| 摘要 |
An apparatus for observing an object comprises an illumination optical system for illuminating an object to be observed with visible light, an observing optical system for observing the object positioned within a visual field illuminated by the illumination optical system, an index projecting optical system for projecting index for focus, the optical system having projecting luminous flux of wavelength at least a part of which is common with the wavelength of illumination luminous flux of the illuminating optical system, device for restricting luminous flux of index by intermittently projecting index light from the index projecting optical system, each projecting time being set so that no photogene occur in an examiner's eye, device for restricting luminous flux of illumination by intermittently conducting illumination by the illuminating optical system when index projection is not conducted, and by restricting the time of not conducting illumination to a time not recognized by the examiner, and device for detecting an image of focus index projected on the object, wherein relative distance of the object with respect to the focus index is changed based on the results detected by the detecting device.
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