Circuits for controlling display apparatus

• US 8,519,945 B2
• Filed: 10/29/2007
• Issued: 08/27/2013
• Est. Priority Date: 01/06/2006
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Hagood, Nesbitt W., Lewis, Stephen R., McAllister, Abraham, Barton, Roger W.
• Primary Examiner(s): PHAM, VIET DAVID
• Application Number:
  US11/978,829
• Publication Number:
  US 20080129681A1
• Time in Patent Office: 2,129 Days
• Field of Search: 345/84, 345/204, 345/108, 359/290
• US Class Current: 345/109
• CPC Class Codes: G09G 2300/0838 with level shifting
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 2300/0871 with level shifting
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: G09G 5/001 Arbitration of resources in a display system, e.g. control of access to frame buffer by video controller and/or main processor

Abstract

The invention relates to methods and apparatus for forming images on a display utilizing a control matrix to control the movement of MEMs-based light modulators.

Claims

1. A direct view display apparatus comprising:

a transparent substrate;

an array of pixels formed on the substrate including, for each pixel, a MEMS-based light modulator including a first movable electrostatic actuator; and

a control matrix connected to the substrate including, for a pixel, a write-enabling interconnect for enabling the pixel to respond to a data voltage and a data voltage interconnect for applying the data voltage to a data switch, thereby controlling the state of the light modulator of the pixel; and

a voltage regulator that limits variation in a voltage across the first movable electrostatic actuator, wherein the variation in the voltage is caused by a movement of at least a portion of the first movable electrostatic actuator.

2. The direct-view display apparatus of claim 1, wherein the voltage regulator comprises a display driver including a DC voltage source.

3. The direct-view display apparatus of claim 2, comprising for a pixel, an actuation voltage interconnect, distinct from the data voltage interconnect, for connecting the first movable electrostatic actuator to the direct-view display driver.

4. The direct-view display apparatus of claim 3, comprising, for a pixel, a switch, other than the data switch, for controlling the application of the voltage output by the direct-view display driver to the first movable electrostatic actuator.

5. The direct-view display apparatus of claim 1, wherein each pixel includes a voltage regulator.

6. The direct-view display apparatus of claim 5, wherein the voltage regulator comprises a capacitor in electrical communication with the first electrostatic actuator.

7. The direct-view display apparatus of claim 1, wherein the voltage variation is limited if, during actuation, movement of portions of the first movable electrostatic actuator results in a voltage reduction of less than twenty percent of a voltage level required to initiate actuation.

8. The direct-view display apparatus of claim 1, wherein the voltage variation is limited if, during actuation, movement of portions of the first movable electrostatic actuator results in a voltage reduction of less than ten percent of a voltage level required to initiate actuation.

9. The direct-view display apparatus of claim 1, wherein the voltage variation is limited if, during actuation, movement of portions of the first movable electrostatic actuator results in a voltage reduction of less than five percent of a voltage level required to initiate actuation.

10. The direct-view display apparatus of claim 1, comprising a voltage inverter.

11. The direct-view display apparatus of claim 10, wherein the voltage inverter comprises a CMOS circuit.

12. The direct-view display apparatus of claim 1, wherein each light modulator comprises a second electrostatic actuator for applying a force opposing a force applied by the first actuator.

13. The direct-view display apparatus of claim 12, comprising, for a pixel, a flip-flop electrically coupling the first movable electrostatic actuator and the second electrostatic actuator.

14. The direct-view display apparatus of claim 12, comprising, for a pixel, a cross-coupled inverter electrically coupling the first movable electrostatic actuator and the second electrostatic actuator.

15. The direct-view display apparatus of claim 1, wherein the MEMS-based light modulators comprise shutter-based light modulators.

16. The direct-view display apparatus of claim 1, comprising a second electrostatic actuator, opposing the first movable electrostatic actuator, for controlling the state of the MEMS-based light modulators.

17. The direct-view display apparatus of claim 16, comprising, for a pixel, a first actuation voltage interconnect for providing a voltage to the first movable electrostatic actuator sufficient to actuate the first movable electrostatic actuator.

18. The direct-view display apparatus of claim 17, wherein the first actuation voltage interconnect provides a substantially constant voltage throughout the setting of an image and through the setting of subsequent images.

19. The direct-view display apparatus of claim 17, wherein, throughout operation of the direct-view display, the first actuation voltage interconnect provides a substantially constant voltage.

20. The direct-view display apparatus of claim 17, wherein first actuation voltage interconnect for a pixel is shared by a plurality of pixels.

21. The direct-view display apparatus of claim 17, comprising, for a pixel, a second voltage actuation interconnect, distinct from the data voltage interconnect and the first voltage actuation interconnect, for providing a voltage sufficient to actuate the second actuator.

22. The direct-view display apparatus of claim 21, wherein the voltage provided by the second actuation voltage interconnect is insufficient to actuate the second actuator if a voltage greater than a maintenance voltage is applied to the first actuator.

23. The direct-view display apparatus of claim 21, comprising, for a pixel, a switch, other than the data switch, for regulating the application of the voltage provided via the first actuation voltage interconnect.

24. The direct-view display apparatus of claim 21, wherein the data voltage interconnect for the pixel controls the actuation of both the first and second actuators.

25. The direct-view display apparatus of claim 21, comprising a common voltage interconnect coupled to the light modulators of a plurality of pixels for applying a common bias voltage to the light modulators.

26. The direct-view display apparatus of claim 21, wherein the data switch comprises a discharge transistor for selectively discharging the voltage provided via the first voltage actuation interconnect.

27. The direct-view display apparatus of claim 26, comprising a global actuation interconnect coupled to the discharge transistors of a plurality of pixels for selectively enabling the voltage provided to the respective pixels via the data voltage interconnects corresponding to the pixels to control the discharge transistor.

28. The direct-view display apparatus of claim 1, comprising a voltage actuation interconnect electrically connected directly to the first movable electrostatic actuators of pixels in multiple rows and multiple columns of the array of pixels.

29. A display apparatus comprising:

a transparent substrate;

an array of pixels including for each pixel, a MEMS-based light modulator formed on the transparent substrate; and

a control matrix formed on the transparent substrate for addressing the MEMS-based light modulators of the array, wherein for each pixel, the control matrix includes a CMOS circuit comprising a level shifting inverter for controlling an actuation voltage with a data voltage, wherein the data voltage is less than the actuation voltage.

30. The display apparatus of claim 29, wherein the CMOS circuit comprises a flip-flop.

31. The display apparatus of claim 30, wherein the flip-flop controls the application of an actuation voltage to the light modulator.

32. The display apparatus of claim 30, wherein the flip-flop electrically couples opposing actuators of the light modulator.

33. The display apparatus of claim 29, wherein the MEMS-based light modulator comprises at least one of a shutter-based light modulator, a light tap-based light modulator, and an electrowetting-based light modulator.

34. The direct-view display apparatus of claim 29, wherein the MEMS-based light modulator comprises a light tap-based light modulator.

35. The direct-view display apparatus of claim 29, wherein the MEMS-based light modulator comprises an electrowetting-based light modulator.