Autostereoscopic display and spatial light modulator

• US 5,917,562 A
• Filed: 12/15/1995
• Issued: 06/29/1999
• Est. Priority Date: 12/16/1994
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Harrold, Jonathan, Woodgate, Graham John, Ezra, David, Raynes, Edward Peter, Omar, Basil Arthur
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): TON, MINH TOAN T
• Application Number:
  US08/573,155
• Time in Patent Office: 1,292 Days
• US Class Current: 349/15
• CPC Class Codes: G02B 30/25 using polarisation techniques
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133565 inside the LC elements, i.e. between the cell substrates
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 1/133631 with a spatial distribution of the retardation value
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: H04N 13/286 having separate monoscopic and stereoscopic modes
• CPC Class Codes: H04N 13/305 using lenticular lenses, e.g. arrangements of cylindrical lenses
• CPC Class Codes: H04N 13/31 using parallax barriers
• CPC Class Codes: H04N 13/32 using arrays of controllable light sources; using moving apertures or moving light sources
• CPC Class Codes: H04N 13/324 Colour aspects
• CPC Class Codes: H04N 13/337 using polarisation multiplexing
• CPC Class Codes: H04N 13/341 using temporal multiplexing
• CPC Class Codes: H04N 13/346 using prisms or semi-transparent mirrors
• CPC Class Codes: H04N 13/349 Multi-view displays for displaying three or more geometrical viewpoints without viewer tracking for viewing without the aid of special glasses using fly-eye lenses H04N13/307
• CPC Class Codes: H04N 13/361 Reproducing mixed stereoscopic images; Reproducing mixed monoscopic and stereoscopic images, e.g. a stereoscopic image overlay window on a monoscopic image background
• CPC Class Codes: H04N 13/376 for tracking left-right translational head movements, i.e. lateral movements
• CPC Class Codes: H04N 13/378 for tracking rotational head movements around an axis perpendicular to the screen
• CPC Class Codes: H04N 13/38 for tracking vertical translational head movements
• CPC Class Codes: H04N 13/398 Synchronisation thereof; Control thereof

Abstract

An autostereoscopic display of the invention includes: an illumination source for producing light of a first polarization and light of a second polarization different from the first polarization; a spatial light modulator for modulating the light of the first polarization and the light of the second polarization from the illumination source; and an optical system for directing the light of the first polarization to a first viewing region and the light of the second polarization to a second viewing region, wherein the spatial light modulator includes: a first polarization adjusting member for transmitting the light of the first polarization and substantially preventing transmission of the light of the second polarization; a second polarization adjusting member for transmitting the light of the second polarization and substantially preventing transmission of the light of the first polarization; and first and second groups of picture elements optically aligned with the first and second polarization adjusting member, respectively.

Claims

1. An autostereoscopic display comprising:

an illumination source for producing light of a first polarization and light of a second polarization different from the first polarization;

a spatial light modulator for modulating the light of the first polarization and the light of the second polarization from the illumination source; and

an optical system for directing the light of the first polarization to a first viewing region and the light of the second polarization to a second viewing region,

wherein the spatial light modulator includes;

first polarization adjusting means for transmitting the light of the first polarization and substantially preventing transmission of the light of the second polarization;

second polarization adjusting means for transmitting the light of the second polarization and substantially preventing transmission of the light of the first polarization; and

first and second groups of picture elements optically aligned with the first and second polarization adjusting means, respectively.

2. An autostereoscopic display as claimed in claim 1, wherein the light of the first polarization is light polarized in a first direction and the light of the second polarization is light polarized in a second direction of polarization, the first direction being orthogonal to the second direction.

3. An autostereoscopic display as claimed in claim 1, wherein the first and second polarization adjusting means are disposed between a modulating layer of the spatial light modulator and the illumination source.

4. An autostereoscopic display as claimed in claim 1, wherein the optical system is disposed between the illumination source and the spatial light modulator.

5. An autostereoscopic display as claimed in claim 1, wherein the illumination source comprises at least one light source and a plurality of polarizers.

6. An autostereoscopic display as claimed in claim 1, wherein the picture elements of the first group alternate with the picture elements of the second group.

7. An autostereoscopic display as claimed in claim 1, further comprising a control circuit for controlling the first and second groups of picture elements to display first and second images, respectively, of a stereoscopic pair of images.

8. An autostereoscopic display as claimed in claim 1, wherein the illumination source comprises a single source of light and polarizing means for converting the light emitted therefrom to the light of the first polarization and the light of the second polarization.

9. An autostereoscopic display as claimed in claim 8, wherein the polarizing means comprises a polarizing sheet and a liquid crystal layer switchable between a state in which the polarization of light passing through the liquid crystal layer is rotated by 90 (2m) degrees where m is an integer, and a state in which the liquid crystal rotates the polarization axis by 90(2n+1) degrees where n is an integer.

