Optical system for projection display using spatial light modulator device

• US 4,680,579 A
• Filed: 09/08/1983
• Issued: 07/14/1987
• Est. Priority Date: 09/08/1983
• Status: Expired due to Fees

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Ott, Granville E.
• Primary Examiner(s): Brigance, Gerald L.
• Assistant Examiner(s): Brier, Jeffery A.
• Application Number:
  US06/530,327
• Time in Patent Office: 1,405 Days
• Field of Search: 350/171, 350/487, 350/607, 350/611, 350/608, 350/360, 350/1.1, 350/1.6, 350/600, 350/601, 350/642, 358/62, 358/233, 358/234, 358/89, 340/702, 340/795, 340/806, 340/810, 340/752, 340/783
• US Class Current: 348/755
• CPC Class Codes: G02B 26/06 for controlling the phase of light G02B26/08 takes precedence , measuring optical phase difference G01J9/00
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/3105 for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators simultaneous projection in colour photography G03B33/10; beam splitting or combining systems per se G02B27/10
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

The projection display of the present invention employs a light source, a spatial light modulator such as a deformable mirror device having a plurality of individually electrically deformable mirror cells and Schlierin optics to project light from deformed mirror cells onto a viewing screen. An optical system forms light from the light source into a substantially collinear beam. A Schlierin optical device composed of alternating reflecting and transmitting portions is disposed at an angle to this beam. Light reflected or transmitted by the Schlierin optical device is focused by additional optics to a point near the deformable mirror device. Light reflected from undeformed mirror cells passes through the Schlierin optical device back to the light source. Deformed mirror cells reflect light at least in part to differing portions of the Schlierin optical device to follow a different path to a viewing screen. Control of the deformation of individual mirror cells thus enables control of illumination of corresponding spots on the viewing screen. A color picture may be formed using multiple deformable mirror devices and color filters. A three-dimensional image may be formed using multiple projection systems and a directionally reflecting screen or polarizing filters for differing deformable mirror devices with matching polarizing glasses.

Claims

1. An electronic display device comprising:

a light source;

a first optical system for forming a substantially collinear beam of light from said light source;

a Schlierin optical device having alternating reflecting and transmitting portions for forming respective reflecting and transmitting optical paths, said Schlierin optical device disposed to receive light from said first optical system at an angle;

a second optical system disposed to receive light from one of said reflecting or transmitting optical paths of said Schlierin optical device for focusing light received from said Schlierin optical device to a focal point;

a deformable mirror device disposed near said focal point for receiving light from said source optical system, said deformable mirror device having a matrix of a plurality of individually electrically deformable mirror cells, each mirror cell normally reflecting light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to similar type portions and being electrically deformable to reflect at least some light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to another type of said reflecting and transmitting portions of said Schlierin optical device;

a nonreciprocal optical device disposed between said light source and said Schlierin optical device for transmitting more light from said light source to said Schlierin optical device than reflected back to said light source and for reflecting more light back to said Schlierin optical device than transmitted from said Schlierin optical device to said light source; and

a viewing screen disposed for receiving light reflected by deformed mirror cells of said deformable mirror device.

2. An electronic display device comprising:

a light source;

a first optical system for forming a substantially collinear beam of light from said light source;

a Schlierin optical device having alternating reflecting and transmitting portions for forming respective reflecting and transmitting optical paths, said Schlierin optical device disposed to receive light from said first optical system at an angle;

a second optical system disposed to receive light from one of said reflecting or transmitting optical paths of said Schlierin optical device for focusing light received from said Schlierin optical device to a first focal point;

a first deformable mirror device disposed near said first focal point for receiving light from said second optical system, said first deformable mirror device having a matrix of a plurality of individually electrically deformable mirror cells, each mirror cell normally reflecting light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to similar type portions and being electrically deformable to reflect at least some light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to another type of said reflecting and transmitting portions of said Schlierin optical device;

a third optical system disposed to receive light from the other of said reflecting or transmitting optical paths of said Schlierin optical device as compared to said one of said reflecting or transmitting optical paths of said Schlierin optical device disposed to be received by said second optical system for focusing light received from said Schlierin optical device to a second focal point;

a second deformable mirror device disposed near said second focal point for receiving light from said third optical system, said second deformable mirror device having a matrix of a plurality of individually electrically deformable mirror cells, each mirror cell normally reflecting light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to similar type portions and being electrically deformable to reflect at least some light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to another type of said reflecting and transmitting portions of said Schlierin optical device; and

a viewing screen disposed for receiving light reflected by deformed mirror cells of said first and second deformable mirror devices.

