JP3440072B2 - Information recording device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writable optical disk reader.

[0002]

2. Description of the Related Art In a writable type optical disc, a synchronization signal for address search, address information and the like (hereinafter, such information is referred to as "pre-information") are pre-recorded on the disc in a pre-format stage. As a method of pre-formatting this pre-information, the track (groove or land) on which the information is recorded is wobbled or recorded as pre-pits on the track.

[0003]

However, in the case of pre-formatting by wobbling, since the track itself is swung left and right by the wobbling signal,
There is a problem that the modulation factor of the wobbling signal is limited and the C / N is bad. Further, in consideration of the interference with the adjacent track due to the wobbling, the track pitch cannot be reduced so much, and the recording capacity is limited.

On the other hand, in the case of pre-formatting with pre-pits, there is a problem that the information cannot be recorded as much as the pre-pits are recorded and the utilization efficiency of the recording surface of the disc is poor.

The present invention is an information recording apparatus including a reading apparatus for generating a prepit signal from a writable optical disk, which is made to solve the above problems, and records recording information on an information recording track. An object of the present invention is to provide an information recording device including a reading device capable of removing the influence caused by the above and obtaining a prepit signal with a good C / N.

[0006] In order to solve the above-mentioned problems, the present invention is defined in claim 1.
The described invention is directed to an information recording track and the information recording track.
Track for guiding the light beam to the rack,
For the first recording pattern or the first recording pattern
Any of the second recording patterns having a predetermined phase difference
At a constant linear velocity.
Pre-pit information as well as having re-pit information
Is the pre-recording recorded in the first recording pattern.
Information that is adjacent to each other across the information recording track.
The same as the pre-pit information recorded on the id track.
When writing, the writing recorded with the second recording pattern is performed.
Information recording device for recording record information on a recordable optical disc
Generating a modulated signal based on the recorded information.
Modulation means and an optical beam modulated based on the modulation signal.
Irradiating means for irradiating the information recording track with
The reflected light of the light beam emitted by the irradiation means
By a dividing line that is optically approximately parallel to the radial direction of the disk
Light receiving means for receiving light by at least divided light receiving portions
And generate a differential signal of the output of the divided light receiving unit.
Based on the differential signal generating means and the modulated signal, the information
The noise component due to the information recorded on the recording track
Corresponding groove that generates a pit cancel signal
From the bpit cancellation signal generating means and the difference signal
The groove pit cancel signal is subtracted, and the pre-
The pre-pit signal corresponding to the pit information is output as
And a repit signal output means .

In order to solve the above-mentioned problems, a second aspect of the present invention is provided.
The described invention is the information recording apparatus according to claim 1.
The groove pit cancel signal generating means is
The modulated signal is delayed for a predetermined time to generate a delayed signal
The groove pit key is generated by the delay signal and the modulation signal.
It is characterized by generating a cancel signal.

[0008]

According to the first aspect of the invention, the information recording tray
Rack, guide track, first recording pattern or
Is one of the second recording patterns, and
And having pre-pit information recorded on the track for recording
The pre-pit information is recorded in the first recording pattern.
The relevant pre-pit information is inserted across the information recording track.
Pre-pit information recorded on adjacent guide tracks and
When overlapping, the writing recorded by the second recording pattern
When recording record information on a pluggable optical disc, first
The modulation means generates a modulation signal based on the recorded information. Next
In addition, the irradiation means is an optical beam modulated based on the modulation signal.
The information recording track is irradiated with a beam. And receive light
The means emits the reflected light of the light beam emitted by the irradiation means.
By a dividing line that is optically approximately parallel to the radial direction of the optical disc,
Light is received by at least the divided light receiving portions. Next
In addition, the difference signal generating means is
Generate a minute signal. Meanwhile, the groove pit cancellation signal
The signal generation means, based on the modulation signal, the information recording track
Groove corresponding to the noise component due to the information recorded on the
Generates a pit cancel signal. And the pre-pit
The signal output means outputs the groove pit cancel from the differential signal.
Pre-pit corresponding to the pre-pit information
Output as a signal.

