Liquid crystal display apparatus, driving method for same, and driving circuit for same

• US 8,836,621 B2
• Filed: 12/15/2005
• Issued: 09/16/2014
• Est. Priority Date: 12/15/2004
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd.
• Original Assignee: NLT Technologies, Ltd.
• Inventors: Takatori, Kenichi, Sekine, Hiroyuki, Sumiyoshi, Ken
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): Shapiro, Leonid
• Application Number:
  US11/300,483
• Publication Number:
  US 20060145978A1
• Time in Patent Office: 3,197 Days
• Field of Search: 345/87, 345/55, 345 98-100
• US Class Current: 345/87
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• 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 2310/0235 Field-sequential colour display
• 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 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/041 Temperature compensation
• 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 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors

Abstract

The liquid crystal display apparatus is provided with a display unit, a video signal driving circuit, a scanning signal driving circuit, a common electrode potential controlling circuit, and a synchronizing circuit. The display unit has a scanning electrode, a video signal electrode, a plurality of pixel electrodes arranged in matrix form, a plurality of switching elements which transmit video signals to the pixel electrodes, and a common electrode. After the scanning signal driving circuit scans the entire scanning electrodes and transmits video signals to the pixel electrodes, the common electrode potential controlling circuit changes the potential of the common electrode into a pulse shape, overdrives video signals, or increases a torque required to return to a state in which no voltage is applied.

Claims

1. A liquid crystal display apparatus comprising:

a liquid crystal display unit;

a video signal driving circuit;

a scanning signal driving circuit;

a storage capacitance electrode potential controlling circuit; and

a synchronizing circuit,

wherein the display unit has

a scanning electrode,

a video signal electrode,

a plurality of pixel electrodes arranged in matrix form,

a plurality of switching elements which transmit video signals to the pixel electrodes,

a common electrode, and

a storage capacitance electrode, and

wherein the storage capacitance electrode potential controlling circuit changes the potential of the storage capacitance electrode into a pulse shape after the scanning signal driving circuit scans the entire scanning electrodes and transmits video signals to the pixel electrodes,

the potentials of the video signals is determined by comparing the hold data of the individual pixels before the writing of the video signals, a variation in the potentials of the pixel electrodes associated with a variation in the potentials of the common electrodes to be changed into a pulse shape, the potentials of the storage capacitance electrodes to be changed into a pulse shape, or the potentials of both of them, and display data to be newly displayed, and,

the comparison of the data and the variation in the potentials is made by using LUTs (look-up tables, correspondence tables) prepared in advance, said LUTs differing from one another according to the polarity of the video signals.

2. The liquid crystal display apparatus according to claim 1, wherein said LUTs differs from one another according also to the colors of light beams of the light irradiating unit changed by synchronizing with the video signals at the predetermined phase, in addition to the polarity of the video signals.

3. The liquid crystal display apparatus according to claim 1, wherein the potential of the storage capacitance electrode changed into a pulse shape is a potential which does not reset display on the display unit.

4. The liquid crystal display apparatus according to claim 1, wherein the potential of the storage capacitance electrode varies between at least three potentials.

5. The liquid crystal display apparatus according to claim 1 wherein the potential of the common electrode or the storage capacitance electrode is changed into a pulse shape so as to temporarily increase a potential difference between the potential of the pixel electrode and the potential of the common electrode or the storage capacitance electrode.

6. The liquid crystal display apparatus according to claim 1 wherein the potential of the video signal is different from the potential of a video signal in a stable state during static driving in consideration of the response characteristics of the display unit during charge holding type driving.

7. The liquid crystal display apparatus according to claim 6 wherein the potential of the video signal is determined by taking into account the response characteristics of the display unit and by comparing the hold data of individual pixels before the writing of the video signal and display data to be newly displayed.

8. The liquid crystal display apparatus according to claim 1 wherein a field response type substance is sandwiched between the pixel electrodes and the common electrode of the display unit.

9. The liquid crystal display apparatus according to claim 8 wherein the field response type substance is made of a liquid crystal substance.

