Abstract: An interference objective lens includes: an objective lens configured to converge a light to be emitted from a light source toward a measurement target; a reference surface unit having a reference surface; and a beam splitter configured to split the light having passed through the objective lens into a reference optical path facing toward the reference surface and a measurement optical path facing toward the measurement target, to synthesize a reflected light from the reference surface and a reflected light from the measurement target, and to output the same as an interference light, wherein the reference surface unit is configured to be replaceable.

Abstract: An interference objective lens includes: an objective lens configured to converge a light to be emitted from a light source toward a measurement target; a reference surface unit having a reference surface; and a beam splitter configured to split the light having passed through the objective lens into a reference optical path facing toward the reference surface and a measurement optical path facing toward the measurement target, to synthesize a reflected light from the reference surface and a reflected light from the measurement target, and to output the same as an interference light, wherein the reference surface unit is configured to be replaceable.

Abstract: An image measuring device comprises an imaging unit; and an processing unit operative to treat image information obtained at the imaging unit by imaging a measurement object and compute coordinate information on the measurement object from the image information. The processing unit includes an error correcting unit operative to apply the error information inherent in the imaging unit to correct the image information obtained at the imaging unit by imaging the measurement object, thereby obtaining corrected image information, and a coordinate computing unit operative to compute coordinate information on the measurement object from the corrected image information.

Abstract: An interference optical system (18) leads parallel beam to a pair of opposed test surface (M1, M2). It then leads, from the test surfaces via different optical paths (C1, C2), interference fringe images formed by radiation of the parallel beam to the test surfaces (M1, M2), respectively. The interference optical system (18) has a pair of opposite reference surfaces (S1, S2) formed thereon and defined with a highly accuracy parallelism and distance. A measurement head (27) is provided with these reference surfaces (S1, S2), which are interposed between and oppose to the test surfaces (M1, M2), respectively. Imaging devices (19a, 20a) take interference fringe images that are created through interference between a light reflected at each of the test surfaces (M1, M2) and a light reflected at the corresponding reference surface (S1, S2) opposing thereto.

Abstract: An interference optical system (1) is employed to split an input light beam in two, giving a predetermined optical path length difference to the resultant two light beams and thereafter synthesizing them to generate interference fringes. A reference light with a known wavelength &lgr;1 is introduced into the interference optical system (1) from a coherent reference light source (2). A test light with an unknown wavelength &lgr;2 is simultaneously introduced into the interference optical system (1) from a coherent test light source (3) via a different optical path. The interference optical system (1) modulates both received signals obtained from the reference and test lights by giving the same variation to optical path length differences for the reference and test lights. Degrees of modulations of the received signals, obtained from the reference and test lights, depend on their wavelengths &lgr;1 and &lgr;2, respectively.

Abstract: A shape measuring apparatus is provided, which is capable of accurately measuring the shape of an observed surface of an object to be measured and which can be designed to be compact in size and light in weight. An optical reflected image from an observed surface of an object to be measured and an optical reflected image from a reference surface are interfered with each other to generate interference light. The interference light is dispersed into at least three beams, which are shifted in phase by respective predetermined phase shifting amounts. At least three interference fringe images are simultaneously captured by at least one image pickup device which is smaller in number than the interference fringe images.

Abstract: A shape measuring apparatus is provided, which is capable of accurately measuring the shape of an observed surface of an object to be measured and which can be designed to be compact in size and light in weight. An optical reflected image from an observed surface of an object to be measured and an optical reflected image from a reference surface are interfered with each other to generate interference light. The interference light is dispersed into at least three beams, which are shifted in phase by respective predetermined phase shifting amounts. At least three interference fringe images are simultaneously captured by at least one image pickup device which is smaller in number than the interference fringe images.

Abstract: In machining such as lapping and polishing, the detection of interference fringes is carried out during the machining, and an interference fringe image of a size sufficient to determine the surface profile is obtained. The workpiece is mounted on a machining mechanism base, and a lapping tool mounted on the workpiece is rotated. The lapping tool has a measurement window and an interferometer is provided above the workpiece via the lapping tool. The interferometer captures plural interference fringe images at different positions of the measurement window, each including fringe images of the measurement window areas and shadow images of the areas obstructed by the lapping tool. The shadow images are eliminated from the interference fringe images on the basis of the reference value for the optical intensity of the shadow image, and the fringe images of the measurement window areas are synthesized to form consecutive synthesized interference fringe images for a wide range of interference fringes.

Abstract: In a machining device, a workpiece is laid on a working mechanism base and a lapping machine laid on the workpiece is operated to rotate. A lap liquid is supplied between the lapping machine and the workpiece. The lapping machine is provided with a plurality of holes as measurement windows. Above the workpiece, an interferometer is disposed on the opposite side of the lapping machine from the workpiece. The interferometer detects interference fringes on a machined surface of the workpiece through the measurement windows. Based on detection results, the rotation of the lapping machine and the position of the workpiece are controlled.