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

• US 6,304,239 B1
• Filed: 05/23/2000
• Issued: 10/16/2001
• Est. Priority Date: 12/19/1996
• Status: Expired due to Term

• Current Assignee: Emerson Radio Corporation (Nimble Holdings Co. Ltd.)
• Original Assignee: Zight Corporation (Three-Five Systems, Inc.)
• Inventors: McKnight, Douglas
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): NGUYEN, FRANCIS N
• Application Number:
  US09/576,759
• Time in Patent Office: 511 Days
• Field of Search: 345/87, 345/90, 345/94-96, 345/204, 345/205-206, 345/208-209, 349/33, 349/37
• 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 such that said first pixel data is substantially not displayed;

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 wherein said display system is capable of displaying said first pixel data and said second pixel data when a voltage across said electro-optic layer is substantially zero.

2. A method as in claim 1 wherein said step of 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 first image comprises a first color subframe and said second image comprises a second color subframe.

4. A method as in claim 2 wherein said electro-optic layer comprises a liquid crystal material and wherein said liquid crystal has at least a first light altering state and a second light altering state and wherein said first control voltage sets said liquid crystal in said first light altering state such that light cannot pass through said display system.

5. A method as in claim 4 wherein said second control voltage sets said liquid crystal in said second light altering state such that light is capable of passing through said display system.

6. A method as in claim 5 wherein said liquid crystal is a nematic liquid crystal.

7. A method as in claim 6 wherein said step of applying a first control voltage and said step of applying a second plurality of pixel data values overlap at least partially in time.

8. A method as in claim 7 wherein said step of applying a first control voltage and said step of applying a second plurality of pixel data values occur substantially contemporaneously in time.

9. A method as in claim 7 wherein said electrode is a common cover glass electrode which receives a DC balanced signal over time.

10. A method as in claim 7 wherein said step of applying a second plurality of pixel data values comprises storing said second plurality of pixel data values in a plurality of buffers.

11. A method as in claim 10 wherein each of said plurality of pixel electrode is disposed substantially over a corresponding buffer of said plurality of buffers.

12. A method as in claim 5 wherein said first control voltage is an AC (alternating current) voltage.

13. A method as in claim 5 wherein said first control voltage is approximately equal to one of a maximum voltage and a minimum voltage which can be applied to said plurality of pixel electrodes.

14. A method as in claim 5 wherein said first control voltage is approximately equal to one of a maximum voltage plus a first offset voltage and a minimum voltage minus a second offset voltage, wherein said maximum voltage and said minimum voltage are the maximum and minimum voltages which can be applied to said plurality of pixel electrodes.

15. A method as in claim 5 wherein said electrode is a compensating electrode disposed in said first substrate with said plurality of pixel electrodes.

16. A method as in claim 7 wherein said step of applying a first control voltage further comprises applying a third control voltage after said first control voltage and before said step of applying said second control voltage, wherein said third control voltage holds said light crystal in said first light altering state and said first control voltage rapidly places said light crystal in said first light altering state.

17. A method as in claim 10 wherein said second plurality of pixel data values is stored in said plurality of buffers on said first substrate while said first pixel data is displayed.

18. A method as in claim 5 further comprising:

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

19. A method as in claim 18 wherein said step of applying a first compensating voltage and said step of applying a first control voltage overlap at least partially in time.

20. A method as in claim 19 wherein said step of applying a first compensating voltage and said step of applying a first control voltage occur substantially contemporaneously in time.

21. 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 elecoptic 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 and then said display system displaying a second image represented by a second plurality of pixel data values after said electrode receives a second control voltage wherein said display system is capable of displaying said first image and said second image when a voltage across said electro-optic layer is substantially zero.

22. A display system as in claim 21 further comprising an electrode control driver coupled to said electrode to provide said first control voltage to said electrode.

23. A display system as in claim 22 wherein said electrode control driver provides said first control voltage in a phase controlled relationship relative to ending the display of said first image and provides said second control voltage in a phase controlled relationship relative to beginning the display of said second image.

24. A display system as in claim 23 wherein when said first control voltage is applied to said electrode, said first image cannot be substantially displayed even if said first plurality of pixel electrodes retain said fist plurality of pixel data values.

25. A display system as in claim 24 wherein upon said second control voltage being applied to said electrode, said second image is displayed such that substantially all of said first plurality of pixel electrodes cause a corresponding plurality of pixels in said second image to be simultaneously updated.

26. A display system as in claim 25 wherein said corresponding plurality of pixels include pixels on a plurality of rows of pixels of said display system.

27. A display system as in claim 26 wherein said first image comprises a first color subframe and said second image comprises a second color subframe.

28. A display system as in claim 26 wherein said second plurality of pixel data values is applied to said first plurality of pixel electrodes while applying said first control voltage to said electrode.

29. A display system as in claim 28 wherein said electro-optic layer comprises a liquid crystal material and wherein said liquid crystal has at least a first light altering state and a second light altering state and wherein said first control voltage sets said liquid crystal in said first light altering state such that light cannot pass through said display system and wherein said second control voltage sets said liquid crystal in said second light altering state such that light is capable of passing through said display system.

30. A display system as in claim 29 wherein said liquid crystal is a nematic liquid crystal.

31. A display system as in claim 29 wherein said electrode is a common cover glass electrode which receives a DC balanced signal over time.

32. A display system as in claim 29 wherein said first control voltage is an AC voltage.

33. A display system as in claim 23 further comprising a compensating electrode operatively coupled to said first plurality of pixel electrodes, said compensating electrode coupled to a compensating control driver to receive a compensating voltage during at least a portion of a time in which said first control voltage is applied to said first electrode.