In an optical storage system where an information bearing surface moves relative to a read/write head the latter includes a transparent body in which light beams sent to and from the surface are guided by multiple internal reflections. Beam shaping and focussing is effected by optical elements integrated in the surface of the body at the locations where the internal reflections occur. A distortion free imaging system is obtained with two series-arranged aspheric reflection surfaces which focus the beam on the information bearing surface. The separation of the input and the reflected beam paths is achieved with a polarizing beam splitter and an associated quarter-wave layer. For readout of a magneto-optic information bearing surface a nonperfect polarizing beam splitter is used in connection with a differential detection scheme to increase the signal to noise/ratio.
An optical head device for use in a disc player comprises a movable optical assembly in which an objective lens, first and second mirrors, and a light beam generating and detecting unit are supported in common by a supporting member, and a driving mechanism for moving the movable optical assembly in both a first direction along an optical axis of the objective lens and a second direction perpendicular to the first direction, wherein, in the movable optical assembly, a light beam generated in the light beam generating and detecting unit is reflected twice by the first and second mirrors to be changed in its traveling direction, and focused by the objective lens at a position on the optical axis of the objective lens, and a light beam coming from the outside of the movable optical assembly is received by the objective lens to pass therethrough to the second mirror, reflected twice by the second and first mirrors to be changed in its traveling direction, and guided to a photodetector contained in the light beam generating and detecting unit.
A carriage which is provided with a light beam focusing lens for focusing the light beam on an optical disc is made of light transmissible material, a light reflection part is formed at one end part in one body of the carriage, and a carriage holding mechanism is disposed on both sides in one body thereof so as to be movable in the radial direction of the optical disc, the light beam is applied to the carriage at the other end part thereof.
An optical integration element of the invention comprises a substrate possessing a light emitting element for emitting light, and a receiving sensor for receiving reflected light, an incident part composed of an optical transparent material for receiving the light from the light emitting element, a first reflecting part for reflecting the light entering from the incident part, a second reflecting part for reflecting by converting the light from the first reflecting part into nearly parallel light or convergent light, a condensing part for condensing the light from the second reflecting part, and an optical member forming an optical path transforming part for guiding the reflected light into the receiving sensor.
A light-guiding device having a light-incident surface and a light-outgoing surface for guiding light incident from the light-incident surface from the light-outgoing surface toward a light-receiving surface of a photodetector for generating an electric signal corresponding to a quantity of the received light. The device comprises a hologram layer having an interference pattern which acts as a diffraction grating to diffract and reflect the light, incident from the light-incident surface, in a predetermined direction. The hologram layer is interposed between first and second total reflection layers. The first total reflection layer has a first total reflection surface disposed in opposed relation to one of the longitudinal surfaces of the hologram layer so that the light diffracted and reflected by the hologram layer is incident on the first total reflection surface at a predetermined angle larger than the critical angle so as to be total-reflected thereon, and the second total reflection layer has a second total reflection surface disposed in opposed relation to the other longitudinal surface of the hologram layer so that the incident light passing through the hologram layer is incident on the second total reflection surface at a predetermined angle greater than the critical angle so as to be total-reflected thereon. This arrangement improves the light-receiving performance concurrently with reducing the thickness of the device.
A lens which has corrected the coma aberration substantially completely is provided as a catadioptric lens used with advantage in utilizing the evanescent light. The catadioptric lens is a concave non-spherical mirror having a concave refractive surface as a first surface S1 , a plane mirror as a second surface S2 and a concave non-spherical mirror arranged coaxially with the concave refractive surface of the first surface S1. The parallel incident light is converged through an aperture in the plane mirror of the second surface S2 on a total reflection plane of the fourth surface S4. The radius of curvature of the first surface S1 and the optical length d from the first surface S1 to the apex of the third surface S3 are set to satisfy the sine condition.
