Surface relief grating in an optical waveguide having a reflecting surface and dielectric layer conforming to the surface
First Claim
1. A display device for displaying an image, the device comprising:
- an optical waveguide arrangement for directing image-bearing light, received from an image source over a range of angles relative to an injection axis, through the optical waveguide arrangement for output to form a viewable image; and
an input grating for diffracting into the optical waveguide arrangement the received image-bearing light such that all of the diffracted light is totally internally reflected within the optical waveguide arrangement and so that image bearing light output from the optical waveguide arrangement has a field of view corresponding to said range of angles,wherein the input grating is a surface relief grating for diffracting light over said range of angles into the optical waveguide arrangement, the input grating having a profiled surface and a layered structure applied thereto comprising a layer of reflective material providing a reflective surface and at least one layer of dielectric material, each of the reflective surface and the at least one layer of dielectric material being conformal in profile with said profiled surface and disposed such that the received image-bearing light interacts with both the at least one layer of dielectric material and the reflective surface, andwherein the thickness of the at least one layer of dielectric material with which the light interacts is configured to control the angular bandwidth of the input grating such that the image bearing light that is incident upon the input grating over said range of angles is diffracted into the optical waveguide arrangement.
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Accused Products
Abstract
The invention relates to a display device for displaying an image over a field of view. The device comprises: an optical arrangement for directing image bearing light from an image source so that the light has rays at a range of angles relative to an injection axis; and an optical waveguide having an input grating for diffracting into the waveguide said light over said range of angles such that all of the diffracted light is totally internally reflected within the waveguide and so that image bearing light output from the waveguide has a field of view corresponding to said range of angles, wherein the input grating is a surface relief grating having a profiled reflective surface and at least one layer of dielectric material conforming to the surface for diffracting light over said range of angles into the waveguide.
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Citations
10 Claims
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1. A display device for displaying an image, the device comprising:
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an optical waveguide arrangement for directing image-bearing light, received from an image source over a range of angles relative to an injection axis, through the optical waveguide arrangement for output to form a viewable image; and an input grating for diffracting into the optical waveguide arrangement the received image-bearing light such that all of the diffracted light is totally internally reflected within the optical waveguide arrangement and so that image bearing light output from the optical waveguide arrangement has a field of view corresponding to said range of angles, wherein the input grating is a surface relief grating for diffracting light over said range of angles into the optical waveguide arrangement, the input grating having a profiled surface and a layered structure applied thereto comprising a layer of reflective material providing a reflective surface and at least one layer of dielectric material, each of the reflective surface and the at least one layer of dielectric material being conformal in profile with said profiled surface and disposed such that the received image-bearing light interacts with both the at least one layer of dielectric material and the reflective surface, and wherein the thickness of the at least one layer of dielectric material with which the light interacts is configured to control the angular bandwidth of the input grating such that the image bearing light that is incident upon the input grating over said range of angles is diffracted into the optical waveguide arrangement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for controlling the angular bandwidth of a surface-relief diffraction grating, having a profiled surface, which when applied to a waveguide is arranged to diffract light received over a range of angles into the waveguide such that the received light may propagate through the waveguide by total internal reflection, the method comprising:
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applying a layered structure to said profiled surface, the layered structure comprising a layer of reflective material providing a reflective surface and at least one layer of dielectric material, each of the reflective surface and the at least one layer of dielectric material being conformal in profile with said profiled surface and disposed such that the received light interacts with both the at least one layer of dielectric material and the reflective surface; and selecting the thickness of the at least one layer of dielectric material with which the light interacts thereby to define the angular bandwidth of the diffraction grating such that the light that is incident upon the diffraction grating over said range of angles is diffracted into the waveguide. - View Dependent Claims (10)
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Specification