10. An autostereoscopic display as claimed in claim 1, wherein the spatial light modulator comprises first and second substrates arranged to define therebetween a cell containing a liquid crystal layer;

and wherein the spatial light modulator includes a plurality of picture elements which operate in the same mode and polarization adjusters which are provided for the respective picture elements and are disposed inside the cell, the picture elements being arranged as first and second sets, the polarization adjusters of the picture elements of the first set transmitting the light of the first polarization between the first substrate and the liquid crystal layer, the polarization adjusters of the picture elements of the second set transmitting the light of the second polarization between the first substrate and the liquid crystal layer.

11. An autostereoscopic display as claimed in claim 10, wherein the picture elements operate in the normally black mode.

12. An autostereoscopic display as claimed in claim 10, wherein the picture elements operate in the normally white mode.

13. An autostereoscopic display as claimed in claim 1, wherein the illumination source is switchable so as to provide unpolarized light or light having a single polarization which is transmitted by at least either one of the first polarization adjusting means and second polarization adjusting means.

14. An autostereoscopic display as claimed in claim 13, wherein the illumination system is switchable so as to function as a Lambertian source.

15. An autostereoscopic display as claimed in claim 13, further comprising a control circuit for controlling the first and second groups of picture elements to display a two dimensional image with the picture elements of the first and second groups displaying different picture elements of the two dimensional image.

16. An autostereoscopic display as claimed in claim 1, wherein the first group of picture elements outputs light of a third polarization and the second group of picture elements is outputs light of a fourth polarization different from the third polarization.

17. An autostereoscopic display as claimed in claim 16, wherein the third polarization and the fourth polarization are orthogonal.

18. An autostereoscopic display as claimed in claim 16, further comprising polarizing glasses having first and second polarizers for passing the light of the third polarization and the light of the fourth polarization, respectively.

19. An autostereoscopic display as claimed in claim 1, wherein the spatial light modulator is rotatable so as to reverse the direction of light passing therethrough for stereoscopic operation.

20. A spatial light modulator including first and second substrates defining therebetween a cell containing a liquid crystal layer, the modulator comprising a plurality of pixels which operate in the same mode and respectively including polarization adjusters disposed within the cell, the pixels being arranged as first and second sets, the polarization adjusters of the pixels of the first set transmitting light of a first polarization between the first substrate and the liquid crystal layer, the polarization adjusters of the pixels of the second set transmitting light of a second polarization which is different from the first polarization between the first substrate and the liquid crystal layer.

21. A modulator as claimed in claim 20, wherein the pixels of the first set are interleaved with the pixels of the second set.

22. A modulator as claimed in claim 20, wherein the second polarization is substantially orthogonal to the first polarization.

23. A modulator as claimed in claim 20, the first polarization and the second polarization are linear polarizations.

24. A modulator as claimed in claim 22, the first polarization and the second polarization are circular polarizations of opposite handedness.

25. A modulator as claimed in claim 20, wherein the pixels operate in the normally black mode.

26. A modulator as claimed in claim 20, wherein the pixels operate in the normally white mode.

27. A modulator as claimed in claim 20, wherein each of the polarization adjusters comprises an element which is distinct from the liquid crystal layer.

28. A modulator as claimed in claim 20, wherein the liquid crystal layer contains at least one anisotropic dye to form a guest-host layer constituting at least one of the polarization adjusters.

29. A modulator as claimed in claim 20, wherein each of the polarization adjusters of the pixels of the first set comprises a first linear polarizer having a first polarization direction, and each of the polarization adjuster of the pixels of the second set comprises a second linear polarizer having a second polarization direction substantially orthogonal to the first polarization direction.

30. A modulator as claimed in claim 29, wherein the pixels of the first set respectively comprise third linear polarizers having a third polarization direction disposed between the liquid crystal layer and the second substrate, and wherein pixels of the second set respectively comprise fourth linear polarizers having a fourth polarization direction substantially perpendicular to the third polarization direction disposed between the liquid crystal layer and the second substrate.

31. A modulator as claimed in claim 29, wherein first rotation adjusters are provided for the respective pixels and are disposed between the liquid crystal layer and the second substrate;

the polarization rotations of the first rotation adjusters of the pixels of the first and second sets differ by substantially 90 degrees; and

a fifth linear polarizer is arranged to pass light having a fifth polarization direction passing through the second substrate.

32. A modulator as claimed in claim 20, wherein each of the polarization adjusters of the pixels of the first set comprises a first linear polarizer having a first polarization direction and a first rotation adjuster;

each of the polarization adjusters of the pixels of the second set comprises a second linear polarizer having a second polarization direction substantially perpendicular to the first polarization direction and a second rotation adjuster; and

the first and second rotation adjusters are disposed between the liquid crystal layer and the first and second polarizers, respectively, and provide polarization rotations which differ by substantially 90 degrees.

33. A modulator as claimed in claim 32, further comprising a fifth linear polarizer arranged to pass light having a fifth polarization direction passing through the second substrate.

