Divided reset for addressing spatial light modulator

• US 6,201,521 B1
• Filed: 09/27/1996
• Issued: 03/13/2001
• Est. Priority Date: 09/29/1995
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Doherty, Donald B.
• Primary Examiner(s): Nguyen, Chanh
• Application Number:
  US08/721,862
• Time in Patent Office: 1,628 Days
• Field of Search: 345/84, 345/85, 345/100, 345/94, 345/98, 345/99, 345/56, 345/48, 345/87, 345/103, 348/770, 348/771, 348/806, 348/755
• US Class Current: 345/84
• CPC Class Codes: G09G 2310/0218 with collection of electrodes in groups for n-dimensional addressing
• CPC Class Codes: G09G 2310/061 for resetting or blanking
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833

Abstract

A method of implementing pulse-width modulation in a display system (10, 20) that uses a spatial light modulator (SLM) (15). Each frame of data is divided into bit-planes, each bit-plane having one bit of data for each display element of the SLM and representing a bit weight of the intensity value to be displayed by the display elements. Each bit-plane has a display time corresponding to a portion of the frame period, with bit-planes of more significant bits having longer portions. The SLM is divided into reset groups connected to different reset lines (34), so that one reset group can be loaded and its display time begun while the next reset group is loaded. (FIG. 3). Short bit-planes are possible because the display time need not include the time to load the entire array, and for any reset group, its reset can be delayed while other reset groups are loaded.

Claims

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

loading a first portion of a bit plane of image data into said memory cells corresponding with a first reset group of said micromirror elements;

resetting said first reset group of said micromirror elements; and

loading a second portion of a bit plane of image data into said memory cells corresponding with a second reset group of said micromirror elements during said resetting step.

2. The method of claim 1, said array of micromirror elements comprising an orthogonal array of elements arranged in rows and columns of elements such that each reset group is comprised a plurality of said rows of elements, each of said rows of elements in a given reset group contiguous to other said rows of elements in said given reset group.

3. The method of claim 1, said array of micromirror elements comprising an orthogonal array of elements arranged in rows and columns of elements such that each reset group is comprised a plurality of said rows of elements, each of said rows of elements in a given reset group interleaved with rows of elements in other reset groups.