KR100943268B1 - Liquid crystal display - Google Patents

Abstract

A liquid crystal display for removing butterfly spots generated in twisted nematic mode is disclosed. The lamp emits light, and the liquid crystal display panel includes a thin film transistor substrate and an opposing substrate facing the thin film transistor substrate. Further, the liquid crystal display panel is formed between the thin film transistor substrate and the counter substrate, and Δnd compensated in response to the temperature increasing as the lamp emits light, where Δn is the refractive index anisotropy of the liquid crystal and d is the cell gap of the liquid crystal. The liquid crystal layer which has is provided. Accordingly, the refractive index anisotropy of the liquid crystal decreases in response to the increasing temperature as the backlight assembly is driven, or the left and right or upper and lower butterfly stains can be removed by increasing the cell gap of the liquid crystal layer.

Twist Nematic, Butterfly Smudge, Rubbing Direction, Cell Gap, Seal Line

Description

Liquid crystal display {LIQUID CRYSTAL DISPLAY}

1 is a view for explaining a general liquid crystal display device.

2A and 2B are diagrams for explaining butterfly unevenness in the liquid crystal display device employing the TN mode.

3A and 3B illustrate a liquid crystal display according to a first exemplary embodiment of the present invention.

4A and 4B illustrate a liquid crystal display according to a second exemplary embodiment of the present invention.

5 is a diagram for describing a liquid crystal display according to a third exemplary embodiment of the present invention.

6 is a diagram for describing a liquid crystal display according to a fourth exemplary embodiment of the present invention.

7 is a diagram for describing a liquid crystal display according to a fifth exemplary embodiment of the present invention.

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

110, 210, 310: backlight 112, 212, 418: light guide plate

120, 220, 320: liquid crystal panel 122, 222, 322: array substrate                 

124, 224, 324: color filter substrate 126, 127, 326: seal line member

The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display for removing butterfly spots generated in the twisted nematic mode.

In general, the refractive index anisotropy (Δn) of the liquid crystal has a characteristic of decreasing with increasing temperature.

FIG. 1 is a diagram for explaining a general liquid crystal display, and particularly for explaining an edge type liquid crystal display having a flat light guide plate.

As shown in FIG. 1, a liquid crystal panel included in a general edge type liquid crystal display device includes an array substrate 12 having a plurality of thin film transistors (TFTs), a color filter substrate 14 having a plurality of color filters, It is made of a seal line member 16 for blocking the separation of the liquid crystal formed between the array substrate and the color filter substrate.

When viewed from the front of the liquid crystal panel, the temperature of the upper and lower edge regions where the lamps 22 and 26 are disposed and the temperature of the remaining regions where the lamps 22 and 26 are not placed are different, so that Δnd ( Here, Δn is the refractive index anisotropy of the liquid crystal, and d is the cell gap of the liquid crystal. Here, the edge type liquid crystal display device includes lamps 22 and 26 at one side or both sides of the light guide plate 20, and displays an image by guiding the light provided from the lamps 22 and 26. to be.                         

On the other hand, in a liquid crystal display device employing a TN (Twist Nematic) mode, a retardation film is used to suppress light leakage generated in a black display. In this case, in order to compensate for the refractive anisotropy of the liquid crystal, the critical retardation rate (Rth) of the retardation film may be taken as one. Here, the critical delay rate Rth is defined by Equation 1 below.

Here, n _x is the x-axis delay, n _y is the y-axis delay, n _z is the z-axis delay, and d is the thickness of the retardation film.

Meanwhile, in the liquid crystal display device employing the TN mode, the transmission axis direction of the upper polarizing plate and the transmission axis direction of the lower polarizing plate cross 45 degrees and 135 degrees, respectively, so that the upper, lower, left, and right directions are 45 degrees relative to the polarizing plate, so that the liquid crystal cell and the upper and It is the area most sensitively affected by the mismatch of the lower polarizer delay phenomenon. That is, when viewed from the plane of the liquid crystal panel, the upper and lower cell delays and the left and right cell delays are different, resulting in various butterfly stains.

