Abstract: A flow velocity determining apparatus (10) includes an irradiating unit (20) that emits irradiation light (L1) toward a liquid mixture (BL) which contains a non-spherical solid (BC) and a liquid (BP) and flows through a flow path (TB), a detecting unit (30) that detects reflected light (L2) emitted by the irradiating unit (20) and reflected by the liquid mixture (BL) flowing through the flow path (TB), the detecting unit (32) being disposed on at least one side of an optical axis (L2A) of the reflected light (L2) when seen in a plan view of an imaginary plane including an optical axis (L1A) of the irradiation light (L1) and the optical axis (L2A) of the reflected light (L2), and a determining unit (40) that determines a flow velocity of the liquid mixture (BL) by using a light amount of the reflected light (L2) detected by the detecting unit (32).

Abstract: A measuring apparatus is provided with: an irradiator configured to irradiate fluid with light; a first light receiver configured to receive a forward scatter component of scattered light scattered by the fluid; a second light receiver configured to receive a backscatter component of the scattered light; a third light receiver configured to receive a side scatter component of the scattered light; and an outputting device configured to output fluid information about the fluid, which is obtained on the basis of light receiving signals of the first light receiver, the second light receiver, and the third light receiver. According to this measuring apparatus, it is possible to output accurate fluid information because of the use of the forward scatter component, the backscatter component, and the side scatter component of the scattered light.

Abstract: A measuring apparatus is provided with: an irradiator configured to irradiate fluid with light; a first light receiver configured to receive a forward scatter component of scattered light scattered by the fluid; a second light receiver configured to receive a backscatter component of the scattered light; a third light receiver configured to receive a side scatter component of the scattered light; and an outputting device configured to output fluid information about the fluid, which is obtained on the basis of light receiving signals of the first light receiver, the second light receiver, and the third light receiver. According to this measuring apparatus, it is possible to output accurate fluid information because of the use of the forward scatter component, the backscatter component, and the side scatter component of the scattered light.

Abstract: An optical element includes a first microlens array unit and a second microlens array unit in each of which a plurality of microlenses are arranged. The first and second microlens array units are arranged opposite to each other with a distance which is longer than a focal length of the microlenses arranged in the first microlens array unit. The first microlens unit is arranged on a light-incident side with respect to the second microlens array unit. The interval between the microlenses arranged in the second microlens array unit is narrower than the interval between the microlenses arranged in the first microlens array unit. The optical element can appropriately suppress the occurrence of excessive pixel bright spot.

Abstract: An optical element includes a microlens array on which plural microlenses are arranged. The microlens array includes plural areas whose microlenses have different curvature radii per area. The plural areas are configured so that the farther the area exists from the center of the microlens array, the smaller the curvature radius of the microlenses arranged on the area is.

Abstract: An optical element includes a first microlens array unit and a second microlens array unit in each of which a plurality of microlenses are arranged. The first and second microlens array units are arranged opposite to each other with a distance which is longer than a focal length of the microlenses arranged in the first microlens array unit. The first microlens unit is arranged on a light-incident side with respect to the second microlens array unit. The interval between the microlenses arranged in the second microlens array unit is narrower than the interval between the microlenses arranged in the first microlens array unit. The optical element can appropriately suppress the occurrence of excessive pixel bright spot.

Abstract: An optical element includes first and second microlens array units on which microlenses are arranged. The microlenses are formed by lens contour having a polygonal shape in a plan view. The first and second microlens array units are arranged opposite to each other at a position where a distance between the first and second microlens array units is at least longer than a focal distance of the microlens, and are formed so that a direction of vertices of the lens contour of the microlens arranged on the first microlens array unit is different from a direction of vertices of the lens contour of the microlens arranged on the second microlens array unit. According to the above optical element, it is possible to appropriately suppress an influence of shift of the position between the first and second microlens array units, and it becomes possible to produce the optical element with ease.

