Patent ID: 8773599

Claim:
A head mounted display (“HMD”) for displaying computer generated image (“CGI”) light to a user, the HMD comprising: a frame assembly to support the HMD for wearing on a head of the user; an eyepiece secured to the frame assembly and positioned to form a see-through display, the eyepiece including: an optically transmissive substrate; and a repeating pattern of diffraction elements disposed across a viewing region of the optically transmissive substrate, wherein the repeating pattern of diffraction elements is a reflective diffraction grating that both bends the CGI light and focuses the CGI light with magnification, wherein the repeating pattern of diffraction elements is a two-dimensional (“2D”) pattern of three-dimensional (“3D”) diffraction elements, and wherein the 2D pattern repeats horizontally and vertically across the viewing region; and a light engine mounted to the frame assembly and oriented to illuminate the reflective diffraction grating with the CGI light.