That is, as shown in Figure 2a, if the retardation of the retardation film is matched to the delay of the left and right region of the liquid crystal panel, the upper and lower cell delay is small, there is a problem that light leakage phenomenon (or upper and lower butterfly staining) occurs on the upper and lower sides .

In addition, as shown in Figure 2b, if the retardation of the retardation film is matched to the upper and lower sides, the left and right cell delay is large, there is a problem that light leakage phenomenon (or left and right butterfly unevenness) occurs on the left and right.

In order to solve the conventional problems, an object of the present invention is to provide a liquid crystal display for removing left and right butterfly spots and top and bottom butterfly spots in a liquid crystal display device employing a twisted nematic mode. To provide.

According to an aspect of the present invention, there is provided a liquid crystal display device comprising: a lamp for emitting light; And Δnd formed between the thin film transistor substrate, the opposing substrate facing the thin film transistor substrate, the thin film transistor substrate and the opposing substrate, and compensated in response to a temperature increasing as the lamp emits the light. A liquid crystal layer having a refractive index anisotropy of the liquid crystal, and d a cell gap of the liquid crystal; and a liquid crystal display panel displaying an image in response to the potential difference applied to the liquid crystal layer and the light. Is done.

Here, a seal line member is formed in the edge region of the thin film transistor substrate and the opposing substrate to block the separation of the liquid crystal layer. It is characterized in that it is formed thicker than the thickness of the seal line member corresponding to the arranged edge region or further comprising a separate layer.                     

The thin film transistor substrate further includes a first polarizing plate having a transmission axis in a first direction, and a second polarizing plate having a transmission axis in a second direction is further provided on an upper surface of the opposing substrate. A first alignment layer rubbed in a first direction is further provided, and the opposing substrate further includes a second alignment layer rubbed in a second direction, and the cabinet is close to the lamp among angles formed by the first direction and the second direction. Is large, and the outer shell desired for the lamp is small.

In addition, the plurality of lamps, the plurality of lamps are arranged evenly on the back of the thin film transistor substrate or in the edge region of the thin film transistor substrate to compensate for the Δnd of the liquid crystal layer It features.

According to the liquid crystal display device, the left and right butterfly stains and the upper and lower butterfly stains can be removed by adjusting the refractive index anisotropy of the liquid crystals decreasing in response to an increase in temperature as the backlight assembly is driven or increasing the cell gap of the liquid crystal layer. .

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

3A and 3B are views for explaining a liquid crystal display device according to a first embodiment of the present invention. In particular, FIG. 3A is a plan view of a liquid crystal display device having a cell gap adjusted in consideration of a lamp arrangement, and FIG. 3B is A A cross-sectional view along the cutting line of -A 'is shown.

Referring to FIG. 3A, the liquid crystal display 100 according to the first exemplary embodiment of the present invention includes a backlight unit 110 that emits light, and a liquid crystal panel that displays an image using the light and the liquid crystal embedded therein. The unit 120 includes.

The backlight unit 110 fixes the light guide plate 112, a plurality of lamps 114 and 115 to supply light to both sides of the light guide plate 112, and the lamps 114 and 115 are fixed to both sides of the light guide plate 112, respectively. The lamp covers 116 and 117 block the leakage of the light while guiding the path of the light emitted from the lamps 114 and 115 using the light guide plate 112, and guided light to the liquid crystal panel unit 120. To provide.

The liquid crystal panel 120 includes an array substrate (or a thin film transistor substrate) including a plurality of gate lines, data lines insulated from the gate lines, switching elements connected to the gate lines and data lines, and pixel electrodes connected to the switching elements. A leakage of a liquid crystal (not shown) formed between the color filter substrate 124 having a plurality of color filters facing the pixel electrode, and the array substrate 122 and the color filter substrate 124. Including a seal line member 126 to block the image, and displays an image in response to the light provided from the backlight unit (110).

