JPS60167129A - Recording carrier and information processing device - Google Patents

Abstract

PURPOSE:To insert a pilot signal to main information by recording a phase discriminating signal for tracking control of an optical disc while changing the depth of grooves of pits of a main information signal or a guide track. CONSTITUTION:Recording pits are recorded while wobbling at a period of an amplitude shorter than the pit width. The pit depth is switched to d1 and d2 synchronously with the period of wobbling as shown by a figure (a). At this time, a track is scanned with a light spot, and directions of reproduced outputs in areas having the pit depth d1 and areas having the pit depth d2 are reverse to each other with centers of pits as O in a differential output (d) of detectors 6-1 and 6-2 which are divided into two in the scanning direction. An output (c) of an adder is the main information signal. This signal is taken out by a band-pass filter and is processed in a synchronous detecting circuit 14 together with a phase detecting signal (g).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an information processing device that reads information by irradiating an information track of a record carrier with a light beam, and a record carrier thereof.

[Background of the invention]

When recording and reproducing information using an optical disk or the like formed in the shape of a track, it is necessary to perform tracking control to follow the track.

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μ/711-: Record the 'l no 1 in a state of slight vibration in a direction perpendicular to the track scanning direction at a certain constant frequency, and include a pilot signal for distinguishing the direction of vibration in the information signal, During playback, the center deviation of the track is detected using the envelope minute vibration component of the playback signal, and the tracking control of the optical spot is performed.
The briwbling method is known. (For example, see Japanese Patent Publication No. 54-15727.) This method does not require extra optical parts or other actuators for detecting control signals in the playback device, so the playback device is simple and easy to use. be. However, since this method requires synchronous detection of minute vibration components, there are restrictions in that a pilot signal must be included in the main information signal or a synchronization signal of the main information signal must be used. As a result, the main information is limited and a single frequency signal cannot be reproduced. In the case of a recording/reproduction type optical information disc system, it is more convenient to prepare a guide track on the disc in advance, and it is necessary for the optical spot to track and record the guide track.

However, in order to perform tracking using this buri-wobbling method, it is necessary to insert a pilot signal for phase discrimination of minute vibrations into the guide track in some form. Until now, there was no suitable method.

[Purpose of the invention]

The present invention has been made in view of this point, and provides a recording medium and an information processing device that can record a phase discrimination signal without limiting the main information signal or the guide track.

[Summary of the invention]

In order to achieve such an object, the present invention uses a wobbling phase discrimination signal as a main information signal or a guide track pitch 1 signal.
-・It is characterized by recording by changing the depth of the groove.

[Embodiments of the invention]

This will be explained in detail below using the drawings. FIG. 1 shows an outline of an optical information processing device using the present invention. The information surface of the disc 1 has track-shaped irregularities called pits. A light beam from a light source 2 such as a laser is passed through a lens 3. The light passes through a half mirror 4 and is focused on the information surface of the disc 1 by a diaphragm lens 5. The reflected light modulated by the pits is reflected by the half mirror 4 and converted into an electrical signal by the photodetector 6. The optical detection @6 is divided into two parts along the track direction,
This shows that the amount of reflected light can be captured by the adder 7 and the subtractor 8, respectively. Main information is sent from terminal 9 to adder 7
It can be obtained as the output of Next, the present invention will be explained with reference to FIG. 2, which shows the bit shape of the disk and its reproduced waveform. In the present invention, in order to obtain the j~ racking detection signal,
The recording bits are wobbled and recorded in advance at a period with a width smaller than the pit width. FIG. 2(b) shows a state in which pits are periodically wobbled in a direction perpendicular to the track scanning direction. Further, the record carrier used in the present invention records the bit depth in two stages, ie, a dl area and a d2 area, as shown in FIG. 2(a), in synchronization with the wobbling cycle.

When we change the phase depth and optical depth of the pit (its planar shape is shown in Figure 2(b)) and look at the distribution of the amount of reflected light, we can see that when the light spot crosses the bit,
phase depth (optical depth) is 1 of the wavelength λ of the readout light.
This is to take advantage of the reversal after /4. To explain this point in detail, in the region (a), the phase depth and optical depth) are set to be slightly less than λ/4, and in the region (b), the phase depth and the optical depth) are set to λ/4. d deeper than 4
Set it to 2. At this time, the track is scanned by the optical switches 1 to 1, and the differential outputs of the detectors 6-1 and 6-2, which are divided into two in the scanning direction, are shown in FIG. 2(d). FIG. 2(d) shows that the direction of the reproduced output is reversed between d□ and d2, assuming that the 'ψ center of the bit is O. The differential output (phase depth (optical depth)) has a peak at λ/8 and becomes zero at λ/4, resulting in 3
There is another peak at /8λ.

