Projection LCD backlighting for improved VR display contrast through a pancake lens while using much less power

Over 80% of the light produced by today’s VR headsets using either emissive (OLED, μLED, etc.) or diffuse-backlit Liquid Crystal Displays (LCD) never directly reaches the user’s eye and therefore represents not only wasted power but also represents the primary scattered light responsible for low contrast through a pancake lens. This paper discloses a simple, relatively compact approach to propagate the light from an array of light sources through the LCD and pancake lens so that an exit pupil is created only large enough for typical headset usage, thereby dramatically reducing the light outside that exit pupil for noticeably increased visual contrast while providing a 65% reduction in power and heat generation.