| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a projection type video display device which allows a projection surface to be adjusted at a constant illuminance without influence of variation in characteristics among products such as optical system parts and illuminance sensors, variation with time, and lens shift. <P>SOLUTION: A projection type video display device includes a lens shift device, a position detector which detects a lens shift position, and an illuminance sensor which receives stray light in front of a projection lens for incidence. An initial illuminance table showing the relation between an initial screen illuminance value which is a screen illuminance at a reference projection surface before use of a product and an initial sensor illuminance value which is an illuminance measured with the illuminance sensor, and an illuminance table showing a ratio of screen illuminance at the reference projection surface between when the lens is shifted and when the lens is not shifted are stored. A sensor illuminance target value Y3 is calculated using the tables, for a screen illuminance preset value X2 which is set by a user. The luminosity of the light emitted from the projection lens is adjusted such that the sensor illuminance measured value Y4 approaches the target value. <P>COPYRIGHT: (C)2013,JPO&INPIT |
