US Patent 10571698 Light guide device and display apparatus

A light guide device used in a display apparatus includes a transparent light guide portion that guides light beams incident from one end side to a light-emitting portion. The light guide portion includes a plurality of partial reflection surfaces between a first surface and a second surface which are parallel to each other, the plurality of partial reflection surfaces being inclined at the same angle from a normal direction with respect to the second surface toward the one end side. In the plurality of partial reflection surfaces, an appropriate incident angle range of the partial reflection surface positioned on the one end side is set to a larger angle than that of the partial reflection surface positioned on another end side.