Display control device

• US 5,642,128 A
• Filed: 03/01/1995
• Issued: 06/24/1997
• Est. Priority Date: 10/02/1987
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Inoue, Hiroshi
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US08/396,904
• Time in Patent Office: 846 Days
• Field of Search: 350/332, 350/333, 350/350 S, 340/784, 340/805, 359/55, 359/56, 359/85, 359/100, 345/94, 345/95, 345/96, 345/97, 345/209
• US Class Current: 345/96
• CPC Class Codes: G09G 2310/0232 Special driving of display border areas
• CPC Class Codes: G09G 2310/0245 Clearing or presetting the whole screen independently of waveforms, e.g. on power-on G09G2310/063 takes precedence
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/062 Waveforms for resetting a plurality of scan lines at a time
• CPC Class Codes: G09G 2310/065 Waveforms comprising zero voltage phase or pause
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3629 using liquid crystals having memory effects, e.g. ferroelectric liquid crystals

Abstract

A display control device controls a display device provided with a group of scanning electrodes and a group of signal electrodes and a display element placed therebetween. A driver circuit applies a non-zero first scanning signal to a selected one of the group of scanning electrodes during a first period and applies a non-zero second scanning signal to the selected scanning electrode in a second period after the first period. The first and second scanning signals are applied to the selected scanning electrode when a driving signal is applied to a predetermined number of signal electrodes of the group of signal electrodes. The first and second periods are separated by a rest period, and a polarity of a portion of the first scanning signal immediately before the rest period is opposite to a polarity of a portion of the second scanning signal immediately after the rest period.

Claims

1. A display control method for controlling a display device provided with a group of scanning electrodes and a group of signal electrodes and a display element placed therebetween, said display control method comprising the steps of:

applying, in accordance with information to be displayed, a non-zero first driving selection signal to a selected one of the group of scanning electrodes during a first period, and applying a non-zero second driving selection signal to the selected scanning electrode in a second period after the first period, each of the first and second driving selection signals being applied to the selected scanning electrode for enabling a writing operation while data signals are being applied to the group of signal electrodes,

wherein the first and second periods both occur during a single horizontal scan period of a frame,

wherein polarities of portions of the first driving signal are opposite to polarities of corresponding portions of the second driving signal, and

wherein polarities of the first and second driving selection signals applied to a subsequent scanning electrode are inverted from polarities of the first and second driving selection signals, respectively, applied to at least one previous scanning electrode.

2. A display control device for controlling a display device having a group of scanning electrodes and a group of signal electrodes so positioned in a matrix form as to define a group of pixels, and a display element positioned between said group of scanning electrodes and said group of signal electrodes, said display control device comprising:

a signal generator for applying, in accordance with information to be displayed, a non-zero first driving selection signal to a selected one of the group of scanning electrodes during a first period, and for applying a non-zero second driving selection signal to the selected scanning electrode in a second period after the first period, each of the first and second driving signals being applied to the selected scanning electrode for enabling a writing operation while data signals are being applied to the group of signal electrodes,

wherein the first and second periods both occur during a single horizontal scan period of a frame,

wherein the first and second periods are separated by a zero-voltage rest period,

wherein polarities of portions of the first driving selection signal are opposite to polarities of corresponding portions of the second driving selection signal, and

wherein said signal generator inverts the polarities of the first and second driving selection signals after all the scanning electrodes in the group have been selected at least once.

3. A display apparatus comprising:

a display device provided with a group of scanning electrodes and a group of signal electrodes and a display element placed therebetween;

display control means for controlling said display device; and

a driving selection signal generator for applying, in accordance with information to be displayed, a non-zero first driving selection signal to a selected one of the group of scanning electrodes during a first period, and for applying a non-zero second driving selection signal to the selected scanning electrode in a second period after the first period, each of the first and second driving selection signals being applied to the selected scanning electrode for enabling a writing operation while data signals are being applied to the group of signal electrodes,

wherein the first and second periods both occur during a single horizontal scan period of a frame,

wherein polarities of portions of the first driving selection signal are opposite to polarities of corresponding portions of the second driving selection signal, and

wherein polarities of the driving selection signals applied to a subsequent scanning electrode are inverted from polarities of the first and second driving selection signals, respectively, applied to at least one previous scanning electrode.

