DRIVING DEVICE FOR LIQUID CRYSTAL DISPLAY PANEL AND LIQUID CRYSTAL DISPLAY DEVICE

Abstract

A liquid crystal display panel driving device is provided which is capable of reliably improving a response speed of a liquid crystal and of obtaining good display quality. When overshooting driving is performed in a current frame for displaying, an excessive response level in a next frame is predicted based on a combination of a gray level in one past frame and a gray level in a current frame and, when an excessive response is predicted, a corrected gray-level value to prevent (or to cancel) the excessive response is calculated in advance. By applying a voltage corresponding to the corrected gray-level value, an excessive response in a next frame can be suppressed. Irrespective of whether or not an excessive response is predictable in a next frame, an overshooting driving can be performed at an applied voltage sufficiently corresponding to a target gray-level value and, as a result, a response speed of a liquid crystal can be reliably made high and good display quality can be obtained.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, advantages, and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a block diagram showing electrical configurations of a liquid crystal display device according to a first embodiment of the present invention;

FIG. 2 is a block diagram showing electrical configurations of an LCD (Liquid Crystal Display) driving circuit making up the liquid crystal display device according to the first embodiment of the present invention;

FIG. 3 is a perspective view schematically showing configurations of a liquid crystal display panel making up the liquid crystal display device according to the first embodiment of the present invention;

FIG. 4 is a cross-sectional view schematically showing configurations of the liquid crystal display panel of FIG. 3;

FIG. 5 is a diagram of an equivalent circuit showing electrical configurations of the liquid crystal display panel of FIG. 3;

FIG. 6 is a block diagram showing configurations of a control section and a storing section of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 7 is a diagram showing contents of a first LUT stored in the first LUT storing section making up the storing section of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 8 is a diagram showing contents of a second LUT stored in the second LUT storing section making up the storing section of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 9 is a diagram showing contents of a third LUT stored in the third LUT storing section making up the storing section of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 10 is a diagram showing a format of a frame data stored in the frame memory making up the storing section of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 11 is a diagram explaining operations of the LCD driving circuit of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 12 is also a diagram explaining operations of the LCD driving circuit of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 13 is a diagram showing a format of frame data stored in the frame memory making up the storing section of the liquid crystal display device according to the first embodiment of the present invention;

FIG. 14 is a diagram explaining a conventional technology;

FIG. 15 is a diagram explaining the conventional technology;

FIG. 16 is a diagram explaining the conventional technology; and

FIG. 17 is a diagram explaining the conventional technology.

Claims

1. A driving device for a liquid crystal display panel wherein said liquid crystal display panel comprises a plurality of data electrodes arranged along a first direction, a plurality of scanning electrodes arranged along a second direction being approximately orthogonal to said first direction, and a liquid crystal layer, wherein said driving device applies scanning signals to said plurality of scanning electrodes and display signals providing gray levels to the plurality of corresponding data electrodes to write pixel data providing gray levels on corresponding pixels of said liquid crystal layer in said liquid crystal display panel, and wherein, by said driving device, overshoot gray-level data (or, undershoot gray-level data) is generated based on input display data for each pixel and, for a pixel on which an overshooting operation is performed this time (or, on which an undershooting operation is performed this time), gray-level data or overshoot gray-level data (or, undershoot gray-level data) is set to be somewhat lower by a specified amount (in the case of undershooting driving, the data is set to be somewhat higher by a specified amount) and is applied to each of the data electrodes.

2. The driving device for the liquid crystal display device according to claim 1, further comprising: a gray-level data outputting circuit to generate and output said gray-level data or said overshoot gray-level data (or, undershoot gray-level data); anda data electrode driving circuit to perform an overshooting driving (or, undershooting driving) by applying said displaying signals to said data electrodes so that, when said data electrode driving circuit receives said overshoot gray-level data (or, undershoot gray-level data), a gray-level voltage to be applied to said pixel corresponds to said overshoot gray-level data (or, undershoot gray-level data) and becomes an overvoltage being larger than a reference voltage (in the case of undershooting driving, becomes an undervoltage being smaller than said reference voltage, wherein said gray-level data outputting circuit comprises:an overshoot gray-level value calculating unit (or, undershoot gray-level value calculating unit) to calculate an overshoot gray-level value (or, undershoot gray-level value) in a current frame based on a current gray-level value in said current frame in which an overshooting driving is performed and a previous gray-level value;a correcting unit to predict an excessive response that may occur in a next-time frame displaying based on said current gray-level value and said previous gray-level value and to obtain a level of an excessive response or a corrected amount of the next-time gray-level to prevent an excessive response; anda corrected gray-level value calculating unit to calculate a corrected gray-level value or overshoot gray-level value (or undershoot gray-level value) based on a level of said excessive response or said corrected amount of said next-time gray-level value.