According to the invention described in claim 2, claim 1
In addition to the function of the invention described in 1.
The delay signal generation means delays the modulated signal by a predetermined time.
Signal is generated and the groove is generated by the delayed signal and the modulated signal.
Generates a pit cancel signal.

[0010]

EXAMPLES Examples of the present invention will be described below. FIG. 1 shows an optical disk according to the present invention (hereinafter, abbreviated as disk).
A schematic enlarged perspective view of the groove and land portion of one embodiment of
FIG. 2 is an arrangement state diagram of prepits recorded on the land.

In FIG. 1, reference numeral 1 is a disk made of a transparent resin such as polycarbonate.
A groove 2 as an information recording track and a land 3 as a guide track are spirally formed on the surface of the disk from the center position of the disk toward the outer peripheral position of the disk. In the case of the present invention, of the grooves 2 and the lands 3, pre-pits 4 for giving pre-pit information to the lands 3 forming the guide track are recorded by pre-formatting.

FIG. 1 is a schematic view for facilitating understanding of the invention. A metal reflection film 5 is formed on the lower surface side of the groove 2 and the land 3, and a protective film (illustrated in the figure) is formed on the lower side thereof. (Abbreviated) is applied to complete a single veneer disk. Therefore, in the case of FIG. 1, the recording / reproducing laser beam is emitted toward the groove 2 and the land 3 from the upper side of the drawing.

Further, in the case of the present invention, the pre-pit 4
Are recorded on every other land 3, as shown in FIG. The reason for recording every other land in this way is as follows. That is, when the optical pickup is tracking on the groove 2 during recording or reproduction, if pre-pits are formed on all lands, two pre-pit information of the lands 3 located on the left and right sides of the groove 2 at the same time. This is because the read information interferes with the pre-information and the pre-information cannot be accurately reproduced.

As another method for eliminating the interference between the left and right pre-pit information, a method as shown in FIG. 2B can be adopted. That is, as a recording pattern for recording the pre-pit information on the land portion, an EVEN (even number) pattern and an ODD (odd number) pattern as shown in the figure are used.
This is a method in which two patterns are prepared and prepit information is recorded using these two patterns.

The EVEN pattern and the ODD pattern are provided with sync Sy and ID information necessary for servo.
The positions of the sync Sy and the ID to be recorded in the EN pattern and the ODD pattern are shifted by 180 degrees. And
Of these two patterns, the EVEN pattern is usually used to record the pre-pit information, and the positions of the sync Sy and the ID of the recording patterns of the adjacent lands are likely to overlap with each other in the course of recording the lands in a spiral manner. When it becomes, switch to the ODD pattern and continue recording.
When the positions of the sync Sy and ID of the D pattern are likely to overlap, the pattern is returned to the EVEN pattern and recording is continued.

To manufacture a disk having the above structure,
A method as shown in FIG. 3 may be adopted. In the case of a conventional disc in which pre-pits are recorded in the groove portion, the groove portion is cut when the glass master is cut. Therefore, when the conventional cutting method is adopted, it is inevitable to cut the groove portion and then cut the pre-pit on the land portion again, which requires a lot of man-hours and makes it difficult to perform the accurate cutting.

Therefore, in the present invention, in laser cutting, contrary to the conventional case, the master stamper is produced by exposing and developing the resist surface on the glass substrate based on the prepit information recorded in the land portion. However, replication is performed using either a submaster obtained by subjecting this master stamper to electroforming treatment once, or a stamper obtained by subjecting this submaster to electroforming treatment an even number of times. Is. If such a method is adopted, the cutting process of the master is required only once, the prepits on the land are not displaced, and a high-precision disc can be manufactured.

FIG. 4 shows a cutting machine used for the laser cutting. In the figure, 10 is a high-power laser generator, which outputs a laser beam generated by the laser generator 10 to an encoder 1 in an optical modulator 11.
After the light is modulated by the land cutting information sent from 2, the light is condensed by the objective lens 13, and the glass substrate 1
The spots can be formed on the resist 15 of No. 4 in FIG.

