JPS6343812B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information processing device for optically recording and reproducing digital information and the like.

For example, in an optical disk that stores digital information in a form that can be optically recorded and reproduced, grooves are provided in advance to guide the light beam spot on the optical disk in order to record additional information. An additional recording method is proposed in which information is recorded by guiding the light beam spot by relying on a guide groove (Press information Philips Nov.
7th 1978).

The present inventor has proposed an optical disc with an improved recording method in Japanese Patent Application No. 54-79210 (Japanese Patent Publication No.
No. 21386) was filed.

That is, FIG. 1 is a diagram showing the structure of an example of an optical disk filed by the present inventors.

In FIG. 1, pits in the guide groove are shown by solid lines (indicated by hunting), and pits to be additionally recorded are shown by dotted lines. The pit spacing of the guide groove is set to one additional recording pit for simplicity. The pit row of the guide groove is recorded so as to meander in the direction of movement of the groove by a minute amplitude δ at a period T, and the pit intervals are formed to have a period t.

The characteristics of such an optical disk are as follows.
That is, first, when additional recording is performed, the previously recorded pit row is meandered by a minute amplitude δ, so that the so-called pre-wobble method disclosed in JP-A-49-103515 is used. As a result, the light beam spot can perform a tracking operation that accurately tracks the pit row.
It becomes possible to record additional information pits accurately and easily.

Second, since the pit row is always reproduced at a constant period T, this type of recording/reproducing device, such as a magnetic disk or magnetic tape, can accurately record and reproduce information even when the speed of the record carrier varies. The PLL (phased lock loop) used in this product is easy to pull in and difficult to remove.

Thirdly, since the position of the pit to be additionally recorded can be determined based on the position of the pit in the guide groove, there is little timing error when reproducing information.

Fourthly, when additional recording is performed, it is usually a so-called gradation type recording in which holes are made in a metal thin film that is a recording medium. As a guide groove, the present invention can be applied to both a phase type recording form in which pits are formed in the depth direction of a recording medium and the above-mentioned shading type recording form. In particular, in the case of the light and shade type, there is no need to process the unevenness on the record carrier in advance, a flat carrier can be used, and control information such as an address can be added as desired to flexibly respond to the demands of disk users.

FIG. 2 is a diagram showing a second example filed by the present inventors. FIG. 2a shows a cross section of the recorded pit row. Numerals 1-1 to 1-5 are pits for guiding, and the depth of the pits is formed to be 1/4 of the wavelength λ of the laser beam used for reproduction. As the record carrier 2, PVC (polyvinyl chloride), which is commonly used as a replica disk, or a photoresist coated on a glass disk is suitable. FIG. 2b is a sectional view of a disk for additional recording. That is, a metal thin film 3 is formed by vapor deposition or the like on the pit row shown in FIG. 2a. Figure 2c is the second
The surface portion of FIG. b is shown, and the relationship between the guide pit and the additional recording pit is shown in the same manner as in FIG. 1. In this embodiment, the recording pit and the guide pit are approximately equal in size.

A third example filed by the present inventors is shown in FIG. The cross-sectional form of the guide pit is the same as that shown in FIG. 2a, and the creation of the additional recording disk is also the same as that shown in FIG. To make it easier to separate the pits, guide pits 5-1 to 5-5-
The size of the recording pits 6-1 to 6-10 is larger than that of the recording pits 6-1 to 6-10. By doing so, it becomes easy to separate the guide pits and the recording pits by utilizing the difference in signal level from the waveform during reproduction.

In addition, the fourth example filed by the present inventors is
As shown in the figure. The cross-sectional form of the guide pit is shown in FIG. 4a. In the figure, the depth of the pit is d. The additional recording disk is created in the same manner as in Figure 2b, but
The sizes of the guide pits 7-1 to 7-5 are made smaller than the recording pits for the same reason as in the second embodiment. In this way, the guide pit can be separated from the reproduced signal waveform. Depth d is reproduction laser wavelength λ
It may be 1/4, but 1/8 is preferable.

