Patent ID: 8701240
Filing Date: 2014-04-22
Classification: G02B,G03B

Abstract:
1. A projection type display device comprising a projection lens for emitting image light incident thereto, the projection lens comprising a lens cleaning mechanism for cleaning a surface of a lens element of the projection lens, the lens cleaning mechanism comprising: a cleaning unit configured to be pressed against and cover a standby area comprising a part of the surface of the lens element other than an image light passing area through which the image light passes, the cleaning unit being rotationally moved along the surface of the lens element to slide over an entirety of the surface of the lens element, including a remaining part of the surface of the lens element and the standby area; a drive unit connected to a holding member; a control unit configured to rotationally move the cleaning unit by driving the drive unit when the control unit receives a cleaning signal; and an operating unit configured to be operated to input the cleaning signal to the control unit, wherein the lens cleaning mechanism performs a cleaning operation by the control unit rotationally moving the cleaning unit such that the cleaning unit passes over the image light passing area, wherein, during a standby state while waiting for the cleaning operation to be performed, the control unit places the cleaning unit at a first position at which the cleaning unit covers the standby area, wherein the projection lens further comprises a rotationally operable holding frame holding the lens element and the cleaning unit, and wherein, during the standby state, the control unit places the cleaning unit at the first position by using detected values corresponding to a rotational position of the holding frame and a rotational position of the cleaning unit.