JPH076429A - Optical disc and optical disc reproducing apparatus - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an optical disc that can be configured at a low cost and can be configured at a low cost, can improve the S / N of a reproduction signal, and can expect a highly accurate servo. [Structure] 2 is an optical disc, in which all servo signals and data are recorded in pits when it is a ROM medium, whereas all are servo-optically recorded when it is a RAM medium. 11 is an optical head, and the adder 1
A signal is obtained from 2 according to the amount of reflected light from the optical disc 2, and a signal is obtained from the subtracter 21 according to the rotation of the polarization plane of the reflected light from the optical disc 2. Optical disc 2
Switch 3 when is ROM media and RAM media
1 is connected to the a side and the b side, and servo error detection, clock signal reproduction, data detection, etc. are performed from the output signals of the adder 12 and the subtractor 21, respectively. The data detection circuit 19 is commonly used regardless of whether the optical disc 2 is a ROM medium or a RAM medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk in which digital data is magneto-optically recorded in all or part of a data area, and a magneto-optical disk in which digital data is magneto-optically recorded, and digital data is recorded in pits. The present invention relates to a reproducing device for an optical disc or the like.

[0002]

2. Description of the Related Art Conventionally, in a magneto-optical disk as a RAM medium, addresses and servo information are pre-formatted in the medium by pits in both the continuous groove servo system and the sample servo system, and digital data is stored in a data area. Magneto-optically recorded.

On the other hand, in an optical disc as a ROM medium, similarly, the address and servo information are pre-formatted in the medium with pits (phase pits), and the digital data is also pre-formatted with pits in the data area. .

FIG. 5 shows an example of a recording / reproducing apparatus compatible with both the magneto-optical disk as the RAM medium and the optical disk as the ROM medium described above.
In this example, the servo system of the optical disk is the sample servo system.

In the figure, 1 is a spindle motor, and the optical disk 2 is rotationally driven by the motor 1 at a constant angular velocity.

Recording data from a host computer (not shown) is stored in the controller 3 and the data buffer 4.
And is supplied to the encoder / decoder 5 via an encoder to perform an encoding process (addition of error correction code, modulation, etc.).
The operation of the encoder / decoder 5 is controlled by the controller 3. The controller 3 has a CPU 6, RO
M7 and RAM8 are connected.

Recording data (modulation data) output from the encoder / decoder 5 is supplied to a drive circuit 9 of a magnetic head 10 for generating an external magnetic field. Optical disc 2 is R
In the case of AM media, the magnetic head 10 generates a magnetic field according to the recording data, and the recording data is magneto-optically recorded in the data area of the disk 2 in cooperation with the laser beam from the optical head 11.

FIG. 6 shows an example of the structure of the optical head 11. Reference numeral 101 is a semiconductor laser, and the laser light from the semiconductor laser 101 is collimator lens 102, beam cross-section shaping lens 103, and deflection beam splitter 10.
4, the recording surface of the optical disc 2 is irradiated with light through the mirror 105 and the objective lens 106.

The amount of light reflected from the pits of the optical disc 2 changes depending on the presence or absence of pits, while the amount of light reflected from the magneto-optical recording section of the optical disc 2 has its polarization plane rotated in accordance with the recorded data. Becomes

The reflected light from the optical disk 2 is the objective lens 106, the mirror 105 and the polarization beam splitter 10.
The light beam is incident on the polarization beam splitter 107 via No. 4.
Then, the light transmitted through the polarization beam splitter 107 is incident on the photodetector 110 via the condenser lens 108 and the cylindrical lens 109.

The light reflected by the polarization beam splitter 107 has its plane of polarization rotated by 45 ° by the ½ wavelength plate 111, and then enters the polarization beam splitter 113 via a condenser lens 112. The light (p-polarized light) transmitted through the polarization beam splitter 113 enters the photodetector 114 and is reflected by the polarization beam splitter 113 (s).
The polarized light is incident on the photodetector 115.

Returning to FIG. 5, the output signals of the photodetectors 114 and 115 of the optical head 11 are supplied to the adder 12 and added. The addition signal (RF signal) output from the adder 12 becomes a signal corresponding to the recording data during the period when the reflected light is obtained from the pit portion of the optical disc 2.

