KR101386280B1 - Liquid Crystal Display Device Capable of Controlling Viewing Angle and Driving Method thereof - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a liquid crystal display capable of controlling the viewing angle which enables confidentiality and security regardless of the type of image.

A liquid crystal display device capable of controlling a viewing angle includes: a liquid crystal panel provided with color sub pixels of a first method and interference sub pixels of a second method; An input unit for inputting color sub data for the color sub pixels; A signal adaptive interference data generator for generating mixed interference subpixel data in which video interference subpixel data based on the color subpixel data from the input unit and fixed interference subpixel data of a predetermined fixed pattern are mixed; And a panel driver for driving the color sub pixels and the interfering sub pixels in response to the color sub data from the input unit and the mixed interference sub pixel data from the signal adaptive interference data generator.

Gamma voltage, selection, interference, vertical electric field, horizontal electric field, lateral direction, luminance.

Description

Liquid Crystal Display Device Capable of Controlling Viewing Angle and Driving Method

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the drawings used in the detailed description of the present invention, a brief description of each drawing is provided.

1 is a cross-sectional view schematically showing a conventional liquid crystal panel capable of controlling a viewing angle.

2 is a block diagram schematically illustrating a liquid crystal display capable of controlling a viewing angle according to an exemplary embodiment of the present invention.

3 is a cross-sectional view illustrating a structure of an interference sub pixel and a color sub pixel on the liquid crystal panel of FIG. 2.

4A to 4C are diagrams illustrating polarization characteristics of the liquid crystal panel shown in FIG. 3.

5A and 5B are views showing the state of an image on the liquid crystal panel seen from the side in the case of the wide viewing angle mode and the narrow viewing angle mode by the liquid crystal display of FIG.

FIG. 6 is a detailed block diagram illustrating in detail the luminance adaptive interference pattern generator of FIG. 2.

7 is a characteristic diagram illustrating an operation of a video interference data generator.

8 is a diagram for describing gray level mapping between video interference sub pixel data and color sub pixel data.

DESCRIPTION OF THE REFERENCE NUMERALS to the main parts of the drawings "

30: liquid crystal panel 40: luminance adaptive interference pattern generator

42: video data combination unit 44: gate driver

46: data driver 48: timing controller

70: combiner 71: side luminance detector

72: adder 73: difference detector

74: video interference data generator 75: interference pattern memory

76: memory controller 77,79: first and second selectors

78: offset data register

The present invention relates to a liquid crystal display device capable of controlling the viewing angle of an image and a driving method thereof.

The liquid crystal display device displays an image by controlling an intensity of an electric field applied to the liquid crystal to adjust an amount of light passing through the liquid crystal. Such a liquid crystal display device can make the size of the screen larger than the limit while reducing the thickness. Further, the liquid crystal display device can be made slimmer and lighter. In view of this, the liquid crystal display device is used as a display device of a computer or a display device of a television receiver instead of a cathode ray tube (Cathode Ray Tube) display device.

In recent years, users of information terminals such as mobile phones, personal digital assistants (hereinafter referred to as "PDAs"), computers, and the like require users to prevent others from reading information. In response to requests for confidentiality and security of such information terminals, liquid crystal displays used as display devices of information terminals are also required to accommodate not only a normal viewing angle mode but also a narrow viewing angle mode.

In order to satisfy the demands of the viewing angle control, a liquid crystal panel having a dual viewing angle mode in which a separate interfering sub-pixel is added to color pixels has been proposed. As one form of the liquid crystal panel of a viewing angle control mode, the liquid crystal panel of a dual structure is mentioned. This dual structure liquid crystal panel includes, as shown in Fig. 1, a normal panel 10 in which color pixels are formed; And an interference panel 12 positioned on the top panel 10 and having interference sub-pixels. The top panel 10 is used to display an image while the interfering panel 12 allows light to travel toward the side of the panel to be blocked. The liquid crystal panel of the dual structure enables switching of the viewing angle mode with respect to the image by blocking side light by the interference panel 12. The viewing angle controllable liquid crystal display including the dual structure liquid crystal panel selectively drives the interference panel 12 to implement a wide viewing angle mode and a narrow viewing angle mode. In other words, the liquid crystal display causes the interference panel 12 to be turned on or turned off depending on the viewing angle mode. In such a dual structure liquid crystal panel, since the external light must pass through the double liquid crystal layer, the brightness of the image is significantly lowered. In addition, the liquid crystal panel of the dual structure causes thickness and weight to increase.

