Color display system with spatial light modulator(s) having color-to color variations for split reset

• US 5,657,036 A
• Filed: 04/26/1995
• Issued: 08/12/1997
• Est. Priority Date: 04/26/1995
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Gove, Robert J., Markandey, Vishal
• Primary Examiner(s): Powell, Mark R.
• Application Number:
  US08/429,388
• Time in Patent Office: 839 Days
• Field of Search: 345/85, 345/84, 345/89, 348/771
• US Class Current: 345/85
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• 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

Abstract

A method 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. The method can be used with a multiple spatial light modulators SLM system (20), which concurrently displays images of different colors, or with a single SLM system (10), which generates differently colored images sequentially during each frame period. For a multiple SLM system (20), the method is used with SLMs (14) that are memory-multiplexed, having "reset groups" that are loaded and displayed at different times. Corresponding rows of the SLM(s)s are associated with different reset groups.

Claims

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

corresponding each row of each said SLM with one row of each other said SLM, wherein said rows from each said SLMs have a same position on that SLM, thereby identifying corresponding rows;

connecting the rows of each said SLM in reset groups, such that each reset group is comprised of a number of rows of each said SLM, and such that corresponding SLM rows are not in the same reset group;

loading a first reset group with data having a certain bit-weight of said pixel data;

displaying said data loaded to said first reset group; and

repeating said loading step and said displaying step for each reset group and for each bit-weight of said pixel data, alternating among said reset groups.

2. The method of claim 1, wherein said repeating step is performed such that said bit-weights are loaded in different orders for different reset groups.

3. The method of claim 1, wherein said loading step and said displaying step are performed in two successive time slices of a frame period, said time slice being substantially determined by the display time for the data having the least significant bit weight.

4. The method of claim 1, wherein one said SLM displays data for two colors and one said SLM displays data for a third color.

5. The method of claim 1, wherein each said SLM displays data for a different color.

6. The method of claim 1, wherein said SLM is a digital micro-mirror device.

7. The method of claim 1, wherein said corresponding rows are along horizontal rows of said SLM and reset groups contain said horizontal rows.

8. The method of claim 1, wherein said corresponding rows are along diagonal rows of said SLM and said reset groups contain said diagonal rows.

9. A method of reducing artifacts in an image display system having a memory-multiplexed spatial light modulator (SLM), sequentially which displays images based on pixel data representing a different color via a color wheel:

assigning the rows of said SLM to reset groups, such that each reset group is comprised of a number of rows of said SLM;

loading a first reset group with data having a certain bit-weight of said pixel data;

displaying said data loaded to said first reset group;

repeating said loading step and said displaying step for each reset group and for each bit-weight of said pixel data of a first color, alternating among said reset groups; and

repeating said assigning, loading and displaying steps for said pixel data of a second color, such that said reset groups contain different rows of said SLM than those used for said first color.

10. The method of claim 9, wherein said repeating steps are performed such that said bit-weights are loaded in different orders for different reset groups.

11. The method of claim 9, wherein said loading step and said displaying step are performed in two successive time slices of a frame period, said time slice being substantially determined by the display time for the data having the least significant bit weight.

12. The method of claim 9, wherein said reset groups contain diagonal rows of said SLM.

13. The method of claim 9, wherein said reset groups contain horizontal rows of said SLM.

14. The method of claim 9, wherein said SLM is a digital micro-mirror device.