The output signal of the adder 12 is supplied to the sector mark detection circuit 13. FIG. 7 shows a sector format in the sample servo system, which is configured by first arranging a header part and subsequently arranging a plurality of data parts. Servo bytes SB are provided at the beginning of the header part and each data part, and in the above-mentioned RAM media and ROM media, clock pits and wobble pits are pre-formatted in the servo bytes SB. Further, signals of a sector mark, a sector address and a track address are recorded in the header part, and these signals are also pre-formatted with pits.

In the sector mark detection circuit 13, the adder 1
The sector mark is detected from the output signal of 2 and the detected signal is supplied to the timing generator 14. Then, the timing generator 14 forms various timing signals used in each section based on the sector mark detection signal. The operation of the timing generator 14 is controlled by the CPU 6.

Further, the output signal of the adder 12 is supplied to the clock reproduction circuit 15, and the clock CK is reproduced based on the reproduction signal of the clock pit or wobble pit in the portion of the servo byte SB. This clock CK is used as a system clock in each unit.

Further, the output signal of the adder 12 is supplied to the tracking error detection circuit 16, and the tracking error signal is detected based on the reproduction signal of the wobble pit of the portion of the servo byte SB, and the tracking error signal is detected by the servo circuit 17. Is supplied to. In addition, the optical head 11
The output signal of each photodetector of the photodetector 110 (see FIG. 6) is supplied to the focus error detection circuit 18, the focus error signal is detected, and this focus error signal is supplied to the servo circuit 17.

The operation of the servo circuit 17 is controlled by the controller 3. With this servo circuit 17, the optical head 1
The tracking servo and the focus servo of 1 are performed, and the seek control is also performed based on the address signal obtained from the reproduction signal of the header section.

The output signal of the adder 12 is supplied to the data detection circuit 19. The data detection circuit 19 performs waveform equalization processing of the reproduced signal and the like to detect data. The data detected by the data detection circuit 19 is supplied to the fixed terminal on the a side of the changeover switch 20.

Further, the photodetector 114 of the optical head 11,
The output signal of 115 (see FIG. 6) is supplied to the subtractor 21 and is subtracted. The subtraction signal (MO signal) output from the subtractor 21 becomes a signal corresponding to the recording data during the period when the reflected light is obtained from the magneto-optical recording section of the optical disc 2. The output signal of the subtractor 21 is supplied to the data detection circuit 22. The data detection circuit 22 performs waveform equalization processing of the reproduced signal and the like to detect data. The data detected by the data detection circuit 22 is the changeover switch 2
0 is supplied to the fixed terminal on the b side.

The changeover switch 20 includes a timing generator 1
A switching control signal is supplied from 4. Optical disc 2 is RO
When it is M media, it remains connected to the a side. On the other hand, when the optical disk 2 is a RAM medium, it is connected to the side b during the reproduction of the magneto-optical recording portion such as the data portion, and the reproduction of the pit portion such as the servo byte SB and the address recording portion of the header portion is performed. The period is a
Connected to the side.

The data output from the changeover switch 20 is supplied to the encoder / decoder 5 and is subjected to decoding processing (error correction, demodulation, etc.). The encoder / decoder 5 outputs reproduction data reproduced from the data section and address signals reproduced from the header section, and the reproduction data and address signals are supplied to the controller 3.

[0022]

As described above, the RAM
The medium has a pre-pit portion in addition to the magneto-optical recording portion, and the yield of the medium is the product of the yield of the pre-pit portion and the yield of the magneto-optical recording portion, so that the yield decreases and the cost increases. there were. Also, R
Since the AM medium has a pre-pit portion, the medium is mechanically deformed, optical birefringence occurs, the S / N of the reproduced signal is deteriorated, and the servo signal such as the focus error signal is deteriorated. There was a problem that a high precision servo could not be expected.

In addition, the recording / reproducing apparatus described above is provided with the data detection circuit 22 which is used only when the optical disk 2 is a RAM medium, in addition to the data detection circuit 19. When the optical disk 2 is a RAM medium, it is necessary to switch the data detection circuits 19 and 22 at high speed, and it is difficult to control this high speed switching. As a result, there are problems such as an increase in cost.

Therefore, the present invention provides an optical disk which has a high yield and can be constructed at low cost, can improve the S / N ratio of the reproduction signal, and can expect a servo with high precision. The present invention also provides an optical disk reproducing apparatus that does not require a dedicated data detection circuit when the optical disk is a RAM medium and does not require high-speed switching processing of the data detection circuit that accompanies it, and that can be inexpensively constructed.