Furthermore, the fifth example filed by the present inventors is
As shown in the figure. The guide pits are recorded in the form of shading holes made in a thin metal film formed on the surface of the disk.
Even in this case, it is desirable to record the guide pits with relatively different sizes in order to distinguish them from the recording pits, as in the third and fourth embodiments. The guide pits 10-1 to 10-5 are recorded on the metal thin film 3 formed on the substrate 12. By recording the guide pits in a shaded manner, an additional recording disk that can be flexibly handled as described above can be created.

The present invention relates to a recording device for additionally recording information on such an optical disc, and an optical information processing device for reproducing information from the optical disc.

The present invention will be explained below with reference to Examples.

FIG. 6 is a diagram illustrating the configuration of an embodiment of the recording apparatus of the present invention. The optical disk 66 having the above-mentioned guide groove (guide pit) rotates in the direction of the arrow in the figure about the rotation center shaft 71. A light beam (indicated by diagonal lines) emitted from the semiconductor laser 81 via the optical system 82 is reflected by the optical disk 66, returns to the optical path, and returns to the semiconductor laser 81. Then, the amount of light emitted from the semiconductor laser 81 is modulated by the light returning from the disk. Therefore, by detecting the light emitted from one end of the semiconductor laser 81 by the photodetector 80, the signal on the disk can be read out. This detection method is known as the so-called self-coupling effect of semiconductor lasers.

FIG. 7a shows a reproduced signal 93 from the detector 80. What appears below the reproduced signal 93 is
It is a change of the envelope of the signal by the guide groove of this invention. If the spot of the light beam is completely irradiated in the center of the groove, the repetition period of the envelope will be 2T. When the spot deviates from the groove toward either the inner or outer circumference of the disk, signals with different phases at a period T appear on the envelope. This is used for tracking.

A signal 93 from the detector 80 is input to a tracking signal detector 84, and a tracking signal is detected by a known tracking method disclosed in Japanese Patent Application Laid-Open No. 103515/1983. This tracking signal is input to the phase compensation circuit 85 to stabilize the control system.
This output drives a linear motor 83 to move an optical head (consisting of a semiconductor laser and an optical system) connected to the linear motor to perform tracking. In this way, the light spot tracks the guide groove.

In order to perform recording, the signal 93 from the photodetector 80 is first input to the digital signal detection circuit 86, where it is converted by conventional means and methods (for example, converting the analog signal into a digital signal using a comparator, Also, phase synchronization is performed to generate a signal synchronized with the detection signal clock.)
Signal 87 corresponding to the pit row forming the guide groove
(hereinafter referred to as a guide pulse signal) and a synchronous clock 89 are generated. The relationship between these two signals on the time axis is shown in FIGS. 7b and 7c, which corresponds to the geometric arrangement of FIG. 1 on the disk surface.

The guide pulse 87 and synchronization clock 89 are input to an additional recording clock generator 88 to generate a recording clock 95 for additional recording from the two signals.

The recording clock is modulated by a transformer 90 in accordance with a signal from a generator 91 of the information signal to be additionally recorded, and this modulated signal 94 is input to a semiconductor laser drive circuit 92 to adjust the laser oscillation power of the semiconductor laser. Modulate.

Here, since the recording clock 95 does not overlap the guide pulse 87 on the time axis, according to the above method, additional recording pits are formed between the pits forming the guide grooves.

As shown in FIGS. 7d and 7e, the simplest modulation method is to create the recording clock 95 by exclusive ORing the signals 87 and 89, and by ANDing this with the information signal. There are ways to obtain the modulated signal 94.

A device for reproducing information recorded in the above manner will be explained with reference to FIG.

In FIG. 8, the same numbers as in FIG. 6 have the same operations and effects. Playback signal 10
0 has a waveform similar to that shown in FIG. 7a, as shown in FIG. 9, except that it includes additional recording information. The tracking signal is detected in the same manner as in the embodiment of FIG.