The glass substrate 14 is set on a spindle motor 16, and the spindle motor 16 is rotated by a rotation detector 17 and a rotation servo circuit 18 at a constant linear velocity (CL).
V) is rotated. Furthermore, the spindle motor 16
The feed unit 19 allows the glass substrate 14 to be fed in the radial direction, and the position detector 20 and the feed servo circuit 21 control the feed of the glass substrate 14 in the radial direction at a predetermined feed rate to thereby register the glass substrate 14. The land portion is spirally cut from the center of the disc toward the outer periphery of the disc.

FIG. 5 shows a first embodiment of a reading device according to the present invention for reading information from a disc manufactured as described above. In the figure, reference numeral 31 denotes an objective lens. A reproducing laser beam is guided to the objective lens 31 by a prism 32, and the laser beam becomes a beam spot and is irradiated onto the recording surface of the disc 1.
The reflected light of the laser beam reflected by the recording surface of the disk 1 reaches the prism 32 through the same path, passes through the prism 32 as it is, and is irradiated onto the light receiver 33.

In the case of this embodiment, the light receiver 33 is a four-division type light receiver, and as will be described later, the light reception output of each of the four light reception elements A to D (for the sake of clarity, In the following description, the light reception output of each element is also shown by A to D), and the RF signal, the tracking error signal, and the pre-pit signal of the land portion are read. Note that 34 to 37 are amplifiers connected to the respective light receiving elements A to D, and 38 to 43 and 47 are adder / subtractors.

The positional relationship between the optical receiver 34 for receiving the reflected light of the laser beam from the disk 1 and the groove 2 and the land 3 on the disk 1 is as shown by an enlarged view P in the figure. There is. Therefore, in order to read the recorded information on the groove 2, all outputs A to D of the four light receiving elements may be added and output. In the example shown,
Output of adder 40 (A + D) and output of adder 41 (B +
By adding C) by the adder 43, the RF signal (A + B + C + D) is output from the terminal 46.

The tracking error signal can be obtained by the difference (A + D)-(B + C) between the left and right light receiving elements along the tracking direction of the groove 3. In this case, not the 0th-order light but the difference of the 1st-order light is obtained.
In the illustrated example, the output (A + D) of the adder 40 and the adder 4
By subtracting the output (B + C) of 1 by the subtractor 42, the tracking error signal (A + D) − from the terminal 45 is obtained.
It is output as (B + C).

To read the pre-pit information recorded on the land 3, the difference (A + B)-(C + D) between the front and rear light receiving elements along the radial direction of the disc can be obtained. In this case as well, the difference is not the 0th order light but the 1st order light. In the case of the illustrated example, the output (A
+ B) and the output (C + D) of the adder 39 are subtracted by the subtractor 47, so that the prepit signal (A +
B)-(C + D) is output.

As can be seen from the positional relationship in the enlarged view P,
Since the pre-pits 4 recorded on the lands 3 are recorded on every other land 3, the information of the pre-pits 4 can be read. If the pre-pits 4 are recorded on all the lands, different pre-pit information on the right and left lands of the groove 3 may be read at the same time, and there is a possibility that they cannot be used. In the present invention, in order to avoid such a situation, as described above, the pre-pits 4 are recorded every other land 3.

As a result of recording the pre-pits 4 on every other land 3, as is apparent from the layout diagram of FIG. 2, the land 3 on which the pre-pits 4 are recorded is recorded at the time when the track makes one round. Changes from the left side (right side) of the groove 2 to the right side (left side), but this change in position changes the prepit signal (A +) output from the terminal 44.
It can be easily detected by reversing the polarity of B)-(C + D).

FIG. 6 shows an example of actual reading of each signal by the reading device. As is clear from this measurement example, R
It can be seen that all of the F signal, the tracking error signal, and the pre-pit signal are read out sufficiently and reliably. Almost no influence of the RF signal on the pre-pit signal is seen, but this is because the depth of the track groove is set as shown in FIG.

FIG. 8 shows a second embodiment of the reading device according to the present invention. The second embodiment is a three-beam type reading apparatus in which dedicated light receivers 54, 55, 56 are prepared for the respective beam spots 50, 51, 52. Reference numerals 57 to 72 are adder / subtractors, and 78 is a coefficient multiplier.

