Abstract: A step gauge includes: measurement blocks each having reference measurement surfaces; interval blocks each interposed between a pair of ones of the measurement blocks to keep a distance between the pair of ones of the measurement blocks at a predetermined distance, the measurement blocks and the interval blocks being alternately aligned one by one in one direction. The measurement blocks and the interval blocks each have a coefficient of linear thermal expansion of less than 0.03×10?6(1/K) and have through holes aligned in the one direction. The step gauge further includes a tie rod inserted in the through holes and countersunk screws respectively fixed to ends of the tie rod. The tie rod is made of a material having a coefficient of linear thermal expansion of less than 0.5×10?6(1/K).

Abstract: A laser adjustment method includes a first adjustment step and a second adjustment step. In the first adjustment step, using a light detector detecting a second harmonic light, optical intensity and wavelength of the second harmonic light is detected and a first temperature adjuster is adjusted to adjust temperatures of a Nd:YVO4 crystal and a KTP crystal such that the detected wavelength of the second harmonic light approaches a desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value. In the second adjustment step, after the first adjustment step, a temperature of an etalon is adjusted by a second temperature adjuster such that the detected wavelength of the second harmonic light approaches the desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value.

Abstract: A step gauge includes: measurement blocks each having reference measurement surfaces; interval blocks each interposed between a pair of ones of the measurement blocks to keep a distance between the pair of ones of the measurement blocks at a predetermined distance, the measurement blocks and the interval blocks being alternately aligned one by one in one direction. The measurement blocks and the interval blocks each have a coefficient of linear thermal expansion of less than 0.03×10?6(1/K) and have through holes aligned in the one direction. The step gauge further includes a tie rod inserted in the through holes and countersunk screws respectively fixed to ends of the tie rod. The tie rod is made of a material having a coefficient of linear thermal expansion of less than 0.5×10?6(1/K).

Abstract: A laser adjustment method includes a first adjustment step and a second adjustment step. In the first adjustment step, using a light detector detecting a second harmonic light, optical intensity and wavelength of the second harmonic light is detected and a first temperature adjuster is adjusted to adjust temperatures of a Nd:YVO4 crystal and a KTP crystal such that the detected wavelength of the second harmonic light approaches a desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value. In the second adjustment step, after the first adjustment step, a temperature of an etalon is adjusted by a second temperature adjuster such that the detected wavelength of the second harmonic light approaches the desired wavelength and such that the optical intensity of the second harmonic light reaches at least a predetermined value.

Abstract: A laser-frequency stabilizer includes: a light detector that converts a laser beam passing through an iodine cell to an optical output signal, an actuator that changes a resonator length in accordance with a received output voltage, and a control unit that controls the output voltage applied to the actuator. The control unit searches for a target saturated absorption line based on the optical output signal and, when the output voltage when the target saturated absorption line is found is within a normal voltage range that is predetermined corresponding to the target saturated absorption line, locks a oscillation frequency of the laser beam to the target saturated absorption line.

Abstract: A laser-frequency stabilizer includes: a light detector that converts a laser beam passing through an iodine cell to an optical output signal, an actuator that changes a resonator length in accordance with a received output voltage, and a control unit that controls the output voltage applied to the actuator. The control unit searches for a target saturated absorption line based on the optical output signal and, when the output voltage when the target saturated absorption line is found is within a normal voltage range that is predetermined corresponding to the target saturated absorption line, locks a oscillation frequency of the laser beam to the target saturated absorption line.

Abstract: An optical resonator includes a casing and various optical elements (laser crystal, SHG, etalon, movable mirror) provided within the casing. The optical resonator causes light from the excited laser crystal to resonate and, using the etalon, emits single longitudinal mode laser light. The casing is formed with a low thermal expansion metal exhibiting a thermal expansion coefficient within a range of 0.1 to 3.0×10?6K?1 and thermal conductivity within a range of 10 to 15 W·m?1·K?1. A first temperature control system controlling the temperature of the laser crystal and SHG to be a constant temperature is provided at a placement portion of the laser crystal and SHG. An angle adjuster adjusting an incident angle of the etalon and a second temperature control system controlling the temperature of the etalon to be a constant temperature are provided at a placement portion of the etalon.

Abstract: An optical encoder includes a light source fiber holder holding a light source fiber and a collecting lens therein, and a nut. The light source fiber holder includes an end fitting together with a light source base. An outer circumferential surface of the end includes an inclined surface inclining such that a cross-sectional area increases as the surface approaches the light source fiber; and a projection capable of advancing into a groove of the light source base. The optical encoder includes a light source connector and the light source fiber holder.

Abstract: An optical encoder includes a light source fiber holder holding a light source fiber and a collecting lens therein, and a nut. The light source fiber holder includes an end fitting together with a light source base. An outer circumferential surface of the end includes an inclined surface inclining such that a cross-sectional area increases as the surface approaches the light source fiber; and a projection capable of advancing into a groove of the light source base. The optical encoder includes a light source connector and the light source fiber holder.

Abstract: To provide a surface profile measurement apparatus capable of efficient measurement of the surface profile of an object. A diamond indenter (16) is movably mounted. The tip end of the diamond indenter (16) is irradiated by light, and the light reflected by the tip end (17) is condensed through a lens (46). The condensed light is observed by a photo sensor (42) for measurement of the curvature radius of the tip end (17). Meanwhile, the light reflected by the tip end (17) and the light reflected by a reference body (66) together cause an interference fringe. The interference fringe is observed by a CCD camera (44) to measure the surface profile of tip end (17).

Abstract: A first friction clutch (54) is constructed as a negative type friction clutch and a second friction clutch (55) is constructed as a positive type friction clutch. Spring constant of a second spring (75) is made smaller than that of a first spring (65). Therefore, in the middle stage of switching the first and second friction clutches (54, 55), both of these first and second friction clutches (54, 55) enter in a connection state. Consequently, a driven member (56) is driven through either or both of the first and second clutches by a driving shaft, and the free rotation state does not occur.

Abstract: To provide a surface profile measurement apparatus capable of efficient measurement of the surface profile of an object. A diamond indenter (16) is movably mounted. The tip end of the diamond indenter (16) is irradiated by light, and the light reflected by the tip end (17) is condensed through a lens (46). The condensed light is observed by a photo sensor (42) for measurement of the curvature radius of the tip end (17). Meanwhile, the light reflected by the tip end (17) and the light reflected by a reference body (66) together cause an interference fringe. The interference fringe is observed by a CCD camera (44) to measure the surface profile of tip end (17).

Abstract: In a brake (53) for a hydraulic motor (10), a braking piston (66) is added that can move toward and away from fixed friction discs (54) and rotating friction discs (55). A braking passage (73) leads a high-pressure fluid into the braking piston (66) to press the braking piston (66) to the friction discs (54, 55).

Abstract: An interferometer and method for performing preliminary and main measurements quickly and with high precision are provided. Laser light and white light are successively introduced to the same interferometer booth. Laser light is introduced from a laser light source, and the interference fringe with a reference mirror as a reference is detected using a CCD and a personal computer. By setting the interference fringe to a preset value, the position of a work is adjusted. White light from a halogen lamp is then introduced, a corner cube moving mount is moved, interference fringe with a reference mirror as a reference is detected, and preliminary measurement of the work is performed. Next, laser light is introduced, interference fringe with a reference mirror as a reference is detected, and the main measurement of the work is performed.