KR101267070B1 - Liquid crystal display for varying viewing angle, and driving method thereof - Google Patents

Abstract

A liquid crystal display and a driving method thereof that can vary the viewing angle are provided. The liquid crystal display includes: a liquid crystal panel having a first substrate and a second substrate facing each other and spaced apart from each other, and wherein the first liquid crystal is injected between the two substrates; A viewing angle input unit for inputting viewing angle data desired by a user; And a timing controller configured to output a variable voltage corresponding to the input viewing angle data. And a third substrate and a fourth substrate facing each other and spaced apart from each other, the second liquid crystal being injected between the two substrates, the second liquid crystal rearranged according to a variable voltage, and displayed on the liquid crystal panel. It includes a polarizing panel for varying the viewing angle of the output.

Liquid Crystal Display, Polarizing Panel, Variable Viewing Angle, Wide Viewing Angle, Narrow Viewing Angle

Description

Liquid crystal display with variable view angle and driving method thereof {LIQUID CRYSTAL DISPLAY FOR VARYING VIEWING ANGLE, AND DRIVING METHOD THEREOF}

1 is a perspective view of a general liquid crystal display.

2 is a diagram schematically illustrating a liquid crystal display device implementing a viewing angle using a compensation film according to the related art.

3 is a view schematically illustrating a liquid crystal display device implementing a wide viewing angle and a narrow viewing angle according to the related art.

4 is a configuration diagram of a liquid crystal display device capable of varying a viewing angle according to an exemplary embodiment of the present invention.

5 is a view for explaining a principle of implementing a variable viewing angle of a liquid crystal display according to an exemplary embodiment of the present invention.

6 is a diagram illustrating a connection structure of a liquid crystal display device having a variable viewing angle according to an exemplary embodiment of the present invention.

7 is a flowchart illustrating a method of driving a liquid crystal display device having a variable viewing angle according to an exemplary embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

100: first substrate (liquid crystal cell) 200: second substrate (liquid crystal cell)

300: first liquid crystal (liquid crystal cell) 410: third substrate (polarization panel)

420: Fourth substrate (polarization panel) 300: Second liquid crystal (polarization panel)

430: viewing angle input unit 440: timing controller

450: Look-up table 600, 700: Polarizing plate

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

In general, a liquid crystal display is an apparatus that expresses an image by using optical anisotropy and birefringence characteristics of liquid crystal molecules. In the liquid crystal display, two substrates on which the field generating electrodes are formed are disposed so that the surfaces on which the two electrodes are formed face each other, a liquid crystal material is injected between the two substrates, and then a voltage is applied to the two electrodes. By changing the arrangement of the liquid crystal molecules by the electric field, and by controlling the amount of light transmitted through the transparent insulating substrate, the desired image is expressed.

As the liquid crystal display, a thin film transistor liquid crystal display (TFT LCD) using a thin film transistor (TFT) as a switching element is mainly used. The TFT LCD transmits the red (R), green (G), and blue (B) color filter layers disposed 1: 1 on each liquid crystal pixel after the backlight having white light passes through the liquid crystal pixel and the light transmittance is adjusted. The color mixture of the TFT-LCD is produced by adding mixed color of the emitted light.

1 is a view schematically showing a configuration of a general liquid crystal panel.

Referring to FIG. 1, a liquid crystal panel provided in a liquid crystal display device includes a first substrate 10, a second substrate 20, and the first substrate 10 and the second substrate 20 bonded to each other with a predetermined space. And a liquid crystal layer 30 injected therebetween. In this case, the first substrate 10 is defined as a TFT region TFT, a pixel region Pixel, and a storage region C _ST which are switching regions.

The first substrate 10 includes a plurality of gate lines 12 in one direction at regular intervals on the transparent glass substrate 11, and a plurality of data lines at regular intervals in a direction perpendicular to the gate line 12. By arranging 16, the pixel region Pixel is defined.

In addition, a pixel electrode 18 is formed in each pixel region Pixel, and a thin film transistor TFT is formed at a portion where each of the gate lines 12 and the data lines 16 intersect, and the thin film transistors are formed in the gate. The data signal of the data line 16 is applied to each of the pixel electrodes 18 according to the scan signal applied through the line 12.

In the second substrate 20, a black matrix layer 22 is formed on the transparent glass substrate 21 to block light except for the pixel region Pixel. In the portion corresponding to each pixel region, a black matrix layer 22 is formed. R, G, and B color filter layers 23 are formed to express colors, and a common electrode 24 is formed on the color filter layers 23.

