US Patent 7315412 Focus stabilizing mechanism for microscopes and similar optical instruments

An optical microscope of high stability such that problems wherein an image of a sample becomes unsharp during observation and movement (drift) of the object point (object) occurs are solved because the defocusing in the Z direction attributable to thermal expansion of the optical microscope is compensated. The optical instruments are characterized as comprising an optical system unit symmetrical to the optical axis in terms of weight and shape and a peripheral unit having a sample positioning mechanism is constituted by combining components having temperature dependences close to zero.