As another form of the liquid crystal panel of the viewing angle control mode, a liquid crystal panel of an area division method in which color pixels and interfering sub pixels are arranged in the same plane has also been proposed. In the region division type liquid crystal panel, each of the color pixels includes red, green, and blue subpixels and an interfering subpixel. Since the interference sub-pixels are arranged in the same plane as the color sub-pixels, the liquid crystal panel of the region division method does not increase in thickness and weight. In addition, the area division type liquid crystal panel can control the viewing angle by only one liquid crystal layer, so that not only the amount of light but also the luminance and color purity can be prevented.

A liquid crystal display device (hereinafter referred to as "liquid crystal display device in dual viewing angle mode") including the dual viewing angle liquid crystal panel is a liquid crystal panel in double viewing angle mode in order to selectively display an image of a normal viewing angle and an image of a narrow viewing angle. The interference sub-pixels of the image are selectively driven. In other words, only color sub-pixels except for interfering sub-pixels are driven when displaying an image of a normal viewing angle, while color sub-pixels as well as interfering sub-pixels are driven when displaying an image with a narrow viewing angle.

In such a method of displaying an image having a narrow viewing angle by driving the interfering sub-pixels together with the color sub-pixels, a method and a constant pattern of increasing the luminance through the interfering sub-pixels adaptively in accordance with the lateral luminance to be displayed by the color sub-pixels. In accordance with this, a method of increasing luminance through an interfering sub-pixel is used. In the method of increasing the luminance according to the luminance of the color sub-pixels, an image having a small change in luminance can be made invisible from the side as shown in the figure, while a side of an image having a large change in outline such as text containing characters is shown. It was difficult to make it invisible. On the other hand, the method of increasing the luminance through the interfering sub-pixels according to a certain pattern, while it is possible to make the image with a large change in outline, such as text including characters, from the side, but the image with a small change in luminance as shown in the figure It was difficult to make far from the side. In addition, in the method of increasing the luminance through the interfering sub-pixels according to a certain pattern, even the image at the front side cannot be identified due to excessive light transmission at the side. For this reason, in the conventional liquid crystal display device of the viewing angle control mode, it is difficult to maintain confidentiality and security depending on the type of image. In addition, the liquid crystal display of the conventional viewing angle control mode may display an unidentifiable image from the front due to excessive increase in side luminance.

Accordingly, an object of the present invention is to provide a viewing angle controllable liquid crystal display device and a driving method thereof which enable confidentiality and security regardless of the type of image.

Another object of the present invention is to provide a liquid crystal display device and a method of driving the same, which can be identified from the front and can ensure confidentiality and security.

According to an aspect of the present invention, there is provided a liquid crystal display device capable of controlling a viewing angle, the liquid crystal panel including color sub-pixels of a first type and interference sub-pixels of a second type; An input unit for inputting color sub data for the color sub pixels; A signal adaptive interference data generator for generating mixed interference subpixel data in which video interference subpixel data based on the color subpixel data from the input unit and fixed interference subpixel data of a predetermined fixed pattern are mixed; And a panel driver for driving the color sub pixels and the interfering sub pixels in response to the color sub data from the input unit and the mixed interference sub pixel data from the signal adaptive interference data generator.

A video interference data generator, wherein the signal adaptive interference data generator generates the video interference subpixel data using the color subpixel data from the input unit; A memory storing pattern interference sub-pixel data forming the fixed pattern; And a selector for selectively supplying the video interference sub pixel data from the interference data generator and the fixed interference sub pixel data from the memory to the panel driver.

A side component detector for detecting the lateral component of color sub-pixel data from the input by the video interference data generator; And a gray scale value adjuster generating the video interference sub-pixel data by adjusting the detected lateral component by a difference from a reference value.

The lateral direction component may include lateral luminance of the color sub pixel data.