4. A display control device for controlling a display device provided with a group of scanning electrodes and a group of signal electrodes and a display element placed therebetween, said display control device comprising:

a driving selection signal generator for applying, in accordance with information to be displayed, a non-zero first driving selection signal to a selected one of the group of scanning electrodes during a first period, and for applying a non-zero second driving selection signal to the selected scanning electrode in a second period after the first period, each of the first and second driving selection signals being applied to the selected scanning electrode for enabling a writing operation while data signals are being applied to the group of signal electrodes; and

a data supply means for supplying the information to be displayed,

wherein the first and second periods both occur during a single horizontal scan period of a frame,

wherein polarities of portions of the first driving selection signal are opposite to polarities of corresponding portions of the second driving selection signal, and

wherein polarities of the first and second driving selection signals applied to a subsequent scanning electrode are inverted from polarities of the first and second driving selection signals, respectively, applied to at least one previous scanning electrode.

5. A display control device according to claim 4, wherein the display element comprises a ferroelectric liquid crystal.

6. A display control device for controlling a display device provided with a group of scanning electrodes and a group of signal electrodes and a display element placed therebetween, said display control device comprising:

a driving selection signal generator for applying, in accordance with information to be displayed, a non-zero first driving selection signal to a selected one of the group of scanning electrodes during a first period, and for applying a non-zero second driving selection signal to the selected scanning electrode in a second period after the first period, each of the first and second driving selection signals being applied to the selected scanning electrode for enabling a writing operation while data signals are being applied to the group of signal electrodes,

wherein the first and second periods both occur during a single horizontal scan period of a frame,

wherein polarities of portions of the first driving selection signal are opposite to polarities of corresponding portions of the second driving selection signal,

wherein the first and second driving selection signals are separated by a zero-voltage rest period,

wherein the first driving selection signal comprises a bi-polar pulse, and wherein the second driving selection signal comprises a bi-polar pulse, and

wherein a first pulse of the bi-polar pulse of the first driving selection signal has a longer duration than that of a second pulse of the bi-polar pulse of the first driving selection signal, and wherein a first pulse of the bi-polar pulse of the second driving selection signal has a longer duration than that of a second pulse of the bi-polar pulse of the second driving selection signal.

7. A display control device according to claim 6, wherein polarities of the first and second driving selection signals applied to a subsequent scanning electrode are inverted from polarities of the first and second driving selection signals, respectively, applied to at least one previous scanning electrode.

8. A display control device according to claim 6, wherein the display element comprises a ferroelectric liquid crystal.

9. A display control device for controlling a display device provided with a group of scanning electrodes and a group of signal electrodes and a display element placed therebetween, said display control device comprising:

a driving selection signal generator for applying, in accordance with information to be displayed, a non-zero first driving selection signal to a selected one of the group of scanning electrodes during a first period, and for applying a non-zero second driving selection signal to the selected scanning electrode in a second period after the first period, each of the first and second driving selection signals being applied to the selected scanning electrode for enabling a writing operation while data signals are being applied to the group of signal electrodes,

wherein the first and second periods both occur during a single horizontal scan period of a frame,

wherein polarities of portions of the first driving selection signal are opposite to a polarities of corresponding portions of the second driving selection signal, and

wherein polarities of the first and second driving selection signals applied to a subsequent scanning electrode are inverted from polarities of the first and second driving selection signals, respectively, applied to at least one previous scanning electrode.

10. A display control device according to claim 9, wherein the display element comprises a ferroelectric liquid crystal.

11. A display control device according to claim 9, wherein the first driving selection signal comprises a bi-polar pulse, and wherein the second driving selection signal comprises a bi-polar pulse.

12. A display control device according to claim 9, wherein the first and second driving selection signals separated by a zero-voltage rest period.

13. A display control device according to claim 12, wherein the data signal includes a zero-voltage rest period which starts simultaneously with the zero-voltage rest period between the two driving selection signals.

14. A display control device according to claim 12, wherein a section of the first driving selection signal immediately before the zero-voltage rest period has the same polarity as a section of the second driving selection signal immediately after the zero-voltage rest period.

15. A display control device according to claim 12, wherein the first driving selection signal comprises a bi-polar pulse, and wherein the second driving selection signal comprises a bi-polar pulse.

16. A display control device according to claim 15, wherein a first pulse of the bi-polar pulse of the first driving selection signal has a longer duration than that of a second pulse of the bi-polar pulse of the first driving selection signal, and wherein a first pulse of the bi-polar pulse of the second driving selection signal has a longer duration than that of a second pulse of the bi-polar pulse of the second driving selection signal.

