Display methods and apparatus

• US 20060250325A1
• Filed: 01/06/2006
• Published: 11/09/2006
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Barton, Roger, Lewis, Stephen, Hagood, Nesbitt W., McAllister, Abraham
• Granted Patent: US 9,158,106 B2
• Time in Patent Office: Days
• US Class Current: 345/55
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/04 by periodically varying the intensity of light, e.g. using choppers shutters, diaphragms for cameras G03B9/00; devices for eliminating or reducing the effect of flicker in projection systems G03B21/40
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/088 using a non-linear two-terminal element
• CPC Class Codes: G09G 2310/02 Addressing, scanning or driving the display screen or processing steps related thereto
• CPC Class Codes: G09G 2310/0218 with collection of electrodes in groups for n-dimensional addressing
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• 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 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2310/063 Waveforms for resetting the whole screen at once
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38

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 display apparatus comprising:

an array of pixels including

a substrate having a plurality of apertures, and

a plurality of shutters corresponding to the plurality of apertures,

wherein a pixel in the array of pixels includes at least one aperture of the plurality of apertures and its corresponding shutter from the plurality of shutters; and

a control matrix connected to the substrate including, for the pixel, a switch, a shutter-open electrode and a shutter-close electrode for selectively moving the corresponding shutter transverse to the substrate to modulate light directed towards the pixel to form an image.

2. The display apparatus of claim 1, wherein the switch comprises a transistor.

3. The display apparatus of claim 1, wherein the switch comprises a diode.

4. The display apparatus of claim 1, wherein the switch comprises a varistor.

5. The display apparatus of claim 1, wherein the switch is configured to regulate an electric potential applied to the shutter-open electrode.

6. The display apparatus of claim 1, wherein the switch is configured to regulate an electric potential applied to the shutter-close electrode.

7. The display apparatus of claim 5, wherein the control matrix comprises, for the pixel, a second switch configured to regulate an electric potential applied to the shutter-close electrode.

8. The display apparatus of claim 1, wherein the control matrix comprises, for the pixel, a shutter-open interconnect, a shutter-close interconnect, a write-enable interconnect, and an actuation voltage interconnect.

9. The display apparatus of claim 8, wherein the write-enable interconnect for receiving a write-enabling voltage.

10. The display apparatus of claim 8, wherein the pixel comprises a first capacitor corresponding to the shutter-open interconnect and second capacitor corresponding to the shutter-close interconnect.

11. The display apparatus of claim 8, wherein the pixel comprises a first resistor corresponding to the shutter-open interconnect and second resistor corresponding to the shutter-close interconnect.

12. The display apparatus of claim 10, wherein the switch is electrically connected to the shutter-open interconnect, the first capacitor, and the actuation voltage line, and for the pixel, the control matrix comprises a second switch in electrical communication with the shutter-close interconnect, the second capacitor, and the actuation voltage interconnect.

13. The display apparatus of claim 12, wherein, in response to the application of a voltage to the switch by the shutter-open interconnect, the switch facilitates discharging the first capacitor, thereby actuating the corresponding shutter.

14. The display apparatus of claim 12, wherein, in response to the application of a voltage to the second switch by the shutter-close interconnect, the second switch facilitates discharging the second capacitor, thereby actuating the corresponding shutter.

15. The display apparatus of claim 1, wherein the control matrix comprises a global actuation circuit for initiating substantially simultaneous actuation of a plurality of the plurality of shutters.

16. The display apparatus of claim 12, wherein, in response to the application of a voltage to the switch by the shutter-open interconnect, the switch facilitates charging the first capacitor, thereby actuating the corresponding shutter.

17. The display apparatus of claim 12, wherein, in response to the application of a voltage to the second switch by the shutter-close interconnect, the second switch facilitates charging the second capacitor, thereby actuating the corresponding shutter.

18. The display apparatus of claim 8, comprising an actuation voltage source electrically connected to the actuation voltage interconnect and a data voltage source electrically connected to at least one of the shutter-open interconnect and the shutter-close interconnect, wherein the actuation voltage source outputs a voltage with a higher magnitude than is output by the data voltage source.

19. The display apparatus of claim 18, wherein the actuation voltage source outputs a voltage having a magnitude at least about 5 times greater than is output by the data voltage source.

20. The display apparatus of claim 8, wherein:

a plurality of pixels in the array of pixels are arranged in a scan line, and the pixels in the scan line share a common write-enable interconnect.

