Abstract: A light condensing lens includes a plurality of lenses disposed side by side in a splitting direction of a view angle to condense incident light over a range corresponding to respective split portions of the view angle. The view angle is split in a direction orthogonal to an optical axis of the incident light.

Abstract: A light directing system including first and second relay lenses through which light passes, the first and second relay lenses being positioned at conjugate positions, the first relay lens being positioned between the second relay lens and a light source, a focal length of the first relay lens being longer than a focal length of the second relay lens.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.

Abstract: An optical pickup for performing recording and/or playback of information by selectively irradiating the corresponding wavelength optical beam to first through third optical discs having a protection layer with different thickness, includes emission units for emitting first-wavelength through third-wavelength optical beams corresponding to the respective optical discs respectively, a condensing optical device for condensing each wavelength optical beam on an optical disc signal recording face, a divergence angle transformation device, which can be moved in the optical axis direction, for transforming the divergence angle of each wavelength optical beam according to the moved position in the optical axis direction so as to obtain a predetermined divergence angle, and a detector having a common light receiving unit for receiving each wavelength optical beam separated by an optical path separating unit and returned, with the condensing optical device condensing each wavelength optical beam on the corresponding o

Abstract: A light condensing lens includes a plurality of lenses disposed side by side in a splitting direction of a view angle to condense incident light over a range corresponding to respective split portions of the view angle. The view angle is split in a direction orthogonal to an optical axis of the incident light.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.

Abstract: An optical pickup for performing recording and/or playback of information by selectively irradiating the corresponding wavelength optical beam to first through third optical discs having a protection layer with different thickness, includes emission units for emitting first-wavelength through third-wavelength optical beams corresponding to the respective optical discs respectively, a condensing optical device for condensing each wavelength optical beam on an optical disc signal recording face, a divergence angle transformation device, which can be moved in the optical axis direction, for transforming the divergence angle of each wavelength optical beam according to the moved position in the optical axis direction so as to obtain a predetermined divergence angle, and a detector having a common light receiving unit for receiving each wavelength optical beam separated by an optical path separating unit and returned, with the condensing optical device condensing each wavelength optical beam on the corresponding o

Abstract: A plurality of light-emitting elements 9a, 9b, 10a each emitting laser beam of a wavelength of approximately 405 nm, approximately 660 nm or approximately 780 nm corresponded to each of a plurality of types of disc-formed medium 100, and an objective lens 18 condensing each laser beam emitted from the plurality of light-emitting elements so as to form an elliptic beam spot on a recording surface of the disc-formed recording medium are provided, wherein a long axis of a beam spot of the laser beam having a wavelength of approximately 660 nm is aligned in a direction 45° to 65° away from the tangential direction of the disc-formed recording medium, and a long axis of a beam spot of the laser beam having a wavelength of approximately 405 nm is aligned in a direction 25° to 45° away from the tangential direction of the disc-formed recording medium.

Abstract: An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.

Abstract: A plurality of light-emitting elements 9a, 9b, 10a each emitting laser beam of a wavelength of approximately 405 nm, approximately 660 nm or approximately 780 nm corresponded to each of a plurality of types of disc-formed medium 100, and an objective lens 18 condensing each laser beam emitted from the plurality of light-emitting elements so as to form an elliptic beam spot on a recording surface of the disc-formed recording medium are provided, wherein a long axis of a beam spot of the laser beam having a wavelength of approximately 660 nm is aligned in a direction 45° to 65° away from the tangential direction of the disc-formed recording medium, and a long axis of a beam spot of the laser beam having a wavelength of approximately 405 nm is aligned in a direction 25° to 45° away from the tangential direction of the disc-formed recording medium.

Abstract: The present invention provides an optical pickup and a disc drive apparatusx` that make it possible to record information signals to and reproduce information signals from disc-shaped recording mediums of three different types by means of a single objective lens.

Abstract: A cylindrical lens 39 for generating focussing error signals is formed as one with a portion of an optical component 33 of a transparent material lying on an optical path L2 that is an optical path of a return light beam from the optical member 33. This configuration assures a small size while reducing the production cost and improving operational reliability.

