Patent ID: 6710762
Filing Date: 2004-03-23
Classification: G09G

Abstract:
A projection type display having a light valve for modulating and emitting an incident light from a light source, a projection lens for enlarging and projecting an emitted light from the light valve, and a body at least containing the light valve comprising:an intake fan for injecting air into the body; a filter provided on an outside air intake side of the intake fan; a temperature measurement unit having a first temperature detecting device to measure a temperature in the vicinity of the light valve and a second temperature detecting device being arranged in the vicinity of the intake fan to measure a temperature in the vicinity the filter; and a control system to control at least on/off a power supply of the light source based on a temperature measured by the temperature measurement unit; wherein the control system comprises an estimation processing section which measures a temperature difference between the temperature in the vicinity of the light valve and the temperature in the vicinity of the filter based on measurement results of the first temperature detecting device and the second temperature detecting device, and presumes the extent of the dirt of the filter based on the temperature difference.