KR20080049440A - Liquid crystal display controllable viewing angle and driving method thereof - Google Patents

Abstract

An LCD(Liquid Crystal Display) capable of controlling a polar angle and a driving method thereof are provided to control blocking/transmission of light and polar angle characteristics and control wide/narrow polar angle modes without loss of resolution by applying a passive barrier to an LC panel and efficiently controlling a signal applied to the LC panel. In an LC panel(110), plural pixels are arranged in matrix. Each of the plural pixels has a quad structure comprising neighboring RGB(Red, Green and Blue) color pixels(B) and a control pixel(C). A pixel barrier(120) is disposed in an upper part of the LC panel, and is formed in an area corresponding to the control pixel. A backlight assembly(130) is disposed in a lower part of the LC panel, and supplies light to the LC panel. The RGB color pixels operates in the ECB(Electrically Controlled Birefringence) mode, and the control pixel operates in the IPS(In-Plain Switching) mode.

Description

Liquid crystal display device capable of viewing angle control and driving method thereof {Liquid crystal display controllable viewing angle and driving method}

1 and 2 are diagrams illustrating a liquid crystal display according to the related art.

3 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

4 is a plan view of FIG. 3 seen from the front and side.

FIG. 5 is a model diagram illustrating the wide viewing angle mode and the narrow viewing angle mode of FIG. 3.

6 and 7 are graphs showing the viewing angle characteristics of FIG. 3.

FIG. 8 is a graph illustrating a change in luminance according to a viewing angle in the narrow viewing angle mode of FIG. 3.

9 is a graph illustrating a contrast ratio according to a viewing angle in FIG. 3.

FIG. 10 is a model diagram for describing an efficient driving method of FIG. 3.

FIG. 11 is a model diagram for embodying the structure of FIG. 3. FIG.

12 is a flowchart illustrating a method of driving a liquid crystal display according to an exemplary embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

110: liquid crystal panel 120: pixel barrier

130: backlight assembly R, G, B: color pixels

C: control pixel

The present invention relates to a liquid crystal display device and a manufacturing method thereof, and more particularly, to a liquid crystal display device capable of viewing angle control and a manufacturing method thereof.

The liquid crystal display device forms a liquid crystal layer having anisotropic dielectric constant between upper and lower substrates, which are transparent insulating substrates, and then adjusts the intensity of the electric field formed in the liquid crystal layer to change the molecular arrangement of the liquid crystal material, thereby A display device expresses a desired image by adjusting the amount of light transmitted through a color filter substrate.

FIG. 1 and FIG. 2 are schematic diagrams of a liquid crystal display according to the related art. In particular, FIGS. 1 and 2 illustrate a case in which a liquid crystal display having a view angle control mode is driven in a wide viewing angle mode and a narrow viewing angle mode, respectively. .

Basic principles of the viewing angle control method shown in FIGS. 1 and 2 are as follows.

First, a liquid crystal panel having a transverse electric field structure having a wide viewing angle is configured for image display, a liquid crystal panel for adjusting the viewing angle is added to the upper or lower portion of the liquid crystal panel, and then the added liquid crystal panel is driven to narrow the wide viewing angle. To adjust the viewing angle mode. The liquid crystal panel added to adjust the viewing angle basically has a function of not inhibiting the wide viewing angle characteristic of the liquid crystal panel displaying an image and inducing a narrow viewing angle necessary for security or privacy aspects.

1 and 2, the liquid crystal panel including the first liquid crystal layer 80 is a panel for adjusting the viewing angle, and the liquid crystal panel including the second liquid crystal layer 90 is a panel for displaying an image to have a wide viewing angle. . If no voltage is applied to the first liquid crystal layer 80, the liquid crystal molecules 81 are arranged in parallel between the two substrates 10 and 21 to maintain the original wide viewing angle, thereby forming a wide viewing angle mode. When voltage is applied to the 80, the liquid crystal molecules 81 are arranged vertically between the two substrates 10 and 21, and thus the viewing angle is reduced, thereby entering the narrow viewing angle mode.