10. The liquid crystal display apparatus according to claim 9 wherein the liquid crystal substance is in an electrically controlled birefringence mode.

11. The liquid crystal display apparatus according to claim 9 wherein the liquid crystal substance is a nematic liquid crystal and has a twisted nematic alignment.

12. The liquid crystal display apparatus according to claim 11 wherein between the twist pitch p (μ

m) of the twisted nematic alignment of the liquid crystal substance and the average thickness d (μ

m) of the layer of the liquid crystal substance having the twisted nematic alignment, a relationship p/d<

20 is established.

13. The liquid crystal display apparatus according to claim 11 wherein the liquid crystal substance having the twisted nematic alignment is stabilized by a polymer having a structure almost continuously twisted.

14. The liquid crystal display apparatus according to claim 12 wherein between the twist pitch p (μ

m) of the twisted nematic alignment of the liquid crystal substance and the average thickness d (μ

m) of the layer of the liquid crystal substance having the twisted nematic alignment, a relationship p/d<

8 is established.

15. The liquid crystal display apparatus according to claim 2 wherein the LUTs (look-up tables, correspondence tables) describe a relationship between input video data and output voltage to the display unit according to the order of the change in the polarity of the video signals and the order of the change in the colors of light beams of the light irradiating unit.

16. The liquid crystal display apparatus according to claim 1 wherein the display unit is provided with a color filter to produce a color display.

17. The liquid crystal display apparatus according to claim 1 wherein a lenticular lens sheet, a lenticular film, or a double-sided prism sheet is provided to the display unit to produce a stereoscopic display.

18. The liquid crystal display apparatus according to claim 1 wherein a color field sequential (color time-sharing) system is used in which a video signal is divided into a plurality of color video signals which correspond to a plurality of colors, light sources corresponding to the plurality of colors are synchronized with the plurality of color video signals at a predetermined phase difference, and the plurality of color video signals are displayed in time sequence.

19. The liquid crystal display apparatus according to claim 18 wherein a stereoscopic display system of the color field sequential (color time-sharing) type is used in which video signals consist of video signals for the right eye and video signals for the left eye, the video signals for one eye are divided into a plurality of color video signals which correspond to a plurality of colors, light sources, which correspond to the colors and which are provided at two places, are synchronized with the video signals for one eye at a predetermined phase difference and are synchronized with the color video signal to display the video signals for one eye in time sequence, and at the same time, the video signals for one eye are displayed in time sequence as a plurality of color video signals divided.

20. The liquid crystal display apparatus according to claim 9 wherein the liquid crystal substance is in a FFS (fringe field switching) mode or an AFFS (advanced fringe field) mode.

21. The liquid crystal display apparatus according to claim 9 wherein the liquid crystal substance is in an IPS (in-plane switching) mode in which the liquid crystal substance responds by the action of an electric field which acts roughly parallel to a substrate surface.

22. The liquid crystal display apparatus according to claim 9 wherein the liquid crystal substance is a ferroelectric liquid crystal substance, an antiferroelectric liquid crystal substance, or a liquid crystal substance exhibiting an electroclinic type response.

23. The liquid crystal display apparatus according to claim 9 wherein the liquid crystal substance is a cholesteric liquid crystal substance.

24. The liquid crystal display apparatus according to claim 9 wherein the liquid crystal substance is stabilized by a polymer having a structure in a state in which no voltage is applied or a low voltage is applied.

25. The liquid crystal display apparatus according to claim 9 wherein the liquid crystal substance is in a VA (vertical alignment) mode in which homeotropic alignment develops.

26. The liquid crystal display apparatus according to claim 25 wherein the liquid crystal substance is provided with multidomains.

27. The liquid crystal display apparatus according to claim 1 wherein the comparison of the data and the variation in the potentials is made in order.

28. The liquid crystal display apparatus according to claim 1 wherein the pixel switch is an amorphous silicon thin film transistor display apparatus which is comprised of a thin film transistor of amorphous silicon.

