Color display system with spatial light modulator(s) having color-to-color variations in data sequencing

• US 5,777,589 A
• Filed: 04/26/1995
• Issued: 07/07/1998
• Est. Priority Date: 04/26/1995
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Gale, Richard O., Markandey, Vishal, Deffner, Gerhard P.
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Flynn, Nathan J.
• Application Number:
  US08/429,387
• Time in Patent Office: 1,168 Days
• Field of Search: 348/739, 348/742, 348/744, 348/750, 348/751, 348/752, 348/753, 348/754, 348/755, 348/756, 348/757, 348/758, 348/759-775, 348/795
• US Class Current: 345/84
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0266 Reduction of sub-frame artefacts
• 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
• CPC Class Codes: G09G 5/399 using two or more bit-mapped memories, the operations of which are switched in time, e.g. ping-pong buffers
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/31 Projection devices for colour picture display , e.g. using electronic spatial light modulators [ESLM]
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

Methods of reducing artifacts in SLM-based display systems (10, 20), whose images are based on data displayed by bit-weight for pulse-width modulated intensity levels. A first method is suitable for systems (20) that use multiple SLMs (14) to concurrently display images of different colors, which are combined at the image plane. The data for each color are staggered in time (FIG. 4). A second method is suitable for either multiple SLM systems (20) or for systems (10) that use a single SLM (14) and a color wheel (17) to display differently colored images sequentially. The data for each color is arranged in a different data sequence (FIG. 5). In either method, the intensity transitions do not occur at the same time.

Claims

1. A method of reducing artifacts in an image display system having multiple spatial light modulators (SLMs), each SLM displaying images based on data representing a different color, comprising the steps of:

determining a display sequence for data of each color, wherein said display sequence represents the order of display of different bit-weights during each frame period;

delivering said data of each color to a corresponding SLM; and

displaying said data of each color such that each said display sequence begins at a time that is slightly offset from each other said display sequence.

2. The method of claim 1, wherein said displaying step is accomplished by offsetting each said display sequence by one or more time slices.

3. The method of claim 1, further comprising the step of providing a control signal so that said displaying step is performed in response to said control signal.

4. The method of claim 3, wherein said control signal is generated by a motion detection process.

5. The method of claim 3, wherein said control signal is generated by a picture quality detection process.

6. The method of claim 3, wherein each said display sequence has sequences for split reset groups of pixel elements of said SLM.