| 摘要 |
PROBLEM TO BE SOLVED: To automatically adjust the focus of a reflection type projector unit, without having optical element, interposed for shutting off the light heading toward a screen from a liquid crystal projector. SOLUTION: This reflection type projector unit projects the image of a reflection type liquid crystal panel to the screen 9, by successively passing a luminous flux via illumination optical system 2 which includes a light source 3 and emits the luminous flux from the light source, a polarization beam splitter 6, the reflection type liquid crystal panel 7 and a projection lens 8 having a focal position varying mechanism 10. The reflection-type projector unit displays the focused image onto the screen, by making the luminous flux reflected by the screen 9 incident on a photodetector 11 again via the projection lens 8 and the polarization beam splitter 6 and causing a focusing control section 12 to drive the focal position varying mechanism 10, according to the signal outputted from the photodetector by the incidence of the reflected luminous flux. |
