KR20120115002A - Array substrate for in-plane switching mode liquid crystal display device - Google Patents

Abstract

PURPOSE: An array substrate for an in-plane switching mode liquid crystal display device is provided to minimize a change of a color difference and increase white brightness. CONSTITUTION: Red, green, and blue sub pixel areas(P1~P3) form one pixel area. A common electrode and a pixel electrode are defined as one block. An even number of blocks are formed on the red, green, and blue sub pixel areas. The common electrode and the pixel electrode are separated from the red, green, and blue sub pixel areas. (3n+1) or (3n+2) blocks are formed on one pixel area. The sub pixel areas have asymmetric structures. n is a plus integer.

Description

Array substrate for in-plane switching mode liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to an array substrate for an in-plane switching mode liquid crystal display device having improved white luminance characteristics.

Generally, the driving principle of a liquid crystal display device utilizes the optical anisotropy and polarization properties of a liquid crystal. Since the liquid crystal has a long structure, it has a directionality in the arrangement of molecules, and the direction of the molecular arrangement can be controlled by artificially applying an electric field to the liquid crystal.

Therefore, when the molecular alignment direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular alignment direction of the liquid crystal by optical anisotropy, so that image information can be expressed.

Currently, an active matrix liquid crystal display device (AM-LCD: below an active matrix LCD, abbreviated as a liquid crystal display device) in which a thin film transistor and a pixel electrode connected to the thin film transistor are arranged in a matrix manner has the highest resolution and moving picture performance. It is attracting attention.

The liquid crystal display includes a color filter substrate on which a common electrode is formed, an array substrate on which pixel electrodes are formed, and a liquid crystal layer interposed between the two substrates. In such a liquid crystal display, an electric field applied up and down between the common electrode and the pixel electrode is disposed. By the method of driving a liquid crystal, it is excellent in characteristics, such as transmittance | permeability and aperture ratio.

However, the liquid crystal drive due to the electric field applied up and down has a disadvantage that the viewing angle characteristics are not excellent.

Accordingly, a transverse field type liquid crystal display device having excellent viewing angle characteristics has been proposed to overcome these disadvantages.

Hereinafter, a general transverse electric field type liquid crystal display device will be described.

1 is a cross-sectional view of a general transverse electric field type liquid crystal display device.

As shown in the figure, in the transverse electric field type liquid crystal display device, the upper substrate 9, which is a color filter substrate, and the lower substrate 10, which is an array substrate, are spaced apart from each other to face each other, and the liquid crystal is disposed between the upper and lower substrates 9, 10. The layer 11 is interposed.

The common electrode 17 and the pixel electrode 30 are formed on the lower substrate 10 on the same plane. In this case, the liquid crystal layer 11 is formed by the common electrode 17 and the pixel electrode 30. It is operated by the horizontal electric field (L).

2A and 2B are cross-sectional views illustrating operations of on and off states of a general transverse electric field type liquid crystal display device, respectively.

First, referring to FIG. 2A, which illustrates an arrangement of liquid crystals in an on state where a voltage is applied, a phase change of a liquid crystal 11a at a position corresponding to the common electrode 17 and the pixel electrode 30 is performed. Although the liquid crystal 11b positioned in the section between the common electrode 17 and the pixel electrode 30 is formed by the horizontal electric field L formed by applying a voltage between the common electrode 17 and the pixel electrode 30, It is arranged in the same direction as the horizontal electric field (L). That is, in the transverse electric field type liquid crystal display device, since the liquid crystal moves by the horizontal electric field, the viewing angle is widened.

Therefore, when viewed from the front, the transverse electric field type liquid crystal display device can be seen in the up / down / left / right directions even without reversal in the 80 ° to 89 ° direction.

Next, referring to FIG. 2B, since no horizontal electric field is formed between the common electrode 17 and the pixel electrode 30 in the off state in which no voltage is applied to the liquid crystal display, the liquid crystal layer 11 is arranged. The state does not change.

FIG. 3 is a view schematically illustrating a common electrode and a pixel electrode provided in one pixel region including red, green, and blue subpixel regions as one block in a conventional array substrate for a transverse electric field type liquid crystal display device. to be.