According to another aspect of the present invention, there is provided a driving method of a liquid crystal display capable of controlling a viewing angle, the method including inputting color sub data to be written in color sub pixels on a liquid crystal panel; Generating the interfering subpixel data to be used for driving the interfering subpixels on the liquid crystal panel in a form including video interfering subpixel data based on the color subpixel data and fixed interfering subpixel data of a predetermined fixed pattern. ; And driving the color sub pixels and the interfering sub pixels in response to the color sub data and the interfering sub pixel data.

Other objects, other advantages and other features of the present invention will become apparent from the detailed description of the preferred embodiments with reference to the accompanying drawings, in addition to the objects of the present invention as described above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram schematically illustrating a liquid crystal display capable of controlling a viewing angle according to an exemplary embodiment of the present invention. Referring to FIG. 2, the liquid crystal display capable of controlling the viewing angle may include the luminance adaptive interference pattern generator which generates interference data to be supplied to the interfering sub-pixels ESP11 to ESPmn on the liquid crystal panel 30. 40); And a video data combination unit 42 for adding the interference data IDF from the luminance adaptive interference pattern generator 40 to the video data VD from an external video source.

In the liquid crystal panel 30, the subpixels RSP11 ˜ in each of the regions divided by the plurality of data lines DL1 through DL2m arranged in the horizontal direction and the plurality of gate lines GL1 through GL2n arranged in the vertical direction. RSPmn, GSP11 ~ GSPmn, BSP11 ~ BSPmn, ESP11 ~ ESPmn) are prepared. Each of these sub-pixels RSP11 to RSPmn, GSP11 to GSPmn, BSP11 to BSPmn, and ESP11 to ESPmn each includes a data line in response to a scan signal on the liquid crystal cell CLC and the gate line GL connected to the common electrode Vcom. The thin film transistor MN for switching the sub pixel driving signal to be transmitted from the DL to the liquid crystal cell CLC is provided. Among the sub pixels, the red sub pixels RSP11 to RSPmn are connected to the odd gate lines GL1 to GL2n-1 and the odd data lines DL1 to DL2m-1, respectively, and the green sub pixels GSP11 to GSPmn are connected to each other. ) Are connected to the odd-numbered gate lines GL1 to GL2n-1 and even-numbered data lines DL2 to DL2m, respectively, and the blue sub-pixels BSP11 to BSPmn are respectively the even-numbered gate lines GL2 to GL2n and even. The interfering sub-pixels ESP11 to ESPmn are connected to the even-numbered gate lines GL2 to GL2n and the odd-numbered data lines DL1 to DL2m-1, respectively. In addition, the interference sub-pixels ESP11 to ESPmn each have a pair of adjacent red, green, and blue sub-pixels RSP11 to RSPmn, GSP11 to GSPmn, and BSP11 to BSPmn to control the viewing angle. The pixels PXC11 to PXCmn are constituted. Accordingly, the first and second color pixels PXC11 of the first line are commonly connected to the first gate line GL1 and red and green subpixels connected to the first and second data lines DL1 and DL2, respectively. It includes common and connected to the RSP11 and GSP11 and the second gate line GL2, and the interference and blue subpixels ESP11 and BSP11 connected to the first and second data lines DL1 and DL2, respectively. In this manner, the last color pixel PXCmn of the last line is also commonly connected to the 2n-1th gate line GL2n-1 and connected to the 2m-1 and 2mth data lines DL2m-1 and DL2m, respectively. Interference and blue subpixels commonly connected to the red and green subpixels RSPmn and GSPmn and to the 2nth gate line GL2n and connected to the 2m-1 and 2mth data lines DL2m-1 and DL2m, respectively. (ESPmn, BSPmn). Each of the red, green, and blue sub-pixels RSP11 to RSPmn, GSP11 to GSPmn, and BSP11 to BSPmn is driven in a horizontal electric field to display an image so that it can be viewed from a wide angle. On the other hand, each of the interfering sub-pixels ESP11 to ESPmn is driven in a vertical electric field manner, so that the image to be viewed from the side except the front side is selectively interfered with the interfering sub-pixel signal. When the image to be seen from the side is interfered by these interfering sub-pixels ESP11 to ESPmn, the image displayed on the liquid crystal panel 30 may be viewed only in a narrow angle range based on the definition of the liquid crystal panel 30. do. In other words, when there is interference by the interfering sub-pixels ESP11 to ESPmn, the liquid crystal panel 30 causes the image of the narrow viewing angle mode to be displayed. In contrast, when there is no interference by the interfering sub-pixels ESP11 to ESPmn, the image of the wide viewing angle mode is displayed on the liquid crystal panel 30.

