KR101157290B1 - Liquid crystal display and method for fabricating the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of switching between a wide viewing angle mode and a narrow viewing angle mode, and a liquid crystal display device capable of switching between a wide viewing angle mode and a narrow viewing angle mode according to the present invention includes an array substrate and a color filter substrate. A first thin film transistor and a second thin film transistor formed on the array substrate; A first pixel electrode connected to the first thin film transistor and a second pixel electrode connected to the second thin film transistor; A black matrix, a color filter layer, and a common electrode formed on the color filter substrate; And a liquid crystal layer sandwiched between the array substrate and the color filter substrate. According to the present invention, there is provided a method of manufacturing a liquid crystal display device capable of switching between a wide viewing angle mode and a narrow viewing angle mode, ; Forming a first thin film transistor and a second thin film transistor on the array substrate; Connecting a first pixel electrode to the first thin film transistor and forming a second pixel electrode in the second thin film transistor; Forming a black matrix, a color filter layer, and a common electrode on the color filter substrate; And interposing a liquid crystal layer between the array substrate and the color filter substrate.

 Wide viewing angle, narrow viewing angle, 2-domain, gray inversion

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device capable of switching modes between a wide viewing angle and a narrow viewing angle,

1 is a cross-sectional view schematically illustrating a liquid crystal display according to a related art;

2 is a cross-sectional view of a liquid crystal display device capable of switching modes between a wide viewing angle and a narrow viewing angle according to the present invention.

FIG. 3 is a diagram illustrating a liquid crystal display device capable of switching modes between a wide viewing angle and a narrow viewing angle according to an embodiment of the present invention, in which the liquid crystal alignment in one pixel is formed in a two- b) is a schematic view showing the liquid crystal alignment direction of each sub pixel in one pixel.

FIG. 4 is a cross-sectional view of a liquid crystal display device in which a wide viewing angle and a narrow viewing angle according to an embodiment of the present invention can be switched, when a wide viewing angle is realized. FIG.

5 is a cross-sectional view of a liquid crystal display device when a narrow viewing angle is realized in a liquid crystal display device capable of switching between a wide viewing angle and a narrow viewing angle according to the present invention.

[0001] The present invention relates to a liquid crystal display panel, and more particularly, to a liquid crystal display (LCD) panel, which includes a first thin film transistor (TFT) 111, an array substrate 113, a gate electrode 115, a gate insulating layer 117,

120: second thin film transistor 121: source electrode

123: first insulating film 125: first pixel electrode

127: second insulating film 141: color filter substrate

143: black matrix 145: color filter layer

147: common electrode 151: liquid crystal layer

161: first polarizing plate 163: second polarizing plate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a liquid crystal display device capable of switching between a wide viewing angle mode and a narrow viewing angle mode.

Description of the Related Art Flat panel display devices of high image quality and low power consumption are mainly used as liquid crystal display devices.

A typical liquid crystal display device of the flat panel display device has a structure in which a liquid crystal is injected between two substrates and a light transmittance is controlled by controlling the intensity of an electric field applied to an electrode formed on a substrate surface. Video telephones, TVs, and various portable electronic products.

In recent years, as users' demands have become increasingly diverse, various liquid crystal modes capable of enlarging the liquid crystal display device, providing high definition, and viewing angle have been proposed.

As a typical example of a liquid crystal display device having a wide viewing angle characteristic, there is a liquid crystal display device of a lateral electric field driving type and a vertical alignment (VA) type liquid crystal display device to which a compensation film is applied.

In the transverse electric field driving type liquid crystal display device in which the pixel electrode and the common electrode are formed on the same substrate, a horizontal electric field is formed between the pixel electrode and the common electrode on the substrate surface when the pixel is turned on, The major axes of the liquid crystal molecules operate in parallel to the substrate surface.

Accordingly, the refractive index of the liquid crystal, which is observed macroscopically, is small, and the contrast ratio is good and advantageous for a wide viewing angle.

On the other hand, the liquid crystal display device of the vertical alignment type has a pair of transparent substrates having transparent electrodes formed on the inner surface thereof, a liquid crystal material injected between the two substrates and aligned vertically to the substrate surface, And polarizing light by attaching the compensating film to the inside of the polarizing plate to compensate the viewing angle, thereby realizing a wide viewing angle.

