Victor Company of Japan, Limited

Adamant Kogyo Co., Ltd.

Hideaki Takehara

Yoshiyo Wada

Kunio Goto

Shin Miyajima

Yasuo Shibata

Hitoshi Watanabe

Keiji Segawa

Kyusaku Suga

A magneto-optical storage medium and overwrite system comprises a first magnetic layer (reading/writing layer) (3), a second magnetic layer (auxiliary layer) (5) and a third magnetic layer (initializing layer) (7), each of which is a rare earth-transition metal alloy, and interface layers (4,6) for isolating magnetic exchange interaction between the magnetic layers, respectively. The second magnetic layer is initialized by the magnetization of the third magnetic layer (7) at room temperature. The first magnetic layer and/or the second magnetic layer is heated by a laser beam (P1) for demagnetization and remagnetization. The demagnetized portion of the second magnetic layer is remagnetized to the opposite direction by the demagnetizing field from the periphery. The demagnetized portion of the first magnetic layer is remagnetized to the same direction of the second magnetic layer.

Magneto-optical storage medium and magneto-optical overwrite system with

A tin-lead alloy for recording media, which consists essentially of from 30 to 70% by weight of tin and the rest being lead.

Tin alloys for recording media

An oxidation resistant soldering compound is deposited in a bore formed on an end of a ceramic shank. A diamond grain is placed in the bore of the shank and heated at an elevated temperature in a vacuum to solder the diamond with the ceramic shank. The soldered diamond and ceramic body are lapped into the shape of a stylus. The stylus is subsequently placed in an environment containing a small amount of oxygen and heated at a temperature lower than the solidus temperature of the soldering compound to convert the surface area of the diamond into a conductive layer of carbon which is lapped into an elongated form to serve as a stylus electrode.

Pickup stylus having fused diamond and ceramic bodies with conductive

A diamond body is heated in an environment of vacuum or inert gas containing a small amount of oxygen at a predetermined elevated temperature to allow the carbon atoms of the surface areas to form a layer of graphite on the diamond body. The diamond body is then lapped so that the graphite layer is shaped into the form of a stylus electrode.

Stylus having a graphite electrode

For detection of signals recorded in the form of minute pits along tracks as capacitance variations, a record stylus is disclosed as comprising a shank having a portion of cross-sectional area decreasing toward one end of the stylus. A diamond, partially embedded in the shank, has a decreasing cross-sectional area toward said end of the stylus as a continuation of the decreasing cross-section of the shank. The bottom and rear face of the diamond are inclined so that the adjacent angle therebetween is smaller than 90 degrees. An electrode attached to the rear face of the diamond extends from the bottom of the diamond toward the other end of the stylus. The electrode is thus inclined in a direction opposite to the direction of movement of the recording medium to provide less concentration of electric lines of force on the rear bottom edge thereof.

Record stylus for capacitance disks

A circuit arrangement comprises a first delay circuit which is responsive to the leading edge of a command signal to generate a first signal a delay time after the occurrence of the leading edge and a second delay circuit which is responsive to the trailing edge of the command signal to generate a second signal a delay time after the occurrence of the trailing edge. A stylus control solenoid responds to the leading edge of the command signal for lowering the stylus into slidable contact with the surface of a capacitance disc record and further responds to the second signal for lifting the stylus from the record. A high frequency source is arranged to respond to the first signal by generating high frequency energy for application to the electrode of a capacitance detection stylus and further responds to the trailing edge of the command signal.

Circuit arrangement for applying high frequency energy to a capacitance

A capacitance detection type record stylus comprises a conductive shank and a diamond partially embedded in the shank so that the diamond projects downwardly from one end of the shank. The shank is formed with a bottom face for making slidable contact with the disk record. The shank and diamond are formed with a pair of common rear faces inclined with respect to the axis of the stylus to define an electrode forming face therebetween which extends from the bottom face of the diamond partially into the shank. The electrode forming face is inclined at an acute angle with respect to the axis so that the lower end of the electrode forming face is located at a point forward with respect to the upper end thereof and subtends at the lower end thereof at such an angle that the diamond can be lapped without causing defects to occur on the lapped surfaces. The electrode forming face is entirely covered by a conductive layer so that the latter establishes electrical connection with the shank to allow signals detected by the electrode to pass through the shank to an external circuit.

Capacitance detection type record stylus having a conductive shank

A diamond body is irradiated with a pulsed laser beam in an environment containing a small amount of oxygen to convert the carbon atoms of the diamond into a conductive layer which serves as a stylus electrode. The conversion process may be preceded by a process in which the diamond body is placed in an environment containing a large amount of oxygen and irradiated with the laser beam to carbonate the irradiated area to form a groove so that the electrode can be formed on the bottom of the groove. This prevents the electrode from being damaged when the stylus pitches as it moves on the record surface.

Stylus having a conductive carbon layer

A stylus for use in detecting signals as electrostatic capacitance variations of the information recorded in the form of geometric variations on a surface of a recording disc comprises a diamond body and a stylus electrode formed on a surface of the diamond body by depositing a conductive substance having a strong affinity to carbon and heating the deposited diamond body to an elevated temperature to allow the carbon atoms of the diamond body to diffuse into the deposited conductive region to form a carbide compound. Hafnium, titanium or tantalum is found suitable as the conductive substance.

Stylus for detecting signals recorded as geometric variations and method

Method for making a stylus having a conductive carbon layer and a stylus

A diamond body is heated in an environment of vacuum of inert gas containing a small amount of oxygen at a predetermined elevated temperature to allow the carbon atoms of the surface areas to form a layer of graphite on the diamond body. The diamond body is then lapped so that the graphite layer is shaped into the form of a stylus electrode.

Method for making a stylus having a graphite electrode

A stylus for detecting signals as electrostatic capacitance variations of the information recorded in the form of geometric variations on a disc record comprises a diamond body and a stylus electrode attached to one surface of the body which makes contact with the disc record. The electrode extends downward to the plane of the contact face of the diamond body to detect the recorded information. The crystallographic orientations of the diamond body are such that the contact face is inclined at a predetermined angle to a crystallographic plane having the tendency to wear substantially at the same rate as the wearing rate of the electrode at its downward tip so that the electrode keeps contact with the record surface for a long period of use.

Growing community of inventors

Fujisawa, Japan

Hideaki Takehara