Victor Company of Japan, Limited

Adamant Kogyo Co., Ltd.

Kunio Goto

Yoshiyo Wada

Hisao Kinjo

Hideaki Takehara

Hitoshi Watanabe

Osamu Tajima

Atsumi Hirata

Keiji Ozawa

Kazuo Tatsuguchi

Keiji Segawa

Hideaki Miyatake

Kyusaku Suga

The lateral position of a magnetic head is controlled in response to tracking information derived from an adjacent guide track formed by a series of minute pits on a grooveless recording medium having ferromagnetic and dielectric properties. Microwave energy is applied to an electrode mounted for movement with the magnetic head to sense the variations in capacitance resulting from the geometrical variations of the minute pits. The recording medium comprises an underlying layer of ferromagnetic material in which the minute pits are formed in spiral or concentric pattern and an overlying layer of a dielectric material which conforms to the pit contours of the underlying layer.

Magnetic recording on tracking controlled grooveless medium having

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 reproducing stylus traces a track of a recording medium, in which track an information signal is recorded as variations of geometrical shape, and reproduces as variations in capacitance the information signal thus recorded. The reproducing stylus comprises a reproducing stylus main structure having a tip part with a flat sliding contact face for slidingly contacting at least one track of the recording medium at a time, and an electrode secured to the reproducing stylus main structure at the tip part thereof and adapted to trace one track and reproduce the information signal as the variations in capacitance in accordance with the variations in geometrical shape. The electrode has over a specific distance over the tip part of the stylus main structure from the extreme tip thereof, a width in the width direction of the track which is less than said width of the track. The extreme tip of the electrode having a flat or linear tip end contacting the track.

Stylus for reproducing information signals recorded on a recording medium

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 capacitance detection type stylus is attached to the free end of a cantilever which is supported on a vertically movable resilient pivot. A permanent magnet is fixed to the movable pivot. A servo-control coil is provided adjacent the permanent magnet to move it in response to angular displacement of the cantilever from a predetermined position. The pivot is moved in the direction of fluctuation of a disc record to maintain the stylus in a proper orientation with respect to the record surface.

Pickup arm with servo-controlled stylus

A recording system records a television video signal of 60 fields per second converted from a signal of the picture image content of a cinematographic film for projection at 24 film frames per second, in a manner such that the video signal has parts in each of which the picture image content of one and the same film frame continues during at least 4 fields thereof, along a spiral track on a rotating recording medium rotating at a rotational speed of 900 revolutions per second at a recording rate of 4 fields per revolution of the recording medium. The rotating recording medium thus recorded has a part on which the picture image content of one and the same film frame is recorded over a part of a length of the track corresponding to at least one revolution of the recording mediu

System using a rotating medium for recording cinematographic picture

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.

Capacitance detection type stylus with diamond body and electrode having

A signal pickup cartridge is mounted in a signal pickup device having pivot bearings and an actuator driven by the pivot bearings in response to a control signal. The pickup cartridge comprising a cantilever provided at a distal free end thereof with a reproducing stylus for tracing along a track which is formed on a rotary recording medium lying in a horizontal plane and has an information signal recorded therealong and thereby reproducing the information signal. The cantilever is supported at a proximal base end thereof by the pivot bearings in a swingable manner and, moreover, in a manner making possible displacement thereof in the longitudinal direction thereof. The pickup cartridge further comprises pressure contact mechanism for holding the cantilever when the pickup cartridge is in the state thereof prior to the mounting thereof in the signal pickup device and for causing the proximal base end of the cantilever to be pressed into contact with the pivot bearing when the pickup cartridge is in the mounted state in the pickup device, and elastic members capable of absorbing vibration provided at one part of the pressure contact mechanism and holding the cantilever at a part thereof near the proximal base end.

Signal pickup cartridge for reproducing signals recorded on rotating

A reproducing stylus traces a track of a recording medium, in which track an information signal is recorded as variations of geometrical shape, and reproduces as variations in capacitance the information signal thus recorded. The reproducing stylus comprises a reproducing stylus main structure having a tip part with a flat sliding contact face for slidingly contacting a plurality of track of the recording medium at a time, and an electrode secured to the reproducing stylus main structre at the tip part thereof and adapted to trace one track and reproduce the information signal as the variations in capacitance in accordance with the variations in geometrical shape. The electrode has over a specific distance over the tip part of the stylus main structure from the extreme tip thereof, a constant width in the width direction of the track which is less than the width of the track. The extreme tip of the electrode has a flat or linear tip end contacting the track.

Stylus for reproducing capacitive videodisc

A reproducing stylus traces a track of a recording medium, in which track an information signal is recorded as variations of geometrical shape, and reproduces as variations in capacitance the information signal thus recorded. The reproducing stylus comprises a reproducing stylus main structure having a tip part with a flat sliding contact face for slidingly contacting at least one track of the recording medium at a time, and an electrode secured to the reproducing stylus main structure at the tip part thereof and adapted to trace one track and reproduce the information signal as the variations in capacitance in accordance with the variations in geometrical shape. The electrode has over a specific distance over the tip part of the stylus main structure from the extreme tip thereof, a width in the width direction of the track which is less than the width of the track. The extreme tip of the electrode has a flat or linear tip end contacting the track.

A signal pickup device comprises a reproducing stylus for tracing a track on a rotary recording medium thereby to reproduce the information signal recorded thereon, a cantilever provided at a free distal end thereof with the reproducing stylus, means for supporting the cantilever so as to be rotatable about substantially proximal root end thereof and movable in an longitudinal direction thereof, coil means including at least two movable coils fixed to the support means, means for generating a control signal current in response to deviation of the tracing position of the reproducing stylus from a track to be traced, and supplying the control signal to the coils, and magnetic field forming means secured at a predetermined position of a main body of the device and adapted to apply to the coils a magnetic field in a direction parallel with the rotary recording medium. The coils undergo a motion due to a mutual interaction between the magnetic field and the current flowing therethrough, whereby the reproducing stylus is displaced by way of the cantilever at least in the width of the track and is thereby tracking controlled.

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Yokohama, Japan

Kunio Goto