Variable luminosity display system

• US 5,287,096 A
• Filed: 09/18/1992
• Issued: 02/15/1994
• Est. Priority Date: 02/27/1989
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Thompson, E. Earle, DeMond, Thomas W.
• Primary Examiner(s): BRIER, JEFFERY A
• Application Number:
  US07/947,902
• Time in Patent Office: 515 Days
• Field of Search: 340/793, 340/767, 340/784, 340/763, 340/764, 340/783, 340/815.24, 340/815.27, 351/243, 358/60, 358/61, 358/62, 358/230, 358/236, 358/233, 350/269
• US Class Current: 345/697
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G09F 19/16 involving the use of mirrors
• CPC Class Codes: G09F 19/18 involving the use of optical projection means, e.g. projection of images on clouds projection apparatus per se G03B
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/066 Waveforms comprising a gently increasing or decreasing portion, e.g. ramp
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 3/2007 Display of intermediate tones
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2025 the sub-frames having all the same time duration
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• 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 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

A digitized video display system has a spatial light modulator which has individual elements which are controllable to produce individual beams which form an image. The individual elements are controllable at a frequency which is less than the critical flicker frequency of the human eye to produce individual beams which form an image. The individual elements are controlled to provide a luminosity control over individual pixels or voxels of the image.

Claims

1. A variable luminosity visual display system comprising:

(a) a light source for generating light along an optical path; and

(b) a spatial light modulator located in said optical path, said spatial light modulator including a plurality of elements, each said element individually and digitally controlled between a first transferring state and second non-transferring state and then between said second non-transferring state and said first transferring state for an associated portion of said light at an operating frequency equal to or higher than the critical flicker frequency of the human eye, wherein said associated portion of said light is controlled by the total amount of time said element resides in said first transferring state.

2. System as in claim 1 wherein said operating frequency varies partly dependent upon luminosity.

3. System as in claim 1 wherein said elements include mirror devices.

4. System as in claim 1 wherein said spatial light modulator includes light valves.

5. System as in claim 1 wherein said spatial modulator includes:

(a) an array of said elements;

(b) each said element having at least two different memory cells associated therewith, each said element selectively directly connected with one of said memory cells for control of said element cell;

(c) a first decoder for addressing said memory cells for storing information therein; and

(d) a second decoder operating independently of said first decoder for selecting which of said memory cells is directly connected for control.

6. System as in claim 5 wherein each memory cell includes at least two components.

7. System as in claim 6 wherein one component is a transistor.

8. System as in claim 6 where in one component stores capacitively.

9. System as in claim 6 wherein both components are transistors.

10. System as in claim 8 wherein one component stores capacitively.

11. System as in claim 5 wherein said memory cell is implemented in NMOS.

12. System as in claim 5 wherein said memory cell is implemented in PMOS.

13. System as in claim 5 wherein said second decoder simultaneously addresses one memory cell associated with substantially all of said display cells to display an image.

14. System as in claim 5 wherein said second decoder simultaneously addresses one memory cell associated with all of said display cells to display an image.

15. System as in claim 5 wherein said first decoder addresses a row of said array at a time.

16. A method of displaying an image comprising the steps of:

(a) generating light along an optical path; and

(b) controlling elements individually and digitally between a first transferring state and second non-transferring state, and then between said second state and said first state for an associated portion of said light at an operating frequency equal to or higher than the critical flicker frequency of the human eye, wherein said associated portion of said light is controlled by the total amount of time said element resides in said first transferring state.

17. Method as in claim 16 includes the step of varying said operating frequency partly dependent upon luminosity.

18. Method as in claim 16 wherein said step of controlling includes actuating deformable mirror devices.

19. Method as in claim 16 wherein said step of controlling includes actuating light valves.

20. A variable luminosity visual display system comprising:

(a) a light source for generating light in an optical path;

(b) a spatial light modulator located in said optical path, said spatial light modulator having a plurality of indivicually controllable elements;

(c) each of said elements having a first state for allowing an associated portion of said light to impinge on a remote surface and a second state for preventing said associated portion of said light from impinging on said remote surface with each element selectably controllable between said first and second states a plurality of times at a frequency equal to or greater than the critical flicker frequency of the human eye, wherein the perceived intensity is controlled by the total amount of time said element resides in said first transferring state.

21. System as in claim 20 includes the step of varying said operating frequency partly dependent upon luminosity.