For example, as shown in FIG. 3B, in consideration of the position of the backlight unit 110, the thickness of the first seal line member 126 extending in the horizontal direction, that is, the area close to the lamps 114 and 115. Is formed thicker than the thickness of the first sealing line member 126 extending in the longitudinal direction, that is, the area close to the lamps 114 and 115, so that the cell gap of the upper or lower portion of the liquid crystal panel 120 is different from the cell gap of the other region. Form thicker than That is, the cell gap is adjusted by adjusting the thicknesses of the first seal line member 126 in consideration of the positions of the lamps 114 and 115, thereby adjusting the refractive index anisotropy of the liquid crystal.                     

Of course, as shown in FIG. 3C, by further providing a separate layer 128 on the second seal line member 127 having the same thickness regardless of the positions of the lamps 114 and 115, the liquid crystal panel portion ( The cell gap of the upper side or the lower side of the 120 may be formed thicker than the cell gap of other regions.

Although the drawings show a flat light guide plate having the same thickness on both sides, it may be easily applied even if a wedge-shaped light guide plate having a different thickness on one side and a thickness on the other side is applied. That is, since the lamp is arranged on the surface having a thick thickness of the wedge-shaped light guide plate, the cell gap can be adjusted differently by forming a thicker seal line member or forming a separate layer in an area adjacent to the arranged lamps.

According to the first embodiment of the present invention described above, by varying the thickness of the seal line member or by forming another layer in consideration of the lamp arrangement, the left and right refractive anisotropy and the upper and lower refractive anisotropy of the liquid crystal can be similar. It can weaken the left and right butterfly stains and the top and bottom butterfly stains.

4A and 4B are views for explaining a liquid crystal display device according to a second embodiment of the present invention. In particular, FIG. 4A is a schematic perspective view for explaining a liquid crystal display device having a rubbing angle adjusted in consideration of a lamp arrangement. 4B is a schematic plan view of FIG. 4A.

Referring to FIG. 4A, the liquid crystal display 200 according to the second exemplary embodiment of the present invention may include a backlight unit 210 that emits light and a liquid crystal panel unit that displays an image using the light and the liquid crystal embedded therein. 220).                     

The backlight unit 210 fixes the light guide plate 212, a plurality of lamps 214 and 215 for supplying light to both sides of the light guide plate 212, and the lamps 214 and 215 are fixed to both sides of the light guide plate 212, respectively. The lamp covers 216 and 217 block the leakage of light while guiding the path of the light emitted from the lamps 214 and 215 using the light guide plate 212, and guide the guided light to the liquid crystal panel 220. To provide.

The liquid crystal panel 220 includes an array substrate (or a thin film transistor substrate) including a plurality of gate lines, a data line insulated from the gate line, a switching element connected to the gate line and the data line, and a pixel electrode connected to the switching element. 222, a first alignment layer 223 formed on the array substrate 222, a color filter substrate 224 having a plurality of color filters facing the pixel electrode, and a color filter substrate 224 formed below. A liquid crystal (not shown) formed between the second alignment layer 225, the first alignment layer 223, and the second alignment layer 225, the first polarizing plate 226 formed under the array substrate 222, and a color. Including a second polarizing plate 227 formed on the filter substrate 224, an image is displayed in response to the light provided from the backlight unit 110.

When viewed from the plane of the liquid crystal panel unit 220, the first rubbing direction 223R of the first alignment layer 223 and the second rubbing direction 225R of the second alignment layer 225 are orthogonal to each other at a predetermined angle. The liquid crystal layer (not shown) formed between the first alignment layer 223 and the second alignment layer 225 is tilted by a predetermined angle. Here, the liquid crystal layer formed between the first alignment layer 223 and the second alignment layer 225 is tilted smaller than 90 degrees. In this case, the first rubbing direction 223R and the first angle θ1 corresponding to the side where the lamp is disposed may be greater than the second angle θ2 corresponding to the side where the lamp is not disposed in consideration of the lamp arrangement. By adjusting the second rubbing direction 225R, the retardation of the upper and lower retardation films and the delay of the left and right retardation films differ.

