JPH02257443A - Information recording medium having track to be asymmetrically oscillated, manufacturing device for the same and information recording and/or reproducing device using the same medium - Google Patents

Abstract

PURPOSE:To record information with a correct sequence and high accuracy and to exactly read the information by making one period of oscillation asymmetric in the meaning that the oscillation in the latter half of the period is not made reverse to the oscillation in the beginning of the period in a data medium having a groove. CONSTITUTION:A groove 24 is a tracking groove having a certain asymmetric oscillating waveform formed on a data medium 13 in the mastering of the data medium 13. In the reading and writing of the information, the spot of energy beam is projected along the information groove 24 formed on the data medium 13 and reflected light or transmitted light is detected by an optical detector 28 in the form of an electric signal. Then, a synchronizing signal is detected. This signal is rectified and off-set between the optical spot and information groove 24 is detected. After the off-set is detected by an off-set detector 31 and corrected, the information are written and read on the groove 24. Thus, the information can be exactly written, read or repro duced with the correct sequence.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data medium for recording and reproducing information using an energy beam, and an apparatus for manufacturing the medium. The present invention also relates to a device for recording information on the medium, a device for reproducing information recorded on the medium, and a device for performing the recording and reproduction.

[Conventional technology]

In the past, many proposals have been made for methods of ensuring accurate tracking of an energy beam (hereinafter referred to as a working beam or light beam) on a high-density data medium, such as an optical disc or a video disc. .

One method utilizes a portion of the working beam that is reflected by the data medium and measures the energy incident on a detector with two or more suitably arranged pickups. The tracking signal is measured by the relative intensity of energy incident on such a detector. A disadvantage of this method is that tracking offsets due to, for example, tilting of the data medium cannot be detected. Furthermore, if there is, for example, thermal expansion or a defect in the shape of the information groove on the medium, it is likely that the pickup will be misadjusted and tracking will become impossible.

Another method uses special marks formed on the information grooves of the data carrier and measures the tracking offset by comparing the reflection intensities measured at the marks.

The disadvantage of this method is that since tracking offsets are detected only at positions where marks are placed, offsets cannot be detected at positions between marks.

In the third method, the position of the working beam is oscillated on the data medium, the intensity time dependence of one reflected light is measured, and the tracking offset is measured from the time dependence. The disadvantage of this method is that the oscillations of one working beam must be very fast, which is technically very difficult to implement.

A fourth method uses symmetrically vibrated information grooves on the data carrier to measure the time dependence of the reflected intensity of the working beam. In order to measure the tracking offset from its time-dependent function, it is necessary to detect the phase of its vibration, i.e. the direction of the offset.1 To detect the phase.

A reference frequency is written onto the data medium along with the data.

It is therefore only applicable to lead-on type data media.

Otherwise, the reference phase has to be written on the data medium even when no user information is present on the data medium, which is very cumbersome and requires reference frequency and data image information. must be stored on a data medium, and the storage capacity available to the user is necessarily reduced.

Furthermore, examples of prior art related to the present invention include the following.

U.S.P., No. 3,860,766, U.S.P.
No. 3.931460.

US Patent No. 4,223,187 9 Japanese Patent No. 981,9
78 No. 2 Japanese Patent 1,277.006. JP-A-63-4
3812゜[Problems to be Solved by the Invention] The present invention provides a data medium having an information groove, particularly an optical disk, in which information can be recorded on the medium in the correct sequence and with high precision, or as described above. Recorded information can be accurately read from the medium.

It was created for the purpose of providing a data medium.

Another object of the present invention is to provide an apparatus for manufacturing the above-mentioned medium.

Still another object of the present invention is to provide a recording device for easily and accurately writing information on the above-mentioned medium, a reproducing device for easily and accurately reading information from the above-mentioned medium, or a device for both recording and reproducing. The object of the present invention is to provide a recording and reproducing device that can perform the following functions.

