JPH0262896B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording method for a master of a rotating recording medium, and in particular, a method for recording on a master of a rotating recording medium, in which a photosensitive agent is coated on a substrate, by applying two types of modulated beams to the master for a certain period of time. The present invention relates to a recording method that simultaneously performs irradiation recording and then development processing.

Prior Art The present applicant previously filed Japanese Patent Application No. 51-38809 (Japanese Unexamined Patent Publication No. 52
-123205) and its divisional applications (e.g. Japanese Patent Application No. 123205) and its divisional applications (e.g.
25259 (Japanese Patent Application Laid-open No. 53-56001 and others), one of the two modulated beams is used to spiral the main information signal onto a rotating recording medium as a change in geometrical shape. Continuous recording is performed on a concentric or concentric main track, and approximately midway between each track center line of this main track (hereinafter referred to as
We have proposed a method in which a reference signal for tracking control is recorded in the approximately intermediate portion between each track using the other modulated beam, and this is reproduced.
As a result, tracking operation can be performed stably, and especially when applied to a scanning stylus regeneration type rotating recording medium, a stylus guide groove can be eliminated, the life of the scanning stylus can be extended, and special regeneration can also be performed. It has the following features.

Problems to be Solved by the Invention However, when recording on the master of a rotating recording medium to be reproduced by the above reproduction method,
The recording of the tracking control reference signal must not result in any recording loss periods in the main information signal, and the tracking control reference signal and the main information signal must be recorded so that they can be reproduced at their respective optimal levels. There is a need to.

Therefore, the present invention provides a recording method for a master disc of a rotating recording medium that satisfies the above requirements by using two types of modulated beams to irradiate and record the photosensitive material of the master disc at the same time and while spaced apart from each other at a constant interval. The purpose is to provide

Means for Solving the Problems The present invention provides a system in which first and second reference signals having different frequencies in a frequency range lower than the recording frequency range of the main information signal are chronologically transmitted every rotation period of the master. The reference signals are alternately switched and arranged alternately, and a third reference signal is generated for a predetermined period of time corresponding to one rotation period of the master at a position related to the switching of the first and second reference signals. and a first modulated beam obtained by modulating a light beam with the main information signal or a multiplexed signal of the main information signal and the third reference signal, and the alternately arranged reference signal and a predetermined period of time. A composite signal with the third reference signal, which is generated only in the same direction, or a second modulated beam obtained by modulating the light beam with the alternately arranged reference signals, respectively, The recording material is irradiated and recorded at the same time at a distance of about 1/2 track pitch, and then the master is developed to form a row of pits by the first and second modulated beams on the substrate of the master.
It is constructed so that recording is performed as a sub-track, and one embodiment thereof will be described below with reference to the drawings.

Embodiment FIG. 1 is a block system diagram of an embodiment of the recording method for a master disk of a rotating recording medium according to the present invention, and FIG.
Figures A to D show signal waveform diagrams for explaining the operation of Figure 1, respectively. In FIG. 1, a portion of the laser beam emitted from a laser light source 1 is reflected by a half mirror 2 and supplied to a light beam modulator 14, while a portion is transmitted and further reflected by a reflecting mirror 3. It is supplied to a rear light beam modulator 6. On the other hand, input terminal 4
The incoming color video signal to be recorded (shown in units of vertical synchronizing pulses 25 in FIG. 2A, and shown in units of horizontal synchronizing pulses 26 in FIG. Here, a suitable carrier path is subjected to frequency modulation (FM) to produce an FM wave, which is applied as a modulation signal to the optical beam modulator 6, where the laser beam is modulated.
As a result, the first modulated beam modulated according to the FM signal is extracted from the device 6. This first modulated light beam is reflected by a reflector 16, passes through a polarizing prism 17, is further reflected by a reflector 18, and enters an objective lens 19, where it is converted into a modulated light beam of the main information signal. After the light is focused, it is focused on a photosensitive agent 20b coated on a disk-shaped substrate 20a such as glass, and the geometric shape changes (pit row) through subsequent development processing.
A spiral or concentric main track is recorded. The substrate 20a and the photosensitive agent 20b are the master 21
, which are rotated synchronously at a constant speed by a motor (not shown).

