KR101344259B1 - Liquid crystal display panel and method for fabricating the same - Google Patents

Abstract

The present invention relates to a liquid crystal display panel and a method for manufacturing the same, wherein the liquid crystal display panel according to the present invention comprises a lower array substrate and an upper array substrate; A liquid crystal layer interposed between the first surface of the lower array substrate and the first surface of the upper array substrate; A first polarizing plate formed on a second surface of the lower array substrate; A reflection suppression layer formed on a second surface of the upper array substrate; And a second polarizing plate formed on the reflection suppression layer of the upper array substrate. By adding a material layer having a different refractive index on the upper array substrate, the reflectance of the liquid crystal display panel due to external light can be reduced.

 Reflection suppression layer, external light, refractive index, liquid crystal display panel, polarizing plate

Description

Liquid crystal display panel and its manufacturing method {LIQUID CRYSTAL DISPLAY PANEL AND METHOD FOR FABRICATING THE SAME}

1 is an exploded perspective view schematically showing a liquid crystal display panel according to the prior art.

2 is a cross-sectional view schematically showing a liquid crystal display panel according to the prior art.

Figure 3 is an exploded perspective view schematically showing a liquid crystal display panel according to the present invention.

4 is a cross-sectional view schematically showing a liquid crystal display panel according to the present invention.

5A to 5D are cross-sectional views schematically illustrating a process of manufacturing a liquid crystal display panel according to the present invention.

6 is a graph showing a change in reflectivity of the substrate surface according to the thickness of the reflection suppression layer in the liquid crystal display panel according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS -

101: lower substrate 103: gate line

103a: gate electrode 105: gate insulating film

107: active pattern 109: data line

109a: source electrode 109b: drain electrode

111 protective film 113 pixel electrode

121: upper substrate 123: black matrix

125: color filter layer 127: common electrode

129: reflection suppression layer 131: first polarizing plate

133: second polarizing plate 141: liquid crystal layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel, and more particularly, to a liquid crystal display panel and a method of manufacturing the same, which can reduce the reflectance of the liquid crystal display panel due to external light by adding a material layer having a different refractive index on a substrate.

In general, a liquid crystal display device (LCD) displays an image by adjusting the light transmittance of the liquid crystal using an electric field.

To this end, the liquid crystal display device includes a liquid crystal display panel in which liquid crystal cells are arranged in a matrix, and a driving circuit for driving the liquid crystal display panel.

The liquid crystal display panel includes pixel electrodes for applying an electric field to each of the liquid crystal cells and a reference electrode, that is, a common electrode.

In general, the pixel electrode is formed for each liquid crystal cell on the lower substrate, while the common electrode is integrally formed on the entire surface of the upper substrate. Each of the pixel electrodes is connected to a thin film transistor (hereinafter referred to as TFT) which is used as a switching element.

The pixel electrode is driven together with the common electrode according to the data signal supplied through the TFT.

In this regard, the liquid crystal display panel of the related art will be described with reference to FIGS. 1 and 2 as follows.

1 is an exploded perspective view showing a liquid crystal display panel according to the prior art.

2 is a schematic cross-sectional view of a liquid crystal display panel according to the related art.

1 and 2, a liquid crystal display panel according to the related art includes a lower array substrate 11 and an upper array substrate 21 bonded to each other with a liquid crystal 31 interposed therebetween, and the lower array substrate ( 11) and upper and lower polarizing plates 43 and 41 are provided on the surface of the upper array substrate 21, respectively.

Here, the liquid crystal 31 is rotated in response to an electric field applied to the liquid crystal 31 to adjust the amount of light transmitted through the lower array substrate 11.

In addition, a color filter 25, a common electrode 27, and an upper alignment layer (not shown) are formed on the rear surface of the upper array substrate 21.

In addition, the color filter 25 includes color filters of red (R), green (G), and blue (B) colors to allow color display by transmitting light of a specific wavelength band.

In addition, a black matrix 23 is formed between the adjacent color filters 25 to prevent the decrease in contrast by absorbing light incident from the adjacent cells.