Abstract: An optical element includes first and second microlens array units on which microlenses are arranged. The microlenses are formed by lens contour having a polygonal shape in a plan view. The first and second microlens array units are arranged opposite to each other at a position where a distance between the first and second microlens array units is at least longer than a focal distance of the microlens, and are formed so that a direction of vertices of the lens contour of the microlens arranged on the first microlens array unit is different from a direction of vertices of the lens contour of the microlens arranged on the second microlens array unit. According to the above optical element, it is possible to appropriately suppress an influence of shift of the position between the first and second microlens array units, and it becomes possible to produce the optical element with ease.

Abstract: The present invention makes possible a compact optical pickup device that eliminates effects due to the position where a sub beam is projected during tracking compensation, and provides for stable tracking compensation. A diffraction grating 12 in the optical pickup device PU gives an astigmatism to a sub beam (either of ±1-dimensional light), and shines that sub beam onto an optical disc DK. Also, a tracking error signal Ste is obtained by subtracting a push-pull signal PPsub that corresponds to a sub beam from a push-pull signal PPmain that corresponds to a main beam (0-dimensional light), and tracking compensation is performed based on that tracking error signal Ste.

Abstract: To reduce energy loss on an optical path and improve efficiency of using light volume of light source. A light beam in a P polarized state is emitted from a semiconductor laser 11, and simultaneously a first and second active ?/2 plates 1411 and 1412 are provided in a light path separation/composition unit 14. These first and second active ?/2 plates 1411 and 1412 are for example made of a liquid crystal panel, functions as a ?/2 plate in a turned-off state, and simply functions as a transmission film in a turned-on state. These turned-off and turned-on states are switched over in accordance with types of optical disc, and the optical beam with its polarized state controlled is separated with a third PBS 143. As a result, the light beam is irradiated onto the optical disc DK through a first objective lens 161 in the turned-off state of these first and second active ?/2 plates 1411 and 1412 and through a second objective lens 162 in the turned-on state thereof.

Abstract: The present invention provides an optical pickup device and an information recording/playback apparatus capable of correcting aberration of an optical beam in correspondence with a plurality of recording formats of optical disks while realizing miniaturization of the device and the apparatus and reduction in manufacturing cost. A collimator lens (161) is disposed on an optical axis in correspondence with a BD. By moving the collimator lens (161) in a direction parallel with the optical axis, spherical aberration is corrected in accordance with the BD. A collimator lens (162) is disposed on an optical axis in correspondence with a CD and a DVD. By moving the collimator lens (162) in a direction parallel with the optical axis, spherical aberration is corrected in accordance with the CD and DVD. The collimator lenses are integrally held by a lens holder (163). A step motor (164) moves the lens holder (163) so that the collimator lenses (161, 162) move in directions parallel with the optical axes.

Abstract: An optical pickup projects laser beams having the first to the third wavelengths, in response to the type of a recording medium which is an object to which recording or reproduction is to be performed, and reflecting light from the recording medium is received by a light-detecting element. In order to reduce the sizes of the optical pickup, light of the second and the third wavelengths is generated by a single dual-wavelength light source, and reflecting light of all the wavelengths is to be received by the single light-detecting element. A hologram element giving different optical effects to light of each wavelength is arranged between the light irradiating means and the light-detecting element. Thus, appropriate information recording and reproduction can be performed by using light of each wavelength.

Abstract: An optical pickup projects laser beams having the first to the third wavelengths, in response to the type of a recording medium which is an object to which recording or reproduction is to be performed, and reflecting light from the recording medium is received by a light-detecting element. In order to reduce the sizes of the optical pickup, light of the second and the third wavelengths is generated by a single dual-wavelength light source, and reflecting light of all the wavelengths is to be received by the single light-detecting element. A hologram element giving different optical effects to light of each wavelength is arranged between the light irradiating means and the light-detecting element. Thus, appropriate information recording and reproduction can be performed by using light of each wavelength.

