Abstract: A registration system for registering a target registration object with respect to a predetermined reference position by using a registration mark formed on the target registration object includes the intensity measurement step of receiving a mark image for a predetermined period of time by a storage type sensor while an area of the target registration object which includes the mark is illuminated, the storage type sensor having elements whose positional relationship is known with respect to the mark image, the process of obtaining a center position of the mark image on the storage type sensor in a positioning direction in accordance with outputs from the elements of the storage type sensor obtained in the intensity measurement step, the distance calculation step of calculating a distance between the reference position and the center position obtained by the process, and the moving step of moving the target registration object by a distance corresponding to the distance obtained in the distance calculation st

Abstract: An optical fiber sensor, which has a detector section connected in a single optical path made of an optical-fiber cable and having a light-modulating element and an optical element connected in series. The light-modulating element has its birefringence degree changed in accordance with the physical quantity to be sensed, thereby to modulate the polarization state of the physical quantity. The optical element converts the polarization state of the physical quantity into the intensity of light. The sensor further comprises two light sources, which apply two light beams having different wavelengths .lambda..sub.1 and .lambda..sub.2 to one end of the optical path. The intensities P.sub.1 and P.sub.2 of the beams of the wavelengths .lambda..sub.1 and .lambda..sub.2, both emitted from the other end of the optical path, are detected. The intensities .lambda..sub.1 and .lambda..sub.

Abstract: A temperature measuring device intended to use the photoelastic effect of a transparent element. The present invention employs as the temperature sensing element a thermal expansion photoelastic cell comprising a photoelastic element and a stress generating element which are closely contacted with each other for yielding stress of anisotropy in the photoelastic element, which changes in response to changing ambient temperature, as the stress generating element is quite remarkably different in thermal expansion coefficient from the photoelastic element. An element is further provided to detect phase difference between two orthogonal light components passed through the photoelastic element which are one polarized component in a stress direction and the other component polarized in a direction perpendicular to the above stress direction when linearly polarized light is passed through the photoelastic element of the thermal expansion photoelastic cell.

Abstract: An optical system for irradiation comprising a light source, a lens, an optical fiber, a rectangular waveguide, an objective lens and a prism and an optical system for receiving light comprising an objective lens, an aperture and an optical fiber are arranged with their optical axes intersecting one another at a point P in a measuring volume. In the optical system for irradiation, the light emitted from the optical fiber and having an intensity distribution expressed by a normal distribution curve is changed to a light having a uniform intensity distribution and a rectangular cross section, which is irradiated through the prism to the point p in the measuring volume. A light scattered at an angle of 90.degree. by a particle flowing through the measuring volume is guided through the optical system for receiving light to a photodetector which converts the scattered light to an electric signal (current) called a scattered light pulse.

Abstract: A particle size measuring apparatus irradiates a number of particles to be measured with a laser beam, measures a light intensity pattern scattered by the particles to be measured, and calculates a relative particle size distribution of the particles to be measured from the measured value obtained.

Abstract: A droplet size measuring apparatus of the forward scattering method, wherein particles to be measured in a scattering zone having a predetermined scattering path length are irradiated with parallel laser beams. The irradiated beams are scattered by the particles and the scattering beams are detected by the photodetectors arranged at predetermined scattering angles. The output of the photodetectors are input to an arithmetic operating unit, thus the intensity distribution I(.theta.) of the scattered beams is measured. The droplet size distribution n(D) is calculated from the intensity distribution I(.theta.) using the following equation:I(.theta.)=.intg.{I.sub.0 exp(-l.intg.c(D)n(D)dD..intg.i(D,.theta.+.theta..sub.

Abstract: A particle diameter measuring device for measuring the particle diameter distribution of a number of particles to be measured, wherein a laser beam guided through a radiating optical fiber is re-formed by collimator lenses into parallel beams having an adequate diameter and is then irradiated onto the particles to be measured; a plurality of optical fibers are arranged along a circle whose center is a point P located in the particles, the receiving end of any of the optical fibers being directed toward point P. The optical fibers receiving the scattered light are arranged close to one another in the range of small scattering angles, while they are roughly arranged in the range of large scattering angles. A transmitted light enters into that optical fiber which is so arranged as to coincide with the laser beam incident direction, the intensity of this transmitted light being detected by a photodetector.