Patent ID: 7443513

Claim:
Apparatus for optical measurement of an object ( 1 ), comprising an interferometer for measuring movements along an axis (A) of a measurement beam ( 3 ) which passes through the interferometer, a microscope with an objective ( 12 ) and a focusing device ( 18 ), the focusing device ( 18 ) changes a relative position of the object ( 1 ) and a focal point of the objective ( 12 ) relative to each other in response to signals from a focus controller, the interferometer and the microscope are located relative to each other such that the measurement beam ( 3 ) which passes through the interferometer is projected over a beam path of the microscope onto the object ( 1 ), the microscope comprises a confocal auto-focus microscope which includes the focus controller ( 17 ), a focus detector ( 8 ), a light source for generating a focusing beam, and a spatial filter ( 11 ), which is arranged in the beam path of the confocal auto-focus microscope, such that the filter essentially suppresses non-focal beams, which are incident on the objective ( 12 ) from points outside of the focal point of the objective ( 12 ), the focusing beam is generated by a light source projected over the objective ( 12 ) onto the object ( 1 ) and onto a focus detector ( 8 ), and the focus controller ( 17 ) communicates with the focusing device ( 18 ) and the focus detector ( 8 ) such that the focus detector ( 8 ) outputs measurement signals to the focus controller ( 17 ) and the focus controller ( 17 ) controls the focusing device ( 18 ) depending on the measurement signals such that a measurement point of the object ( 1 ) comes to lie at the focal point of the objective ( 12 ), and the focusing beam is formed by light which passes through the interferometer.