On the other hand, the oscillator 10,
Switching pulses are applied to 11 and 12, and for example, the oscillation operation is performed during the positive polarity period, and the oscillation operation is stopped during the negative polarity period.
When the oscillators 10, 11 and 12 are in oscillation operation,
Single frequency f _P1 (e.g. 700kHz), f _P2 (e.g. 500k
Hz) and f _P3 (for example, 300kHz), respectively. Here, the input switching pulses to the input terminals 7 and 8 are, for example, 2 to 1 rotation of the recording master 20.
When recording a frame video signal, the vertical synchronization pulse 25 is separated from the color video signal to be recorded as shown in FIGS. The pulse shown in B and the synchronization signal part are separated from the input video signal, and the horizontal synchronization pulse shown in C in the same figure is separated and output every 1H (H is a horizontal scanning period) period.
Pulses whose pulse widths are phase synchronized with the horizontal blanking period (hereinafter abbreviated as H.BLK) of the color video signal to be recorded are used alternately every two frame synchronizations. The above pulse width is selected so that the tracking control reference signals f _P1 and f _P2 do not affect the color burst signal shown at 27 in FIG. 2C. As a result, the oscillator 10 generates the first tracking control reference signal f _P1
is 2 due to the time phase relationship shown in Figure 2C and D, respectively.
The frame period (1/15 seconds) is output, and then the second tracking control reference signal is output from the oscillator 11.
f _P2 is output for two frame periods with the time phase relationship shown in C and D of the figure, respectively, and in the same way, f _P1 ,
f _P2 is output alternately every two frames.

Here, a third index pulse is set as an index pulse during reproduction corresponding to the switching position of the reference signals f _P1 and f _P2 .
A reference signal f _P3 is output from the oscillator 12. In this case, if the main information signal to be recorded is a video signal, kickpatch control is performed during the vertical blanking period (hereinafter referred to as V.BLK) in order to perform special playback such as still image playback or slow motion playback. Therefore, the reference signal f _P3 is V.
It is inserted and recorded in the BLK part. FIG. 3A shows the V.BLK part of the recorded video signal. In the first horizontal synchronizing pulse part after the vertical synchronizing pulse and the equalizing pulse, as shown by 28a on the white side, an appropriate pulse is applied to the signal for a period of 2 to 3 H. f Possibly recorded as _P3 . However, during still image playback or slow motion playback, when the scanning needle is caused to perform a jerky movement using the signal f _P3 , generally after the first jerking, the scanning needle jumps over the track and immediately moves to the designated track. The image cannot be stabilized, some hunting may occur, and furthermore, due to the response characteristics of the tracking moving mechanism of the scanning needle, there may be some noise at the top of the screen due to the effects of the kickback. Therefore, in order to completely insert the kickback into V.BLK, the switching operation during signal recording and playback should be performed just before the end of the video _signal . For Figure 3A
It may be inserted and recorded at the timing position shown by 28b.

However, the present invention is not limited to tracking and reproducing discs on which video signals are recorded, but also tracks and reproducing discs on which only audio signals are recorded with FM or PCM with a sufficiently wide dynamic range. , you can play long-time or multi-channel discs with the same playback device by simply adding an adapter and playing those video discs and audio discs.
It can also be used for the purpose of compatible disc playback, in which case the audio information does not contain periodic information such as horizontal or vertical sync pulses, so f _P3 can be used as shown in Figure 3A. Since it is not appropriate to record with the signal waveform shown as 28a or 28b in terms of compatibility, it is desirable that _fP3 be recorded as shown below.

f _P3 is oscillated for an appropriate period at a predetermined phase position for one rotation of the recording medium, and is superimposed at an appropriate level on a predetermined portion of the main information signal by the synthesis circuit shown at 24 in FIG. Record on the same track as the main track.

