KR20080058541A - Viewing angle control method of the patterned vertical alignment liquid crystal display - Google Patents

Abstract

A controllable viewing angle patterned vertical alignment LCD(Liquid Crystal Display) is provided to divide the area of a panel into an area for displaying a predetermined screen and an area for controlling a viewing angle. A lower substrate uses a transparent glass substrate or a plastic substrate. The first pixel electrode(15) is patterned to an upper partial area of the lower substrate at a constant angle. The second pixel electrode(15') is patterned on the remnant areas of the lower substrate toward left and right or up and down directions. A vertical alignment layer is located at the upper portion of the first and second pixel electrodes. A liquid crystal layer is arrayed vertically on the upper portion of the vertical alignment layer and has a negative permittivity anisotropy. The first common electrode is patterned on the lower portion of an upper substrate and has an electrode with the same size of the first pixel electrode. The second common electrode is formed on the remnant lower portion of the upper substrate by a plane shape and not separated from the first common electrode. A vertical alignment layer is located at the upper portion of the first and second common electrodes. Two pair of transistors are driven by two signal lines(11,11').

Description

Viewing angle control method of the patterned vertical alignment liquid crystal display}

FIG. 1A is a cross-sectional view illustrating a liquid crystal array state before voltage is applied to a patterned vertical alignment liquid crystal display device. FIG.

FIG. 1B is a cross-sectional view illustrating a liquid crystal array after voltage is applied in a patterned vertical alignment liquid crystal display device. FIG.

2 is a layout view of a liquid crystal display according to a first exemplary embodiment of the present invention.

3A, 3B, and 3C are layout views of liquid crystal display devices showing different structures of pixel electrodes for adjusting a viewing angle in FIG. 2.

FIG. 4A is a layout view of a pixel electrode in which a color filter is not formed in a portion for adjusting a viewing angle in the same electrode structure as that of Example 1 to produce white color; FIG.

FIG. 4B is a layout view of pixel electrodes showing that R (red), G (green), and B (blue) color filters are formed in a portion for adjusting the viewing angle in the same electrode structure as in Example 1. FIG.

5A and 5B are layout views of a liquid crystal display according to a second exemplary embodiment of the present invention.

FIG. 6A is a layout view of a pixel electrode in which white color is not formed in a portion for adjusting a viewing angle in the electrode structure as in Example 2; FIG.

FIG. 6B is a layout view of pixel electrodes showing that R, G, and B color filters are formed in a portion for adjusting a viewing angle in the same electrode structure as Example 2; FIG.

7A and 7B are layout views of a liquid crystal display according to a third exemplary embodiment of the present invention.

FIG. 8 is a layout view of a pixel electrode in which white is produced without forming a color filter in a portion for adjusting a viewing angle in an electrode structure as in Example 3; FIG.

The present invention is a device for adjusting the viewing angle of the liquid crystal display using the PVA mode.

Recently, the size of the liquid crystal display panel is changing from small to large in order to express more information, and thus efforts are being made to secure a viewing angle. Therefore, the focus has been on securing a wide viewing angle, and the PVA mode, which has a fast response rate, is one of them.

Here, the PVA mode liquid crystal display will be briefly described.

FIG. 1A is a cross-sectional view illustrating a liquid crystal array state before voltage application of a patterned vertically aligned liquid crystal display device, and FIG. 1B is a cross-sectional view illustrating a liquid crystal array state after voltage application of a patterned vertically aligned liquid crystal display device.

As shown in FIGS. 1A and 1B, in the vertically aligned liquid crystal display device, the common electrode 3 is patterned under the upper substrate 2, and the upper polarizer 1 is attached to the other side. The pixel electrode 6 is patterned on the lower substrate 5, the lower polarizer 7 is attached to the other side, and the liquid crystal layer 4 is injected between the two substrates.

Vertical alignment films (not shown) are applied to the upper and lower substrates 1 and 5 so as to face each other, and transmission axes of the polarizing plates 1 and 7 are attached to be perpendicular to each other, and an electric field is formed between the two substrates 1 and 5. A liquid crystal layer having negative dielectric anisotropy in which the long axis of the liquid crystal molecules is perpendicular to the direction of is injected.

The wide viewing angle characteristic is further improved by using a compensation film in the PVA mode driven by the vertical electric field.

