IP Library Granted Patent US 7,161,577
Granted Patent B2
US 7,161,577 · App. 09/987,595 · Granted Jan 9, 2007

Liquid crystal display device

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Quick Facts
Patent No.
US 7,161,577
App. No.
09/987,595
Granted
Jan 9, 2007
Kind
B2
Abstract

In a liquid crystal display device having a backlight, the backlight has a first state which outputs a first amount of light and a second state which generates a second amount of light and the time for the first state and the time for the second state are controlled. Due to such a constitution, the liquid crystal display device can display clear motion picture images in spite of a simple constitution thereof. Further, the liquid crystal display device can display clear and bright motion picture images.

Claims (25)

1. A liquid display device comprising:

a liquid crystal display panel; and

a backlight unit,

wherein the backlight unit repeats lighting and extinguishing a backlight at a constant refresh rate such that a lighting time period is shorter for a motion picture image with a fast-moving subject captured therein than for a motion picture image with a slow-moving subject captured therein, and

the motion picture images have an identical frame rate.

2. A liquid display device according to claim 1 , further comprising an image movement degree detection circuit.

3. A liquid display device according to claim 2 , further comprising a signal information classifying circuit for classifying signal information into at least a normal movement state and a fast movement state.

4. A liquid display device according to claim 2 , further comprising a signal information classifying circuit for classifying signal information into at least a still picture state and a motion picture state.

5. A liquid display device according to claim 1 , wherein a current of the backlight is increased when the lighting time period becomes shorter.

6. A liquid display device according to claim 1 , wherein the backlight unit includes a lamp, and a current of the lamp is increased when the lighting time period becomes shorter.

7. A liquid display device according to claim 1 , wherein the lighting time period is changed based on an image movement at center of the display panel.

8. A liquid display device according to claim 1 , wherein the repeating of lighting and extinguishing is synchronized with a scanning signal.

9. A liquid display device according to claim 1 , wherein the liquid crystal panel is one of a lateral electric field type, a longitudinal electric field type, and a vertical orientation type, and the longitudinal electric field type has liquid crystal molecules oriented parallel to a surface of a substrate and has a twisted structure.

10. A liquid display device comprising:

a liquid crystal display panel; and

a backlight unit,

wherein the backlight unit controls a backlight to maintain lighting at a constant light amplitude for a still picture image with a non-moving subject captured therein, and repeats lighting and extinguishing for a moving picture image with a moving subject captured therein, and

the still and moving picture images have an identical frame rate.

11. A liquid display device according to claim 10 , wherein further comprising an image movement degree detection circuit.

12. A liquid display device according to claim 11 , further comprising a signal information classifying circuit for classifying signal information into at least a still picture state and a motion picture state.

13. A liquid display device according to claim 10 , wherein a current of the backlight is increased when the lighting time period becomes shorter.

14. A liquid display device according to claim 10 , wherein the backlight unit includes a lamp, and a current of the lamp is increased when the lighting time period becomes shorter.

15. A liquid display device according to claim 10 , wherein the lighting time period is changed based on an image movement at center of the display panel.

16. A liquid display device according to claim 10 , wherein the repeating of lighting and extinguishing is synchronized with a scanning signal.

17. A liquid display device according to claim 10 , wherein the liquid crystal panel is one of a lateral electric field type, a longitudinal electric field type, and a vertical orientation type, and the longitudinal electric field type has liquid crystal molecules oriented parallel to a surface of a substrate and has a twisted structure.

Assignments (3)
COMPANY SPLIT PLAN TRANSFERRING FIFTY (50) PERCENT SHARE OF PATENTS AND PATENT APPLICATIONS Recorded Dec 12, 2011
From: HITACHI DISPLAYS, LTD.
To: IPS ALPHA SUPPORT CO., LTD.
Reel/Frame 027362/0466 →
COMPANY SPLIT PLAN TRANSFERRING ONE HUNDRED (100) PERCENT SHARE OF PATENT AND PATENT APPLICATIONS Recorded Dec 12, 2011
From: HITACHI, LTD.
To: HITACHI DISPLAYS, LTD.
Reel/Frame 027362/0612 →
MERGER/CHANGE OF NAME Recorded Dec 12, 2011
From: IPS ALPHA SUPPORT CO., LTD.
To: PANASONIC LIQUID CRYSTAL DISPLAY CO., LTD.
Reel/Frame 027363/0315 →