Abstract: Different tracks on an optical information recording medium are irradiated with first and second light spots for auto-tracking. The light of the first light spot via the recording medium is detected to produce a first detection signal and light of the second light spot via the recording medium is also detected to produce a second detection signal. On the basis of a difference between the first and second detection signals, a signal used for performing tracking control of a third light spot for recording or reproducing information is generated. When recording or reproduction of information is effected on/from one of a first recording medium having a track pitch P.sub.1 and a second recording medium having a track pitch P.sub.2 and the first and second recording media satisfy a relation P.sub.1 -P.sub.

Abstract: An optical information recording and/or reproducing apparatus for radiating a plurality of beams to an optical information recording medium to record information in the optical information recording and/or reproduce information recorded therein. The apparatus includes (i) an irradiation optical system, (ii) a diffraction grating for splitting a beam from the irradiation optical system into a plurality of beams, the diffraction grating having a plurality of different diffraction regions formed without overlapping with each other, the plurality of beams split by the plurality of diffraction regions being guided onto the optical information recording medium, and (iii) a detection optical system for detecting a beam from the optical information recording medium.

Abstract: An optical information recording and/or reproducing apparatus includes a stationary portion and a movable portion. The stationary portion has an irradiation optical system for emitting a beam for recording information in an optical information recording medium and/or reproducing recorded information, and a detection optical system for detecting a beam from the recording medium. The movable portion is movable relative to the stationary portion and has an objective lens. The movable portion has a first optical path for irradiating the beam from the irradiation optical system onto the recording medium and a second optical path for guiding the beam from the recording medium to the detection optical system. The first optical path and the second optical path are formed as partly different paths. A beam separator for separating the beam from the irradiation optical system into a plurality of beams is set in the specific path only for the first optical system.

Abstract: A specimen measurement apparatus and method includes sequentially moving individual specimens, radiating first and second radiation beams on first and second positions spaced apart from each other in a moving direction of the specimens, time-serially detecting light components emerging from specimens passing the first and second positions using the same light detector, and an optical selector, arranged in an optical path between the radiation positions and a light detector, for, when a specimen passes the first position, selectively guiding a light component having a first optical characteristic emerging from the specimen to the light detector, and for, when the specimen passes the second position, selectively guiding a light component having a second optical characteristic emerging from the specimen to the light detector.

Abstract: An optical information recording/reproducing apparatus includes a first spot forming system for forming a first recording light spot and a second recording light spot for recording information on an information recording medium, a second spot forming system for forming a first reproducing light spot and a second reproducing light spot for reproducing information from the information recording medium, and a moving device for effecting a relative reciprocating motion between the first and second spot forming systems and the information recording medium. The spot forming systems form the recording light spots and the reproducing light spots in a particular arrangement.

Abstract: An optical information recording-reproducing apparatus comprising a light source, which produces a recording light beam. The apparatus further comprises, a light source producing a reproducing light beam differing in wavelength from the recording light beam, a detecting optical system for detecting a light beam passed through a recording medium, and a beam shaping prism for shaping the light beams of the two light sources into predetermined intensity distributions, the beam shaping prism being constructed of a division prism comprising at least three prisms cemented together, a polarization dividing surface for transmitting the light beams from the light sources therethrough and reflecting the reflected light from the recording medium being formed on at least one of the dividing surfaces of the division prism, and a wavelength dividing surface for directing the reproducing light beam of the reflected light from the recording medium being formed on at least one other dividing surface.

Abstract: At least two light sources are provided for an optical information recording/reproducing apparatus. The light sources emit a recording light beam and a reproducing light beam to form a recording light spot and a reproducing light spot on a recording medium. A wedge glass plate is interposed in the optical path of the beams. The wedge glass plate is rotated to adjust one or both positions of the recording and reproducing light spots formed on the recording medium.

Abstract: A particle measuring device having a light source for irradiating particles to be examined, light wavelength convertor provided in the optical path of the a light source and at least emitting a light converted into the short wavelength side relative to the wavelength of the incident light from the light source, and photometer for photometering the light from the particles to be examined.

Abstract: This specification discloses a particle measuring apparatus characterized by means for passing a particle to be examined to a portion to be examined. First applying means applies an irradiating light from a first direction to the portion to be examined, second applying means applies an irradiating light from a second direction differing from the first direction to the portion to be examined. First and second photometering means photomets the lights radiated from the portion to be examined by the application of lights to the particle to be examined, relative to the first and second applying means, respectively.

Abstract: A particle analyzing apparatus is provided with applying means for applying a light beam to a particle to be examined, correcting means for multiplying the intensities of a plurality of components of scattered lights emitted from said particle to be examined which differ in scattering angle by a correction coefficient and adding them together, and operation means for calculating the particle diameter of said particle to be examined from the output value of said correcting means.