[0025]

An optical disk according to a first invention is an optical disk in which digital data is magneto-optically recorded in all or a part of a data area, and the data area in which the digital data is magneto-optically recorded. All of the signals recorded in the other areas related to are those which are magneto-optically recorded.

The optical disk reproducing apparatus according to the second invention is
First light detecting means for detecting the amount of reflected light from the optical disk, second light detecting means for detecting rotation of the polarization plane of the reflected light, and output signals of the first and second light detecting means. And signal processing means for processing the output signal of the signal switching means to obtain reproduced data.

[0027]

According to the first aspect of the invention, since all the signals recorded in the other area related to the data area where the digital data is magneto-optically recorded are magneto-optically recorded, the yield of the medium can be improved. The yield is improved, and the yield can be improved and the cost can be reduced as compared with the conventional one having a prepit portion.

Further, since the medium does not have a prepit portion, mechanical deformation or optical birefringence does not occur in the medium, and the prepit portion does not leak to the reproduced signal, thus improving the S / N of the reproduced signal. It becomes possible.
Furthermore, the media does not have a pre-pit part,
The accuracy of servo signals such as focus error signals is improved,
The acceleration (acceleration) of the servo becomes smaller,
High-precision servo is possible.

It should be noted that the same can be said with respect to a partial area of an optical disc in which a part of digital data is magneto-optically recorded.

In the second invention, the output signals of the first light detecting means for detecting the intensity of the reflected light from the optical disk and the second light detecting means for detecting the rotation of the polarization plane of the reflected light are signaled. Switching is performed by the switching means, and an output signal of the signal switching means is processed to obtain reproduced data, which can be constituted by one data detection circuit. Further, when the optical disk is a RAM medium as in the first aspect of the invention, the signal switching means does not require high speed switching processing. As a result, it is possible to configure at low cost.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, parts corresponding to those in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the figure, the output signal of the adder 12 is supplied to the fixed terminal on the side a of the changeover switch 31. Further, the output signal of the subtractor 21 is supplied to the fixed terminal on the b side of the changeover switch 31.

The changeover of the change-over switch 31 is controlled by the CPU 6, and is connected to the side a when the optical disk 2 is a ROM medium and to the side b when the optical disk 2 is a RAM medium. When the optical disk 2 has both a ROM media area and a RAM media area (hereinafter referred to as “mixed disk”), it is connected to the side a when the ROM media area is reproduced, and the RAM media area. Is connected to the side b during recording and reproduction.

Here, unlike the conventional optical disk 2 as a RAM medium in this example, addresses and servo information are pre-formatted on the medium by magneto-optical recording, and digital data is magneto-optically recorded on the data area. It The same applies to the area of the RAM medium when the optical disc 2 is a mixed disc.

On the other hand, in the optical disk 2 as the ROM medium in this example, the address and the servo information are pre-formatted on the medium by pits (phase pits) as in the conventional case, and the digital data is also pitted in the data area. Is pre-formatted with. Optical disc 2
In the case where is a mixed disk, the same applies to the area of the ROM medium.

In this example, the sample servo system is adopted as the servo system of the optical disk 2, and either the self-clock system or the non-self-clock system is possible as the data format. In the case of the self-clock system, the clock reproduction circuit (PLL circuit) 15 is locked in the servo byte area at the time of writing, the writing is performed by the clock CK output from this clock reproduction circuit 15, and at the time of reading, the self-clock method is performed by the data clock Reading is performed. On the other hand, in the case of the non-self clock system, the clock recovery circuit 15 is locked in the servo byte area during writing and reading,
Clock CK output from the clock reproduction circuit 15
Writing and reading are performed with.

In the case where the optical disk 2 is a RAM medium (including the area of the RAM medium of the mixed disk) and a ROM medium (including the area of the ROM medium of the mixed disk), the tracking error signal is obtained by the same process in both. The tracking error detection signal is recorded in the servo bite portion as shown in FIGS. 2 to 4, for example.

The example of FIG. 2 will be described. The same figure A is RA
This is an example of recording on an M medium, and a logic "1" is magneto-optically recorded in a conventionally known wobble pit shape. That is, the logical "1" is intermittently recorded alternately on one side and the other side centering on the normal tracking control position. A logical "0" is recorded in the portion other than the logical "1" recorded in the wobble pit shape.
Are placed in the state of being magneto-optically recorded. In this case, the tracking error detection circuit 16 detects the difference between the output signals of the subtractor 21 at the times t1 and t2 as a tracking error signal. The lines indicated by n and n + 1 are tracking control positions. The logical "0" may be recorded in the wobble pit shape. In that case, a logical "1" is recorded in the other part.