21. The display apparatus of claim 8, wherein the pixels in the array of pixels are arranged in columns of pixels and the pixels in a particular one of the columns of pixels share at least one of a common shutter-open interconnect and a shutter-close interconnect.

22. The display apparatus of claim 1, wherein the pixel includes a memory element for storing a shutter movement instruction.

23. The display apparatus of claim 22, wherein the memory element comprises a capacitor.

24. The display apparatus of claim 22, wherein the memory element comprises one of a SRAM circuit and a DRAM circuit.

25. The display apparatus of claim 22, wherein application of a write enabling voltage to the write-enabling interconnect prepares the memory element to store the shutter movement instruction.

26. The display apparatus of claim 25, wherein the matrix comprises a global actuation interconnect for initiating the substantially simultaneous execution of shutter movement instructions stored in memory elements of a plurality of pixels in the array of pixels.

27. A display apparatus, comprising:

an array of pixels including

a substrate having a plurality of apertures, and

a plurality of shutters corresponding to respective ones of the plurality of apertures, wherein a shutter has at least one mechanical support substantially limiting a range of motion of the shutter to a movement plane that is parallel to a plane defined by the substrate,

wherein a pixel in the array of pixels includes at least one aperture of the plurality of apertures and its respective shutter of the plurality of shutters; and

a control matrix, connected to the substrate, for modulating light directed towards the substrate to form an image, wherein, for the pixel, the control matrix includes,

a shutter-open electrode,

a shutter-close electrode, and

a switch for selectively controlling the application of a voltage to one of the shutter-open electrode and the shutter-close electrode to generate an electrical field between the shutter corresponding to the pixel and the one of the shutter-open electrode and the shutter-close electrode, thereby electrostatically driving the corresponding shutter substantially within the movement plane transverse to the substrate.

40. The method of claim 27, wherein selecting the first scan line comprises applying a write-enabling voltage to a write-enable interconnect shared among the pixels in the scan line.

28. A method of forming an image on a display, comprising:

selecting a scan-line of the display, wherein the scan line includes a plurality of pixels;

for at least one of the plurality of pixels in the selected scan line, selectively regulating a voltage across one of a shutter-open actuator and a shutter-close actuator, thereby enabling one of the shutter-open actuator and the shutter-close actuator to move a corresponding shutter transversely adjacent an aperture defined in a substrate;

directing light towards the plurality of pixels to form an image.

29. The method of claim 28, wherein regulating the voltage comprises charging a capacitor.

30. The method of claim 28, wherein regulating the voltage comprises discharging a capacitor.

31. The method of claim 28, wherein regulating the voltage comprises applying a first electric potential with a first magnitude to a switch to regulate the application of a second electric potential with a substantially greater magnitude to the one of the shutter-open actuator and the shutter-close actuator, wherein the magnitude of the second potential is sufficiently large to actuate the one of the shutter-open actuator and the shutter-close actuator.

32. The method of claim 28, wherein regulating the voltage comprises storing a shutter movement instruction on a memory element corresponding to the pixel.

33. The method of claim 32, wherein the memory element comprises a capacitor.

34. The method of claim 32, wherein the memory element comprises one of a SRAM circuit and a DRAM circuit.

35. The method of claim 28, wherein enabling the one of the shutter-open actuator and the shutter-close actuator to move the corresponding shutter comprises actuating the one of the shutter open actuator and the shutter close actuator.

36. The method of claim 28, wherein enabling the one of the shutter-open actuator and the shutter-close actuator to move the corresponding shutter comprises substantially reducing an additional minimum voltage change needed to actuate the one of the shutter-actuator and the shutter-close actuator.

37. The method of claim 36, comprising applying a global actuation voltage to the plurality of pixels to provide the additional minimum voltage change to actuate the pixels.

38. The method of claim 30 comprising deselecting the selected scan line and recharging the discharged capacitor.

39. The method of claim 38, comprising:

selecting a second series of pixels arranged in a second scan line, the second series of pixels having corresponding shutter-open energy stores and shutter-close energy stores;

for at least one of the pixels in the second scan line, enabling one of a second shutter-open actuator and a second shutter-close actuator to move a corresponding second shutter transversely adjacent to a second aperture in the substrate.; and

applying a global actuation voltage, thereby initiating, substantially simultaneously, the transverse movement of the corresponding shutter and the second corresponding shutter.