Abstract: An apparatus having a first system for forming a composite light beam of two light beams to be made to interfere with each other, a splitting member for amplitude-splitting the composite light beam into three or more split light beams in the same area, and a second system for obtaining interference light beams of different phases from the plurality of split light beams.

Abstract: This specification discloses an apparatus comprising a first system for forming a composite light beam of two light beams to be made to interfere with each other, a splitting member for amplitude-splitting the composite light beam into three or more splitted light beams in the same area, and a second system for obtaining interference light beams of different phases from the plurality of splitted light beams.

Abstract: An angiographic catheter has exhibits elasticity as a whole and has at a distal end portion thereof a deformed portion that is curved into a desired shape when no external force is applied thereto. The deformed portion has at a distal end thereof a distal end opening. A plurality of minute side apertures are formed in a portion that is located toward a proximal end of the catheter from the deformed portion. These side apertures are arranged such that a reaction force generated by injection of a contrast medium (liquid) fed through a lumen of the catheter from the distal end opening is counterbalanced to the greatest possible extent by the contrast medium (liquid) injected from the respective side apertures.

Abstract: An apparatus for detecting the displacement information of an object has a light source, a diffraction grating for diffracting a light beam from the light source so that the light beam diffracted by the diffraction grating is incident on the object, and a photodetector for detecting the light from the object caused upon the incidence of the light beam thereon by the diffraction grating. Information regarding the relative displacement to the object along a predetermined direction is detected on the basis of a light detection signal from the photodetector. The diffraction grating is formed so that the light beam applied to the object may be condensed on the object in a direction in which the relative displacement to the object cannot be detected by the signal from the photodetector.

Abstract: An apparatus for detecting position change information of an object includes a contact member for contacting the object, and a detecting unit for obtaining position change information of the object by detecting a change in force applied from the object to the contact member.

Abstract: An apparatus for measuring displacement information of an object. The apparatus has a light source emitting a light beam, an electro-optical crystal member, a voltage applying system for imparting a predetermined frequency difference between light beams passing through two different areas in the electro-optical crystal member, and a light receiving system for receiving scattered light from the object to which the two light beams emergent from the electro-optical crystal member have been projected. The electro-optical crystal member is disposed so that a light beam from the light source may partly enter the two different areas to form the two light beams to which the predetermined frequency difference is imparted. The displacement information of the object is obtained from the scattered light received by the light receiving system.

Abstract: This invention relates to an apparatus for optically measuring the relative displacement of an object with a diffraction grating, and the apparatus has a light projection system for spot-projecting a light beam onto the diffraction grating and light detection means for receiving an interference light beam obtained by multiplexing diffracted light beams of different orders from the spot projection position on the diffraction grating in a state in which the wavefronts of the diffracted light beams are matched with each other. The relative displacement of the object is measured upon light reception of the light detection means.

Abstract: An optical displacement measuring apparatus including an afocal optical system within a plane containing paths of at least two light beams. The afocal optical system includes a first lens optical unit and a second lens optical unit having a focal length which is greater than the focal length of the first lens optical unit. The distance between a diffraction grating and the first lens optical unit is smaller than the focal length of the first lens optical unit. The second lens optical unit is a combination of a lens with a negative refractive power and a lens with a positive refractive power. Accordingly, the optical displacement measuring apparatus performs accurate measurements with a large measurement depth, even for the cases where an afocal optical system is constructed within a plane containing the paths of the two light beams and the working distance is increased without increasing the size of an optical head.

Abstract: A velocimeter includes a light source for irradiating light onto an object to be measured, a light-receiving element for receiving scattered light from the object and outputting a light-receiving signal upon receiving the scattered light, a signal processing circuit for obtaining velocity information of the object to be measured by performing signal processing of the light-receiving signal output from the light-receiving element, a bandpass filter arranged in the signal processing circuit and having a function of passing frequency components near the frequency of the light-receiving signal to be obtained when the object to be measured is in a still state, and a switch arranged in the signal processing circuit to activate the bandpass filter substantially in the signal processing circuit when the moving velocity of the object to be measured is low.

Abstract: A recording apparatus employs a control unit to compensate for any variations in the feed speed of a recording medium. The recording apparatus includes a recording unit for recording an image on a recording medium in accordance with the image data; a speed detection unit for detecting the actual feed speed of the recording medium or of a feed unit for feeding the recording medium; and a control unit for controlling the record timing of the recording unit in accordance with a difference between a reference feed speed and the actual feed speed of the recording medium or feed unit detected by the speed detection unit.

