Holographic projector

• US 20050286101A1
• Filed: 04/07/2005
• Published: 12/29/2005
• Est. Priority Date: 04/13/2004
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Garner, Harold R., Huebschman, Michael L., Munjuluri, Bala Nagendra Raja
• Granted Patent: US 7,738,151 B2
• Time in Patent Office: Days
• US Class Current: 359/9
• CPC Class Codes: G03H 1/02 Details of features involved during the holographic process; Replication of holograms without interference recording
• CPC Class Codes: G03H 1/08 Synthesising holograms, i.e. holograms synthesized from objects or objects from hologramsusing electric digital computers G06F; G06T
• CPC Class Codes: G03H 1/2205 using downstream optical component
• CPC Class Codes: G03H 1/2249 Holobject properties
• CPC Class Codes: G03H 1/2294 Addressing the hologram to an active spatial light modulator
• CPC Class Codes: G03H 2001/0216 Optical components G03H2001/0224, G03H1/0256 take precedence; corresponding details, see subgroups of G03H2223/00
• CPC Class Codes: G03H 2001/0833 Look up table
• CPC Class Codes: G03H 2001/2213 Diffusing screen revealing the real holobject, e.g. container filed with gel to reveal the 3D holobject
• CPC Class Codes: G03H 2001/2218 being perpendicular to optical axis
• CPC Class Codes: G03H 2001/2231 Reflection reconstruction
• CPC Class Codes: G03H 2001/2271 RGB holobject
• CPC Class Codes: G03H 2001/2297 using frame sequential, e.g. for reducing speckle noise
• CPC Class Codes: G03H 2001/303 Interleaved sub-holograms, e.g. three RGB sub-holograms having interleaved pixels for reconstructing coloured holobject
• CPC Class Codes: G03H 2210/30 3D object
• CPC Class Codes: G03H 2210/33 3D/2D, i.e. the object is formed of stratified 2D planes, e.g. tomographic data
• CPC Class Codes: G03H 2210/454 into planes
• CPC Class Codes: G03H 2210/562 Holographic object, i.e. a combination of an object and holobject G03H1/20 takes precedence
• CPC Class Codes: G03H 2222/18 RGB trichrome light
• CPC Class Codes: G03H 2223/14 Diffuser, e.g. lens array, random phase mask
• CPC Class Codes: G03H 2225/24 Having movable pixels, e.g. microelectromechanical systems [MEMS]
• CPC Class Codes: G03H 2225/60 : Multiple SLMs
• CPC Class Codes: G03H 2226/02 : Computing or processing means, e.g. digital signal processor [DSP]
• CPC Class Codes: G03H 2240/56 : Resolution

Abstract

The present invention relates to an apparatus and method for displaying three-dimensional images. The device of the present invention displays a holographic transform reflected from a light modulation device onto an active image reconstructor to create real-time, three-dimensional moving holograms from a single light beam.

Claims

1. A projection device comprising:

a coherent light beam-generator that generates a light beam;

a beam expander disposed to receive the light beam and to emit an expanded light beam;

a digital micro-mirror device disposed to receive a holographic transform and to display the holographic transform for illumination by the expanded light beam into a holographic light beam;

a lens disposed to receive and modulate the holographic light beam; and

an image reconstructor that receives and emits a 3-dimensional holographic image.

2. The device of claim 1, wherein the lens is a convergent or a divergent lens.

3. The device of claim 1, further comprising two or more colored lasers added such that the three primary colors (red, green and blue) can illuminate the digital micro-mirror device at different portions of the digital micro-mirror with different wavelengths of laser light;

and

a holographic transform that comprises different color transforms disposed on the digital micro-mirror device to match the location of the two or more colored laser to display full color images.

4. The device of claim 1, further comprising two or more digital micro-mirror devices that display individual color displaying holograms based on illumination with different wavelengths of light;

and

two or more colored lasers such that the three primary colors (red, green and blue) illuminate at least one of the two or more digital micro-mirror device to display multi-colored images.

5. The device of claim 3, wherein a rotating wheel with narrow bandwidth filters to select colors from a multispectral light source replaces the two or more colored lasers and to illuminate the digital micro-mirror device disposed with the appropriately synchronized holographic transform to display full color images.

6. The device of claim 1, wherein

a non-coherent, white-light beam-generator that generates a light beam;

and

a narrow bandwidth filter disposed to select out of the white light one color with a narrow bandwidth replaces the coherent light beam-generator.