f _P3 together with f _P1 and f _P2 are supplied to the combining circuit 13 for a predetermined period of time as shown in FIG. 2D and FIG. Recorded by

Among the methods described above and in (2), method (2) is more preferable than method (2) in terms of performing stable tracking servo operation. That is, during reproduction, which will be described later, it is essential to differentially reproduce the reference signal f _P3 and, based on this, to switch the tracking control polarity of the reproduced reference signals f _P1 and f _P2 every rotation period of the disk. In order to perform this stably, stable reproduction of the reference signal f _P3 is essential.

On the other hand, during tracking control in which the pick-up reproduction scanner is electronically controlled to follow the main track, ideally it is preferable to have the pick-up reproduction scanner follow the center line of the main track, but in reality it meanders slightly along the main track. Tracking control is performed.

For this reason, even if the reproducing scanner follows the main track while meandering, the reference signal f _P3 is better if the reference signal f _P3 is recorded on the main track.
Level fluctuations are small, so tracking control can be performed stably.

However, it goes without saying that tracking control can be performed even when the reference signal f _P3 is recorded on the sub-track and reproduced.

As an example, to explain the method, the output signal of the combining circuit 13 is applied as a modulation signal to the optical beam modulator 14, where it is converted into an optical modulation wave, and then the brightness of the output signal is converted into a second modulated optical beam. (beam light intensity) is adjusted to be attenuated more appropriately than the light intensity of the first modulated light beam by an optical filter 15,
It is directed into a polarizing prism 17, where its plane of polarization is offset by 90° from that of the first modulated light beam.
The output time division multiplexed signal of the synthesis circuit 13 (master 2
The composite signal of the reference signals f _P1 , f _P2 and f _P3 which are alternately switched and arranged alternately in time series every rotation period of 1 is as shown in FIG. 3C or D. Here, in Fig. 3C, f _P3 is at the switching position between f _P1 and f _P2 .
The waveform is shown when inserted and recorded as an intermittent oscillation pulse of 2 to 3 H periods corresponding to the pulse width of a predetermined periodic pulse with a sampling period of H units similar to f _P1 and f _P2 . Further, D in the figure shows a waveform when f _P3 is continuously recorded for a predetermined width period of 2H to 3H.

FIG. 3B shows the H-period pulse that is phase-synchronized with the video signal to be recorded or the reference pulse that should finely control the rotation of the recording master 20 when recording only audio information, and the reference pulse that should be used to finely control the rotation of the recording master 20 when recording only audio information.
The period indicated by 9 corresponds to the vertical blanking period of the video signal. This H-period pulse corresponds to the reference signals f _P1 , f _P2 ,
f _P3 and the phase relationship shown in FIGS. 3B, C, or D, respectively.

Note that f _{P1 and} f _P2 may be sequentially and alternately inserted into the portion where f P3 is inserted. However, even if f _P1 and f _P2 are missing for about 3 to 4 hours because the reference signal f _P3 is recorded, it actually does not cause any trouble to the tracking servo operation.

The second modulated light beam that has passed through the polarizing prism 17 passes through the reflecting mirror 18 and the objective lens 19 at the same time as the first modulated light beam, and then onto the photosensitive material 20b on the recording master 21 which is being rotated synchronously. It is irradiated moving in the radial direction at a predetermined pitch, and the geometric shape changes (pit row) through subsequent development processing.
For example, a spiral sub-track is formed. At this time, the incident optical path of the second modulated light beam to the objective lens 19 is adjusted with respect to the first modulated light beam by the polarizing prism 17, and the second modulated light beam is recorded and formed by the first modulated light beam. Sub-tracks are recorded and formed at approximately 1/2 track pitch (here, track pitch refers to the distance in the track width direction between both scanning center lines of adjacent tracks) with respect to the main track. Furthermore, even in the case of a disk that is applied to the scanning needle type signal reading format, no scanning needle guide groove is formed.

