Abstract: An avalanche photodiode includes a multiplication layer and a photoabsorption layer, and the multiplication layer is formed of a semiconductor superlattice structure composed of a number of well layers each of which is formed of a short period superlattice of at least two kinds of semiconductors and which can be equivalently regarded to be a mixed crystal of the at least two kinds of semiconductors. In the short period superlattice, the mini-bands are formed within the superlattice well layers having its effective forbidden band width, which is larger than the forbidden band width in a bulk condition of a semiconductor layer constituting a well in the short period superlattice. Thus, the dark current due to the inter-band tunnel transition within the same well layer is decreased. Therefore, a low noise characteristics and a low noise and high response speed characteristics obtained by a high ionization rate ration can be simultaneously realized.

Abstract: Methods and apparatuses are disclosed for improving accuracy of recording and reproducing information onto and from a magneto-optic recording information medium. In the first method, a width of a mark formed by a relatively low intensity light beam between two kinds of light beam intensities used for recording information is made larger than a sum of a track land width and the maximum track offset of the light beam, thereby the mark formed by the relatively low intensity light beam covers the track land portion in its full width. In the first apparatus, a reflected light beam from the magneto-optic recording information medium is split into a reflected beam for information reproducing and a reflected beam for tracking and focusing servos at the reproducing, thereby the apparatus can remove part being affected by the track groove portion from the reflected light beam for information reproducing.

Abstract: Magneto-optical disk recording and reproducing devices and actuators and distance detectors for use therewith are disclosed. The mageneto-optical disk device comprises, in addition to the usual elements, a bimorph type actuator or an electromagnetic actuator for driving the magnetic head of the magneto-optical disk device. The bimorph actuator has a metallic shim whose width varies with respect to the longitudinal distance inversely porportional to the normal function of the first or the second free natural vibration mode. Alternatively, the bimorph type actuator have a recess formed on a bimorph element to expose a piezoelectric crystal which outputs a voltage corresponding to the acceleration of the vibration of the actuator; the driver circuit of the actuator reduces the driving voltage when the frequency of the voltage generated at the recess comes into the neighborhood of a higher resonance frequency of the actuator.

Abstract: Methods and apparatuses are disclosed for improving accuracy of recording and reproducing information onto and from a magneto-optic recording information medium. In the first method, a width of a mark formed by a relatively low intensity light beam between two kinds of light beam intensities used for recording information is made larger than a sum of a track land width and the maximum track offset of the light beam, thereby the mark formed by the relatively low intensity light beam covers the track land portion in its full width. In the first apparatus, a reflected light beam from the magneto-optic recording information medium is split into a reflected beam for information reproducing and a reflected beam for tracking and focusing servos at the reproducing, thereby the apparatus can remove part being affected by the track groove portion from the reflected light beam for information reproducing.

Abstract: A laser power measuring jig is adapted for use in measuring a laser power of a laser beam which is emitted from an optical head of an optical disk unit which records and/or reproduces information on and/or from a medium. The laser power measuring jig supplies power information related to the laser power of the laser beam to a power meter which measures the laser power. The laser power measuring jig includes a main jig body which has a size and a shape which are approximately the same as those of the medium, and this main jig body is loaded into the optical disk unit. The laser power measuring jig also includes a mechanism for outputting the power information outside the optical disk unit and supplying the laser power information to the power meter when the main jig body is loaded into the optical disk unit.

Abstract: Magneto-optical disk recording and reproducing devices and actuators and distance detectors for use therewith are disclosed. The magneto-optical disk device includes a bimorph type actuator or an electromagnetic actuator for driving the magnetic head of the magneto-optical disk device. The bimorph actuator has a metallic shim having a width that varies with respect to the longitudinal distance in inverse proportion to the normal function of the first or the second free natural vibration mode. Alternatively, the bimorph type actuator has a recess formed on a bimorph element to expose a piezoelectric portion which outputs a voltage corresponding to the acceleration of the vibration of the actuator. The driver circuit of the actuator reduces the driving voltage when the frequency of the voltage generated at the recess comes into the neighborhood of a higher resonance frequency of the actuator.

