| 摘要 |
PROBLEM TO BE SOLVED: To adjust focusing with high precision over the whole projection area on a screen. SOLUTION: An all white image with maximum luminance is displayed on a color liquid crystal display unit 2 and projected on the screen 4. A color TV camera 5 picks up the image of the whole projection screen and stores R, G, and B signals in a video memory 6. A dispersion calculation part 7 reads the R, G, and B signals out as to focusing confirmation areas previously set by the center part and peripheral part of the projection screen and calculates dispersion values Rv, Gv, and Bv showing the distribution states of signal levels by image pickup pixels. A liquid crystal angle adjustment part 8 adjusts the angle (swing and tilt) of the liquid crystal surface of the color liquid crystal display unit 2 to the optical axis. A lens position adjustment part 9 moves a projection lens 3 along the optical axis to adjust its focus. A focusing control part 10 controls the liquid crystal angle adjustment part 8 and lens position adjustment part 9 as to the dispersion values Rv, Gv, and Bv of a focusing confirmation area respectively to put the lens in focus uniformly over the entire projection screen. |
