KR101308353B1 - liquid crystal display device and method of fabricating the same - Google Patents

Abstract

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

The liquid crystal display according to the present invention comprises a first substrate, a second substrate, and a liquid crystal layer interposed therebetween, and includes a red sub-pixel (Pr) and a green sub-pixel; Pg), a blue sub-pixel (Pb), a viewing angle controlling sub-pixel (Pv), and the red subpixel (Pr), green subpixel (Pg), and blue sub The pixel Pb and the view control subpixel Pv are driven in a vertical alignment (VA) method. In the liquid crystal display according to the present invention, the red subpixel Pr, the green subpixel Pg, and the blue subpixel Pb have a 4 domain structure, and the view control subpixel Pv has a 2 domain structure. It is characterized by.

The present invention can be implemented by selecting a wide viewing angle mode or a narrow viewing angle mode in a multi-domain vertical alignment (VA) mode liquid crystal display device that implements a wide viewing angle, thereby securing individual security.

Vertical Orientation, Multi Domain, Field of View Control

Description

Liquid crystal display device and method of manufacturing the same {liquid crystal display device and method of fabricating the same}

1 is a cross-sectional view illustrating a liquid crystal display device capable of operating in a conventional wide viewing angle mode and a narrow viewing angle mode.

2 is a plan view showing a pixel of a liquid crystal display as a first embodiment according to the present invention;

3 is a plan view illustrating a second substrate corresponding to a pixel of the liquid crystal display of FIG. 2.

4 is a cross-sectional view taken along the line II ′ of FIGS. 2 and 3.

5A and 5B are graphs showing transmission characteristics in the wide viewing angle mode of the present invention.

FIG. 6 is a graph showing contrast-ratio according to viewing angle in a subpixel Pv for viewing control in the wide viewing angle mode in the liquid crystal display according to the present invention. FIG.

7A is a graph showing transmission characteristics when no voltage is applied to the red, green, and blue subpixels Pr, Pg, and Pb in the narrow viewing angle mode.

7B is a graph showing transmission characteristics of the subpixel Pv for view control in the narrow viewing angle mode.

FIG. 8 is a graph illustrating contrast-ratio according to a viewing angle in a subpixel for controlling a field of view in a narrow viewing angle mode in the liquid crystal display according to the present invention. FIG.

9 is a sectional view showing a pixel of a liquid crystal display as a second embodiment according to the present invention;

10 is a graph showing a change in luminance curve according to an increase in a cell gap of a visual control subpixel in the liquid crystal display according to the present invention.

Fig. 11 is a sectional view showing a pixel of a liquid crystal display as a third embodiment according to the present invention.

12 is a plan view showing a pixel of a liquid crystal display as a fourth embodiment according to the present invention;

Description of the Related Art [0002]

100, 200, 300: first substrate 123: gate electrode

125, 225, 325, 425: gate wiring 129, 229, 329: gate insulating film

131: semiconductor layer 135: source electrode

137: drain electrode 139, 439: data wiring

145, 245, 345: protective films 161, 261, 361, 461: first pixel electrode

162, 262, 362, 462: second pixel electrode 170, 270, 370: liquid crystal layer

180, 280, 380: second substrate 181, 281, 381: black matrix

182, 282, 382: color filter layers 185, 285, 385: common electrode

191, 291, 391: first polarizing plate 192, 292, 392: second polarizing plate

383: white color filter layer 488a: rib pattern

488b: Bar Pattern

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

Recently, a liquid crystal display device, which is one of the flat panel display devices that are continuously attracting attention, is a device for changing optical anisotropy by applying an electric field to a liquid crystal having both liquidity and optical properties of crystals. Compared with the low power consumption, small volume, large size, and high definition, it is widely used.

The liquid crystal display device has various modes depending on the nature of the liquid crystal and the structure of the pattern.

Specifically, TN mode (Twisted Nematic Mode) for arranging the liquid crystal directors to be twisted by 90 ° and controlling voltage by applying a voltage, and dividing one pixel into several domains to change the field of view angle of each domain. Multi-domain mode that realizes wide viewing angle, OCB mode (Optically Compensated Birefringence Mode) that compensates for the phase change of light according to the direction of light by attaching a compensation film to the outer peripheral surface of the substrate, and on one substrate In-plane switching mode in which two electrodes are formed in the liquid crystal to twist in parallel planes of the alignment layer, and a long axis of the liquid crystal molecules is vertically aligned with the alignment layer plane using a negative type liquid crystal and a vertical alignment layer. VA mode (Vertical Alignment) is various.

Until recently, studies have been actively conducted to have a wide viewing angle as much as possible, but recently, researches on liquid crystal displays having a narrow viewing angle as well as a wide viewing angle have been actively conducted.

For example, if a liquid crystal display device is used to protect company secrets, state secrets, or privacy, a wide viewing angle may cause information to be leaked or invaded by people in adjacent locations.

For this reason, in recent years, technologies for controlling the liquid crystal display device to view the liquid crystal display device at a desired viewing angle when desired are actively studied.

1 is a cross-sectional view illustrating a liquid crystal display device that may operate in a conventional wide viewing angle mode and a narrow viewing angle mode.

As shown in FIG. 1, the liquid crystal display device driven in the conventional wide viewing angle mode and the narrow viewing angle mode is formed by combining the first liquid crystal panel 11 and the second liquid crystal panel 12.

The first liquid crystal panel 11 is bonded to the first substrate 10 and the second substrate 20 so as to face each other and spaced apart from each other, and between the first substrate 10 and the second substrate 20. The first liquid crystal layer 30 is formed.

Although not shown, a thin film transistor TFT and a pixel electrode may be formed on an inner surface of the first substrate 10, and a color filter and a common electrode may be formed on an inner surface of the second substrate 20.

The second liquid crystal panel 12 is formed on the outer surface of the second substrate 20.

The second liquid crystal panel 12 is bonded to the third substrate 50 and the fourth substrate 60 so as to face each other and spaced apart from each other, and between the third substrate 50 and the fourth substrate 60. The second liquid crystal layer 70 is formed.

Although not shown, first and second electrodes are formed on inner surfaces of the third and fourth substrates 50 and 60, respectively, and the first and second electrodes are used to apply an electric field to the second liquid crystal layer 70. It is connected to a predetermined control unit.