A charging capacitor C _ST connected in parallel with the pixel electrode 18 is configured on the gate line 12, and a portion of the gate line 12 is used as the first electrode of the charging capacitor C _ST . As the second electrode, an island-shaped metal pattern formed of the same material as the source and drain electrodes is used.

In the liquid crystal display, the liquid crystal layer 30 formed between the first substrate 10 and the second substrate 20 is aligned by an electric field between the pixel electrode 18 and the common electrode 24, and the liquid crystal is aligned. The desired image can be expressed by adjusting the amount of light passing through the liquid crystal layer 30 according to the degree of alignment of the layer 30.

Such a liquid crystal display is referred to as a twisted nematic (TN) mode liquid crystal display. Since the liquid crystal molecules constituting the liquid crystal cell have a thin and long bar shape and are twisted in a spiral with a constant pitch, It has a twisted structure in which the arrangement direction of the long axis of the liquid crystal molecules is continuously changed.

In such a TN mode liquid crystal display, the incident polarization shows different viewing angles depending on the arrangement of the long axis and the short axis of the molecule. That is, since the viewing angle of the liquid crystal display device is formed along the long axis of the liquid crystal molecules of the spiral structure, the viewing angle changes according to the viewing direction. The TN mode liquid crystal display has a symmetrical viewing angle ranging from approximately +45 to -45 with respect to the horizontal direction and a viewing angle limited between -15 and 5 degrees with respect to the vertical direction, so that the image is inverted at the vertical viewing angle. There is a problem that the viewing angle is narrowed.

On the other hand, when the liquid crystal display is small, a small number of users will often look at the liquid crystal display from a limited angle, but as the liquid crystal display becomes larger, many users may view the liquid crystal display from different angles. As the possibility increases, the limited viewing angle characteristic of the liquid crystal display becomes an important problem.

In order to overcome the limited viewing angle problem of the liquid crystal display, a film-compensated mode using a compensating film or a diffusing film and a pixel are divided into several domains. Multi-domain mode, which compensates the viewing angle by changing the direction of viewing angle of each domain, and IPS mode, which applies a transverse electric field by placing two electrodes driving liquid crystal on one plane. ) Has been proposed.

2 is a diagram schematically illustrating a liquid crystal display device implementing a viewing angle using a compensation film according to the related art.

Referring to FIG. 2, a liquid crystal display having a viewing angle using a compensation film may include a first substrate 10, a second substrate 20, a liquid crystal 30, a first compensation film 60, and a second compensation film. 70, the first polarizing plate 40 and the second polarizing plate 50, and the specific viewing angle is determined according to the type of the compensation film 70 attached to the second substrate 20, which is the upper plate, so that the user can freely There is a problem that the viewing angle cannot be selected.

3 is a view schematically illustrating a liquid crystal display device implementing a wide viewing angle and a narrow viewing angle according to the related art.

Referring to FIG. 3, in a liquid crystal display having a wide viewing angle and a narrow viewing angle, a polarizing panel in which a second liquid crystal 30 ′ is injected between a third substrate 80 and a fourth substrate 90 may be used. Is disposed on the substrate 20, the viewing angle is changed by rearranging the second liquid crystal 30 'by applying an electric field to the liquid crystal 30' between the third substrate 80 and the fourth substrate 90 All.

However, a liquid crystal display device implementing such a wide viewing angle and a narrow viewing angle may provide only two modes of a wide viewing angle or a narrow viewing angle. That is, since only the wide viewing angle or the narrow viewing angle can be selected by the on / off of the switch S, the user cannot freely select the viewing angle.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a liquid crystal display and a driving method thereof, by which a user may arbitrarily vary a range of viewing angles.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, a liquid crystal display having a variable viewing angle according to the present invention includes a first substrate and a second substrate facing each other and spaced apart from each other by a distance between the first substrate and the second substrate. A liquid crystal panel into which 1 liquid crystal is injected; A viewing angle input unit for inputting viewing angle data desired by a user; A timing controller configured to output a variable voltage corresponding to the viewing angle data input to the viewing angle input unit; And a third substrate and a fourth substrate facing each other and spaced apart from each other, wherein a second liquid crystal is injected between the third substrate and the fourth substrate, wherein the second liquid crystal is injected according to the variable voltage output from the timing controller. 2 a polarizing panel which rearranges the liquid crystals and varies and outputs a viewing angle of a screen displayed through the liquid crystal panel; A source printed circuit board for providing display data output from the timing controller to the liquid crystal panel and providing the variable voltage output from the timing controller to the polarizing panel; A connection printed circuit board for connecting the source printed circuit board and the polarizing panel; And an electrode pad provided on the polarization panel and fastened to the connection printed circuit board to supply the variable voltage to the first electrode and the second electrode of the polarization panel.

