SI8910138B - Optically readable record carrier of the inscribable type, apparatus for manufacturing such a record carrier, and apparatuses for recording and/or reading information on/from such a record carrier - Google Patents

Claims (17)

A optically readable recording medium (1) comprising a recording layer (6) for recording a sample of optically perceptible recording information, the recording medium (1) being provided with a servo-track (4) which in the area intended for recording information, shows the periodic modulation of the line, which may differ from the sample of information, characterized in that the frequency of modulation of the line is modulated by a position information signal comprising position code signals (12) alternating with signals (11) positional synchronization. Optically readable record carrier according to claim 1, characterized in that the position code signals (12) are signals modulated by a biphasic sign, wherein the position synchronization signals (11) have a signal waveform different from the signal modulated by biphasic sign. Record carrier according to any one of the preceding claims, characterized in that the width of the servo-track (4) is between 0.4.10-6 m and 1.25.10-6 m, wherein the modulation of the track is a track oscillation with an amplitude of essentially equal to 30.10-9 m. Record carrier according to any one of the preceding claims, characterized in that the average period of line modulation is between 54.10'6 m and 64.10-6 m, the distance between the starting positions of the sections of the tracks being modulated according to the positional synchronization. signaling signal (11), which corresponds to 294 times the average modulation period of the trace. Record carrier according to any one of the preceding claims, characterized in that the position code signal indicates the time required at the nominal typing speed to travel the distance between the start of the line and the position where the line modulates the line corresponding to the position signal (12). code. The record carrier according to claim 5, characterized in that the position code signal (12) is modulated according to the position information code, comprising at least a part similar to the absolute time code and contained in the EFM modulated signal according to the CD standard. Apparatus (181) for producing a record carrier (1) according to any one of the preceding claims, comprising an optical sensing system (196) for radiating a sensitive layer (185) of carrier along a track corresponding to a servo track to be formed, and a deflection device (190) for deflecting the radiation beam in such a way that the position of the beam incident on the radiation-sensitive layer (185) is deflected in a direction perpendicular to the deflection direction according to the control signal applied to the deflection device. characterized in that the apparatus comprises a signal generator (103) for producing a periodic signal acting as a control signal and the frequency of which is modulated according to a position information signal comprising position code signals (12) interchangeable with signals (11). ) positional synchronization. Apparatus according to claim 7, characterized in that the signal generator (103) comprises a modulator (118) for converting the position information code into a position information signal and an FM modulator (119) for modulating the frequency of the control signal according to the position information signal. Apparatus according to claim 8, characterized in that the modulator (103) comprises a biphasic character modulator (118) and means for generating waveform synchronization signals different from the biphasic character modulated signal. Apparatus according to claims 8 or 9, characterized in that the apparatus comprises means for generating a position information code of the type indicating the time required at the nominal speed of the recording medium to travel the distance between the starting position of the servo track and the position where the position information code is recorded as line modulation. Apparatus according to claim 10, characterized in that the apparatus comprises means for generating a position information code similar to the absolute time code contained in the EFM modulated signal according to the CD standard. Apparatus according to claims 7, 8, 9, 10 or 11, characterized in that the apparatus comprises means for maintaining the ratio between the palpation rate for the radiation of the sensitive layer and the average frequency of the control signal, this ratio being between 54.10 " 6 m and 64.10'6 m, wherein the signal generator is adapted to produce positional synchronization signals with a frequency equal to 294 times the average frequency of the control signal. Apparatus according to any one of claims 7, 8, 9, 10, 11 or 12, characterized in that the signal generator is adapted to give a control signal with an amplitude having a value for which the shift of the incident position has a radiation-sensitive layer. , the displacement corresponding to the control signal, the amplitude being substantially 30.10'9 m. 3 Apparatus (50) for recording information on a recording medium (1) according to any one of claims 1 to 6, wherein the apparatus comprises writing means (53) for recording a sample of recording characters representing information in the servo-line (4), due to wherein the writing means (53) comprises a tactile means (55) for sensing a servo-line (4) with a beam of radiation, a beam of radiation reflected or transmitted through a record carrier and modulated by a line modulation, a detector for detecting a reflected or transmitted beam of radiation and a circuit (57) for obtaining a clock signal with a frequency determined by modulation of the line by radiation detected by the detector, characterized in that it comprises an FM demodulation circuit (80) for recovering the position information signal from the clock signal and the signal separating means position codes and synchronization signals. Apparatus according to claim 14, characterized in that the apparatus comprises a biphasic sign demodulator (85) for recovering the position codes from the position code signals. Apparatus (50) for reading a record carrier (1) according to any one of claims 1 to 6, wherein in this record carrier (1) an information signal is recorded in the servo-line as a sample from the record signs, the apparatus comprising a typing device (53) for typing a servo-track (4) at a substantially constant speed by means of a beam of radiation, the beam of radiation being reflected or transmitted through a record carrier (1) and modulated by track modulation and a pattern of recording signs, a detector for detecting reflected or of the transmitted radiation beam, the circuit for obtaining the information signal representing the recorded information from the radiation beam detected by the detector and the circuit (57) for obtaining the clock signal whose frequency is given by line modulation from the radiation beam detected by the detector wherein the reading apparatus comprises an FM demodulation circuit (80) for recovering the position information signal from the clock signal and the position signal separating means (12) synchronization codes and signals (11). Apparatus according to claim 16, characterized in that the apparatus comprises a biphasic character demodulator for recovering the position code from the position code signals. PHILIPS ELECTRONICS N.V.