| 摘要 |
PROBLEM TO BE SOLVED: To provide a microscope which is free of defocusing and can properly offset its focus position even when an observation is made with visible light by using an infrared light as the light source of an automatic focusing optical system. SOLUTION: The infrared light emitted by the light source 13 is made incident on an objective lens 2 and imaged on a body 24 to be detected. Reflected light from its surface to be detected 23 travels reverse along the optical path and passes through the objective lens 2 to impinge on a beam splitter 17. On optical detectors 18 and 19, split light spots 37 and 38 are formed respectively. Thus, the amplification factors of amplifiers 29, 30, 31 and 32 are varied to shift the position of a sample in one optical-axis direction where a focus error signal becomes 0. Namely, even when the infrared light is used as the light source of the automatic focusing optical system, the sample surface can be observed in an in-focus state with visible light. |