[Means to solve the problem]

In the present invention, in order to solve the above problems, an information groove that vibrates (meanders) according to a special function is formed on a data medium. This groove is formed on the data medium during mastering of the data medium. A tracking groove with a certain asymmetrical vibration waveform. Here, the above-mentioned spoofed vibration waveform means that within the plane of the data medium, the displacement of the center line of the information groove changes periodically in a direction perpendicular to the direction along the information groove, and the displacement after half a period It means that the amount is asymmetric in that the amount of displacement does not take the opposite value of the initial amount of displacement.

[Effect]

In reading and writing information, a spot of an energy beam is applied along an information groove formed on the data medium and the reflected or transmitted light is detected in the form of an electrical signal. A synchronization signal is detected from the detected signal. The synchronization signal rectifies the detected signal and the offset between the light spot and the information groove is detected. Writing or reading information on the groove is done after detecting and correcting the offset.

In short, in the present invention, the signal for offset detection can be obtained only from the vibrated information groove. When reading and writing information, tracking deviations can be recovered from the reference signal and the signal from the beam reflected from the information groove formed by vibrating according to the present invention.

〔Example〕

The present invention will be more clearly understood from the following examples, which are explained with reference to the accompanying drawings.

FIG. 1 shows a schematic configuration of an apparatus for producing a data medium according to an embodiment of the present invention, that is, an apparatus for forming an information groove length according to the present invention on a data medium represented as an optical disk. .

Referring to FIG. 1, there is shown one embodiment of an apparatus for writing information grooves in vibrating form on a high density data medium, such as an optical disc. The medium 1 has a central axis 2, as indicated by arrow 3.
is rotated around.

Parallel light (collimated light) 5 from a light source 4 forms a minute spot 8 on the surface 9 of the photosensitive material covering the disc.
is guided by a light deflecting means 6 (which consists of a mirror 6' and a drive 6' driving the mirror 6') to a condenser (lens) 7 forming a light beam.

The spot 8 is moved from the outside of the disc to the inside as the disc rotates, so that one continuous track 10 is formed.

In order to vibrate the track 10, the oscillator 11 oscillates at a frequency f. The signal from this oscillator is modulated by a modulator 12 according to the invention, from which the modulated signal obtained is fed to a drive device 6' for correctly driving the mirror 6'.

FIG. 2 shows an embodiment of an apparatus for writing information on a high-density data medium with vibrating information grooves according to the invention. , as indicated by arrow 15,
Rotates around a central axis 14. Collimated light 16 from light source 17 enters light modulation means 18 . Light modulation means 18
is driven by a modulator 1I 119 that modulates the light beam 16 according to information from the information source 20. The brightness-modulated light 21 is guided by a light deflecting means 22 (consisting of #122' and a driving device 22' for driving the mirror 221),
A small spot 24 is formed by a condenser lens 23 on the reflective surface 25 of the photosensitive material covering the disc.

As the disk 13 rotates, the spot 24 moves along an information groove 26 formed according to the invention. A portion of the light reflected by the reflective surface 25 is detected by a photodetector providing an electrical signal 29. The means 28 are guided by a light guide 27 .

This signal 29 is vibrating in accordance with the vibration of the track 26. This signal is demodulated by a demodulator 30, and an offset detector 31 detects whether the optical spot 24 is located at the center of the information groove 26 or offset, and to which side its direction is shifted. . The detected offset is corrected by a drive 22' which drives mirror 22''. Possible detection mechanisms will be explained in detail in connection with FIGS. 6-8.

FIG. 3 shows an embodiment of an apparatus for reading information from a high density data medium having vibrated information grooves according to the invention.

For example, the high-density data medium 32 consisting of an optical disk is
It rotates about a central axis 33, as indicated by arrow 34. The collimated light 35 from the light source 36 is
A condensing lens 388 is guided by the light deflection means 37 (comprised of a mirror 37' and a drive 37' for driving the mirror 37') and a microscopic light is directed onto the reflective surface 40 of photosensitive material covering the disc 32. A spot 39 is formed.