The display device may further include a lookup table that stores variable voltage data corresponding to the viewing angle input from the viewing angle input unit.

The polarizing panel may include first and second electrodes, and may receive the variable voltage from the timing controller through the first and second electrodes.

The first and second electrodes may be formed on a third substrate and a fourth substrate of the polarizing panel, or the first and second electrodes may be formed on any one of a third substrate and a fourth substrate of the polarizing panel. Can be formed.

Here, the second liquid crystal may be adjusted in the alignment angle in the range of 0 to 180 degrees corresponding to the variable voltage.

Here, the polarizing panel may rearrange the second liquid crystal corresponding to the variable voltage, and output the screen displayed from the liquid crystal panel at any one viewing angle adjusted in a range of 0 to 180 degrees.

In addition, a method of driving a liquid crystal display having a variable viewing angle according to the present invention may include: a) setting a variable voltage corresponding to a viewing angle data input by a user by searching and setting a look-up table; b) applying said variable voltage to a polarizing panel; c) rearranging liquid crystals of the polarizing panel according to the variable voltage; And d) outputting a screen displayed on the liquid crystal panel at a viewing angle varied according to the rearranged liquid crystals, and b) connecting a source printed circuit board, the source printed circuit board, and the polarizing panel. The variable voltage is supplied to the first electrode and the second electrode of the polarizing panel through a connection printed circuit board for connecting, and an electrode pad fastened to the connection printed circuit board.

Here, in the step a), the variable voltage corresponding to the input viewing angle may be searched from the lookup table to set the variable voltage.

The lookup table may be implemented in the timing controller or may be implemented in an external memory.

Specific details of other embodiments are included in the detailed description and the 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. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Hereinafter, a liquid crystal display and a driving method thereof capable of varying a viewing angle according to the present invention will be described in detail with reference to the accompanying drawings.

4 is a configuration diagram of a liquid crystal display device capable of varying a viewing angle according to an exemplary embodiment of the present invention.

Referring to FIG. 4, a liquid crystal display capable of varying a viewing angle according to an exemplary embodiment of the present invention may include a liquid crystal panel, a viewing angle input unit 430, a polarization panel, a timing controller 440, and a lookup table 450. have.

The liquid crystal panel includes a first substrate 100 and a second substrate 200 facing each other and spaced apart from each other, and the first liquid crystal 300 is injected between the two substrates.

The viewing angle input unit 430 is for inputting viewing angle data desired by a user, and may be input through an input means of a liquid crystal display, or may be input through an external system.

The timing controller 440 outputs a variable voltage Vcon corresponding to the input viewing angle data, and also outputs a gate signal, a data signal, a control signal, and the like to the liquid crystal panel.

The polarizing panel includes a third substrate 410 and a fourth substrate 420 facing each other and spaced apart from each other, and a second liquid crystal 300 ′ is injected between the two substrates, and according to the variable voltage. The second liquid crystal 300 ′ is rearranged and the screen displayed through the liquid crystal panel is output at a variable viewing angle. In this case, the second liquid crystal 300 ′ is adjusted in an alignment angle in a range of 0 to 180 degrees corresponding to the variable voltage.

The lookup table 450 stores variable voltage data corresponding to the viewing angle input from the viewing angle input unit 430 and is accessed by the timing controller 440.

Although not illustrated, a thin film transistor (TFT) and a pixel electrode may be formed on an inner surface of the first substrate 100, and a color filter may be formed on an inner surface of the second substrate 200. In this case, it is apparent to those skilled in the art that the common electrode is formed on the second substrate 200 in the TN mode and on the first substrate 100 in the IPS mode.

In addition, a first polarizing plate 600 is formed on an outer surface of the first substrate 100. Although not shown, a backlight is configured under the first polarizing plate 600 to supply light.

The polarizing panel is formed on the outer surface of the second substrate 200, and the second polarizing plate 700 is formed on the polarizing panel. The polarization panel includes third and fourth substrates 410 and 420 and a second liquid crystal 300 ′ interposed therebetween. In addition, first and second electrodes are formed on inner surfaces of the third and fourth substrates 410 and 420, respectively.

That is, the polarizing panel includes first and second electrodes, and receives the variable voltage Vcon from the timing controller 440 through the first and second electrodes. The first and second electrodes are formed on the third substrate 410 and the fourth substrate 420 of the polarizing panel, or the first and second electrodes are formed on the third substrate 410 of the polarizing panel or It may be formed on any one of the fourth substrate 420.

