Spatial light modulator and display device

• US 20050111072A1
• Filed: 11/23/2004
• Published: 05/26/2005
• Est. Priority Date: 11/25/2003
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Takaura, Atsushi, Fujita, Kazuhiro, Miyagaki, Kazuya, Sugimoto, Hiroyuki, Osaka, Takanobu, Takiguchi, Yasuyuki
• Granted Patent: US 7,336,411 B2
• Time in Patent Office: Days
• US Class Current: 359/279
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02F 1/133365 Cells in which the active layer comprises a liquid crystalline polymer
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/133711 by organic films, e.g. polymeric films
• CPC Class Codes: G02F 1/141 using ferroelectric liquid crystals
• CPC Class Codes: G02F 1/1418 using smectic liquid crystals, e.g. based on the electroclinic effect
• CPC Class Codes: G02F 2203/12 spatial light modulator
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 9/3102 using two-dimensional electronic spatial light modulators micromechanical modulators as such G02B26/0833; liquid crystal modulators as such G02F1/13

Abstract

A spatial light modulator is disclosed that can be fabricated easily and is able to prevent degradation of a contrast ratio by suppressing a fringe effect. The spatial light modulator includes a light transmission substrate, a liquid crystal layer, a pixel array, and a phase difference generation unit provided between the light transmission substrate and the liquid crystal layer. A lens array is formed on the light transmission substrate, and the lens array has the same pitch as that of the pixel array.

Claims

1. A spatial light modulation device, comprising:

a light transmission substrate;

a liquid crystal layer;

a pixel array; and

a phase difference generation unit provided between the light transmission substrate and the liquid crystal layer.

2. The spatial light modulation device as claimed in claim 1, wherein

the pixel array includes a plurality of pixel electrodes arranged as a matrix;

a lens array is formed on the light transmission substrate, said lens array having a pitch corresponding to a pitch of the pixel electrode matrix; and

the phase difference generation unit is provided between the lens array and the liquid crystal layer.

3. The spatial light modulation device as claimed in claim 1, wherein

a lens array is formed in the light transmission substrate or on a surface of the light transmission substrate;

the pixel array includes a plurality of pixel electrodes arranged as an array having a pitch corresponding to a pitch of the lens array;

the liquid crystal layer is provided between the light transmission substrate and a pixel array substrate with the pixel array formed thereon; and

the phase difference generation unit is provided between the lens array and the liquid crystal layer with a fixed alignment.

4. The spatial light modulation device as claimed in claim 3, wherein the phase difference generation unit includes a polymer liquid crystal film with a fixed alignment obtained by cooling an aligned polymer liquid crystal film to a glass state.

5. The spatial light modulation device as claimed in claim 3, wherein the phase difference generation unit comprises an aligned liquid crystal polymerized film or cross-linked film having a polymerized group.

6. The spatial light modulation device as claimed in claim 3, wherein the phase difference generation unit comprises a crystal film of an aligned lyotropic liquid crystal.

7. The spatial light modulation device as claimed in claim 3, wherein a surface of the light transmission substrate and a surface of the pixel array substrate adjacent to the phase difference generation unit are processed by liquid crystal alignment treatment.

8. The spatial light modulation device as claimed in claim 3, wherein the phase difference generation unit is formed by transferring a film on another substrate to the light transmission substrate.

9. The spatial light modulation device as claimed in claim 3, wherein a transparent electrode is formed on the light transmission substrate for applying a voltage to the liquid crystal layer through the phase difference generation unit.

10. The spatial light modulation device as claimed in claim 9, wherein the phase difference generation unit is processed by alignment treatment for aligning the liquid crystal layer.

11. The spatial light modulation device as claimed in claim 3, wherein a light transmission interlayer is provided between the liquid crystal layer and the phase difference generation unit.

12. The spatial light modulation device as claimed in claim 11, wherein a side of the light transmission interlayer adjacent to the liquid crystal layer is processed by alignment treatment for aligning the liquid crystal layer.

13. The spatial light modulation device as claimed in claim 11, wherein the light transmission interlayer is a transparent electrode, and a side of the light transmission interlayer adjacent to the liquid crystal layer is processed by alignment treatment for aligning the liquid crystal layer.

14. The spatial light modulation device as claimed in claim 3, wherein each of the pixel electrodes is formed from a light-reflecting material.

15. The spatial light modulation device as claimed in claim 3, wherein the phase difference generation unit includes a λ

/4 wave plate.

16. The spatial light modulation device as claimed in claim 3, wherein the phase difference generation unit generates phase difference for compensating for a residual phase difference in an ON state or OFF state of the liquid crystal layer.

17. The spatial light modulation device as claimed in claim 1, wherein an alignment of the phase difference generation unit is adjustable by applying an external electric field, and the alignment of the phase difference generation unit is fixed after being adjusted.

18. The spatial light modulation device as claimed in claim 17, wherein the phase difference generation unit includes a liquid crystal alignment control film and a curable liquid crystal layer, an alignment of said liquid crystal alignment control film being adjustable in a plane including the liquid crystal alignment control film by applying an electric field in a thickness direction of the liquid crystal alignment control film.