As the disk rotates, the spot 39 moves along a vibrating information groove 41 formed according to the invention. A portion of the light reflected by the reflective surface 40 provides an electrical signal 44. To the light detection means 43, the light guide 4
Guided by 2.

This signal 44 includes both the data read from the information groove 41 and tracking information. The vibration frequency of the information groove 41 is set so that the average frequency of the data is much higher than the vibration frequency of the information groove 41, and the two signals are separated by the frequency filter 45.

One output of the frequency filter 45 is a high frequency component received by the photodetection means 43 and becomes a data signal 46. Further explanation of the data signals is omitted as it is not important to the disclosure of the present invention.

The other output of the frequency filter 45 is the low frequency component of the signal received by the photodetection means 43 and becomes the tracking signal 47.

This signal 47 oscillates in accordance with the oscillation of the information groove 41 formed according to the invention. The signal 47 is demodulated by a demodulator 48, and an offset detector 49 detects whether the light spot 39 is in the center of the information groove 41 or in which direction it is shifted due to its offset. This detected offset is corrected by drive 37' which drives @37'. Possible detection schemes will be explained in detail in connection with FIGS. 6-8.

FIG. 4 shows a portion of an information groove vibrated in accordance with the present invention. Here, in order to clearly show the characteristics, the information groove 50 has unequal magnification in the horizontal and vertical directions.
has a certain width.

When creating a data medium, set the center of the light spot 51 to 2
By vibrating along the dot chain 52, an information groove 50 that vibrates as shown in the figure is formed.

The center of vibration of the information groove 50 is indicated by a solid line 53. When reading and writing information, the optical spot 51 is
It is accurately tracked along line 53.

T is the period of vibration. The information groove 50 is oscillated so that it has a certain asymmetry, so that, mathematically speaking, the vibration function f does not follow the following equation.

f (t+t/2)=-f (t)
(1) In the example shown in Figure 4, the information is
The following function, namely f(t)=sin(k t)+1/2sin(
2k t) is vibrated according to (2).

FIG. 5 shows one information groove vibrated by the present invention to a second
The signals detected by the photodetection means 28 or 43 of FIG. 3 and FIG. 3 are shown.

The solid line 54 in FIG. 5 represents the light spot 51 in FIG.
represents the signal detected when it follows the solid line 53, that is, when it has the center of the information groove 50.

The dashed line 54' indicates that the light spot 51 corresponds to the dashed line 53' in FIG.
, that is, when it is located above the center of the information groove 50 .

The dash-dotted line 54' is received when the light spot 51 follows the dash-dotted line 531 in FIG. 4, that is, when it is located below the center of the information groove 50.

Since the delay times T' and T' are different, the degree of displacement from the center of the track, that is, the offset is determined.

The detection of the difference can be done based on the vibration function f, and several different schemes are possible. In the following, three possible evaluation methods are described.

In FIG. 6, the information groove swings once in each direction per cycle. A typical evaluation method that can be applied to an example having the vibration locus shown in No. 5rR is shown. Signal 55 from the light detection means 28 or 43 of FIG. 2 or 3
is divided into two branches 55' and 551. Signal 55' is fed to a peak detector 56, such as a threshold switch. If the peak detector 56 detects the signal 55
When a peak is detected at
(58a, 58b) is triggered.

If a trigger pulse arrives, storage element 58b will take over the value previously stored in storage element 58b, and storage element 58a will take over the new value given by signal 55''. The signal is provided to a differential amplifier 60. The output of differential amplifier 60 provides the absolute value of the tracking offset signal.

Peak detector 56 triggers clock 57 to determine the sign of the tracking offset. The time delay t since the last trigger pulse is compared in window comparator 59 with the time T' shown in FIG. If the delay times defined by the clock and the time T' are equal or at least equal to f (this corresponds to the initial falling and subsequent rising oscillations in FIG. 4), the comparator 59 detects the tracking value 6 for offset
Triggers the gate 61 that allows 2 to pass through.