As shown in FIG. 4B, when the liquid crystal panel unit 220 is viewed in plan, the transmission axis 226T and the color filter substrate 224 of the first polarizing plate 226 formed under the array substrate 222. The first rubbing direction 223R of the first alignment layer 223 and the second alignment layer 225 of the second alignment layer 225 are greater than an angle formed by the transmission axis 227T of the second polarizing plate 227 formed at an upper portion of the second polarizing plate 227. The rubbing direction 225R is implemented to have a large angle corresponding to the positions of the lamps 215 and 216. Of course, the angle between the first alignment layer 223 and the second alignment layer 225 is greater than the angle between the absorption axes of the first polarizing plate 226 and the second polarizing plate 227 corresponding to the positions of the lamps 215 and 216. You can also implement it.

As described above, the conventional rubbing treatment is performed such that the upper rubbing direction and the lower rubbing direction are 90 degrees. However, according to the second exemplary embodiment of the present invention, the inner angle of the upper rubbing direction and the lower rubbing direction is large in consideration of the lamp arrangement. By making the outer shell in contact with the lamp small, the upper and lower butterfly stains and the left and right butterfly stains of the liquid crystal panel can be weakened.

FIG. 5 is a diagram for describing a liquid crystal display according to a third exemplary embodiment of the present invention. In particular, FIG. 5 is a perspective view schematically illustrating a liquid crystal display having a direct lamp arrangement.

Referring to FIG. 5, the liquid crystal display 300 according to the third exemplary embodiment of the present invention includes a backlight unit 310 for emitting light, and a liquid crystal panel unit for displaying an image using the light and the liquid crystal embedded therein. 320).

The backlight unit 310 includes a storage container 312 defining an accommodation space by a bottom surface and four sidewalls, and a plurality of lamps 314 arranged at regular intervals on the bottom surface of the storage container 312. In addition, the light is provided to the liquid crystal panel unit 320.

The liquid crystal panel 320 includes an array substrate (or a thin film transistor substrate) including a plurality of gate lines, data lines insulated from the gate lines, switching elements connected to the gate lines and data lines, and pixel electrodes connected to the switching elements. 322, a color filter substrate 324 including a plurality of color filters facing the pixel electrode, and a liquid crystal (not shown) formed between the array substrate 322 and the color filter substrate 324. Including a seal line member 326 to block the display, the image is displayed in response to the light provided from the backlight unit (310). In this case, the seal line member 326 may be formed at the same height irrespective of the lamp arrangement, but may be formed to have a different height as mentioned in FIG. 3B in consideration of the lamp arrangement. As mentioned in FIG. 3C, a separate layer may be further formed on or under the seal line member having the same height.

According to the third embodiment of the present invention, by arranging the lamp arrangement in the direct type, the left and right refractive anisotropy and the upper and lower refractive anisotropy of the liquid crystal can be similar, so that the left and right butterfly unevenness and the upper and lower butterfly unevenness can be weakened.

FIG. 6 is a view for explaining a liquid crystal display device according to a fourth embodiment of the present invention. In particular, FIG. 6 is a perspective view schematically illustrating a liquid crystal display device having a rectangular lamp arrangement.

Referring to FIG. 6, the liquid crystal display 400 according to the fourth exemplary embodiment of the present invention includes a backlight unit 410 for emitting light, and a liquid crystal panel unit for displaying an image using the light and the liquid crystal embedded therein. 420).