Abstract: A circuit board comprising: a core material made from magnesium, a magnesium alloy, or a magnesium-based composite material, and an electric circuit formed on the core material. A process for producing the circuit board comprises the steps of (1) forming an electrodeposition-painted coating on such a core material, (2) forming a polyimide resin coating on the electrodeposition-painted coating, (3) forming a via hole extending through the resin coating to the underlying electrodeposition-painted coating, (4) etching and removing the electrodeposition-painted coating in the region exposed in the bottom of the via hole while masking the other region with the resin coating thereby extending the via hole to the core material, (5) forming a metal film on at least a free surface of the resin coating and an inner surface of the extended via hole, and (6) etching the metal film by using a photoresist mask to form a conductor layer having a predetermined pattern.

Abstract: In an optical disk apparatus for recording information in pits formed on an optical disk by projecting a light beam onto the optical disk and heating an area of the optical disk corresponding to the pulse pattern of the information, the pulse pattern of the information to be recorded is discriminated, and on the basis of the discriminated pulse pattern, the timing to start on and end the emission of the light beam from the light source to the optical disk is modified, or the number of emissions and the duration of each emission is controlled so that the pattern of the pits are corrected to the shapes that ensure accurate regeneration of the information.

Abstract: A magneto-optic recording medium has a cartridge provided with a magnetization direction indicating portion for indicating the direction of magnetization of a second magnetic layer. Alternatively, the direction of magnetization of the second magnetic layer is recorded in advance in the first magnetic layer. The direction of magnetization of the second magnetic layer indicated or recorded is detected and recognized. A magnetic field oriented in an opposite direction to the direction of magnetization detected is imparted to the magneto-optic recording medium. Alternatively, predetermined information is recorded in the first magnetic layer, the direction of magnetization of the second magnetic layer is detected on the basis of a signal reproducing that information, and the direction of a magnetic field to be applied to the magneto-optic recording medium is set on the basis of the direction of magnetization thus detected.

Abstract: A vibration damping device is comprised of first and second axially spaced end housings adapted to be mounted on spaced apart structures, and has a tapered intermediate member mounted on the second housing converging toward an open end of the first housing. A piston is mounted on an end of a rod which is connected to the first housing and extends through a bore formed in the intermediate member and forms a restricted flow orifice extending between the spaced apart housings. A pair of elastomeric sleeves extend between the intermediate portion and the piston and the first housing to form a pair of fluid chambers connected by the orifice. An elongated electrode preferably contacts an electrorheological fluid flowing between the chambers through the orifice.

Abstract: A magneto-optic recording apparatus which has a magnetic field generator that applies a magnetic field with a constant direction to a magneto-optic recording information medium for overwriting information to improve accuracy of recording and reproducing information onto and from magneto-optic recording information medium and further has an auxiliary magnetic field generator that compensates a variation of intensity of a magnetic field generated by the magnetic field generator and applied to the magneto-optic recording information medium is disclosed as the first invention. Also, a magneto-optic recording apparatus which performs synchronous wave detection of the reflected light signals from the magneto-optic recording information medium and controls A.C.

Abstract: A magneto-optical recording apparatus records an information signal on a disk by illuminating a magnetic layer on the disk with a pulsed laser beam having a frequency at least twice the maximum frequency of the information signal, and applying a magnetic field with a polarity switched according to the information signal to the spot illuminated by the laser beam. To ensure erasure of old information, the apparatus can modify the peak power level, bottom power level, duty cycle, or frequency of the pulsed laser beam according to the radial position of the beam on the disk.

Abstract: A disc loading device loads a disc in position on a turntable for reading information on either face of the disc. A clamp plate having one disc centering member clamps the disc to the turntable having a second disc centering member. The centering member corresponding to the disc face to be read is used to center the disc. The clamp and a carriage are driven in synchronism through a slider plate having multiple cam portions and which is adapted to move only horizontally under control of a motor, gear, track, horizontal slots on a fixed plate, and pins which are attached to the track and a fixed plate and pass thru the horizontal slots. As the motor rotates, its direction and amount of rotation is transferred to movement of the slider plate. Cam slots on the slider plate receive pins connected to the carriage and the clamp member, the latter pins passing through vertical slots in the fixed plate such that horizontal movement of the slider plate causes vertical movement of the carriage and clamp member.

