PROJECTION TYPE DISPLAY DEVICE

摘要

PROBLEM TO BE SOLVED: To reduce cost and to miniaturize a device. SOLUTION: A luminous flux control element 12 consisting of a base member 13 for transmitting light and triangular prisms 14a to 14d is disposed between a light source means 2 and a light valve 3. The prisms 14a to 14d are located at positions where a part of the light transmitted through the prism is emitted in a radial direction within±15 deg. in a peripheral direction of two virtual lines L1 and L2 on the light incident surface of the prism corresponding to respective diagonals on the image surface of the light valve 3 by setting the intersection of the virtual lines L1 and L2 as center O.