LIGHT TRANSMITTING PLATE AND SURFACE LIGHT SOURCE DEVICE USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a transparent light transmitting plate of good optical efficiency and optimum as a back light device for a liquid crystal display or the like and also provide a surface light source device using the light transmitting plate. SOLUTION: A large number of minute protuberances having a saw tooth cross section with respective saw tooth angles θ being approximately the same are formed at substantially equal intervals on the bottom of a transparent light transmitting plate 1 having its lateral cross section formed in a wedge shape and it is made in a composition to radiate uniform luminance light from the whole surface of an outgoing light surface 2 facing the minute protuberances by utilizing internal reflection of a minute total reflection surface 3, which is provided on respective bottoms of the minute protuberances.