1 and 2, the first, second, third, and fourth substrates 10, 21, 22, and 30 are disposed in parallel to each other, and the first substrate 10 and the second substrate 21 are arranged in parallel. Transparent electrodes 70 and 60 are formed to face each other on the inner surface of each other, and two linear electrodes 40 and 50 are formed parallel to each other on the upper surface of the third substrate 22.

The first and second liquid crystal layers 80 and 90 are formed between the first substrate 10, the second substrate 21, the third substrate 22, and the fourth substrate 30, respectively.

The liquid crystal panel including the first and second substrates 10 and 21 and the first liquid crystal layer 80 between the two substrates 10 and 21 is a viewing angle control liquid crystal panel capable of adjusting a wide viewing angle and a narrow viewing angle. .

In the state in which no electric field is applied, as shown in FIG. 1, the liquid crystal molecules 81 of the first liquid crystal layer 80 are aligned parallel to the first and second substrates 10 and 21. In the wide viewing angle mode shown in FIG. 1, since the liquid crystal molecules 91 of the second liquid crystal layer 90 are also aligned in the same direction, the liquid crystal molecules 91 have the same viewing angle as that of the liquid crystal display having a general transverse electric field structure having one liquid crystal panel. It does not affect other characteristics of the transverse electric field structure.

On the outer surfaces of the first substrate 10 and the third substrate 30, two polarizing plates 11 and 31 are respectively attached to polarize the light passing therethrough. At this time, the transmission axis directions of the polarizing plates 11 and 31 are arranged to be perpendicular or parallel to the alignment direction of the liquid crystal molecules 81 and 91.

FIG. 2 illustrates a case where the liquid crystal display of FIG. 1 is used in the narrow viewing angle mode.

When a voltage is applied to the two transparent electrodes 70 and 60 to form an electric field in the vertical direction between the first and second substrates 10 and 21, the liquid crystal molecules 81 of the first liquid crystal layer 80 are filled with the electric field. Are arranged perpendicular to the two substrates 10 and 21 along the direction of. In this case, the liquid crystal molecules 82 adjacent to the two substrates 10 and 21 are arranged in parallel to the two substrates 10 and 21 because the orientation force due to rubbing is greater than the force exerted by the electric field.

In this narrow viewing angle mode, the liquid crystal molecules 81 arranged perpendicular to the two substrates 10 and 21 do not affect the retardation of light traveling to the front of the two substrates 10 and 21.

However, as the polarized light passes through the first liquid crystal layer 80 made of the liquid crystal molecules 81, the polarization state is changed by a delay. The rain decreases and the viewing angle becomes narrower.

That is, by applying an electric field to the first liquid crystal layer 80 added for the purpose of controlling the viewing angle, the viewing angle of the liquid crystal display is lowered to narrow the viewing angle.

As described above, since the narrow viewing angle and the wide viewing angle mode may be switched through one liquid crystal display, a flexible viewing angle characteristic may be exhibited as needed.

However, when the viewing angle characteristic of the liquid crystal display device is adjusted through such a structure, a separate liquid crystal panel for adjusting the viewing angle is used in addition to the liquid crystal panel displaying an image.

Therefore, the overall thickness of the liquid crystal display device is excessively increased, resulting in additional costs and manufacturing processes, making it difficult to perform processes such as rubbing, scribing, and bonding the substrate, and unnecessary power consumption. There is an increasing problem.

Accordingly, the technical problem to be achieved by the present invention is a liquid crystal display device which can control light blocking / transmission and viewing angle characteristics within a range in which a manufacturing process is easier and a cost is reduced as compared to a method using a double liquid crystal panel, and its It is to provide a driving method.

