Lens shift mechanism and projection image display device

摘要

A central position detection section has a detection width in which the central position has a median value along one axial direction. When the direction from a position, which is located at the time at which returning is started toward the central position is defined as a go direction, the control section commands that a drive mechanism should sequentially perform following operations: a first operation of driving a projection lens assembly in the go direction; a second operation of allowing the projection lens assembly to travel in a return direction at least by the detection width; and a third operation of allowing the projection lens assembly to travel in the detection width in the go direction by ½ of the detection width traveled in the go direction.

主权项

1. A lens shift mechanism for allowing a projection lens assembly to travel in a go and return direction in a certain range in at least one axial direction among axes perpendicular to an optical axis of the projection lens assembly, the lens shift mechanism comprising:
a drive mechanism for driving the projection lens assembly in at least the one axial direction; a control section for controlling the drive mechanism such that the projection lens assembly is returned to a central position in the certain range; and a central position detection section for detecting that the projection lens assembly reaches the central position, wherein the central position detection section has a detection width in which the central position has a median value along the one axial direction, when a direction from a position, which is located at a time point at which returning is started, toward the central position, is defined as a go direction, the control section commands that the driving mechanism should perform following operations: a first operation of allowing the projection lens assembly to travel in the go direction and to pass one end of the detection width and to travel at least the detection width; after the first operation, a second operation of allowing the projection lens assembly to travel in a return direction by at least the detection width; and after the projection lens assembly travels in at least the detection width by the second operation, a third operation of allowing the projection lens assembly to travel in the go direction from one end of the detection width by ½ of the detection width which has been traveled in the go direction.