Otherwise, it is because it inverts the tracking signal 62 that the tracking error signal 63, which is not supplied as is, is supplied as a second signal in order to correct its offset.
A light deflection means 64 is provided for deflecting the light beams 21 and 35 in FIGS.

A second possible vibration function is shown in FIG. In (this), only the function of the track shape is shown, rather than the entire track shape, to simplify the explanation. ) This vibrational function is expressed by the following equation: f (t) = sin (kt) +
5in (3/2k) = 2 cos (kt/4) 5
in (5kt/4) (3) Two vibrations with the same strength but slightly different frequencies create a beat both in the information groove and in the received signal.

An embodiment of the tracking method using this type of vibration information groove is shown in FIG. 7, and the optical detection means 2 of FIG. 2 or 3
The signal 65 supplied by 8 or 43 is split into two branches 65' and 65'. One branch 65' is fed to a bandpass filter 66 which passes only one suitably selected frequency. From this frequency, the information groove 2 of FIG. 2 or FIG.
Phase information of vibrations 4 and 39 is retrieved. Oscillator 67
is triggered by this information, and the signal is sent to multiplier 68
In , the output of zero multiplier 68, multiplied with signal 65' from another branch of signal 65, is proportional to its tracking offset.

The tracking error signal 69 is transmitted to the light beams 21 and 35 of FIGS.
is defined as a supply to the light deflecting means 70 which deflects the light.

As is clear from FIG. 9, FIG. 8 shows the signals supplied by the photodetection means 28 and 43 of FIGS. A second tracking method for evaluating .

The signal 71 has three branches 71-1, 71-2 and 71
−3. Branch 71-1 is a bandpass filter 72-1 that passes only one appropriately selected frequency.
supplied to. From this frequency, phase information of this frequency is retrieved.

Branch 71-2 is fed to a bandpass filter 72-2 which passes only suitably selected further frequencies. From this frequency, the phase information of that frequency is retrieved.
The phase information of the vibrations 41 and 41 is retrieved by comparing the phases of the image frequencies. This comparison is performed in a coincidence detector 73 whose signal triggers an oscillator 74.The signal from oscillator 74 is multiplied in a multiplier 75 with the signal 71-3 from the third branch of signal 71. .

I'm giving an example. The tracking error signal 76 is fed to light deflection means 77 which deflects the light beam 21 or 35 of FIG. 2 or 3 in order to correct its offset.

In all the above cases, the process of extracting the in-phase component is unaffected by the noise of the stray light by setting its oscillation frequency to be higher than the frequency of the noise of the stray light; A good quality tracking signal can be obtained.

In the above embodiments, the information reproducing device was described as one that detects reflected light, but it goes without saying that it may also be configured to detect light. In its place, an optical system for focusing light and a mechanism for moving it are required in the direction of incidence of the working beam and on the complete side with the optical disk in between.

〔Effect of the invention〕

As described in detail above, according to the present invention, information can be accurately written in the correct sequence on a high-density data medium, especially a data medium such as a video disk or an optical disk, using low-cost recording and reproducing equipment. It can be read and played.

Furthermore, the method and apparatus disclosed herein are not limited to the field of optical working beams, but are also applicable to other types of high density recording, such as e.g. electron beam recording.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the general configuration of a data medium manufacturing apparatus according to an embodiment of the present invention. FIG. 2 shows an arrangement according to the invention for writing information on a data medium, which is shown as an optical disc. FIG. 3 shows an arrangement according to the invention for reading information from a data medium, which is shown as an optical disc. FIG. 4 shows an information groove vibrated according to the invention. FIG. 5 shows a signal received from a vibrated information groove in accordance with the present invention. FIG. 6 shows one evaluation circuit for the received signal. FIG. 7 shows another evaluation circuit for the received signal. FIG. 8 shows a third evaluation circuit for the received signal. FIG. 9 shows another information groove vibrated according to the invention. Explanation of symbols 1.13.32...Data medium (optical disk) 2゜1
4.33...Rotation axis, 4,17,36...Light source, 5
゜16.35...Working beam, '6,22.37,6
4゜77...Light deflection means, 7,23.38...Concentrator, 8゜24.39...Beam spot, 9,25,
40... Reflective surface, 10, 26.41... Information groove, 1
1.74... Oscillator, 12.19... Modulator, 18
...Light modulation means, 20...Information source, 27.42...
・Light guide, 28°43...Photodetector, 30.48・
...Demodulator, 31...Offset detector, 45...
Frequency filter, 56...Peak detector, 58a, 5
8b...Storage device, 59...Comparator, 60...Differential amplifier, 61...Gate, 72-1.72-2...
- Bandpass filter, 75...multiplier. 2nd λr X Noda 7th $ 3 Country 4th Evening Eye 7th Figure

