Display system having electrode modulation to alter a state of an electro-optic layer

• US 6,078,303 A
• Filed: 02/18/1997
• Issued: 06/20/2000
• Est. Priority Date: 12/19/1996
• Status: Expired due to Term

• Current Assignee: Emerson Radio Corporation (Nimble Holdings Co. Ltd.)
• Original Assignee: Colorado Microdisplay Inc.
• Inventors: McKnight, Douglas
• Primary Examiner(s): Hjerpe, Richard A.
• Assistant Examiner(s): NGUYEN, FRANCIS N
• Application Number:
  US08/801,994
• Time in Patent Office: 1,218 Days
• Field of Search: 345/94, 345/95, 345/90, 345/87, 345/96, 345/204, 345/205, 345/208, 345/209
• US Class Current: 345/87
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0823 used to establish symmetry in driving, e.g. with polarity inversion
• 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 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 2310/063 Waveforms for resetting the whole screen at once
• CPC Class Codes: G09G 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• 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 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

Methods and apparatuses for display systems which modulate a control electrode to cause an electro-optic layer to be reset to a state in which display data is not viewable. In one embodiment of the invention, a display system includes a first substrate having a first plurality of pixel electrodes for receiving a first plurality of pixel data values representing a first image to be displayed. The display system further includes an electro-optic layer which is operatively coupled to the pixel electrodes and an electrode operatively coupled to the electro-optic layer. The display system displays the first image and then applies a first control voltage to the electrode to alter a state of the electro-optic layer such that the first image substantially not displayed and then the display system displays a second image represented by a second plurality of pixel data values after the electrode receives a second control voltage. Various other apparatuses and methods are described.

Claims

1. A method for operating a display system, said display system comprising a first substrate having a plurality of pixel electrodes, an electro-optic layer operatively coupled to said pixel electrodes and an electrode operatively coupled to said electro-optic layer, said method comprising:

applying a first plurality of pixel data values to said plurality of pixel electrodes such that a first pixel data represented by said first plurality of pixel data values is displayed;

applying a first control voltage to said electrode to alter a state of said electro-optic layer after applying said first plurality of pixel data values to said plurality of pixel electrodes such that said first pixel data is substantially not displayed;

applying a second plurality of pixel data values to said plurality of pixel electrodes while applying said first control voltage to said electrode, said second plurality of pixel data values representing a second pixel data;

displaying said second pixel data.

2. A method as in claim 1 wherein said displaying said second pixel data comprises:

applying a second control voltage to said electrode to alter said state of said electro-optic layer such that said second pixel data is displayed, and

wherein a first image is represented by said first pixel data and a second image is represented by said second pixel data.

3. A method as in claim 2 wherein said electro-optic layer comprises a liquid crystal and said display system is a reflective liquid crystal light modulator disposed on a semiconductor substrate and said electrode is a common cover glass electrode.

4. A method as in claim 2 wherein after applying said second control voltage, said electro-optic layer relaxes to a plurality of gray scale or color levels corresponding to said second plurality of pixel data values.

5. A method as in claim 1 wherein said display system displays a plurality of display frames and wherein said applying a first plurality of pixel data values and said applying a first control voltage are repeated for each of said display frames.

6. A method as in claim 1 wherein said displaying said second pixel data comprises illuminating said display system with at least one first pulse of illumination which does not provide continuous illumination during said displaying of said second pixel data.

7. A method as in claim 1 Wherein during said displaying said second pixel data, said electro-optic layer relaxes to a plurality of gray scale or color levels corresponding to said second plurality of pixel data values.

8. A method as in claim 1 further comprising:

applying a first compensating voltage to a plurality of compensating electrodes disposed on said first substrate.

9. A method as in claim 1 wherein said first pixel data comprises a first color subframe and said second pixel data comprises a second color subframe and wherein said display system displays images using time sequential color subframes.

10. A method as in claim 9 wherein said first substrate comprises a plurality of pixel circuits each of which corresponds to a pixel electrode of said plurality of pixel electrodes and wherein each of said pixel circuits comprises only one transistor which is coupled to a corresponding one of said pixel electrodes.

