Display device and driving method thereof

• US 20070279359A1
• Filed: 05/04/2007
• Published: 12/06/2007
• Est. Priority Date: 06/02/2006
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yoshida, Yasunori, Kimura, Hajime
• Granted Patent: US 8,106,865 B2
• Time in Patent Office: Days
• US Class Current: 345/89
• CPC Class Codes: G02F 1/0121 Operation of devices; Circuit arrangements, not otherwise provided for in this subclass
• CPC Class Codes: G09G 2300/0876 Supplementary capacities in pixels having special driving circuits and electrodes instead of being connected to common electrode or ground; Use of additional capacitively coupled compensation electrodes
• 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 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• 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 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• 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 3/2025 the sub-frames having all the same time duration
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
• CPC Class Codes: G09G 5/10 Intensity circuits

Abstract

It is an object of the present invention to provide a display device in which problems such as an increase of power consumption and increase of a load of when light is emitted are reduced by using a method for realizing pseudo impulsive driving by inserting an dark image, and a driving method thereof. A display device which displays a gray scale by dividing one frame period into a plurality of subframe periods, where one frame period is divided into at least a first subframe period and a second subframe period; and when luminance in the first subframe period to display the maximum gray scale is Lmax1 and luminance in the second subframe period to display the maximum gray scale is Lmax2, (½) Lmax2<Lmax1<( 9/10) Lmax2 is satisfied in the one frame period, is provided.

Claims

1. A display device,

wherein a frame period is divided into at least a first subframe period and a second subframe period, and

wherein, when the frame period displays a maximum gray scale, a first luminance Lmax1 in the first subframe period and a second luminance Lmax2 in the second subframe period satisfy (½

) Lmax<

Lmax1<

( 9/10) Lmax2.

2. A display device according to claim 1,

wherein the frame period is divided into at least the first subframe period, the second subframe period, and a third subframe period, and

wherein, when the frame period displays the maximum gray scale, a maximum luminance Lmax3 in the third subframe period is less than or equal to 1/10 of a maximum luminance in the first subframe period and a maximum luminance in the second subframe period.

3. A display device according to claim 1, wherein the display device comprising an overdrive circuit.

4. A display device according to claim 1, wherein the display device comprising a backlight unit which is scanned while changing the luminance.

5. A display device according to claim 1, wherein the display device comprising a common line which controls one of the first luminance or the second luminance, or both of them.

6. A display device according to claim 1, wherein the display device comprising a display element which is driven by a current.

7. A display device according to claim 1, wherein the display device comprising a liquid crystal of a TN (Twisted Nematic) mode.

8. A display device according to claim 1, wherein the display device comprising a liquid crystal of an MVA (Multi-domain Vertical Alignment) mode.

9. A display device according to claim 1, wherein the display device comprising a liquid crystal of a PVA (Patterned Vertical Alignment) mode.

10. A display device according to claim 1, wherein the display device comprising a liquid crystal of an IPS (In-Plane-Switching) mode.

11. A display device according to claim 1, wherein the display device comprising a liquid crystal of an FFS (Fringe Field Switching) mode.

12. An electronic device using the display device according to claim 1.

24. An electronic device using the display device according to claim 2.

13. A display device,

wherein a frame period is divided into at least a first subframe period and a second subframe period, and

wherein, when the frame period displays a maximum gray scale, a first luminance Lmax1 in the first subframe period and a second luminance Lmax2 in the second subframe periodsatisfy (½

) Lmax1<

Lmax2<

( 9/10) Lmax1.

14. A display device according to claim 13,

wherein the frame period is divided into at least the first subframe period, the second subframe period, and a third subframe period, and

wherein, when the frame period displays the maximum gray scale, a maximum luminance Lmax3 in the third subframe period is less than or equal to 1/10 of a maximum luminance in the first subframe period and a maximum luminance in the second subframe period.

15. A display device according to claim 13, wherein the display device comprising an overdrive circuit.

16. A display device according to claim 13, wherein the display device comprising a backlight unit which is scanned while changing the luminance.

17. A display device according to claim 13, wherein the display device comprising a common line which controls one of the first luminance or the second luminance, or both of them.

18. A display device according to claim 13, wherein the display device comprising a display element which is driven by a current.

19. A display device according to claim 13, wherein the display device comprising a liquid crystal of a TN (Twisted Nematic) mode.

20. A display device according to claim 13, wherein the display device comprising a liquid crystal of an MVA (Multi-domain Vertical Alignment) mode.