The second liquid crystal layer 70 is aligned horizontally or vertically by an applied electric field.

A first polarizing plate 81 is formed on an outer surface of the first substrate 10 of the first liquid crystal panel 11, and a first polarizing plate 81 is formed on the outer surface of the fourth substrate 60 of the second liquid crystal panel 12. 2 polarizing plates 82 are formed.

At least one polarizer may be further provided between the first liquid crystal panel 11 and the second liquid crystal panel 12.

When driving the wide viewing angle mode, the second liquid crystal panel 12 passes an image made from the first liquid crystal panel 11 as an electric field is applied or not applied to the second liquid crystal layer 70.

When driving the narrow viewing angle mode, the second liquid crystal panel 12 passes a light processed from the second liquid crystal panel 12 only in a predetermined direction by applying or applying a predetermined electric field. Thus, an image made from the first liquid crystal panel 11 and passed through the second liquid crystal panel 12 is visible only in a specific narrow field of view.

As described above, when the viewing angle control liquid crystal panel is attached on the main liquid crystal panel providing the main image in order to control the viewing angle of the conventional liquid crystal display device, not only the viewing angle control liquid crystal panel should be additionally manufactured but also the thickness and weight of the product. Will be more than doubled.

In addition, when the viewing angle control liquid crystal panel and the main liquid crystal panel is bonded, misalignment may occur. When using the wide viewing angle mode, light incident from a backlight must always pass through the viewing angle control liquid crystal panel, so that the front luminance is significantly lowered. There is this.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same, which can view a screen having excellent image quality even at a wide viewing angle, and can view the screen only at a narrow viewing angle according to selection.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a first substrate and a second substrate on which first to fourth subpixel regions are defined; A liquid crystal layer interposed between the first substrate and the second substrate, the liquid crystal layer having a negative dielectric constant and having liquid crystal molecules arranged vertically with respect to the first substrate; First to fourth thin film transistors formed in the first to fourth subpixel regions on the first substrate; First to fourth pixel electrodes electrically connected to the first to fourth thin film transistors; A color filter layer formed on an area of a second substrate corresponding to the first to third subpixel areas; A common electrode formed on the entire surface of the second substrate; A first pattern formed on the second substrate in the first to third subpixel regions and tilting the liquid crystal molecules in at least four directions; And a second pattern formed on the second substrate in the fourth subpixel region, and tilting the liquid crystal molecules in at least two directions.

In order to achieve the above object, a method of manufacturing a liquid crystal display according to the present invention may include preparing a first substrate and a second substrate on which first to fourth subpixel regions are defined; Forming first to fourth thin film transistors in the first to fourth subpixel regions on the first substrate; Forming first to fourth pixel electrodes electrically connected to the first to fourth thin film transistors; Forming a color filter layer on a region of a second substrate corresponding to the first to third subpixel regions; Forming a first pattern on the second substrate in the first to third subpixel regions to tilt the liquid crystal molecules in at least four directions; And forming a second pattern on the second substrate in the fourth subpixel region to tilt the liquid crystal molecules in at least two directions.

The liquid crystal display according to the present invention comprises a first substrate, a second substrate, and a liquid crystal layer interposed therebetween, and includes a red sub-pixel (Pr) and a green sub-pixel; Pg), a blue sub-pixel (Pb), and a viewing angle controlling sub-pixel (Pv).

The red subpixel Pr, the green subpixel Pg, and the blue subpixel Pb each have red, green, and blue color filters, and the visual control subpixel Pv does not have a color filter. Or a white color color filter.

The red subpixel Pr, the green subpixel Pg, the blue subpixel Pb, and the view control subpixel Pv are driven in a vertical alignment (VA) method.

In the liquid crystal display according to the present invention, the red subpixel Pr, the green subpixel Pg, and the blue subpixel Pb have a 4 domain structure, and the view control subpixel Pv has a 2 domain structure. .

That is, the red, green, and blue subpixels are vertically aligned with a multi-domain structure for a wide viewing angle, and the subpixels for viewing control are inclined so that liquid crystals lie up and down to cause light leakage in the left and right side fields. It is a vertical alignment with a two domain structure.

 The liquid crystal display according to the present invention can switch between the narrow viewing angle mode and the wide viewing angle mode by controlling the visual control subpixel Pv in on-state and off-state. .

The liquid crystal display according to the present invention may have various arrangements with respect to the arrangement order of the red, green, and blue subpixels Pr, Pg, and Pb and the visual control subpixel Pv. The blue subpixels Pr, Pg, and Pb and the subpixel Pv for view control may be arranged in a quad type arranged in two rows or two columns or a stripe type arranged in a row.

The present invention provides the user with resilience to the security range, can be used not only for one person, but also when using more than one person can see the screen in high quality without inconvenience and secure security.

Hereinafter, a liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a plan view showing a pixel of the liquid crystal display as a first embodiment according to the present invention, and FIG. 3 is a plan view showing a second substrate corresponding to the pixel of the liquid crystal display of FIG. 4 is a cross-sectional view taken along the line II ′ of FIGS. 2 and 3.

2 to 4, the liquid crystal display according to the present invention includes red, green, and blue subpixels Pr, Pg, and Pb and a view control subpixel Pv. The subpixels Pr, Pg, and Pb and the subpixel Pv for view control are driven in a vertical alignment (VA) method.

In the liquid crystal layers of the red, green, and blue subpixels Pr, Pg, and Pb and the field control subpixel Pv, the long axis of the liquid crystal molecules is vertically aligned with respect to the substrate before an electric field is applied.

The liquid crystal layer 170 is made of a nematic liquid crystal, and is made of liquid crystal molecules having negative dielectric anisotropy.

The liquid crystal display according to the present invention includes a first control unit for driving the red, green, and blue subpixels Pr, Pg, and Pb, and a second control unit for driving the view control subpixel Pv. .

The sub-pixel Pv for controlling the field of view may be switched to the narrow viewing angle mode and the wide viewing angle mode through the second control unit.

The red subpixel Pr, the green subpixel Pg, and the blue subpixel Pb have a 4 domain structure, and the view control subpixel Pv has a 2 domain structure.