 Conventional film-compensated patterned vertical alignment liquid crystal display devices are generated when the number and positions of negative C plates, positive A plates, and negative A plates are properly positioned on the upper and lower portions of the liquid crystal layer, thereby preventing conventional film compensation. The light leakage in the dark state according to the viewing angle is compensated by the compensation film, thereby minimizing the light leakage in the dark state. This realizes a liquid crystal display device having a better viewing angle characteristic than when only the PVA mode is used.

Specifically, the types and locations of compensation films are described in the Journal of display technology, Analytical Solutions Uniaxial-Film-Compensated Wide View Liquid Cystal Displays: Xinyu Xhu, Zhibing Ge and Shin Tson Wu, 2006, Vol. 2, No. 1, ISSN 1551-319X, pp. 2-20.

These conventional compensation films are described only as a focal point for obtaining wide viewing angle characteristics, and there is no information on whether they require different characteristics according to the use of the display.

Recently, a portable display such as a notebook computer or a mobile display has a wide viewing angle characteristic, so that personal information is leaked. Therefore, a wide viewing angle characteristic as well as a narrow viewing angle characteristic are required according to a user's convenience.

However, the viewing angle adjuster presented so far has a problem in that it is inferior in price competitiveness because it adjusts the viewing angle using two panels.

Accordingly, the present invention has been proposed to solve the above problems, and the liquid crystal display simultaneously displays the wide viewing angle and the narrow viewing angle at the same time by dividing the region for displaying a predetermined screen and the region for adjusting the viewing angle on one panel by patterning electrodes. The purpose is to provide a device.

In order to achieve the above object, the present invention forms a second common electrode using a plane transparent electrode without patterning a portion of a common electrode of a conventional PVA liquid crystal display, and forms a second common electrode on a lower substrate. It is characterized by controlling the direction of the liquid crystal display by adjusting the direction of the director of the liquid crystal by generating a vertical electric field by the two electrodes by patterning the electrode of the same size as the second pixel electrode in the left and right or up and down directions. do.

Further, in the present invention, the alignment state of the liquid crystal is a second common pixel for adjusting the viewing angle patterned in the right and left or up and down directions with the first pixel electrode and the first common electrode patterned in a predetermined direction for driving the pixel in the liquid crystal display device. Both the electrode and the second pixel electrode are vertically oriented, and the liquid crystal uses a liquid crystal having a negative dielectric anisotropy driven perpendicular to the direction of the electric field. Therefore, the first common electrode and the second common electrode are always of the same size because they are not separated. A voltage is applied and the voltage is applied to the first pixel electrode to lie the liquid crystal in a predetermined direction, thereby displaying the pixel, and the voltage is varied to the second pixel electrode to lie the liquid crystal director to the left and right or up and down directions as necessary, thereby reducing the viewing angle. Adjust In this case, when the voltage is not applied, there is a wide viewing angle characteristic, and when the voltage is applied, it is characterized by having a narrow viewing angle.

Further, in the present invention, in the case of the color filter, pixels displaying pixels are formed of R, G, and B, respectively, and a portion of the pixel for adjusting the viewing angle is not coated with a color filter or R, such as pixels displaying pixels. And a method for forming G, B. In this case, a black matrix is formed therebetween to cover a portion for adjusting the viewing angle, a boundary for displaying the pixel, and a boundary between the pixel and the pixel.

Hereinafter, the viewing angle adjustment of the PVA mode according to the present invention will be described in detail with reference to the accompanying drawings.

Example 1

Embodiment 1 is a liquid crystal display of PVA mode divided into an electrode for driving a viewing angle and an electrode for driving a pixel.

2 is a layout view showing the electrode structure of the PVA mode for adjusting the viewing angle according to the first embodiment of the present invention. As illustrated, the first pixel electrode 15, which is transparent to a part of the area, is patterned on a lower substrate using a transparent glass substrate or a plastic substrate to form a predetermined angle with the transmission axis direction of the lower polarizing plate, and the second pixel electrode that is transparent to the remaining area. 15 ') is patterned so that the liquid crystals lie down in the vertical direction when an electric field is applied, and signal lines 11 and 11' are applied to the gate electrode 12 to apply voltages separately to the electrodes for displaying the predetermined pixels and the electrodes for viewing angle adjustment. Two pairs of source / drain layers 13 and 13 ', respectively, in the same direction as the first pixel electrode in a portion of the same position as the first pixel electrode 15 below the upper substrate using the transparent glass substrate or the plastic substrate. The common electrode 14 is patterned to form the common electrode 14 in a plane form.