Abstract: An apparatus for measuring displacement information of a target object includes an illumination system, a photodetector, and an adjusting member. The illumination system causes a beam from a light source to be incident on the target object. The photodetector receives and detects light from the target object upon incidence of the beam from the illumination system on the target object. The displacement information of the target object is measured upon detection of the light by the photodetector. The adjusting member changes a light-receiving state of the light on the photodetector.

Abstract: A Doppler velocimeter determines a state of noise generation in a detection signal including a Doppler signal component based on comparison by a preceding/succeeding-signal comparator for comparing the detection signals before and after passing through a band-pass filter for cutting noise adjusted to the frequency of the detection signal, and/or includes a filter circuit for determining passage/interruption of the detection signal after passing through the band-pass filter from a relationship between the count value of a first counter, in which the output of a first frequency multiplier for multiplying the frequency of the detection signal by N is made to be a clock signal and a leading edge in the detection signal is made to be a reset trigger, and a leading edge in the detection signal, and/or includes an error signal generator for generating an error detection signal by detecting a periodic error in the detection signal after passing through the band-pass filter from a relationship between the count value

Abstract: Disclosed is a frequency shifter for shifting a frequency of incident light beams. The frequency shifter has an electro-optic element for making incident the light beam whose frequency is to be shifted, an electrode unit disposed on the electro-optic element, an electric charge imparting circuit for imparting an electric charge to the electrode unit and a discharging circuit for discharging the electric charges accumulated in the electrode unit. Disclosed also is an apparatus, having the frequency shifter, for optically measuring relative displacement data to a measured object.

Abstract: An apparatus for detecting the displacement information of an object to be measured has a light source, an electro-optical crystal disposed at the incidence position of a light beam from the light source, the light beam being modulated in the electro-optical crystal, the light beam being internally reflected at least once in the electro-optical crystal and emerging therefrom, and a light receiving element for receiving the light from the object to be measured to which the light beam having emerged from the electro-optical crystal is applied, the displacement information of the object to be measured being detected by the light reception of the light receiving element.

Abstract: An optical device, and an apparatus for detecting displacement information of an object using the optical device, include an electrooptical device for shifting a frequency of an incident beam by applying a voltage thereto and an optical system for converging the beam at least in a plane including an application direction of the voltage and traveling direction of the beam, and for decreasing a degree of change of the diameter of the converged beam at least in the plane so as to reduce the diameter of the beam incident on the electrooptical device at least in the application direction.

Abstract: A frequency shifter is capable of controlling the adverse influences of electric noise caused by the voltage applied to electrooptical elements of a frequency shifter. The frequency shifter modulates the phase of the luminous flux entering the electrooptical elements by applying a voltage to the electrooptical elements; the shifter is provided with a shield for electrically shielding the circuit for generating the voltage to be applied to the electrooptical elements and the electrooptical elements from an external circuit.

Abstract: This invention has as its object to provide a frequency tracking method, a frequency control apparatus (tracking apparatus) using this method, and a Doppler velocity meter using the same, which easily and quickly allow the center frequency of a band pass filter to coincide with the frequency of an input signal even when an input signal suffers from a large level drift.

Abstract: There is disclosed an optical device having an electrooptic crystal on which a light beam is to be incident, and electrodes for applying a predetermined voltage to the electrooptic crystal.The electrooptic crystal is disposed in an optical system in which the angles of light rays in the light beam temporally or spatially change, and the electrodes are disposed, so that its voltage application direction is parallel to both the optic axis of the electrooptic crystal and the direction of polarization of the light beam incident on the electrooptic crystal, or is parallel to one of the optic axis and the direction of polarization and is perpendicular to the other.

Abstract: A frequency shifter for modulating the frequency of an incident light beam is disclosed. This frequency shifter includes an electro-optic crystal portion to be arranged at an incident position, an electrode arranged on the electro-optic crystal portion, a voltage application unit for applying a voltage to the electro-optic crystal portion via the electrode, and a unit which is arranged at least at a portion of the electro-optic crystal portion to uniformize the temperature of the electro-optic crystal portion.

Abstract: In an apparatus wherein a recording medium is conveyed by a conveying system with the front surface of the recording medium opposed to recording heads and information is recorded on the recording medium by liquid droplet jet, a first speed meter is provided on the back side of the recording medium and further, a second speed meter for detecting liquid droplet jet speed together with the first speed meter is provided at a predetermined location, whereby the recording position is adjusted. The first and second speed meters may preferably be optical Doppler velocimeters which will not cause any speed detection error with fluctuation of the wavelength of a light source.