Projection type display device

TLDR: In this paper, a projection type display device capable of enhancing the brightness of a projected picture when plural light sources are used in the device is presented. But it is not shown how to combine the light beams from different light sources without loss.

Abstract: PROBLEM TO BE SOLVED: To provide a projection type display device capable of enhancing the brightness of a projected picture when plural light sources are used in the device SOLUTION: A light source device 11 is mounted on this projection type display device This light source device 11 is provided with a prism 30 as a light synthesizing means and combines light beams from light sources 1a, 1b by making the light beam from the light source 1a to be made incident on the side 30a of one side forming the apex angle of the prism to be reflected on the side 30b of other side and by making it to be emitted from the bottom side 30c of the prism and, moreover, by making the light beam from the light source 1b to be made incident on the side 30b to be reflected on the side 30a of other side and by making it to be emitted from the bottom side 30c In this case, the prism 30 is made so that angles of incidence θ of the light beams with respect to perpendicular lines of respective sides 30a, 30b are set equal to or smaller than 20° and, moreover, the angle of incidence θ' of the light beam entering from the side 30a to the side 30b is set equal to or larger than the critical angle of about 418° due to the refractive index of the prism Thus, since the light beams of respective lamps 1a, 1b are totally reflected to be combined without loss, the brightness of the projected picture is enhanced COPYRIGHT: (C)2000,JPO