In the present invention, the liquid crystal uses negative dielectric anisotropy.

3A, 3B, and 3C are layout views of liquid crystal display devices showing different structures of pixel electrodes for adjusting a viewing angle in FIG. 2. As shown in FIG. 3, the electrode of the region displaying a predetermined pixel has the same shape as the electrode structure of FIG. 3 and variously forms the shape of the pixel electrode 15 ′ for adjusting the viewing angle so that the liquid crystal director can be driven without colliding with an electric field. Designed.

FIG. 4A is a layout view of pixel electrodes showing that a color filter is not formed at a portion for adjusting a viewing angle in the same electrode structure as that of Example 1. FIG. As shown in the drawing, R, G, and B color filters are formed in the area of the pixel 17 displaying a predetermined pixel, and the area of the pixel 18, which controls the viewing angle, is formed without white color filter to adjust the viewing angle. Since halftones can be displayed by varying the voltage of, the letters are overlapped or images are overlapped when the screen is viewed from the left and right directions.

FIG. 4B is a layout view of pixel electrodes showing that R, G, and B color filters are formed at portions of the electrode structure of Example 1 that adjust the viewing angle. As shown, R, G, and B color filters are formed in both the pixel 17 region displaying a predetermined pixel and the pixel 18 region adjusting the viewing angle to vary the voltage of the region adjusting the viewing angle. Because they can be displayed, the text is overlapped or the image is overlaid when viewing the screen from left to right.

In addition, the gate electrodes 12 are positioned between the two pixels to apply voltages separately to the electrodes displaying the predetermined pixels and the viewing angle adjusting electrodes, and two pairs of TFTs (thin film transistors) 16 and 16 'and a signal line are provided. (11, 11 '), respectively, and form a black matrix 19 to cover these parts.

Example 2

Unlike the first embodiment, the liquid crystal display which controls the viewing angle by patterning the second pixel electrode and the second common electrode in the horizontal and vertical directions by forming a part of the PVA liquid crystal display device to adjust the viewing angle in the horizontal direction is different from that in the first embodiment. Device.

5A and 5B are layout views of a liquid crystal display according to a second exemplary embodiment of the present invention. On the lower substrate using a transparent glass substrate or a plastic substrate, the transparent first pixel electrode 15 is patterned to form a predetermined angle with the transmission axis direction of the lower polarizing plate, and a region for adjusting the viewing angle in the horizontal direction is partially arranged in this region. The electrode is patterned so that the transparent second pixel electrode 15 'lies in the vertical direction when the liquid crystal applies an electric field, and the gate electrode 12 is applied to the electrode for displaying a predetermined pixel and to apply voltage separately to the electrode for viewing angle adjustment. The common electrode 14 has two pairs of signal lines 11 and 11 'and a source / drain layer 13 and 13', respectively, in the same direction as the first pixel electrode under the upper substrate using the transparent glass substrate or the plastic substrate. The common electrode 14 is patterned in the direction of patterning the second pixel electrode in a region for patterning the pattern and adjusting the viewing angle. Here, FIG. 5A is an electrode arrangement diagram which enlarges light leakage in the left and right directions to have narrow viewing angle characteristics, and FIG. 5B is an electrode arrangement diagram which enlarges light leakage in left and right and up to have narrow viewing angle characteristics.

FIG. 6A is a layout view of pixel electrodes showing that a color filter is not formed at a portion for adjusting a viewing angle in the electrode structure of the second embodiment. FIG. As shown in the drawing, R, G, and B color filters are formed in the area of the pixel 17 displaying a predetermined pixel, and the area of the pixel 18, which controls the viewing angle, is formed without white color filter to adjust the viewing angle. Since halftones can be displayed by varying the voltage of, the letters are overlapped or images are overlapped when the screen is viewed from the left and right directions.

FIG. 6B is a layout view of pixel electrodes showing that R, G, and B color filters are formed in a portion for adjusting a viewing angle in the same electrode structure as in Example 2. FIG. As shown, R, G, and B color filters are formed in both the pixel 17 region displaying a predetermined pixel and the pixel 18 region adjusting the viewing angle to vary the voltage of the region adjusting the viewing angle. Because they can be displayed, the text is overlapped or the image is overlaid when viewing the screen from left to right.