The color sub-pixels RSP, GSP, and BSP and the interfering sub-pixels ESP on the liquid crystal panel 30 have a structure as shown in FIG. 3. Referring to FIG. 3, the liquid crystal panel 30 includes a liquid crystal layer CL positioned between the lower glass substrate 31 and the upper organic substrate 36. The gate insulating layer 32, the data line DL, and the protective layer 33 are sequentially formed on the lower glass substrate 31. A thin film transistor and a gate line (not shown) are formed between the gate insulating film 32 and the lower glass substrate 31. The data line DL is electrically connected to the thin film transistor via the gate insulating layer 32. Based on the data line DL, the left half corresponds to the color sub subpixel RSP, GSP or BSP, and the right part of the data line DL corresponds to the interfering subpixel ESP. The first pixel electrodes 34A and the common electrodes 35A are alternately formed on the surface of the passivation layer 33 positioned on the left half of the data line DL. On the other hand, the second pixel electrode 34B is formed on the surface of the protective layer 33 of the right half of the data line DL. The first pixel electrodes 34A and the first common electrodes 35A are formed in the shape of a band, while the second pixel electrode 34B is formed in the shape of a flat plate having a size of an area of the sub-pixel.

A black matrix 37 is formed on the bottom surface of the upper glass substrate 36 to divide the sub pixel region. A color sub filter (red, green or blue sub filter (RSP, GSP or BSP)) 38 is formed in each of the color sub pixel areas among the pixel areas divided by the black matrix 37. The overcoat layer 39 is formed on the surfaces of the black mattress 37 and the color filter 38. The second common electrode 35B having the size of the sub pixel region is formed in the right half of the overcoat layer 39 (that is, the right region of the data line DL).

In this way, the color sub-pixels RSP, GSP, or BSP are connected to the liquid crystal layer CL by the first pixel electrodes 34A and the first common electrodes 35A that are alternately arranged on the lower glass substrate 31. The electric field in the horizontal direction is applied. Then, the liquid crystal molecules CLCM included in the color sub-pixels RSP, GSP, or BSP responding to the voltage applied between the first pixel electrodes 34A and the first common electrodes 35A are illustrated in FIG. 4A. As shown in FIG. 6, the transmitted light is polarized so that the amount of light decreases as the viewing angle increases toward the lateral side with respect to the front side. Accordingly, the image displayed on the liquid crystal panel 30 is also viewed from the side of a wide angle with respect to the front of the liquid crystal panel 30. In other words, the liquid crystal panel 30 causes the image of the wide viewing angle mode to be displayed. On the other hand, the interfering sub-pixel ESP is perpendicular to the liquid crystal layer CL by the second pixel electrode 34B and the second common electrode 35B disposed on the lower and upper glass substrates 31 and 36, respectively, facing each other. Allow an electric field in the direction to be applied. The liquid crystal molecules CLCE in the interfering sub-pixel ESP in response to the magnitude of the vertical electric field applied between the second pixel electrode 34B and the second common electrode 35B are shown in FIG. 4B. On the basis of the front surfaces of the liquid crystal panels 30 and 30A, the light is polarized so as to maximize the amount of light on the side of about 40 ° on both sides. In other words, the liquid crystal molecules CLCE included in the interfering sub-pixel ESP polarize the light to move toward both sides except the front side. The light traveling toward the side by the interference sub-pixel ESP is combined with the light traveling toward both sides via the color sub-pixels RSP, GSP, and BSP, and the liquid crystal panel 30 as shown in FIG. 4C. In the front of the liquid crystal panel 30, the amount of light traveling toward the side at a 40 ° angle is maximized, whereas the front of the liquid crystal panel 30 has a polarization intensity characteristic of decreasing the amount of light. The amount of light from the interfering sub-pixel ESP that is transmitted at an angle of about 40 ° on both sides with respect to the front of the liquid crystal panel 30 is added to the amount of light from the color sub-filters RSP, GSP, and BSP. An image of information different from the original information is displayed on the liquid crystal panel 30 to be seen at an angle near 40 ° on both sides of (30).

