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

• US 6,104,367 A
• Filed: 08/27/1997
• Issued: 08/15/2000
• 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): Tran, Henry N.
• Application Number:
  US08/920,602
• Time in Patent Office: 1,084 Days
• Field of Search: 345/87, 345/88, 345/90, 345/93, 345/95, 345/98, 345/99, 345/50, 345/51, 345/84, 345/113, 345/115, 345/150, 345/151, 345/205-208, 345/94, 345/103, 345/210
• US Class Current: 345/94
• 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, a control device coupled to at least one of 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 is 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. The control device applies a first reference voltage to the at least one pixel electrode before the display system displays the second image. Various other apparatuses and methods are described.

Claims

1. A display system comprising:

a first substrate having a first plurality of pixel electrodes disposed in a plurality of rows, 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 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;

a control device coupled to said first plurality of said pixel electrodes, said control device applying a first reference voltage to said pixel electrodes before said display system displays said second image.

2. A display system as in claim 1 wherein said control device comprises a multiplexer.

3. A display system as in claim 1 wherein said first reference voltage is applied to said first plurality of said pixel electrodes during at least a portion of a time that said first image is substantially not displayed.

4. A display system as in claim 1 further comprising:

a first row electrode coupled to a first row of said pixel electrodes, said first row of pixel electrodes being a subset of said first plurality of pixel electrodes;

a plurality of column drivers, each of which is coupled to a respective pixel electrode of said first row of pixel electrodes, and wherein said control device is coupled to at least one of said column drivers.

5. A display system as in claim 4 wherein said electro-optic layer comprises a liquid crystal material and wherein said control device is coupled to each of said plurality of column drivers.

6. A display system as in claim 5 wherein said first reference voltage is applied to each pixel electrode of said first row of pixel electrodes during at least a portion of a time that said first image is substantially not displayed.

7. A display system as in claim 6 wherein said first image comprises a first color subframe and said second image comprises a second color subframe.

8. A display system as in claim 6 wherein said second plurality of pixel data values is applied to said first plurality of pixel electrodes after said first reference voltage is applied to said first plurality of pixel electrodes.

9. A display system as in claim 8 wherein said control device allows said plurality of column drivers to apply said second plurality of pixel data values to said first plurality of pixel electrodes after said first reference voltage is applied to said first plurality of pixel electrodes.

10. A display system as in claim 9 wherein said electrode provides a third control voltage after said first control voltage and before said applying said second control voltage, wherein said third control voltage holds said electro-optic layer in a first light altering state and said first control voltage rapidly places said electro-optic layer in said first light-altering state, and wherein said control device allows said plurality of column drivers to apply said second plurality of pixel data values to said first plurality of pixel electrodes while said third control voltage holds said electro-optic layer in said first light altering state.

11. A display system comprising:

a first substrate having a first plurality of pixel electrodes, disposed in a first plurality of rows, for receiving a first plurality of pixel data values representing a first portion of an image and having a second plurality of pixel electrodes, disposed in a second plurality of rows, for receiving a second plurality of pixel data values representing a second portion of said image;

an electro-optic layer having a first portion of said electro-optic layer operatively coupled to said first plurality of pixel electrodes and having a second portion of said electro-optic;

layer operatively coupled to said second plurality of pixel electrodes;

a first electrode coupled to a first electrode control driver and operatively coupled to said first portion of said electro-optic layer, said first electrode receiving a first control voltage to alter a state of said first portion of said electro-optic layer such that said first portion of said image is substantially not displayed;

a second electrode coupled to a second electrode control driver and operatively coupled to said second portion of said electro-optic layer, said second electrode receiving a second control voltage to alter a state of said second portion of said electro-optic layer such that said second portion of said image is substantially not displayed;

a first control device coupled to said first plurality of pixel electrodes, said first control device applying a first reference voltage to said first plurality of pixel electrodes during at least a portion of time when said first portion of said image is substantially not displayed;

a second control device coupled to said second plurality of pixel electrodes, said second control device applying said first reference voltage to said second plurality of pixel electrodes during at least a portion of time when said second portion of said image is substantially not displayed.

12. A display system as in claim 11 wherein a first electrode is a first portion of a cover glass and said second electrode is a second portion of said cover glass.

13. A display system as in claim 12 wherein said first plurality of pixel electrodes are coupled to a first plurality of row electrodes and said second plurality of pixel electrodes are coupled to a second plurality of row electrodes and said first control device is coupled to said first plurality of row electrodes and said second control device is coupled to said second plurality of row electrodes.

14. A display system as in claim 13 wherein said electro-optic layer comprises a liquid crystal material and wherein said liquid crystal material has at least a first light altering state and a second light altering state and wherein said first and said second control voltages set said liquid crystal material in said first light altering state such that light cannot pass through said display system and said first electrode control driver and said second electrode control driver respectively provide a third control voltage and a fourth control voltage which set said liquid crystal in said second light altering state such that light is capable of passing through said display system.