The backlight unit 410 includes a storage container 412 defining an accommodation space by a bottom surface and four sidewalls, and a plurality of lamps 414 arranged along an area where the bottom surface and the sidewall of the storage container 412 meet. 415 and a light guide plate 418 disposed on the bottom surface of the storage container, guide the path of the light emitted from the lamps 414 and 415 by using the light guide plate 418, and guide the guided light to the liquid crystal panel. To the unit 420.

The liquid crystal panel unit 420 may include an array substrate (or a thin film transistor substrate) including a plurality of gate lines, data lines insulated from the gate lines, switching elements connected to the gate lines and data lines, and pixel electrodes connected to the switching elements. 422, a color filter substrate 424 including a plurality of color filters facing the pixel electrode, and a liquid crystal (not shown) formed between the array substrate 422 and the color filter substrate 424. Including a seal line member 426 to block the display, the image is displayed in response to the light provided from the backlight unit 410. In this case, the seal line member 426 may be formed at the same height irrespective of the lamp arrangement, but may be formed to have a different height as mentioned in FIG. 3B in consideration of the lamp arrangement. As mentioned in FIG. 3C, a separate layer may be further formed on or under the seal line member having the same height.

According to the fourth embodiment of the present invention, by arranging the lamp arrangement so that the quadrangle is defined, the left and right butterfly anisotropy and the upper and lower refractive anisotropy of the liquid crystal can be similar, so that the left and right butterfly unevenness or upper and lower butterfly unevenness can be weakened.

FIG. 7 is a diagram for describing a liquid crystal display according to a fifth exemplary embodiment of the present invention. In particular, FIG. 7 is a perspective view schematically illustrating an inverted-wedge type liquid crystal display.

Referring to FIG. 7, the liquid crystal display 500 according to the fifth exemplary embodiment of the present invention may include a backlight unit 510 for emitting light, and a liquid crystal panel unit for displaying an image using the light and the liquid crystal embedded therein. 520).

The backlight unit 510 may block the light leakage while fixing the light guide plate 512, a lamp 514 for supplying light to one side of the light guide plate 512, and fixing the lamp 514 to one side of the light guide plate 512. The lamp cover 516 guides the path of the light emitted from the lamp 514 using the light guide plate 512, and provides the guided light to the liquid crystal panel unit 520. Here, the light guide plate 512 has a wedge shape in which the thickness of one side and the thickness of the other side are different, and the lamp 514 is disposed above the liquid crystal display when the liquid crystal display is mounted to operate in a normal environment. In general, when the liquid crystal display device is employed in a notebook computer or the like, considering that the lamp is disposed below the liquid crystal display device so as to be close to the host side where the keyboard or the like is disposed, the above-described structure of FIG.

The liquid crystal panel unit 520 may include an array substrate (or a thin film transistor substrate) including a plurality of gate lines, a data line insulated from the gate line, a switching element connected to the gate line and the data line, and a pixel electrode connected to the switching element. 522, a color filter substrate 524 including a plurality of color filters facing the pixel electrode, and a liquid crystal (not shown) formed between the array substrate 522 and the color filter substrate 524. And a seal line member 526 that blocks leakage, and displays an image in response to the light provided from the backlight unit 510.

Here, the source PCB (not shown) for providing an image signal to the data line formed on the array substrate 522 is preferably disposed under the liquid crystal display panel. This is because the wedge-shaped light guide plate 512 efficiently uses the rear surface of the relatively thin region.

In addition, although the seal line member 526 may be formed at the same height regardless of the lamp arrangement, the seal line member 526 may be formed to have a different height as mentioned in FIG. 3B in consideration of the lamp arrangement. As described above with reference to FIG. 3C, a separate layer may be further formed on or under the seal line member having the same height.

According to this fifth embodiment of the present invention, the lamp is placed on the upper side of the liquid crystal panel in consideration of the fact that the heat generated in general is higher in the amount moving upward than the amount moving downward. Accordingly, the heat generated by the driving of the lamp can be discharged out of the liquid crystal panel as much as possible, so that the left and right refractive anisotropy and the upper and lower refractive anisotropy of the liquid crystal can be similar, thereby weakening the left and right butterfly unevenness and the upper and lower butterfly unevenness. .                     