FIG. 4 shows a frequency spectrum of an example of a signal to be recorded by the recording method of the present invention. ，
and NTSC system color video signal and audio signal are frequency-modulated on a single carrier wave, and the shift frequency band (7 to 10 MHz) of the carrier wave in the modulated wave to be recorded on the main track, and the lower side band (2.5 to 10 MHz). 7MHz) and upper sideband (10-15MHz), respectively. The frequencies of the reference signals f _P1 , f _P2 , and f _P3 are selected in a frequency band lower than this lower sideband.

In FIG. 1, if it is inconvenient to divide the laser light source 1 into two beams due to the beam power, etc., another laser light source indicated by the broken line 22 is newly prepared, and the light beam intensity, modulation degree, etc. It may be configured such that the output light beam is appropriately adjusted with respect to the first modulated light beam, and the output light beam is reflected by the reflecting mirror 23 and supplied to the light beam modulation device 14. In this case, the emitted light beam of the laser light source 1 is supplied only to the light beam modulator 6.

Further, when recording a color video signal as a main information signal, each of the reference signals may be obtained by frequency-downgrading the color subcarrier.

Examples of track patterns on a cutting master or a pressed rotary recording medium recorded by the method of the present invention shown in FIG. 1 are shown in FIGS. 5A to 5D.
It will look like this. f _P1 , f _P2 , and f _P3 are recorded aligned in the direction of the center of the disk 30, which is an example of a rotating recording medium. Figure 5B is the same figure A
2 is a view showing the track pattern of the first embodiment, which is an enlarged _view of _a part of the circular area of the disk ₃₀ shown in FIG.
In the first, second, third, etc. main tracks recorded for one rotation of the disk 30, tracking control reference signals f _P1 and f _P2 are provided approximately in the middle between each main track. The pits are recorded alternately in one rotation period by intermittent pits at a depth shallower than the pit depth of the main track, and the third reference signal
f _P3 is the switching recording position 32 of f _P1 and f _P2 as shown by the broken line.
is recorded as a timing pulse (index pulse). When the main information signal consists of at least a video signal, f _P1 and f _P2 are 3 as shown in Figure 5B.
3, and f _P3 is V.
As described above, the information is recorded in the BLK portion.

FIG. 5C is a further enlarged view of the main part of FIG.
m), pit width (track width; e.g. 2.6 μm) 3
Approximately in the middle between each of the main tracks of No. 5,
A sub-track with a pit width (for example, 1.2 μm) indicated by 36 overlaps the main track at portions 37, 3.
7' shows the track pattern of the first embodiment recorded with 7'. When reproducing a disc with this track pattern, a single scanner reproduces the main information signal from the main track and at the same time f _P1 ,
f _P2 can be constantly compared as an analog quantity,
Therefore, it is possible to construct a stable servo loop in which the output level maintains a balanced state, and when recording the main track and the sub-track by the reference signal in an overlapping manner, the recording can be formed very closely.
It also has the advantage of increasing recording density.

In FIG. 5D, the track pitch 34 is 2.8 μm, which is the same as in FIG.
The main tracks are adjusted by 2.8 μm to match the track pitch 34 and eliminate blank areas between each main track.
FIG. 2 is a partially enlarged plan view of a track pattern of a second embodiment in which recording is performed with a track width of show. When this track pattern is recorded, it is more advantageous in terms of increasing the signal reading sensitivity and the recording density of the information track.

