Systems and methods of actuating MEMS display elements

• US 20060250350A1
• Filed: 04/14/2006
• Published: 11/09/2006
• Est. Priority Date: 05/05/2005
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Cummings, William J., Kothari, Manish
• Granted Patent: US 7,948,457 B2
• Time in Patent Office: Days
• US Class Current: 345/108
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/0254 Control of polarity reversal in general, other than for liquid crystal displays
• 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 3/3466 based on interferometric effect

Abstract

Methods of writing display data to MEMS display elements are configured to minimize charge buildup and differential aging. Prior to writing rows of image data, a pre-write operation is performed. The pre-write operation with either actuate or release substantially all pixels in a row prior to writing the image data. In some embodiments, the selection between actuating or releasing is performed in a random or pseudo-random manner.

Claims

1. A method of writing a plurality of rows of image data to a display array, said display array comprising pixels that exhibit two different states, a first state and a second state, said method comprising:

for a first portion of said plurality of rows, placing substantially all of said pixels in said first state prior to writing image data;

for a second, different portion of said plurality of rows, placing substantially all of said pixels in said second state prior to writing image data.

2. The method of claim 1, wherein writing each row of image data to said array is preceded by either placing substantially all of said pixels in said first state or placing substantially all of said pixels in a second state.

3. The method of claim 1, wherein said first and second portions together comprise all rows of said array.

4. The method of claim 1, wherein said first portion comprises approximately half of said rows of said array and said second portion comprises approximately the other half of said rows of said array.

5. The method of claim 4, comprising alternating between placing substantially all of said pixels in said first state and placing substantially all of said pixels in said second state.

6. The method of claim 1, comprising selecting between placing substantially all said pixels in said first state and placing substantially all of said pixels in said second state in a random or pseudo-random manner.

7. The method of claim 1, wherein said first state comprises a released state and wherein said second state comprises an actuated state.

8. The method of claim 1, wherein each pixel of said array is subjected to a series of voltages having either a first or a second polarity.

9. The method of claim 8, wherein each pixel of said array is subjected to a substantially equal number of voltages of each of said first and second polarities over a given time frame.

10. The method of claim 8, wherein each pixel of said array is subjected to a pre-defined unequal number of voltages of each of said first and second polarities over a given time frame.

13. The display apparatus of claim 11, further comprising:

a processor that is in electrical communication with said display, said processor being configured to process image data;

a memory device in electrical communication with said processor.

14. The apparatus of claim 13, further comprising:

a controller configured to send at least a portion of said image data to said driver circuit.

15. The apparatus of claim 13, further comprising:

an image source module configured to send said image data to said processor.

16. The apparatus of claim 15, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

17. The apparatus of claim 13, further comprising:

an input device configured to receive input data and to communicate said input data to said processor.

11. A display apparatus comprising:

a display array comprising display elements that exhibit two different states;

a driver circuit configured to write rows of image data to at least one row of said display array;

wherein said driver circuit is further configured to select from a set of at least two pre-write operations to be performed prior to writing a row of image data to said row, wherein a first of said pre-write operations places substantially all of said display elements in said row into a first state, and wherein a second of said pre-write operations places substantially all of said display elements into a second state.

12. The display apparatus of claim 11, wherein said driver circuit is configured to select from said pre-write operations in a random or pseudo-random manner.

18. A display apparatus comprising:

means for displaying image data on an array of pixels;

means for writing rows of image data to at least one row of said displaying means; and

means for selecting from a set of at least two pre-write operations to be performed prior to writing a row of image data to said row, wherein a first of said pre-write operations places substantially all of said display elements in said row into a first state, and wherein a second of said pre-write operations places substantially all of said display elements into a second state.

19. The display apparatus of claim 18, wherein said means for displaying comprises an array of interferometric modulators.

20. The display apparatus of claim 18, wherein said means for writing and said means for selecting comprise driver circuitry.