Abstract: A microinterferometer applies low coherent measurement light, which travels along an optical axis in a converging manner, to a front surface of a flange. A part of the measurement light is reflected inside an interferometric optical system, and becomes reference light. Apart of the measurement light passed through the interferometric optical system is reflected from the front surface of the flange, and is incident again upon the interferometric optical system. By combining the reflected light with the reference light, interference light is obtained. While a sample rotating stage rotates a sample lens through 360 degrees, a first imaging camera having one-dimensional image sensor captures 3600 images of the interference light, i.e., the image of the interference light is captured every time the sample lens is rotated by 0.1 degrees. Based on the images of interference fringes, the shape of the front surface of the flange is analyzed.

Abstract: An aspheric surface measuring apparatus includes a sample holder mechanism and an interferential optical mechanism, and performs optical interferometric measurement while rotating a sample every time a measurement angle is varied. The sample holder mechanism has a first air spindle for rotating the sample about a test surface axis and a first airslide. The first airslide carries the sample orthogonally or parallel to the test surface axis. The interference optical mechanism has an interference optical system, a first imaging system, and a second imaging system, a second air spindle, and a second airslide. The second spindle revolves or turns the interference optical system and the first and second imaging systems integrally to change a measurement angle between the measurement optical axis and the test surface axis. The second airslide carries the second air spindle orthogonally to the moving direction of the first airslide.

Abstract: A process of measuring a shape while changing the relative posture of an microscopic interferometer to a sample lens which is rotated about a rotation axis is divided into a process of measuring a top surface in a state where the sample lens is supported from a back surface and a process of measuring a back surface in a state where the sample lens is supported from the top surface. By combining first shape information of a flange side surface acquired by the process of measuring the top surface and second shape information of the flange side surface acquired by the process of measuring the back surface, the relative positional relation between the sample top surface and the sample back surface is calculated.

Abstract: During an initial setting period, if there is a tendency for a belt to move sideways due to tolerance when components are assembled in the initial setting, inclination in the axial direction of a driven roller can be changed after the components are assembled, to adjust degree of tension at both end portions in the transverse direction of the belt wound at a driven roller. Accordingly, the tendency for the belt to move sideways caused during assembly of the components can be corrected. Further, when there are changes over time (reduced elasticity of the belt, changes in the positioned state of rollers, or the like), sideways movement may occur during operation. However, in these cases, since a tapered auxiliary roller is attached at each of end portions in the axial direction of the rollers so as to be able to rotate relatively to the respective roller that is the base body thereof, when the belt moves sideways onto the auxiliary rollers the belt can be promptly returned to its original position.