FIG. 9B shows an example of recording on the ROM medium.
Wobble pits are formed corresponding to the logical "1" portion recorded in the wobble pits of the RAM medium.
In this case, the tracking error detection circuit 16 detects the difference between the output signals of the adder 12 at the times t1 and t2 as a tracking error signal. n and n + 1
The line indicated by is the tracking control position, and the tracking control is performed at the same position as in the case of the RAM medium.

Next, the example of FIG. 3 will be described. Same figure A
Is a recording example of a RAM medium, in which a logical "1" is continuously magneto-optically recorded on one side and a logical "0" is continuously magneto-optically recorded on the other side around the normal tracking control position. In this case, the tracking error detection circuit 16
As described above, the output signal of the subtractor 21 during the period in which the tracking error detection signal is recorded is directly detected as the tracking error signal. The lines indicated by n and n + 1 are tracking control positions. The recording positions of the logical "1" and "0" may be reversed. In that case, the sign relationship of the tracking error signal is reversed.

FIG. 9B shows an example of recording on the ROM medium.
Pits are continuously formed corresponding to the logical "1" portion recorded in the RAM medium. In this case, when the output signal of the adder 12 is directly detected by the tracking error detection circuit 16 as the tracking error detection signal,
Lines indicated by n and n + 1 are tracking control positions, and an offset occurs in the case of a RAM medium. Therefore, in the tracking error detection circuit 16, a signal obtained by adding an offset value to the output signal of the adder 12 is detected as a tracking error detection signal, and RA
Processing is performed so that tracking control is performed at the same position as in the case of M media.

Next, the example of FIG. 4 will be described. Same figure A
Is an example of recording on a RAM medium, in which a logical "1" is continuously magneto-optically recorded at the normal tracking control position, and a logical "0" is magneto-optically recorded at other portions. In this case, as described above, the optical head 11 is wobbled during the period in which the tracking error detection signal is recorded, and the tracking error detection circuit 16 detects the tracking error signal for controlling the subtraction signal to the maximum value. It The recording positions of the logical "1" and "0" may be reversed. In that case, the tracking error detection circuit 16 detects the tracking error signal for controlling the subtraction signal to the minimum value.

FIG. B shows an example of recording on a ROM medium.
Pits are continuously formed corresponding to the logical "1" portion recorded in the RAM medium. In this case, in the tracking error detection circuit 16, the optical head 11 is wobbled during the period in which the tracking error detection signal is recorded, and in the tracking error detection circuit 16, the tracking error signal for controlling the addition signal to the maximum value is controlled. Is detected.

In the above configuration, the optical disk 2 is RA
In the case of the M medium (mixed disk including the area of the RAM medium), the changeover switch 31 is connected to the b side, and tracking is performed from the subtraction signal obtained corresponding to the tracking error detection signal recorded in the servo byte portion. As described above, the error detection circuit 16 detects the tracking error signal to perform tracking servo, and recording / reproduction is performed in this state. At the time of reproduction, the output signal of the subtracter 21 (which becomes a signal corresponding to the magneto-optically recorded data) is supplied to the data detection circuit 19 to perform the data detection processing, and as in the example of FIG.
Reproduced data and the like are output from the decoder 5 and supplied to the controller 3.

When the optical disk 2 is a ROM medium (mixed disk including the area of the ROM medium), the changeover switch 31 is connected to the side a and corresponds to the tracking error detection signal recorded in the servo byte portion. Tracking error detection circuit 1 from the added signal obtained by
As described above in 6, the tracking error is detected, the tracking servo is performed, and the reproduction is performed in that state. Then, the output signal of the adder 12 (which becomes a signal corresponding to the pit data) is supplied to the data detection circuit 19 to perform the data detection processing, and the reproduction data and the like are output from the encoder / decoder 5 as in the example of FIG. It is output and supplied to the controller 3.

As described above, in this embodiment, the RAM medium as an optical disk has addresses and servo information pre-formatted on the medium by magneto-optical recording, and digital data is magneto-optically recorded on the data area. Since the signal of (1) is magneto-optically recorded, the yield of the medium is determined by the yield of the magneto-optical recording portion, and the yield is improved and the cost can be reduced as compared with the conventional one having a pre-pit portion.