On the other hand, the data line 19 and the gate line 13 are formed to cross each other with a gate insulating film (not shown) on the front surface of the lower array substrate 11, and a TFT (T) is formed at the intersection thereof. It is.

The TFT T may include a gate electrode (not shown) connected to the gate line 13, a source electrode (not shown) connected to the data line 19, an active layer (not shown), and an ohmic contact layer (not shown). And a drain electrode (not shown) facing the source electrode (not shown) with a channel portion interposed therebetween.

In addition, the TFT T is connected to the pixel electrode 15 through a contact hole penetrating a protective film (not shown).

The TFT T selectively supplies the data signal from the data line 19 to the pixel electrode 15 in response to the gate signal from the gate line 13.

The pixel electrode 15 is positioned in a cell region divided by the data line 19 and the gate line 13 and is made of a transparent conductive material having high light transmittance.

The pixel electrode 15 generates a potential difference from the common electrode 27 by a data signal supplied via a drain electrode (not shown).

This potential difference causes the liquid crystal to be rotated by the dielectric anisotropy of the liquid crystal positioned between the lower array substrate 11 and the upper array substrate 21.

Accordingly, light supplied from the light source via the pixel electrode 15 is transmitted toward the upper array substrate 21.

However, when external light is incident on the inside of the liquid crystal panel through the upper array substrate, since the smooth glass surface of the upper array substrate is exposed to the outside, the external light is reflected by about 4% or more from the glass surface, so that the visibility of the liquid crystal panel is improved. The problem of deterioration occurs.

Accordingly, the present invention has been made to solve the problems of the prior art, an object of the present invention is to reduce the reflectance of the liquid crystal display panel by external light by adding a material layer having a different refractive index on the surface of the upper array substrate liquid crystal panel It is to provide a liquid crystal display panel and a method of manufacturing the same that can improve the visibility.

According to an exemplary embodiment of the present invention, a liquid crystal display panel includes a lower array substrate and an upper array substrate; A liquid crystal layer interposed between the first surface of the lower array substrate and the first surface of the upper array substrate; A first polarizing plate formed on a second surface of the lower array substrate; A reflection suppression layer formed on a second surface of the upper array substrate; And a second polarizing plate formed on the reflection suppression layer of the upper array substrate.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display panel, including: providing a lower array substrate and an upper array substrate; Forming a first polarizing plate on a second surface of the lower array substrate; Forming a reflection suppression layer on a second surface of the upper array substrate; Forming a second polarizing plate on the reflection suppression layer of the upper array substrate; And forming a liquid crystal layer between the first surface of the lower array substrate and the first surface of the upper array substrate.

Hereinafter, a liquid crystal display panel and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

3 is an exploded perspective view schematically showing a liquid crystal display panel according to the present invention.

4 is a schematic cross-sectional view of a liquid crystal display panel according to the present invention.

3 and 4, the liquid crystal display panel according to the present invention includes a lower array substrate 101 and an upper array substrate 121 bonded together with the liquid crystal 141 interposed therebetween.

Here, the lower array substrate 101 is formed such that the data line 109 and the gate line 103 which are insulated with a gate insulating film (not shown; 105 in FIG. 5A) intersect with each other. A TFT (T) is formed, and a pixel electrode 113 is connected to the TFT (T).

In addition, the TFT T includes a gate electrode (not shown) connected to the gate line 103, a source electrode (not shown) connected to the data line 109, an active layer (not shown), and an ohmic contact layer (not shown). It is composed of a drain electrode (not shown) facing the source electrode (not shown) with a channel portion including a).

Here, the TFT (T) is connected to the pixel electrode 113 through a contact hole penetrating a protective film (not shown).

The TFT T selectively supplies the data signal from the data line to the pixel electrode 113 in response to the gate signal from the gate line 103.

The pixel electrode 113 is positioned in a cell region divided by the data line 109 and the gate line 103 and is made of a transparent conductive material such as indium tin oxide (ITO) having high light transmittance.

