# US 11,307,432 B2 · Waveguide laser illuminator incorporating a Despeckler > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,307,432 B2 - Document ID: US11307432B2 - Status: Granted - Kind: B2 - Application number: 17/214,362 - Filed: 2021-03-26 - Published: 2021-11-11 - Granted: 2022-04-19 - Earliest claimed: 2014-08-08 - Assignees: DigiLens Inc. - Applicants: DigiLens Inc. - Inventors: Milan Momcilo Popovich; Jonathan David Waldern; Alastair John Grant - Web page: https://patentgrep.com/patent/US11307432B2 ## CPC - G02B 27/48: Laser speckle optics - G02B 5/32: Holograms used as optical elements - G02B 6/0016: {Grooves, prisms, gratings, scattering particles or rough surfaces} - G02B 6/0038: {Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide} - G02B 6/0055: {Reflecting element, sheet or layer} - G02B 6/0083: {Details of electrical connections of light sources to drivers, circuit boards, or the like} - G02B 27/4261: {having a diffractive element with major polarization dependent properties} - G02F 1/292: {by controlled diffraction or phased-array beam steering (controlled diffraction for optical switching G02F1/31)} - G02F 1/3136: {of interferometric switch type} - G02B 6/0035: {provided on the surface of the light guide or in the bulk of it} - G02B 6/0066: {characterised by the light source being coupled to the light guide} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract There is provided an illumination device comprising: a laser; a waveguide comprising at least first and second transparent lamina; a first grating device for coupling light from the laser into a TIR path in the waveguide; a second grating device for coupling light from the TIR path out of the waveguide; and a third grating device for applying a variation of at least one of beam deflection, phase retardation or polarization rotation across the wavefronts of the TIR light. The first second and third grating devices are each sandwiched by transparent lamina. ## Claims ### Claim 1 An image projection device comprising: a light source; a reflective microdisplay; a waveguide comprising: an input grating for coupling light from said light source into a total internal reflection (TIR) path in said waveguide; and an output grating for coupling light from said TIR path out of said waveguide and towards said reflective microdisplay, wherein said waveguide is formed from transparent lamina sandwiching said input grating and said output grating, wherein said output grating is configured to transmit light reflected from said reflective microdisplay; and a lens for projecting image modulated light reflected from said microdisplay over a field of view. ### Claim 2 (depends on 1) The image projection device of claim 1, wherein said light source is configured to emit light in at least first and second wavelength bands; and wherein said input grating and said output grating have high diffraction efficiency for light in said first and second wavelength bands. ### Claim 3 (depends on 1) The image projection device of claim 1, wherein said output grating has at least one characteristic for providing uniform illumination onto said microdisplay selected from the group of optical power, diffusion, spatially varying light cone tilt, spatially varying light cone angle and spatially varying refractive index modulation. ### Claim 4 (depends on 1) The image projection device of claim 1, further comprising a grating device for applying a variation of at least one of beam deflection or phase retardation across wavefronts of said light coupled into the TIR path, wherein said grating device is sandwiched by said transparent lamina. ### Claim 5 (depends on 4) The image projection device of claim 4, further comprising transparent electrodes applied to said transparent lamina. ### Claim 6 (depends on 4) The image projection device of claim 4, wherein said grating device has an optical prescription that varies along said waveguide. ### Claim 7 (depends on 4) The image projection device of claim 4, wherein said grating device comprises more than one grating lamina adjacently disposed along said waveguide. ### Claim 8 (depends on 4) The image projection device of claim 4, wherein said grating device comprises a two-dimensional array of switchable grating elements, wherein electrodes are applied to overlapping portions of the transparent lamina sandwiching said switchable grating elements, at least one of said electrodes being pixelated into elements substantially overlapping said switchable grating elements. ### Claim 9 (depends on 4) The image projection device of claim 4, wherein said grating device is disposed along the TIR path between said input grating and said output grating. ### Claim 10 (depends on 1) The illumination device of claim 1, wherein said grating device diffuses light into the direction of said TIR path. ### Claim 11 (depends on 1) The image projection device of claim 1, further comprising a second grating device for applying variation of at least one of beam deflection or phase retardation across the wavefronts of said light couple into the TIR path, wherein said grating devices overlap, have identical prescriptions, and are reciprocally configured. ### Claim 12 (depends on 1) The image projection device of claim 1, wherein said grating device is configured as a Hadamard array. ### Claim 13 (depends on 4) The image projection device of claim 4, wherein said grating device provides a laser despeckler. ### Claim 14 (depends on 1) The image projection device of claim 1, wherein said light source comprises at least one laser emitter providing at least one wavelength. ### Claim 15 (depends on 4) The image projection device of claim 4, wherein at least one said transparent lamina is fabricated from plastic. ### Claim 16 (depends on 1) The image projection device of claim 1, wherein said lens collimates said image modulated light. ### Claim 17 (depends on 1) The image projection device of claim 1, wherein said output grating incorporates an optical prescription of at least one selected from the group of a microlens and a diffuser. ### Claim 18 (depends on 1) The image projection device of claim 1, wherein said waveguide supports at least one selected from the group of a randomly scattering surface structure, a mirror, a reflection grating, a transmission grating, a blazed surface relief grating, a polarization rotation layer and a reflector overlapping said grating device. ### Claim 19 (depends on 1) The image projection device of claim 1, wherein said waveguide is terminated at an end thereof by at least one selected from the group of a reflector and a quarter wavelength retarder.