As shown in the drawing, in the case of a conventional array substrate for a transverse electric field type liquid crystal display device, one common electrode CE and one pixel are adjacent to each other in each of the red, green, and blue subpixel regions P1, P2, and P3. The electrode PE forms one block, and each of the red, green, and blue sub-pixel areas P1, P2, and P3 is formed of the same even number of blocks BL, and red, green, and the like according to design rules. One pixel region P including the blue subpixel regions P1, P2, and P3 is composed of blocks BL of multiples of three.

On the other hand, when the same power consumption is achieved in the liquid crystal display device, it is advantageous to improve the contrast ratio and provide an image of excellent display quality when the brightness is brighter.

A person has a visual perception characteristic, and green is actually the largest involvement of a person in recognizing white, and therefore, a larger area ratio of green makes a user more aware of white.

However, in the conventional transverse electric field type liquid crystal display device, the white luminance characteristics are reduced because the red, green, and blue subpixel regions P1, P2, and P3 are all made of the same number of blocks.

The present invention has been made to solve the above-described problems, and when the same power consumption is reflected to the visibility characteristics of the person, it is possible to improve the white luminance without distortion on the color coordinates, i.e., to minimize white color variations. It is an object of the present invention to provide an array substrate for an electric field type liquid crystal display device.

In the array substrate for a transverse electric field type liquid crystal display device according to the present invention for achieving the above object, a plurality of subpixel regions are defined by crossing the gate wiring and the data wiring, and each subpixel region is alternately spaced apart from each other. In an array substrate for a transverse electric field type liquid crystal display device provided with a plurality of pixel electrodes and a common electrode, the plurality of subpixel regions comprise red, green, and blue subpixel regions representing red, green, and blue. Each of the red, green, and blue subpixel regions, which are spaced apart from each other in the red, green, and blue subpixel regions and defines the neighboring common electrode and the pixel electrode as one block, has an even number of blocks in each of the red, green, and blue subpixel regions. An asymmetric structure is formed by forming 3n + 1 (n is an integer greater than or equal to 0) or 3n + 2 (n is an integer greater than or equal to 0) blocks in the region. All.

In this case, in the red, green, and blue subpixel areas, the number of blocks provided in the green subpixel area is larger than the number of blocks included in any one of the red and blue subpixel areas. to be.

In addition, the red, green, blue green sub-pixel region is characterized in that the block is configured to differ by at most two.

The transverse field type liquid crystal display array substrate may further include: the gate wiring formed extending in one direction; A common wiring formed to be spaced apart from the gate wiring in parallel with the gate wiring; A gate insulating film formed on an entire surface of the gate wiring and the common wiring; A data line formed over the gate insulating layer to define the plurality of sub-pixel regions crossing the gate line; A thin film transistor connected to the gate line and the data line in each subpixel area; A protective layer formed on the data line and the thin film transistor, the protective layer having a drain contact hole exposing the drain electrode of the thin film transistor and a common contact hole exposing the common wiring; A plurality of pixel electrodes formed in each of the sub-pixel regions, the plurality of pixel electrodes being in contact with the drain electrode through the drain contact hole and spaced apart from each other by a predetermined interval; A plurality of common electrodes are formed in each of the sub-pixel regions to contact the common wiring through the common contact hole and to alternate with the pixel electrode.

In the transverse field type liquid crystal display according to the present invention, the red, green, and blue sub-pixel regions have an asymmetric structure, thereby improving white luminance characteristics, and furthermore, by changing the design rule in which the pixel region consists of multiples of three blocks. By finely controlling the number of blocks in the red, green, and blue sub-pixel areas composed of blocks, it is possible to minimize the color difference due to the skew of the coordinates on the color coordinates and to improve the average luminance and transmittance.