The pixel electrode 113 generates a potential difference from the common electrode 127 by a data signal supplied through a drain electrode (not shown). Due to this potential difference, the liquid crystal 141 positioned between the lower array substrate 101 and the upper array substrate 121 is rotated by the dielectric anisotropy.

Accordingly, light supplied from the light source via the pixel electrode 113 is transmitted toward the upper array substrate 121.

Meanwhile, the upper array substrate 121 includes a color filter 125 formed between the black matrix 123 and the black matrix 123 and a common electrode formed on a substrate including the black matrix 123 and the color filter 127. 127 is provided.

In addition, a reflection suppression layer 129 is formed on the entire surface of the upper array substrate 121 to suppress reflection by external light.

The material for forming the reflection suppression layer 129 may be a material having a refractive index of about 1.6 to 1.7, for example, Al ₂ O _3. Use materials such as

In addition, the A ₂ O ₃ thickness is formed in the range of 0.01 μm to 2.0 μm, most preferably in the range of 0.5 to 0.8 μm.

In addition, the black matrix 123 formed between the color filters 125 of the adjacent color absorbs the light incident from the adjacent cells, thereby preventing the lowering of the contrast.

In addition, the color filter 125 includes color filters of red (R), green (G), and blue (B) colors to allow color display by transmitting light of a specific wavelength band.

On the other hand, the first polarizing plate 141 and the second polarizing plate 143 are provided on the front of the lower array substrate 101 and the upper array substrate 121, respectively.

In addition, the reflection suppression layer 129 is Al ₂ O ₃ It is made of a material, the light due to the difference in the refractive index with the glass material of the upper array substrate can interfere with the visibility due to the reflection of the external light can be prevented.

Particularly, when the refractive indices n1 and n2 of the first medium and the second medium are described, the reflectances R at different media interfaces are as follows.

Here, the first medium is glass, the refractive index is 1.52, the second medium is Al ₂ O ₃ As a substance this Al ₂ O ₃ The refractive index of the material is assumed to be 1.65.

R = [(n1-n2) / (n1 + n2)] ²

Therefore, when the substrate surface is a glass surface, the reflection of external light on the glass surface is calculated as follows.

R = [(1.52-1.65) / (1.52 + 1.65)] ² = 0.016

As described above, when the refractive index of the reflection suppression layer is assumed to be 1.65, external light incident on the liquid crystal display panel reflects only about 1.6%.

As such, Al ₂ O ₃ has a different refractive index than that of the glass surface of the substrate. Since the material layer is formed on the surface of the glass substrate, the reflectance of the external light can be reduced due to the difference in refractive index, thereby preventing the visibility of the external light from deteriorating.

Meanwhile, a method of manufacturing a liquid crystal display panel according to the present invention will be described with reference to FIGS. 5A to 5D.

5A to 5D are cross-sectional views schematically illustrating a process of manufacturing a liquid crystal display panel according to the present invention.

Referring to FIG. 5A, a metal material is deposited on a lower array substrate 101 made of transparent glass, and then selectively patterned by a mask process to protrude from the gate line 103 and the gate line 109. The gate electrode 103a is formed.

In this case, Al-based metals such as Al and Al alloys, Ag-based metals such as Ag and Ag alloys, Mo-based metals such as Mo and Mo alloys, Cr, Ti, Ta and the like.

In addition, they may include two membranes of different material properties, that is, the lower layer and the upper layer thereon. The upper layer is made of a low resistivity metal such as an Al-based metal or an Ag-based metal so as to reduce the signal delay or voltage drop of the gate line.

On the other hand, the lower layer may be made of other materials, especially materials having excellent physical, chemical and electrical contact properties with indium tin oxide (ITO) or indium zinc oxide (IZO), for example, Ti, Ta, Cr, Mo-based metals, or the like. Or an example of the combination of the lower layer and the upper layer is a Cr / Al-Nd alloy.

Next, a gate insulating film 105 made of silicon nitride (SiNx) or the like is formed on the lower array substrate 101 including the gate line 103 and the gate electrode 103a.

