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US 4,538,911 AGranted
Three-dimensional interferometric length-measuring apparatus
AssigneeCarl-Zeiss-Stiftung
InventorsErich Heynacher, Reinhard Ludewig
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AssigneeCarl-Zeiss-Stiftung
InventorsErich Heynacher, Reinhard Ludewig
Estimating the term…
The invention relates to a three-dimensional length-measuring device which employs optical interferometry and in which the comparator principle is satisfied as excellently as possible with respect to all three axes. For this purpose, a workpiece holder which is displaceable in orthogonal horizontal directions carries a three-dimensional reflecting body which defines a measurement space and is in the form of three mutually perpendicular adjacent mirrors (triple mirrors). Extensions of measurement beams with which the three-dimensional reflecting body is measured intersect at a point only slightly offset from the workpiece holder, and to obtain high thermal stability, the measurement table and the housing of the measuring device are made of a material of low thermal expansion. In order to determine each coordinate of the position of a movable probe pin with interferometric precision of measurement, a first one of the individual beams of a double-beam flat-mirror interferometer is provided for each coordinate and is directed via a triple prism fixed with respect to the probe-pin holder. The other individual beam of the interferometer is in each case used to directly measure the opposing mirror of the three-dimensional body connected with the workpiece. Interferometer heads themselves are fixedly mounted on the machine. The probe-pin holder which in terms of the optical system need only carry the triple prisms, therefore is of very low weight.
A three-dimensional work-measuring instrument for measuring within a volume defined by a measurement range for each of three orthogonally related directional components, said instrument comprising a work holder and a housing carrying elements of a three-dimensional interferometric displacement-measuring system, said work holder and housing being movable with respect to each other, said elements producing orthogonally related interferometric measurement beams in the three component directions to be measured, a rigid three-dimensional reflecting body secured to the work holder, said body comprising three mirrors in mutually perpendicular relation, each of said mirrors being of area spanning the entire measurement range of a different two of the coordinate directions and oriented to serve as a reflector for a different one of the three interferometric measurement beams.
A three-dimensional work-measuring instrument for measuring within a volume defined by a measurement range for each of three orthogonally related directional components, said instrument comprising a work holder and a housing carrying elements of a three-dimensional interferometric displacement-measuring system, said work holder and housing being movable with respect to each other, said elements producing orthogonally related interferometric measurement beams in the three component directions to be measured, a rigid three-dimensional reflecting body secured to the work holder, said body comprising three mirrors in mutually perpendicular relation, each of said three mirrors being oriented to serve as a reflector for a different one of the three interferometric measurement beams, each one of two of said mirrors extending over the measurement range for a different one of two coordinates while the third one of said mirrors extends over the measurement ranges of said two coordinate directions, a work-contact probe guided by said housing for displacement in the third coordinate direction, and a mirror carried by said probe within said housing, said elements including means within said housing for making an interferometric difference measurement of the third-coordinate distance between the position of the probe and said third mirror.
A three-dimensional work-measuring instrument for measuring within a volume defined by a measurement range for each of three orthogonally related directional components, said instrument comprising a work holder and a housing carrying elements of a three-dimensional interferometric displacement-measuring system, said work holder and housing being movable with respect to each other, said elements producing orthogonally related interferometric measurement beams in the three component directions to be measured, a rigid three-dimensional reflecting body secured to the work holder, said body comprising three mirrors in mutually perpendicular relation, each of said three mirrors being oriented to serve as a reflector for a different one of the three interferometric measurement beams, each one of two of said mirrors extending over the measurement range for a different one of two coordinates while the third one of said mirrors extends over the measurement ranges of said two coordinate directions, a probe-pin holder supported for movement with respect to said housing in at least one of said coordinate directions, at least one of the interferometric measurement beams consisting of two individual beams (107-108), and a mirror system carried by said probe-pin holder and oriented in the path of one of said two individual beams for reversing the direction thereof.
Dependencies are inferred from the claim text.