Abstract: An aluminum pipe according to the present invention is used in forming a plurality of bulged portions on the peripheral wall thereof. At the same time by bulging has been so refined as to exhibit an elongation of at least 40% and a recrystallization texture of up to 60 .mu.m in grain size during bulging. The aluminum pipe to be bulged is produced by a process characterized by drawing an extruded aluminum pipe at a cold working ratio of at least 40%, and thereafter annealing the drawn pipe at a temperature of 350.degree. to 420.degree. C., whereby the pipe is refined to exhibit the specified elongation and recrystallization texture.

Abstract: An optical type information record carrier is disclosed which includes an arrangement wherein the depth of the guide grooves is selected to be about (2N+1).lambda./8n (N=1, 2, 3, . . . ) and the inclination angle of the wall surface of the carrier is steep enough to ensure that the information recording medium will not adhere to the wall surface of the guide grooves, or will only adhere very weakly if it does adhere. Thermal conduction at the wall surface of the guide grooves is prevented so that extension of the recording bits is restricted.

Abstract: A flexible pipe joint system has three swivel joints on the both sides and in the central portion thereof, and two arm pipes connecting the swivel joints. The swivel joints have a stepped cylinder body, an elbow and a cap nut. The stepped cylinder body has a larger diameter portion and a smaller diameter portion. The elbow has a pipe connection portion to which a nipple provided with a flange on its outer end and a nut member on its outer periphery. A short cylindrical adapter is provided at one end of the arm pipe connected to the pipe connection portion of the elbow and to one end of the arm pipe connected to the smaller diameter portion of the cylinder body. The adapter and the nut member, respectively, have an outer diameter smaller than the inner diameter of the gasket and an inner diameter of an end portion of the cap nut.

Abstract: A catching apparatus has a body to which an open ended inflatable cylindrical tube is affixed, for sealingly catching a fluid filled object. The fluid filled object is caught by the surface of the tube when air is supplied to the space between the tube and the body. An inflation limiting member is provided in a part of an area in which the tube inflates, in order to limit the inflation of the tube to a desired region.

Abstract: A gripping head of a handling apparatus grips objects, such as lipsticks or the like by means of the inflated surface of the tube thereof. A fluid inlet is formed on top of the hard body, and a fluid path is formed in the hard body. The outer cylinder open at the lower end thereof is so fixed on the hard body as to contain the latter, and the above-mentioned tube open at both ends thereof is fixed at both the ends to the lower outside end of the outer cylinder and the hard body or to the upper and lower outer ends of the hard body. The object is caught by the catching head when the tube is inflated inwardly as the fluid such as air is supplied into the space between the tube and outer cylinder or into the inside space of the tube through the fluid path from the fluid inlet.

Abstract: A method of cooling a device with a cooling unit, using a metal sherbet, which is metal being in a state of a two-phase composition consisting of a liquid phase and a solid phase, as a heat conducting body put between the cooling unit and the heat generating device for transferring heat generated in the device to the cooling unit. The metal sherbet is metal, such as an In-Ga binary system, in which solids of an In-Ga solid solution are dispersed in an In and Ga liquid at a temperature obtained under normal operations of the device and the cooling unit.

Abstract: A method of cooling a semiconductor device with a cooling unit, using a metal sherbet, which is metal being in a state of a mixed phase consisting of a liquid phase and a solid phase, as a heat conducting body put between the cooling unit and the semiconductor device for transferring heat generated in the semiconductor device to the cooling unit. The metal sherbet is metal, such as In-Ga binary system, in which solids of In-Ga solid solution are dispersed in an In and Ga liquid at a temperature obtained under normal operations of the semiconductor device and the cooling unit.