Recently, an opening pattern is formed in a transparent electrode or a projection is formed, and a mode in which multiple division is performed without rubbing is proposed.

From this point of view, a general liquid crystal display device realizing a wide viewing angle will be described with reference to FIG.

1 is a cross-sectional view schematically illustrating a conventional liquid crystal display device.

1, a conventional liquid crystal display device includes a thin film transistor array substrate 11 and a color filter substrate 41 which are bonded together so as to face each other with a uniform gap therebetween. The thin film transistor array substrate 11 and the color filter substrate 41 The liquid crystal layer 51 is interposed.

Here, the thin film transistor array substrate 11 has pixels arranged in a matrix, and a thin film transistor 20, a pixel electrode 27, and a capacitor (not shown) are formed in the unit pixel. The thin film transistor 20 includes a gate electrode 13 formed on the array substrate 11, a gate insulating film 15 formed on the array substrate 11 including the gate electrode 13, And source / drain electrodes 21 and 23 formed on the semiconductor layer 17 and spaced apart from each other by a predetermined distance. The pixel electrode 27 is electrically connected to the drain electrode (not shown) through a drain contact hole (not shown) formed in a protective film 25 formed on the entire surface of the array substrate 11 including the source / drain electrodes 21 and 23, 23 are electrically connected to each other.

The color filter substrate 41 includes a common electrode 47 for applying an electric field to the liquid crystal layer 51 together with the pixel electrode 27 and an RGB color filter 45 and a black matrix 43 are formed.

An alignment film (not shown) is formed on the opposing surfaces of the thin film transistor array substrate 11 and the color filter substrate 41, and the liquid crystal is arranged in a predetermined direction on the surface of the alignment film (not shown) by rubbing.

At this time, when an electric field is applied between the pixel electrode 27 formed for each unit pixel of the thin film transistor array substrate 11 and the common electrode 47 formed on the front surface of the color filter substrate 41, , A character or an image is displayed by passing or blocking light for each unit pixel.

On the other hand, the first and second polarizing plates 61 and 63 are provided on the color filter substrate 41 and the thin film transistor array substrate 11, respectively. At this time, the polarizers 61 and 63 have a function of making natural light incident thereon vibrate in various directions and become light (i.e., polarized light) vibrating only in one direction.

In the light path of the conventional liquid crystal display device constructed as described above, the light of the backlight source is scattered in all directions to emit light, and the emitted light passes through several diffusion sheets (not shown) to obtain uniform luminance characteristics .

Accordingly, the lights incident on the liquid crystal display panel are incident in the omnidirectional direction, so that an image can be observed at a wide viewing angle.

A general liquid crystal display device has been studied with a wide viewing angle mode directivity as described above, but a narrow viewing angle mode may be required in a specific case.

However, according to the conventional liquid crystal display device, the light incident on the panel is incident in the omnidirectional direction, so that an image can be observed at a wide viewing angle. However, the narrow viewing angle and the wide viewing angle can not be actively controlled There are disadvantages.

Although it is not shown in the drawings, it is possible to narrow the viewing angle by using a film type filter or an optical fiber. However, it is difficult to switch the wide viewing angle and the narrow viewing angle, There is a problem of excessive reduction.

Accordingly, it is an object of the present invention to provide a liquid crystal display device capable of switching between a wide viewing angle mode and a narrow viewing angle mode as needed.

According to an aspect of the present invention, there is provided a liquid crystal display device capable of switching between a wide viewing angle mode and a narrow viewing angle mode, including: an array substrate; A first thin film transistor and a second thin film transistor formed on the array substrate; A first pixel electrode connected to the first thin film transistor and a second pixel electrode connected to the second thin film transistor; A black matrix, a color filter layer, and a common electrode formed on the color filter substrate; And a liquid crystal layer interposed between the array substrate and the color filter substrate.

According to another aspect of the present invention, there is provided a method of fabricating a liquid crystal display device capable of switching between a wide viewing angle mode and a narrow viewing angle mode, including: providing an array substrate and a color filter substrate; Forming a first thin film transistor and a second thin film transistor on the array substrate; Connecting a first pixel electrode to the first thin film transistor and forming a second pixel electrode in the second thin film transistor; Forming a black matrix, a color filter layer, and a common electrode on the color filter substrate; And interposing a liquid crystal layer between the array substrate and the color filter substrate.