Claims (1)

[Claims] 1. In a data medium having a groove, the groove oscillates minutely and periodically in the plane of the data medium orthogonal to the direction of the groove, and one period of the oscillation is A data medium characterized in that it is asymmetric in the sense that the oscillations in the second half of the period are not opposite to the oscillations at the beginning of the period. 2. The oscillation of the asymmetric groove has only one peak in each direction, and the asymmetry of the oscillation is implemented by a delay between two peaks that is not equal to the period of the period. Data medium according to item 1. 3. The data medium according to claim 1, wherein the asymmetry of the oscillation of the groove is created by oscillation of not only one but two or more frequencies. 4. Data carrier according to claim 1 or 3, characterized in that the frequencies interact in such a way that their fundamental frequency is directly provided by their interaction. 5. Data medium according to claim 1 or 3, characterized in that the frequencies interact in such a way that their fundamental frequency is not directly provided by their interaction. 6. Data medium according to any one of claims 1 to 3, characterized in that the frequencies are chosen such that the lowest frequency used is greater than the servo band frequency. 7. Data medium according to any one of claims 1 to 3, characterized in that the frequencies are chosen such that the maximum frequency used is smaller than the data band frequency. 8. The frequencies are selected such that the minimum frequency used is greater than the servo band frequency and the maximum frequency used is smaller than the data band frequency. A data medium as described in . 9. The data medium according to claim 1, wherein the data medium is an optical data medium. 10. The data medium according to claim 1, wherein the data medium is an optical disc. 11. Data medium according to any one of claims 1 to 8, characterized in that the data medium is an optical drum. 12. Data medium according to any one of claims 1 to 8, characterized in that the data medium is an optical tape. 13. The data medium according to any one of claims 1 to 8, characterized in that the data medium is an electronic data medium. 14. The data medium according to any one of claims 1 to 8, characterized in that the data medium is an electronic disk. 15. Data medium according to any one of claims 1 to 8, characterized in that the data medium is an electronic drum. 16. The data medium according to any one of claims 1 to 8, characterized in that the data medium is an electronic tape. 17. Apparatus for producing a data medium according to any one of claims 1 to 16, comprising: an energy source for emitting a collimated energy beam; deflection means for deflecting the energy beam onto the data medium; means for guiding the beam onto the deflecting means; and further energy focusing means for focusing the energy beam onto a data medium, the data medium being continuous relative to the energy beam provided by the energy focusing means. and an oscillator that vibrates at a constant frequency.
8, and a drive device that drives the deflection means according to the signal supplied by the modulator. device to do. 18. Claim 17, characterized in that the energy source is a laser, the energy beam is a laser, and the data medium is an optical data medium, such as, for example, a disk, tape or drum. The device described. 19. The energy source is an electron gun, the energy beam is an electron beam, and the data medium is
18. Device according to claim 17, characterized in that it is an electronic data medium, for example a disk, tape or drum. 20. A device for producing a tracking error signal from a grooved data medium according to any one of claims 1 to 16, in which a light beam is directed onto the grooves on the data medium and its reflected secondary light is It is characterized by comprising means for extracting a synchronization signal from an electrical signal obtained by conversion by a photoelectric conversion means, and means for adjusting an envelope signal of the electrical signal by using the synchronization signal. A device that does this. 21. Apparatus according to claim 20, characterized in that said synchronization signal triggers two signal storage means for storing two signals derived at different times, the difference of said signals giving its tracking offset. 22. The periodic signal triggers an oscillator, further comprising multiplication means for multiplying the signal from the oscillator with the electrical signal derived by the photodetection means, the signal obtained by the multiplication means being 21. Apparatus according to claim 20, characterized in that it provides a tracking offset. 