1 is a cross-sectional view schematically showing a part of a general transverse electric field type liquid crystal display device.
2A and 2B are cross-sectional views showing operations in off and on states of a general transverse electric field type liquid crystal display device, respectively.
FIG. 3 is a view schematically illustrating a common electrode and a pixel electrode provided in one pixel region including red, green, and blue subpixel regions as one block in a conventional array substrate for a transverse electric field type liquid crystal display device. .
4 is a schematic plan view of one blue subpixel region in an array substrate for a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention.
FIG. 5 is a view briefly showing only blocks provided in red, green, and blue subpixel regions in an array substrate for a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention; FIG.
6A to 6B schematically illustrate only red, green, and blue subpixel regions and blocks provided therein of an array substrate for a transverse electric field type liquid crystal display device according to still another exemplary embodiment of the present invention.
7A and 7B schematically illustrate only red, green, and blue subpixel regions and blocks provided therein of an array substrate for an asymmetric structure transverse field type liquid crystal display device according to a comparative example.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

4 is a schematic plan view of one blue subpixel area in an array substrate for a transverse electric field liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 5 is a transverse electric field liquid crystal display according to an embodiment of the present invention. Only the blocks provided in the red, green, and blue sub-pixel regions of the array substrate for the drawing are briefly shown.

First, as shown in FIG. 4, the array substrate 101 for a transverse electric field type liquid crystal display device according to an exemplary embodiment of the present invention has a plurality of gate lines 103 arranged in a horizontal direction in parallel with a predetermined interval therebetween. ), A plurality of common wirings 109 adjacent to each of the plurality of gate wirings 103 in parallel with the gate wiring 103, and a plurality of subpixel regions P1 intersecting with the gate wiring 103. 5, P2 of FIG. 5, and P3 of FIG. 5 are formed.

Near the intersection of the gate line 103 and the data line 130, the gate electrode 106, the gate insulating layer (not shown), and the semiconductor layer are formed for each subpixel area P1, P2 of FIG. 5, and P3 of FIG. 5. A thin film transistor Tr, which is a switching element composed of the 120 and the source and drain electrodes 133 and 136, is formed. In this case, the source electrode 133 is connected to the data line 130, and the gate electrode 106 is connected to the gate line 103.

On the other hand, each of the sub-pixel areas P1, P2 of FIG. 5, and P3 of FIG. 5 contacts the common wiring 109 through the common contact hole 147, and a plurality of common electrodes CE are spaced at regular intervals. Spaced apart from each other, the ends of the plurality of common electrodes CE are connected by an auxiliary common pattern 175.

In addition, an auxiliary pixel pattern 169 connected to the drain electrode 136 of the thin film transistor Tr is formed in each pixel region P1, P2 of FIG. 5, and P3 of FIG. 5. The plurality of pixel electrodes PE are alternately formed to overlap the common wiring 109 and branch from the auxiliary pixel pattern 169 to be spaced apart from the common electrode CE.

In this case, the common wiring 109 and the auxiliary pixel pattern 169 formed to overlap each other form a storage capacitor StgC.

Each of the sub-pixel regions P1, P2 of FIG. 5, and P3 of FIG. 5 having such a configuration has a common electrode CE adjacent to the data line 160, and thus, a pair of common electrodes CE adjacent to each other. And the plurality of blocks BL defined by the pixel electrodes PE are always even in each of the subpixel areas P1, P2 of FIG. 5, and P3 of FIG. 5.

In the drawing, when one pixel electrode PE defining one block BL and the neighboring common electrode CE are subtracted or increased in order to reduce or increase the block BL, each subpixel area P1 and FIG. In P2 of FIG. 5 and P3 of FIG. 5, it can be seen that the number of blocks BL is always generated in two units. Therefore, due to this phenomenon, each subpixel area P1, P2 of FIG. 5, and P3 of FIG. 5 are always made of even blocks BL.

In this case, the most characteristic of the transverse electric field type liquid crystal display device according to the embodiment of the present invention is the number of blocks BL in the red, green, and blue subpixel areas P1, P2, and P3. In one pixel area (P in FIG. 5) consisting of three sub-pixel areas P1, P2 in FIG. 5, and P3 in FIG. 5, which represent red, green, and blue, the number of total blocks BL is a multiple of three. Is not going to be. That is, the number of total blocks BL included in one pixel area (P in FIG. 5) is 3n + 1 (n is an integer greater than or equal to 0) or 3n + 2 (n is an integer greater than or equal to 0). .

Preferably, the difference in the number of blocks BL between the red, green, and blue sub-pixel areas P1, P2, and P3 is two.

