Reflective display device and a light source for a display device
First Claim
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1. A display device comprising:
- a spatial light modulator having an optical modulation layer;
a reflector disposed behind the optical modulation layer with respect to a display direction; and
a holographic field lens, wherein for a given angle of incidence, the diffraction efficiency of the holographic field lens varies in a gradient manner over the holographic field lens.
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Accused Products
Abstract
A reflective liquid crystal display device (LCD) (40) includes: a substrate (60), a reflecting layer (61), a liquid crystal layer (62), an electrode layer (63), a color filter layer (64), an upper substrate (65), and a polarizer (66). The reflective liquid crystal display device further includes a holographic field lens (67). By providing the holographic field lens, the LCD can be used with a closely placed, offset light source (41), since the holographic field lens simultaneously concentrates light incident on the LCD and redirects it in a preferred direction. The holographic field lens can be provided within the structure of the LCD.
239 Citations
41 Claims
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1. A display device comprising:
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a spatial light modulator having an optical modulation layer;
a reflector disposed behind the optical modulation layer with respect to a display direction; and
a holographic field lens, wherein for a given angle of incidence, the diffraction efficiency of the holographic field lens varies in a gradient manner over the holographic field lens. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
a first light source emitting light at a first wavelength; and
a second light source emitting light at a second wavelength.
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25. A display device as claimed in claim 24, wherein the first light source comprises a first light emitting diode for emitting light of the first wavelength, and the second light source comprises a second light emitting diode for emitting light of the second wavelength.
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26. A display device as claimed in claim 25,
wherein the holographic field lens is chromatic, and wherein the first and second light sources are disposed at the respective foci of the holographic field lens for the light of the first wavelength and the light of the second wavelength respectively. -
27. A display device as claimed in claim 24,
wherein the holographic field lens is chromatic, and wherein the first and second light sources are disposed at the respective foci of the holographic field lens for the light of the first wavelength and the light of the second wavelength respectively. -
28. A display device as claimed in claim 14, further comprising a cover member, wherein the light source is disposed on the cover member.
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29. A display device as claimed in claim 14, further comprising a support member for supporting the light source.
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30. A display device as claimed in claim 29, wherein the support member is movable between a stowed position and a position in which the light source is able to illuminate the spatial light modulator.
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31. A display device as claimed in claim 1, wherein the optical modulation layer is a liquid crystal layer.
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32. An illumination system for illuminating the display device claimed in claim 1, comprising at least one light source, and a holographic homogenizer disposed in the path of light from said at least one light source.
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33. An illumination system as claimed in claim 32, wherein the holographic homogenizer is a reflective holographic homogenizer.
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34. An illumination system as claimed in claim 32, wherein the holographic homogenizer is a transmissive holographic homogenizer.
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35. An illumination system as claimed in claim 34, further comprising a reflector, wherein the transmissive holographic homogenizer is disposed between said at least one light source and the reflector.
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36. An illumination system as claimed in claim 32, further comprising first, second and third light sources for emitting light at a first wavelength, a second wavelength and a third wavelength, respectively, wherein the first, second and third light sources are disposed in a linear array.
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37. An illumination system as claimed in claim 36, wherein the linear array of light sources is disposed at an achromatic angle to the holographic homogenizer.
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38. An illumination system as claimed in claim 36, wherein each of said at least one light source is a light-emitting diode.
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39. An illumination system as claimed in claim 32, further comprising first, second and third light sources for emitting light of a first wavelength, a second wavelength and a third wavelength respectively, wherein the first, second and third light sources are arranged in a substantially triangular configuration.
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40. An illumination system as claimed in claim 39, wherein each of said at least one light source is a light-emitting diode.
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41. An illumination system as claimed in claim 32, wherein each of said at least one light source is a light-emitting diode.
Specification