Liquid Crystal Display Device and Driving Method Thereof

• US 20080284719A1
• Filed: 05/14/2008
• Published: 11/20/2008
• Est. Priority Date: 05/18/2007
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yoshida, Yasunori
• Granted Patent: US 9,035,867 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/13392 spacers dispersed on the cell substrate, e.g. spherical particles, microfibres
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/13613 the semiconductor element being formed on a first substrate and thereafter transferred to the final cell substrate
• CPC Class Codes: G02F 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element
• CPC Class Codes: G02F 1/136277 formed on a semiconductor substrate, e.g. of silicon
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• 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 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 27/1214 : comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1266 : the substrate on which the devices are formed not being the final device substrate, e.g. using a temporary substrate

Abstract

In a display device including a backlight and a display panel, the area of the backlight is divided into a plurality of unit regions; the display panel includes pixels which are larger in number than the unit regions; a frame rate of image data input to the device is converted to perform display while part of the unit regions in which black is displayed is in a non-light emission state; and the driving frequency of the backlight is converted in accordance with the display.

Claims

1. A liquid crystal display device comprising:

a backlight; and

a display panel,

wherein the backlight is divided into a plurality of unit regions configured so that brightness of each unit region is individually controlled,

wherein the display panel includes pixels which are larger in number than the unit regions,

wherein the display panel is configured to display a first image, a second image, and a third image which is an intermediate state estimated by detecting the amount of change in movement from the first image to the second image,

wherein the backlight is configured to have a period during which brightness of each unit region is controlled in accordance with the first, second, and third images displayed on the display panel, and

wherein the backlight is configured so that a light-emitting state of the backlight is controlled in the same cycle as a display cycle of the first, second, and third images displayed on the display panel.

6. The liquid crystal display device according to claim 1,

wherein the backlight has three levels of brightness,

wherein the display panel has n levels (n is an integer of 2 or more) of brightness, and

wherein.

10. The liquid crystal display device according to claim 1, wherein the backlight is configured so that brightness is controlled in accordance with an average value of brightness of the first, second, and third images of image data input to the liquid crystal display device.

15. The liquid crystal display device according to claim 1, wherein the display panel is configured so that overdrive voltage is input to the display panel.

20. The liquid crystal display device according to claim 1, wherein the display panel is configured so that voltage whose polarity is switched periodically is input to the display panel.

2. A liquid crystal display device comprising:

a backlight; and

a display panel,

wherein the backlight is divided into a plurality of unit regions configured so that brightness of each unit region is individually controlled,

wherein the display panel includes pixels which are larger in number than the unit regions,

wherein the display panel is configured to display a first image, a second image, and a third image in this order,

wherein a whole display region is the same display state in the second image,

wherein the backlight is configured to have a period during which brightness of each unit region is controlled in accordance with the first and third images displayed on the display panel, and

wherein the backlight is configured so that a light-emitting state of the backlight is controlled in a cycle which is longer than a display cycle of the first, second, and third images displayed on the display panel.

7. The liquid crystal display device according to claim 2,

wherein the backlight has three levels of brightness,

wherein the display panel has n levels (n is an integer of 2 or more) of brightness, and

wherein the liquid crystal display device is configured to display lager than n levels of brightness as a whole.

11. The liquid crystal display device according to claim 2, wherein the backlight is configured so that brightness is controlled in accordance with an average value of brightness of the first, second, and third images of image data input to the liquid crystal display device.

16. The liquid crystal display device according to claim 2, wherein the display panel is configured so that overdrive voltage is input to the display panel.

21. The liquid crystal display device according to claim 2, wherein the display panel is configured so that voltage whose polarity is switched periodically is input to the display panel.

3. A liquid crystal display device comprising:

a backlight; and

a display panel,

wherein the backlight is divided into a plurality of unit regions configured so that brightness of each unit region is individually controlled,

wherein the display panel includes pixels which are larger in number than the unit regions,

wherein the display panel is configured so that display states of a first image and a second image displayed on the display panel are controlled in the same cycle as image data input to the liquid crystal display device,

wherein the backlight is configured to have a period during which brightness of each unit region is controlled in accordance with the first and second images displayed on the display panel,

wherein the backlight is configured to provide a third image between the first image and the second image,

wherein a whole display region is the same display state in the display panel in the third image, and

wherein the backlight is configured so that a light-emitting state of the backlight is controlled in a cycle which is shorter than a display cycle of the first and second images displayed on the display panel.

8. The liquid crystal display device according to claim 3,

wherein the backlight has three levels of brightness,

wherein the display panel has n levels (n is an integer of 2 or more) of brightness, and

wherein the liquid crystal display device is configured to display lager than n levels of brightness as a whole.

12. The liquid crystal display device according to claim 3, wherein the backlight is configured so that brightness is controlled in accordance with an average value of brightness of the first and second images of image data input to the liquid crystal display device.

17. The liquid crystal display device according to claim 3, wherein the display panel is configured so that overdrive voltage is input to the display panel.

22. The liquid crystal display device according to claim 3, wherein the display panel is configured so that voltage whose polarity is switched periodically is input to the display panel.

4. A liquid crystal display device comprising:

a backlight; and

a display panel,

wherein the backlight is divided into a plurality of unit regions configured so that brightness of each unit region is individually controlled,

wherein the display panel includes pixels which are larger in number than the unit regions,

wherein the display panel is configured to display a first image, a second image, and a third image in this order,

wherein a whole display region is the same display state in the second image,

wherein the backlight is configured to have a period during which brightness of each unit region is controlled in accordance with the image displayed on the display panel,

wherein the backlight is configured to provide the second image on the display panel, and

wherein the backlight is configured so that a light-emitting state is controlled in the same cycle as a display cycle of the first, second, and third images displayed on the display panel.

9. The liquid crystal display device according to claim 4,

wherein the backlight has three levels of brightness,

wherein the display panel has n levels (n is an integer of 2 or more) of brightness, and

wherein the liquid crystal display device is configured to display lager than n levels of brightness as a whole.

13. The liquid crystal display device according to claim 4, wherein the backlight is configured so that brightness is controlled in accordance with an average value of brightness of the first, second, and third images of image data input to the liquid crystal display device.

18. The liquid crystal display device according to claim 4, wherein the display panel is configured so that overdrive voltage is input to the display panel.

23. The liquid crystal display device according to claim 4, wherein the display panel is configured so that voltage whose polarity is switched periodically is input to the display panel.

5. A liquid crystal display device comprising:

a backlight; and

a display panel,

wherein the backlight is divided into a plurality of unit regions configured so that brightness of each unit region is individually controlled,

wherein the display panel includes pixels which are larger in number than the unit regions,

wherein the backlight is configured to have three or more levels of brightness,

wherein the display panel is configured to have n levels (n is an integer of 2 or more) of brightness, and

wherein the liquid crystal display device is configured to display lager than n levels of brightness as a whole.

14. The liquid crystal display device according to claim 5, wherein the backlight is configured so that brightness is controlled in accordance with an average value of brightness of images of image data input to the liquid crystal display device.

19. The liquid crystal display device according to claim 5, wherein the display panel is configured so that overdrive voltage is input to the display panel.

24. The liquid crystal display device according to claim 5, wherein the display panel is configured so that voltage whose polarity is switched periodically is input to the display panel.