As described above, the liquid crystal panel 30 including the interfering sub-pixels ESP in addition to the color sub-pixels RSP, GSP, and BSP enables control of the viewing angle. In addition, in the liquid crystal panel 30, the interfering sub-pixel ESP is disposed on the same plane along with the color sub-pixels RSP, GSP, and BSP so that the thickness and the weight thereof do not increase. In addition, the liquid crystal panel 30 together with the color sub-pixels RSP, GSP, and BSP allows the interfering sub-pixel ESP to be provided on the same plane so that the viewing angle can be controlled by only one liquid crystal layer and the amount of light is reduced. Of course, the degradation of the luminance can be prevented.

Referring back to FIG. 2, the luminance adaptive interference pattern generator 40 responds to the optical / narrow mode control signal W / N from an external video source (for example, a graphics card of a computer). The luminance adaptive interference pattern data IDF is supplied to the video data combiner 42 to cause the viewing angle of 30 to be broadly or narrowly switched. This luminance adaptive interference pattern data IDF is obtained by the liquid crystal panel 30 when the optical / narrow mode control signal W / N has a specific logic (for example, high logic or low logic) that specifies the narrow viewing angle mode. Interfering light is added to both sides with respect to the front side. In addition, the luminance adaptive interference pattern data IFD may vary according to the interference sub-pixel data Ep and the video data VD of the fixed pattern, which form an image of the fixed interference pattern (for example, text including characters). Interfering sub-pixel data Ed of video adaptation is included. In order to generate interfering sub-pixel data Ed of video adaptation that varies from picture to picture, the interference data generating unit 40 inputs video data VD from an external video source (for example, a graphics card of a computer). . On the other hand, when the light / narrow mode control signal W / N has initialization logic (for example, low logic or high logic) for designating the wide viewing angle mode, the interference data IDF is generated from the liquid crystal panel 30. Off-set sub-pixel data Eoff having an offset value that prevents the interfering light from traveling toward both sides with respect to the front side.

The video data combination unit 42 inputs video data VD including color sub pixel data for red, green, and blue sub pixels RSP, GSP, and BSP from an external video source (not shown). . The video data combiner 42 adds the luminance adaptive interference data IDF from the luminance adaptive interference pattern generator 40 to the video data VD. In addition, the video data combination unit 42 rearranges the color sub-pixel data and the interfering sub-pixel data (Ed and Ep or Eoff) to match the arrangement state of the sub-pixels on the liquid crystal panel 30 to combine the combined video data (CVD). ) Is generated. The combined video data CVD provided by the video data combination unit 42 includes red and green sub-pixels RSP and GSP connected to the odd-numbered gate lines GL1 to GL2n-1 of the liquid crystal panel 30. ) Is scanned when the red and green sub-pixel data Rd and Gd are alternately included, while the interference and blue connected to the even-numbered gate lines GL2 to GL2n of the liquid crystal panel 30 are included. When the sub-pixels ESP and BSP are scanned, the sub-pixel data stream includes alternating interference and blue sub-pixel data (((Ed and Ep) or Eoff) and Bd).

In addition, the liquid crystal display according to the exemplary embodiment may include a gate driver 44 for sequentially driving the gate lines GL1 to GL2n on the liquid crystal panel 30, and data lines on the liquid crystal panel 30. Data driver 46 for driving DL1 to DL2m, and timing controller 48 for controlling the operation timing of these data and gate drivers 44,46. The gate driver 44 generates 2n scan signals sequentially enabling the gate lines GL1 to GL2n in response to the gate timing signal GTS from the timing controller 48. By 2n scan signals, the gate lines GL1 to GL2n on the liquid crystal panel 30 are sequentially and exclusively enabled for each period corresponding to half of the period of the horizontal synchronization signal.

