KR100810302B1 - Viewing angle control method of the fringe-field switching liquid crystal display - Google Patents

Abstract

The present invention relates to a viewing angle control using a Prince-Field Switching (FFS) mode, and a method of patterning a general FFS electrode and a viewing angle control electrode separately is applied. In the electrode structure, a first common electrode is formed on an entire surface of a lower substrate, an insulating layer is covered thereon, and a plurality of first pixel electrodes parallel to each other are patterned to a partial region of the substrate, and the remaining regions are cylindrical electrodes, and the second pixel electrode Pattern. An upper substrate is formed to face the lower substrate, and a second common electrode is formed in a portion of the substrate facing the second pixel electrode. By applying a constant voltage of the same magnitude to the first common electrode and the second common electrode of the liquid crystal display device and applying a different voltage to the first pixel electrode, the voltage generated between the first common electrode and the first pixel electrode is generated. By implementing a liquid crystal display by a Prince electric field and by adjusting the voltage on the second pixel electrode, a wide viewing angle or a narrow viewing angle can be appropriately adjusted by the vertical electric field generated by the voltage difference between the second pixel electrode and the second common electrode.

fringe-field switching, wide viewing angle, narrow viewing angle

Description

Viewing angle control method of the fringe-field switching liquid crystal display}

1 is a layout view of the electrode structure of the FFS mode according to the first embodiment of the present invention

2 is a cross-sectional view showing the horizontal arrangement of the liquid crystal having the electrode structure of FIG.

FIG. 3 is a layout view of an electrode structure in an FFS mode in which only the rubbing direction of liquid crystal differs from that of FIG.

4 is a cross-sectional view showing the hybrid arrangement of liquid crystals having the electrode structure of FIG.

5 is a layout view of the electrode structure of the FFS mode according to a second embodiment of the present invention

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

In general, the size of the liquid crystal display panel is changing from small to large, and thus efforts are being made to secure a viewing angle. There are various types of modes used in the liquid crystal display. Among them, liquid crystal modes having wide viewing angle characteristics include (IPS) In-Plan Switching and FFS modes driven by a horizontal electric field. In the IPS mode, since the liquid crystal molecules rotate in one direction parallel to the substrate, the viewing angle is superior to the Twist Nematic mode, but the light efficiency is lowered at the upper part of the electrode, the driving voltage is high, and color display problems exist depending on the viewing angle. The high-opening IPS structure was adopted to improve the transmittance, and the electrode structure was wedge-shaped to improve the color problem. FFS mode has been proposed to remedy various problems with IPS.

In the FFS mode, since the common electrode and the pixel electrode are transparent electrodes, there is a disadvantage in that the mask surface is increased by one than the conventional TN. However, since the liquid crystal molecules were rotated almost parallel to the substrate by the strong fringe electric field in the entire area above the electrode, the wide viewing angle, high transmittance, and low driving voltage were simultaneously achieved. However, securing the viewing angle of the liquid crystal display may have a positive result. However, when performing work while carrying a laptop computer, securing a sufficient viewing angle causes a problem of leakage of personal information and invasion of privacy.

An object of the present invention relates to a liquid crystal display which can be adjusted to a wide viewing angle and a narrow viewing angle according to a user's use in order to solve the problems in the conventional liquid crystal display for the conventional wide viewing angle as described above.

In order to achieve the above object, in the present invention, a portion of the pixel electrode of the conventional FFS liquid crystal display is not patterned in a lattice pattern, but the second pixel electrode is formed on the upper substrate by using a plane-type transparent electrode. It is characterized by controlling the viewing angle 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 when the voltage is applied by patterning the electrode having the same size as the two pixel electrode as the second common electrode in the plane shape. do.

Further, in the present invention, the alignment state of the liquid crystal is horizontal in both the lattice-shaped first pixel electrode and the first common electrode portion and the viewing angle adjustment second common electrode and the second pixel electrode portion in the liquid crystal display device. As the oriented structure, the two electrode portions for visual field adjustment when voltage is applied use a liquid crystal having a positive dielectric anisotropy that causes a vertical electric field to cause the liquid crystal director to have an inclination angle. In this case, when the voltage is not applied, a wide viewing angle is applied, and when the voltage is applied, it has a narrow viewing angle.