Abstract: An optical head includes a (1) light radiating unit in which the relative positions of first and second light sources are set so that a straight line interconnecting a spot position of the laser light illuminated on an optical disc and a spot position of the second laser light similarly illuminated on the optical disc will be 45±15° with respect to a recording track on the optical disc and (2) a light receiving element having plural light receiving sections arranged substantially parallel to a splitting line substantially parallel to the straight line which interconnects the spot position of the laser light illuminated on an optical disc and the spot position of the second laser light similarly illuminated on the optical disc and which is projected on the optical disc.

Abstract: An objective lens comprises a single objective lens adapted to a finite system having first and second aspherical surfaces and a hologram is formed on at least one of said aspherical surfaces. The light of the positive 1st order or that of the negative 1st order of the hologram is subjected to optimal correction of spherical aberration under actual operating conditions. When a semiconductor laser is used as light source, the change in the spherical aberration caused by the change in the refractive index arising as a result of the change in the environmental temperature of the medium between the first surface and the second surface is substantially offset by the change in the spherical aberration of the hologram attributable to the change in the oscillation wavelength of the semiconductor laser of the light source caused by the change in the environmental temperature so that, if the objective lens has a numerical aperture greater than 0.

Abstract: An optical head includes a light radiating unit in which the relative positions of first and second light sources is set so that a straight line interconnecting a spot position of the laser light illuminated on an optical disc and a spot position of the second laser light similarly illuminated on the optical disc will be substantially perpendicular to a recording track on the optical disc, and a light receiving element having plural light receiving portions which are obtained on splitting by a splitting line substantially parallel to the straight line interconnecting the spot position of the laser light illuminated on an optical disc and the spot position of the second laser light similarly illuminated on the optical disc and which is projected on the optical disc.

Abstract: An objective lens comprises a single objective lens adapted to a finite system having first and second aspherical surfaces and a hologram is formed on at least one of said aspherical surfaces. The light of the positive 1st order or that of the negative 1st order of the hologram is subjected to optimal correction of spherical aberration under actual operating conditions. When a semiconductor laser is used as light source, the change in the spherical aberration caused by the change in the refractive index arising as a result of the change in the environmental temperature of the medium between the first surface and the second surface is substantially offset by the change in the spherical aberration of the hologram attributable to the change in the oscillation wavelength of the semiconductor laser of the light source caused by the change in the environmental temperature so that, if the objective lens has a numerical aperture greater than 0.

Abstract: An optical pickup and an optical disk unit based on the optical pickup, which are capable of reducing their sizes, and of providing a low-cost construction, and further, of allowing accurate servo. The optical pickup comprises an optical separating section which is, in its optical source side surface, equipped with a first diffraction grating and an optical path branching section composed of a plurality of surfaces having normal vectors different from each other, and which is, in its optical disk side surface, equipped with a second diffraction grating composed of a continuous area. The first diffraction grating divides light from a light source into main and side beams, while the second diffraction grating allows the light from the light source to pass and diffracts the returning light from an optical disk toward the optical path branching section. The optical path branching section divides the returning light from the optical disk to lead the divisions to light-receiving sections of an optical detector.

Abstract: In an optical pick-up device, a first photodetector is disposed in such a position as to detect a light beam which is part of a light beam reflected from an optical disk and split in a direction different from a light source direction, and a second photodetector is disposed in the vicinity of the light source so that it can detect a light beam which is the other part of the light beam reflected from the optical disk and split in the light source direction, wherein a tracking control signal and a reproducing signal are detected by the first photodetector and a focusing control signal is detected by the second photodetector.

Abstract: An optical pickup apparatus for recording information signals on an optical recording medium. The apparatus includes a light source radiating a diverging light flux, an object lens on which a light flux radiated from said light source is incident, for converging the light flux on the optical recording medium, a light flux dividing device arranged at a position on a light path between the light source and the object lens at which the light flux remains a diverging light flux, which light flux dividing device divests reflected light flux from the optical recording medium out of the light path, a light detection unit for detecting the reflected light diverted from the light path by the light flux dividing device, and a polarized light dependent light flux separating device arranged at a position on a light path between the light flux dividing device and the light detection device at which the reflected light flux is a converging light flux.