34. A modulator as claimed in claim 32, wherein each of the pixels of the first set comprises a third linear polarizer having a third polarization direction disposed between the liquid crystal layer and the second substrate;

each of the pixels of the second set comprises a fourth linear polarizer having a fourth polarization direction substantially perpendicular to the third polarization direction disposed between the liquid crystal layer and the second substrate; and

each of the pixels includes a third rotation adjuster disposed between the liquid crystal layer and the third and fourth linear polarizers, the polarization rotation of the third rotation adjuster of each of the pixels of the first set differing from the polarization rotation of the third rotation adjuster of each of the pixels of the second set by substantially 90 degrees.

35. A modulator as claimed in claim 20, wherein the polarization adjusters of the pixels of the first and second sets comprise second and third rotation adjusters, respectively, providing rotations which differ by substantially 90 degrees and a sixth linear polarizer disposed between the liquid crystal layer and the second and third rotation adjusters.

36. A modulator as claimed in claim 20, wherein the polarization adjusters of the pixels of the first and second sets comprise first positive and negative quaterwave plates, respectively, and a sixth linear polarizer disposed between the liquid crystal layer and the first positive and negative quarterwave plates.

37. A modulator as claimed in claim 35, further comprising a fifth linear polarizer arranged to pass light having a fifth polarization direction passing through the second substrate.

38. A modulator as claimed in claim 36, further comprising a fifth linear polarizer arranged to pass light having a fifth polarization direction passing through the second substrate.

39. A modulator as claimed in claim 35, wherein the pixels respectively include first rotation adjusters disposed between the liquid crystal layer and the second substrate;

a polarization rotation of the first rotation adjusters of the pixels of the first set differs from that of the pixels of the second set by substantially 90 degrees; and

a fifth linear polarizer is disposed between the liquid crystal layer and the first rotation adjusters.

40. A modulator as claimed in claim 36, wherein the pixels respectively include first rotation adjusters disposed between the liquid crystal layer and the second substrate;

a polarization rotation of the first rotation adjusters of the pixels of the first set differs from that of the pixels of the second set by substantially 90 degrees; and

a fifth linear polarizer is disposed between the liquid crystal layer and the first rotation adjusters.

41. A modulator as claimed in claim 35, further comprising:

second positive and negative quarterwave plates disposed between the liquid crystal layer and the second substrate; and

a fifth linear polarizer disposed between the liquid crystal layer and the second positive and negative quarterwave plates.

42. A modulator as claimed in claim 36, further comprising:

second positive and negative quarterwave plates disposed between the liquid crystal layer and the second substrate; and

a fifth linear polarizer disposed between the liquid crystal layer and the second positive and negative quarterwave plates.

43. A modulator as claimed in claim 20, further comprising a quarterwave plate for passing light passing through the second substrate.

44. A modulator as claimed in claim 29, wherein each of the pixels of the first set comprises a first alignment layer disposed between the first linear polarizer and the liquid crystal layer and having an alignment direction substantially perpendicular to the first polarization direction, and wherein each of the pixels of the second set comprises a second alignment layer disposed between the second linear polarizer and the liquid crystal layer and having an alignment direction substantially perpendicular to the second polarization direction.

45. A modulator as claimed in claim 32, wherein each of the pixels of the first set comprises a first alignment layer disposed between the first linear polarizer and the liquid crystal layer and having an alignment direction substantially perpendicular to the first polarization direction, and wherein each of the pixels of the second set comprises a second alignment layer disposed between the second linear polarizer and the liquid crystal layer and having an alignment direction substantially perpendicular to the second polarization direction.

46. A modulator as claimed in claim 35, wherein each of the pixels of the first set comprises a first alignment layer disposed between the first linear polarizer and the liquid crystal layer and having an alignment direction substantially perpendicular to the first polarization direction, and wherein each of the pixels of the second set comprises a second alignment layer disposed between the second linear polarizer and the liquid crystal layer and having an alignment direction substantially perpendicular to the second polarization direction.

47. A modulator as claimed in claim 36, wherein each of the pixels of the first set comprises a first alignment layer disposed between the first linear polarizer and the liquid crystal layer and having an alignment direction substantially perpendicular to the first polarization direction, and wherein each of the pixels of the second set comprises a second alignment layer disposed between the second linear polarizer and the liquid crystal layer and having an alignment direction substantially perpendicular to the second polarization direction.

48. A modulator as claimed in claim 20, wherein each of the pixels comprises an alignment layer which is disposed between the polarization adjuster and the liquid crystal layer and has a plurality of regions of different alignment directions.

49. A modulator as claimed in claim 48, wherein the alignment layer has first and second regions of substantially perpendicular alignment directions.

50. A modulator as claimed in claim 20, wherein the liquid crystal layer is arranged to have an axially symmetric alignment.

51. A spatial light modulator comprising:

a liquid crystal layer;

a substrate;

a pixellated polarization adjusting layer disposed between the liquid crystal layer and the substrate, wherein the modulator includes a plurality of pixels operating in the same mode with a portion of the plurality of pixels belonging to a first set for providing light of a first polarization and another portion of the plurality of pixels belonging to a second set for providing light of a second polarization different from the first polarization.