17. A display control device for controlling a display device having a group of scanning electrodes and a group of signal electrodes so positioned in a matrix form as to define a group of pixels, and a display element positioned between said group of scanning electrodes and said group of signal electrodes, said display control device comprising:

a signal generator for applying, in accordance with information to be displayed, a non-zero first driving selection signal to a selected one of the group of scanning electrodes during a first period, and for applying a non-zero second driving selection signal to the selected scanning electrode in a second period after the first period, each of the first and second driving signals being applied to the selected scanning electrode for enabling a writing operation while data signals are being applied to the group of signal electrodes,

wherein the first and second periods both occur during a single horizontal scan period of a frame,

wherein the first and second periods are separated by a zero-voltage rest period,

wherein polarities of portions of the first driving selection signal are opposite to polarities of corresponding portions of the second driving selection signal, and

wherein said signal generator inverts the polarities of the first and second driving selection signals applied to a subsequent scanning electrode from polarities of the first and second driving selection signals, respectively applied to at least one previous scanning electrode.

18. A display control device according to claim 17, wherein the display element comprises an optical modulating element having bistability characteristics when an electric field is applied.

19. A display control device according to claims 17 or 18, wherein the display element comprises a ferroelectric liquid crystal.

20. A display control device according to claim 17, wherein said signal generator inverts the polarity of the first and second driving selection signals during driving of the scanning electrodes.

21. A display control device according to claim 18, wherein said signal generator inverts the polarity of the first and second driving selection signals during driving of the scanning electrodes.

22. A display control device according to claim 19, wherein said signal generator inverts the polarity of the first and second driving selection signals during driving of the scanning electrodes.

23. A display control device according to claim 18, wherein said signal generator inverts the polarity of the driving selection signals after at least one scanning electrode has been selected.

24. A display control device according to claim 19, wherein said signal generator inverts the polarity of the driving selection signals applied to subsequent electrodes from a polarity of a driving selection signal applied to at least one previous scanning electrode.

25. A display control device according to claim 18, wherein said signal generator inverts the polarity of the driving selection signals after all the scanning electrodes in the group have been selected at least once.

26. A display control device according to claim 19, wherein said signal generator inverts the polarity of the driving selection signals after all the scanning electrodes in the group have been selected at least once.

27. A display control device according to claim 17, wherein the first driving selection signal comprises a bi-polar pulse, and wherein the second driving selection signal comprises a bi-polar pulse.

28. A display control device, for controlling a display device having a group of scanning electrodes and a group of signal electrodes, and a display element placed therebetween, said control device comprising:

a selecting signal generator for applying a non-zero first selecting signal to an n-th scanning electrode, when that electrode is selected from the group of scanning electrodes during a first frame, simultaneously with an application of a data signal to the group of signal electrodes, and for applying a non-zero second selecting signal to the n-th scanning electrode when that electrode is selected in a second frame after the first frame,

wherein the second selecting signal is applied to an (n+1)th scanning electrode during the first frame and the first driving signal is applied to the (n+1)th scanning electrode during the second frame,

wherein n is a predetermined positive integer,

wherein each of the selecting signals is a two-phase signal in which each phase is a selection signal for enabling a writing operation, and

wherein a a polarity of a portion of the first selecting signal before the rest period is opposite to a polarity of a corresponding portion of the second selecting signal after the rest period.

29. A display control device according to claim 28, wherein the display element comprises an optical modulating element having bistability characteristics when an electrical field is applied.

30. A display control device according to claims 28 or 29, wherein said optical modulating element comprises a ferroelectric liquid crystal element.

31. A display control device according to claim 28, wherein the first selecting signal comprises a bi-polar pulse, and wherein the second selecting signal comprises a bi-polar pulse.

32. A display control device according to claim 28, wherein the data signal comprises first and second portions separated by a zero-voltage rest period, and wherein the first and second selecting signals are separated by a zero-voltage rest period.

33. A display control device according to claim 32, wherein the zero-voltage rest period of the data signal and the zero-voltage rest period between the first and second selecting signals start simultaneously.

34. A display control device according to claim 32, wherein a section of the first selecting signal immediately before the zero-voltage rest period has the same polarity as a section of the second selecting signal immediately after the zero-voltage rest period.

35. A display control device according to claim 32, wherein the first selecting signal comprises a bi-polar pulse, and wherein the second selecting signal comprises a bi-polar pulse.

36. A display control device according to claim 35, wherein a first pulse of the bi-polar pulse of the first selecting signal has a longer duration than that of a second pulse of the bi-polar pulse of the first selecting signal, and wherein a first pulse of the bi-polar pulse of the second selecting signal has a longer duration than that of a second pulse of the bi-polar pulse of the second selecting signal.

