Waveguides
First Claim
1. A projection display comprising a waveguide element into which image bearing light can be injected to propagate along the waveguide element by total internal reflection, the waveguide element including:
- a first layer of material with a first predetermined refractive index and/or first predetermined thickness;
a second layer of material with a second predetermined refractive index and/or second predetermined thickness, at least one of the second predetermined refractive index and the first predetermined thickness being different from the second predetermined refractive index and the second predetermined thickness, respectively;
a grating element arranged on either the first or the second layer of material and arranged to provide beam splitting of image bearing light passing through the grating element and to direct image bearing light propagating along the waveguide element which impinges on the grating element such that the incidence angle of the directed light on the internal surfaces of the waveguide element is greater than the critical angle so that light is output from the waveguide element;
the first and second layers of material are arranged to abut one another such that the grating element is arranged between the first and the second layers of material; and
wherein the first predetermined refractive index and second predetermined refractive index and/or the first predetermined and second predetermined thickness are arranged to vary the spatial periodicity of image bearing light radiated from the waveguide element.
1 Assignment
0 Petitions
Accused Products
Abstract
A projection display (60) includes a first waveguide (64) incorporating a grating structure (74) and second waveguide (66) incorporating an exit grating (84). The first and second waveguides (64, 66) are arrange to expand an image in orthogonal directions. The second waveguide (66) includes a first layer (86) with a first predetermined refractive index and/or first predetermined thickness, a second layer (88) with a second predetermined refractive index and/or second predetermined thickness. The exit grating (84) is arranged to direct at least some impinging light out of the second waveguide(66) and to provide at least some beam splitting of light passing through the exit grating (84). The first and second layers (86, 88) are arranged to abut one another such that the exit grating (84) is therebetween. The first predetermined refractive index and second predetermined refractive index and/or first predetermined thickness and second predetermined thickness are arranged to vary the spatial periodicity of pupils of image bearing light radiated from the second waveguide (66).
139 Citations
21 Claims
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1. A projection display comprising a waveguide element into which image bearing light can be injected to propagate along the waveguide element by total internal reflection, the waveguide element including:
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a first layer of material with a first predetermined refractive index and/or first predetermined thickness; a second layer of material with a second predetermined refractive index and/or second predetermined thickness, at least one of the second predetermined refractive index and the first predetermined thickness being different from the second predetermined refractive index and the second predetermined thickness, respectively; a grating element arranged on either the first or the second layer of material and arranged to provide beam splitting of image bearing light passing through the grating element and to direct image bearing light propagating along the waveguide element which impinges on the grating element such that the incidence angle of the directed light on the internal surfaces of the waveguide element is greater than the critical angle so that light is output from the waveguide element; the first and second layers of material are arranged to abut one another such that the grating element is arranged between the first and the second layers of material; and wherein the first predetermined refractive index and second predetermined refractive index and/or the first predetermined and second predetermined thickness are arranged to vary the spatial periodicity of image bearing light radiated from the waveguide element. - View Dependent Claims (2, 3, 4, 5, 20)
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6. A projection display comprising:
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a first waveguide element arranged to be light transmissive; an image-providing light source device arranged to generate an image and to inject image bearing light into the first waveguide element; a transmission grating associated with the first waveguide element arranged to direct the image bearing light internally along the first waveguide element and through which the image bearing light is outputted from the first waveguide element; a second waveguide element arranged to be light transmissive and transparent that includes a coupling grating arranged to receive the image bearing light from the first waveguide element and to direct the image bearing light along the second waveguide element; the second waveguide element further includes an exit grating arranged to diffract received image bearing light out of the second waveguide element towards an observer; and wherein the second waveguide element includes a first layer of material with a first predetermined refractive index and/or first predetermined thickness, a second layer of material with a second predetermined refractive index and/or second predetermined thickness, the exit grating is arranged on either the first or the second layer of material and arranged to direct at least some impinging image bearing light out of the second waveguide element and to provide at least some beam splitting of image bearing light passing through the exit grating, the first and second layers of material are arranged to abut one another such that the exit grating is arranged between the first and the second layers of material and wherein the first predetermined refractive index and second predetermined refractive index and/or first predetermined thickness and second predetermined thickness are arranged to vary the spatial periodicity of pupils of image bearing light radiated from the second waveguide element. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21)
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Specification