7. The device of claim 6, wherein the non-coherent white-light beam-generator is replaced with a non-coherent or near-coherent diode light beam generator and the narrow bandwidth filter is used with diodes which do not produce narrow enough wavebands commensurate with the digital micro-mirror device mirror size.

8. The device of claim 1, wherein the image reconstructor is a volumetric display.

9. The device of claim 8, wherein the image reconstructor comprises one or more liquid crystal plates.

10. The device of claim 9, wherein the modulation by the one or more liquid crystal plates of the holographic light beam is asynchronous to the holographic transform frame-rate deposition on the digital micro-mirror device.

11. The devices of claim 9, wherein the modulation using one or more liquid crystal plates is controlled by a power conditioning circuit to operate the one or more liquid crystal plates without flicker and to adjust the appropriate opacity/translucency of each of the one or more liquid crystal plates.

12. The device of claim 9, wherein the one or more liquid crystal plates are surfaced with anti-reflection coating to improve transmitted intensity.

13. The device of claim 8, wherein the image reconstructor comprises a continuous medium in a gel tank.

14. The device of claims 8, wherein the image reconstructor comprises one or more frosted plates or translucent sheets which may be translated or rotated.

15. The device of claim 8, wherein the image reconstructor comprises a mist, micro-particles or vapor in free space or enclosed in a tank.

16. The device of claim 1, wherein the position or angle of the light beam is shifted by less than the width of a mirror on the digital micro-mirror device to provide a shifted superimposed image for higher resolution.

17. The device of claim 1, wherein the wavelength of the light beam is shifted such that the reconstructed image position is shifted by less than the width of a mirror on the

digital micro-mirror device to provide a shifted superimposed image for higher resolution.

18. The device of claim 1, wherein either the expanded light beam or the digital micro-mirror device is moved by some fraction of the resolution spacing to provide a shifted superimposed image for higher resolution.

19. The device of claim 1, wherein the wavelength of expanded light beam is shifted such that the grating effect of the digital micro-mirror device causes a shift in the reconstructed image by less than the resolution spacing and thus enhances resolution while using the same or different holograms for each of the shifted wavelengths.

20. The device of claim 1, wherein digital micro-mirror device receives different holograms that reconstruct the 3-dimensional holographic image shifted by fractions of the basic resolution.

21. The device of claim 1, further comprising one or more lenses, mirrors or combinations thereof, whereby the 3-dimensional holographic image is magnified or demagnified.

22. The device of claim 1, wherein a digital hologram is resized smaller than recorded and imaged to the digital micro-mirror device to produce a larger reconstructed image when illuminated with the same wavelength of light of the original hologram.

23. The device of claim 1, wherein a digital hologram is resized smaller than recorded and imaged to the digital micro-mirror device to produce a larger reconstructed image when illuminated with the same wavelength of light is resized larger than recorded and disposed to the digital micro-mirror device to produce a smaller reconstructed image when illuminated with the same wavelength of light of the original hologram.

24. The device of claim 1, wherein a digital hologram disposed to the digital micro-mirror device is illuminated with a wavelength of light longer than the wavelength used to produce the original hologram in order to produce a image which is larger than the original object recorded in the hologram.

25. The device of claim 1, wherein a digital hologram disposed to the digital micro-mirror device is illuminated with a wavelength of light longer than the wavelength used to produce the original hologram in order to produce a digital hologram disposed to the digital micro-mirror device is illuminated with a wavelength of light shorter than the wavelength used to produce the original hologram in order to produce a image which is smaller than the original object recorded in the hologram.

26. The device of claim 23, wherein combinations of resizing of the hologram and using longer or shorter wavelengths are used to dispose a particular magnification on the reconstructed image.

27. The device of claim 1, wherein the digital micro-mirror device is illuminated at an optimal angle to enable larger viewing because of increase in distance between multiple diffraction orders.

28. The device of claim 1, wherein the optimal focal length of the lens is used to display only one of the two complex conjugate images at a time.

29. The device of claim 1, wherein arrays of digital micro-mirror device are used to decrease depth of focus of different layers in the displayed three dimensional holographic image.

30. The device of claim 1, wherein using multiple digital micro-mirror device increases the viewing angle (look-around angle) of the displayed image.

31. The device of claim 1, wherein an optimal distance of the holographic plane from the 3D scene for recording or computing holograms is used to display virtual images that can be easily observed by human eye.

32. The device of claim 1, wherein multiple orders can be removed from the holographic image by manufacturing the digital micro-mirror device with mirrors in irregular patterns thus reducing or eliminating the grating effect multiple orders for small bandwidth illumination.