In the case of this embodiment, the RF signal is added to the adder 6
8 (F + H) and the output of the adder 69 (E + G) are added by the adder 71, so that from the terminal 75 (E + F)
+ G + H) is output.

The focus error signal is detected by the astigmatism method using a cylindrical lens (not shown), and the output of the adder 68 (F + H) and the output of the adder 69 (E + G) are subtracted. By subtracting at 72, it is output as (F + H)-(E + G) from the terminal 76.

The pre-pit signal is obtained by subtracting the output (A + B) of the adder 57 and the output (C + D) of the adder 58 from the subtractor 6.
By subtracting by 4, the value from the terminal 73 becomes (A + B)-
It is output as (C + D).

The tracking error signal is obtained as follows. First, the output of the adder 61 (F + G)
The output (F + G)-(E + H) obtained by subtracting the output (E + H) of the adder 62 with the subtractor 66 is input to the + terminal of the subtractor 70. On the other hand, the output (B + C) of the adder 59 and the adder 6
0 output (A + D) subtracted by subtractor 65 (B +
C)-(A + D) is input to one terminal of the adder 67, the output (I + J) of the adder 63 is input to the other terminal of the adder 67, and the output of this adder 67 {(B +
C)-(A + D)} + {(I + J)} is a constant K for correction
K [{(B + C)-(A +) multiplied by (K = 0 to 1)
D)} + {(I + J)}] is input to the minus terminal of the subtractor 70.

As a result, the subtracter 70 outputs {(F +
G)-(E + H)}-(A + D)}-K [{(B + C)
-(A + D)} + {(I + J)}] is output as a tracking error signal. Therefore, the correction constant K
By properly adjusting the above, it is possible to reduce the noise signal due to the pre-pit 4 of the land 3 which is mixed in the original tracking error signal (F + G)-(E + H).

FIG. 9 shows a third embodiment of the reading device according to the present invention. In this embodiment, even in a disc in which the recording operation is performed on the disc 1 and the information is written on the groove 2, the influence of the recorded information is reduced as much as possible and the C / N ratio is reduced.
It is designed to obtain a good pre-pit signal.

In the case of this embodiment, a four-divided photodetector is used as the photodetector 80. In this embodiment, the 4-division type photodetector is used to obtain the RF signal and the tracking signal in addition to the prepit signal. However, when reading only the prepit signal, the 2-division photodetector is sufficient.

In the case of this embodiment, the pre-pit signal is obtained as follows. First, using the outputs A to D of the photodetector 80, the original prepit signal (A + B)-
Calculate (C + D). This pre-pit signal (A + B)-
The noise component due to the pit information recorded on the groove 2 is included in (C + D).

Therefore, a groove pit cancel signal for canceling this noise component is output from the output A of the photodetector 80.
A waveform shaping circuit 82 is created using D, and a subtractor 83 subtracts this groove pit cancellation signal from the prepit signal (A + B)-(C + D) to cancel the noise component.

A method of generating the groove pit cancel signal in the waveform shaping circuit 82 will be described with reference to FIG. Now, when no pre-pits are recorded on the land and the beam spot tracks on the groove of the disc in which pit information is recorded only on the groove, the added waveforms (A + B) and (C + D) respectively Figure 1
The waveform becomes 0 (A), (B).

On the other hand, the push-pull signal (A + B)-(C + D), which is a pre-pit signal, has a waveform as shown in FIG. 10 (F), and an output is generated even though the pre-pit is not recorded on the land. I will end up. This is a noise component due to the pit information recorded on the groove. Therefore, if this noise component is canceled, the influence of the pit information recorded on the groove on the pre-pit signal can be canceled.

Therefore, in the embodiment shown in FIG.
An output signal (A + B + C + D) as shown in FIG. 10C is made from the signals of (A) and (B), and this waveform is differentiated to obtain the output signal of FIG.
The differential signal of (D) is obtained. Then, a groove pit cancel signal as shown in FIG. 10E is created based on this differential signal.