The data driver 46, in response to the data timing signal DTS from the timing controller 48, each time one of the gate lines GL1 to GL2n is enabled, the 2m data lines DL1 to DL2m. ) To supply the sub pixel driving signals. For this purpose, the data driver 46 inputs the combined video data CVD transmitted in the serial form from the video data combining unit 42. When the columns of the red and green sub-pixels RSP and GSP connected to any one of the odd-numbered gate lines GL1 to GL2n-1 are scanned, the data driver 46 stores the red and green sub-pixel data Rd,. By inputting the sub data stream in which Gd) is alternated, the red sub pixel driving signals are respectively provided to the odd-numbered data lines DL1 to DL2m-1, and the green sub pixel driving signal is provided to each of the even-numbered data lines DL2 to DL2m. To be supplied. On the other hand, when the interference and blue sub-pixels ESP and BSP connected to any one of the even-numbered gate lines GL2 to GL2n are scanned, the data driver 46 may detect the interference and the blue sub-pixel data ((Ed). And Ep), Eoff), and Bd) are inputted to alternate subpixel data streams, and each of the odd-numbered data lines DL1 to DL2m-1 has an interference subpixel driving signal and even-numbered data lines DL2 to DL2m. The blue sub pixel driving signal is supplied to each of them.

The interfering sub-pixel driving signal has a specific logic for specifying the narrow viewing angle when the light / narrow mode control signal W / N specifies the narrow viewing angle, so that the interfering sub-pixel ESP is opposite to the front side of the liquid crystal panel 30. It has a voltage that allows the interfering light to be transmitted. The amount of light transmitted to both sides by the interfering sub-pixel ESP is adjusted according to the voltage level of the interfering sub-pixel driving signal. The amount of light transmitted to both sides by the interfering sub-pixels ESP is added to the amount of light transmitted to both sides by the red, green, and blue sub-pixels RSP, GSP, and BSP so that the luminance component from the side interferes. To be. As a result, as shown in FIG. 5B, an image that cannot be seen from the side is displayed on the liquid crystal panel 30. In addition, the interfering sub-pixel driving signals have different voltage levels according to the positions of the interfering sub-pixels ESP11 to ESPmn corresponding to the composite image in which the fixed interference pattern and the video image are mixed. Causes a difference in the amount of interference. Accordingly, not only the text image displayed on the liquid crystal panel 30 but also the image of the picture cannot be identified at both sides. As a result, secrecy and security in narrow viewing angle mode are further enhanced.

On the contrary, when the light / narrow mode control signal W / N has initialization logic for specifying the wide viewing angle, the interfering sub-pixel ESP transmits the interfering light to both sides thereof including the front of the liquid crystal panel 30. In response to the offset sub-pixel drive signal of the offset voltage. Due to the offset sub-pixel driving signal of the offset voltage, there is no light passing through the interfering sub-pixel ESP. Only the light transmitted to the front and both sides thereof. Accordingly, the image displayed on the liquid crystal panel 30 is clearly seen not only from the front but also from the side as in FIG. 5A.

Finally, timing controller 48 inputs synchronization signals (ie, horizontal and vertical synchronization signals and data clocks) from an external video source. The timing controller 48 generates the gate timing signal GTS to be supplied to the gate driver 44 and the data timing signal DTS to be supplied to the data driver 46 using the synchronization signals. In addition, the timing controller 48 includes an interference control signal ECS required for the interference data generation operation of the luminance adaptive interference pattern generator 40 and a combination control signal CCS required for the data combination operation of the video data combiner 42. Occurs.

FIG. 6 is a detailed block diagram illustrating an embodiment of the luminance adaptive interference pattern generator 40 in FIG. 2. The luminance adaptive interference pattern generator 40 of FIG. 6 includes a side luminance detector 71, an adder 72, a difference detector 73, and a video interference data generator 74 connected in series with the combiner 70. . The combiner 70 sequentially inputs red, green, and blue sub-pixel data Rd, Gd, and Bd inputted in a serial form from an external video source, thereby receiving the red, green, and blue sub-pixel data Rd. , Gd and Bd are simultaneously delivered to the side luminance detector 71. For this purpose, the combiner 70 responds to the first interference control signal ECS1 from the timing controller 48 in FIG. As the first interference control signal ECS1, a data clock having the same period as that of the sub pixel data is preferably used. In the combiner 70, a shift for sequentially shifting the red, green, and blue sub-pixel data Rd, Gd, and Bd from an external video source in response to the first interference control signal ECS1 such as a data clock. Registers can be used.

