Microsoft is holding a press conference on February 24 at MWC and it suggests that the company’s next-generation HoloLens might be unveiled there. According to a new patent, Microsoft is considering improvements for diffractive optical elements which is found inside a near-eye display (NED) devices.
First spotted by us, the patent entitled ‘Refractive coating for diffractive optical elements’ was filed by Microsoft in mid-2016 and published by USPTO on February 5, 2019. The patent highlights improvements for a near-eye display (NED) device.
In the patent application’s background section, Microsoft explains AR and VR headsets are advancing to provide users with more immersive visual experiences. Such headsets can generate imagery which is displayed to the user via a transparent display that also allows users to view the physical environment.
This patent describes a technique where the optical waveguide can include a light-transmissive substrate configured for use in a near-eye display (NED) device and it can also come with a diffractive optical element (DOE). The DOE may come with diffraction grating made of a second material having a second refractive index and there is also coating diffraction grating.
“A waveguide configured for use with a near-eye display (NED) device can include a light-transmissive substrate configured to propagate light rays through total internal reflection and a diffractive optical element (DOE) on a surface of the substrate that is configured to input and/or output light rays to and/or from the substrate. According to some embodiments the DOE can include a diffraction grating made of first material having a first refractive index and a coating of a second material over the diffraction grating, the second material having a second refractive index that is not equal to the first refractive index,” Microsoft explains.