The cell gap d2 of the field control subpixel Pv may be larger than the cell gap d1 of the red, green, and blue subpixels Pr, Pg, and Pb.

The red, green, and blue subpixels Pr, Pg, and Pb may be formed in a PVA method and an MVA method to implement a wide viewing angle in the wide viewing angle mode.

The patterned vertical alignment (PVA) method is a method of realizing a multi-domain by distorting an electric field by forming a common electrode or a pixel electrode having a predetermined pattern in one subpixel, and arranging the alignment of liquid crystal molecules perpendicular to a substrate. By applying voltage to the pixel electrode and the common electrode, the liquid crystal molecules are freely laid in various directions so that they have the same viewing angle characteristics in any direction.

The MVA (Multidomain Vertical Alignment) method is a method of attaching a dielectric protrusion or rib to one substrate to incline the vertically aligned liquid crystal molecules and to incline the liquid crystal molecules in an inclined direction when voltage is applied.

The vertical alignment mode liquid crystal display according to the present invention may be applied to both the PVA method, the MVA method, and the like.

When the visual field control subpixel Pv is in an off-state, the liquid crystal display is driven in a wide viewing angle mode to display an image implemented by the red, green, and blue subpixels Pr, Pg, and Pb. You can see high quality images from a wide viewing angle.

Here, the off state of the field control subpixel Pv means that the field control subpixel Pv is not driven.

Since the liquid crystal molecules are vertically arranged on the substrate and the first and second polarizers are vertically intersected before the field control subpixel Pv is formed, the field control subpixel Pv is dark. Since the image quality is not affected by the driving of the red, green, and blue subpixels Pr, Pg, and Pb on the screen, the screen can be viewed at a wide viewing angle.

When the field of view control subpixel Pv is in an on-state, the liquid crystal display is driven in a narrow viewing angle mode and light passing through the field of view control subpixel Pv is affected by the birefringence effect of the liquid crystal. Since it acts as a light leakage at the side viewing angle, the image implemented by the red, green, and blue subpixels Pr, Pg, and Pb can be seen with high quality only at a narrow viewing angle, for example, a front viewing angle.

When the visual field control subpixel Pv is turned on, the visual field control subpixel Pv is driven.

When the electric field is formed between the pixel electrodes of the first and second substrates and the common electrode, the visual control subpixel Pv is twisted so that the liquid crystal molecules are perpendicular to the shape of the electric field according to the property of the liquid crystal having negative dielectric anisotropy. . Since the liquid crystal molecules are rod-shaped, the refractive indexes of the long axis and the short axis are different from each other, so that when the liquid crystal molecules are arranged perpendicular to the electric field, light is transmitted laterally through the liquid crystal molecules to act as side light leakage. Therefore, the image quality displayed by the driving of the red, green, and blue subpixels Pr, Pg, and Pb on the screen greatly affects the side image quality, so that the screen can be seen with excellent image quality only at the front narrow viewing angle.

The viewing angle range may be adjusted by adjusting the voltage applied to the view control subpixel Pv.

A first polarizing plate 191 having a first transmission axis is formed on an outer surface of the first substrate 100, and a second polarizing plate 192 having a second transmission axis is formed on an outer surface of the second substrate 180. Formed.

Preferably, the first transmission axis and the second transmission axis are perpendicular to each other.

As shown in FIG. 2 and FIG. 4, the first substrate 100 of the liquid crystal display according to the present invention crosses the plurality of gate lines 125 and the gate lines 125 arranged in a line. The subpixels Pr, Pg, Pb, and Pv are defined by the plurality of data lines 139.

The gate wiring 125 may include copper (Cu), aluminum (Al), an aluminum alloy (eg, AlNd), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), and molybdenum-tungsten. At least one selected from the group of metals consisting of (MoW).

The gate wiring 125 may have a multiple wiring structure in which at least one metal layer is stacked.

The data line 139 may include copper (Cu), aluminum (Al), an aluminum alloy (eg, AlNd), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta), and molybdenum-tungsten. At least one selected from the group of metals consisting of (MoW).

Among the subpixels, each of the red, green, and blue subpixels Pr, Pg, and Pb is formed at an intersection point of the gate line 125 and the data line 139 to switch voltages. Thin film transistors T1, T2, and T3 and first pixel electrodes 161 connected to the thin film transistors T1, T2, and T3 are provided.

Of the subpixels, the subpixel Pv for view control is formed at the intersection of the gate line 125 and the data line 139 to connect a fourth thin film transistor T4 for switching a voltage, and is connected to the fourth thin film transistor. And a second pixel electrode 162 formed in the field control subpixel Pv.

The second pixel electrode 162 has a long slit s in a predetermined direction, here a first direction.

The slit (s) serves to allow the vertically aligned liquid crystal molecules to lie in a predetermined direction when driven.

The first pixel electrode 161 and the second pixel electrode 162 are a transparent metal made of indium tin oxide (ITO) and indium zinc oxide (IZO). At least one selected from the group.

The thin film transistor includes a gate electrode 123 protruding from the gate line 125, a gate insulating layer 129 formed on the entire surface of the first substrate 100 on which the gate electrode 123 is formed, and the gate electrode 123. The semiconductor layer 131 in which amorphous silicon (a-Si) and amorphous silicon (n + a-Si) ion-implanted with impurities are stacked on the upper gate insulating layer 129 and branched from the data line 139. A source electrode 135 formed at one end of the semiconductor layer 131 and a drain electrode 137 formed at the other end of the semiconductor layer 131 are spaced apart from the source electrode 135.

A passivation layer 145 is formed on the first substrate 100 to cover the thin film transistor, and the passivation layer 145 may include a first contact hole 153a and a portion exposing a portion of the drain electrode 137. Two contact holes 153b are formed.

The first pixel electrode 161 is connected to the drain electrode 137 through the first contact hole 153a, and the second pixel electrode 162 is connected to the second contact hole 153b. It is connected to the drain electrode 137.

A gate insulating layer 129 is interposed between the gate line 125 and the data line 139.

The gate insulating layer 129 includes at least one selected from the group of inorganic insulating materials including silicon nitride (SiNx) and silicon oxide (SiOx).