15. A method for operating a display system, said display system comprising a first substrate having a plurality of pixel electrodes disposed along a plurality of rows, an electro-optic layer operatively coupled to said pixel electrodes, a control device coupled to said plurality of 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 first reference voltage to said plurality of pixel electrodes;

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; and

displaying said second pixel data, wherein said first reference voltage is applied to said plurality of pixel electrodes before applying said second plurality of pixel data values.

16. A method as in claim 15 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.

17. A method as in claim 16 wherein said first image comprises a first color subframe and said second image comprises a second color subframe.

18. A method as in claim 16 wherein said electro-optic layer comprises a liquid crystal material and wherein said liquid crystal material has at least a first light altering state and a second light altering state and wherein said first control voltage sets said liquid crystal material in said first light altering state such that light cannot pass through said display system.

19. A method as in claim 18 wherein said second control voltage sets said liquid crystal material in said second light altering state such that light is capable of passing through said display system.

20. A method as in claim 16 further comprising:

applying a third control voltage to said electrode after applying said first control voltage and before said applying said second control voltage, wherein said third control voltage holds said electro-optic layer in a first light altering state and said first control voltage rapidly places said electro-optic layer in said first light altering state.

21. A method for operating a display system, said display system comprising a first substrate having a first plurality of pixel electrodes coupled to a first control device, said first plurality of pixel electrodes being disposed in a first plurality of rows, and a second plurality of pixel electrodes coupled to a second control device said second plurality of pixel electrodes being disposed in a second plurality of rows, an electro-optic layer operatively coupled to said first and said second plurality of pixel electrodes, and a first electrode and a second electrode, said method comprising:

applying a first plurality of pixel data values to said first plurality of pixel electrodes, said first plurality of pixel data values representing a first portion of an image;

applying a first control voltage to said first electrode to alter a state of a first portion of said electro-optic layer such that said first portion of said image is not displayed;

applying a first reference voltage to said first plurality of pixel electrodes after applying said first control voltage;

displaying said first portion of said image after applying said first reference voltage;

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

applying a second control voltage to said second electrode to alter a state of a second portion of said electro-optic layer such that said second portion of said image is not displayed;

applying said first reference voltage to said second plurality of pixel electrodes after applying said second control voltage; and

displaying said second portion of said image after applying said first reference voltage.

22. A method as in claim 21 wherein said first electrode is a first portion of a cover glass electrode disposed on a second substrate and said second electrode is a second portion of said cover glass electrode, said first portion and said second portion of said cover glass electrode not being electrically coupled.

23. 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;

a nematic liquid crystal (LC) layer operatively coupled to said pixel electrodes;

an electrode operatively coupled to said nematic LC layer, said display system displaying said first image and then applying a first control voltage to said electrode to alter a state of said nematic LC 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;

a control device coupled to at least one of said pixel electrodes, said control device applying a first reference voltage to at least one of said pixel electrodes before said display system displays said second image.

24. A display system as in claim 23 wherein said control device is coupled to said first plurality of pixel electrodes and applies said first reference voltage to said first plurality of pixel electrodes which are disposed along at least two rows.

25. A display system as in claim 23 wherein said control device comprises a multiplexer.

26. A display system as in claim 23 wherein said first reference voltage is applied to said one of said pixel electrodes during at least a portion of a time that said first image is substantially not displayed.

27. A display system as in claim 23 further comprising:

a first row electrode coupled to a first row of pixel electrodes, said first row of pixel electrodes being a subset of said first plurality of pixel electrodes;

a plurality of column drivers, each of which is coupled to a respective pixel electrode of said first row of pixel electrodes, and wherein said control device is coupled to at least one of said column drivers.

28. A display system as in claim 23 wherein said electrode provides a third control voltage after said first control voltage and before said applying said second control voltage, wherein said third control voltage holds said nematic LC layer in a first light altering state and said first control voltage rapidly places said nematic LC layer in said first light-altering state, and wherein said control device allows said plurality of column drivers to apply said second plurality of pixel data values to said first plurality of pixel electrodes while said third control voltage holds said electro-optic layer in said first light altering state.

29. A method for operating a display system, said display system comprising a first substrate having a plurality of pixel electrodes disposed along a plurality of rows, an electro-optic layer operatively coupled to said pixel electrodes, a control device coupled to substantially all of 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 first reference voltage to substantially all of said pixel electrodes;

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 wherein said first reference voltage is applied after said first control voltage is applied and before said second plurality of pixel data values is applied; and

displaying said second pixel data.

30. If A method as in claim 29 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.

31. A method as in claim 30 wherein said first image comprises a first color subframe and said second image comprises a second color subframe.

32. A method as in claim 30 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.

33. A method as in claim 32 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.

34. A method as in claim 30 further comprising:

applying a third control voltage to said electrode after applying said first control voltage and before said applying said second control voltage, wherein said third control voltage holds said electro-optic layer in a first light altering state and said first control voltage rapidly places said electro-optic layer in said first light altering state.