3. An electronic display device as claimed in claim 2, further comprising:

a first filter disposed between said Schlierin optical device and said first deformable mirror device; and

a second filter different from said first filter disposed between said Schlierin optical device and said second deformable mirror device.

4. An electronic display device as claimed in claim 3, wherein:

one of said first or second filters is the primary color green and the other of said first or second filters has alternate portions of the primary color red and the primary color blue.

5. An electronic display device as claimed in claim 4, further comprising:

a third filter disposed between said Schlierin optical device and said first deformable mirror device for transmitting only light polarized in a first direction; and

a fourth filter disposed between said Schlierin optical device and said second deformable mirror device for transmitting only light polarized in a second direction orthogonal to said first direction.

6. An electronic display device as claimed in claim 5, further comprising:

a fifth filter disposed between said viewing screen and a first one of an observer'"'"'s eyes for transmitting only light polarized in said first direction; and

a sixth filter disposed between said viewing screen and a second one of an observer'"'"'s eyes for transmitting only light polarized in said second direction.

7. An electronic display device as claimed in claim 3, wherein:

said first filter is a polarizing filter for transmitting only light polarized in a first direction; and

said second filter is a polarizing filter for transmitting only light polarized in a second direction orthogonal to said first direction.

8. An electronic display device as claimed in claim 7, further comprising:

a third filter disposed between said viewing screen and a first one of an observer'"'"'s eyes for transmitting only light polarized in said first direction; and

a fourth filter disposed between said viewing screen and the other one of an observer'"'"'s eyes for transmitting only light polarized in said second direction.

9. An electronic display device as claimed in claim 2, wherein:

said first deformable mirror device and said second deformable mirror device are aligned whereby individual mirror cells are disposed in a first direction in said first deformable mirror device and control the illumination of a first set of alternating spots on said viewing screen and individual mirror cells disposed in said first direction in said second deformable mirror device control the illumination of a second set of alternating spots disposed in said first direction on said viewing screen.

10. An electronic display device as claimed in claim 9, wherein:

said Schlierin optical device comprises alternating stripes of reflecting portions and transmitting portions, said stripes disposed in said first direction.

11. An electronic display device comprising:

a light source;

a first optical system for forming a substantially collinear beam of light from said light source;

a Schlierin optical device having alternating reflecting and transmitting portions for forming respective reflecting and transmitting optical paths, said Schlierin optical device disposed to receive light from said first optical system at an angle;

a second optical system disposed to receive light from one of said reflecting or transmitting optical paths of said Schlierin optical device for focusing light received from said Schlierin optical device to a first focal point;

a first deformable mirror device disposed near said first focal point for receiving light from said second optical system, said first deformable mirror device having a matrix of a plurality of individually electrically deformable mirror cells, each mirror cell normally reflecting light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to similar type portions and being electrically deformable to reflect at least some light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to another type of said reflecting and transmitting portions of said Schlierin optical device;

an optical beam splitting device disposed to receive light from the other of said reflecting or transmitting optical paths of said Schlierin optical device for splitting said light into first and second optical paths;

a third optical system disposed to receive light from said first optical path of said optical beam splitting device for focusing light received from said optical beam splitting device to a second focal point;

a second deformable mirror device disposed near said second focal point for receiving light from said third optical system, said second deformable mirror device having a matrix of a plurality of individually electrically deformable mirror cells, each mirror cell normally reflecting light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to similar type portions and being electrically deformable to reflect at least some of the light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to another type of said reflecting and transmitting portions of said Schlierin optical device;

a fourth optical system disposed to receive light from said second optical path of said optical beam splitting device for focusing light received from said optical beam splitting device to a third focal point;

a third deformable mirror device disposed near said third focal point for receiving light from said fourth optical system, said third deformable mirror device having a matrix of a plurality of individually electrically deformable mirror cells, each mirror cell normally reflecting light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to similar type portions and being electrically deformable to reflect at least some light received from one type of said reflecting and transmitting portions of said Schlierin optical device back to another type of said reflecting and transmitting portions of said Schlierin optical device; and

a viewing screen disposed for receiving light reflected by deformed mirror cells of said first, second and third deformable mirror devices.