The passivation layer 145 includes at least one selected from the group of inorganic insulating materials including silicon nitride (SiNx) and silicon oxide (SiOx).

In addition, the passivation layer 145 may include at least one selected from the group of organic insulating materials including benzocyclobutene (BCB) and acrylic (Acryl) -based materials.

Since the color filter layer is not formed in the field control subpixel Pv, the cell gap d2 of the field control subpixel is smaller than the cell gap d1 of the red, green, and blue subpixels Pr, Pg, and Pb. It may be as large as the filter layer.

As shown in FIGS. 3 and 4, the second substrate 180 on which the black matrix 181 and the color filter layer 182 are formed is opposite to the first substrate 100, and the second substrate 180 is opposite to the second substrate 180. The common electrode 185 is formed at 180.

A black matrix 181 is formed on the second substrate 180 to block the thin film transistor (TFT) region, the gate wiring 125, the data wiring 139, and the light leakage generating region around the thin film transistor (TFT) region. do.

The black matrix 181 may be formed using, for example, a metal such as chromium oxide (CrOx) or chromium (Cr) having an optical density of 3.5 or more, or an organic material based on carbon.

In the red subpixel Pr on the second substrate 180, a red color filter 182 containing a pigment for implementing a red color is formed.

The green subpixel Pg on the second substrate 180 is formed with a green color filter 182 containing a pigment that realizes a green color.

A blue color filter 182 containing a pigment for implementing a blue color is formed in the blue subpixel Pb on the second substrate 180.

A white color filter made of a transparent insulating material may be formed in the field control subpixel Pv on the second substrate 180, or a color filter may not be formed in the field control subpixel Pv. .

An overcoat layer for planarizing the surface may or may not be formed on the entire surface of the second substrate 180.

The common electrode 185 is formed on the entire surface of the second substrate 180 including the red, green, and blue subpixels Pr, Pg, and Pb and the field control subpixel Pv.

The common electrode 185 includes at least one selected from the group of transparent metals consisting of indium tin oxide (ITO) and indium zinc oxide (IZO).

A protrusion 188a is formed on the common electrode 185 of the red, green, and blue subpixels Pr, Pg, and Pb to distort an electric field to implement a multi-domain effect. The protrusion 188a may be a dielectric.

The projections 188a are vertically oriented liquid crystal molecules 171 positioned at the center portion of the subpixel and are arranged to be slightly tilted toward the projections 188a. When the electric field is generated, the liquid crystal molecules 171 the projections. Tilt toward 188a to rearrange perpendicular to the electric field.

That is, the viewing angle characteristic is improved by the long axis of the liquid crystal molecules 171 lying radially from the projection 188a from the center.

The protrusions 188a may be provided one by one corresponding to the centers of the red, green, and blue subpixels Pr, Pg, and Pb, and may be formed at least one at a predetermined interval within the subpixels.

In addition, the protrusion 188a may be formed not only of circular protrusions but also of polygonal protrusions, and may have a rib shape to allow the liquid crystal molecules 171 to lie down with various orientations when an electric field is applied.

On the common electrode 185 of the field control subpixel Pv, a long bar pattern 188b is formed in the first direction to maximize the field control effect.

The first direction may be parallel to or perpendicular to the first transmission axis of the first polarizer 191.

The first direction may be parallel or perpendicular to the second transmission axis of the second polarizing plate 192.

As a result, the liquid crystal molecules of the visual control subpixel Pv are laid down in a direction perpendicular to the first direction when an electric field is applied to the liquid crystal layer 170 by the bar pattern 188b formed in the first direction. Can cause light leakage in the right field of view.

For example, if the bar pattern 188b long in the first direction is formed to be left and right in the front viewing angle, the liquid crystal molecules lie up and down with respect to the front viewing angle when the electric field is applied, thereby viewing angle characteristics with respect to the upper and lower viewing angles. However, the left and right viewing angles are improved, but retardation is greatly generated and the contrast is reduced, resulting in poor viewing angle characteristics.

The red, green, and blue subpixels Pr, Pg, and Pb may drive the liquid crystal molecules in various directions when driving the liquid crystal by the protrusions 188a, thereby implementing a multi-domain effect.

The field control subpixel Pv is formed by the liquid crystal molecules driven by the slit s in the first direction of the second pixel electrode 162 of the first substrate 100 and the rod pattern 188b in the first direction. Since the light leakage may be induced at the left and right viewing angles by driving in a direction perpendicular to the first direction, the wide viewing angle mode and the narrow viewing angle mode may be selectively implemented by controlling the driving of the viewing control subpixel Pv.

Referring to FIG. 4, a first polarizer 191 is disposed on an outer surface of the first substrate 100 of the liquid crystal display, and a second polarizer 192 is disposed on an outer surface of the second substrate 180. It is.

It is preferable that the first polarizing plate 191 has a first transmission axis, the second polarizing plate 192 has a second transmission axis, and the directions of the first transmission axis and the second transmission axis are perpendicular to each other.

The first transmission axis of the first polarizing plate 191 is parallel or perpendicular to a first direction that is a long direction of the bar pattern 188b of the visual control subpixel Pv.

When driving in the wide viewing angle mode, the field control subpixel Pv of the liquid crystal display is not driven, and a black voltage is applied or no voltage is applied to the second pixel electrode 162 of the field control subpixel Pv. It becomes black.

That is, the liquid crystal molecules 171 are arranged perpendicular to the substrate and are perpendicular to the first transmission axis of the first polarizing plate 191 and the second transmission axis of the second polarizing plate 192. When the pixel Pv is not driven, light is blocked by the second polarizer 192 to be in a black state.

When driving in the narrow viewing angle mode, the field control subpixel Pv of the liquid crystal display is driven, and a proper voltage is applied to the second pixel electrode 162 of the field control subpixel Pv, and the field control subpixel Pv is driven. As a vertical electric field is generated in the liquid crystal layer 170 disposed at (Pv) and the vertically arranged liquid crystal molecules 171 are laid down in a direction perpendicular to the first direction of the bar pattern 188b, the front side is applied to voltage application. Regardless, the black state is maintained, and since the phase delay of the light occurs due to the birefringence of the liquid crystal molecules 171 at the inclination angle, light leakage occurs at the left and right viewing angles.

