Liquid crystal display device

• US 20030146893A1
• Filed: 01/02/2003
• Published: 08/07/2003
• Est. Priority Date: 01/30/2002
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Sawabe, Daiichi
• Granted Patent: US 7,113,159 B2
• Time in Patent Office: Days
• US Class Current: 345/89
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• CPC Class Codes: G09G 2300/0447 for multi-domain technique to improve the viewing angle in a liquid crystal display, such as multi-vertical alignment [MVA]
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/028 by changing the viewing angle properties, e.g. widening the viewing angle, adapting the viewing angle to the view direction
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2320/068 for control of viewing angle adjustment
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A liquid crystal display device including a liquid crystal panel being capable of gradation display is provided with a LUT and a drive signal generation section for adjusting gradation curve'"'"'s distortion with respect to a viewing angle, which indicates a relation between a gradation and a luminance ratio on a display screen of the liquid crystal panel. With this arrangement, it is possible to freely switch on the display screen of the liquid crystal panel between a wide viewing angle display and a narrow viewing angle display. Therefore, it is possible to provide a liquid crystal display device which adjusts the gradation curve'"'"'s distortion with respect to the viewing angle on the display screen to obtain a high contrast and an excellent gradation curve in a wide range of viewing angle, thereby improving a display quality level of a display screen; and which realizes a display screen with a narrow viewing angle, thereby allowing information not desired to be seen by other people to be securely displayed thereon.

Claims

1. A liquid crystal display device having a liquid crystal panel being capable of gradation display, which includes distortion adjusting means for adjusting gradation curve'"'"'s distortion with respect to a viewing angle, the gradation curve indicating a relation between a gradation and a luminance ratio on a display screen of the liquid crystal panel.

2. The liquid crystal display device according to claim 1, wherein the distortion adjusting means include (a) a look-up table referred to for adjustment of the gradation curve'"'"'s distortion with respect to the viewing angle and (b) display data generating means for generating display data in which the gradation curve'"'"'s distortion with respect to the viewing angle is adjusted in accordance with a reference result of the look-up table.

3. The liquid crystal display device according to claim 2, wherein (b) the display data generating means, when generating data on sub-pixels, generate a plurality of patterns in accordance with the display data and change the patterns frame by frame.

4. The liquid crystal display device according to claim 3, wherein (b) the display data generating means generate a pattern on sub-pixels to decrease a degree of correlation between a pattern which is changed frame by frame and a pattern for switching of a voltage applying direction.

5. The liquid crystal display device according to claim 4, wherein a polarity of voltage applied to a liquid crystal is inverted frame by frame so that the voltage applying direction is switched.

6. The liquid crystal display device according to claim 1, wherein the distortion adjusting means include (a) a plurality of look-up tables referred to for adjustment of the gradation curve'"'"'s distortion with respect to the viewing angle, (b) selecting means for selecting the look-up tables, and (c) display data generating means for generating display data in which the gradation curve'"'"'s distortion with respect to the viewing angle is adjusted in accordance with a reference result of the look-up tables.

7. The liquid crystal display device according to claim 6, wherein (c) the display data generating means, when generating data on sub-pixels, generate a plurality of patterns in accordance with the display data and change the patterns frame by frame.

8. The liquid crystal display device according to claim 7, wherein (c) the display data generating means generate a pattern on sub-pixels to decrease a degree of correlation between a pattern which is changed frame by frame and a pattern for switching of a voltage applying direction.

9. The liquid crystal display device according to claim 1, wherein one pixel in the liquid crystal panel is composed of a plurality of sub-pixels each being capable of independent drive, and

the distortion adjusting means set display data supplied to the liquid crystal panel so as to show respectively different gradation curves with respect to all of the sub-pixels in the one pixel.

10. The liquid crystal display device according to claim 1, wherein one pixel in the liquid crystal panel is composed of sub-pixels corresponding to three primary colors, and at least one sub-pixel of a color other than the three primary colors, and

the distortion adjusting means set display data supplied to the liquid crystal panel so as to show respectively different gradation curves with respect to all of the sub-pixels in the one pixel.

11. The liquid crystal display device according to claim 10, wherein the sub-pixel other than the sub-pixels corresponding to the three primary colors is a sub-pixel of white.

12. The liquid crystal display device according to claim 1, wherein one frame for displaying one pixel in the liquid crystal panel is composed of a plurality of sub-frames, and

the distortion adjusting means set display data supplied to the liquid crystal panel so as to show respectively different gradation curves with respect to all of the sub-frames for displaying the one pixel.

13. The liquid crystal display device according to claim 1, wherein the liquid crystal panel is driven with a mode of a liquid crystal with a wide viewing angle for increasing a viewing angle.

14. The liquid crystal display device according to claim 1, wherein the distortion adjusting means divide an inputted frame into sub-frames each having a half cycle of the inputted frame and output the sub-frames.

15. The liquid crystal display device according to claim 14, wherein the sub-frame is outputted continuously.

16. The liquid crystal display device according to claim 15, wherein change by continuous output of the sub-flames occurs at the frequencies from 30 Hz to 80 Hz.

17. The liquid crystal display device according to claim 1, wherein the distortion adjusting means include a logical circuit which carries out frame-by-frame switching of the sub-pixels.