Another object of the present invention is to apply a passive barrier (Passive barrier) to the liquid crystal panel and to efficiently control the signal applied to the liquid crystal panel, a liquid crystal display device that can control the wide / narrow viewing angle mode without loss of resolution And a driving method thereof.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

In the liquid crystal display according to the present invention for achieving the above technical problem, a plurality of pixels are arranged in a matrix form, and each of the plurality of pixels includes a quad of red, green, and blue color pixels and control pixels adjacent to each other. A liquid crystal panel having a structure, a pixel barrier disposed on an upper portion of the liquid crystal panel and corresponding to the control pixel, and a backlight assembly positioned below the liquid crystal panel to supply light to the liquid crystal panel. .

A driving method of a liquid crystal display according to the present invention includes a) supplying light, b) selecting a wide viewing angle mode or a narrow viewing angle mode, and c) in the wide viewing angle mode, one pixel adjacent to each other red and green. Turning off the control pixel of the liquid crystal panel comprising a blue color pixel and a control pixel; d) diffusing light passing through the liquid crystal panel into a front and side viewing angle range; e) in the narrow viewing angle mode, A control pixel is turned on, and a viewing angle blocking signal is applied to the control pixel; f) a side viewing angle is blocked by a pixel barrier positioned above the control pixel to limit light diffusion to a narrow viewing angle range. Include.

Specific details of other embodiments are included in the detailed description and drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. Like reference numerals refer to like elements throughout.

Hereinafter, a liquid crystal display according to an exemplary embodiment and a driving method thereof will be described in detail with reference to the accompanying drawings.

3 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 4 is a plan view of FIG. 3 viewed from the front and the side.

Referring to FIG. 3, a liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal panel 110 for displaying an image, a pixel barrier 120 for controlling light blocking / transmission, and a backlight for generating light. Assembly 130.

The liquid crystal panel 110 includes a liquid crystal layer formed between the upper and lower substrates and the two substrates bonded at regular intervals.

On the liquid crystal panel 110, a plurality of color pixels R, G, and B and a control pixel C are arranged in a matrix form in a row and a column, and each pixel is illustrated in FIG. 4A. As shown in Fig. 2), the red, green, and blue color pixels R, G, and B and the control pixel C are adjacent to each other.

Although not shown, each color pixel (R, G, B) and the control pixel (C) of the liquid crystal panel 110 is provided with a thin film transistor that acts as a switching element, and whether or not on / off by pixel by the thin film transistor The magnitude of the drive voltage is controlled.

A color filter layer 111 for expressing color is formed in each pixel, and a black matrix 112 is formed between the pixels R, G, B, and C adjacent to each other to block light leakage.

The liquid crystal panel 110 orientates the liquid crystal layer formed between the upper and lower substrates by an electric field formed between the pixel electrode and the common electrode, and adjusts the amount of light passing through the liquid crystal layer according to the degree of alignment of the liquid crystal layer. Display an image.

When the TN (Twist nematic) structure is adopted for the liquid crystal panel 110, when the common electrode and the pixel electrode are formed on the upper and lower substrates, respectively, to form a vertical electric field, and the IPS (In Plane Switching) structure is employed The common electrode and the pixel electrode are formed together on the lower substrate to form a horizontal electric field. In particular, when the IPS structure is adopted, there is an advantage that the viewing angle can be wider in the wide viewing angle mode.

The pixel barrier 120 is positioned above the liquid crystal panel 110 and is formed to block an area corresponding to the control pixel C of each pixel.

The backlight assembly 130 is positioned at the rear of the liquid crystal panel 110 to supply light to the liquid crystal panel 110.

Referring to FIG. 4A, the liquid crystal panel 110 has a quad structure in which one pixel includes red, green, and blue color pixels R, G, and B, and a control pixel C. FIG.

Compared with the conventional quad structure in which one pixel is composed of red, green, blue, and white color pixels, the control pixel C is not used for the purpose of improving luminance, unlike the white color pixels. It is used together with the pixel barrier 120 disposed in front of (C) to use only side light.

