| 摘要 |
A varifocal lens including a cam cylinder rotatably mounted on a stationary housing, and lenses held in lens barrels slideably positioned within the stationary housing to vary the focal length of the varifocal lens. Cam followers to position the lens barrels extend from the lens barrels to guide grooves in the stationary housing and cam grooves in the cam cylinders. The sliding surfaces of the lens barrels and the cam followers are provided with a layer of resilient material having a low coefficient of friction. The dimensions of the lens barrel sliding surfaces and the cam followers are made larger than the dimensions of the members which they contact, so that the resilient material will be slightly deformed and thereby take up the play between the lens barrels and cam followers and their respective coacting members.
|