For example, referring to FIG. 5, it can be seen that the red and blue subpixel regions P1 and P3 are composed of six blocks BL, while the green subpixel region P2 is composed of eight blocks BL. have. In this case, one pixel area P is composed of a total of 20 blocks BL, so that 3n + 2 (n is an integer greater than or equal to 0) is not a multiple of 3.

In the embodiment of the present invention, the red, green, and blue sub-pixel areas P1, P2, and P3 are formed to have an asymmetrical structure to satisfy the conditions as described above to improve white luminance characteristics by reflecting human visibility. For sake.

Furthermore, in the exemplary embodiment of the present invention, the red, green, and blue subpixel regions P1, P2, and P3 have an asymmetric structure, but the block BL does not have a multiple of 3 for one pixel region P. FIG. In other words, the configuration of 3n + 1 (n is an integer greater than or equal to 0) or 3n + 2 (n is an integer greater than or equal to 0) means that the block BL improves the white luminance characteristic and changes the color difference in one pixel region P. This is to minimize the

In order to express white, green contributes the most, but red and blue also contribute, so if the area ratio of the green subpixel area (P2) is increased, the balance of red, green, and blue is broken, which is out of the allowable range on the color coordinate. In this case, color coordinate correction is required.

Color coordinate correction is to adjust the brightness of the backlight, etc. In this case, the overall brightness characteristics may be reduced, which is a negative factor in achieving the purpose of improving the brightness characteristics.

Therefore, in the embodiment of the present invention, when adjusting the number of blocks BL in each of the subpixel areas P1, P2, and P3, a sudden increase in the area of the green subpixel area p2 is suppressed to balance red, green, and blue colors. The white luminance characteristic can be improved while maintaining a level similar to the color difference in white representation of a conventional transverse field type liquid crystal display array substrate having the same number of blocks BL for each subpixel region P1, P2, and P3. The block BL structure in each pixel region of the transverse electric field type liquid crystal display array substrate 101 is proposed.

6A to 6B schematically illustrate only red, green, and blue subpixel regions and blocks provided therein of an array substrate for a transverse electric field type liquid crystal display device according to still another exemplary embodiment of the present invention.

In the case of FIG. 6A, the green and blue subpixel areas P2 and P3 are made up of six blocks BL, while the red subpixel area P1 is made up of four blocks BL. P) consists of a total of 16 blocks (BL), indicating that this is also not a multiple of three.

In addition, in FIG. 6B, it can be seen that the red and green subpixel regions P1 and P2 are composed of six blocks BL, while the blue subpixel region P3 is composed of four blocks BL. . In this case, it can be seen that one pixel area P is not a multiple of 3 since the pixel block P is composed of a total of 20 blocks BL.

7A and 7B schematically illustrate only red, green, and blue subpixel regions and blocks provided therein of an asymmetric structure transverse field type liquid crystal display array substrate according to a comparative example.

In the array substrate 201 for an asymmetric structure transverse field type liquid crystal display device according to the comparative example, the red, green, and blue subpixel regions P1, P2, and P3 are all made up of an even number of blocks BL. It can be seen that one pixel area P is formed to have the number BL of multiples of three.

First, referring to FIG. 7A, it can be seen that the red, green, and blue subpixel areas P1, P2, and P3 have 6, 8, and 4 numbers, respectively. Referring to FIG. 7B, the red, green, and blue subpixels are illustrated. It can be seen that the regions P1, P2, and P3 are each composed of 4, 10 and 4 numbers.

The asymmetric structure transverse field type liquid crystal display array substrate 201 according to the comparative example has such a configuration because the pixel region P is configured to satisfy the design rule of blocks BL of multiples of three. In the comparative example shown in 7a, two blocks BL provided in the blue subpixel area P3 in the red, green, and blue subpixel areas P1, P2, and P3 are basically divided into six blocks BL. This is achieved by moving to the green subpixel area P2.

In addition, in the comparative example illustrated in FIG. 7B, all of the blocks BL included in the red and blue subpixel regions P1 and P3 are moved to the green subpixel region P2.

In the comparative example having such a configuration, at least four block BLs occur in any two subpixel areas in the red, green, and blue subpixel areas P1, P2, and P3, so that each subpixel area is even. When the area of the green subpixel area P2 is increased due to the characteristics of the two blocks BL, the area ratio of the red or blue subpixel areas P1 and P3 decreases relatively, so that the red, green, and blue balances collapse. This is beyond the required color difference of white.