The groove pit cancel signal of FIG. 10 (E) and the push-pull signal (A + B)-of FIG. 10 (F).
It can be seen that (C + D) has the same waveform. Therefore, in the subtractor 83 of FIG. 9, the push-pull signal (A + B)-(C + D), which is the pre-pit signal, is used to output the signal shown in FIG.
If you pull the groove pit cancellation signal of
It is possible to remove the influence of pit information recorded on the groove, such as 0 (G), and obtain a pre-pit signal with good C / N.

FIG. 11 shows a fourth embodiment of the reading device according to the present invention. This embodiment shows an example of a reading device capable of reading the pre-pit information of the land portion while recording the information on the disc 1. In this example,
Although a four-divided photodetector is used as the photodetector 90, the two-divided photodetector is sufficient for reading out only the pre-pit signal as in the case of the third embodiment.

In the figure, 90 is a light receiver, 91 is a subtractor, 92 is a laser beam modulator, 93 is a laser beam generator, 94 is a prism, 95 is an objective lens, and 96 is a waveform shaping circuit. The disk 1 is irradiated with the laser beam output from the laser beam generator 93 through the prism 94 and the objective lens 94.

Generally, the laser beam is turned on and off when recording information on the disc by a power control method as shown in FIG. That is, the laser power is controlled not to be 0 at the non-recording position but to be reduced to the reading power. Therefore, it is possible to read the pre-pit information of the land portion even during the non-recording period when no information is written in the groove.

In the case of this embodiment, the pre-pit signal is obtained as follows. First, the original pre-pit signal (A + B)-(C + D) is obtained from the outputs A to D of the light receiver 90. The pre-pit signal (A + B)-(C + D) contains a noise component due to the pit information recorded on the groove 2.

Therefore, a groove pit cancel signal for canceling out this noise component is created from the drive modulation signal waveform given to the laser beam generator 93 from the modulator 92 in the waveform generation circuit 96, and this groove is produced in the subtractor 91. The pit cancel signal is subtracted from the pre-pit signal (A + B)-(C + D) to cancel the noise component.

A method of generating the groove pit cancel signal in the waveform shaping circuit 96 will be described with reference to FIG. Now, when pit information is recorded on the groove by the recording light as shown in FIG. 13A in a state where no pre-pit is recorded on the land, the photodetector 90
The addition waveforms (A + B) and (C + D) of FIG.
The waveforms are as shown in (B) and (C). This FIG. 13 (B),
The waveform of (C) shows that a pit was recorded on the groove at a position where the addition output dropped stepwise, and the light amount of the reflected light decreased from the position due to the recording pit.

On the other hand, the push-pull signal (A + B)-(C + D), which is the pre-pit signal, has a waveform as shown in FIG. 13 (F), and an output is generated despite the assumption that the pre-pit is not recorded on the land. I will end up. This is a noise component due to the pit information recorded on the groove. Therefore, if this noise component is canceled, it is possible to cancel the influence of the pit information recorded on the groove on the pre-pit signal.

Therefore, in the illustrated embodiment, first, referring to FIG.
A delay waveform shown in FIG. 13D in which the recording light shown in FIG. 13A is delayed by time t is created, and the rear side of this delay waveform is truncated by time t to create the groove pit cancel signal in FIG. 13E.

The groove pit cancel signal of FIG. 13 (E) and the push-pull signal (A + B)-of FIG. 13 (F).
It can be seen that (C + D) has the same waveform. Therefore, in the subtractor 91 of FIG. 11, the push-pull signal (A + B)-(C + D), which is the pre-pit signal, is used for the above-mentioned FIG.
By subtracting the groove pit cancel signal of 3 (E), the influence of the pit information recorded on the groove can be removed, and a prepit signal with good C / N can be obtained.

In each of the above-mentioned embodiments, the pre-pit information is obtained by the push-pull signal of the light receiving portions located in the front and rear along the tracking direction, but the light receiving portions located on both the left and right sides in the tracking direction are obtained. The pre-pit information can be obtained also by the push-pull signal. In this case, the push-pull signals located on both the left and right sides are obtained by superimposing the signals due to the tracking error and the prepit, but since the tracking error signal and the prepit signal have significantly different frequency bands, by using a filter, It can be easily distinguished.

Further, the prepit information can be discriminated as a left prepit or a right prepit with respect to the groove depending on the polarity of the obtained signal.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made in accordance with the gist of the present invention.