Further, in the present invention, the alignment state of the liquid crystal is a structure in which the second common electrode and the second pixel electrode portion for adjusting the viewing angle of the liquid crystal display are vertically oriented at one portion and horizontally oriented at the other, and for driving the pixels. The grid-shaped first pixel electrode and the first common electrode part are horizontally oriented in the upper and lower substrates. The two electrode parts for adjusting the viewing angle when voltage is applied generate a vertical electric field so that the liquid crystal director is driven perpendicular to the electric field direction and parallel to the substrate. It uses negative dielectric anisotropy that can be laid down. In this case, when the voltage is not applied, it has a narrow viewing angle, and when the voltage is applied, it has a wide viewing angle.

Further, in the present invention, the first pixel electrode of the lattice shape of the FFS electrode structure is patterned in the longitudinal direction, and the second pixel electrode and the second common electrode for viewing angle adjustment are positioned at the lower part of the pixel in a part of the pixel. It features.

Hereinafter, the viewing angle adjustment of the FFS 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 FFS mode divided into an electrode for viewing angle adjustment and an electrode for driving a pixel.

1 is a layout view showing the electrode structure of the FFS mode for adjusting the viewing angle according to the first embodiment of the present invention. As shown in the drawing, the first common electrode 1 is patterned in a plane shape on a lower substrate using a transparent glass substrate or a plastic substrate, and two gate electrodes 6 are connected to one gate electrode 6 in order to apply voltage separately to the viewing angle adjusting electrode. With two signal lines 5 and 5 'and a source / drain layer 7 and 7', some areas on the first common electrode are patterned with a lattice-shaped transparent first pixel electrode 2, and some other areas Pattern the transparent second pixel electrode 3 in a plane shape, and pattern the transparent second common electrode 4 in a plane shape in a portion below the upper substrate at the same position as the second pixel electrode 3. The gate electrode is covered by a black matrix (BM) 8.

In the present invention, the liquid crystal uses positive dielectric anisotropy, the electrode width of the lattice-shaped first pixel electrode is 1 to 5 mu m, and the interval between the electrode and the electrode is 1 to 6 mu m.

FIG. 2 is a cross-sectional view of FIG. 1, in which the alignment layer 10 below the upper substrate and the alignment layer 11 above the lower substrate use a horizontal alignment layer so that the liquid crystal 9 is arranged horizontally on the substrate.

FIG. 3 is a layout view of the electrode structure of the FFS mode in which only the rubbing direction of the liquid crystal differs from the structure of FIG. 1. As shown, the electrode structure is the same as that of FIG. 1, the rubbing direction is parallel to the electrode direction of the signal line, and the liquid crystal uses negative dielectric anisotropy.

4 is a cross-sectional view illustrating the hybrid arrangement of liquid crystals having the electrode structure of FIG. 3. In the alignment layer 10 under the upper substrate, a portion of the substrate is vertically aligned, the remaining region of the substrate is horizontally aligned, and the alignment layer 11 on the lower substrate is horizontally aligned, so that the liquid crystal 9 is hybridly aligned.

Example 2

Unlike the first embodiment, the second embodiment has a structure in which the first pixel electrode is vertically patterned and the viewing angle adjusting electrode is disposed in a partial region of the lower part of the pixel in the FFS liquid crystal display device.

5 is a layout view of the electrode structure of the FFS mode according to the second embodiment of the present invention. As shown in the drawing, the transparent first common electrode 1 is patterned in a plane shape on a lower substrate using a transparent glass substrate or a plastic substrate, and gate electrodes 6 and 6 'are applied to apply a voltage separately to the viewing angle adjusting electrode. ) Two, one signal line (5) and two source / drain layers (7, 7 '), and the patterned second pixel electrode (2) in a lattice pattern on the first common electrode, and the rest of the area The area is patterned by a transparent second pixel electrode 3 in the form of a plane, and the second common electrode 4 in the form of a plane is formed in a partial area under the upper substrate at the same position as the second pixel electrode 3. Pattern and mask the gate electrode with a black matrix (BM) (8).

