Abstract: A distance measuring device measures a distance from a phase difference of beaten down processing signals even when fluctuations occur in a frequency of an oscillator. The distance measuring device includes a laser unit, a dividing device, a reference light receiving unit, and a measuring light receiving unit. The distance measuring device further includes an oscillator, a first mixer, a second mixer, a fourth filter, a fifth filter, a third mixer, a sixth filter, a second filter, a phase difference measuring unit, and a distance measuring unit. The phase difference measuring unit measures a phase difference of the two beat signals extracted by the sixth filter and the second filter. The distance measuring unit measures a distance based on the phase difference measured by the phase difference measuring unit.

Abstract: A distance measuring device measures a distance from a phase difference of beaten down processing signals even when fluctuations occur in a frequency of an oscillator. The distance measuring device includes a laser unit, a dividing device, a reference light receiving unit, and a measuring light receiving unit. The distance measuring device further includes an oscillator, a first mixer, a second mixer, a fourth filter, a fifth filter, a third mixer, a sixth filter, a second filter, a phase difference measuring unit, and a distance measuring unit. The phase difference measuring unit measures a phase difference of the two beat signals extracted by the sixth filter and the second filter. The distance measuring unit measures a distance based on the phase difference measured by the phase difference measuring unit.

Abstract: A surveying instrument and a surveying method for further minimizing a measurement error when the surveying instrument casts a light to a measuring object and receives the reflected light and measures a delay time or a distance. A reference pulse light r and a measurement pulse light o1 are received as a received light signal by a light receiving section 9, and a damping signal S3U is formed from the received light signals r, o1, and an amplification rate of a minute level signal in the proximity of a zero cross point Q0 of the damping signal S3U is greatly amplified, and timing signals r?, o1? are formed by using an amplified signal. Therefore, the measurement error can be minimized.

Abstract: A surveying instrument and a surveying method for further minimizing a measurement error when the surveying instrument casts a light to a measuring object and receives the reflected light and measures a delay time or a distance. A reference pulse light r and a measurement pulse light o1 are received as a received light signal by a light receiving section 9, and a damping signal S3U is formed from the received light signals r, o1, and an amplification rate of a minute level signal in the proximity of a zero cross point Q0 of the damping signal S3U is greatly amplified, and timing signals r?, o1? are formed by using an amplified signal. Therefore, the measurement error can be minimized.

Abstract: A pulse light receiving time measurement apparatus according to the present invention includes a light receiving element receiving reflected pulse light from an object to be measured; a pulse light receiving time measurement circuit measuring a time when pulse light is irradiated to the object and a time when the reflected pulse light from the object is received at the light receiving element; a resonance circuit converting an optical pulse signal of the reflected pulse light from the light receiving element into a damping signal; a multi-stage amplifier group amplifying the damping signal from the resonance circuit; a damping signal processing circuit composed of amplitude comparators and zero-cross comparators, and processing the damping signal from each stage of the multi-stage amplifier group, in which operations of the respective zero-cross comparators are determined according to comparison results of the respective amplitude comparators for the amplifier group.

Abstract: A deformable mirror control device is provided with improved response characteristic by devising the mode of control even if the deformable mirror has a large time constant in comparison with the response speed required in applications such as the retinal camera. The deformable mirror device comprises a deformable mirror 10 having a reflective surface deformed with an applied voltage, and a voltage control circuit 20 for controlling the voltage applied to the deformable mirror 10. Here, the voltage control circuit 20 produces a steady-state voltage at which the reflective surface of the deformable mirror 10 takes an intended shape in a steady state, and produces a transient voltage that causes the reflective surface of the deformable mirror 10 to deform toward the intended shape, and also produces a transient voltage that causes the shape of the reflective surface of the deformable mirror 10 to shift quickly toward the intended shape.