Next, to explain the reproducing system of a rotating recording medium, FIG. 6 shows a block system diagram of an example of a rotating recording medium reproducing apparatus. The reproduced signal from the disk 30, which is read by the scanning needle 40 as a slight change in capacitance using a known technique, is sent to a preamplifier 41 having a resonant circuit whose resonant frequency changes according to the change in capacitance. After being supplied with a signal of a desired level, it is divided into two parts, one of which is outputted from an output terminal 42 to a demodulator (not shown) to reproduce the main information signal, and the other is outputted to a low-pass filter 43 as shown in FIG. Frequency components lower than the main information signal recording band shown are separated and then supplied to the AGC circuit 44. The above-mentioned low-pass filter 43 is an AGC circuit 44
The reference signals f P1 , f P2 , and f P3 are adjusted so that only the required frequency components of the reference signals f _P1 , f _P2 , and f _P3 are transmitted so that they are not affected by the playback level or frequency characteristics of the main information signal in the playback signal. Provided to separate the signal from the main information signal.

By the way, the reproduction signal from the preamplifier 41 is
The radial position of the disk 30, subtle changes in the contact situation between the surface of the disk 30 and the electrodes provided on the scanning needle 40, dust adhesion to the sliding surface of the scanning needle 40, replacement of the disk, and further contact situations, etc. This is accompanied by a change in the reproduction level due to subtle changes over time, etc., and along with this, the reference signals f _P1 , f _P2 ,
f _P3 is also accompanied by fluctuations in the playback level from time to time, and if this was directly converted into DC error power and applied to the drive mechanism of the scanning needle 40, the servo loop gain would constantly change with changes in the playback signal level. As a result, stable tracking servo cannot be applied, the servo loop is disturbed, and mistracking occurs.

Therefore, before discriminating and separating each of the reproduced reference signals and applying them to the differential amplifier, the AGC circuit 44
is provided so that the reference signal level is always kept at a predetermined level and the above-described change in the reproduced signal level is corrected. However, tracking control reference signal
Since the playback levels of f _P1 and f _P2 change according to the tracking deviation, it is necessary to detect this change and perform tracking control.
The AGC circuit 44 must be configured so that the sum of the respective reproduction levels of f _P1 and f _P2 always remains at a predetermined constant level.

The output signal of the AGC circuit 44 is simultaneously supplied to band filters 45, 46 and 47 having center frequencies of steep passbands f _P1 , f _P2 and f _P3 , respectively. As shown in FIGS. 7A and 7B, the output reproduction reference signals f _P1 and f _P2 of the band filters 45 and 46 are continuously output during reproduction of the disk 30, and are adjusted to predetermined levels by variable resistors 48 and 49, respectively. and is supplied to the polarity switching circuit 50 so that, at least during normal playback, it is generated based on the position shown at 32 in FIG. A switching pulse is applied from the input terminal 51, and switching of f _P1 and f _P2 is performed every rotation period of the disk 30.
Here, as mentioned above, the disk rotation speed
Since the rotation speed is 900 rpm, two frames of video signals are recorded for one rotation of the disk, so the polarity switching circuit 50 sends the seventh signal to the detection circuit 52 by a polarity inversion switching pulse every two frames (1/15 seconds). The signal shown in Figure C is supplied to the detection circuit 53 as a signal shown in Figure D.

Thus, the above switching pulse can be obtained from the reference signal f _P3 recorded on the disk 30 corresponding to the switching recording position of f _P1 and f _P2 . That is, the third reference signal f _P3 shown in FIG. 68 to trigger it. The output of flip-flop 68 is applied to input terminal 51 via output terminal 69.

Note that in this case, signal loss from the scanning needle 40,
In order to prevent the influence of noise etc. and obtain a more stable and reliable switching pulse at terminal 69,
A flywheel oscillator that oscillates at 15Hz,
Or, it is more desirable to configure an AFC circuit or the like to perform a similar role and apply it to the flip-flop 68.