In addition, in the present invention, the liquid crystal uses positive dielectric anisotropy when the liquid crystal alignment structure of FIG. 2 is used, and negative dielectric anisotropy when the liquid crystal alignment structure of FIG. 4 is used.

In the present invention, the electrode width of the lattice-shaped first pixel electrode is 1 to 5 mu m, and the interval between the electrode and the electrode is 1 to 6 mu m.

In the liquid crystal display of the FFS mode for viewing angle adjustment according to the present invention, the electrode is placed in a region for driving a pixel and a region for driving a viewing angle differently in one pixel, so that the region for driving the viewing angle using two transistors is a vertical electric field. The region driving the pixel can realize a wide viewing angle and a narrow viewing angle appropriately by using a fringe electric field.

Claims (4)

Using FFS 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 common electrode patterned in a plane shape on the lower substrate; An insulating layer disposed between the first common electrode and the first and second pixel electrodes; A first pixel electrode patterned on a portion of the insulating layer in a horizontal direction in a lattice shape with an electrode width of 1 to 5 μm, and an interval between electrodes being 1 to 6 μm; A second pixel electrode patterned in a plane shape on the remaining area of the insulating layer; A horizontally arranged liquid crystal layer disposed on the first and second pixel electrodes; An upper substrate; A second common electrode formed by patterning an electrode having a plane shape having the same size as a second pixel electrode patterned in a plane shape on a portion of the lower substrate under the upper substrate; The liquid crystal has positive dielectric anisotropy; A fringe field switching liquid crystal display device in which a viewing angle is adjusted by applying different voltages to the viewing angle adjusting electrode and the pixel implementing electrode by using two signal lines or driving two transistors using two gate electrodes. In claim 1, In the orientation of the liquid crystal layer, The orientation of the liquid crystals of the second common electrode and the second pixel electrode, which are the electrodes for adjusting the viewing angle, has a structure in which one part of the liquid crystal is arranged horizontally and the other part is arranged vertically; The alignment of the liquid crystals of the first common electrode and the first pixel electrode of the electrode for driving the pixels are both horizontally aligned; A fringe field switching liquid crystal display device in which a liquid crystal adjusts a viewing angle having negative dielectric anisotropy. Using FFS 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 common electrode patterned in a plane shape on the lower substrate; An insulating layer disposed between the first common electrode and the first and second pixel electrodes; A first pixel electrode patterned in a lattice shape on a portion of the upper part of the insulating layer in a lattice shape with an electrode width of 1 to 5 μm, and an interval between electrodes being 1 to 6 μm; A second pixel electrode patterned in a plane shape on the remaining area of the insulating layer; A horizontally arranged liquid crystal layer disposed on the first and second pixel electrodes; An upper substrate; A second common electrode formed by patterning an electrode having a plane shape having the same size as a second pixel electrode patterned in a plane shape on a portion of the lower substrate under the upper substrate; The liquid crystal has positive dielectric anisotropy; A fringe field switching liquid crystal display device in which a viewing angle is adjusted by applying different voltages to the viewing angle adjusting electrode and the pixel implementing electrode by using two signal lines or driving two transistors using two gate electrodes. In claim 3, In the orientation of the liquid crystal layer, The orientation of the liquid crystals of the second common electrode and the second pixel electrode, which are the electrodes for adjusting the viewing angle, has a structure in which one part of the liquid crystal is arranged horizontally and the other part is arranged vertically; The alignment of the liquid crystals of the first common electrode and the first pixel electrode of the electrode for driving the pixels are both horizontally aligned; A fringe field switching liquid crystal display device in which a liquid crystal adjusts a viewing angle having negative dielectric anisotropy.

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