That is, when a predetermined voltage is applied to the second pixel electrode 162 and a vertical electric field is generated between the second pixel electrode 162 and the common electrode 185, the liquid crystal molecules 171 lie in a predetermined direction. The light passing through the first transmission axis of the first polarizing plate 191 is phase delayed by the liquid crystal molecules and passes through the second transmission axis of the second polarizing plate 192.

Although not shown, the liquid crystal display according to the present invention may include a first control unit for driving the red, green, and blue subpixels Pr, Pg, and Pb to provide a desired image and the subpixel Pv for view control. And a second control unit for viewing the image only at a desired viewing angle.

The second controller may adjust the range of the viewing angle by adjusting the intensity of the electric field applied to the visual control subpixel Pv.

The projections 188a formed on the red, green, and blue subpixels Pr, Pg, and Pb and the bar pattern 188b formed on the view control subpixel Pv are formed in the same process.

Since the color filter layer is not formed in the viewing angle control subpixel Pv, the height from the first substrate 100 to the rod pattern 188b and the projection from the first substrate 100 to the protrusion 188a. The height can be the same.

As another example, the bar pattern 188b and the protrusion 188a may have the same height from the second substrate 180.

5A and 5B are graphs showing transmission characteristics in the wide viewing angle mode of the present invention.

FIG. 6 is a graph showing contrast ratios according to viewing angles in the subpixel Pv for viewing control in the wide viewing angle mode in the liquid crystal display according to the present invention.

FIG. 5A is a graph illustrating transmission characteristics when no voltage is applied to the red, green, and blue subpixels Pr, Pg, and Pb in the wide viewing angle mode, and FIG. 5B is a view control subpixel Pv in the wide viewing angle mode. Is a graph showing the permeation characteristics of

As shown, in the wide viewing angle mode, the visual control subpixel Pv is always black because the transmittance is close to 0%, and on-off of the red, green, and blue subpixels Pr, Pg, and Pb is performed. The transmittance characteristic of the state is black when the voltage is not applied and the transmittance is close to 0%, and when the voltage is applied, the screen is uniformly white in the entire state.

In addition, in the wide viewing angle mode, the contrast ratio is also uniform and good in the whole field of view, which is referred to the graph shown in FIG. 6.

FIG. 7A is a graph showing transmission characteristics when no voltage is applied to the red, green, and blue subpixels Pr, Pg, and Pb in the narrow viewing angle mode, and FIG. 7B is a subpixel Pv for controlling the view in the narrow viewing angle mode. Is a graph showing the permeation characteristics of

FIG. 8 is a graph showing contrast-ratios according to viewing angles in the subpixels for viewing control in the narrow viewing angle mode in the liquid crystal display according to the present invention.

In the liquid crystal display device driven in the narrow viewing angle mode, a vertical electric field is formed between the common electrode and the second pixel electrode in the visual control subpixel Pv, and the liquid crystal molecules initially arranged vertically are arranged while lying perpendicular to the electric field. .

Since the slit s and the bar pattern 188b formed in the viewing control subpixel Pv are formed parallel to or perpendicular to the first transmission axis, the light passing through the viewing control subpixel Pv has a transmittance from the side. Will be higher.

As shown in FIGS. 7A and 7B, between the common electrode 185 of the red, green, and blue subpixels Pr, Pg, and Pb and the first pixel electrode 161 in a voltage off-state. Since no electric field is formed in the liquid crystal molecules 171 aligned between the common electrode 185 and the first pixel electrode 161, the liquid crystal molecules 171 do not move in the initial vertically arranged state and thus are represented in a normally black mode. do.

In the red, green, and blue subpixels Pr, Pg, and Pb in a voltage applied state, an electric field is formed between the common electrode 185 and the first pixel electrode 161, so that the common electrode 185 is formed. ) And the long axis of the liquid crystal molecules 171 vertically oriented between the first pixel electrode 161 are arranged perpendicular to the electric field.

Therefore, the front viewing angle is generally white, but in the left and right viewing angle directions, the retardation is largely generated by the liquid crystal molecules 171 lying in the visual control subpixel Pv, thereby reducing the contrast. As a result, the left and right viewing angles become worse and have a narrower viewing angle.

As shown in FIG. 8, in the liquid crystal display according to the present invention, retardation is largely generated by the liquid crystal molecules 171 in the view control subpixel Pv in the left and right viewing angle directions in the narrow viewing angle mode. The color contrast ratio is reduced and the color contrast ratio is improved only at the frontal viewing angle.

When the voltage applied to the visual field control subpixel Pv is properly adjusted during narrow viewing angle driving, the intensity of the electric field formed between the common electrode 185 and the second pixel electrode 162 can be adjusted. Since the retardation values in the left and right viewing angle directions of the liquid crystal molecules 171 may be adjusted, the range of the narrow viewing angle may be adjusted.

This provides the users of the liquid crystal display with resilience to the security range, and can be used as a single person, and even when using more than one person by adjusting to the desired viewing angle range to ensure high-definition security without inconvenience You can do it.

Meanwhile, the liquid crystal display according to the present invention may have various arrangements with respect to the arrangement order of the red, green, and blue subpixels Pr, Pg, and Pb and the subpixel Pv for view control. The green and blue subpixels Pr, Pg, and Pb and the visual control subpixels Pv may be arranged horizontally, and the arrangement order may be randomly arranged.

9 is a cross-sectional view illustrating a pixel of a liquid crystal display as a second embodiment according to the present invention.

Here, the structures of the green subpixel Pg and the view control subpixel Pv of the liquid crystal display according to the second exemplary embodiment of the present invention will be described, and detailed descriptions of the same parts as those of FIG. 4 will be omitted.

As illustrated in FIG. 9, a hole h is formed in the center of the color filter layer 282 on the second substrate 280 of the green subpixel Pg.

That is, the holes h are formed in the color filter layer 282, and the liquid crystal molecules 271 oriented perpendicular to the substrate are slightly tilted toward the holes h, and when the electric field is generated, the liquid crystal molecules 271 is inclined toward the hole h and rearranges perpendicularly to the electric field.