3. The driving device for the liquid crystal display device according to claim 2, wherein said correcting unit comprises an excessive response level estimating unit to predict an excessive response at time of displaying in said next-time frame based on said current gray-level value and said previous gray-level value at time of displaying for overshooting driving (or, for undershooting driving) in said current frame and estimates a level of said excessive response.

4. The driving device for the liquid crystal display device according to claim 1, still further comprising an image information storing unit to store at least one frame of image information.

5. The driving device for the liquid crystal display device according to claim 4, wherein said image information storing unit stores information obtained by adding a level of said excessive response in said next frame or said corrected amount to image information in said current frame.

6. The driving device for the liquid crystal display device according to claim 5, wherein said excessive response level estimating unit sends out information obtained by adding a level of said excessive response in said next-time frame to image information in said current frame to said image information storing unit and said corrected gray-level value calculating unit receives a level of said excessive response from said image information storing unit at time of displaying in a frame and calculates said corrected amount based on a level of said excessive response and obtains a corrected gray-level value or overshoot gray-level value (or, undershoot gray-level value) based on the corrected amount.

7. The driving device for the liquid crystal display device according to claim 1, still further comprising an overshoot gray-level value storing unit (or, undershoot gray-level value storing unit) to store said overshoot gray-level value (or, undershoot gray-level value) corresponding to said current gray-level value and said previous gray-level value and a corrected amount storing unit corresponding to said current gray-level value and said previous gray-level value.

8. The driving device for the liquid crystal display device according to claim 7, still further comprising an excessive response level storing unit to store a level of said excessive response corresponding to said current gray-level value and said previous gray-level value.

9. The driving device for the liquid crystal display device according to claim 8, wherein said overshoot gray-level value storing unit (or, undershoot gray-level value storing unit) stores said overshoot gray-level value (or undershoot gray-level value) actually measured in advance and said corrected amount storing unit stores said corrected amount actually measured in advance and said excessive response level storing unit stores said excessive response level actually measured in advance.

10. The driving device for the liquid crystal display device according to claim 1, further comprising: a gray-level data outputting circuit to generate and output said gray-level data or said overshoot gray-level data (or, undershoot gray-level data); anda data electrode driving circuit to perform an overshooting driving (or, undershooting driving) by applying said displaying signals to said data electrodes so that, when said data electrode driving circuit receives said overshoot gray-level data (or, undershoot gray-level data), a gray-level voltage to be applied to said pixel corresponds to said overshoot gray-level data (or, undershoot gray-level data) and becomes an overvoltage being larger than a reference voltage (in the case of undershooting driving, becomes an undervoltage being smaller than said reference voltage, wherein said gray-level data outputting circuit comprises:an overshoot gray-level value calculating means (or, undershoot gray-level value calculating means) to calculate an overshoot gray-level value (or, undershoot gray-level value) in a current frame based on a current gray-level value in said current frame in which an overshooting driving is performed and a previous gray-level value;a correcting means to predict an excessive response that may occur in a next-time frame displaying based on said current gray-level value and said previous gray-level value and to obtain a level of an excessive response or a corrected amount of the next-time gray-level to prevent an excessive response; anda corrected gray-level value calculating means to calculate a corrected gray-level value or overshoot gray-level value (or undershoot gray-level value) based on a level of said excessive response or said corrected amount of said next-time gray-level value.

11. The driving device for the liquid crystal display device according to claim 10, wherein said correcting means comprises an excessive response level estimating means to predict an excessive response at time of displaying in said next-time frame based on said current gray-level value and said previous gray-level value at time of displaying for overshooting driving (or, for undershooting driving) in said current frame and estimates a level of said excessive response.