33. The device of claim 1, wherein the device is coupled by land-line or airwaves to a hologram recording system which has a CCD camera or similar digital recording device to feed the recorded hologram via the computer to the digital micro-mirror device.

34. The device of claim 33, wherein information of three dimensional scenes by selectively recording depth information using a reference beam to modulate time-selection at the desired depth of hologram construction on the CCD or similar device.

35. The device of claim 33, wherein longer wavelengths of coherent light are used to display the 3-dimensional holographic image using a shorter wavelength light to illuminate the digital micro-mirror device in order to accommodate for the difference in size of pixels of digital micro-mirror device and CCD camera.

36. The device of claim 33, wherein one or more pixel values of a hologram transform are computed and transcribed to digital micro-mirror device using the pixel values of the digital hologram recorded using CCD camera to accommodate for the difference in size of pixels of digital micro-mirror device and CCD camera.

37. The device of claim 33, wherein a hologram is synthesized by the addition of recorded holograms on individual layers of a three dimensional scene on the digital micro-mirror device.

38. The device of claim 33, wherein the recording device records at wavelengths, either sonic or electromagnetic, longer than visible wavelengths and the hologram transforms are made with the longer than visible wavelengths are disposed to the digital micro-mirror device, wherein the digital micro-mirror device is illuminated with narrowband visible wavelength light and the image is reconstructed at a de-magnified size relative to the original scene.

39. The device of claim 33, wherein the recording device records at wavelengths, either deBroglie or electromagnetic, shorter than visible wavelengths and the holograms transform are made with the shorter than visible wavelengths are disposed to the digital micro-mirror device, wherein the digital micro-mirror device is illuminated with narrowband visible wavelength light and the image is reconstructed at a magnified size relative to the original scene.

40. The device of claims 38, further comprising one or more lenses, mirrors or combinations thereof, wherein the 3-dimensional holographic image is magnified or demagnified;

and

wherein combinations of resizing of the hologram and using longer or shorter wavelengths are used to dispose a particular magnification on the reconstructed image to further adjust magnifications.

41. A projection device comprising:

a coherent light beam-generating device that produces one or more expanded light beams;

a digital micro-mirror device connected to a processor to display a holographic transform thereon and disposed to receive and reflect the expanded light beam into a holographic light beam;

a lens disposed to receive and modulate the holographic light beam; and

an active image reconstructor that receives the holographic light beam and modulates the holographic light beam.

42. The device of claim 41, wherein Rhodopsium or similar type material replaces the active image reconstructor and is imprinted with one or more holograms at a finer resolution using the digital micro-mirror device and is erased by another laser beam and an image is reconstructed into a three dimensional images at video rate.

43. A 3D display device comprising:

a coherent light beam-generator that generates a light beam;

a beam expander disposed to receive the light beam and to emit an expanded light beam; and

a digital micro-mirror device disposed to receive a holographic transform and to display the holographic transform for illumination by the expanded light beam into a holographic light beam, wherein the human eye perceives the image in the holographic light beam.

44. A method of creating a hologram comprising:

generating an expanded light beam;

disposing a pattern derived from an image or model on a surface of a digital micro-mirror device disposed to receive the expanded light beam;

generating a modulated light pattern; and

focusing the modulated light pattern onto a image reconstructor.

45. The method of claim 44, further comprising the step of computing the hologram in real time using pre-computed terms to update the position, add new objects, generate a 3D scene or combination thereof, and disposing the hologram on the digital micro-mirror device.

46. The method of claim 44, further comprising the step of encoding the hologram into image format by selective amplification and scaling of intensities at certain values that would produce higher intensity reconstruction images disposed to the digital micro-mirror device.

47. The method of claim 44, further comprising the step of computing the hologram utilizing similar techniques used for computation of Fast Fourier Transforms (FFTs) or using FFTs as intermediate steps is disposed to the digital micro-mirror device.

48. The method of claim 44, further comprising the step of computing the hologram to display full color image by compensating for the diffraction grating effect of the digital micro-mirror device which shifts positions as a function of the wavelength is disposed to the digital micro-mirror device.

49. The method of claim 44, further comprising the step of computing the hologram to display full color image by compensating for the loss of intensity as light traverse multiple layers a spatial light modulator.

50. The method of claim 44, further comprising the step of computing the hologram by modulating intensities and spatial size variations of each layer in the three dimensional image in order to display the 3D image with true perspectives required to perceive depth is disposed to the digital micro-mirror device.

51. The method of claim 44, further comprising the step of modulating intensities and spatial size variations of each layer in the three dimensional image to display virtual image with all the perspectives required to perceive depth is disposed to the digital micro-mirror device.