Although described above with reference to the embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below. I can understand.

As described above, according to the present invention, the upper and lower or left and right cell gaps are adjusted differently by adjusting the thickness of the seal line member and the like, so that the left and right butterfly stains and the upper and lower butterfly stains generated in the liquid crystal display device employing the TN mode are removed. Can be weakened or eliminated.

In addition, in the prior art, the rubbing treatment was performed while the upper rubbing direction and the lower rubbing direction were 90 degrees (because of the TN mode). However, in the present invention, the inner angle of the upper rubbing direction and the lower rubbing direction is large in consideration of the lamp position. By making the outer shell in contact with the lamp small, the upper, lower, left and right retardation of the liquid crystal panel can be adjusted to weaken or remove the left and right butterfly stains and the upper and lower butterfly stains generated in the liquid crystal display device employing the TN mode.

In addition, according to the present invention, the arrangement of the lamps in the form of a direct type or a quadrangle reduces the left and right butterfly stains and upper and lower butterfly stains generated in the liquid crystal display device employing the TN mode by adjusting the left and right refractive index anisotropy (Δn). Or can be removed.

Claims (8)

A lamp for emitting light; And Δnd formed between a thin film transistor substrate, an opposing substrate facing the thin film transistor substrate, the thin film transistor substrate and the opposing substrate, and compensated in response to a temperature that increases as the lamp emits the light (wherein (DELTA) n includes a liquid crystal layer having a refractive index anisotropy of liquid crystal, and d is a cell gap of the liquid crystal, and includes a liquid crystal display panel displaying an image in response to the potential difference applied to the liquid crystal layer and the light; The lamp is arranged in at least one edge region of the thin film transistor substrate, a seal line member is formed in the edge region of the thin film transistor substrate and the opposing substrate to block the separation of the liquid crystal layer, And a separate layer corresponding to the edge area where the lamps are arranged. delete A lamp for emitting light; And Δnd formed between a thin film transistor substrate, an opposing substrate facing the thin film transistor substrate, the thin film transistor substrate and the opposing substrate, and compensated in response to a temperature that increases as the lamp emits the light (wherein (DELTA) n includes a liquid crystal layer having a refractive index anisotropy of liquid crystal, and d is a cell gap of the liquid crystal, and includes a liquid crystal display panel displaying an image in response to the potential difference applied to the liquid crystal layer and the light; And the lamps are arranged in a rectangular shape on each of edge regions of the thin film transistor substrate to compensate for Δnd of the liquid crystal layer. delete delete A lamp for emitting light; And Δnd formed between a thin film transistor substrate, an opposing substrate facing the thin film transistor substrate, the thin film transistor substrate and the opposing substrate, and compensated in response to a temperature that increases as the lamp emits the light (wherein (DELTA) n includes a liquid crystal layer having a refractive index anisotropy of liquid crystal, and d is a cell gap of the liquid crystal, and includes a liquid crystal display panel displaying an image in response to the potential difference applied to the liquid crystal layer and the light; A first polarizing plate having a transmission axis in a first direction is further provided on a rear surface of the thin film transistor substrate, and a second polarizing plate having a transmission axis in a second direction is further provided on an upper surface of the opposing substrate. The thin film transistor substrate may further include a first alignment layer rubbed in a first direction, and the opposing substrate may further include a second alignment layer rubbed in a second direction, and among the angles formed by the first direction and the second direction. An inner cabinet proximate to the lamp is large, and an outer cabinet oblique to the lamp is small. The liquid crystal display of claim 6, wherein the cabinet is larger than 90 degrees. The liquid crystal display of claim 6, wherein the liquid crystal layer is tilted smaller than 90 degrees.

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