The detection circuits 52 and 53 convert the input reference signals into DC voltages and supply them to respective input terminals of the differential amplifier 54. The differential amplifier 54 compares and contrasts the output signals of the reference signals 52 and 53, which vary according to the reproduction levels of f _P1 and f _P2 , and outputs a tracking error signal corresponding to the direction and amount of deviation of the track, and outputs a tracking error signal corresponding to the direction and amount of deviation of the servo. The signal is supplied to a comparative compensation circuit 56 and a differential compensation circuit 57 through a variable resistor 55 that adjusts the loop gain of the entire loop. The signals that have undergone predetermined characteristic compensation in these compensation circuits 56 and 57 are as follows:
Variable resistors 58, 5 for adjusting respective gains
9 to the control power amplifier 60, where the power is increased to a predetermined level, and then applied from the output terminal 61 to the moving mechanism element of the scanning needle 40, so that the scanning needle 40 can be stably tracked in a closed loop.

When the cantilever device for signal tracking in a rotary recording medium playback device previously proposed by the present applicant in Japanese Patent Application No. 58-46781 is applied as the above-mentioned moving mechanism element, Tracking control can be performed more stably and with high precision. That is, one end of the scanning needle 40 is fixed to the free end of a cantilever 62 fixed to a bracket 64 via a damper 63, and is disposed so as to extend in the same direction as the longitudinal direction of the cantilever 62. Permanent magnet 6 magnetized in the horizontal direction
5 in the perpendicular direction around the cantilever 18 and the control power from the output terminal 61 applied to the conductive wire 66 fixed to the top of the cantilever 62 in the axial direction thereof.
The cantilever 62 is driven and displaced in a direction perpendicular to the track scanning direction, and the scanning needle 40 is tracked accordingly.

As the scanning needle 40, for example, one having a needle structure as shown in FIG. 8, which was previously disclosed by the present applicant in Japanese Patent Application No. 127767/1982, is used, in which the electrode width dimension does not change even when wear progresses. It is more desirable to do so from the viewpoint of the life of the scanning needle and the disk surface.

Note that during still image playback, the switching pulse from the output terminal 69 shown in FIG. 6 (or the output of the detection circuit 67) is waveform-shaped and becomes two frames of the recorded video signal (shown in V units in FIG. 9A). Pulse (9th pulse) output corresponding to position 32 every cycle
This is applied to the differential compensation circuit 57 from the input terminal 70 as a timing pulse (kick pulse) for the kickback operation, for example. In practice, the polarity of the kick pulse during still image reproduction is selected by taking into account the control polarity of the servo system and the scanning needle moving mechanism, and the polarity of the kick pulse is selected so that the jump deviation amount is exactly one track pitch. By setting the amplitude and pulse width in advance, a desired still image can be reproduced.

In addition, when performing slow motion playback at an arbitrary speed ratio, for example, when performing slow motion playback at 1/7, the speed at which the scanning needle 40 is moved in the radial direction of the disk 30 is reduced to 1/7 of that during normal playback. In connection with deceleration, a kick pulse is applied to the input terminal 70, and the switching pulse applied to the input terminal 51 during normal reproduction is counted down to 1/7 and applied to the input terminal 51. That is, the switching pulse is counted down to 1/7 to form a pulse as shown in FIG. 9C, and is applied to the polarity switching circuit 50 from the input terminal 51. At the same time, a kick pulse as shown in FIG. 9D is applied to the input terminal 70 so that the scanning needle 40 repeatedly reproduces the same track seven times. This gives 1/
7 can be played in slow motion.

When advancing the scanning needle 40 to the next track after repeated reproduction a predetermined number of times, the polarity of the switching pulses for f _P1 and f _P2 is reversed at the switching position 32, and the application of the kickback pulse to the terminal 70 is stopped. do. Furthermore, during first motion reproduction, the kick pulse has a polarity that causes the scanning needle 40 to kick in the forward direction by one track pitch. In addition to the above, special playback such as reverse playback and high-speed playback can also be performed as desired.

Application Example The track pattern of the disk to be recorded is not limited to those shown in FIGS. It can also be applied to pattern recording.

Further, the main information signal to be recorded is not limited to a video signal, but the present invention can also be applied to a master disk of a rotating recording medium in which an audio signal is recorded as a high-quality, multi-channel audio signal with a high dynamic range.