Therefore, since the control pixel C is not seen from the front side as shown in FIG. 4B, and only the side surface is shown as shown in FIG.

When the control pixel C is turned off by applying a black signal to the control pixel C, since there is no light distorted in the lateral direction, a clear image can be seen over the entire wide viewing angle range (side and front viewing angles). When the control pixel C is turned on by applying the viewing angle blocking signal to the control pixel C, leakage light is generated, and the image ratio is distorted while the contrast ratio of each pixel is lowered.

In the narrow viewing angle mode, the following methods may be used to distort an image viewed in the lateral direction or to make it difficult to identify the screen from the side.

First, a white signal corresponding to the maximum luminance is applied to all the control pixels C of the liquid crystal panel 110 collectively.

Second, the viewing angle blocking signal applied to the control pixel C of the liquid crystal panel 110 is controlled so that a predetermined pattern or letters (eg, “a security screen”) is displayed as a whole in the lateral direction.

That is, in the narrow viewing angle mode, the viewing angle blocking signal of the control pixel C is controlled to display the front image and the side image.

Third, the liquid crystal panel 110 is divided into a predetermined number of unit regions, and the luminance of the control pixels C belonging to the divided unit regions and the color pixels R, G, and B positioned in the periphery thereof are compensated for each other. .

That is, the viewing angle blocking signal of the control pixel C is calculated using the luminance of the color pixels R, G, and B adjacent to the control pixel C in the unit area, and the calculated viewing angle blocking signal is converted into the control pixel ( C).

For example, the viewing angle blocking signal of the control pixel C is referred to as Iw and the maximum luminance is Imax, and the luminance of the red, green, and blue color pixels R, G, and B disposed adjacent to the control pixel C is determined. Let Ir, Ig, and Ib.

Here, Ir, Ig, and Ib may be the luminances of the red, green, and blue color pixels R, G, and B that are arranged in a quadrature structure with the control pixel C and constitute one pixel. The average luminance of each of the red, green, and blue color pixels R, G, and B arranged in the left, right, up, down, and diagonal directions based on the pixel C may be the same.

Then, in the narrow viewing angle mode, the value of Iw is controlled to satisfy the equation (1).

Iw = Imax-(Ir + Ig + Ib)

As such, the pixel barrier 120 is mounted on the control pixel C portion of the liquid crystal panel 110 having a quad structure except for the red, green, and blue color pixels R, G, and B, and the control pixel ( The viewing angle characteristic can be adjusted by controlling the signal applied to C).

When the control pixel C is turned off, the liquid crystal display exhibits wide-field characteristics. When the control pixel C is turned on to compensate for the luminance of the color pixels R, G, and B positioned nearby, the image is distorted from the side. As a result, the front image cannot be seen. For example, the control pixel C of each pixel displays the gray image on the side irrespective of the front image, thereby changing the viewing angle characteristic while maintaining the front resolution.

FIG. 5 is a model diagram illustrating the wide viewing angle mode and the narrow viewing angle mode of FIG. 3.

As the pixel barrier 120 is formed above the front of the control pixel C, and whether the control pixel C is turned on or turned off, the front and side surfaces thereof are controlled. The wide viewing angle mode in which both the viewing angles are valid and the narrow viewing angle mode in which the side viewing angles are blocked are selectively switched.

As such, when the structure of the pixel barrier 120 and the additional signal processing of the control pixel C are used, the viewing angle characteristic of the liquid crystal display may be efficiently changed.

In the wide viewing angle mode illustrated in FIG. 5A, a black signal corresponding to the lowest luminance is applied to the control pixel C to turn the control pixel C off.

When the control pixel C is turned off, the light passing through the control pixel C is blocked as shown in FIG. 5A, and there is no light distorting the image in the lateral direction. Therefore, the same image can be seen from both the front side and the side corresponding to the wide viewing angle range, so that the liquid crystal display has a wide viewing angle.