11. A method for operating a display system, said display system comprising a first substrate having a plurality of pixel electrodes, an electro-optic layer operatively coupled to said pixel electrodes and an electrode operatively coupled to said electro-optic layer, said method comprising:

applying a first plurality of pixel data values to said plurality of pixel electrodes such that a first pixel data represented by said first plurality of pixel data values is displayed;

applying a first control voltage to said electrode to alter a state of said electro-optic layer after applying said first plurality of pixel data values to said plurality of pixel electrodes such that said first pixel data is substantially not displayed wherein for at least a set of pixels of said first pixel data, said electro-optic layer has not reached a saturated display level for said first pixel data when said first control voltage is applied;

applying a second plurality of pixel data values to said plurality of pixel electrodes, said second plurality of pixel data values representing a second pixel data;

displaying said second pixel data.

12. A method as in claim 11 wherein said displaying said second pixel data comprises:

applying a second control voltage to said electrode to alter said state of said electro-optic layer such that said second pixel data is displayed, and

wherein a first image is represented by said first pixel data and a second image is represented by said second pixel data and wherein said step of applying a first control voltage and said step of applying a second plurality of pixel data values occur substantially contemporaneously.

13. A method as in claim 12 wherein said electro-optic layer comprises a liquid crystal and said display system is a reflective liquid crystal light modulator disposed on a semiconductor substrate and said electrode is a common cover glass electrode.

14. A display system comprising:

a first substrate having a first plurality of pixel electrodes for receiving a first plurality of pixel data values representing a first image to be displayed;

an electro-optic layer operatively coupled to said pixel electrodes;

an electrode operatively coupled to said electro-optic layer, said display system displaying said first image and then applying a first control voltage to said electrode to alter a state of said electro-optic layer such that said first image is substantially not displayed while loading a second plurality of pixel data values onto said first plurality of pixel electrodes and then said display system displaying a second image represented by said second plurality of pixel data values after said electrode receives a second control voltage.

15. A display system as in claim 14 wherein said electro-optic layer comprises a liquid crystal and said electrode comprises a cover glass electrode.

16. A display system as in claim 15 wherein for at least a set of pixels of said first image, said electro-optic layer has not reached a saturated display level for said set of pixels when said first control voltage is applied to said electrode.

17. A display system as in claim 15 further comprising at least one compensating electrode in said first substrate, said compensating electrode receiving a first compensating voltage.

18. A display system as in claim 14 wherein said display system displays a plurality of display frames and wherein said first plurality of pixel electrodes receive said first plurality of pixel data values once for each of said display frames and wherein said first control voltage is applied to said electrode once for each of said display frames.

19. A display system as in claim 14 further comprising:

an illuminator optically coupled to said electro-optic layer, said illuminator providing at least one first pulse of illumination which does not provide continuous illumination when said display system displays said first image, and said illuminator providing at least one second pulse of illumination which does not provide continuous illumination when said display system displays said second image.

20. A method for operating a display system, said display system comprising a first substrate having a plurality of pixel electrodes capable of displaying pixel data values, an electro-optic layer operatively coupled to said pixel electrodes and an electrode operatively coupled to said electro-optic layer, said method comprising:

applying a first control voltage to said electrode to alter said electro-optic layer such that no pixel data values are displayed by said plurality of pixel electrodes disposed along at least two rows of said display system;

applying a plurality of first pixel data values to said plurality of pixel electrodes while applying said first control voltage;

applying a second control voltage to said electrode to display said plurality of first pixel data values by said plurality of pixel electrodes disposed along said at least two rows;

applying, after applying said second control voltage, a third control voltage to said electrode to alter said electro-optic layer such that no pixel data values are displayed by said plurality of pixel electrodes disposed along said at least two rows;

applying a plurality of second pixel data values to said plurality of pixel electrodes while applying said third control voltage;

applying a fourth control voltage to said electrode to display said plurality of second pixel data values by said plurality of pixel electrodes disposed along said at least two rows.

21. A method as in claim 20 wherein said first control voltage and said third control voltage are either substantially equal or one is substantially an inverse, with respect to a voltage level, of the other.

22. A method as in claim 20 wherein said second control voltage and said fourth control voltage are either substantially equal or one is substantially an inverse, with respect to a voltage level, of the other.

23. A method as in claim 20 wherein said plurality of first pixel data values are substantially not displayed while applying said first control voltage even after said first pixel data values have been applied to said plurality of pixel electrodes.

24. A method as in claim 23 wherein said plurality of second pixel data values are substantially not displayed while applying said third control voltage even after said second pixel data values have been applied to said plurality of pixel electrodes.