12. An electronic display system as claimed in claim 11, further comprising:

a first color filter disposed between said Schlierin optical device and said first deformable mirror device;

a second color filter disposed between said optical beam splitting device and said second deformable mirror device; and

a third color filter disposed between said optical beam spltting device and said third deformable mirror device.

13. An electronic display device as claimed in claim 12, wherein:

a first one of said first, second and third color filters is the primary color green, a second one of said first, second and third color filters is the primary color red and a third one of said first, second and third color filters is the primary color blue.

14. An electronic display system comprising:

a first projection system including;

(1) a first light source, (2) a first spatial light modulating means disposed to receive light from said first light source, said first spatial light modulating means having a plurality of individually electrically controllable modulator cells for modulating light received from said first light source, and (3) a first viewing means for spatially localizing light modulated by said first spatial light modulating means to a first one of an observer'"'"'s eyes;

said first viewing means comprises a first viewing screen disposed to be visible only to said first one of the observer'"'"'s eyes for receiving light modulated by said first spatial light modulating means; and

a second projection system including;

(1) a second light source;

(2) a second spatial light modulating means disposed to receive light from said second light source, said second spatial light modulating means having a plurality of individually electrically controllable modulator cells for modulating light received from said second light source, and (3) a second viewing means for spatially localizing light modulated by said second spatial light modulating means to a second one of an observer'"'"'s eyes;

said second viewing means comprises a second viewing screen disposed to be visible only to said second one of the observer'"'"'s eyes for receiving light modulated by said second spatial light modulating means.

15. An electronic display system comprising:

a first projection system including;

(1) a first light source, (2) a first spatial light modulating means disposed to receive light from said first light source, said first spatial light modulating means having a plurality of individually electrically controllable modulator cells for codulating light received from said first light source, and (3) a first viewing means for spatially localizing light modulated by said first spatial light modulating means to a first one of an observer'"'"'s eyes;

a second projection system including;

(1) a second light source, (2) a second spatial light modulating means disposed to receive light from said second light source, said second spatial light modulating means having a plurality of individually electrically controllable modulator cells for modulating light received from said second light source, and (3) a second viewing means for spatially localizing light modulated by said second spatial light modulating means to a second one of an observer'"'"'s eyes;

a viewing screen visible to both said first and second ones of the observer'"'"'s eyes;

said first viewing means comprises a first filter disposed between said first light source and said viewing screen for transmitting only light polarized in a first direction and a second filter disposed between said viewing screen and said first one of the observer'"'"'s eyes for transmitting only light polarized in said first direction; and

said second viewing means comprises a third filter disposed between said second light source and said viewing screen for transmitting only light polarized in a second direction orthogonal to said first direction and a fourth filter disposed between said viewing screen and said second one of the observer'"'"'s eyes for transmitting only light polarized in said second direction.

16. An electronic display system comprising:

a first projection system including;

(1) a first light source, (2) a first spatial light modulating means disposed to receive light from said first light source, said first spatial light modulating means having a plurality of individually electrically controllable modulator cells for codulating light received from said first light source, and (3) a first viewing means for spatially localizing light modulated by said first spatial light modulating means to a first one of an observer'"'"'s eyes;

a second projection system including;

(1) a second light source, (2) a second spatial light modulating means disposed to receive light from said second light source, said second spatial light modulating means having a plurality of individually electrically controllable modulator cells for modulating light received from said second light source, and (3) a second viewing means for spatially localizing light modulated by said second spatial light modulating means to a second one of an observer'"'"'s eyes;

a viewing screen visible to both the first and second ones of the observer'"'"'s eyes, said viewing screen having means for reflecting most of the light received from a light source at a particular angle to a narrow range of angles corresponding to said particular angle;

said first viewing means comprises disposing said first projection system at a particular angle in relation to said vewing screen whereby light from said first projection system is reflected to a narrow range of angles corresponding to the location of the first one of the observer'"'"'s eyes in the expected viewing position; and

said second viewing means comprises disposing said second projection system at a particular angle in relation to said viewing screen whereby light from said second projection system is reflected to a narrow range of angles corresponding to the location of the second one of the observer'"'"'s eyes in the expected viewing position.