METHOD AND APPARATUS FOR QUICK AUTOFOCUS OF OBJECT IMAGE

摘要

PURPOSE: To allow the focusing of an object capable of changing its position along an optical axis to adapt to a quick change of the object position by adjusting the position of an image formation unit on a position in image space where an image is focused on its image face. CONSTITUTION: A system to be automatically controlled comprises a detector 5 for determining and measuring the distance of an object 1 from a lens 11 and an actuator 9 for positioning the image formation unit 13 on an image face for an image 19. A controller 7 receives data from the detector 5 and determines a necessary controlled variable to be impressed to the actuator 9 to rearrange the unit 13 on a new image face generated due to a change in the position of the object 1. A distance measuring instrument 15 for monitoing the position of the unit 13, supplying the monitored information to the controller 7 and presenting a control feedback loop to the actuator 9 is connected between the lens 11 and the unit 13. In addition to the supply of the positional data of the unit 13, the instrument 15 supplies a feedback signal to the controller 7 to maintain the unit 13 on the image face.