Abstract: A pulse light receiving time measurement apparatus according to the present invention includes a light receiving element receiving reflected pulse light from an object to be measured; a pulse light receiving time measurement circuit measuring a time when pulse light is irradiated to the object and a time when the reflected pulse light from the object is received at the light receiving element; a resonance circuit converting an optical pulse signal of the reflected pulse light from the light receiving element into a damping signal; a multi-stage amplifier group amplifying the damping signal from the resonance circuit; a damping signal processing circuit composed of amplitude comparators and zero-cross comparators, and processing the damping signal from each stage of the multi-stage amplifier group, in which operations of the respective zero-cross comparators are determined according to comparison results of the respective amplitude comparators for the amplifier group.

Abstract: A deformable mirror, in which the distance between an electrode substrate and a membrane can be accurately maintained and which can be produced at a low material cost, is provided. The deformable mirror comprises: an electrode substrate 11 having a plurality of electrodes (16a, 16b, 16c, 16d and 16e) formed on a surface of the electrode substrate; a silicon membrane 13 having a counter electrode opposed to the plurality of electrodes formed on the electrode substrate 11; a reflection section 15 provided on the side of the silicon membrane 13 opposite the counter electrode; and a support plate 19 integrally bonded to the electrode substrate 11 for restraining the displacements of the plurality of electrodes which adversely affect the deformation of the silicon membrane 13, in which a plurality of layers of wiring patterns (11a, 11b, 11c, 11d and 11e) for supplying drive voltages to the plurality of electrodes are formed in the electrode substrate 11.

Abstract: A deformable mirror, in which the distance between an electrode substrate and a membrane can be accurately maintained and which can be produced at a low material cost, is provided. The deformable mirror comprises: an electrode substrate 11 having a plurality of electrodes (16a, 16b, 16c, 16d and 16e) formed on a surface of the electrode substrate; a silicon membrane 13 having a counter electrode opposed to the plurality of electrodes formed on the electrode substrate 11; a reflection section 15 provided on the side of the silicon membrane 13 opposite the counter electrode; and a support plate 19 integrally bonded to the electrode substrate 11 for restraining the displacements of the plurality of electrodes which adversely affect the deformation of the silicon membrane 13, in which a plurality of layers of wiring patterns (11a, 11b, 11c, 11d and 11e) for supplying drive voltages to the plurality of electrodes are formed in the electrode substrate 11.

Abstract: A deformable mirror control device is provided with improved response characteristic by devising the mode of control even if the deformable mirror has a large time constant in comparison with the response speed required in applications such as the retinal camera. The deformable mirror device comprises a deformable mirror 10 having a reflective surface deformed with an applied voltage, and a voltage control circuit 20 for controlling the voltage applied to the deformable mirror 10. Here, the voltage control circuit 20 produces a steady-state voltage at which the reflective surface of the deformable mirror 10 takes an intended shape in a steady state, and produces a transient voltage that causes the reflective surface of the deformable mirror 10 to deform toward the intended shape, and also produces a transient voltage that causes the shape of the reflective surface of the deformable mirror 10 to shift quickly toward the intended shape.

Abstract: A noncontact tonometer comprises an air current blowing means for blowing an air current against an eye, a cornea deformation measuring means for optically measuring a change in the shape of the cornea caused by the air current blowing means, and an arithmetic means capable of calculating the intraocular tension of the eye on the basis of the change in the shape of the cornea. Since the intraocular tension of the eye can be calculated on the basis of the change in the shape of the cornea by the arithmetic means, the pressure of the air current blown against the eye need not be high, which lightens load on the subject.

Abstract: A position detecting apparatus comprises a light emitter which activates a laser source to emit a light beam so that mode hopping occurs, an interference optical system which directs the light beam from the laser source to a measuring light path on which an object to be measured is located and a reference light path on which a reflection mirror is placed and merges the reflected light beams coming back on the light paths so that the reflected light beams interfere with each other, a light sensor which receives the interference light beam provided by the interference optical system, and a position detector which determines the position of the object of measurement based on the interference signals produced by the light sensor before and after mode hopping caused by the light emitter.