37. A display control device for controlling a display device having a group of scanning electrodes and a group of signal electrodes so positioned in a matrix form as to define a group of pixels, and a display element positioned between said group of scanning electrodes and said group of signal electrodes, said display control device comprising:

a signal generator for applying, in accordance with information to be displayed, a non-zero first driving selection signal to a selected one of the group of scanning electrodes during a first period, and for applying a non-zero second driving selection signal to the selected scanning electrode in a second period after the first period, each of the first and second driving signals being applied to the selected scanning electrode for enabling a writing operation while data signals are being applied to the group of signal electrodes,

wherein the first and second periods both occur during a single horizontal scan period of a frame,

wherein the first and second periods are separated by a zero-voltage rest period,

wherein polarities of portions of the first driving selection signals are opposite to polarities of corresponding portions of the second driving selection signals, and

wherein the first and second driving selection signals are separated by a zero-voltage rest period.

38. A display control device according to claim 37, wherein the data signal includes a zero-voltage rest period which starts simultaneously with the zero-voltage rest period between the first and second driving selection signals.

39. A display control device according to claim 37, wherein a section of the first driving selection signal immediately before the zero-voltage rest period has the same polarity as a section of the second driving selection signal immediately after the zero-voltage rest period.

40. A display control device according to claim 37, wherein the first driving selection signal comprises a bi-polar pulse, and wherein the second driving selection signal comprises a bi-polar pulse.

41. A display control device according to claim 40, wherein a first pulse of the bi-polar pulse of the first driving selection signal has a longer duration than that of a second pulse of the bi-polar pulse of the first driving selection signal, and wherein a first pulse of the bi-polar pulse of the second driving selection signal has a longer duration than that of a second pulse of the bi-polar pulse of the second driving selection signal.

42. A display control device for controlling a display device provided with a group of scanning electrodes and a group of signal electrodes and a display element placed therebetween, said display control device comprising:

a scanning signal generator for applying a non-zero first scanning signal to a selected one of the group of scanning electrodes during a first period, and for applying a non-zero second scanning signal to the selected scanning electrode in a second period after the first period, each of the first and second scanning signals being applied to the selected scanning electrode for enabling a writing operation while a driving signal is being applied to a predetermined number of signal electrodes of the group of signal electrodes,

wherein the first and second periods both occur during a single horizontal scan period of a frame,

wherein the first and second periods are separated by a rest period,

wherein polarities of portions of the first scanning signal are opposite to polarities of corresponding portions of the second scanning signal, and

wherein polarities of the first and second scanning signals applied to a subsequent scanning electrode are inverted from polarities of the first and second scanning signals, respectively, applied to at least one previous scanning electrode.

43. A display control device according to claim 42, wherein the display element comprises an optical modulating element having bistability characteristics when an electric field is applied.

44. A display control device according to claim 42, wherein the display element comprises a ferroelectric liquid crystal.

45. A display control device according to claim 42, wherein said scanning signal generator inverts the polarities of the first and second scanning signals during driving of the scanning electrodes.

46. A display control device according to claim 42, wherein said scanning signal generator inverts the polarities of the first and second scanning signals applied to a subsequent scanning electrode from the respective polarities of the first and second scanning signals applied to at least one previous scanning electrode.

47. A display control device according to claim 42, wherein said scanning signal generator inverts the polarity of the scanning signals after all the scanning electrodes in the group have been selected at least once.

48. A display control device according to claim 43, wherein said scanning signal generator inverts the polarities of the first and second scanning signals during driving of the scanning electrodes.

49. A display control device according to claim 44, wherein said scanning signal generator inverts the polarity of the first and second scanning signals during driving of the scanning electrodes.

50. A display control device according to claim 43, wherein said scanning signal generator inverts the polarities of the first and second scanning signals after at least one scanning electrode has been selected.

51. A display control device according to claim 44, wherein said scanning signal generator inverts the polarities of the first and second scanning signals applied to subsequent electrodes from polarities of the first and second scanning signals, respectively, applied to at least one previous scanning electrode.

52. A display control device according to claim 43, wherein said scanning signal generator inverts the polarities of the first and second scanning signals after all the scanning electrodes in the group have been selected at least once.

53. A display control device according to claim 44, wherein said scanning signal generator inverts the polarities of the first and second scanning signals after all the scanning electrodes in the group have been selected at least once.