19. The spatial light modulation device as claimed in claim 18, wherein

the phase difference generation unit further includes an alignment film;

the liquid crystal alignment control film includes a liquid crystal film of a Smectic A phase and showing an electroniclinic effect; and

the curable liquid crystal layer includes a light-curable liquid crystal layer.

20. The spatial light modulation device as claimed in claim 18, wherein

the phase difference generation unit further includes an alignment film;

the liquid crystal alignment control film includes a ferroelectric liquid crystal film of a polymer stabilized Smectic C phase; and

the curable liquid crystal layer includes a light-curable liquid crystal layer.

21. The spatial light modulation device as claimed in claim 18, wherein the phase difference generation unit does not include an alignment film.

22. The spatial light modulation device as claimed in claim 18, wherein the curable liquid crystal layer includes a light-curable liquid crystal layer having a dielectric anisotropy being substantially zero.

23. The spatial light modulation device as claimed in claim 17, wherein a lens array is formed in the light transmission substrate or on a surface of the light transmission substrate, and is arranged to correspond to the pixel array.

24. A display device, comprising:

a light source that emits illumination light;

an illumination unit that renders the illumination light to irradiate uniformly; and

a spatial light modulation device including a light transmission substrate, a liquid crystal layer, a pixel array, and a phase difference generation unit provided between the light transmission substrate and the liquid crystal layer.

25. A display device, comprising:

a light source that emits illumination light;

an illumination unit that renders the illumination light from the light source to irradiate uniformly;

a polarized-light splitting unit; and

a spatial light modulation device including a light transmission substrate, a liquid crystal layer, a pixel array, and a phase difference generation unit provided between the light transmission substrate and the liquid crystal layer.

26. A display device, comprising:

a light source that emits illumination light;

an illumination unit that renders the illumination light to irradiate uniformly;

a polarized-light splitting unit;

a spatial light modulation unit that includes a plurality of spatial light modulation elements for forming an image with a pixel array, a lens array arranged to correspond to the pixel array, and a phase difference generation member; and

a pixel shift element;

wherein the phase difference generation member is provided between the lens array and the spatial light modulation elements.

27. The display device as claimed in claim 26, wherein the polarized-light splitting unit includes a polarized-light splitter, and the phase difference generation member includes a λ

/4 wave plate.

28. The display device as claimed in claim 26, wherein the polarized-light splitting unit includes a wire grid polarizer.

29. The display device as claimed in claim 26, wherein the spatial light modulation unit comprises a light transmission substrate, a liquid crystal layer, and a reflection pixel array.

30. The display device as claimed in claim 26, wherein the spatial light modulation elements, the lens array, and the phase difference generation member are formed integrally.

31. The display device as claimed in claim 30, wherein the spatial light modulation unit further includes a reflection liquid crystal displaying element including a lens array substrate, a lower substrate having a reflection pixel array, and a liquid crystal layer between the lens array substrate and the lower substrate;

and

the phase difference generation member is formed on a side of the lens array substrate facing the liquid crystal layer by oblique evaporation.

32. The display device as claimed in claim 30, wherein the spatial light modulation unit further includes a reflection liquid crystal displaying element including a lens array substrate, a lower substrate having a reflection pixel array, and a liquid crystal layer between the lens array substrate and the lower substrate;

and

the phase difference generation member is formed on a side of the lens array substrate facing the liquid crystal layer by structural birefringence.

33. A display device, comprising:

a light source that emits illumination light;

an illumination unit that renders the illumination light to irradiate uniformly;

a polarized-light splitting unit; and

a spatial light modulation unit that includes a light transmission substrate, a liquid crystal layer, a pixel array, and a phase difference generation unit provided between the light transmission substrate and the liquid crystal layer;

wherein

a lens array is formed in the light transmission substrate or on a surface of the light transmission substrate,

the pixel array includes a plurality of pixel electrodes arranged as an array having a pitch corresponding to a pitch of the lens array,

the liquid crystal layer is provided between the light transmission substrate and a pixel array substrate with the pixel array formed thereon, and

the phase difference generation unit is provided between the lens array and the liquid crystal layer with a fixed alignment.

34. The display device as claimed in claim 33, further comprising:

a pixel shift element provided in a light path outgoing from the spatial light modulation unit for shifting or bending the light path so as to display images including pixels downsized by the lens array while changing displaying positions of the pixels with time.

35. A projection display apparatus, comprising:

a display device that displays an image; and

a projecting lens that projects the image;

wherein

the display device includes a light source that emits illumination light;

an illumination unit that renders the illumination light to irradiate uniformly; and

a spatial light modulation device including a light transmission substrate, a liquid crystal layer, a pixel array, and a phase difference generation unit provided between the light transmission substrate and the liquid crystal layer.

36. A projection display apparatus, comprising:

a display device that displays an image; and

a projecting lens that projects the image;

wherein the display device includes a light source that emits illumination light;

an illumination unit that renders the illumination light to irradiate uniformly;

a polarized-light splitting unit;

a spatial light modulation unit that includes a plurality of spatial light modulation elements for forming an image with a pixel array, a lens array arranged to correspond to the pixel array, and a phase difference generation member provided between the lens array and the spatial light modulation elements; and

a pixel shift element.