[0054]

According to the information recording instrumentation <br/> location according to claim 1, wherein according to the present invention, the influence can be eliminated caused by recording the record information in the information recording track, good C / N prepit You can get a signal. Therefore,
The information can be recorded while acquiring the information.

[0055] According to the information recording apparatus according to claim 2, wherein according to the present invention, it is possible to simplify the configuration for generating a groove pit canceling signal.

[Brief description of drawings]

FIG. 1 is a schematic enlarged perspective view of a groove and a land portion of an embodiment of an optical disc according to the present invention.

FIG. 2 is a layout state diagram of pre-pits recorded on a land.

FIG. 3 is an explanatory diagram of an optical disc manufacturing method of the present invention.

FIG. 4 is a diagram showing a structural example of a cutting machine for a laser beam.

FIG. 5 is a block diagram of a first embodiment of a reading device according to the present invention.

FIG. 6 is a diagram showing an example of actual reading of each signal by the reading device.

FIG. 7 is a diagram showing depths of track grooves and output characteristics of push-pull signals and RF signals.

FIG. 8 is a block diagram showing a second embodiment of the reading device according to the invention.

FIG. 9 is a block diagram of a third embodiment of the reading device according to the present invention.

FIG. 10 is an explanatory diagram of a method of generating a groove pit cancel signal in the third embodiment.

FIG. 11 is a block diagram of a fourth embodiment of the reading device according to the present invention.

FIG. 12 is an explanatory diagram of a laser beam power control state during information recording.

FIG. 13 is an explanatory diagram of a method of generating a groove pit cancel signal in the fourth embodiment.

[Explanation of symbols]

1 disk 2 groove (information recording track) 3 land (guide track) 4 prepit (prepit information) 90 light receiver (light receiving means) 91 subtractor (prepit signal output means) 92 modulator 93 laser beam generator 94 prism 95 objective Lens 96 Waveform shaping circuit (groove pit cancellation signal generation means)

Continuation of front page (56) Reference JP-A-1-256026 (JP, A) JP-A-6-333240 (JP, A) JP-A-3-86935 (JP, A) JP-A-1-260635 (JP , A) JP-A-5-128535 (JP, A) JP-A-6-325382 (JP, A) JP-A-7-73475 (JP, A) JP-A-6-243468 (JP, A) JP-A-6-243468 (JP, A) 3-214428 (JP, A) JP 64-64125 (JP, A) JP 63-269356 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 7/00 -7/0013 G11B 7/12-7/22 G11B 7/24 G11B 20/10-20/12

Claims (2)

(57) [Claims] 1. An information recording track, and a guide track for guiding a light beam to the information recording track,
For the first recording pattern or the first recording pattern
Any of the second recording patterns having a predetermined phase difference
At a constant linear velocity.
Pre-pit information as well as having re-pit information
Is the pre-recording recorded in the first recording pattern.
Information that is adjacent to each other across the information recording track.
The same as the pre-pit information recorded on the id track.
When writing, the writing recorded with the second recording pattern is performed.
Information recording device for recording record information on a recordable optical disc
And a modulation means for generating a modulation signal based on the recorded information, and a light beam modulated based on the modulation signal as the information.
Irradiation means for irradiating the recording track, and reflected light of the light beam emitted by the irradiation means
By a dividing line that is optically approximately parallel to the radial direction of the optical disc,
Receiving hand that receives light by at least the divided light receiving unit
Stage and a difference for generating a difference signal of the output of the divided light receiving section
Recording on the information recording track based on the signal generation means and the modulation signal
Groove pit corresponding to the noise component due to the information
Groove pit cancellation signal that generates a cancellation signal
Signal generation means and the groove pit cancellation signal from the difference signal.
Pre-pit signal corresponding to the pre-pit information after subtraction
An information recording device comprising: a pre-pit signal output means for outputting as . 2. The groove pit cancel signal generation
The means generates a delayed signal obtained by delaying the modulated signal for a predetermined time.
The delay signal and the modulated signal,
A contract characterized by generating a bump cancel signal
The information recording device according to claim 1.