In the narrow viewing angle mode, a viewing angle blocking signal (for example, a white signal corresponding to maximum luminance) is applied to the control pixel C as shown in FIG. 5B. That is, the luminances of the red, green, and blue color pixels R, G, and B positioned nearby are compensated according to the luminance of the control pixel C. FIG.

In this case, since the control pixel C is covered by the pixel barrier 120 at the front, the original image and the resolution are maintained. In the side view, the image is distorted by the viewing angle blocking signal of the control pixel C, and a gray image is displayed on the screen of the liquid crystal display as a whole.

6 and 7 are graphs showing the viewing angle characteristics of FIG. 3.

8 is a graph illustrating a change in luminance according to a viewing angle in the narrow viewing angle mode of FIG. 3, and FIG. 9 is a graph illustrating a contrast ratio according to a viewing angle in FIG. 3.

The red, green, and blue color pixels (R, G, B) are configured to operate in an electrically controlled birefringence (ECB) mode in which the horizontally initially oriented liquid crystal material is controlled by a vertical electric field. In addition, the control pixel C is configured to operate in an in-plane switching (IPS) mode in which the liquid crystal material initially oriented horizontally is controlled by a horizontal electric field.

6 to 9 illustrate that the control pixels C and the red, green, and blue color pixels R, G, and B, which form the liquid crystal display of FIG. 3, are electrically controlled birefringence (ECB) mode and in-plane switching (IPS) mode. In the case of respectively configured to describe the viewing angle, brightness and contrast ratio characteristics.

FIG. 6 is a graph illustrating white and black luminance according to viewing angles of color pixels R, G, and B. FIG. (a1) is the transmittance according to the polar angle when the white signal is applied to the color pixels (R, G, B), (b1) is black with the color pixels (R, G, B) Transmittance according to the polar angle when the signal is applied is shown, respectively.

7 is a graph illustrating luminance according to the viewing angle of the control pixel C and whether voltage is applied. (a2) is the transmittance according to the polar angle when the control pixel C is turned on and the white signal is applied, and (b2) is the control pixel C when the control pixel C is turned off (or , Transmittance according to the polar angle when the voltage below the threshold voltage and the black signal are applied.

FIG. 8 is a graph illustrating luminance variation according to a viewing angle of the liquid crystal display shown in FIG. 3 in the narrow viewing angle mode.

When the control pixel C is controlled so that the luminance of the control pixel C compensates for the luminance of the adjacent color pixels R, G, and B, as shown in (a1) and (a2), the viewing angle is left and right. On the side of 40 degrees or more, the transmittances of the adjacent color pixels R, G, and B and the control pixel C become almost similar. Therefore, the pixel having the contrast ratio characteristics as shown in FIG. 9 can be designed.

FIG. 9 is a graph illustrating a contrast ratio according to a viewing angle of the liquid crystal display shown in FIG. 3.

Referring to FIG. 9, it can be seen that the left and right viewing angles are efficiently controlled so that a narrow viewing angle mode is implemented in which the contrast ratio is high at the front side where the viewing angle is about 0 °, and the contrast ratio is lowered at the side in which the viewing angle increases.

Accordingly, the red, green, and blue color pixels R, G, and B have an IPS structure having a viewing angle characteristic as shown in FIG. 6, and the control pixel C has a ECB structure having a viewing angle characteristic as shown in FIG. 7. It is desirable to have a contrast ratio characteristic of the form.

In the narrow viewing angle mode, the luminance (viewing angle blocking signal) of the control pixel C is generated using the luminance (image signal) of the color pixels R, G, and B positioned in the vicinity thereof, and the value is adjusted to adjust the viewing angle. By controlling the properties, the screen is not discernible from the side.

FIG. 10 is a model diagram for describing an efficient driving method of FIG. 3.

