Image projection system engine assembly

• US 20020159034A1
• Filed: 04/12/2002
• Published: 10/31/2002
• Est. Priority Date: 10/17/1996
• Status: Active Grant

• Current Assignee: Duke University
• Original Assignee: Duke University
• Inventors: Knox, Richard M.
• Granted Patent: US 6,746,122 B2
• Time in Patent Office: Days
• US Class Current: 353/20
• CPC Class Codes: F21V 9/14 for producing polarised light
• CPC Class Codes: F21V 9/20 Dichroic filters, i.e. devices operating on the principle of wave interference to pass specific ranges of wavelengths while cancelling others
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: H01J 61/025 Associated optical elements
• CPC Class Codes: H01J 61/12 Selection of substances for gas fillings; Specified operating pressure or temperature
• CPC Class Codes: H01J 61/34 Double-wall vessels or containers
• CPC Class Codes: H01J 61/40 by light filters; by coloured coatings in or on the envelope
• CPC Class Codes: H01J 65/046 the field being produced by using capacitive means around the vessel
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• 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

A light projection engine uses a wide angle reflecting polarizer material (preferably 3M DBEF brand double brightness enhancement filter) as a polarizing beamsplitter to direct polarized light to beam splitter/combiner (such as an X-cube dichroic reflector). The beam splitter/combiner then splits the directed polarized light into separate reflective LCD panels acting as light valves. The LCD panels alter the polarity of the incident light from 0 degrees up to 90 degrees to control which light is passes from the wide angle reflecting polarizer back towards the light source and which light has the necessary polarization change to allow it to pass from the wide angle reflecting polarizer to the lens system. After reflecting off of the LCD panels, the light goes back through the X-cube dichroic reflector, where it is recombined. The recombined light which is of a first polarity is transmitted from the reflecting polarizer to the lens system, while the recombined light which is of a second polarity is transmitted to the light source. The LCDs are preferably analog polarizing LCDs.

Claims

1. A projection display apparatus comprising:

a light source providing a beam of light;

a wide angle reflecting polarizer for passing substantially all of a first polarized portion of the beam that is polarized in a first direction, and reflecting substantially all of a second polarized portion of the beam that is polarized in a second direction; and

an image engine that receives one of the first or second polarized portions and returns to said wide angle reflecting polarizer a polarized image in which the polarization of the one of the first or second polarized portions is shifted corresponding to an image to display to include components of the second or first polarized portion.

2. The apparatus of claim 1, wherein the wide angle reflecting polarizer comprises 3M DBEF.

3. The apparatus of claim 1, wherein the image engine further includes a beam splitter/combiner for splitting rays of polarized light received from the reflecting polarizer into plural color bands, wherein there is a reflecting polarizing LCD for each color band and an individual planar surface of the beam splitter/combiner for each color band, and each color band is directed substantially through its respective individual planar surface of the splitter/combiner to its respective reflecting polarizing LCD, and thence through its respective planar surface into the beam splitter/combiner, where the plural color bands are combined and transmitted to the wide angle reflecting polarizer.

4. The apparatus of claim 3, wherein the LCD is an analog LCD.

5. The apparatus of claim 1, wherein the image engine further includes a beam splitter/combiner for splitting rays of polarized light received from the reflecting polarizer into a first and second color band, wherein the first color band is passed through a color wheel/shutter to a single LCD for color sequential operation, and wherein the second color band is passed to a second LCD.

6. The apparatus of claim 1, further comprising a mirror for reflecting back to the light source light which is not transmitted to the image engine, wherein the light source reabsorbs and reemits at least a portion of the light which is not transmitted to the image engine.

7. The apparatus of claim 1, wherein the light source comprises a lamp and a reflecting polarizing filter for passing substantially all of the rays of polarized light which are polarized in the second direction and for reflecting substantially all of the other rays of light back into the lamp for energy recovery.

8. The apparatus of claim 1, wherein the light source comprises a lamp and a reflecting filter for passing substantially all rays of selected wavelength bands and for reflecting substantially all rays of light which are not in these bands back into the lamp for energy recovery.

