A magnetooptic recorder-player

Claim 2

A magnetooptic recorder-player adapted to record and read information from a magnetooptic storage member having a laser means for shining a laser beam onto the magnetooptic storage member for reading information therefrom, erasing information recorded thereon or recording information bearing signals thereon,and readback circuit means for reading information from the storage member by detecting and demodulating light reflected from the storage member and supplied by said laser means in a single light beam; the improvement including, in combination: means for activating said laser means to either erase or record information bearing signals onto the storage member; means for relatively moving the laser beam and the storage member at a rate that the erasure or recording occurs in a portion of laser beam as it impinges on the storage member which is displaced from a leading edge of the laser beam such that an initial portion of the laser beam is reflected; and reading means for intercepting the reflected light and demodulating the reflected light to obtain an indication of the information previously recorded on the storage member that is being scanned by the laser beam for erasure or rerecording.

Claim 3

The recorder-player as claimed in Claim 1, further including, in combination: read means connected to said activating means for activating the laser to emit a light beam having an intensity less than that required to heat an area of the storage member to a Curie temperature and connected to the reading means for activating the reading means to sense reflected light from the storage member for reading the recorded information without altering the recorded informiltion.

Claim 4

A magnetooptic recorder-player having a laser means for emitting a laser beam to a magnetooptic signal storage member for locally heating the member to a temperature above the Curie point, and a bias means for directing the residual magnetization to a first of two possible residual directions, comprising the machine-executed steps of: relatively moving the storage member and the laser beam such that the laser beam scans a predetermined trace on the storage member; activating the laser to supply a beam intensity for raising the local temperature of the scanned portion to be above the Curie temperature and keeping the laser intensity and the relative speed of the storage member and laser beam that the portion of the local area under a predetermined leading portion of the beam is below the Curie temperature such that the reflected laser beam is modulated to indicate the initial residual magnetization; magnetically biasing the storage member at the local area to direct the magnetization upon cooling below the Curie temperature to said first direction; and sensing the residual magnetization in the trace in said leading or front portion of the laser beam as the beam scans the storage member and indicating the initial residual magnetization.

Claim 5

A magnetooptic recorder-player having a laser means for emitting a laser beam to a magnetooptic signal storage member for locally heating the member to a temperature above the Curie point, and a bias means for directing the residual magnetization to a first of two possible residual directions, comprising the machine-executed steps of: relatively moving the storage member and the laser beam such that the laser beam scans a predetermined trace on the storage member; activating the laser to supply a beam intensity for raising the local temperature of the scanned portion to be above the Curie temperature and keeping the laser intensity and the relative speed of the storage member and laser beam that the portion of the local area under a predetermined leading portion of the beam is below the Curie temperature such that the reflected laser beam is modulated to indicate the initial residual magnetization; magnetically biasing the storage member at the local area to direct the magnetization upon cooling below the Curie temperature to said first direction; and sensing the residual magnetization in the trace in said leading or front portion of the laser beam as the beam scans the storage member and indicating the initial residual magnetization.

Claim 6

The magnetooptic recroder-player as claimed in Claim 3, further including the machine-executed steps of: designating said first direction as an erasure direction of residual magnetization and said second direction as an information bearing direction of residual magnetization such that the prior recorded information is read out before the trace is erased to the erasure direction.

Claim 7

The magnetooptic recorder-player as claimed in Claim 3, further including the machine-executed steps of: designating said first direction as a direction of residual magnetization for carrying information and designating said second direction of residual magnetization as an erasure direction such that the information recorded before rewriting the trace area is read before rewriting.

Claim 8

The magnetooptic recorder-player as claimed in Claim 5, further including the machine-executed steps of: selectively reversing the bias for recording information on the trace area interspersed with erasure portions while reading the prior recorded information during the recording and using only one laser beam.

Claim 9

The magnetooptic recorder-player as claimed in Claim 3, further including the steps of: in one operation of the recorder-player, making the first direction an erasure direction such that erasure follows reading by scanning the storage member by a single beam; and in another operation of the recorder-player reducing the laser beam such that the heating of the storage member keeps the temperature of the recording layer below the Curie temperature such that the recorded information is read but not changed.

Claim 10

The magnetooptic recorder-player as claimed in Claim 3, further including the steps of: in one operation of the recorder-player, making the first direction an erasure direction; selectively alternating the magnetic polarity of a magnetic bias field which floods the area of the storage member illuminated by the laser beam such that readout occurs before the alternation of the residual magnetization; and alternating the bias field for recording information onto the storage member by a single beam which also reads the information from such storage member.

Claim 11

A magnetooptic recorder-player, including the machine-executed steps of: magnetically biasing a storage member in the recorder to a first direction of residual magnetization; shining a light beam onto the storage member in an area encompassed by the bias and having an intensity to gradually heat the area of the storage member receiving the light beam to above the Curie temperature; relatively moving the storage member and the light beam so that the light beam scans a trace on the storage member; and sensing any reflected light off the storage member from the light beam and analyzing the reflected light to indicate the direction of residual magnetization prior to shining of said light beam onto the storage member which is in said trace.

Claim 12

A magnetooptic recorder-player, including the machine-executed steps of: magnetically biasing a storage member in the recorder to a first direction of residual magnetization; shining a light beam onto the storage member in an area encompassed by the bias and having an intensity to gradually heat the area of the storage member receiving the light beam to above the Curie temperature; relatively moving the storage member and the light beam so that the light beam scans a trace on the storage member; and sensing any reflected light off the storage member from the light beam and analyzing the reflected light to indicate the direction of residual magnetization prior to shining of said light beam onto the storage member which is in said trace.

Claim 13

A magnetooptic recorder-player having laser and optical means for shining a single laser beam onto a storage member which is in an operative association with said means; the improvement including, in combination: first means in the recorder-player operatively coupled to the laser and optical means for actuating same to emit said single laser beam with an intensity for sensing any recorded information in the storage member without altering the residual magnetization of such storage member; second means in the recorder-player operatively coupled to the laser and optical means for actuating same to emit said single laser means with an intensity for changing the recorded information in the storage member; and reading means operatively coupled to the laser and optical means for receiving any light reflected by the storage member from the single laser beam at either of said light intensities whereby reading the storage member without changing the recorded information and reading the storage member with changing the recorded information may occur.

Claim 14

A magnetooptic recorder-player having laser and optical means for shining a single laser beam onto a storage member which is in an operative association with said means; the improvement including, in combination: first means in the recorder-player operatively coupled to the laser and optical means for actuating same to emit said single laser beam with an intensity for sensing any recorded information in the storage member without altering the residual magnetization of such storage member; second means in the recorder-player operatively coupled to the laser and optical means for actuating same to emit said single laser means with an intensity for changing the recorded information in the storage member; and reading means operatively coupled to the laser and optical means for receiving any light reflected by the storage member from the single laser beam at either of said light intensities whereby reading the storage member without changing the recorded information and reading the storage member with changing the recorded information may occur.