Invention Grant
- Patent Title: Reducing stray light transmission in near eye display using resonant grating filter
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Application No.: US14878727Application Date: 2015-10-08
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Publication No.: US10241332B2Publication Date: 2019-03-26
- Inventor: Tuomas Vallius
- Applicant: Microsoft Technology Licensing, LLC
- Applicant Address: US WA Redmond
- Assignee: MICROSOFT TECHNOLOGY LICENSING, LLC
- Current Assignee: MICROSOFT TECHNOLOGY LICENSING, LLC
- Current Assignee Address: US WA Redmond
- Agency: Mayer & Williams PC
- Agent Mark K. Young
- Main IPC: G02B27/01
- IPC: G02B27/01 ; G02B6/124 ; G02B6/34 ; G02B27/00 ; G02B5/18 ; F21V8/00 ; G02B27/42 ; G02B6/122 ; G02B27/10 ; G02B6/00

Abstract:
A near eye optical display system comprising a waveguide and diffractive optical elements (DOEs) for in-coupling, exit pupil expansion, and out-coupling reduces the transmission of stray light in the system using a doubly-periodic surface relief microstructure that combines a guided-mode resonant filter with Bragg reflectance. Such resonant grating filter may be configured with grooves and/or ridges of different widths that are located on the waveguide that have respective sub-periods that match Bragg reflectance periods for particular wavelengths. The interaction of the sub-periods gives rise to a photonic band gap effect in which the resonant grating's effective refractive index is modulated to increase angular sensitivity and wavelength bandwidth of the resonant grating filter. The sub-periods define an overall period (i.e., a super period) for the resonant grating filter by which incident light is coupled into the waveguide, guided, and then coupled out of the waveguide at the side of incidence.
Public/Granted literature
- US20170102544A1 REDUCING STRAY LIGHT TRANSMISSION IN NEAR EYE DISPLAY USING RESONANT GRATING FILTER Public/Granted day:2017-04-13
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