23. The synchronization signal is derived by detecting special properties of the signal obtained by the photoelectric conversion means, such as, for example, minimum or maximum values in the signal or derived values derived therefrom. 23. Device according to any one of claims 20 to 22, characterized in that: 24. According to any one of claims 20 to 22, characterized in that the synchronization signal is derived by filtering a suitably selected frequency of the signal obtained by the photoelectric conversion means and detecting its phase. The device described. 25. characterized in that the synchronization signal is derived by filtering one or more suitably selected frequencies of the signal obtained by the photoelectric conversion means, detecting and comparing their relative phases; 23. Apparatus according to any one of claims 20 to 22. 26. Apparatus for recording information on a data carrier according to any one of claims 1 to 16, comprising: an energy source emitting a collimated beam of energy; input means for information; and an apparatus for recording information on a data carrier. intensity modulation means for modulating said energy beam according to information to be transmitted; and energy deflection means for guiding said energy beam onto a data medium according to any one of claims 1 to 16, arranged in the path of said energy beam. and energy focusing means for focusing the energy beam onto the data medium, the data medium being moved continuously relative to the energy beam provided by the energy focusing means. , further comprising a beam splitter arranged in the path of the light reflected by the data carrier, the reflected light being modulated by grooves and written information according to claims 1 to 8. a device according to any one of claims 20 to 25, comprising: optical detection means for detecting a modulated signal derived from said data carrier; and said deflection means for correcting a detected tracking offset. A device characterized in that it is equipped with a drive device that drives the. 27. A device for reproducing information written on a data medium according to any one of claims 1 to 16, comprising an energy source emitting a collimated energy beam; energy deflection means arranged in the path of said energy beam to focus said energy beam onto said data medium, said data medium comprising: a beam splitter adapted to be continuously moved relative to the energy beam provided by the energy focusing means and arranged in the path of the light reflected by the data medium; , the reflected light is adapted to be modulated by the groove according to claims 1 to 8 and the information written thereon, further comprising detecting a modulated signal extracted from the data medium. a device for separating said data signal from its tracking signal; a device according to any one of claims 20 to 25; and a drive device for driving said deflection means to correct a detected tracking offset. A device characterized by comprising: 28. Apparatus for recording and reproducing information on a data medium according to any one of claims 1 to 16, comprising: an energy source emitting a collimated beam of energy; an input for information; Intensity modulation means for modulating said energy beam in accordance with the information to be placed on said data carrier in the case of recording information; and energy modulating means for guiding said energy beam to a data carrier according to any one of claims 1 to 16. deflecting means and energy focusing means arranged in the path of the energy beam for focusing the energy beam onto the data carrier, the data carrier being arranged in the path of the energy beam to focus the energy beam onto the data carrier. 8. A beam splitter adapted to be moved in relative succession and further arranged in the path of the light reflected by the data carrier, wherein the reflected light is transmitted in accordance with claims 1-8. and the information written in accordance with the information to be recorded when recording information or the information written on it when reproducing information,
26. Any one of claims 20 to 25, further comprising optoelectronic means for detecting a modulated signal derived from said data medium and a device for separating said data signal from said tracking signal.
and a drive device for driving said deflection means in order to correct the detected tracking offset thereof. 29. The energy source is a laser, the energy beam is light, and the data medium is an optical data medium, such as an optical disk, an optical tape or an optical drum. Any one of claims 26 to 28
Equipment described in. 30. The energy source is an electron cathode, the energy beam is an electron beam, and the data medium is an electronic data medium such as an electronic disk, an electronic tape, or an electronic drum. 29. A device according to any one of claims 26 to 28.