By controlling the type of color resin used for the control pixel C and the signal applied to the control pixel C, the image quality can be further improved in the wide viewing angle mode or the side images can be more completely displayed in the narrow viewing angle mode. It can be distorted.

Since the image of one frame is composed of a combination of red, green, and blue data, the original image may be maintained as it is, regardless of the pixel barrier 120 when the screen is viewed from the front direction as shown in (a).

However, when looking at the screen in the lateral direction as shown in (b), a part of the blue color pixel B may be covered by the pixel barrier 120, thereby degrading the original image.

In FIG. 2B, for convenience of description, it is assumed that the blue color pixels B are all shielded by the pixel barrier 120.

In this case, since the blue color pixel B is covered by the pixel barrier 120, in the narrow-view angle mode, the red and green color pixels R and G in which the viewing angle blocking signal of the control pixel C is arranged on the upper side. By compensating for the image signal, the side image is distorted.

On the other hand, if a yellow resin is applied to the control pixel C and the viewing angle blocking signal of the control pixel C is controlled to compensate for the luminance of the upper red and green color pixels R and G, the red, Since the luminance of the green color pixels R and G is the same as the luminance of the control pixel C, the narrow viewing angle mode may be more efficiently implemented.

On the other hand, when operating in the wide viewing angle mode, looking at the screen from the side direction, as shown in Fig. 10 (b) the blue color pixel (B) around the control pixel (C) is covered by the pixel barrier 120, the image quality is improved Deteriorates.

Therefore, deterioration of image quality can be prevented by treating the control pixel C with the same type of color resin as the color pixels disposed on the left and right sides of the control pixel C, and the blue resin in FIG. 10.

At this time, in the wide viewing angle mode, instead of turning off the control pixel C, an image signal of the blue color pixel B is applied to the control pixel C to improve image quality deterioration.

In addition, the red, green, and blue color pixels R, G, and B may be properly disposed so that the green color pixel G is positioned to the left and right of the control pixel C, and the control pixel C under the pixel barrier 120 is disposed. Also, the structure using green resin, which is brightest visually, is also effective for improving image quality.

FIG. 11 is a model diagram for embodying the structure of FIG. 3. FIG.

The pixel barrier 120 is formed to extend by a predetermined area from the outside of the control pixel C, including the front surface of the control pixel C. Herein, the size D + 2L of the pixel barrier 120 is a sum of the control pixel C, the overlap area D of the pixel barrier 120, and the length L of the outer region of the pixel barrier 120. . The length L of the outer region of the pixel barrier 120 is formed to cover all of the black matrices 112 arranged on both sides of the control pixel C.

The range of the narrow viewing angle is determined by the size D of the control pixel C and the spacing H between the control pixel C and the pixel barrier 120, and preferably, the control pixel C and the pixel barrier ( An interval H between 120 has a value corresponding to four to six times the size D of the control pixel C.

For example, when the size D of the control pixel C is 50 μm and the length L of the outer region of the pixel barrier 120 is 20 μm to 30 μm, the control pixel C and the pixel barrier ( The interval H between the layers 120 is 200 탆 to 300 탆.

When the size D + 2L of the pixel barrier 120 is equal to the size D of the control pixel C, the black matrix 112 arranged at both sides of the control pixel C may have different color pixels R, It is designed somewhat smaller than the case of G, B). At this time, when the size D of the control pixel C is small, the distance H between the control pixel C and the pixel barrier 120 should also be reduced.

The pixel barrier 120 is a passive barrier made of an opaque material such as chromium (Cr) or a resin material, and may be formed on the upper substrate of the liquid crystal panel 110 or on an independent substrate. have. When the pixel barrier 120 is formed on the upper substrate of the liquid crystal panel 110, the pixel barrier 120 is formed on a surface opposite to one surface on which the black matrix 112 and the color filter layer 111 are formed, and the control pixel C and the pixel barrier ( The spacing H between 120 becomes the thickness of the upper substrate.