FIG. 9 shows a reproduced signal from the optical disk shown in FIG. In this case, since the degree of modulation of the signal from the additional recording pit is smaller than the degree of modulation of the signal from the pit forming the guide groove, it is easier to extract additional information from the data signal compared to the above embodiment. It can be separated into That is, by selecting the level of the comparator from the analog reproduced signal, only the guide pulse can be detected, and using this, only the additional information signal can be detected from the data signal.

The reproduced signal 100 is sent to a digital signal converter 101
By using the usual method (using a comparator to convert an analog signal to a digital signal and converting it to a PLL
A pulse whose phase is synchronized with the synchronization signal included in the reproduced signal is formed. ) generates a data signal 106 (shown in FIG. 10a) and a synchronization clock 105 (shown in FIG. 10b) corresponding to the recorded pit. The two signals are input to the demodulator 102 to obtain an additionally recorded information signal 107.

The operation of demodulator 102 will be explained using FIG. 10. Since the data signal 106 includes a guide pulse, the guide pulse is created from the synchronized clock 105 (in this case, since the guide pulse is a pulse train of constant repetition, a characteristic signal indicating the beginning of the data signal is generated). (obtained by dividing the frequency of the synchronization clock as follows.) When the recording clock for additional recording is reproduced by the exclusive OR of the guide pulse and the synchronization clock 105, the signal shown in FIG. 10c is obtained. When this signal and the data signal 106 are ANDed, the additional recording information signal 107 (10th
(shown in Figure d) is obtained.

Yet another embodiment will be described using FIG. 11. A signal 93 from the photodetector 80 is input to a digital signal detection circuit 86', which generates a signal φ1 corresponding to the pit row forming the guide groove and a synchronous clock φ6. Here, the relationship between the two signals φ1 and φ6 on the time axis is shown in FIG. In this embodiment, the repetition period of φ1 is T, and that of φ6 is t, which is selected so as to satisfy the relationship T=6×t. A method of creating a pulse train from φ1 indicating the pit row of the guide groove to φ6 by PLL is well known.

Additional recording clock generator 8 for φ6 and φ1 signals
8', the recording clock signals φ4 and φ5 shown in FIG. 13 are created using a sequential circuit such as a known counter. The signal (data) of the information signal to be additionally recorded from the generator 91' is modulated by the modulation circuit 90' according to the recording clock, and this modulation signal 94' is inputted to the semiconductor laser drive circuit 92'. Modulates the laser oscillation power of a semiconductor laser.

The modulation method and modulation circuit 90' of this embodiment will be explained in detail. The preferred method for the modulation method of the present invention is encoding, which treats data in units of m bits and converts it into n recording bits, and converts this into NRZI.
(or NRZ). An example will be described in which one called 4/5MNRZI is used.

4/5 conversion is the case where m=4 and n=5. A conversion table for this is shown in FIG. The configuration of the modulation circuit 90' is shown in FIG. 14, and the timing chart is shown in FIG. 13. Data is first stored in memory 200. Data is read out in accordance with clock φ4 and transferred to 4-bit register 201 every cycle T. The combination of the AND circuit 203 and the OR circuit 204 in FIG. 14 performs the conversion shown in FIG. 12, and the result is latched into the 5-bit register 202. When this is read out according to clock φ5, a modulation signal 94' is formed.

An apparatus for reproducing information recorded in accordance with the above-described embodiment will be explained with reference to FIG. 15th
In the figure, a reproduced signal 100' is converted into a reproduced data signal 10 by a digital signal converter 101'.
A pulse signal 105' whose phase is synchronized with the synchronizing signal included in the reproduction signal 6' and the reproduced signal is generated.

The means for generating the aforementioned signals 106' and 105' from the signal 100' will be explained. Since 4/5 conversion is performed, there is always at least one pit in the area other than the pit forming the guide groove, that is, in the area where additional information is recorded. Therefore, since a signal component with a period t exists in the reproduced signal, phase synchronization can be performed by the PLL to synchronize with this period, and the signal 10
5' can be generated.