Subsequently, a semiconductor layer (not shown) made of a hydrogenated amorphous silicon layer or the like is formed on the gate insulating layer 105.

Next, an ohmic contact layer (not shown) made of a material such as n + hydrogenated amorphous silicon in which silicide or n-type impurities are heavily doped is formed on the semiconductor layer (not shown).

Subsequently, the ohmic contact layer and the semiconductor layer are selectively patterned by a mask process to form an active pattern 107 and an ohmic contact layer pattern (not shown).

Thereafter, a metal material for a data line is deposited on the lower array substrate 101 including the active pattern 107 and the ohmic contact layer pattern (not shown), and then patterned by a mask process to selectively pattern the data line. And a source electrode 109a protruding from the data line 109 and a drain electrode 109b spaced apart from the source electrode 109a by a predetermined interval, respectively.

In this case, the data line 109 is formed to cross the gate line 103, and the source electrode 109a and the drain electrode 109b together with the gate electrode 103a under the thin film as a switching element. The transistor T is constituted.

In addition, a channel of the thin film transistor T is formed in the active pattern 107 between the source electrode 109a and the drain electrode 109b.

The metal material for forming the data line 109 may be formed of an Al-based metal, an Ag-based metal, a Mo-based metal, Cr, Ti, Ta, or the like, and may be formed in multiple layers.

Next, referring to FIG. 5B, an organic material having excellent planarization characteristics and photosensitivity, or an insulating material having low dielectric constant, on the lower array substrate 101 including the data line 109 and the drain electrode 109b; Alternatively, a protective film 111 made of silicon nitride or the like, which is an inorganic material, is formed.

Subsequently, the protective film 111 is selectively patterned by a mask process to form a contact hole (not shown) that exposes a part of the drain electrode 109b in the protective film 111.

Next, a metal layer (not shown) made of a transparent conductive material such as ITO or IZO is deposited on the passivation layer 111 including the contact hole (not shown), and then selectively removed by the mask process to form a pixel electrode ( 113).

In this case, when a data voltage is applied, the pixel electrode 113 generates an electric field together with the common electrode 127 of another upper array substrate 121 to which a common voltage is applied, thereby creating a common electric field with the pixel electrode 113. The liquid crystal molecules of the liquid crystal layer 141 between the electrodes 127 are arranged.

Meanwhile, referring to FIG. 5C, a black matrix 123 is formed on the upper array substrate 121 to define a plurality of unit cell regions with an opaque metal material such as Cr.

In this case, the black matrix 123 absorbs light incident from an adjacent cell to prevent a decrease in contrast.

Next, a color filter layer 125 of red (R), green (G), and blue (B) color is formed on the surface of the upper array substrate 121 between the black matrices 123.

In this case, the color filter layer 125 may include color filters of red (R), green (G), and blue (B) colors to transmit light of a specific wavelength band, thereby enabling color display.

Subsequently, a common electrode 127 made of a transparent conductive material is formed on the upper array substrate 121 including the color filter layer 125 and the black matrix 123.

Here, although the case in which the common electrode 127 is formed on the upper array substrate has been described, it may be formed on the lower array substrate 101 according to the driving mode of the liquid crystal display panel.

Next, a reflection suppression layer 129 is formed on the front surface of the upper array substrate 121 to suppress reflection by external light.

In this case, a material having a refractive index of 1.6 to 1.7, for example, A ₂ O ₃ or another insulating material may be used as the material used as the reflection suppression layer 129.

In addition, the A ₂ O ₃ thickness is formed in the range of 0.01 μm to 2.0 μm, most preferably in the range of 0.5 to 0.8 μm.

The reflection suppression layer 129 serves to prevent deterioration of visibility due to reflection of external light because light causes interference due to a difference in refractive index with the glass material of the upper array substrate 121 described above.

Subsequently, a first polarizing plate 131 and a second polarizing plate 133 are formed on the front surfaces of the lower array substrate 101 and the upper array substrate 121 which have been subjected to the array forming process.

