Liquid crystal driver, liquid crystal driving method and liquid crystal display device

• US 20080284707A1
• Filed: 10/17/2007
• Published: 11/20/2008
• Est. Priority Date: 11/01/2006
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Morita, Hideo, Shirochi, Yoshiki, Katagawa, Koichi, Kawaura, Hideaki
• Granted Patent: US 8,823,623 B2
• Time in Patent Office: Days
• US Class Current: 345/96
• CPC Class Codes: G01K 13/00 Thermometers specially adapted for specific purposes
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• 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 driver is provided, in which a frame rate of an input image signal is multiplied by 2N (N is an integer of one or more); each frame is divided into N positive field(s) and N negative field(s) respectively; the image signal is supplied to a liquid crystal panel with a positive polarity in a positive field; and the image signal is supplied to the liquid crystal panel with a negative polarity in a negative field. The liquid crystal driver includes a corrected image signal generator configured to generate a corrected image signal having the same amount of correction added to the positive field and negative field. The corrected image signal is supplied to the liquid crystal panel with the positive polarity in the positive field and the corrected image signal is supplied to the liquid crystal panel with the negative polarity in the negative field.

Claims

1. A liquid crystal driver, in which a frame rate of an input image signal is multiplied by 2N (N is an integer of one or more), each frame is divided into N positive field(s) and N negative field(s) respectively, the image signal is supplied to a liquid crystal panel with a positive polarity in a positive field, and the image signal is supplied to the liquid crystal panel with a negative polarity in a negative field, comprising:

corrected image signal generating portion for generating a corrected image signal having the same amount of correction added to the positive field and the negative field in response to a luminance of the image signal of the N positive field(s) and N negative field(s) respectively divided from the each frame and a luminance of the image signal 2N fields before the respective positive field and negative field, wherein

the corrected image signal generated by the corrected image signal generating portion is supplied to the liquid crystal panel with the positive polarity in the positive field and the corrected image signal generated by the corrected image signal generating portion is supplied to the liquid crystal panel with the negative polarity in the negative field.

2. A liquid crystal driver according to claim 1, further comprising

a detector configured to detect the temperature of the liquid crystal panel, wherein

the corrected image signal generating portion generates the corrected image signal such that the amount of correction becomes small as the temperature detected by the detector becomes high.

3. A liquid crystal driving method, in which a frame rate of an input image signal is multiplied by 2N (N is an integer of one or more), each frame is divided into N positive field(s) and N negative field(s) respectively, the image signal is supplied to a liquid crystal panel with a positive polarity in a positive field, and the image signal is supplied to the liquid crystal panel a negative polarity in a negative field, comprising the steps of:

generating a corrected image signal having the same amount of correction added to the positive field and the negative field in response to a luminance of the image signal of the N positive field(s) and N negative field(s) respectively divided from the each frame and a luminance of the image signal 2N fields before the respective positive field and negative field, and

supplying the corrected image signal generated at the generating step to the liquid crystal panel with the positive polarity in the positive field and the corrected image signal generated at the generating step to the liquid crystal panel with the negative polarity in the negative field.

4. A liquid crystal driving method according to claim 3, further comprising the step of

detecting the temperature of the liquid crystal panel, wherein

the corrected image signal is generated at the generating step such that the amount of correction becomes small as the temperature detected at the detecting step becomes high.

5. A liquid crystal display device comprising:

a liquid crystal panel, and

a drive circuit in which a frame rate of an input image signal is multiplied by 2N (N is an integer of one or more), each frame is divided into N positive field(s) and N negative field(s) respectively, the image signal is supplied to the liquid crystal panel with a positive polarity in a positive field, and the image signal is supplied to the liquid crystal panel with a negative polarity in a negative field, wherein

the drive circuit includes

a corrected image signal generator configured to generate a corrected image signal having the same amount of correction added to the positive field and the negative field in response to a luminance of the image signal of the N positive field(s) and N negative field(s) respectively divided from the each frame and a luminance of the image signal 2N fields before the respective positive field and negative field, and

the corrected image signal generated by the corrected image signal generator is supplied to the liquid crystal panel with the positive polarity in the positive field and the corrected image signal generated by the corrected image signal generator is supplied to the liquid crystal panel with the negative polarity in the negative field.

6. A liquid crystal display device according to claim 5, further comprising

a detector configured to detect the temperature of the liquid crystal panel, wherein

the corrected image signal generator generates the corrected image signal such that the amount of correction becomes small as the temperature detected by the detector becomes high.

7. A liquid crystal driver, in which a frame rate of an input image signal is multiplied by 2N (N is an integer of two or more), each frame is divided into N positive fields and N negative fields respectively, the image signal is supplied to a liquid crystal panel with a positive polarity in a positive field, and the image signal is supplied to the liquid crystal panel with a negative polarity in a negative field, comprising:

corrected image signal generating portion for generating a corrected image signal for the positive field and the negative field in response to a luminance of the image signal of the N positive fields and N negative fields respectively divided from the each frame and a luminance of the image signal 2N fields before the respective positive field and negative field, said corrected image signal generating portion adding a predetermined amount of correction to a front field alone among the N fields out of the positive fields and negative fields. supplying first the image signal to the liquid crystal panel, and dividing and adding the predetermined amount of correction to two or more fields out of the positive fields and negative fields not supplying first the image signal to the liquid crystal panel, wherein

the corrected image signal generated by the corrected image signal generating portion is supplied to the liquid crystal panel with the positive polarity in the positive field and the corrected image signal generated by the corrected image signal generating portion is supplied to the liquid crystal panel with the negative polarity in the negative field.