Hereinafter, a liquid crystal display market value capable of switching between the wide viewing angle mode and the narrow viewing angle mode according to the present invention will be described in detail with reference to FIG. 2 to FIG.

2 is a cross-sectional view of a liquid crystal display device capable of switching modes between a wide viewing angle and a narrow viewing angle according to the present invention.

FIG. 3 is a diagram illustrating a liquid crystal display device capable of switching modes between a wide viewing angle and a narrow viewing angle according to an embodiment of the present invention, in which the liquid crystal alignment in one pixel is formed in a two- is a schematic view showing a liquid crystal alignment direction of each subpixel in one pixel of b).

FIG. 4 is a cross-sectional view of a liquid crystal display device capable of switching modes between a wide viewing angle and a narrow viewing angle according to the present invention, when the wide viewing angle is realized.

FIG. 5 is a cross-sectional view of a liquid crystal display device when a narrow angle of view is realized in a liquid crystal display device capable of switching between a wide viewing angle and a narrow viewing angle according to the present invention.

2, a liquid crystal display device capable of switching between a wide viewing angle mode and a narrow viewing angle mode according to the present invention includes a backlight (not shown) and a liquid crystal display panel 100 disposed on the backlight (not shown) .

The thin film transistor array substrate 111 and the color filter substrate 141 are bonded to each other with a uniform gap therebetween so that the thin film transistor array substrate 111 and the color filter substrate 141 The liquid crystal layer 151 is interposed.

2 and 4, the thin film transistor array substrate 111 includes first and second thin film transistors 110 and 120, first and second thin film transistors 110 and 120, First pixel electrodes 125 and 131 and a capacitor (not shown) connected to each of the second thin film transistors 110 and 120 are formed. A first pixel electrode 125 and a second pixel electrode 131 are formed in one pixel with a second insulating layer 127 therebetween and the first pixel electrode 125 and the second pixel electrode 131 ) Are formed in different areas. Further, the first thin film transistor 110 and the second thin film transistor 120 are used for controlling the wide viewing angle and the narrow viewing angle.

The first and second thin film transistors 110 and 120 include a gate electrode 113 formed on the array substrate 111 and a gate electrode 113 formed on the array substrate 111 including the gate electrode 113. [ And source / drain electrodes 119 and 121 formed on the insulating layer 115 and the semiconductor layer 117 and the semiconductor layer 117 and spaced apart from each other by a predetermined distance.

Each of the pixel electrodes 125 and 131 may include a drain and a drain formed in the first and second protective films 123 and 127 formed on the entire surface of the array substrate 111 including the source / And is electrically connected to the drain electrode 123 through a contact hole (not shown).

The color filter substrate 141 includes a common electrode 147 for applying an electric field to the liquid crystal layer 151 together with the pixel electrode 127 and an RGB color filter 145 and a black matrix 143 are formed.

An alignment film (not shown) is formed on the opposing surfaces of the thin film transistor array substrate 111 and the color filter substrate 141, and liquid crystal is arranged in a predetermined direction on the surface of the alignment film (not shown) by rubbing. At this time, the liquid crystal is applied between the first and second pixel electrodes 125 and 131 formed on the unit pixel of the thin film transistor array substrate 111 and the common electrode 147 formed on the front surface of the color filter substrate 141 , It is rotated by the dielectric anisotropy so that the light is passed or blocked for each unit pixel to display a character or an image.

First and second polarizing plates 161 and 163 are provided on the back surface of the color filter substrate 141 and the thin film transistor array substrate 111, respectively. At this time, the polarizers 161 and 163 have a function of vibrating the natural light incident thereon while vibrating in various directions to be a light (i.e., polarized light) vibrating only in one direction.

In a liquid crystal display device capable of switching between the wide viewing angle mode and the narrow viewing angle mode as described above, the driving principle of the liquid crystal display device will be described.

The two first and second thin film transistors 110 and 120 receive the same pixel voltage and transmit the same voltage to the liquid crystal layer 151. A small voltage difference is caused by the insulating film according to the region to have two tilt angles Liquid crystal layers 151 are formed. This can improve the gray inversion and the white inversion as shown in FIG. 3, thereby widening the left and right viewing angles.

