Here's Apple's Summary of the Invention: "A head-mounted display may contain a display system and an optical system in a house. The display system may have a pixel array that produces light associated with images. The display system may also have a linear polarizer through which light from the pixel array passes and a quarter wave plate as the light passes after passing through the quarter wave plate. "The optical system may be a cathadioptric optical system having one or more lens elements. The objective elements may include a plano-convex lens and a planar concave lens. A partially reflecting mirror may be formed on a convex surface of the plano-convex lens. A reflective polarizer may be formed on the planar surface of the plano-convex lens or concave surface of the plano-concave lens. An additional quarter wave plate may lie between the reflective polarizer and the partially reflecting mirror. "
Of course, Apple files for ̵