12. The driving device for the liquid crystal display device according to claim 1, still further comprising an image information storing means to store at least one frame of image information.

13. The driving device for the liquid crystal display device according to claim 12, wherein said image information storing means stores information obtained by adding a level of said excessive response in said next frame or said corrected amount to image information in said current frame.

14. The driving device for the liquid crystal display device according to claim 13, wherein said excessive response level estimating means sends out information obtained by adding a level of said excessive response in said next-time frame to image information in said current frame to said image information storing means and said corrected gray-level value calculating means receives a level of said excessive response from said image information storing means at time of displaying in a frame and calculates said corrected amount based on a level of said excessive response and obtains a corrected gray-level value or overshoot gray-level value (or, undershoot gray-level value) based on the corrected amount.

15. The driving device for the liquid crystal display device according to claim 1, still further comprising an overshoot gray-level value storing means (or, undershoot gray-level value storing means) to store said overshoot gray-level value (or, undershoot gray-level value) corresponding to said current gray-level value and said previous gray-level value and a corrected amount storing means corresponding to said current gray-level value and said previous gray-level value,

16. The driving device for the liquid crystal display device according to claim 15, still further comprising an excessive response level storing means to store a level of said excessive response corresponding to said current gray-level value and said previous gray-level value.

17. The driving device for the liquid crystal display device according to claim 16, wherein said overshoot gray-level value storing means (or, undershoot gray-level value storing means) stores said overshoot gray-level value (or undershoot gray-level value) actually measured in advance and said corrected amount storing means stores said corrected amount actually measured in advance and said excessive response level storing means stores said excessive response level actually measured in advance.

18. A liquid crystal display device comprising: a liquid crystal display panel which comprises a plurality of data electrodes arranged along a first direction, a plurality of scanning electrodes arranged along a second direction being approximately orthogonal to said first direction, and a liquid crystal layer; anda driving device for a liquid crystal display panel which applies scanning signals to said plurality or scanning electrodes and applies display signals providing gray levels to the plurality of corresponding data electrodes to write pixel data providing gray levels on corresponding pixels of said liquid crystal layer; wherein said driving device applies scanning signals to said plurality of scanning electrodes and display signals providing gray levels to the plurality of corresponding data electrodes to write pixel data providing gray levels on corresponding pixels of said liquid crystal layer in said liquid crystal display panel, and wherein, by said driving device, overshoot gray-level data (or, undershoot gray-level data) is generated based on input display data for each pixel and, for a pixel on which an overshooting operation is performed this time (or, on which an undershooting operation is performed this time), gray-level data or overshoot gray-level data (or, undershoot gray-level data) is set to be somewhat lower by a specified amount (in the case of undershooting driving, the data is set to be somewhat higher by a specified amount) and is applied to each of the data electrodes.

19. The liquid crystal display device according to claim 18, wherein said driving device further comprises: a gray-level data outputting circuit to generate and output said gray-level data or said overshoot gray-level data (or, undershoot gray-level data); anda data electrode driving circuit to perform an overshooting driving (or, undershooting driving) by applying said displaying signals to said data electrodes so that, when said data electrode driving circuit receives said overshoot gray-level data (or, undershoot gray-level data), a gray-level voltage to be applied to said pixel corresponds to said overshoot gray-level data (or, undershoot gray-level data) and becomes an overvoltage being larger than a reference voltage (in the case of undershooting driving, becomes an undervoltage being smaller than said reference voltage, wherein said gray-level data outputting circuit comprises:an overshoot gray-level value calculating unit (or, undershoot gray-level value calculating unit) to calculate an overshoot gray-level value (or, undershoot gray-level value) in a current frame based on a current gray-level value in said current frame in which an overshooting driving is performed and a previous gray-level value;a correcting unit to predict an excessive response that may occur in a next-time frame displaying based on said current gray-level value and said previous gray-level value and to obtain a level of an excessive response or a corrected amount of the next-time gray-level to prevent an excessive response; anda corrected gray-level value calculating unit to calculate a corrected gray-level value or overshoot gray-level value (or undershoot gray-level value) based on a level of said excessive response or said corrected amount of said next-time gray-level value.