Specifically, the polarizing panel performs a function of controlling the viewing angle of the image data generated by the light applied from the backlight unit passing through the liquid crystal display panel through the alignment of the liquid crystal placed therein.

Meanwhile, the first and second substrates 100 and 200 may be made of glass, plastic, or resin. The first and second substrates 100 and 200 may be made of glass, plastic, or resin, and may be formed in the form of an adhesive film by forming an electrode and an alignment layer on one surface of a flexible film and coating an adhesive material on the other surface. It is desirable to. Similarly, the third and fourth substrates 410 and 420 may also be made of glass, plastic, or resin, and are formed in the form of an adhesive film by forming an electrode and an alignment layer on one side of the flexible film and coating an adhesive material on the other side. It is desirable to.

The second liquid crystal layer 300 ′ is capable of vertical, horizontal, hybrid, tilt, and twist orientations according to the optical characteristics of the first liquid crystal layer 300, and needs to adjust viewing angle characteristics and luminance characteristics. In some embodiments, the pixels may be aligned for each pixel.

5 is a diagram for describing a principle of implementing a variable viewing angle of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the third substrate 410 is a transparent substrate capable of transmitting light, and the first electrode 480 formed on the third substrate 410 may be made of a transparent conductive material such as ITO.

In addition, the fourth substrate 420 may also be a transparent substrate such as a glass substrate capable of transmitting light, and the second electrode 490 formed on the fourth substrate 420 may also be a transparent conductive material such as ITO.

Accordingly, when the voltage Vcon is applied to the first electrode 480 and the second electrode 490, the viewing angle of the polarizing panel is determined by aligning the liquid crystal 300 ′ interposed therebetween according to the distribution thereof. That is, the alignment angle of the liquid crystal 300 ′ may be adjusted in response to the voltage Vcon applied from the timing controller 440 to the polarization panel.

On the other hand, the polarizing panel applied to the embodiment of the present invention can be seen to operate almost the same as the liquid crystal display device without a color filter. In other words, since the first electrode 480 is formed in each predetermined region on the third substrate 410 having a plurality of signal lines formed in a matrix form, a voltage corresponding to a user's control is applied to the third substrate 410. It is understood that the plurality of signal lines operate substantially the same as the gate line and the data line of the liquid crystal display, and the first electrode 480 operates almost the same as the pixel electrode of the liquid crystal display, to which a voltage is applied according to the data signal. Can be.

Accordingly, the polarization panel according to the present invention can be implemented by various methods applicable to a conventional liquid crystal display, and a transverse electric field method in which a second electrode 490, which is a common electrode, is provided on the third substrate 410. It will be apparent to those skilled in the art that the present invention can be modified in various forms such as a polarization panel or a vertical alignment method (VA) polarization panel in which the initial liquid crystal alignment forms a vertical distribution.

6 is a diagram illustrating a connection structure of a liquid crystal display device having a variable viewing angle according to an exemplary embodiment of the present invention.

4 and 6, a liquid crystal display device having a variable viewing angle according to an exemplary embodiment of the present invention may include a source printed circuit board 460, a connection printed circuit board 470, an electrode pad 475, and the like. It may further include.

The source printed circuit board 460 provides display data to the liquid crystal panel and provides a variable voltage Vcon to the polarization panel.

The connection printed circuit board 470 is for interconnecting the source printed circuit board 460 and the polarizing panel. The connection printed circuit board 470 may be a flexible printed circuit board (FPC), but may also vary depending on the structure of the liquid crystal module.

An electrode pad 475 is provided on the polarizing panel to be fastened to the connection printed circuit board 470.

7 is a flowchart illustrating a method of driving a liquid crystal display device having a variable viewing angle according to an exemplary embodiment of the present invention.

Referring to FIG. 7, in the method of driving a liquid crystal display device having a variable viewing angle according to an exemplary embodiment of the present invention, first, a user arbitrarily inputs a desired viewing angle (S110). That is, a desired viewing angle is selected and input within a range of 0 degrees to 180 degrees using the input means of the external system or the input means provided in the liquid crystal display.

Next, in response to the viewing angle input by the user, the timing controller 440 illustrated in FIG. 4 sets the variable voltage Vcon (S120). At this time, the timing controller 440 searches for the variable voltage Vcon corresponding to the input viewing angle from the lookup table 450 to set the variable voltage Vcon, wherein the lookup table 450 sets the timing. It may be implemented in the controller 440 or may be implemented in an external memory.