The side luminance detector 71 calculates side luminance data for each of the red, green, and blue sub-pixel data Rd, Gd, and Bd input in parallel. To this end, the side luminance detector 71 pre-calculates the side luminance data (hereinafter, referred to as the gray scale values) of the red, green, and blue sub-pixel data Rd, Gd, and Bd, respectively. A "look-up table" ("red, green and blue sub-pixel side luminance data") is arranged. This look-up table causes the red, green and blue sub-pixel side luminance data on the storage area corresponding to the respective logic values of the red, green and blue sub-pixel data Rd, Gd and Bd to be output. By the lock-up table, the propagation delay period in the side luminance detector 71 is significantly reduced.

The red, green and blue sub-pixel side luminance data calculated by the side luminance detector 71 are summed by the adder 72 so that the color pixel side luminance data is calculated. The color pixel side luminance data Yt calculated by the adder 72 is supplied to the difference detector 73 and the video interference data generator 74.

The difference detector 73 calculates a difference value between the color pixel side luminance data Yt and the reference luminance value by subtracting the color pixel side luminance data Yt from the adder 72 with the reference luminance value. The reference luminance value is measured by adjusting until the image becomes invisible from the side through the display experiment of the narrow viewing angle image. The video interference data generator 74 compensates the gray level value (or logic value) of the color pixel side data Yt up or down by the detected difference value from the difference detector 73 to generate the video interference sub pixel data. For example, as shown in FIG. 7, when the color pixel side luminance data Yt1 is higher than the reference luminance value, the video interference data generator 74 attenuates the gray level value of the color pixel side luminance data Yt1 by the difference value. Or downward) to generate video interference sub-pixel data Ed. On the contrary, as shown in FIG. 7, if the color pixel side luminance data Yt2 is lower than the reference luminance value, the video interference data generator 74 amplifies the gray level value of the color pixel side luminance data Yt1 by the difference value (or Upward) to generate video interference sub-pixel data Ed. In this way, the difference detector 73 and the video interference data generator 74 for calculating the video interference sub-pixel data Ed from the color pixel side luminance data Yt are logical values (ie, gray scale values) of the color pixel side luminance data. Correspondingly, the video interference sub-pixel data Ed0, which is calculated in advance by calculation using a reference luminance value, may be replaced with a look-up table having an array.

Alternatively, the video interfering sub-pixel data Ed may be calculated by a look-up table that uses logical values (ie, grayscale values) of red, green and blue sub-pixel data as one address. In this case, the video interference sub pixel data Ed has a side view control effect according to the sum of the red, green and blue sub pixel data or the luminance value of the color pixel obtained through the matrix processing of the red, green and blue sub pixel data. It is prepared in advance by mapping between the first grayscale curve 90 and the second grayscale curve 92 in FIG. 8 obtained through the experiment. In Fig. 8, the first gradation curve 90 shows a change in luminance value or the sum of the gradations due to the red, green, and blue sub pixel data, and the second gradation curve 92 shows the video interference sub pixel data Ed. ) Shows the change in gradation.

In addition, the luminance adaptive interference pattern generator 40 includes a first selector 77 connected to both the video interference data generator 74 and the interference pattern memory 75. The interference pattern memory 75 stores pattern interference sub-pixel data Ep that includes only characters or forms an interference pattern including the characters and the background of a specific grayscale. The pattern interfering sub-pixel data Ep are sequentially read and supplied to the first selector 77 under the control of the memory controller 76. The first selector 77 selectively selects the pattern interference sub pixel data Ep from the interference pattern memory 75 and the video interference sub pixel data Ed from the video interference data generator 74. To feed. The first selector 77 selects the video interference sub pixel data Ed or the pattern interference sub pixel data Ep depending on whether the pattern interference sub pixel data Ep has a specific gray value. Accordingly, the first selector 77 outputs the luminance adaptive interference subpixel data stream Ed + Ep in which the video interference subpixel data Ed and the pattern interference subpixel data Ep are mixed and arranged.

