Illumination system and display device
First Claim
1. An illumination system comprising:
- a polarized light source for emitting circularly polarized light;
a cholesteric filter having a first region which transmits circularly polarized light of a wavelength falling within a first predetermined band and reflects light having a wavelength falling outside of the first band, and a second region which transmits circularly polarized light of a wavelength falling within a second predetermined band different from the first predetermined band and reflects light having a wavelength falling outside of the second band; and
a reflector for returning the light reflected by the cholesteric filter towards the cholesteric filter, wherein the boundary between the first region and the second region is a plane parallel to a direction of illumination.
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Accused Products
Abstract
An illumination system includes a polarized light source which emits circularly polarized light of a particular handedness and a cholesteric filter having a region arranged to transmit circularly polarized light falling within a first wavelength band and to reflect other wavelengths of circularly polarized light. A reflector redirects the reflected light back towards the cholesteric filter. The cholesteric filter can include a first layer having portions which reflect red, green and blue light while transmitting other colors, and a second layer identical to the first layer but out of alignment therewith so that each region of the filter transmits only one color of light, the other colors being reflected.
74 Citations
32 Claims
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1. An illumination system comprising:
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a polarized light source for emitting circularly polarized light; a cholesteric filter having a first region which transmits circularly polarized light of a wavelength falling within a first predetermined band and reflects light having a wavelength falling outside of the first band, and a second region which transmits circularly polarized light of a wavelength falling within a second predetermined band different from the first predetermined band and reflects light having a wavelength falling outside of the second band; and a reflector for returning the light reflected by the cholesteric filter towards the cholesteric filter, wherein the boundary between the first region and the second region is a plane parallel to a direction of illumination. - 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)
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Specification