Waveguide Diffraction Grating Layout for Wider HMD Color Gamut

The patent applies parameter changes by adjusting the pitch of sub-pixels for different colors (R, G, B) in the diffraction grating. Specifically, the pitch for red sub-pixels is set to 2.0 μm, green sub-pixels to 3.0 μm, and blue sub-pixels to 4.0 μm. This non-uniform pitch adjustment compensates for the different refractive indices of the waveguide material for different wavelengths, thereby reducing chromatic aberration while maintaining the light field display's advantage of eliminating traditional display devices from the user's field of view.

The patent applies local quality by assigning different pitch values to different color sub-pixels within the same diffraction grating structure. Each color region (R, G, B) has its own optimized pitch that is specifically tuned to minimize chromatic aberration for that wavelength. This localized optimization allows the diffraction grating to maintain high light guidance efficiency for all colors while individually compensating for chromatic aberration effects in each color channel.

The patent implements parameter changes by establishing specific pitch values for different sub-pixel colors (2.0 μm for red, 3.0 μm for green, 4.0 μm for blue) based on optical efficiency calculations. These optimized pitches maximize the optical efficiency spectrum for each color while remaining compatible with standard semiconductor manufacturing processes. The design balances manufacturing simplicity with enhanced color gamut by using pitch values that can be achieved through conventional lithography and etching techniques.