After the array process is performed on the lower array substrate 101 and the upper array substrate 121, a liquid crystal layer 141 is formed between the lower array substrate 101 and the upper array substrate 121 to manufacture the liquid crystal display panel. Complete the process.

On the other hand, the reflectance by the external light of the liquid crystal display panel configured as described above with reference to Figure 6 as follows.

6 is a graph showing a surface reflectance change according to the thickness of the reflection suppression layer in the liquid crystal display panel according to the present invention.

Referring to Figure 6, A ₂ O ₃ is used as a reflection preventative layer, A ₂ O ₃ The results investigating the reflectivity in the thickness range 0.01μm to 2.0 μm, the reflectance was about 1.5 to 2.0%.

In addition, the reflectance by external light on the surface of the liquid crystal display panel was the smallest in the range of about 1.5% in the A ₂ O ₃ thickness range of 0.5 to 0.8 μm.

Therefore, when A ₂ O ₃ is used as the reflection suppression layer, it can be seen that the reflectance is reduced in the range of A ₂ O ₃ layer 0.5 to 0.8 μm.

As described above, according to the liquid crystal display panel and the manufacturing method thereof according to the present invention has the following effects.

The liquid crystal display panel according to the present invention and a method of manufacturing the same are added to the difference in refractive index with the glass material of the upper array substrate by adding a reflection suppression layer composed of a material such as A ₂ O ₃ having a different refractive index from the glass surface on the surface of the upper array substrate. As a result, light causes interference and suppresses reflection by external light, thereby preventing visibility from being lowered due to reflection of external light.

On the other hand, while described above with reference to a preferred embodiment of the present invention, those skilled in the art various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below And can be changed.

Claims (14)

A lower array substrate and an upper array substrate; A liquid crystal layer interposed between the first surface of the lower array substrate and the first surface of the upper array substrate; A first polarizing plate formed on a second surface of the lower array substrate; A reflection suppression layer formed on a second surface of the upper array substrate, the reflection suppression layer having a refractive index of 1.6 to 1.7 and different from the refractive index of the upper array substrate; And And a second polarizing plate formed on the reflection suppression layer of the upper array substrate. The reflection suppression layer is a liquid crystal display panel comprising A ₂ O ₃ . delete delete The liquid crystal display panel of claim 1, wherein the A ₂ O ₃ has a thickness of 0.01 μm to 2.0 μm. The liquid crystal display panel of claim 1, wherein the material forming the reflection suppression layer is formed by combining one or more materials. The liquid crystal display of claim 1, wherein a plurality of gate lines and data lines arranged on the lower array substrate to intersect with each other, a thin film transistor provided at a point where they intersect, and a pixel electrode connected to the thin film transistor. Display panel. The liquid crystal display panel according to claim 1, wherein a color filter layer formed between the black matrix and the adjacent black matrix and a common electrode formed on the black matrix and the color filter layer are provided on the upper array substrate. Providing a lower array substrate and an upper array substrate; Forming a first polarizing plate on a second surface of the lower array substrate; Forming a reflection suppression layer on the second surface of the upper array substrate that is different from the refractive index of the upper array substrate and has a refractive index of 1.6 to 1.7; Forming a second polarizing plate on the reflection suppression layer of the upper array substrate; And And forming a liquid crystal layer between the first surface of the lower array substrate and the first surface of the upper array substrate. The material forming the reflection suppression layer comprises a liquid crystal display panel comprising A ₂ O ₃ . delete delete The method of claim 8, wherein the A ₂ O ₃ has a thickness of 0.01 μm to 2.0 μm. The method of claim 8, wherein the material forming the reflection suppression layer comprises one or more materials combined. 10. The method of claim 8, further comprising: forming a plurality of gate lines and data lines arranged on the lower array substrate to cross each other, a thin film transistor provided at a point where they cross, and a pixel electrode connected to the thin film transistor. Liquid crystal display panel manufacturing method characterized in that. The liquid crystal display of claim 8, further comprising forming a color filter layer formed between the black matrix and the adjacent black matrix on the upper array substrate, and a common electrode formed on the black matrix and the color filter layer. Display panel manufacturing method.

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