Patent ID: 6980360

Claim:
A focus stabilizing apparatus comprising: an objective lens arranged underneath an observation sample so as to face the observation sample; a fixing base; a sample base on which the observation sample is placed; a focus adjusting mechanism, which continuously extends between the sample base and the fixing base and surrounds the objective lens, for varying a distance along an optical axis of the objective lens between the sample base and the fixing base; a minute movement table to which the objective lens is fixed; parallel springs situated between the fixing base and the minute movement table to allow the minute movement table to be moved in an optical axis direction of the objective lens; an actuator provided between the fixing base and the minute movement table to minutely displace the minute movement table in the optical axis direction of the objective lens; a displacement sensor provided between the fixing base and the minute movement table for detecting a displacement amount of the objective lens; and a controller which allows the actuator to perform an extending/contracting operation based on a detection output of the displacement sensor to control the objective lens and bring the objective lens to a just-in-focus position relative to the observation sample.