Abstract: A photodetector fixing mechanism for fixing a photodetector, which detects reflected beams from a recording medium, on a base plate with screws wherein caul portions integrally formed with the base plate sandwich a mounting member mounted with the positioned photodetector with the base plate to prevent the mounting member from being in contact with the screw heads so as not to cause skid of the mounting member by turns of the screws.

Abstract: The present invention relates to an optical recording and/or reproducing apparatus which optically carries out operations of recording and/or reproducing of information on a data carrier, by irradiating a beam from an optical head to the data carrier. In the apparatus according to the present invention, the angle between the optical axis of the beam from the optical head and the surface of said data carrier is detected, and a temperature adjusting device brings about a difference in temperature between both surfaces of the data carrier on the basis of the detected result in respect to the angle. Then, the difference in temperature generates a thermal strain, and this thermal strain functions to cancel the strain which the data carrier has previously had. As a result, the surface of the data carrier is kept on a level, so that this surface can be vertical to the optical axis of the beam from the optical head.

Abstract: A magneto-optic recording a reproducing apparatus including a magneto-optic information-carrying medium having three magnetic layers. A magnetic bias field is generatedd by a third layer which is premagnetized in the direction parallel to the thickness thereof. A second layer is magnetized by a magnetizing unit. The laser beam incident on the layers is controlled to three intensities for writing and reading information.

Abstract: A magneto-optic information-carrying medium comprises three magnetic layers. A magnetic bias field is generated by a third layer which is premagnetized in the direction parallel to the thickness thereof.

Abstract: A billet is successively cold worked into a product such as a countershaft, an outer race for a constant-velocity joint, or the like by forming a chemically converted lubricating coating on a surface of the billet, forging the billet into an intermediate product at a temperature below a transformation temperature of the billet, covering a surface of said intermediate product with lubricating oil in a die cavity in a die assembly, and forging the intermdiate product at a temperature below the transformation temperature and before the intermediate product gains a predetermined hardness due to age hardening resulting from the first forging step.

Abstract: The storage medium for an optical data storage system is a contiguous laminate formed by a plurality of layers of photochemical hole burning material, such layers individually exhibiting inhomogeneous absorption spectrum characteristics spanning different, successive wavelength ranges. This arrangement greatly expands the cumulative or overall absorption band of the storage medium available for laser hole burning to implement data bit writing, and thus increases the storage density at each memory site.

Abstract: An information-carrying medium having the form of a disc is rotated around a central axis. The temperature of the disc is controlled by a temperature-adjusting element facing the surface of the disc.

Abstract: Information is recorded by creating recording hole at a predetermined wavelength position on a memory element with a characteristic of wavelength selective optical data storage. Because the memory element is pit-like, it causes diffraction of a light beam transmitted through or reflected by it. The diffracted beams are detected for positioning a beam spot right on the selected memory element.

Abstract: A recording medium for wavelength selective optical data storage has at least one memory element on which information is recorded by creating recording holes on the absorption spectrum thereof. The spectrum has at least one prerecorded hole for identifying the wavelength positions of the recording holes.

Abstract: A light beam emitted from a source is focused on an object. The beam reflected by the object passes through an optical member and is detected by a photodetector. The optical member has a reflecting surface the reflectivity of which varies continuously with respect to the angle of incidence.

Abstract: The present invention relates to an optical head for optically recording or reproducing information. In the optical head of the present invention a holder is provided with an optical element fixedly attached thereto. The holder is axially movable in a guide bore of a housing member and a tapped hole is formed in the circumference of the housing member which hole does not reach the guide bore so as to create a deformable bottom hole portion. When a screw is screwed into the tapped hole it presses against and deforms the bottom hole portion so as to engage the holder. Accordingly, with the optical head according to the present invention, the rotational torque generated when the screw is rotated is absorbed in the bottom portion of the tapped hole, so that the holder is not moved when the screw is screwed into the tapped hole, whereby the optical element fixedly disposed on the holder can be easily positioned at an appointed position.

Abstract: An optical head for optical recording and reproducing system comprising a light source, a first optical means for introducing a light beam from the light source into a guide groove formed in a recording surface of an information carrier, and a second optical means for separating a reflected light beam reflected from the guide groove from the light beam from the light source. The optical head also comprises an optical element having formed thereon at its center a cylindrical surface and on both sides slanted surfaces for dividing the reflected light beam into three, and a light receiving element having at least three light receiving units for receiving the respective light beams divided into three by the optical element.