That is, the viewing angle characteristic is improved by the long axis of the liquid crystal molecules 271 lying in the radial shape from the center of the hole h.

The holes h may be provided one by one corresponding to the centers of the red, green, and blue subpixels Pr, Pg, and Pb, and at least one hole may be formed at predetermined intervals in the subpixels.

In addition, the hole h may not only be formed in a circular shape, but may be formed in various shapes, and may be formed to be long so that the liquid crystal molecules 271 may lie down with various orientations when an electric field is applied.

The second pixel electrode 262 corresponding to the view control subpixel Pv on the first substrate 200 has a first slit S1 elongated in a first direction to form the second pixel electrode 162. Split into at least two regions.

A second slit S2 elongated in the first direction is formed in the common electrode 285 corresponding to the view control subpixel Pv on the second substrate 280.

The second slit S2 is formed parallel to the first slit S1 along the center of the region of the second pixel electrode 262 divided by the first slit S1.

In one embodiment, only one of the first slit S1 of the second pixel electrode 262 and the second slit S2 of the common electrode 285 may be formed.

The first direction may be parallel to or perpendicular to a first transmission axis of the first polarizing plate 291 disposed outside the first substrate 200.

The first direction may be parallel or perpendicular to a second transmission axis of the second polarizing plate 292 disposed outside the second substrate 280.

The first transmission axis of the first polarizing plate 291 is parallel or perpendicular to the first direction that is the long direction of the first slit S1 and the second slit S2 of the visual control subpixel Pv.

As a result, the liquid crystal molecules of the visual control subpixel Pv are laid down in a direction perpendicular to the first direction when an electric field is applied to the liquid crystal layer 270 by the second slit S2 formed in the first direction. This can cause light leakage in the right field of view.

According to the second embodiment of the present invention, a separate process for forming protrusions or rib patterns is not necessary, and holes are formed by removing a predetermined region of the color filter layer, or slits are formed at predetermined positions of the common electrode to vertically align. Aroma can be provided to a type liquid crystal molecule.

FIG. 10 is a graph illustrating a change in luminance curve according to an increase in a cell gap of a visual control subpixel in the liquid crystal display according to the present invention.

Here, the overcoat layer is not formed on the second substrate 200, and the white color filter layer is not formed corresponding to the view control subpixel Pv on the second substrate 200. The cell gap d2 of Pv is larger than the cell gap d1 of the red, green, and blue subpixels Pr, Pg, and Pb.

For example, the cell gap d2 of the visual control subpixel Pv may be larger than the cell gap d1 of the red, green, and blue subpixels Pr, Pg, and Pb by the thickness of the color filter layer 282. .

As the cell gap d2 of the visual field control subpixel Pv increases, the luminance curve moves in the direction of the arrow of the graph.

That is, the cell gap d2 of the field control subpixel Pv is red, green, and blue subpixels Pr, Pg, and Pb when the field control subpixel Pv is driven to be in the narrow viewing angle mode. If it is larger than), the maximum value of luminance is further increased at left and right viewing angles. Therefore, the image quality is further deteriorated at the left and right viewing angles, thereby improving security.

The vertical alignment mode liquid crystal display according to the present invention may be applied to both a PVA method, an MVA method, and the like.

The visual control subpixel Pv includes a first slit S1 in a first direction of the second pixel electrode 262 formed on the first substrate 200 and a common electrode formed on the second substrate 280. Since the liquid crystal molecules 271 are driven in a direction perpendicular to the first direction when the liquid crystal is driven by the second slit S2 in the first direction of 285, light leakage may be induced at left and right viewing angles. The wide viewing angle mode and the narrow viewing angle mode may be selectively implemented by controlling the driving of the subpixel Pv.

When driving in the wide viewing angle mode, the field control subpixel Pv of the liquid crystal display is not driven, and a black voltage is applied or no voltage is applied to the second pixel electrode 262 of the field control subpixel Pv. It becomes black.

That is, the liquid crystal molecules 271 are arranged perpendicular to the substrate and are perpendicular to the first transmission axis of the first polarizing plate 291 and the second transmission axis of the second polarizing plate 292. When the pixel Pv is not driven, light is blocked by the second polarizer 292 to become a black state.

When driving in the narrow viewing angle mode, the field control subpixel Pv of the liquid crystal display is driven, and an appropriate voltage is applied to the second pixel electrode 262 of the field control subpixel Pv, and the field control subpixel Pv is driven. As a vertical electric field is generated in the liquid crystal layer 270 disposed in the Pv, the vertically aligned liquid crystal molecules 271 lie in a direction perpendicular to the first direction of the second slit S2, thereby applying voltage from the front side. Irrespective of the black state, the phase delay of the light occurs due to the birefringence of the liquid crystal molecules 271 at the inclination angle, so light leakage occurs at the left and right viewing angles.

That is, when a predetermined voltage is applied to the second pixel electrode 262 and a vertical electric field is generated between the second pixel electrode 262 and the common electrode 285, the liquid crystal molecules 271 lie in a predetermined direction. And the light passing through the first transmission axis of the first polarizing plate 291 is delayed by the liquid crystal molecules 271 and passes through the second transmission axis of the second polarizing plate 292, and is observed as light leakage at the side viewing angle. .

Although not shown, the liquid crystal display according to the present invention may include a first control unit for driving the red, green, and blue subpixels Pr, Pg, and Pb to provide a desired image, and the subpixel Pv for view control. And a second control unit for driving the image to view the image only at a desired viewing angle.

The sub-pixel Pv for controlling the field of view may be switched to the narrow viewing angle mode and the wide viewing angle mode through the second control unit.

The second controller may adjust the range of the viewing angle by adjusting the intensity of the electric field applied to the visual control subpixel Pv.

11 is a cross-sectional view illustrating a pixel of a liquid crystal display as a third embodiment according to the present invention.

Here, the detailed description of the same parts as in FIGS. 4 and 9 will be omitted.

As illustrated in FIG. 11, a green color filter layer 382 is formed on the second substrate 300 of the green subpixel Pg of the liquid crystal display according to the present invention, and the subpixel Pv for view control is formed. The white color filter layer 383 is formed on the second substrate 380.