9. The apparatus of claim 1, further comprising a means of modifying the direction of the rays of light.

10. The apparatus of claim 1, wherein the light source comprises:

i) an electrodeless lamp body that defines a chamber;

ii) a gas contained within the chamber;

iii) electrodes positioned externally of the lamp chamber for producing energy that excites the gas, forming a plasma light source of intense heat that emits a light beam;

iv) wherein the electrodes are not subjected to the intense heat generated at the plasma;

v) a reflector positioned next to the lamp body for redirecting some of the light emitted by the light source back to the lamp using the reflector so that the lamp reabsorbs light energy to intensify the light source; and

vi) wherein the reflector includes a polarizing filter that is positioned to receive and polarize the light beam.

11. The apparatus of claim 1, further comprising:

a projection apparatus for producing an image display on a display surface, the projection apparatus including;

i) a display surface;

ii) an optical device; and

iii) means for transmitting light from the lens to the display surface such that the light travels an image path which reaches the optical device twice on its way to the display surface,

wherein the optical device is reflective of some light and transmissive of other light.

12. The apparatus of claim 1, wherein the image engine receives the first polarized portion passed through said wide angle reflecting polarizer.

13. The apparatus of claim 1, wherein the image engine receives the second polarized portion reflected from said wide angle reflecting polarizer.

14. The apparatus of claim 1, wherein the beam of light is directed by the light source to the wide angle reflecting polarizer at an angle substantially 45°

from a surface formed by the reflecting polarizer.

15. The apparatus of claim 1, wherein the beam of light is directed by the light source to the wide angle reflecting polarizer at an angle other than substantially 45°

from a surface formed by the reflecting polarizer.

17. The method of claim 16, wherein the wide angle reflecting polarizer comprises 3M DBEF.

18. The method of claim 16, further comprising reflecting back to the light source which is not part of the image to be displayed.

19. The method of claim 16, wherein the light source comprises a lamp and a reflecting polarizing filter for passing substantially all of the rays of polarized light which are polarized in the second direction and for reflecting substantially all of the other rays of light back into the lamp for energy recovery.

20. The method of claim 16, wherein the light source comprises a lamp and a reflecting filter for passing substantially all rays of selected wavelength bands and for reflecting substantially all rays of light which are not in these bands back into the lamp for energy recovery.

21. The method of claim 16, wherein the image engine includes a spatial light modulator.

22. The method of claim 16, further comprising modifying the direction of the rays of light.

23. The method of claim 16, wherein the source of rays of polarized light comprises:

i) an electrodeless lamp body that defines a chamber;

ii) a gas contained within the chamber;

iii) electrodes positioned-eternally of the lamp chamber for producing energy that excites the gas, forming a plasma light source of intense heat that emits a light beam;

iv) wherein the electrodes are not subjected to the intense heat generated at the plasma;

v) a reflector positioned next to the lamp body for redirecting some of the light emitted by the light source back to the lamp using the reflector so that the lamp reabsorbs light energy to intensify the light source; and

vi) wherein the reflector includes a polarizing filter that is positioned to receive and polarize the light beam.

24. The method of claim 16, further comprising providing a projection apparatus for producing an image display on a display surface, the projection apparatus comprising:

i) a display surface;

ii) an optical device; and

iii) means for transmitting light from the lens to the display surface such that the light travels an image path which reaches the optical device twice on its way to the display surface,

wherein the optical device is reflective of some light and transmissive of other light.

26. The apparatus of claim 25, wherein the wide angle reflecting polarizer comprises 3M DBEF.

27. The apparatus of claim 25, wherein the first, second, and third color of light rays are respectively red, green, and blue light rays.

29. The apparatus of claim 28, wherein the wide angle reflecting polarizer comprises 3M DBEF.

30. The apparatus of claim 28, wherein the first color band is green and blue and wherein the second color band is red.

16. A method of producing a visual image comprising:

(a) providing a light source providing a beam of light;

(b) directing the light onto a wide angle reflecting polarizer for passing substantially all of a first portion of the beam which is polarized in a first direction and for reflecting substantially all of a second portion of the beam which is polarized in a second direction;

(c) receiving one of the first or second portions in an image engine;

(d) shifting the polarity of the one of the first or second portions corresponding to an image to be displayed to include components of the second or first portion to yield a polarized image; and

(e) returning the polarized image to the wide angle reflecting polarizer.

