Liquid crystal display device, and method of driving the same

• US 20020109659A1
• Filed: 02/07/2002
• Published: 08/15/2002
• Est. Priority Date: 02/08/2001
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Hiroki, Masaaki
• Granted Patent: US 7,535,448 B2
• Time in Patent Office: Days
• US Class Current: 345/92
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2025 the sub-frames having all the same time duration
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

Provided is a liquid crystal display device making it possible to display highly minute images wherein flickers and afterimages are reduced, and a method of driving the same.

Respective picture signals supplied in subframe periods are changed to enlarge the following: a voltage difference between the gradation voltage of a picture signal D_1a supplied in the first subframe period (1st Tsf) and the gradation voltage of a picture signal D_1b supplied in the second subframe period (2nd Tsf). Such voltages are continuously supplied to pixels.

Claims

1. A method of driving a liquid crystal display device comprising plural pixels, a driving circuit for supplying picture signals to the pixels, and a liquid crystal whose transmittivity is changed dependently on the voltage of the picture signals supplied to the pixels, the method comprising the steps of:

dividing one frame into plural subframes;

changing respective voltages of picture signals supplied in plural subframe periods so as to enlarge a voltage difference between a first picture signal supplied to the pixels in at least one subframe period and a second picture signal supplied to the pixels in the other one subframe period adjacent to the one subframe period on the basis of time; and

displaying one frame by displaying the plural subframes successively on the basis of time.

4. The method of driving the liquid crystal display device according to any one of claims 1 to 3, wherein the period for each of the frames is {fraction (1/60)} second.

5. The method of driving, the liquid crystal display device according to any one of claims 1 to 3, wherein each of the subframe periods is {fraction (1/120)} second.

6. The method of driving the liquid crystal display device according to any one of claims 1 to 3, wherein the period for each of the frames is {fraction (1/24)} second.

7. The method of driving the liquid crystal display device according any one of claims 1 to 3, wherein the period for each of the frames is {fraction (1/48)} second.

8. The method of driving the liquid crystal display device according to any one of claims 1 to 3, wherein the period for each of the frames is {fraction (1/96)} second.

9. The method of driving the liquid crystal display device according to any one of claims 1 to 3, wherein the liquid crystal display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a head mount display, a car navigation system, a projector, a car stereo, a personal computer, and portable data terminals.

2. A method of driving a liquid crystal display device comprising plural pixels, a driving circuit for supplying picture signals to the pixels, and a liquid crystal whose transmittivity is changed dependently on the voltage of the picture signals supplied to the pixels, the method comprising the steps of:

dividing one frame into two subframes;

changing respective voltages of picture signals supplied in two subframe periods so as to enlarge a voltage difference between a picture signal supplied to the pixels in one subframe period and a picture signal supplied to the pixels in the other subframe period; and

displaying one frame by displaying the two subframes successively on the basis of time.

3. A method of driving a liquid crystal display device comprising the steps of:

dividing one frame into plural subframes;

changing respective voltages of picture signals supplied in plural subframe periods so as to enlarge a voltage difference between a first picture signal supplied to the pixels in a first subframe period and a second picture signal supplied to the pixels in a second subframe period adjacent to the first adjacent period on the basis of time; and

displaying one frame by displaying the first and second subframes successively on the basis of time.

10. A liquid crystal display device comprising:

plural pixels;

a driving circuit for supplying picture signals to the pixels;

a liquid crystal whose transmittivity is changed dependently on the voltage of the picture signals supplied to the pixels;

means for dividing one frame to plural subframes, and dividing picture signals supplied in each of frame periods to picture signals supplied in plural subframe periods;

means for changing respective voltages of picture signals supplied in plural subframe periods so as to enlarge a voltage difference between a first picture signal supplied to the pixels in one subframe period and a second picture signal supplied to the pixels in the other one subframe period adjacent to the one subframe period on the basis of time; and

means for display one frame by displaying the subframes successively on the basis of time.

13. The method of driving the liquid crystal display device according to any one of claims 10 to 12, wherein the period for each of the frames is {fraction (1/60)} second.

14. The method of driving the liquid crystal display device according to any one of claims 10 to 12, wherein each of the subframe periods is {fraction (1/120)} second.

15. The method of driving the liquid crystal display device according to any one of claims 10 to 12, wherein the period for each of the frames is {fraction (1/24)} second.

16. The method of driving the liquid crystal display device according any one of claims 10 to 12, wherein the period for each of the frames is {fraction (1/48)} second.

17. The method of driving the liquid crystal display device according to any one of claims 10 to 12, wherein the period for each of the frames is {fraction (1/96)} second.

18. The method of driving the liquid crystal display device according to any one of claims 10 to 12, wherein the liquid crystal display device is incorporated into an electronic equipment selected from the group consisting of a video camera, a digital camera, a head mount display, a car navigation system, a projector, a car stereo, a personal computer, and portable data terminals.

11. A liquid crystal display device comprising:

plural pixels;

a driving circuit for supplying picture signals to the pixels;

a liquid crystal whose transmittivity is changed dependently on the voltage of the picture signals supplied to the pixels;

means for dividing one frame into two subframes;

means for dividing picture signals supplied in each of frame periods to picture signals supplied in two subframe periods;

means for changing respective voltages of picture signals supplied in two subframe periods so as to enlarge a voltage difference between a picture signal supplied to the pixels in one subframe period and a picture signal supplied to the pixels in the other one the subframe period; and

means for displaying one frame by displaying the two subframes successively on the basis of time.

12. A liquid crystal display device comprising:

means for dividing one frame into two subframes;

means for dividing picture signals supplied in each of frame periods to picture signals supplied in two subframe periods;

means for changing respective voltages of picture signals supplied in two subframe periods so as to enlarge a voltage difference between a first picture signal supplied to the pixels in a first subframe period and a second picture signal supplied to the pixels in a second subframe period; and

means for displaying one frame by displaying the first and second subframes successively on the basis of time.