Method and system for accentuating intense white display areas in sequential DMD video systems

• US 5,592,188 A
• Filed: 01/04/1995
• Issued: 01/07/1997
• Est. Priority Date: 01/04/1995
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Doherty, Donald B., Gove, Robert J.
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Stoll, Kara Farnandez
• Application Number:
  US08/368,448
• Time in Patent Office: 734 Days
• Field of Search: 345/32, 345/84, 345/85, 345/108, 345/147, 345/148, 345/150, 345/151, 348/270, 348/742, 348/743, 348/755, 348/756, 348/764, 348/770, 348/771, 359/224, 359/225, 359/230
• US Class Current: 345/84
• CPC Class Codes: G02B 26/008 in the form of devices for effecting sequential colour changes, e.g. colour wheels
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• 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: H04N 9/3114 by using a sequential colour filter producing one colour at a time

Abstract

A method and system for accentuating intense white display areas in sequential DMD video systems includes generating a special signal for each pixel that indicates whether to boost the intensity of that pixel in all colors. The method further includes enabling the mirrors to be turned on during times of color boundary of the color wheel such that DMD with mirrors receives different mixes of color light that are integrated together to produce intense white. The system may include degamma lookup tables for each color. The degamma lookup tables are augmented when the special signal is generated.

Claims

1. A method for accentuating intense white display areas in a sequential DMD video system comprising the steps of:

generating a special signal that indicates a boost white intensity; and

during the presence of said special signal, enabling a DMD mirror to be in the on position during times when a source of light for the DMD mirror traverses a color boundary of a color wheel.

2. A method for accentuating intense white display areas in a sequential DMD video system comprising the steps of:

generating a special signal for each pixel that indicates a boost white intensity of said pixel in all colors; and

during the presence of said special signal, enabling DMD mirrors of said DMD system to be turned on during the times a source of light traverses a color boundary of a color wheel such that said DMD mirrors receive different mixes of color light that are integrated together to produce the intense white.

3. The method of claim 2 including after the generating step the step of loading said special signals into a DMD array at the start of all color transition periods.

4. The method of claim 2 wherein said special signal is generated by first comparing red, green, and blue digital signals and generating the boost signal when the pixel from the red, green, and blue are all over a given threshold.

5. The method of claim 4 including the step of augmenting the original transfer function within the degamma lookup tables for the red, green, and blue colors in response to the generated special signal.

6. The method of claim 5 wherein the special signal is used to alter the gain in the degamma lookup tables to provide a smooth ramping function.

7. A system for accentuating intense white display areas in sequential DMD video system including a plurality of mirrors illuminated from a light source through a color wheel comprising:

a generator coupled to incoming color video signals for generating a special signal representing intensity above a given threshold; and

a mirror controller coupled to mirrors of said DMD video system and responsive to said special signal for enabling said mirrors to be turned on during traverses of color boundaries of said color wheel.

8. The system of claim 7, wherein said color video signals are red, green and blue video signals.

9. The system of claim 7 including separate degamma lookup tables coupled to each incoming color video signals for providing a first transfer function and said degramma lookup tables in response to said special signal augmenting said transfer function.

10. A system for accentuating intense white displays in split reset DMD video system including a plurality of DMD mirrors illuminated from a light source through a color wheel and wherein at color wheel boundaries stepped groups of pixels are sequentially turned off and in like order said stepped groups of pixels are sequentially turned on comprising, in combination:

a source of at least three color video signals;

a generator coupled to said color video signals for generating a special signal representing an intensity of all of said video signals above a given threshold; and

a mirror controller coupled to said DMD mirrors and responsive to said special signal for enabling said DMD mirrors to remain turned on during said color wheel boundaries.

11. The system of claim 10 including degamma lookup tables with one degamma table for each color, said lookup tables coupled to said generator and responsive to the generating of said special signal for boosting the transfer function of said tables.

12. A system for accentuating intense white displays in split reset DMD video system including a plurality of DMD mirrors illuminated from a light source through a color wheel and wherein at an absolute color wheel boundary time period all of said pixels are turned off and at first transition time period before said absolute color wheel boundary said pixels are sequentially turned off in groups before said absolute color boundary and at a second transition time period following said absolute color boundary in like order said stepped groups of pixels are sequentially turned on comprising, in combination:

a source of at least three color video signals;

a generator coupled to said color video signals for generating a special signal representing an intensity above a given threshold; and

a mirror controller coupled to said DMD mirrors and responsive to said special signal for enabling said DMD mirrors to be turned on during said absolute color boundaries and during said first and second transition time periods.

13. The system of claim 12 including degamma lookup tables with one for each color said lookup tables coupled to said generator and responsive to the generation of said special signal for boosting the transfer function of said tables.

14. A method for accentuating intense white displays in split reset DMD video system including a plurality of DMD mirrors illuminated from a light source through a color wheel and wherein at an absolute color wheel boundary time period all of said pixels are turned off and at first transition time period before said absolute color wheel boundary said pixels are sequentially turned off in groups before said absolute color boundary and at a second transition time period following said absolute color boundary in the same order said stepped groups of pixels are turned on comprising the steps of:

providing a source of at least three color video signals;

generating a special signal representing an intensity above a given threshold when all of said color video signals have about equal intensity above a given threshold; and

enabling said DMD mirrors to be turned on during said absolute color boundaries and during said first and second transition time periods in response to said special signal.

15. The method of claim 14 including the steps of:

providing degamma lookup tables for each color;

coupling said special signal to said tables, and augmenting the transfer function of said tables to produce a boost response in response to said special signal.

16. A method for accentuating intense white displays in split reset DMD video system including a plurality of DMD mirrors illuminated from a light source through a color wheel and wherein at color wheel boundaries stepped groups of pixels are sequentially turned off and in like order said stepped groups of pixels are turned on comprising the steps of:

providing a source of at least three color video signals;

generating a special signal representing an intensity of all of said video signals above a given threshold; and

enabling said DMD mirrors to remain turned on during said color wheel boundaries when said special signal is generated.

17. The method of claim 16 including the steps of:

providing degamma lookup tables for each color;

coupling said special signal to said tables and increasing the gain from said tables in response to said special signal.