Method and apparatus for recording signals on a record carrier, measurement method and measurement device for use in the recording method and the recording apparatus, and record carrier

Claim 3

A method as claimed in Claim 1, characterized in that the optically detectable marks are magnetic domains obtained by locally heating a recording layer of the record carrier with the aid of a radiation beam, said layer being suitable for magneto-optical recording, the heated portion of the recording layer being exposed to a magnetic field which is directed substantially perpendicularly to the recording layer.

Claim 4

A method as claimed in Claim 2, characterized in that the magnetic field is modulated in conformity with a signal to be recorded.

Claim 5

A method as claimed in Claim 2 or 3, characterized in that the dimensions of the optically detectable marks are adjusted to obtain dimensions corresponding to the track pitch by adjusting the intensity of the radiation beam.

Claim 6

A method as claimed in Claim 4, characterized in that the method comprises a measurement method in which in a specific track portion a first test signal is recorded with a maximum write intensity of the radiation beam and in track portions situated at opposite sides of said specific track portion a second test signal, which can be distinguished from the first test signal, is recorded with different write intensities between a minimum intensity and the maximum intensity, upon rich second test signal, after it has been recorded, is read from the specific track portion to check whether the second test signal being read contains signal components corresponding to the first test signal, and in which on the basis of the results of said check an optimum write intensity is selected which is situated in the boundary region between the intensity range for which signal components corresponding to the first test signal are present in the second test signal being read and the intensity range for which said signal components are substantially absent in the test signal being read, the write intensity being adjusted to the optimum write-intensity value after the measurement method has been carried out.

Claim 7

A method as claimed in Claim 5, characterized in that the first and the second test signal are periodic signals.

Claim 8

A measurement method for use in the method as claimed in Claim 4, 5 or 6.

Claim 9

A recording apparatus for recording signals in parallel tracks of a specific track pitch on a record carrier of a rewritable type, which recording apparatus comprises scanning means for scanning the tracks by means of a radiation beam to form an information pattern of optically detectable marks in the tracks, which patterns correspond to the signals, characterized in that the recording apparatus is adapted to form marks whose dimensions in a direction perpendicular to the track direction substantially correspond to the track pitch.

Claim 10

A recording apparatus for recording signals in parallel tracks of a specific track pitch on a record carrier of a rewritable type, which recording apparatus comprises scanning means for scanning the tracks by means of a radiation beam to form an information pattern of optically detectable marks in the tracks, which patterns correspond to the signals, characterized in that the recording apparatus is adapted to form marks whose dimensions in a direction perpendicular to the track direction substantially correspond to the track pitch.

Claim 11

A recording apparatus as claimed in Claim 8, characterized in that the apparatus comprises adjustment means for adjusting the write intensity to a value for which said dimensions of the marks correspond to the track pitch.

Claim 12

A recording apparatus as claimed in Claim 9, characterized in that the apparatus comprises a measurement device comprising read means for reading the recorded signals with the aid of a read beam, test-signal-generating means for generating a first test signal and a second test signal which can be distinguished from the first test signal, control means for causing the first test signal to be recorded in a specific track portion when a specific maximum value of the write intensity is reached, for subsequently causing the second test signals to be recorded in the specific track portion and in track portions situated at opposite sides of said specific track portion with a number of didderent write-intensity values situated between a minimum intensity and the maximum intensity, and for causing the second test signals recorded with different write-intensity values to be read from the specific track portion, detection means for detecting signal components corresponding to the first test signal in the second test signals being read, selection means for deriving from the detected signal components an optimum write intensity which is situated substantially at the boundary between the intensity range for which signal components corresponding to the first test signal appear in the second test signals being read and the intensity range for which said signal components are substantially absent in the second test signals being read, the recording apparatus further comprising means for adjusting the write intensity to said optimum value after the optimum write intensity has been determined.

Claim 13

A recording apparatus as claimed in Claim 10, characterized in that the first and the second test signal are periodic signals of different frequency.

Claim 14

A recording apparatus as claimed in any one of the Claims 8 to 11, characterized in that the recording apparatus is a magneto-optical apparatus comprising a coil for generating a magnetic field in the portion of the track being scanned by the write beam.

Claim 15

A measurement device for use in a recording apparatus as claimed in Claim 10, 11 or 12.

Claim 16

A record carrier formed with substantially parallel adjacent tracks of substantially constant track pitch, which tracks exhibit an information pattern of optically detectable marks, characterized in that the dimensions of the marks in a direction perpendicular to the track direction are substantially equal to the track pitch.

Claim 17

A record carrier formed with substantially parallel adjacent tracks of substantially constant track pitch, which tracks exhibit an information pattern of optically detectable marks, characterized in that the dimensions of the marks in a direction perpendicular to the track direction are substantially equal to the track pitch.

Claim 18

A record carrier as claimed in Claim 5, characterized in that the record carrier is of a magneto-optical type, the marks comprising magnetic domains having a direction of magnetization substantially perpendicular to a recording plane of the record carrier.