After the pixel barrier 120 is attached to the liquid crystal panel 110, the light / narrow viewing angle mode is switched as a signal applied to each control pixel C of the liquid crystal panel 110 is controlled.

As such, when the pixel barrier 120 covering the control pixel C and the signal processing of the control pixel C are used, the viewing angle range may be controlled, and thus, a separate liquid crystal panel for controlling the viewing angle by varying the viewing angle characteristics. Without this, both wide viewing angle mode and narrow viewing angle mode can be implemented.

12 is a flowchart illustrating a method of driving a liquid crystal display according to an exemplary embodiment of the present invention, and illustrates a case in which the liquid crystal display of FIG. 3 is used.

First, in step S110, light is emitted from the backlight assembly 130 and supplied to the liquid crystal panel 110.

Next, in step S120, the liquid crystal panel 110 is switched to the wide viewing angle mode or the narrow viewing angle mode.

When the wide viewing angle mode is selected, step S130 is performed to turn off the control pixel C of the liquid crystal panel 110 and apply an image signal to the red, green, and blue color pixels R, G, and B. .

Thereafter, step S140 is performed, and the light supplied from the backlight assembly 130 is transmitted through the liquid crystal panel 110 and diffused into the front and side viewing angle ranges, and the original image without distortion is displayed on both the front and side surfaces.

Here, the pixel barrier 120 is positioned above the control pixel C, and since the control pixel C is turned off, the original front image and the resolution may be maintained.

When the narrow viewing angle mode is selected, step S150 is performed, so that the control pixel C of the liquid crystal panel 110 is turned on, and the viewing angle blocking signal is applied to the control pixel C.

Next, in step S160, the side viewing angle is blocked by the pixel barrier 120 positioned above the front of the control pixel C, so that light diffusion through the liquid crystal panel 110 is limited to the narrow viewing angle range.

In this case, since the viewing angle blocking signal is applied to the control pixel C, not the image signal, the side image different from the front image is seen from the side surface.

The viewing angle blocking signal applied to the control pixel C may be determined in various ways as described above in FIG. 4.

As the viewing angle blocking signal of the control pixel C is controlled, a side image different from the front image is displayed in the side direction. The viewing angle blocking signal of the control pixel C may be calculated using the luminance of the color pixels R, G, and B adjacent to the control pixel C.

For example, suppose that the viewing angle blocking signal of the control pixel C is Iw, the maximum luminance is Imax, and the luminance of the red, green, and blue color pixels disposed adjacent to the control pixel C is Ir, Ig, Ib. . Then, in the narrow viewing angle mode, the value of Iw operates to satisfy Equation 1, that is, Iw = Imax-(Ir + Ig + Ib).

Here, the range of the narrow viewing angle is determined by the size D of the control pixel C and the distance H between the control pixel C and the pixel barrier 120.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that.

Therefore, since the embodiments described above are provided to completely inform the scope of the invention to those skilled in the art, it should be understood that they are exemplary in all respects and not limited. The invention is only defined by the scope of the claims.

The liquid crystal display device and the driving method thereof according to the present invention made as described above can control the light blocking / transmission and viewing angle characteristics within a range in which a manufacturing process is easier and a cost is reduced as compared to a method using a dual liquid crystal panel. Can be.

In addition, the liquid crystal display and the driving method thereof according to the present invention apply a passive barrier to the liquid crystal panel and efficiently control a signal applied to the liquid crystal panel, thereby controlling the wide / narrow viewing angle mode without loss of resolution. Can be.