In addition, the signal line 11 is positioned between the two pixels so as to apply voltages separately to the electrodes displaying the predetermined pixels and the viewing angle adjusting electrodes, and the pair of TFTs 16 and 16 'and the gate electrodes 12 and 12' are positioned. And each form a black matrix 19 to cover these parts.

Example 3-

Unlike Embodiments 1 and 2, the third embodiment is a liquid crystal display for adjusting a viewing angle having four subpixels by attaching one pixel, which is a portion for adjusting the viewing angle, in the PVA liquid crystal display device.

7A and 7B are layout views of a liquid crystal display according to a third exemplary embodiment of the present invention. As shown in the drawing, the three sub-pixels displaying predetermined pixels on the lower substrate using the transparent glass substrate or the plastic substrate are patterned so that the transparent pixel electrode 15 is formed at a predetermined angle with the transmission axis direction of the lower polarizing plate, and the other sub The signal lines 11 and 11 'and the source / source are applied to the gate electrode 12 to pattern the pixel electrodes 15' in the left and right directions and the vertical direction and apply voltages separately to the electrodes for displaying the predetermined pixels and the viewing angle adjusting electrodes. The common electrode is disposed in the same direction as the pixel electrode 15 displaying the predetermined pixel in three subpixels having the drain layers 13 and 13 ', respectively, below the upper substrate using the transparent glass substrate or the plastic substrate and displaying the predetermined screen. One sub-pixel, which is an area for patterning (14) and adjusting the viewing angle, is common in the same direction as the patterned pixel electrode 15 'to adjust the viewing angle. The polar pattern (14 ').

Here, FIG. 7A illustrates that the electrode pattern of the attached sub-pixels has the narrow viewing angle characteristic in the left and right directions to adjust the viewing angle, and FIG. 7B forms the electrode so that the narrow viewing angle characteristic in the left and right and up and down.

FIG. 8 is a layout view of a pixel electrode in which white color is formed without forming a color filter in a portion for adjusting a viewing angle in the electrode structure of the third embodiment. As shown in the drawing, three subpixels 17 displaying a predetermined pixel form R, G, and B color filters, and the other one pixel 18 adjusting the viewing angle produces white color without forming a color filter. Since halftones can be displayed by varying the voltage of the area that adjusts the viewing angle, characters are overlapped or images are overlapped when viewing the screen in the left and right directions.

In addition, the gate electrodes 12, the TFTs 16 and 16 'and the signal lines 11 and 11' are respectively formed so as to apply voltages separately to the electrodes displaying the predetermined pixels and the viewing angle adjusting electrodes. To form a black matrix 19.

As described in detail above, the liquid crystal display device of the PVA mode for viewing angle adjustment according to the present invention has an electrode so as to lay the electrode differently when a liquid crystal direction self electric field is applied to a region for driving a pixel and a region for driving a viewing angle in one pixel. By patterning the voltage to the electrode portion to adjust the viewing angle can be appropriately implemented to implement a wide viewing angle and a narrow viewing angle. In addition, there is an advantage that the image is superimposed in the viewing angle direction by forming a color filter in the area displaying the viewing angle.

Claims (14)

