Efficient backlighting for a portable display

摘要

Efficiency in light transfer between a light source and a viewing screen is attained in the invention by positioning a small diameter source of light at a position of highest light transfer intensity within an essentially semicircular reflector interfacing at the wide portion of a wedge shaped light pipe light transfer member and minimizing reflection losses at every optical interface in the light path between the light source and the viewer. A wedge shaped light pipe light transfer member of the invention has attached a light source with unit diameter light bulb positioned off center of a four unit diameter semicircular solid reflector of a transparent material that is closely index of refraction matched with index of refraction of a wedge shaped light pipe light transfer member on the upper face of which is positioned the addressable viewing screen and, the portion of the wedge shape light pipe light transfer member being terminated in a reflection preventing face that is at about 45 degrees from the centerline of the wedge shaped member.