Spatial and temporal pulse width modulation method for image display

• US 9,230,296 B2
• Filed: 02/28/2013
• Issued: 01/05/2016
• Est. Priority Date: 02/28/2012
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Clatanoff, Todd Alan, King, Philip Scott, Kempf, Jeffrey Mathew
• Primary Examiner(s): Koziol, Stephen R
• Assistant Examiner(s): HICKEY, DIANA S
• Application Number:
  US13/781,300
• Publication Number:
  US 20130222403A1
• Time in Patent Office: 1,041 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G06T 1/60 Memory management

Abstract

A method of controlling micromirrors of reset groups of a spatial light modulator (SLM) digital micromirror array is disclosed. In a first reset operation, the positions of a first subgroup of micromirrors of a reset group are set based on a first portion of a first bitplane and the positions of a second subgroup of micromirrors of the same reset group are set based on a first portion of a second bitplane. Then, in a second reset operation, the positions of the first subgroup are set based on a second portion of the second bitplane and the positions of the second subgroup are set based on a second portion of a first bitplane. In one example, subsets of alternating rows of micromirrors of the same reset group are successively set according to alternating data corresponding to different ones of first and second bitplanes.

Claims

1. A method of controlling a micromirror array, the array comprised of an array of individually controllable micromirror elements arranged in a plurality of reset groups, each of the micromirror elements in a given reset group having a one-to-one correspondence with a respective memory cell of an array of memory cells, the method comprising the steps of:

loading a first portion of a first bit plane of image data into a first subset of memory cells corresponding to a first subset of micromirror elements of the given reset group;

loading a first portion of a second bit plane of image data into a second subset of memory cells corresponding to a second subset of micromirror elements of the given reset group;

resetting the micromirror elements of the given reset group in a first reset operation, to set positions of the first subset of micromirror elements based on the first portion of the first bit plane loaded into the first subset of memory cells, and to set positions of the second subset of micromirror elements based on the first portion of the second bit plane loaded into the second subset of memory cells;

loading a second portion of the second bit plane of image data into the first subset of memory cells;

loading a second portion of the first bit plane of image data into the second subset of memory cells; and

resetting the micromirror elements of the given reset group in a second reset operation, to set positions of the first subset of micromirror elements based on the second portion of the second bit plane loaded into the first subset of memory cells, and to set positions of the second subset of micromirror elements based on the second portion of the first bit plane loaded into the second subset of memory cells.

2. The method of claim 1, the array of micromirror elements in each reset group being arranged in rows and columns of micromirror elements;

the first subset of micromirror elements comprising micromirrors of a subset of rows or columns of the given reset group; and

the second subset of micromirror elements comprising micromirrors of a subset of different rows or columns of the given reset group.

3. The method of claim 2, wherein the rows or columns of the subset of different rows or columns comprise rows or columns interleaved with the rows or columns of the subset of rows or columns.

4. The method of claim 3, wherein the rows or columns of the subset of rows or columns comprise rows;

and wherein the rows or columns of the subset of different rows or columns comprise rows alternating with the rows of the subset of rows or columns.

5. A method of controlling a micromirror array, the array comprised of an array of individually controllable micromirror elements arranged in a plurality of reset groups, each of the micromirror elements in a given reset group having a one-to-one correspondence with a respective memory cell of an array of memory cells, the method comprising the steps of:

loading a first portion of a first bit plane of image data into a first subset of memory cells corresponding to a first subset of micromirror elements of the given reset group;

loading a first portion of a second bit plane of image data into a second subset of memory cells corresponding to a second subset of micromirror elements of the given reset group;

resetting the micromirror elements of the given reset group in a first reset operation, to set positions of the first subset of micromirror elements based on the first portion of the first bit plane loaded into the first subset of memory cells, and to set positions of the second subset of micromirror elements based on the first portion of the second bit plane loaded into the second subset of memory cells;

with the first portion of the first bit plane of image data remaining in the first subset of memory cells, loading a first portion of a third bit plane of image data into the second subset of memory cells;

resetting the micromirror elements of the given reset group in a second reset operation, to retain positions of the first subset of micromirror elements based on the first portion of the first bit plane loaded into the first subset of memory cells, and to set positions of the second subset of micromirror elements based on the first portion of the third bit plane loaded into the second subset of memory cells;

with the first portion of the third bit plane of image data remaining in the second subset of memory cells, loading a first portion of a fourth bit plane of image data into the first subset of memory cells; and

resetting the micromirror elements of the given reset group in a second reset operation, to set positions of the first subset of micromirror elements based on the first portion of the fourth bit plane loaded into the first subset of memory cells, and to retain positions of the second subset of micromirror elements based on the first portion of the third bit plane loaded into the second subset of memory cells.