8. A liquid crystal driver according to claim 7, further comprising

a detector configured to detect the temperature of the liquid crystal panel, wherein

the corrected image signal generating portion generates the corrected image signal such that the amount of correction becomes small as the temperature detected by the detector becomes high.

9. A liquid crystal driving method, in which a frame rate of an input image signal is multiplied by 2N (N is an integer of two or more), each frame is divided into N positive fields and N negative fields respectively, the image signal is supplied to a liquid crystal panel with a positive polarity in a positive field, and the image signal is supplied to the liquid crystal panel with a negative polarity in a negative field, comprising the steps of:

generating a corrected image signal for the positive field and the negative field in response to a luminance of the image signal of the N positive fields and N negative fields respectively divided from the each frame and a luminance of the image signal 2N fields before the positive field and negative field;

adding a predetermined amount of correction to a front field among the N fields out of the positive fields and negative fields supplying first the image signal to the liquid crystal panel;

dividing and adding the predetermined amount of correction to two or more fields out of the positive fields and negative fields not supplying first the image signal to the liquid crystal panel; and

supplying the corrected image signal generated at the preceding steps to the liquid crystal panel with the positive polarity in the positive field and the corrected image signal generated at the preceding steps to the liquid crystal panel with the negative polarity in the negative field.

10. A liquid crystal driving method according to claim 9, further comprising the step of

detecting the temperature of the liquid crystal panel, wherein

the corrected image signal is generated at generating, adding, and dividing and adding steps such that the amount of correction becomes small as the temperature detected at the detecting step becomes high.

11. A liquid crystal display device comprising:

a liquid crystal panel, and

a drive circuit in which a frame rate of an input image signal is multiplied by 2N (N is an integer of two or more), each frame is divided into N positive fields and N negative fields respectively, the image signal is supplied to the liquid crystal panel with the positive polarity in a positive field, and the image signal is supplied to the liquid crystal panel with the negative polarity in a negative field, wherein

the drive circuit includes

a corrected image signal generator configured to generate a corrected image signal for the positive field and negative field in response to a luminance of the image signal including the N positive fields and N negative fields respectively divided from the each frame and a luminance of the image signal 2N fields before the positive field and negative field, to add a predetermined amount of correction to a front field alone among the N fields out of the positive fields and negative fields supplying first the image signal to the liquid crystal panel and to divide and add the predetermined amount of correction to two or more fields out of the positive fields and negative fields not supplying first the image signal to the liquid crystal panel, and

the corrected image signal generated by the corrected image signal generator is supplied to the liquid crystal panel with the positive polarity in the positive field and the corrected image signal generated by the corrected image signal generator is supplied to the liquid crystal panel with the negative polarity in the negative field.

12. A liquid crystal display device according to claim 11, further comprising

a detector to detect the temperature of the liquid crystal panel, wherein

the corrected image signal generator generates the corrected image signal such that the amount of correction becomes small as the temperature detected by the detector becomes high.

13. A driver for a liquid crystal panel, multiplying a frame rate of an input image signal by 2N (N is an integer of one or more), dividing each frame into N positive field(s) and N negative field(s) respectively, and supplying the image signal to the liquid crystal panel with a positive polarity in a positive field and with a negative polarity in a negative field, said driver comprising:

a corrected image signal generator configured to generate a corrected image signal having the same amount of correction added to the positive field and the negative field in response to a luminance of the image signal of the N positive field(s) and N negative field(s) respectively divided from the each frame and a luminance of the image signal 2N fields before the respective positive field and negative field, wherein

the corrected image signal generated by the corrected image signal generator is supplied to the liquid crystal panel with the positive polarity in the positive field and the corrected image signal generated by the corrected image signal generator is supplied to the liquid crystal panel with the negative polarity in the negative field.

14. A driver for a liquid crystal panel, multiplying a frame rate of an input image signal by 2N (N is an integer of one or more), dividing each frame into N positive field(s) and N negative field(s) respectively, and supplying the image signal to the liquid crystal panel with a positive polarity in a positive field and with a negative polarity in a negative field, said driver comprising:

a corrected image signal generator configured to generate a corrected image signal for the positive field and the negative field in response to a luminance of the image signal of the N positive fields and N negative fields respectively divided from the each frame and a luminance of the image signal 2N fields before the respective positive field and negative field, said corrected image signal generator configured to add a predetermined amount of correction to a front field alone among the N fields out of the positive fields and negative fields supplying first the image signal to the liquid crystal panel, and divide and add the predetermined amount of correction to two or more fields out of the positive fields and negative fields not supplying first the image signal to the liquid crystal panel, wherein

the corrected image signal generated by the corrected image signal generator is supplied to the liquid crystal panel with the positive polarity in the positive field and the corrected image signal generated by the corrected image signal generator is supplied to the liquid crystal panel with the negative polarity in the negative field.