Abstract: A wavelength stabilizing light source apparatus comprising a light source, a beam splitter, a scanning mirror, a reflector, a first and a second light receiver, a phase detector and a wavelength stabilizer. The first light receiver receives a first interference signal formed from the interference between coherent light coming from the scanning mirror and coherent light reflected by the first reflecting surface. The second light receiver receives a second interference signal formed from the interference between the coherent light coming from the scanning mirror and the coherent light reflected by the second reflecting surface. The phase detector detects the difference in phase between the first and the second interference signal. The wavelength stabilizer stabilizes the wavelength of the light source by keeping constant the phase difference detected by the phase detector.

Abstract: A wavelength stabilizing light source apparatus comprising a light source, a beam splitter, a scanning mirror, a reflector, a first and a second light receiver, a phase detector and a wavelength stabilizer. The first light receiver receives a first interference signal formed from the interference between the coherent light coming from the scanning mirror and coherent light reflected by the first reflecting surface. The second light receiver receives a second interference signal formed from the interference between the coherent light coming from the scanning mirror and the coherent light reflected by the second reflecting surface. The phase detector detects the difference in phase between the first and the second interference signal. The wavelength stabilizer stabilizes the wavelength of the light source by keeping constant the phase difference detected by the phase detector.

Abstract: An absolute length measuring apparatus comprising light sources, a beam splitter, an object of measurement, a scanning mirror, a light receiver, sampling parts and a distance measuring part. The light sources emit alternately a plurality of coherent light beams having different wavelengths. The beam splitter splits the coherent light beam from the light sources into two optical paths. The object of measurement is located on one of the two optical paths stemming from the beam splitter. The scanning mirror is located on the other optical path stemming from the beam splitter and made movable in the direction of optical axis. The light receiver receives both the reflected light beam from the object of measurement and the reflected light beam from the scanning mirror through the beam splitter. The sampling parts generate sampling signals of various wavelengths by sampling the output of the light receiver every time the light sources emit a coherent light beam while scanned by the scanning mirror.

Abstract: An intraocular length measuring instrument including a light source having a short coherent length, a beam splitter for forming a measuring optical path across the interior of an eye to be tested and a reference optical path within the instrument, and guiding a beam of light from the light source to both the measuring optical path and the reference optical path, a first light receiving portion for interfering light reflected by an intraocular object to be measured after passing along the measuring optical path with light coming through the reference optical path and receiving a resultant interference light, an intraocular object position measuring portion for finding an optical path difference from an optical path length of the reference optical path and a peak position of a signal coming from the first light receiving portion, a light irradiating optical system for irradiating a light beam to the cornea of the eye to be tested, a light receiving optical system for introducing a reflected light from the corne

Abstract: A scanning optical device having a light source for illuminating an examination object such as eyground of a humaneye, a scanning illumination system for scanning and illuminating the examination object with the light, and a light receiving system for guiding the light reflected from the examination object to a light-receiving section. The scanning optical device also has a synchronous signal generating optical system capable of directly guiding the light from the scanning illumination system to the light-receiving section without the intermediary of the examination object, and a synchronizing signal extraction device for separating a synchronizing signal exactly synchronous with the image signal from the signal derived from the light-receiving section.

Abstract: Cr-Ni system austenitic heat-resisting steel exhibiting higher heat resistance than that of well-known austenitic stainless steels by means of which an atomic ratio of C being 0.05 to 0.30% to Ti being 0.01 to 0.8% and/or Nb (Ta) being 0.01 to 1.6% is within the range of 1.3 to 7, preferably 3 to 6 and the grain size is within the range of ASTM No. 3 to 8.

Abstract: An austenitic heat resisting steel exhibiting excellent strength for a long period of time services at an elevated temperature, coexistant-adding 0.02 to 1.0% Nb and 0.02 to 1.9% Zr or 0.02 to 1.0% Nb, 0.02 to 1.0% Zr and 0.02 to 1.0% Ti in addition to usual composition of a stainless steel, simultaneously adjusting the atomic ratio of said(Nb+Zr) or (Nb+Zr+Ti) to C within the range of 0.05 to 1.0, preferably 0.2 to 0.5.