1.

Referring to FIG. 6A, a color filter layer 120 including R (red), G (Green), and B (Blue) color pixels is formed on the substrate 110. Holes 121 are formed in the R, G, and B color pixels to expose the substrate 110. Thus, a part of the R, G, and B color pixels formed in the second area A2 are removed.

As shown in FIG. 6B, a planarization layer 130 is formed on the substrate 110 exposed by the color filter layer 120 and the hole 121. Accordingly, the planarization layer 130 removes a step generated between the color filter layer 120 and the substrate 110 exposed by the hole 121.

Referring to FIG. 6C, after forming a positive photoresist (not shown) on the planarization layer 130 as a whole, a first mask 101 for patterning the positive photoresist is disposed on the positive photoresist. Here, the first mask 101 is a mask patterned to have an opening 101a corresponding to the second area A2.

Next, the positive photoresist is exposed while the first mask 101 is disposed, and after the first mask 101 is removed, the exposed portion of the positive photoresist is removed through an etching process. Thus, the first insulating layer 140 corresponding to the first region A1 is formed on the planarization layer 130.

As illustrated in FIG. 6D, the common electrode 150 is formed to have a uniform thickness on the planarization layer 130 corresponding to the first insulating layer 140 and the second region. The common electrode 150 is made of ITO or IZO.

Referring to FIG. 6E, after forming a negative photoresist (not shown) on the common electrode 150 as a whole, the first mask 101 for patterning the negative photoresist is formed on the negative photoresist. .

Next, the negative photoresist is exposed while the first mask 101 is disposed, the first mask 101 is removed, and then the exposed portion of the negative photoresist is removed through an etching process. As a result, the second insulating layer 160 corresponding to the second region A2 is formed on the common electrode 150.

As such, the first insulating layer 140 is made of a positive photoresist, whereas the second insulating layer 160 is made of a negative photoresist, so that the first insulating layer 140 and the second insulating layer 160 Patterning may be performed using a mask. Therefore, manufacturing cost for manufacturing the upper substrate 100 can be reduced, and the number of manufacturing processes can be reduced.

7A to 7C are cross-sectional views illustrating another example of a manufacturing process of the upper substrate illustrated in FIG. 1.

Referring to FIG. 7A, a negative photoresist (not shown) is entirely formed on the planarization layer 130 in a state where the color filter layer 120 and the planarization layer 130 are formed on the substrate 110. Thereafter, a second mask 103 for patterning the negative photoresist is disposed on the negative photoresist. Here, the second mask 103 is a mask patterned to have an opening 103a corresponding to the first area A1.

Next, the negative photoresist is exposed while the second mask 103 is disposed, the second mask 103 is removed, and then the exposed portion of the negative photoresist is removed through an etching process. Thus, the first insulating layer 140 corresponding to the first region A1 is formed on the planarization layer 130.

As shown in FIG. 7B, the common electrode 150 is formed to have a uniform thickness on the planarization layer 130 corresponding to the first insulating layer 140 and the second region.

Referring to FIG. 7C, after forming a positive photoresist (not shown) on the common electrode 150 as a whole, the second mask 103 for patterning the positive photoresist is disposed on the positive photoresist. do.

Next, the positive photoresist is exposed while the second mask 103 is disposed, the second mask 103 is removed, and then the exposed portion of the positive photoresist is removed through an etching process. As a result, the second insulating layer 160 corresponding to the second region A2 is formed on the common electrode 150.

As such, the first insulating layer 140 is made of a negative photoresist, whereas the second insulating layer 160 is made of a positive photoresist, so that the first insulating layer 140 and the second insulating layer 160 Patterning may be performed using a mask. Therefore, manufacturing cost for manufacturing the upper substrate 100 can be reduced, and the number of manufacturing processes can be reduced.

Although not shown in the drawings, each of the first and second insulating layers 140 and 160 may be formed of a positive photoresist. In addition, each of the first and second insulating layers 140 and 160 may be formed of a negative photoresist. In this case, in addition to the mask for patterning the first insulating layer 140, a mask for patterning the second insulating layer 160 is further provided.

According to such an upper substrate, a liquid crystal display device having the same, and a method of manufacturing the same, the upper substrate includes a first insulating film, a first insulating film, and a common electrode provided on a substrate corresponding to the reflective region. And a second insulating film stacked on the common electrode corresponding to the reflective region.

Therefore, the liquid crystal display may maintain a uniform cell gap and maintain the distance between the reflective electrode and the common electrode larger than the distance between the transmissive electrode and the common electrode. As a result, it is possible to improve both the reflectance of the reflective region and the transmittance of the transmissive region, thereby improving the display characteristics of the liquid crystal display device.

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 (12)

A substrate having a transmissive region defined by a transmissive electrode and a reflective region adjacent to said transmissive region and defined by a reflective electrode; A first insulating film provided in the transmission region of the substrate; A transparent electrode provided in the reflective region of the first insulating film and the substrate; And And a second insulating film provided on the transparent electrode corresponding to the reflective region. The upper part of claim 1, further comprising a color filter layer interposed between the substrate and the first insulating layer in the transmission region and interposed between the substrate and the transparent electrode in the reflection region. Board. The upper substrate of claim 2, wherein at least one hole is formed in the color filter layer to expose the substrate in the reflective region. 4. The upper substrate of claim 3, further comprising a planarization film disposed on the color filter layer to remove a step between the color filter layer and the substrate exposed by the hole. A lower substrate having a transmissive electrode and a reflective electrode on the first substrate, the lower substrate defining a reflective region and a transmissive region; A second substrate, a first insulating film provided in the transmissive region of the second substrate, a common electrode provided in the reflective region of the first insulating film and the second substrate, and a second provided on the common electrode corresponding to the reflective region. An upper substrate including an insulating film; And And a liquid crystal layer interposed between the lower substrate and the upper substrate. The liquid crystal display of claim 5, wherein a transmissive window is formed in the reflective electrode to expose a portion of the transmissive electrode, and the transmissive window is formed on the transmissive electrode. The method of claim 6, wherein the lower substrate further comprises an organic insulating film interposed between the first substrate and the transmission electrode, A surface of the organic insulating film has a concave-convex structure. 6. The liquid crystal display device according to claim 5, wherein the second insulating film has a dielectric constant different from that of the liquid crystal layer. Forming a first insulating film in the transmissive region of the substrate having a transmissive region defined by the transmissive electrode and a reflecting region adjacent the transmissive region and defined by the reflective electrode; Forming a transparent electrode on the first insulating layer and the reflective region of the substrate; And And forming a second insulating film on the transparent electrode corresponding to the reflective region. 10. The method of claim 9, wherein the first and second insulating layers are made of any one of a positive photoresist and a negative photoresist. The method of claim 10, wherein the first and second insulating layers are formed of different photoresists. The method of claim 9, before the forming of the first insulating film, Forming a color filter layer on the substrate; Forming at least one hole in the color filter layer to expose the substrate in the reflective region; And And forming a planarization film on the color filter layer to remove the step difference between the color filter layer and the substrate.

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