Patent ID: 7278745
Filing Date: 2007-10-09
Classification: G03B

Abstract:
1. An apparatus comprising: a light valve adapted to output a first image; a calibration object, positioned adjacent to the light valve, to output a second image; projection optics optically coupled to the light valve to project the first image and optically coupled to the calibration object to project the second image, the projection optics having a first lens element relatively disposed away from the light valve; a temperature sensor, adapted to sense a temperture of the apparatus, and to generate a first sensor signal based at least in part upon the sensed temperture; and a controller adapted to determine a change in focal distance of the projection optics based at least in part upon the sensed temperture, and to generate a control signal based at least in part upon the change in the focal distance for use to adjust the ralative disposition of the first lens element and the light valve.