In addition, the tilt angle can be adjusted by a method in which a voltage is artificially set in two areas and a signal is applied.

Meanwhile, as shown in FIG. 3, the liquid crystal alignment in one pixel is formed in a two-domain manner. For this purpose, a UV alignment or an ion beam alignment is used.

In this way, when the liquid crystal is aligned and applied as shown in Fig. 3, the gray-scale version of the left side (a in Fig. 3) and the right side (b in Fig. 3) can be improved to improve the viewing angle.

5 is a cross-sectional view of a liquid crystal display device for implementing a narrow viewing angle in a liquid crystal display device capable of switching modes between a wide viewing angle and a narrow viewing angle according to the present invention. Unlike the wide viewing angle mode, in the narrow viewing angle mode, The voltage that gives the actual pixel information is transmitted only to the second thin film transistor 120, and the first thin film transistor 110 serves as a compensation signal to which the same pixel potential can be applied across the pixel.

As a result, it operates in the same manner as the normal TN mode driving, and as shown in Fig. 3, a gray version (excess dark) occurs in the left and right viewing angles, narrowing the viewing angle.

As described above, according to the liquid crystal display device capable of switching between the wide viewing angle mode and the narrow viewing angle mode according to the present invention, the optically compensated multi-gray scale structure capable of improving the gray- a multi gray scale structure is applied, and a direction in which gray inversion occurs in one pixel is designed so as to be formed into left and right two domains.

Further, two thin film transistors are applied to enable a wide viewing angle and narrow viewing angle switching driving.

Therefore, the viewing angle control layer (film or liquid crystal layer) is structurally possible in its own cell without introducing it into the outside of the panel, which is advantageous in terms of cost and process.

Therefore, according to the present invention, it is possible to effectively control the wide viewing angle and the narrow viewing angle as necessary.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims. And changes may be made without departing from the spirit and scope of the invention.

Claims (11)

An array substrate and a color filter substrate; A first thin film transistor and a second thin film transistor formed on each of the unit pixels, wherein a plurality of unit pixels are arranged in a matrix form on the array substrate; A first pixel electrode connected to the first thin film transistor via an insulating film and a second pixel electrode connected to the second thin film transistor; A black matrix, a color filter layer, and a common electrode formed on the color filter substrate; And And a liquid crystal layer interposed between the array substrate and the color filter substrate. The liquid crystal display device according to claim 1, The liquid crystal display device according to claim 1, wherein the area of the first pixel electrode is different from the area of the second pixel electrode. The liquid crystal display device according to claim 1, wherein a polarizing plate is provided on each of the array substrate and the back surface of the color filter substrate. delete Providing an array substrate and a color filter substrate on which a plurality of unit pixels are arranged in a matrix form; Forming a first thin film transistor and a second thin film transistor on each of the unit pixels arranged on the array substrate; Forming a first protective layer on the entire surface of the array substrate including the first thin film transistor and the second thin film transistor to expose the first thin film transistor; Forming a first pixel electrode connected to the exposed first thin film transistor on the first protective film; Forming a second passivation layer on the first passivation layer including the first pixel electrode; Exposing the second thin film transistor by etching the second protective film and the first protective film; Forming a second pixel electrode connected to the exposed second thin film transistor on the second protective film; Forming a black matrix, a color filter layer, and a common electrode on the color filter substrate; And And interposing a liquid crystal layer between the array substrate and the color filter substrate. A method of manufacturing a liquid crystal display device, comprising: 6. The method of claim 5, wherein the area of the first pixel electrode and the area of the second pixel electrode are different from each other. 6. The method of claim 5, wherein a polarizing plate is provided on each of the array substrate and the back surface of the color filter substrate. delete 6. The method of claim 5, further comprising the step of aligning the liquid crystal on the array substrate and the color filter substrate. 10. The method of claim 9, wherein the liquid crystal alignment in one pixel is formed by two-domain. 6. The liquid crystal display of claim 5, wherein in the case of a narrow viewing angle, a voltage for giving actual pixel information is transmitted only to the second thin film transistor, and the first thin film transistor is used as a compensation signal to which the same pixel potential can be applied across the pixel Wherein the liquid crystal display device is capable of switching between a wide viewing angle mode and a narrow viewing angle mode.

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