A hole h is formed in the central portion of the green color filter layer Pg formed on the second substrate 380 of the green subpixel Pg to tilt the liquid crystal molecules 371 in multiple directions.

The hole h is driven while the liquid crystal molecules 371 arranged between the first substrate 300 and the second substrate 380 of the green subpixel Pg radially lie about the hole h. To be possible.

A first slit S1 is formed in the second pixel electrode 362 formed on the first substrate 300 of the field control subpixel Pv.

A second slit S2 for tilting the liquid crystal molecules 371 is formed at the center of the white color filter layer 383 formed on the second substrate 380 of the view control subpixel Pv.

The second slit S2 is formed by removing the white color filter 383.

The second slit S2 divides the view control subpixel Pv on the second substrate 380 into at least one area.

The second slit S2 may be formed to cross the subpixel Pv for controlling the field of view on the second substrate 380.

The first slit S1 and the second slit S2 are formed in the same direction.

The hole h formed in the green color filter layer 382 is to lay the liquid crystal molecules 371 radially to improve viewing angle characteristics.

 The first liquid crystal molecules 371 of the visual control subpixel Pv are applied when the electric field is applied to the liquid crystal layer 370 by the first and second slits S1 and S2 formed in a first direction crossing the subpixels. Lying in the direction perpendicular to the direction can cause light leakage in the left and right viewing angles.

The field control subpixel Pv is formed in the first slit S1 in the first direction of the second pixel electrode 362 of the first substrate 300 and the common electrode 385 of the second substrate 380. Since the liquid crystal molecules 371 are driven in a direction perpendicular to the first direction when the liquid crystal is driven by the second slit S2 in the first direction, light leakage may be induced at the left and right viewing angles, thereby controlling the subpixel Pv for the field control. By controlling the driving of), wide viewing angle mode and narrow viewing angle mode can be selectively implemented.

12 is a cross-sectional view illustrating a pixel of a liquid crystal display as a fourth embodiment according to the present invention.

Here, the detailed description of the same parts as in FIGS. 4 and 9 will be omitted.

As illustrated in FIG. 12, the pixel of the liquid crystal display according to the present invention includes red, green, and blue subpixels Pr, Pg, and Pb defined by crossing the gate line 425 and the data line 439. And a subpixel Pv for visual field control, and are driven in a VA manner.

A first slit S1 having a bent structure is formed in the first pixel electrode 461 of the first substrate corresponding to the red, green, and blue subpixels Pr, Pg, and Pb, and is formed on the common electrode of the second substrate. A rib pattern 488a having a bent structure is formed on it to form a four-domain (A, B, C, D) structure having different driving directions of the liquid crystal molecules.

Instead of the rib pattern 488a, a slit pattern may be formed on the common electrode of the second substrate corresponding to the red, green, and blue subpixels Pr, Pg, and Pb.

In addition, a white color filter layer may be formed on the second substrate corresponding to the view control subpixel Pv instead of the rib pattern 488a, and a groove or a slit pattern may be formed in the white color filter layer in a bent structure. It may be.

The first slit S1 and the rib pattern 488a of the bending structure are bent from the second direction to the third direction, and the second direction and the third direction are preferably perpendicular to each other, but are not limited thereto. no.

Red, green, and blue color filter layers are formed on the second substrate corresponding to the red, green, and blue subpixels Pr, Pg, and Pb.

A white color filter layer may or may not be formed on the second substrate corresponding to the viewing control subpixel Pv.

In addition, at least one rib pattern or second slit S2 is formed in the second pixel electrode 162 of the first substrate corresponding to the view control subpixel Pv in the first direction crossing the subpixel. At least one bar pattern 488b is formed in the first direction on the common electrode of the second substrate corresponding to the viewing control subpixel Pv.

The visual control subpixel Pv forms a two-domain (E, F) structure in which the driving direction of the liquid crystal molecules is opposite.

In addition, instead of the bar pattern 488b, a slit pattern may be formed to extend in the first direction on the common electrode 485.

In addition, a white color filter layer is formed on the second substrate corresponding to the visual field control subpixel Pv instead of the bar pattern 488b, and a groove or a slit pattern is formed in the white color filter layer to be long in the first direction. It may be formed.

The first direction may be left and right directions in a front viewing angle.

The first direction may be parallel to or perpendicular to a first transmission axis of the first polarizing plate disposed outside the first substrate.

The first direction may be parallel or perpendicular to a second transmission axis of the second polarizing plate disposed outside the second substrate.

The first transmission axis of the first polarizing plate is parallel or perpendicular to the first direction that is the long direction of the second slit S2 or the bar pattern 488b of the visual control subpixel Pv.

As a result, the liquid crystal molecules of the visual control subpixel Pv are laid down in the direction perpendicular to the first direction by the bar pattern 488b formed in the first direction when an electric field is applied to the liquid crystal layer. May cause light leakage.

The rib pattern 488a and the first slit S1 are formed while being bent in the second direction to the third direction and in the third direction to the second direction.

The second direction is inclined at 45 ° with respect to the first transmission axis of the first polarizing plate, and the third direction is inclined at 135 ° with respect to the first transmission axis.

The second direction may be inclined at 45 ° with respect to the second transmission axis of the second polarizing plate, and the third direction may be inclined at 135 ° with respect to the second transmission axis.

The rib pattern 488a and the first slit S1 determine a direction in which the liquid crystal molecules vertically arranged in the subpixels are laid down upon application of an electric field, and have four-domain (A, B,, C, D) structures. By forming, the liquid crystal molecules are driven while lying in different directions in the four domains to implement a wide viewing angle.

When driving in the narrow viewing angle mode, the field control subpixel Pv of the liquid crystal display is driven, and an appropriate voltage is applied to the second pixel electrode 462 of the field control subpixel Pv, and the field control subpixel Pv is driven. As a vertical electric field is generated in the liquid crystal layer disposed at (Pv) and the vertically aligned liquid crystal molecules are laid down in a direction perpendicular to the first direction of the bar pattern 488b, the front side maintains a black state regardless of voltage application. At the inclination angle, light retardation occurs due to birefringence of the liquid crystal molecules, and light leakage occurs at the left and right viewing angles.