In addition, although the case where a single frequency is used for f _P1 and f _P2 has been described above, for example, a signal obtained by FMing an audio signal and recording it continuously is used as the reference signal f _P1 ,
f Can be appropriated as _P2 . Furthermore, it is also possible to perform a modification such as frequency-converting the carrier color signal in the color video signal to a lower frequency band using a well-known technique and applying it to the reference signals f _P1 and f _P2 . In short, the reference signal only needs to be recorded and reproduced in a signal form that can at least be used for tracking control.

Effects As described above, according to the present invention, since the main information signal and the tracking control reference signal f _P1 or f _P2 are simultaneously recorded by the first and second modulated beams, the main information signal is the tracking control signal. It is possible to record continuously without signal loss even during recording, and since the light intensity of the two types of modulated beams can be adjusted independently of each other, the main information signal recording pit can be adjusted so that the reproduced signal is optimally obtained. The column and tracking control reference signal recording pit examples can be recorded with the optimum depth and width, respectively, and the two types of tracking control reference signals f _P1 and f _P2 can be mutually switched for each rotation period of the master disc. Therefore, the first tracking control reference signal is always recorded on the outer side of the sub-tracks on both sides of the main track, and the second tracking control reference signal is always recorded on the inner side. This has the advantage that the recording density of the main information signal can be increased compared to the case where the main information signal is recorded.

[Brief explanation of the drawing]

FIG. 1 is a block system diagram of an embodiment of the recording method for a master disk of a rotating recording medium according to the present invention, and FIG.
FIGS. A to D and FIGS. 3 A to D are respectively signal waveform diagrams for explaining the operation of FIG. 1, and FIG. 4 is a diagram showing an example of the frequency spectrum of a recording signal by the recording method of the present invention.
5A to 5D are partially enlarged plan views of track patterns of examples of rotary recording media recorded by the method of the present invention, and FIG. 6 is a block system diagram of an example of an apparatus for reproducing a rotary recording medium. 7 is a signal waveform diagram for explaining the operation of FIG. 6, FIG. 8 is a diagram showing an example of the scanning needle shape previously proposed by the applicant, and FIGS.
D is a signal waveform diagram for explaining the operation of FIG. 6, respectively. 1, 22... Laser light source, 4... Video signal input terminal, 6, 14... Light beam modulator, 10,
11, 12... Reference signal oscillator, 13, 24...
Synthesis circuit, 17... Polarizing prism, 19... Objective lens, 20a... Substrate, 20b... Photosensitive agent, 2
1... Recording master, 30... Disk, 40... Scanning needle, 41... Preamplifier, 43... Low-pass filter, 44... AGC circuit, 45, 46, 47...
Band filter, 50...Polarity switching circuit, 54...
...Differential amplifier, 62...Cantilever, 67...
Detection circuit, 68...Flip-flop.

Claims (1)

[Claims] 1. While rotating a master disc of a rotating recording medium having a photosensitive agent coated on a substrate, first and second reference signals having different frequencies in a frequency range lower than the recording frequency range of the main information signal are transmitted to the master disc. 1
The reference signals are alternately switched and arranged alternately in time series for each rotation period, and the positions related to the switching of the first and second reference signals are provided at predetermined positions corresponding to one rotation period of the master. a first modulated beam obtained by modulating a light beam with the main information signal or a multiplexed signal of the main information signal and the third reference signal; A composite signal of the arranged reference signal and the third reference signal generated only in a predetermined period, or a second signal obtained by modulating a light beam with the alternately arranged reference signal.
The first and second modulated beams are irradiated and recorded at the same time on the photosensitive material of the master at a distance of about 1/2 track pitch from each other, and then the master is developed and the first modulated beam is placed on the substrate of the master. A spiral or concentric pit row formed by the second modulated beam is recorded as a main track, and a spiral or concentric pit row formed by the second modulated beam is recorded approximately in the middle between the track center lines of the main track. A recording method for a master of a rotating recording medium, characterized in that a pit row of a track is recorded as a sub-track.