LIQUID CRYSTAL DRIVING DEVICE

Abstract

A liquid crystal driving device is provided which enables an overshooting driving operation in transition among all gray levels. When a voltage for displaying is controlled so as to be a highest-level value out of the voltages for displaying corresponding to an input gray level range, an overshooting driving voltage for transition to a higher voltage which is added to a voltage side being higher than the highest-value value out of the voltages for displaying is applied to a liquid crystal panel and, when a voltage for displaying to be applied to the liquid crystal panel is controlled so as to be a lowest-level value out of the voltages for displaying corresponding to the input gray level range, an overshooting driving voltage for transition to a lower voltage which is added to a voltage side being lower than the lowest-level value of the voltages for displaying is applied to the liquid crystal panel.

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 diagram showing a method for driving a liquid crystal panel used in a liquid crystal driving device according to a first embodiment of the present invention;

FIGS. 2A and 2B are diagrams showing a relation between a panel applied voltage and display gray level according to the first embodiment of the present invention;

FIG. 3 is a diagram showing, as an example, a state of changes in voltages applied to a liquid crystal panel during a transition of gray level when voltages for displaying are different from one another in the method of driving the liquid crystal panel according to the embodiment of the present invention;

FIG. 4 is a diagram explaining a relation between a gray-level value setting voltage and a source driver output voltage according to the embodiment of the present invention;

FIG. 5 is a diagram showing a method for driving a liquid crystal panel according to a second embodiment of the present invention;

FIG. 6 is a diagram showing a method for driving a liquid crystal panel according to a third embodiment of the present invention;

FIG. 7 is a diagram showing a method for driving a liquid crystal panel according to a fourth embodiment of the present invention;

FIG. 8 is a diagram showing a method for driving a liquid crystal panel according to a fifth embodiment of the present invention;

FIG. 9 is a diagram showing an example of configurations of a liquid crystal display device of a conventional technology;

FIG. 10 is a table showing an example of data in an LUT;

FIG. 11 is a diagram for showing another example of configurations of a liquid crystal display device of the conventional technology;

FIG. 12 is a diagram showing a first example of an overshooting driving method applied to a conventional liquid crystal display device;

FIG. 13 is a diagram explaining a state of changes in voltages applied to a liquid crystal panel at time of transition of gray levels when voltages for displaying vary in the conventional liquid crystal driving method shown in FIG. 12; and

FIG. 14 is a diagram showing a second example of an overshooting driving method applied to the conventional liquid crystal display device.

Claims

1. A liquid crystal driving device comprising: a liquid crystal panel whose transmittance changes depending on an applied voltage; and a driver to apply a voltage for displaying set according to a gray level of an input signal to said liquid crystal panel with timing determined by an input signal;wherein, said driver applies an overshooting driving voltage for transition to a higher voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a highest-level voltage out of voltages for displaying corresponding to a range of input gray levels, which is added to a voltage side being higher than said highest-level voltage out of said voltages for displaying, to said liquid crystal panel; andwherein, said driver applies an overshooting driving voltage for transition to a lower voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be said lowest-level voltage out of voltages for displaying corresponding to a range of input gray levels, which is added to a voltage side being lower than said lowest-level voltage out of said voltages for displaying, to said liquid crystal panel.

2. The liquid crystal driving device according to claim 1, wherein the overshooting voltages for transition to a higher voltage and for transition to a lower voltage are set independently from said voltages for displaying.

3. A liquid crystal driving device comprising: a liquid crystal panel whose transmittance changes depending on an applied voltage; anda driver to apply a voltage for displaying set according to a gray level of an input signal to said liquid crystal panel with timing determined by an input signal;wherein said driver applies an overshooting driving voltage for transition to a higher (or lower) voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a highest-level (or lowest-level) voltage out of voltages for displaying corresponding to a range of input gray levels, which is added to a voltage side being higher (or lower) than said highest-level (or lowest-level) voltage out of said voltages for displaying to said liquid crystal panel,wherein said driver controls said voltages for displaying being higher (or lower) by voltages corresponding to m (m is a natural number) gray levels from the lowest-level (or highest-level) voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a lowest-level (or highest-level) voltage out of said voltages for displaying corresponding to a range of input gray levels; andwherein said driver uses voltages between a voltage being higher (or lower) by voltages corresponding to m gray levels from said lowest-level (or highest-level) voltage and said lowest-level (or highest-level) voltage as an overshooting driving voltage for a transition to a lower (or higher) voltage.

4. A liquid crystal driving device comprising: a liquid crystal panel whose transmittance changes depending on an applied voltage; anda driver to apply a voltage for displaying set according to a gray level of an input signal to said liquid crystal panel with timing determined by an input signal;wherein said driver applies an overshooting driving voltage for transition to a higher (or lower) voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a highest-level (or lowest-level) voltage out of voltages for displaying corresponding to a range of input gray levels, which is added to a voltage side being higher (or lower) than said highest-level (or lowest-level) voltage out of said voltages for displaying, to said liquid crystal panel;wherein, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a lowest-level (or highest-level) voltage out of said voltages for displaying corresponding to a range of input gray levels, no overshooting driving operation is performed.

5. The liquid crystal driving device according to claim 3, wherein the overshooting voltage for transition to a higher (or lower) voltage is set independently from said voltages for displaying.

