A system is provided for removing extraneous side images produced by light emitted at high angles from a display in a head mounted display (HMD), which results in light rays traveling along undesired paths that bounce one or three times from a worldside surface of a lightguide in the HMD, instead of the two bounces along the path taken by the light that forms the primary image. The system includes an optical element that couples the display to a prism to provide light to a lightguide in the HMD. The optical element is fabricated to include a V-shaped groove. Light incident upon the V-shaped groove at relatively high angles, e.g., light traveling along paths that would bounce one or three times in the lightguide, is totally internally reflected out of the path that couples the light into the HMD lightguide.
Cakmakci, Ozan; Dunphy, James; and Martinez, Oscar, "TOTAL INTERNAL REFLECTION BASED ANGLE FILTER FOR SIDE IMAGE MITIGATION IN A CURVED LIGHTGUIDE", Technical Disclosure Commons, (November 15, 2017)