25. A projection display apparatus comprising:

(a) a source of rays of polarized light;

(b) a wide angle reflecting polarizer aligned at an angle to the rays of polarized light for passing substantially all of the rays of polarized light which are polarized in a first direction and for reflecting substantially all of the rays of polarized light which are polarized in a second direction;

(c) a beam splitter/combiner, having a first, primary incidence plane aligned at an angle to the wide angle reflecting polarizer, for splitting incident rays of polarized light from the reflecting polarizer into a first, second, and third color of light rays;

(d) a first reflecting polarizing LCD for receiving the first color of light rays from the beam splitter/combiner, shifting the polarization of none, some, or all of the first color of light rays, and directing the first color of light rays back into the beam splitter/combiner;

(e) a second reflecting polarizing LCD for receiving the second color of light rays from the beam splitter/combiner, shifting the polarization of none, some, or all of the second color of light rays, and directing the second color of light rays back into the beam splitter/combiner;

(f) a third reflecting polarizing LCD for receiving the third color of light rays from the beam splitter/combiner, shifting the polarization of none, some, or all of the third color of light rays, and directing the third color of light rays back into the beam splitter/combiner; and

(g) a lens for receiving and transmitting substantially all of the rays of polarized light whose polarity has been shifted and which have passed from the beam splitter/combiner to the wide angle reflecting polarizer.

28. A projection display apparatus comprising:

(a) a source of rays of polarized light;

(b) a wide angle reflecting polarizer aligned at an angle to the rays of polarized light for passing substantially all of the rays of polarized light which are polarized in a first direction and for reflecting substantially all of the rays of polarized light which are polarized in a second direction;

(c) a beam splitter/combiner, having a first, primary incidence plane aligned at an angle to the wide angle reflecting polarizer, for splitting incident rays of polarized light from the reflecting polarizer into a first and second color bands of rays;

(d) a color wheel/shutter for receiving the first color band of rays from the beam splitter/combiner and for sequentially passing rays of a first color and of a second color in the first color band;

(e) a first reflecting polarizing LCD for receiving the sequentially passed rays of the first color and of the second color in the first color band, for shifting the polarization of none, some, or all of the sequentially passed rays, and for directing the rays back into the beam splitter/combiner;

(f) a second reflecting polarizing LCD for receiving the second color band for rays from the beam splitter/combiner, for shifting the polarization of none, some, or all of the second color band of rays, and for directing the rays back into the beam splitter/combiner; and

(g) a lens for receiving and transmitting substantially all of the rays of polarized light whose polarity has been shifted and which have passed from the beam splitter/combiner to the wide angle reflecting polarizer.

31. A projection system comprising:

(a) a source of rays of polarized light;

(b) a wide angle reflecting polarizer aligned at an angle to the rays of polarized light for passing substantially all of the rays of polarized light which are polarized in a first direction and for reflecting substantially all of the rays of polarized light which are polarized in a second direction;

(c) a beam splitter/combiner, having a first, primary incidence plane aligned at an angle to the wide angle reflecting polarizer, for splitting incident rays of polarized light from the reflecting polarizer into a first, second, and third color of light rays;

(d) a first reflecting polarizing LCD for receiving the first color of light rays from the beam splitter/combiner, shifting the polarization of none, some, or all of the first color of light rays, and directing the first color of light rays back into the beam splitter/combiner;

(e) a second reflecting polarizing, LCD for receiving the second color of light rays from the beam spitter/combiner, shifting the polarization of none, some, or all of the second color of light rays, and directing the second color of light rays back into the beam splitter/combiner;

(f) a third reflecting polarizing LCD for receiving the third color of light rays from the beam splitter/combiner, shifting the polarization of none, some, or all of the third color of light rays, and directing the third color of light rays back into the beam splitter/combiner;

(g) a lens for receiving and transmitting substantially all of the rays of polarized light whose polarity has been shifted and which have passed from the beam splitter/combiner to the wide angle reflecting polarizer; and

(h) a display surface for receiving rays from the lens.

32. The apparatus of claim 31, further comprising:

an optical device interposed between the lens and the display surface such that the rays travel an image path which reaches the optics twice before reaching the display surface, wherein the optical device is reflective of some light and transmissive of other light.

33. The apparatus of claim 31, wherein the wide angle reflecting polarizer comprises 3M DBEF.

34. The apparatus of claim 31, wherein the first, second, and third color of light rays are respectively red, green, and blue light rays.

36. The apparatus of claim 35, further comprising:

an optical device interposed between the lens and the display surface such that the rays travel an image path which reaches the optics twice before reaching the display surface, wherein the optical device is reflective of some light and transmissive of other light.

