COMPACT HOLOGRAPHIC ILLUMINATION DEVICE
First Claim
1. An illumination device comprising in series:
- first and second light sources;
a condenser lens; and
a grating device,wherein said grating device comprises at least one Bragg grating;
a light input port and a light output port,wherein said condenser lens directs light from said first and second sources into said input port at first and second incidence angles respectively,wherein said grating device is operative to diffract light from said first and second sources out of said output port into a common direction.
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Accused Products
Abstract
There is provided a colour sequential illumination device comprising in series: first and second light sources; a condenser lens; and a grating device. The grating device comprises at least one Bragg grating. The condenser lens directs light from the first and second sources into the grating device at first and second incidence angles respectively. The grating device diffracts light from the first and second sources into a common direction. Desirably, the Bragg gratings are Electrically Switchable Bragg Gratings. In one embodiment of the invention the light sources are Light Emitting Diodes. Alternatively lasers may be used.
115 Citations
32 Claims
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1. An illumination device comprising in series:
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first and second light sources; a condenser lens; and a grating device, wherein said grating device comprises at least one Bragg grating;
a light input port and a light output port,wherein said condenser lens directs light from said first and second sources into said input port at first and second incidence angles respectively, wherein said grating device is operative to diffract light from said first and second sources out of said output port into a common direction. - 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)
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26. An illumination device comprising:
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a first light source characterised by a first wavelength; a second light source characterised by said first wavelength; a collimating lens; and a first Bragg grating formed by means of a first recording beam incident normal to said grating and a second recording beam incident at an angle to said grating; wherein said lens collimates and directs light from said first light source towards said grating at a first angle; wherein said lens collimates and directs light from said second light source towards said grating at a second angle; wherein said second angle is substantially equal the incidence angle of said second recording beam, wherein said grating has a maximum acceptance angle for light beams whose average direction corresponds to that of said first recording beam, wherein said maximum acceptance angle is defined by the angle at which the diffraction efficiency of said grating falls to a predetermined value. wherein said first angle is greater than said maximum acceptance angle, wherein the normal to said grating defines an illumination axis, and wherein first grating diffracts said second angle light along said illumination axis. - View Dependent Claims (27, 28, 29, 30, 31, 32)
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Specification