That is, when a predetermined voltage is applied to the second pixel electrode 462 and a vertical electric field is generated between the second pixel electrode 462 and the common electrode, the liquid crystal molecules lie in a predetermined direction, and the first polarizing plate The light passing through the first transmission axis of the phase is delayed by the liquid crystal molecules and passes through the second transmission axis of the second polarizing plate, so it is observed as light leakage at the side viewing angle.

When the voltage applied to the visual field control subpixel Pv is properly adjusted during narrow viewing angle driving, the intensity of the electric field formed between the common electrode and the second pixel electrode can be adjusted, and thus the left and right sides of the liquid crystal molecules are adjusted. Since the retardation value in the viewing angle direction can be adjusted, the range of narrow viewing angle can be adjusted.

This provides the users of the liquid crystal display with resilience to the security range, can be used for one person, and even when using more than one person by adjusting to the desired viewing angle range to ensure high-definition security without discomfort You can do it.

Meanwhile, the liquid crystal display according to the present invention may have various arrangements with respect to the arrangement order of the red, green, and blue subpixels Pr, Pg, and Pb and the subpixel Pv for view control. The green and blue subpixels Pr, Pg, and Pb and the visual control subpixels Pv may be arranged horizontally, and the arrangement order may be randomly arranged.

Although the present invention has been described in detail through specific embodiments, it is intended to describe the present invention in detail, and the liquid crystal display and its manufacturing method according to the present invention are not limited thereto. It is apparent that modifications and improvements are possible to those skilled in the art.

The present invention can be implemented by selecting a wide viewing angle mode or a narrow viewing angle mode in a multi-domain vertical alignment (VA) mode liquid crystal display which implements a wide viewing angle, and thus has a first effect of securing individual security.

In addition, the present invention has a second effect in which the process is simple by adding a subpixel for view control in the liquid crystal panel to control the viewing angle.

In addition, the present invention has a third effect of providing a thin and light liquid crystal display device having excellent light efficiency since there is no need to add a separate view control layer.

In addition, the present invention provides a user with resilience to the security range, and can be used not only for one person, but also when using more than one person can view the screen in high quality without inconvenience and secure a security It works.

Claims (23)

A first substrate and a second substrate on which first to fourth subpixel regions are defined; A liquid crystal layer interposed between the first substrate and the second substrate, the liquid crystal layer having a negative dielectric constant and having liquid crystal molecules arranged vertically with respect to the first substrate; First to fourth thin film transistors formed in the first to fourth subpixel regions on the first substrate; First to fourth pixel electrodes electrically connected to the first to fourth thin film transistors; A color filter layer formed on an area of a second substrate corresponding to the first to third subpixel areas; A common electrode formed on the entire surface of the second substrate; A first pattern formed on the second substrate in the first to third subpixel regions and tilting the liquid crystal molecules in at least four directions; And And a second pattern formed on the second substrate in the fourth subpixel region, the second pattern tilting the liquid crystal molecules in at least two directions. The method of claim 1, And the first pattern is a hole pattern formed in the color filter layer. The method of claim 1, And the first pattern is a dielectric protrusion. The method of claim 1, And the first pattern is at least one rib pattern having at least one bending structure in the first to third subpixel regions. The method of claim 1, And the second pattern is at least one bar pattern crossing the fourth subpixel area. The method of claim 1, And the second pattern is formed on the common electrode, and is at least one slit pattern crossing the fourth subpixel area. The method of claim 1, And a white color filter layer further formed on the second substrate to correspond to the fourth subpixel area. 8. The method of claim 7, And the second pattern is at least one slit pattern crossing the fourth subpixel area in the white color filter layer. The method of claim 1, And the fourth pixel electrode has at least one or more slit patterns along the long direction of the second pattern. The method of claim 1, A first polarizer disposed on an outer surface of the first substrate; and Further comprising a second polarizing plate disposed on the outer surface of the second substrate, The first transmission axis of the first polarizing plate and the second transmission axis of the second polarizing plate are perpendicular to each other. The method of claim 10, And the first transmission axis coincides with the long direction of the second pattern. The method of claim 10, And the first transmission axis is perpendicular to the long direction of the second pattern. The method of claim 1, The cell gap of the fourth subpixel region is larger than the cell gap of the first to third subpixel regions by the thickness of the color filter layer. Forming a first substrate and a second substrate; Interposing a liquid crystal layer having a negative dielectric constant between the first substrate and the second substrate and having liquid crystal molecules vertically aligned with respect to the first substrate; And Bonding the first substrate and the second substrate to each other with the liquid crystal layer interposed therebetween; Forming the first substrate and the second substrate, Preparing a first substrate and a second substrate on which first to fourth subpixel regions are defined; Forming first to fourth thin film transistors in the first to fourth subpixel regions on the first substrate; Forming first to fourth pixel electrodes electrically connected to the first to fourth thin film transistors; Forming a color filter layer on a region of a second substrate corresponding to the first to third subpixel regions; Forming a first pattern on the second substrate in the first to third subpixel regions to tilt the liquid crystal molecules in at least four directions; And And forming a second pattern of tilting the liquid crystal molecules in at least two directions on the second substrate of the fourth subpixel region. delete 15. The method of claim 14, In the forming of the first pattern, Forming a hole pattern on the color filter layer, the manufacturing method of the liquid crystal display device. 15. The method of claim 14, In the forming of the first pattern, A method of manufacturing a liquid crystal display device, wherein a dielectric protrusion is formed on the second substrate. 15. The method of claim 14, In the forming of the first pattern, And forming at least one rib pattern having at least one bending structure in the first to third subpixel regions. 15. The method of claim 14, In the forming of the second pattern, And forming at least one bar pattern across the fourth subpixel region. 15. The method of claim 14, In the forming of the second pattern, And forming a common electrode having at least one slit pattern across the fourth subpixel region on the second substrate. 15. The method of claim 14, And forming a white color filter layer corresponding to the fourth subpixel area on the second substrate. 15. The method of claim 14, In the forming of the second pattern, And forming a white color filter layer having at least one slit pattern across the fourth subpixel region in a region corresponding to the fourth subpixel region on the second substrate. 15. The method of claim 14, In the forming of the fourth pixel electrode, And forming at least one slit pattern along the long direction of the second pattern on the fourth pixel electrode.

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