Next, the timing controller 440 applies the variable voltage Vcon to the polarizing panel (S130). The polarizing panel includes a third substrate 410 and a fourth substrate 420 facing each other and spaced apart from each other by a predetermined distance, and a second liquid crystal 300 ′ is injected between the two substrates 410 and 420. have

Next, the polarization panel rearranges the liquid crystal corresponding to the variable voltage (S140). That is, the alignment angle of the liquid crystal 300 ′ is adjusted in a range of 0 to 180 degrees corresponding to the variable voltage.

 Therefore, the screen is displayed at a variable viewing angle corresponding to the rearranged liquid crystals (S150). That is, the polarizing panel rearranges the second liquid crystal 300 'according to the variable voltage Vcon, and accordingly outputs by adjusting the viewing angle of the screen displayed through the liquid crystal panel in the range of 0 to 180 degrees. can do.

As a result, the present invention attaches a liquid crystal cell that can act as a polarizing plate instead of a conventional polarizing film to the top plate, and can freely adjust the alignment angle of the liquid crystal according to a specific variable voltage. Can play a role. Accordingly, the present invention can freely adjust the range of the viewing angle according to the user's preference, the liquid crystal display device, etc. by adjusting the alignment angle of the liquid crystal in the polarizing panel.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

According to the present invention, the range of the viewing angle can be freely adjusted according to the user's preference or the use of the liquid crystal display.

Claims (17)

A liquid crystal panel having a first substrate and a second substrate facing each other and spaced apart from each other, wherein a first liquid crystal is injected between the first substrate and the second substrate; A viewing angle input unit for inputting viewing angle data desired by a user; And A timing controller configured to output a variable voltage corresponding to the viewing angle data input to the viewing angle input unit; And a third substrate and a fourth substrate facing each other and spaced apart from each other, wherein a second liquid crystal is injected between the third substrate and the fourth substrate, wherein the second liquid crystal is injected according to the variable voltage output from the timing controller. 2 a polarizing panel which rearranges the liquid crystals and varies and outputs a viewing angle of a screen displayed through the liquid crystal panel; A source printed circuit board for providing display data output from the timing controller to the liquid crystal panel and providing the variable voltage output from the timing controller to the polarizing panel; A connection printed circuit board for connecting the source printed circuit board and the polarizing panel; And And an electrode pad provided on the polarization panel and fastened to the connection printed circuit board to supply the variable voltage to the first electrode and the second electrode of the polarization panel. The method of claim 1, And a lookup table storing variable voltage data corresponding to the viewing angle input from the viewing angle input unit. delete The method of claim 1, And the first and second electrodes are formed on a third substrate and a fourth substrate of the polarizing panel. The method of claim 1, And the first and second electrodes are formed on any one of a third substrate and a fourth substrate of the polarizing panel. The method of claim 1, The second liquid crystal of claim 2, wherein the alignment angle is adjusted in the range of 0 to 180 degrees corresponding to the variable voltage. The method of claim 1, The polarizing panel rearranges the second liquid crystal corresponding to the variable voltage, and outputs a screen displayed from the liquid crystal panel at any one viewing angle adjusted in a range of 0 to 180 degrees. delete The method of claim 1, And the connection printed circuit board is a flexible printed circuit board (FPC). The method of claim 1, A first polarizer arranged under the liquid crystal panel; And A second polarizing plate arranged on the polarizing panel Liquid crystal display further comprising. a) searching and setting a look-up table for a variable voltage corresponding to the viewing angle data input by the user; b) applying said variable voltage to a polarizing panel; c) rearranging liquid crystals of the polarizing panel according to the variable voltage; And d) outputting a screen displayed on the liquid crystal panel at a viewing angle varied according to the rearranged liquid crystals, Step b) is the polarization panel through the variable voltage through a source printed circuit board, a connection printed circuit board for connecting the source printed circuit board and the polarizing panel, and an electrode pad fastened to the connection printed circuit board. And a first electrode and a second electrode of the liquid crystal display. delete 12. The method of claim 11, And the lookup table is implemented in a timing controller. 12. The method of claim 11, And the lookup table is implemented as an external memory. 12. The method of claim 11, The polarizing panel includes a third substrate and a fourth substrate facing each other and spaced apart from each other, and a second liquid crystal is injected between the third substrate and the fourth substrate, and the second liquid crystal is changed according to the variable voltage. Rearranging and outputting a screen displayed on the liquid crystal panel at a variable viewing angle. 12. The method of claim 11, The liquid crystal of step c) is characterized in that the alignment angle is adjusted in the range of 0 to 180 degrees corresponding to the variable voltage. 12. The method of claim 11, And d) outputting the screen displayed from the liquid crystal panel at any one viewing angle adjusted in a range of 0 to 180 degrees.

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