Using PVA mode In the transparent electrode structure of the two layers of the thin film transistor, A lower substrate using a transparent glass substrate or a plastic substrate; A first pixel electrode patterned at a predetermined angle on a portion of an upper portion of the lower substrate; A second pixel electrode patterned in left, right, and up and down directions on the remaining area of the lower substrate; A vertical alignment layer on the first and second pixel electrodes; A liquid crystal layer having negatively aligned negative dielectric anisotropy positioned above the vertical alignment layer; Upper substrate: A first common electrode formed under the upper substrate by patterning an electrode having the same size as a first pixel electrode patterned on a portion of the lower substrate in the same direction; A second common electrode which is not separated from the first common electrode in a plane shape in the remaining portion of the lower portion of the upper substrate; A vertical alignment layer on the first and second common electrodes; A PVA liquid crystal display device which controls a viewing angle by applying different voltages to a viewing angle adjusting electrode and an electrode implementing a pixel by driving two pairs of transistors using two signal lines. The method of claim 1, A PVA liquid crystal display device which simultaneously controls the viewing angle in the left and right up and down directions by half-patterning the pixel electrodes in the region for controlling the viewing angle in the left and right directions and the up and down directions. The method according to claim 1 and 2, A PVA liquid crystal display device for adjusting an viewing angle without forming a color filter in a pixel portion for forming an R, G, B color filter and for adjusting a viewing angle. The method according to claim 1 and 2, PVA liquid crystal display device for adjusting the viewing angle in which the organic thin film is formed to correct the step without forming the color filter in the pixel portion for forming the R, G, B color filter and adjusting the viewing angle. The method according to claim 1 and 2, A PVA liquid crystal display device for controlling the viewing angle by forming R, G, B color filters on the image displaying portion and the pixel portion for adjusting the viewing angle to overlap the image in the viewing angle direction. Using PVA mode In the transparent electrode structure of the two layers of the thin film transistor, A lower substrate using a transparent glass substrate or a plastic substrate; A first pixel electrode patterned at a predetermined angle on the lower substrate; A second pixel electrode patterned in left, right, and up and down directions by placing a partial region next to the first pixel electrode on the lower substrate; A vertical alignment layer on the first and second pixel electrodes; A liquid crystal layer having negatively aligned negative dielectric anisotropy positioned above the vertical alignment layer; Upper substrate: A first common electrode formed under the upper substrate by patterning electrodes having the same size as the first pixel electrode patterned on the lower substrate in the same direction; A second common electrode which is not separated from the first common electrode patterned in the same direction at the same position as the region where the second pixel electrode is patterned under the upper substrate; A vertical alignment layer disposed below the first and second common electrodes; A PVA liquid crystal display device for controlling a viewing angle by applying two different voltages to a viewing angle adjusting electrode and an electrode implementing a pixel by driving two pairs of transistors using two gate electrodes. The method of claim 6, A PVA liquid crystal display device which simultaneously controls the viewing angle in the left and right up and down directions by half-patterning the pixel electrodes in the region for controlling the viewing angle in the left and right directions and the up and down directions. The method according to claim 6 and 7, A PVA liquid crystal display device for adjusting an viewing angle without forming a color filter in a pixel portion for forming an R, G, B color filter and for adjusting a viewing angle. The method according to claim 6 and 7, PVA liquid crystal display device for adjusting the viewing angle in which the organic thin film is formed to correct the step without forming the color filter in the pixel portion for forming the R, G, B color filter and adjusting the viewing angle. The method according to claim 6 and 7, A PVA liquid crystal display device for controlling the viewing angle by forming R, G, B color filters on the image displaying portion and the pixel portion for adjusting the viewing angle to overlap the image in the viewing angle direction. Using PVA mode with 4 sub pixels In the transparent electrode structure of the two layers of the thin film transistor, A lower substrate using a transparent glass substrate or a plastic substrate; A first pixel electrode patterned at a predetermined angle on three subpixels on the lower substrate; A second pixel electrode on the lower substrate, the second pixel electrode being patterned in left, right, and vertical directions on one sub-pixel; A vertical alignment layer on the first and second pixel electrodes; A liquid crystal layer having negatively aligned negative dielectric anisotropy positioned above the vertical alignment layer; Upper substrate: A first common electrode having three sub-pixels below the upper substrate patterned with electrodes having the same size as the first pixel electrode patterned on the lower substrate in the same direction; A second common electrode which is patterned in the same direction as the second pixel electrode in one sub-pixel under the upper substrate; A vertical alignment layer disposed below the first and second common electrodes; A PVA liquid crystal display device having one signal line per gate electrode and controlling a viewing angle by applying a different voltage to an electrode for implementing a viewing angle and an electrode for implementing a pixel for each subpixel. The method of claim 9, A PVA liquid crystal display device for controlling the viewing angle at the same time in the left and right directions by half-patterning the patterns of the pixel electrode and the common electrode in the left and right directions and the up and down directions on the pixel portion for adjusting the viewing angle. The method according to claim 11 and 12, A PVA liquid crystal display device for adjusting an viewing angle without forming a color filter in a pixel portion for forming an R, G, B color filter and for adjusting a viewing angle. The method according to claim 11 and 12, PVA liquid crystal display device for adjusting the viewing angle in which the organic thin film is formed to correct the step without forming the color filter in the pixel portion for forming the R, G, B color filter and adjusting the viewing angle.

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