21. A display device according to claim 13, wherein the display device comprising a liquid crystal of a PVA (Patterned Vertical Alignment) mode.

22. A display device according to claim 13, wherein the display device comprising a liquid crystal of an IPS (In-Plane-Switching) mode.

23. A display device according to claim 13, wherein the display device comprising a liquid crystal of an FFS (Fringe Field Switching) mode.

25. A display device,

wherein a frame period is divided into at least a first subframe period and a second subframe period,

wherein gray scales which can be displayed include divided n (n is an integer number greater than 1) gray scale regions, and

wherein, in each of the gray scale regions, a luminance change with respect to a gray scale change is constant in either the first subframe period or the second subframe period, or a ratio between first luminance in the first subframe period and second luminance in the second subframe period is constant with respect to a gray scale.

26. A display device according to claim 25,

wherein the frame period is divided into at least the first subframe period, the second subframe period, and a third subframe period, and

wherein, when the frame period displays the maximum gray scale, a maximum luminance Lmax3 in the third subframe period is less than or equal to 1/10 of a maximum luminance in the first subframe period and a maximum luminance in the second subframe period.

27. A display device according to claim 25, wherein the display device comprising an overdrive circuit.

28. A display device according to claim 25, wherein the display device comprising a backlight unit which is scanned while changing the luminance.

29. A display device according to claim 25, wherein the display device comprising a common line which controls one of the first luminance or the second luminance, or both of them.

30. A display device according to claim 25, wherein the display device comprising a display element which is driven by a current.

31. A display device according to claim 25, wherein the display device comprising a liquid crystal of a TN (Twisted Nematic) mode.

32. A display device according to claim 25, wherein the display device comprising a liquid crystal of an MVA (Multi-domain Vertical Alignment) mode.

33. A display device according to claim 25, wherein the display device comprising a liquid crystal of a PVA (Patterned Vertical Alignment) mode.

34. A display device according to claim 25, wherein the display device comprising a liquid crystal of an IPS (In-Plane-Switching) mode.

35. A display device according to claim 25, wherein the display device comprising a liquid crystal of an FFS (Fringe Field Switching) mode.

36. An electronic device using the display device according to claim 25.

37. A driving method of a display device for displaying an image by a plurality of display elements which are juxtaposed,

wherein a frame period is divided into a first subframe period and a second subframe period, and

wherein, when the frame period displays a maximum gray scale, a first luminance Lmax1 in the first subframe period and a second luminance Lmax2 in the second subframe period satisfy (½

) Lmax2<

Lmax1<

( 9/10) Lmax2.

38. A driving method of a display device according to claim 37,

wherein the frame period is divided into at least the first subframe period, the second subframe period, and a third subframe period, and

wherein, when a maximum luminance in the third subframe period is Lmax3, Lmax3 is less than or equal to 1/10 of a maximum luminance in the first subframe period and a maximum luminance in the second subframe period.

39. A driving method of a display device for displaying an image by a plurality of display elements which are juxtaposed,

wherein a frame period is divided into a first subframe period and a second subframe period, and

wherein, when the frame period displays a maximum gray scale, a first luminance Lmax1 in the first subframe period and a second luminance Lmax2 in the second subframe period satisfy (½

) Lmax1<

Lmax2<

( 9/10) Lmax1.

40. A driving method of a display device according to claim 39,

wherein the frame period is divided into at least the first subframe period, the second subframe period, and a third subframe period, and

wherein, when a maximum luminance in the third subframe period is Lmax3, Lmax3 is less than or equal to 1/10 of a maximum luminance in the first subframe period and a maximum luminance in the second subframe period.

41. A driving method of a display device for displaying an image by a plurality of display elements which are juxtaposed,

wherein a frame period is divided into a first subframe period and a second subframe period,

wherein a gray scale which can be displayed include divided n (n is an integer number greater than 1) gray scale regions, and

wherein, in each of the gray scale regions, a luminance change with respect to a gray scale change is constant in either the first subframe period or the second subframe period, or a ratio between first luminance in the first subframe period and second luminance in the second subframe period is constant with respect to a gray scale.

42. A driving method of a display device according to claim 41,

wherein the frame period is divided into at least the first subframe period, the second subframe period, and a third subframe period, and

wherein, when a maximum luminance in the third subframe period is Lmax3, Lmax3 is less than or equal to 1/10 of a maximum luminance in the first subframe period and a maximum luminance in the second subframe period.