The second selector 79 is the offset sub-pixel data Eoff from the offset data register 78 or the first according to the logic value of the optical / narrow mode control signal W / N from an external video source. The luminance adaptive interfering sub-pixel data stream Ed + Ep from the selector 77 is transmitted as the interference data IDF to the video data combination section 42 of FIG. If the wide / narrow mode control signal W / N has a specific logic (i.e., high logic or low logic) to specify the narrow viewing angle mode, the second selector 79 will cause luminance adaptive interference from the first selector 77; The sub pixel data Ed + Ep is supplied to the video data combination section 42 of FIG. 2 as the interference data IDF. Conversely, if the wide / narrow mode control signal W / N has initialization logic (i.e., low logic or high logic) that specifies the wide viewing angle, then the second selector 79 may select an offset from the offset data register 78. The set sub pixel data EFF is supplied to the video data combiner 42 of FIG. 2 as the interference data IDF.

As described above, in the liquid crystal display device capable of controlling the viewing angle and the driving method thereof according to the present invention, The interfering sub-pixel driving signals to be supplied to the interfering sub-pixels on the liquid crystal panel have different voltage levels according to the positions of the interfering sub-pixels by the composite image in which the fixed interference pattern and the video image are mixed. Thus, the interference sub-pixel driving signal whose level varies depending on the position of the interference sub-pixel causes a difference in the amount of interference of luminance for each color pixel. Accordingly, the text image displayed on the liquid crystal panel as well as the image of the picture cannot be identified at all on both sides. As a result, secrecy and security in the narrow viewing angle mode are further enhanced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be apparent that various modifications, alterations, and other equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the technical idea and scope of the present invention to be protected must be determined by the appended claims.

Claims (8)

A liquid crystal panel in which horizontal subfield color subpixels arranged in the left half with respect to the data lines and vertical subfield interfering subpixels arranged in the right half with respect to the data lines; An input unit for inputting color sub data for the color sub pixels; A signal adaptive interference data generator for generating mixed interference subpixel data in which video interference subpixel data based on the color subpixel data from the input unit and fixed interference subpixel data of a predetermined fixed pattern are mixed; And And a panel driver configured to drive the color subpixels and the interfering subpixels in response to the color subdata from the input unit and the mixed interference subpixel data from the signal adaptive interference data generator. Controllable liquid crystal display. The method of claim 1, wherein the signal adaptive interference data generator, A video interference data generator for generating the video interference subpixel data using the color subpixel data from the input unit; A memory storing pattern interference sub-pixel data forming the fixed pattern; And And a selector for selectively supplying the video interference sub pixel data from the interference data generator and the fixed interference sub pixel data from the memory to the panel driver. The method of claim 2, wherein the video interference data generator, A side component detector for detecting lateral luminance of color sub-pixel data from the input unit; And And a gradation value controller for generating the video interference sub-pixel data by adjusting the detected lateral luminance by a difference from a reference value. delete delete Inputting color sub data to be written in horizontal subfield color subpixels disposed at a left half with reference to a data line on the liquid crystal panel; The interfering sub pixel data to be used for driving the interfering sub pixels of the vertical electric field method disposed in the right half with respect to the data line on the liquid crystal panel is divided into the video interfering sub pixel data based on the color sub pixel data and a preset fixed pattern. Generating a fixed interference sub-pixel data; And And driving the color sub-pixels and the interfering sub-pixels in response to the color sub-data and the interfering sub-pixel data. The method of claim 6, wherein the step of generating interference data, Generating the video interference sub-pixel data using the color sub-pixel data; Reading the fixed interfering sub pixel data from a memory; And selecting the video coherent sub pixel data and the fixed coherent sub pixel data from the memory. The method of claim 7, wherein the generating of the video interference sub-pixel data, Detecting lateral luminance of the color sub pixel data; And And calculating the video interference sub-pixel data by adjusting the detected lateral luminance by a difference from a reference value.

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