29. A portable terminal using the liquid crystal display apparatus according to claim 1.

30. A mobile display apparatus using the liquid crystal display apparatus according to claim 1.

31. The liquid crystal display apparatus according to claim 1 wherein the pixel switch is a polycrystalline silicon thin film transistor display apparatus which is comprised of a thin film transistor of polycrystalline silicon.

32. The liquid crystal display apparatus according to claim 1 wherein the pixel switch is comprised of a transistor of a single-crystalline silicon.

33. The liquid crystal display apparatus according to claim 1 wherein the polarity of the video signals is reversed with a predetermined timing, and among the potentials of the common electrodes which varies between a plurality of potentials, one or two potentials whose application time periods are longer than those of the other potentials are approximately equal to an intermediate potential between the maximum potential and the minimum potential of all the potentials applied as the video signals.

34. A driving method for a liquid crystal display apparatus wherein in a driving method for the liquid crystal display apparatus according to claim 33, the common electrode potential varies to four potentials, the first potential being the common electrode potential provided at a time period over which the scanning signal driving circuit scans the scanning electrode to transmit video signals having one polarity of the video signals reversed, the second potential being the potential of the pulse height portion developed when the common electrode potential is changed into a pulse shape following the provision of the first potential, the third potential being a potential, which is developed after the common electrode potential is changed into a pulse shape following the development of the second potential, and the common electrode potential at a time period over which the scanning signal driving circuit scans the scanning electrode to transmit video signals having the other polarity of the video signals reversed, the fourth potential being the potential of the pulse height portion formed when the common electrode potential is changed into a pulse shape following the development of the third potential.

35. The liquid crystal display apparatus according to claim 1 wherein the polarity of the video signals is reversed with a predetermined timing, and among the potentials of the common electrodes which varies between a plurality of potentials, one or two potentials whose application time periods are longer than those of the other potentials are approximately equal to either the maximum potential or the minimum potential of the all the potentials which can be applied as the video signals.

36. A driving method for a liquid crystal display apparatus wherein in a driving method for the liquid crystal display apparatus according to claim 35, the common electrode potential varies to six potentials, the first potential being the common electrode potential provided at a time period over which the scanning signal driving circuit scans the scanning electrode to transmit video signals having one polarity of the video signals reversed, the second potential being the potential of the pulse height portion formed when the common electrode potential is changed into a pulse shape following the provision of the first potential, the third potential being a potential developed after the common electrode potential is changed into a pulse shape following the development of the second potential, the fourth potential is the common electrode potential developed at a time period over which the scanning signal driving circuit scans the scanning electrode to transmits video signals having the other polarity of the video signals reversed, the fifth potential being the potential of the pulse height portion formed when the common electrode potential is changed into a pulse shape following the development of the fourth potential, the sixth potential being a potential developed after the common electrode potential is changed into a pulse shape following the development of the fifth potential.

37. The liquid crystal display apparatus according to claim 1 wherein the common electrode potentials, which are provided immediately before the scanning signal driving circuit starts to scan the scanning electrode, are equal to the common electrode potentials produced immediately after the scanning signal driving circuit scans the entire scanning electrodes and transmits video signals to the pixel electrodes and before the common electrode potentials are changed into a pulse shape.

38. The liquid crystal display apparatus according to claim 1 wherein the common electrode potentials, which are provided immediately before the scanning signal driving circuit starts to scan the scanning electrode, are different from the common electrode potentials produced immediately after the scanning signal driving circuit scans the entire scanning electrodes and transmits video signals to the pixel electrodes and before the common electrode potentials are changed into a pulse shape.

39. The liquid crystal display apparatus according to claim 38 wherein the common electrode potentials, which are provided immediately before the scanning signal driving circuit starts to scan the scanning electrode, are approximately equal to one of a maximum voltage and a minimum voltage which can be produced as video signals to be applied and the common electrode potentials, which are provided immediately after the scanning signal driving circuit scans the entire scanning electrodes and transmits video signals to the pixel electrodes and before the common electrode potentials are changed into a pulse shape, are approximately equal to the other of the maximum voltage and the minimum voltage which can be produced as video signals which have been applied.

