Patent ID: 8672484

Claim:
A projection display device, comprising: a light source unit configured to emit a light; a first lens including a light incidence surface having a curvature smaller than a curvature of a light outgoing surface of the first lens, the first lens configured to convert the light received from the light source into a condensed light; a second lens configured to receive the light from the first lens, and to convert the received light into a collimated light, the second lens having a refractive index lower than a refractive index of the first lens; an optical element configured to selectively transmit or reflect the collimated light from the second lens; and an image projection unit configured to project an image onto an external screen, wherein the first lens converts the light received from the light source into a condensed light having rays that are substantially parallel or substantially converged such that a size of the image through the second lens is equal to or smaller than a size of an image through the first lens.