Patent ID: 7071451
Filing Date: 2006-07-04
Classification: G02B

Abstract:
1. An autofocus system comprising: a light source; a focusing illumination optical system that forms an optical image generated with light from the light source on a target object through an objective lens; a focusing image forming optical system that receives through the objective lens reflected light generated as the optical image is reflected off the target object and forms a reflected image of the optical image; a photoelectric converter that is provided at an image forming position at which the reflected image is formed by the focusing image forming optical system to detect the reflected image; a signal output device that outputs a signal for controlling a focus actuator based upon a signal corresponding to the reflected image obtained at the photoelectric converter; and an image forming position adjustment device that adjusts an offset quantity between a focus position of the objective lens and an image forming position of the optical image by moving at least one of the image forming position of the optical image or the image forming position of the reflected image along an optical axis, wherein the image forming position adjustment device receives light that originated from the light source and comprises a convex lens and a concave lens, the distance between the convex and concave lenses is adjustable, and the image forming position adjustment device is provided on a parallel light flux shared by the focusing illumination optical system and the focusing image forming optical system to move the image forming position of the optical image and the image forming position of the reflected image along the optical axis.