Table 1 shows the transmittance and color difference characteristics of the transverse field type liquid crystal display device having the array substrate having a conventional symmetrical structure and the comparative example having the array substrate having an asymmetric structure, Table 2 The transmissive field and the color difference characteristics of a transverse field type liquid crystal display device having an array substrate having a conventional symmetric structure and an array substrate having an asymmetric structure are shown.

TABLE 1

<Table 2>

First, referring to Table 1, in the case of an array substrate for an asymmetric structure transflective liquid crystal display device according to a comparative example consisting of blocks of multiples of three of the pixel region, compared with a conventional transflective liquid crystal display device having a symmetrical structure in terms of transmittance Although improved, it can be seen that the color coordinates are caused to deviate from the range of white coordinates typically required in the liquid crystal display.

That is, in the comparative example, in the color coordinate system, the x coordinate and the y coordinate are different from each other by 0.018 or more in comparison with the white reference coordinate (0.279, 0.292) in the color coordinate system, and in particular, at least one of the x coordinate and the y coordinate. It can be seen that the difference between the relatively large value of 0.030 to 0.060.

However, in the exemplary embodiment of the present invention, it can be seen that an improvement of about 3% to 5% is achieved in terms of transmittance compared to the conventional transverse electric field type liquid crystal display having a symmetrical structure. Furthermore, the maximum value of the color coordinate change ratio of white is 0.016 or less. It is understood that a color difference with a large change rate of 0.16 or more does not occur.

On the other hand, an array substrate for an asymmetric structure transverse field type liquid crystal display device having the above-described configuration can reduce the difference in area ratio between red, green, and blue subpixel areas compared to the comparative example, thereby reducing the area difference between red, green, and blue subpixel areas. As a result, the white luminance characteristic can be improved and the change in color difference is minimized, thereby improving the luminance characteristic without color difference correction.

101: transverse field array substrate
BL: block
CE: Common Electrode
PE: pixel electrode
P: pixel area
P1, P2, P3: Red, Green, Blue Subpixel Area

Claims (4)

In an array substrate for a transverse field type liquid crystal display device having a plurality of subpixel regions defined by crossing gate lines and data lines, and having a plurality of pixel electrodes and a common electrode alternately spaced apart from each other.
In the plurality of subpixel areas, red, green, and blue subpixel areas representing red, green, and blue colors constitute one pixel area, and common and pixel electrodes adjacent to each other are spaced apart from each other in the red, green, and blue subpixel areas. When a is defined as one block, the red, green, and blue subpixel areas are provided with even blocks, respectively, and one pixel area has 3n + 1 (n is an integer greater than 0) or 3n + 2, not a multiple of 3. An array substrate for a transverse electric field liquid crystal display device characterized by forming an asymmetric structure by forming (n is an integer of 0 or more) blocks.
The method of claim 1,
Wherein, in the red, green, and blue subpixel areas, the number of blocks provided in the green subpixel area is larger than the number of blocks included in any one of the red and blue subpixel areas. Array substrate for electric field type liquid crystal display device.
The method of claim 2,
And at least two blocks in the red, green, and blue green subpixel areas.
4. The method according to any one of claims 1 to 3,
On the array substrate for a transverse electric field type liquid crystal display device,
The gate line formed extending in one direction;
A common wiring formed to be spaced apart from the gate wiring in parallel with the gate wiring;
A gate insulating film formed on an entire surface of the gate wiring and the common wiring;
A data line formed over the gate insulating layer to define the plurality of sub-pixel regions crossing the gate line;
A thin film transistor connected to the gate line and the data line in each subpixel area;
A protective layer formed on the data line and the thin film transistor, the protective layer having a drain contact hole exposing the drain electrode of the thin film transistor and a common contact hole exposing the common wiring;
A plurality of pixel electrodes formed in each of the sub-pixel regions, the plurality of pixel electrodes being in contact with the drain electrode through the drain contact hole and spaced apart from each other by a predetermined interval;
And a plurality of common electrodes in contact with the common wiring through the common contact hole, the plurality of common electrodes being formed in the sub-pixel regions to contact the common wiring through the common contact hole.

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