Further, since this RAM medium does not have a prepit portion, mechanical deformation or optical birefringence does not occur in the medium, the prepit portion does not leak to the reproduced signal, and the S / N of the reproduced signal is reduced. Can be improved. Since the medium does not have a prepit portion, the accuracy of servo signals such as focus error signals is improved, and highly accurate servo can be expected.

According to the recording of the tracking error detection signal at the regular tracking control position as shown in FIG. 4, the tracking error detection signal is recorded at both sides of the regular tracking control position as shown in FIGS. Even if the CLV method (constant linear velocity method) is used, it is possible to reduce the influence of the tracking error detection signal on the signal of the data portion of the adjacent track, and to easily realize the CLV method, as compared with the case where the recording is performed by shifting. it can.

In this example, the optical disk 2 is RA
The data detection circuit 19 is commonly used for both the M medium and the ROM medium, and the number of data detection circuits can be reduced by half compared to the conventional example of FIG. Further, when the RAM medium of this example in which all signals are magneto-optically recorded is used, the high-speed changeover process of the changeover switch 31 becomes unnecessary. Therefore, the cost can be reduced as compared with the conventional example.

Although the sample servo system is adopted as the servo system of the optical disk 2 in the above-mentioned embodiment, the present invention can be applied to the system adopting the continuous groove servo system as well.

[0051]

According to the first aspect of the present invention, since all signals recorded in other areas related to the data area where the digital data is magneto-optically recorded are magneto-optically recorded, the yield of the medium is optical. The yield is determined by the yield of the magnetic recording portion, and the yield is improved and the cost can be reduced as compared with the conventional one having a prepit portion.

Further, since the medium does not have a prepit portion, mechanical deformation or optical birefringence does not occur in the medium, the prepit portion does not leak to the reproduced signal, and the S / N of the reproduced signal is improved. be able to. Further, since the medium does not have a pre-pit portion, the accuracy of servo signals such as focus error signals is improved, acceleration in servo is small, and high-precision servo is possible.

In the case of an optical disc having a part of digital data recorded magneto-optically, the same can be said with respect to the partial area.

According to the second invention, the output signals of the first light detecting means for detecting the intensity of the reflected light from the optical disk and the second light detecting means for detecting the rotation of the polarization plane of the reflected light are output. The signal is switched by the signal switching means and the output signal of the signal switching means is processed to obtain reproduced data, which can be constituted by one data detection circuit. Further, when the optical disk is a RAM medium as in the first aspect of the invention, the signal switching means does not require high speed switching processing. As a result, it can be constructed at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a tracking error detection signal in the embodiment.

FIG. 3 is a diagram showing another example of a tracking error detection signal in the embodiment.

FIG. 4 is a diagram showing another example of a tracking error detection signal in the embodiment.

FIG. 5 is a block diagram showing a conventional recording / reproducing apparatus for a RAM medium and a ROM medium.

FIG. 6 is a diagram showing a configuration example of an optical head.

[Figure 7] Sector format (sample servo method)
FIG.

[Explanation of symbols]

 2 optical disk 3 controller 5 encoder / decoder 6 CPU 10 magnetic head 11 optical head 12 adder 17 servo circuit 19 data detection circuit 31 changeover switch

Claims (5)

[Claims] 1. An optical disc in which digital data is magneto-optically recorded in all or part of the data area, and all signals recorded in other areas related to the data area in which the digital data is magneto-optically recorded. An optical disc on which is recorded magneto-optically. 2. A tracking error detection signal,
2. The magneto-optical recording of one logical data is alternately intermittently recorded on one side and the other side of the regular track.
The described optical disc. 3. A tracking error detection signal,
2. The optical disk according to claim 1, wherein one and another logical data are continuously recorded magneto-optically in predetermined areas on one side and the other side of the regular track which face each other. 4. A tracking error detection signal,
2. The optical disc according to claim 1, wherein one logical data is continuously magneto-optically recorded in a predetermined range on the regular track. 5. A first light detecting means for detecting a light quantity of reflected light from the optical disk, a second light detecting means for detecting rotation of a polarization plane of the reflected light, and the first and second lights. An optical disk reproducing apparatus comprising: signal switching means for switching the output signal of the detecting means; and signal processing means for processing the output signal of the signal switching means to obtain a reproduction signal.