Claims (20)

A plurality of pixels arranged in a matrix form, each of the plurality of pixels having a quad structure consisting of adjacent red, green, and blue color pixels and a control pixel; A pixel barrier positioned above the liquid crystal panel and formed in an area corresponding to the control pixel; And A backlight assembly positioned under the liquid crystal panel to supply light to the liquid crystal panel Liquid crystal display comprising a. The method of claim 1, The red, green, and blue color pixels operate in an electrically controlled birefringence (ECB) mode in which the horizontally initially oriented liquid crystal material is controlled by a vertical electric field, And the control pixel operates in an In-Plane Switching (IPS) mode in which a horizontally initially aligned liquid crystal material is controlled by a horizontal electric field. The method of claim 1, The liquid crystal panel, A narrow viewing angle mode in which an image is displayed within a narrow viewing angle range, and a wide viewing angle mode in which an image is displayed within a wide viewing angle range are switched. The method of claim 3, The liquid crystal panel, And the control pixel is turned off in the wide viewing angle mode, and the control pixel is turned on in the narrow viewing angle mode. The method of claim 3, The liquid crystal panel, And controlling the viewing angle blocking signal of the control pixel in the narrow viewing angle mode to display a front image and a side image. The method of claim 3, The liquid crystal panel, And in the narrow viewing angle mode, the viewing angle blocking signal of the control pixel is calculated by using luminance of color pixels adjacent to the control pixel. The method of claim 6, The liquid crystal panel, When the viewing angle blocking signal of the control pixel is Iw and the maximum luminance is Imax, and the luminance of the red, green, and blue color pixels disposed adjacent to the control pixel is Ir, Ig, Ib, And controlling the value of Iw in the narrow viewing angle mode to satisfy equation Iw = Imax-(Ir + Ig + Ib). The method of claim 1, The control pixel, A liquid crystal display device, wherein white resin is used. The method of claim 1, Each of the plurality of pixels includes the red and green color pixels arranged side by side and a control pixel and a blue color pixel arranged side by side, And the control pixel is yellow resin. The method of claim 9, In the narrow viewing angle mode, And the luminance of the control pixel is controlled to compensate for the luminance of the red and green color pixels. The method of claim 1, Each of the plurality of pixels includes the red and green color pixels arranged side by side and a control pixel and a blue color pixel arranged side by side, The control pixel is a liquid crystal display, characterized in that blue resin is used. The method of claim 1, The control pixel, A liquid crystal display device, wherein green resin is used. The method of claim 3, The range of the narrow viewing angle is And a size (D) of the control pixel and a distance (H) between the control pixel and the pixel barrier. The method of claim 13, And as the size D of the control pixel decreases, the distance H between the control pixel and the pixel barrier also decreases. The method of claim 13, The distance H between the control pixel and the pixel barrier is And a value corresponding to four to six times the size (D) of the control pixel. a) supplying light; b) selecting a wide viewing angle mode or a narrow viewing angle mode; c) in the wide viewing angle mode, the control pixel of the liquid crystal panel of which one pixel is composed of red, green, and blue color pixels and a control pixel adjacent to each other is turned off; d) diffusing light passing through the liquid crystal panel to the front and side viewing angle ranges; e) in the narrow viewing angle mode, the control pixel is turned on and a viewing angle blocking signal is applied to the control pixel; And f) side viewing angle is blocked by a pixel barrier located above the control pixel to limit light diffusion to a narrow viewing angle range; Method of driving a liquid crystal display comprising a. The method of claim 16, Step e), And controlling the viewing angle blocking signal of the control pixel to display a front side image and a side image different from each other. The method of claim 16, Step e), And calculating the viewing angle blocking signal of the control pixel by using the luminance of the color pixels adjacent to the control pixel. The method of claim 18, Step e), When the viewing angle blocking signal of the control pixel is Iw and the maximum luminance is Imax, and the luminance of the red, green, and blue color pixels disposed adjacent to the control pixel is Ir, Ig, Ib, And controlling the value of Iw in the narrow viewing angle mode to satisfy Equation Iw = Imax− (Ir + Ig + Ib). The method of claim 16, The range of the narrow viewing angle of step f) is, And a size (D) of the control pixel and a distance (H) between the control pixel and the pixel barrier.

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