摘要 |
A hollow light guide with opposed first and second parallel sections having confocal, parabolic cross-sectional shape. The light guide may be a prism light guide, or other hollow light guide such as a metallic mirror light guide or a multi-layer dielectric light guide. The cross-sectional shapes have vertices separated by a distance which does not exceed about three times (preferably, about 2.5 times) the focal length of the shapes.
|