37. The apparatus of claim 35, wherein the wide angle reflecting polarizer comprises 3M DBEF.

38. The apparatus of claim 35, wherein the first color band is green and blue and wherein the second color band is red.

40. The apparatus of claim 39, wherein the wide angle reflecting polarizer comprises 3M DBEF.

41. The apparatus of claim 39, wherein the image engine further includes a beam splitter/combiner for splitting rays of polarized light received from the reflecting polarizer into plural color bands, wherein there is a reflecting polarizing LCD for each color band and an individual planar surface of the beam splitter/combiner for each color band, and each color band is directed substantially through its respective individual planar surface of the splitter/combiner to its respective reflecting polarizing LCD, and thence through its respective planar surface into the beam splitter/combiner, where the plural color bands are combined and transmitted to the wide angle reflecting polarizer.

42. The apparatus of claim 41, wherein the LCD is an analog LCD.

43. The apparatus of claim 39, wherein the image engine further includes a beam splitter/combiner for splitting rays of polarized light received from the reflecting polarizer into a first and second color band, wherein the first color band is passed through a color wheel/shutter to a single LCD for color sequential operation, and wherein the second color band is passed to a second LCD.

44. The apparatus of claim 39 for use with a the light source capable of reabsorbing and reemiting light, the apparatus further comprising a mirror for reflecting back to the light source light which is not transmitted to the image engine for reabsorbtion and reemission.

45. The apparatus of claim 39, further comprising a means of modifying the direction of the rays of light.

46. The apparatus of claim 39, further comprising:

a projection apparatus for producing an image display on a display surface, the projection apparatus including;

i) a display surface;

ii) an optical device; and

iii) means for transmitting light from the lens to the display surface such that the light travels an image path which reaches the optical device twice on its way to the display surface,

wherein the optical device is reflective of some light and transmissive of other light.

47. The apparatus of claim 39, wherein the image engine receives the first polarized portion passed through said wide angle reflecting polarizer.

48. The apparatus of claim 39, wherein the image engine receives the second polarized portion reflected from said wide angle reflecting polarizer.

49. The apparatus of claim 39, wherein the beam of light is directed from the light source to the wide angle reflecting polarizer at an angle substantially 45°

from a surface formed by the reflecting polarizer.

50. The apparatus of claim 39, wherein the beam of fight is directed from the light source to the wide angle reflecting polarizer at an angle other than substantially 45°

from a surface formed by the reflecting polarizer.

35. A projection display apparatus comprising:

(a) a source of rays of polarized light;

(b) a wide angle reflecting polarizer aligned at an angle to the rays of polarized light for passing substantially all of the rays of polarized light which are polarized in a first direction and for reflecting substantially all of the rays of polarized light which are polarized in a second direction;

(c) a beam splitter/combiner, having a first, primary incidence plane aligned at an angle to the wide angle reflecting polarizer, for splitting incident rays of polarized light from the reflecting polarizer into a first and second color bands of rays;

(d) a color wheel/shutter for receiving the first color band of rays from the beam splitter/combiner and for sequentially passing rays of a first color and of a second color in the first color band;

(e) a first reflecting polarizing LCD for receiving the sequentially passed rays of the first color and of the second color in the first color band, for shifting the polarization of none, some, or all of the sequentially passed rays, and for directing the rays back into the beam splitter/combiner;

(f) a second reflecting polarizing LCD for receiving the second color band for rays from the beam splitter/combiner, for shifting the polarization of none, some, or all of the second color band of rays, and for directing the rays back into the beam splitter/combiner;

(g) a lens for receiving and transmitting substantially all of the rays of polarized light whose polarity has been shifted and which have passed from the beam splitter/combiner to the wide angle reflecting polarizer; and

(h) a display surface for receiving rays from the lens.

39. A projection display engine apparatus that receives a beam of fight from a light source, comprising:

a wide angle reflecting polarizer for passing substantially all of a first polarized portion of the beam that is polarized in a first direction, and reflecting substantially all of a second polarized portion of the beam that is polarized in a second direction; and

an image engine that receives one of the first or second polarized portions and returns to said wide angle reflecting polarizer a polarized image in which the polarization of the one of the first or second polarized portions is shifted corresponding to an image to display to include components of the second or first polarized portion.