Abstract: An optical pickup device including: a light source for emitting a light beam; a beam expander having a converging lens for converging a light beam, a light-shielding panel having a through-portion arranged at an optical conjugate position of an emission point of the light beam for allowing the converged light beam to pass through and a collimator lens for collimating the light beam passed through the through-portion; an objective lens for focusing the collimated light beam to the recording layer; and a light detector for detecting the light beam reflected by the recording medium and passed through the objective lens and the beam expander and generating the error signal and the reading data signal for controlling the focusing position.

Abstract: An optical pickup is provided for recording and reproduction of information onto and from an optical disk. In the optical disk, in a forward optical path, a single polarized optical beam is converted to plural polarized optical beams. Polarization modes of the plural polarized optical beams are then converted to a polarization mode suitable for one of the recording and the reproduction to produce polarization-converted optical beams and to radiate the polarization-converted optical beams to the disk. In the backward optical path, polarization modes of the polarization-converted optical beams reflected from the disk are returned to the same polarization mode as that of the plural polarized optical beams, so that plural polarized reflected optical beams are produced. Polarization modes of the plural polarized reflected optical beams are then returned to the same polarization mode as the single polarized optical mode.

Abstract: An optical pickup apparatus having an irradiation optical system for condensing a light beam on a track of a recording plane and a photodetection optical system for guiding return light to a photodetector to detect a focal error includes a holographic lens provided in the optical path of the return light for outputting 0-th and ±1st order diffracted lights based on the return light; an optical element provided in front of or behind the holographic lens for providing astigmatism; photodetectors for receiving the 0-th and ±1st order diffracted lights; and servo-signal generating operation circuits connected to the photodetectors for generating a first and second focus error signals having a first and second capture ranges based on the output signal of the photodetector.

Abstract: A tracking servo apparatus in which reflection light obtained when a laser beam is irradiated onto a recording surface of an optical disc is photoelectrically converted, thereby obtaining a photoelectric conversion signal, a tracking error signal showing a deviation amount of an irradiating position of said laser beam for a track in a disc radial direction on the recording surface is generated by the photoelectric conversion signal, a spherical aberration occurring in an optical system is detected, a level of the tracking error signal is corrected on the basis of the detection result, and the irradiating position of the laser beam is moved in the disc radial direction in accordance with the level-corrected tracking error signal.

Abstract: When recording/reading information data onto/from a recording medium by irradiating the recording medium with a first light beam, correction for decreasing the amount of spherical aberration is made just before the recording or reading. On the other hand, when recording/reading information data onto/from a recording medium by irradiating the recording medium with a second light beam, focus correction for correctly condensing the reflected light from the recording medium on the light receiving surface of a photodetector is made just before the recording or reading.

Abstract: A phase device for providing a phase difference between an inner radius portion and an outer radius portion of a light beam which is emitted from a light source is provided in an optical path between the light source of an optical pickup apparatus and an objective lens. The light beam to which the phase difference has been provided is converged by the objective lens and irradiated to an optical disc. An interference of an inner radius portion and an outer radius portion of the returning light beam caused when the light beam is diffracted by the optical disc with ±1 primary diffracted light caused by the diffraction is suppressed. Therefore, an intensity fluctuation of the returning light beam caused by the interference is suppressed. A spherical aberration error showing a thickness error of the optical disc and a focusing error having a high linearity can be detected with high precision on the basis of the returning light.

Abstract: A variable optical unit is provided with at least two phase-shift regions for providing light with phase differences. Phase-shift amount of the phase-shift region is adjusted by the applied voltage in accordance with birefringence of an information medium. A light beam emitted from a light source is incident on the variable optical unit through a collimator lens and a beam splitter. The light beam is polarized in accordance with the aforementioned phase-shift amount of the variable optical unit and converged by an objective lens to radiate the information medium. The reflected light polarized due to the effect of the birefringence of the information medium is polarized again according to the phase-shift amount of the variable optical unit. The reflected light is thereby polarized in the direction in which the beam splitter can reflect the reflected light and then the reflected light reflected by the beam splitter is detected by the condenser lens and an optical detector.