Further, as shown in FIG. 16, the pulse train φ1 corresponding to the pit forming the guide groove is the signal 1
05'. That is, in an apparatus for recording digital information such as the present invention, recorded information is divided into blocks each consisting of a specific number of bits, and a signal indicating the division of the blocks is always inserted. Therefore, if the relationship of the signal φ1 indicating this division is set to a predetermined rule, φ1 can be obtained by dividing the signal 105' into 1/6 using the signal indicating the division.

A reproduced data signal 106' is obtained by removing the signal corresponding to the pit forming the guide groove from the reproduced signal 100' using the aforementioned φ1. The means for demodulating this reproduced data signal 106' will be further explained with reference to FIG.

Signal 105' is input to demodulation clock generator 110 to generate demodulation clock signals φ4 and φ5. Then, the reproduced data signal 106' is converted into a signal φ4,
Demodulation is performed using the demodulation circuit 111 according to φ5 to obtain demodulated data.

The demodulation method will be explained using FIG. 17. The reproduced data signal 106' is taken into the 5-bit shift register 120 according to the signal φ5, and
A combination of the circuit 122 and the OR circuit 123 converts the 5-bit pattern into a 4-bit pattern, which is latched into the 4-bit shift register 121 and read out every cycle T in accordance with the signal φ4.

[Brief explanation of the drawing]

1 to 5 are diagrams showing the configuration of an optical disc on which information is additionally recorded according to the present invention, and FIG. 6 is a diagram showing the configuration of an embodiment of the additional recording device according to the present invention. FIG. 7 is a time chart of signals for explaining the operation of the device shown in FIG. FIG. 8 is a block diagram of an embodiment of the present invention, which is a device for reproducing signals from an additionally recorded disc. FIG. 9 is a diagram showing a reproduction signal from an additionally recorded disc. FIG. 10 is a time chart when a signal is reproduced from an additionally recorded disc. FIG. 11 is a diagram showing the configuration of another embodiment of the present invention. Figures 12 and 13 are
FIG. 2 is a diagram for explaining essential parts of the present invention. Figure 14 shows
FIG. 1 is a diagram showing the configuration of an embodiment of a main part of the present invention. 15th
The figure is a diagram showing the configuration of another embodiment of the present invention. 1st
FIG. 6 is a diagram for explaining the operation. FIG. 17 is a diagram showing the configuration of an embodiment of the main part of the present invention.

Claims (1)

[Scope of Claims] 1. A recording medium on which information signals are recorded in a form that can be optically read, wherein a row of pits is recorded at a predetermined interval, and the row of pits meander in the direction of movement of the recording medium. a recording medium in which the space between the pits is a recording section for an information signal; a means for illuminating the recording medium with a light spot to read out the pit row; and a clock having a period corresponding to the pit row from the read signal. means for creating a tracking signal from the read signal; and means for creating a modulation signal for forming information pits in a recording section between the pits from the information signal to be recorded and the clock. An optical information processing device comprising: controlling the irradiation position of the light spot using the tracking signal and modulating the intensity of the light spot using the modulation signal to form information pits in the recording section. . 2. The optical information processing device according to claim 1, wherein the period of the clock is an integral multiple of the period of the pit row. 3. A recording medium on which information signals are recorded in a form that can be read optically, in which rows of pits are recorded at predetermined intervals, and the rows of pits meander in the direction of movement of the recording medium, and between the pits. a recording medium which is a recording section for information signals; means for illuminating the recording medium with a light spot to read out the pit row; and means for creating a clock having a period corresponding to the pit row from the read signal; means for detecting a tracking signal from the read signal; and means for reproducing information pits recorded in the recording section between the pits based on the clock while controlling the irradiation position of the light spot using the tracking signal. An optical information processing device comprising: 4. The optical information processing device according to claim 3, wherein the period of the clock is an integral multiple of the period of the pit row.