6. The liquid crystal driving device according to claim 4, wherein the overshooting voltage for transition to a higher (or lower) voltage is set independently from said voltages for displaying.

7. The liquid crystal driving device according to claim 1, further comprising an FRC, wherein said voltages for displaying for halftones corresponding to the number of voltages for input gray levels being in short supply caused by setting of the overshooting driving voltages for transition to a higher voltage and for transition to a lower voltage are generated, by using said FRC, from said voltages for displaying corresponding to higher and lower gray levels of halftones being in short supply.

8. The liquid crystal driving device according to claim 2, further comprising an FRC, wherein said voltages for displaying for halftones corresponding to the number of voltages for input gray levels being in short supply caused by setting of the overshooting driving voltages for transition to a higher voltage and for transition to a lower voltage are generated, by using said FRC, from said voltages for displaying corresponding to higher and lower gray levels of halftones being in short supply.

9. The liquid crystal driving device according to claim 3, further comprising an FRC, wherein said voltages for displaying for halftones corresponding to the number of voltages for input gray levels being in short supply caused by setting of the overshooting driving voltages for transition to a higher voltage and for transition to a lower voltage are generated, by using said FRC, from said voltages for displaying corresponding to higher and lower gray levels of halftones being in short supply.

10. The liquid crystal driving device according to claim 4, further comprising an FRC, wherein said voltages for displaying for halftones corresponding to the number of voltages for input gray levels being in short supply caused by setting of the overshooting driving voltages for transition to a higher voltage and for transition to a lower voltage are generated, by using said FRC, from said voltages for displaying corresponding to higher and lower gray levels of halftones being in short supply.

11. The liquid crystal driving device according to claim 5, further comprising an FRC, wherein said voltages for displaying for halftones corresponding to the number of voltages for input gray levels being in short supply caused by setting of the overshooting driving voltages for transition to a higher voltage and for transition to a lower voltage are generated, by using said FRC, from said voltages for displaying corresponding to higher and lower gray levels of halftones being in short supply.

12. The liquid crystal driving device according to claim 6, further comprising an FRC, wherein said voltages for displaying for halftones corresponding to the number of voltages for input gray levels being in short supply caused by setting of the overshooting driving voltages for transition to a higher voltage and for transition to a lower voltage are generated, by using said FRC, from said voltages for displaying corresponding to higher and lower gray levels of halftones being in short supply.

13. A liquid crystal driving device comprising: an active matrix type of liquid crystal panel whose transmittance changes depending on an applied voltage; anda source driving means to apply a voltage for displaying set according to a gray level of an input signal to said liquid crystal panel with timing determined by an input signal, the voltage for displaying applied to a source electrode of a thin film transistor corresponding to a picture element making up said liquid crystal panel;wherein, said source driving means applies an overshooting driving voltage for transition to a higher voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a highest-level voltage out of voltages for displaying corresponding to a range of input gray levels, which is added to a voltage side being higher than said highest-level voltage out of said voltages for displaying, to said liquid crystal panel; andwherein, said source driving means applies an overshooting driving voltage for transition to a lower voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be said lowest-level voltage out of voltages for displaying corresponding to a range of input gray levels, which is added to a voltage side being lower than said lowest-level voltage out of said voltages for displaying, to said liquid crystal panel.

14. A liquid crystal driving device comprising: an active matrix type of liquid crystal panel whose transmittance changes depending on an applied voltage; anda source driving means to apply a voltage for displaying set according to a gray level of an input signal to said liquid crystal panel with timing determined by an input signal, the voltage for displaying applied to a source electrode of a thin film transistor corresponding to a picture element making up said liquid crystal panel;wherein said source driving means applies an overshooting driving voltage for transition to a higher (or lower) voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a highest-level (or lowest-level) voltage out of voltages for displaying corresponding to a range of input gray levels, which is added to a voltage side being higher (or lower) than said highest-level (or lowest-level) voltage out of said voltages for displaying to said liquid crystal panelwherein said source driving means controls said voltages for displaying being higher (or lower) by voltages corresponding to m (m is a natural number) gray levels from the lowest-level (or highest-level) voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a lowest-level (or highest-level) voltage out of said voltages for displaying corresponding to a range of input gray levels; andwherein said source driving means uses voltages between a voltage being higher (or lower) by voltages corresponding to m gray levels from said lowest-level (or highest-level) voltage and said lowest-level (or highest-level) voltage as an overshooting driving voltage for a transition to a lower (or higher) voltage.

15. A liquid crystal driving device comprising: an active matrix type of liquid crystal panel whose transmittance changes depending on an applied voltage; anda source driving means to apply a voltage for displaying set according to a gray level of an input signal to said liquid crystal panel with timing determined by an input signal, the voltage for displaying applied to a source electrode of a thin film transistor corresponding to a picture element making up said liquid crystal panel;wherein said source driving means applies an overshooting driving voltage for transition to a higher (or lower) voltage, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a highest-level (or lowest-level) voltage out of voltages for displaying corresponding to a range of input gray levels, which is added to a voltage side being higher (or lower) than said highest-level (or lowest-level) voltage out of said voltages for displaying, to said liquid crystal panel;wherein, when the voltage for displaying to be applied to said liquid crystal panel is controlled so as to be a lowest-level (or highest-level) voltage out of said voltages for displaying corresponding to a range of input gray levels, no overshooting driving operation is performed.