However, it is known that the phase of the reproduced signal is reversed when the wavelength is λ/8 and 3/8λ. Incidentally, the modulation degree is greatest when the bit phase depth (optical depth) is λ/4.

Therefore, it is preferable to set d□ and d2 to such an extent that the modulation degree does not deteriorate significantly and the differential signal (shown in FIG. 2(d)) can be detected.

A shift amount of about λ/20 from λ/4 is sufficient, and in this case, the deterioration of the main information is about 1 dB, which is no problem. FIG. 2(C) shows the output of the adder, which is the main information signal. If the spot actually deviates from the center of the track, the envelope of this waveform will be played back modulated by the wobbling frequency, and the magnitude and phase of the envelope change will be 1 to 1, indicating the deviation and direction from the track center. Therefore, this signal is extracted by a bandpass filter 13 and processed by a synchronous detection circuit 14. In addition, the signal for synchronization (shown in Fig. 2 (g)) is a differential signal that is sent to the differentiating circuit 10.
The waveform is made into a waveform as shown in FIG. 2(e), and then multiplied by the addition signal (shown in FIG. 2(C)) in the multiplier 11 to obtain the second waveform.
The waveform is as shown in figure (f), and the low-pass filter 12
You can get it through. By doing the above, the phase detection signal (g
) is a feature of the present invention.

Next, an embodiment in which recording and reproduction are performed using guide tracks will be described. When recording using a guide track, it is necessary to track the guide 1=rack and make a hole in the metal film with light. In such a case, the wobbling period can be used as a synchronization signal when recording information. By doing so, the effects of the present invention will be even greater. Therefore, recording becomes easier by setting the guide track to the same period as the clock of the recording signal. However, it should be noted that the phase depth (optical depth) of the guide track is λ
Since the value is around /4, the modulation caused by the guide track becomes too large, and there is a possibility that the S/N of the actually recorded information will be degraded. Therefore, the playback/recording slot I, which is the track IJ with the highest degree of modulation, is usually 1/3 to 1/3 of the diameter.
4 needs to be removed.

This can be narrow or wide.

An example of the structure of the guide track is shown in FIG. Figure 3(a)
3(b) shows an example of a continuous track, FIG. 3(a) is a plan view, and FIG. 3(b) is a sectional view. Guide track 2
0 is divided into two areas 20a and 20b, and recorded by wobbling in the 1-rack scanning direction, and in synchronization with this, the optical depth of the track is divided into dl (λ/4-α) and d
It is modulated to X (λ/4+α). It shows that the recording film 23 is coated on the substrate 22. For recording, six holes are made in this recording film 23 using light, for example, a hole like a circle 21 is made as shown by the broken line in the figure.

Instead, it looks like it was recorded, but this is easier to play back and causes fewer problems.

Next, examples of defective structures are shown in Figures 3(c) and 3(d).
It was shown to. This can also be recorded and played back in the same way.

Although some embodiments of the present invention have been described above, the repetition length may be an integral multiple of the synchronization, or if synchronization is not required, the cycle may be unrelated. As a further development of the present invention, inverting the wobbling phase or the depth modulation phase for each adjacent track is useful when fixing to one track or when jumping to an adjacent track. In this case, it is best to include a signal somewhere that can distinguish between tracks.

According to the present invention, since the pre-wobbling phase discrimination signal is recorded by track depth modulation, there is no restriction on the information signal or the guide track.

A highly reliable pilot signal can be regenerated.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. FIG. 2(a) is a sectional view of a record carrier used in the present invention. FIGS. 2(b) to (g) are waveform diagrams for explaining the present invention in detail, and FIGS. 3(a) to (d) are diagrams showing other embodiments of the record carrier used in the present invention. It is. Agent Patent Attorney Masaru Ogawa Oga 1 Kunisaki 2 @C9ノ

Claims (1)

[Claims] 1. A record carrier on which information is recorded or reproduced along a track by an irradiated light beam, wherein the track is minutely moved at a constant period in a direction perpendicular to the direction in which the track is formed. A record carrier characterized in that it vibrates and records are recorded in at least two regions having different depths in the track in synchronization with the minute vibrations. 2. The record carrier according to claim 1, wherein the track has an optical depth region shallower than 1/4 of the wavelength of the light beam and an optical depth region deeper than 174. A record carrier characterized by. 3. In an information processing device that records or reproduces information along the tracks of the record carrier by irradiating a light beam onto the record carrier, the tracks are minutely vibrated at a constant period in a direction perpendicular to the direction in which the tracks are formed. a two-split photodetector that converts reflected light from the record carrier into an electrical signal; and a signal obtained by differentiating the difference output of the two-split photodetector. means for multiplying by the sum output of the two-split photodetector to obtain a signal related to the depth modulation of the track; What is claimed is: 1. An information processing device comprising: detection means for synchronously detecting signals related to vibration, and controlling the irradiation position of the light beam based on the detection output.