CIRCUITS FOR CONTROLLING DISPLAY APPARATUS

• US 20120280971A1
• Filed: 07/17/2012
• Published: 11/08/2012
• Est. Priority Date: 02/23/2005
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Hagood, Nesbitt W., Lewis, Stephen, McAllister, Abraham, Barton, Roger W., Payne, Richard S., Steyn, Jasper Lodewyk
• Application Number:
  US13/551,025
• Publication Number:
  US 20120280971A1
• Time in Patent Office: Days
• US Class Current: 345/212
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• 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 2300/0876 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 2360/18 Use of a frame buffer in a display terminal, inclusive of the display panel
• 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
• CPC Class Codes: G09G 3/3473 based on light coupled out of a light guide, e.g. due to scattering, by contracting the light guide with external means

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:

a substrate;

an array of pixels, wherein each pixel includes;

at least one actuator; and

at least one MEMS device capable of modulating light, wherein each of the MEMS devices can be driven to at least three states, including;

a substantially open state, a substantially closed state, and a partially open state; and

a control matrix for driving each of the MEMS devices in the array of pixels into one of the at least three states.

2. The display apparatus of claim 1, wherein the control matrix drives a MEMS device into the substantially open state by applying an actuation voltage across the at least one actuator.

3. The display apparatus of claim 2, wherein the control matrix drives a MEMS device into the substantially closed state by applying an actuation voltage across the at least one actuator.

4. The display apparatus of claim 3, wherein the control matrix drives a MEMS device into the partially open state by applying an intermediate voltage across the at least one actuator.

5. The display apparatus of claim 4, wherein the intermediate voltage is between a ground voltage and the actuation voltage.

6. The display apparatus of claim 3, wherein the at least one actuator comprises opposing first and second actuators.

7. The display apparatus of claim 6, wherein the control matrix drives a MEMS device into the partially open state by applying a pair of complementary voltages that, when applied simultaneously across the opposing first and second actuators, results in controlled states of partial opening.

8. The display apparatus of claim 1, wherein the control matrix includes:

a plurality of scan-line interconnects running in a first direction, each enabling a plurality of pixels along the first direction to respond to data voltages; and

a plurality of data interconnects running in a second direction perpendicular to the first direction, each providing data voltages to a plurality of pixels along the second direction.

9. The display apparatus of claim 1, wherein the substrate is transparent.

10. The display apparatus of claim 1, wherein the MEMS device modulates light by moving transversely through a path of a propagating ray of light.

11. The display apparatus of claim 1, further comprising a restoring spring opposing the at least one actuator.

12. The display apparatus of claim 1, wherein the control matrix includes:

an actuation voltage interconnect for applying an actuation voltage to the at least one actuator;

a grayscale switch electrically connected between the actuation voltage interconnect and the at least one actuator; and

a data voltage interconnect coupled to the grayscale switch, wherein a data voltage on the data voltage interconnect controls the grayscale switch.

13. The display apparatus of claim 12, wherein the actuation voltage applied to the at least one actuator varies in proportion to the data voltage resulting in an incremental displacement of the MEMS device.

14. The display apparatus of claim 13, wherein the controller drives a MEMS device into one of the at least three states based at least in part on the magnitude of the data voltage applied to the data voltage interconnect.

15. The display apparatus of claim 14, wherein the controller drives a MEMS device into one of the at least three states based at least in part on the duration of the data voltage applied to the data voltage interconnect.

16. The display apparatus of claim 12, further comprising a data store capacitor electrically coupled to the data voltage interconnect for storing the data voltage corresponding to the one of at least three states of the MEMS device.

17. A method for displaying an image frame, comprising:

applying a write-enabling voltage to a scan-line interconnect in a first row of an array of MEMS devices;

applying a data voltage to at least one data-interconnect for a first MEMS device in the first row of the array; and

actuating the first MEMS device to drive the first MEMS device into the one of at least three states;

a substantially open state, a substantially closed state, and a partially open state.

18. The method of claim 17, wherein the partially open state includes a range of partially open states between the substantially open state and the substantially closed state.

19. The method of claim 18, wherein the range of partially open states includes discrete ranges of partial MEMS device opening.

20. The method of claim 17, wherein displacement of the MEMS device is proportional to the data voltage.

21. The method of claim 17, wherein the data voltage comprises an analog data voltage.