40. The liquid crystal display apparatus according to claim 1 having a light irradiating unit, which irradiates the display unit with light, and a synchronizing circuit which synchronizes the intensity of light from the irradiating unit with the video signals at a predetermined phase for modulation.

41. The liquid crystal display apparatus according to claim 40 wherein the light intensity of the light irradiating unit is synchronized with the video signals at a predetermined phase according to the polarity of the video signals for modulation.

42. A driving method for a liquid crystal display apparatus wherein in a driving method for the liquid crystal display apparatus according to claim 40, when the division into individual fields or a plurality of colors is conducted, the timing of modulating the light intensity of the light irradiating unit or of changing the color of the light is present during a fixed time period after the completion of subfield corresponding to the colors or a fixed time period immediately before the writing of the video signals of the next field.

43. The liquid crystal display apparatus according to claim 1 having a light irradiating unit, which irradiates the display unit with light, and a synchronizing circuit which synchronizes the colors of light from the light irradiating unit with the video signals at a predetermined phase to change the colors.

44. A driving method for a liquid crystal display apparatus wherein in a driving method for the liquid crystal display apparatus according to claim 43, when the division into individual fields or a plurality of colors is conducted, the timing of modulating the light intensity of the light irradiating unit or of changing the color of the light is present during a fixed time period after the completion of subfield corresponding to the colors or a fixed time period immediately before the writing of the video signals of the next field.

45. The liquid crystal display apparatus according to claim 1 having a light irradiating unit, which irradiates the display unit with light, and a synchronizing circuit which synchronizes the intensity of light from the light irradiating unit with the video signals at a predetermined phase for modulation and which synchronizes the colors of the light from the light irradiating unit with the video signals at a predetermined phase to change the colors.

46. A driving method for a liquid crystal display apparatus wherein in a driving method for the liquid crystal display apparatus according to claim 45, when the division into individual fields or a plurality of colors is conducted, the timing of modulating the light intensity of the light irradiating unit or of changing the color of the light is present during a fixed time period after the completion of subfield corresponding to the colors or a fixed time period immediately before the writing of the video signals of the next field.

47. The liquid crystal display apparatus according to claim 1, wherein in the change into the pulse shape not to be reset of the liquid crystal display apparatus using the twisted nematic liquid crystal, the mean tilt angle of the liquid crystal during the change into the pulse shape is 81°

or less.

48. The liquid crystal display apparatus according to claim 47 wherein in the change into the pulse shape not to be reset, the mean tilt angle of the liquid crystal during the change into the pulse shape is 65°

or less.

49. The liquid crystal display apparatus according to claim 1, wherein digital signals are used as the video signals, binary signals are used for the potentials applied to the display substance, and the display is produced by using integrated light digital driving in which gradation is represented in a time-base direction.

50. A near-eye apparatus wherein the liquid crystal display apparatus according to claim 1 is used.

51. A projection apparatus wherein the liquid crystal display apparatus according to claim 1 is used in a projection apparatus which projects the base images of a display apparatus by using a projection optical system.

52. A monitoring apparatus using the liquid crystal display apparatus according to claim 1.

53. The liquid crystal display apparatus according to claim 9 wherein the liquid crystal substance has a pie-type alignment (bend-type alignment).

54. The liquid crystal display apparatus according to claim 53 wherein an optically compensated plate is used in an OCB (optically compensated birefringence) mode.

55. The liquid crystal display apparatus according to claim 1, wherein the storage capacitance electrode potential controlling circuit changes the potential of the storage capacitance electrode into a pulse shape only after the scanning signal driving circuit scans the entire scanning electrodes and transmits the video signals to the pixel electrodes.

56. The liquid crystal display apparatus according to claim 1, wherein the hold data is a sum of charges held between the pixel electrode and the storage capacitance electrode.