JPH07129960A - Optical disk recorder - Google Patents

Abstract

PURPOSE:To reduce the deviation amount of a formed pit length from the normal value while preventing the lowering of the definition of a recording signal when recording is performed on a phthalocyanine base disk by changing an irradiation time with a recording laser beam corresponding to a pit length to be recorded. CONSTITUTION:In an input device 28, a recording speed magnification is set by the operation, etc., of an operator. A disk servo circuit 16 controls the rotation at a constant linear velocity and at the recording speed magnification set in a disk motor according to a command from a system controller 19. By a data signal correction circuit 26 as a laser beam irradiation time control means, the irradiation time of the recording laser beam 11 is controlled according to the recording speed magnification and the pit length to be formed. Then, in an optical disk device with a CD-NO standard disk and with a pit of 3-11T a recording pit length, the irradiation time of the recording laser beam is controlled to (n-J)T-alpha(nT) according to the pit length nT to be recorded. Where, n=3-11, J is a constant, alpha(3T)>=alpha(5T)>=...>=2(11T), alpha(3T)>alpha(11T).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mark length recording type optical disk recording apparatus for irradiating a recording surface of an optical disk with laser light to form pits and recording information, and when recording on a phthalocyanine type disk, The amount of deviation from the specified value of the pit length formed while maintaining the recording signal quality is reduced.

[0002]

2. Description of the Related Art There is a CD-WO (CD Write Once) standard as one of recording methods for writable optical disks. This is a write-once recording in the CD format. In this CD-WO standard, the recording pit length is 3 to
11T (1T = 1 / 4.318218 MHz = 231 ns) is used. However, when laser light having a pulse width corresponding to the pit length to be formed is irradiated, pits are actually formed by about 1T longer due to residual heat. Therefore, the so-called (n-
1) Referred to as strategy, as shown in FIG. 2, a pulse width (n-1) T shorter than the pit length to be formed by about 1T.
+ Α (nT), that is, 2T + 3 when forming a 3T pit
0-70ns pulse width, 3T + 20 when recording 4T
-40ns pulse width, 4T when recording 5T-11T
It is stipulated that the recording laser beam is emitted with a pulse width of 10T.

[0003]

In the CD-WO, a K-factor is used as an index showing the amount of deviation of the actually formed pit length from the pit length to be formed. K-factor is defined as follows.

[0004]

[Equation 1] If the K-factor becomes large, a block error will occur during reproduction, so that it is required to be 0.8 or less, for example. In the cyanine-based disc, the (n-
1) If recorded with T + α (nT), this K-factor is 0.8
The following conditions are met. However, when the phthalocyanine-based disc was recorded with (n-1) T + α (nT), it was found that the pit deviation (deviation amount from the specified value of the formed pit length) was increased as shown in FIG. . As for pit deviation, 3T is the standard value ± 40n in the standard.
Although it is required that s and 11T fall within a specified value ± 60 ns, this disc was clearly out of this standard at 3T and 7T to 11T. Therefore, as shown in FIG. 5, it was found that the K-factor increases and a block error may occur.

In order to lower the K-factor, it is necessary to lower the recording power as can be seen from FIG. And K-fa
In order to reduce the ctor to 0.8 or less, it is necessary to record with a power smaller than the proper power range required for recording. However, when recording with a power smaller than the proper power range, pits are not clearly formed, so that the quality of the recording signal is deteriorated and the reproduction error occurrence rate is increased. For this reason, in the phthalocyanine-based disc, if the recording laser light irradiation time is controlled to (n-1) T + α (nT) for recording, the deterioration of the recording signal quality is prevented and the pit length formed from the specified value is prevented. The amount of deviation could not be reduced.

The present invention solves the above-mentioned problems in the prior art, and when recording on a phthalocyanine-based disc, prevents the deterioration of the recording signal quality and deviates from the specified value of the formed pit length. It is an object of the present invention to provide an optical disk recording device capable of reducing the amount.

[0007]

The invention according to claim 1 is
CD-using phthalocyanine dye as recording material
In an optical disk recording apparatus for forming pits having a recording pit length of 3 to 11T on a WO disk, the irradiation time of a recording laser beam is (nJ) T-α (nT) where n is in accordance with the pit length nT to be recorded. = 3 to 11 J: A constant time α (3T) ≧ α (4T) ≧ α (5T) ≧ ... ≧ α (11T) α (3T)> α (11T) It is a thing.

According to a second aspect of the present invention, when the irradiation time control means forms pits of the same length, the higher the recording speed magnification, the more the α for the length of 1T at each speed magnification.
It is characterized by increasing the ratio of (nT).

The invention according to claim 3 further comprises a laser power control means for controlling the recording power of the recording laser beam, wherein the irradiation time control means increases the value of J when the recording speed magnification is low. When the recording speed magnification is high, the value of J is reduced, and the laser power control means is a laser required for forming a predetermined pit length under the irradiation time in which the value of J is adjusted. It is characterized in that the recording laser light is irradiated after adjusting the power.

[0010]

According to the inventor's experiment, when the irradiation time of the recording laser beam was controlled for the phthalocyanine type disc as described in claim 1, even if the recording power was not lowered,
It was found that the amount of pit length deviation could be reduced. Also,
When the recording speed magnification is changed, as described in claim 2, the higher the recording speed magnification, the larger the ratio of α (nT) to the length of 1T at each recording speed magnification. It was found that the amount of pit length deviation can be reduced without lowering the recording power at the magnification. When the recording speed magnification is changed, the value of J is increased when the recording speed magnification is low, and the value of J is decreased when the recording speed magnification is high. Like J
By adjusting the laser power to the value required to form the correct pit length with the irradiation time adjusted, the change in the proper laser power due to the recording speed magnification is suppressed, thereby reducing the jitter and crossing. It was found that the talk signal can be reduced and the recording signal quality can be improved.

[0011]

An embodiment of the present invention will be described below. FIG. 5 shows the overall structure of an optical disk recording / reproducing apparatus to which the present invention is applied. With the input device 28, the recording speed magnification is set by an operator's operation or the like. In response to a command from the system controller 19, the disk servo circuit 16 controls the rotation of the disk motor 12 at a set linear velocity and a constant linear velocity. This constant linear velocity control is for CD
-In case of WO standard, pre-group wobble (Wobbl
Since e) is regulated to be 22.05 kHz, wobble is detected from the output signal of the optical head 13 (it can be detected from the residual portion of the tracking error signal), and this is 22.05 kHz (at 1 × speed. 2 It is realized by controlling the PLL of the disk motor 12 so that the speed becomes 44.1 kHz at double speed and 88.2 kHz at double speed.

The focus servo and tracking servo circuit 18 controls the focus and tracking of the laser light 11 emitted from the semiconductor laser in the optical head 13 according to a command from the system controller 19. Tracking control is performed by detecting the pre-groove formed on the disk 10. The feed servo circuit 17 drives the feed motor 20 according to a command from the system controller 19 to move the optical head 13 in the radial direction of the disk 10.

An input signal to be recorded on the optical disk 10 (CD-WO disk using a phthalocyanine dye as a recording material) is directly input to the data signal forming circuit 22 in the case of a digital signal at a speed according to the recording speed magnification. In the case of an analog signal, it is input to the data signal forming circuit 22 via the A / D converter 24. The data signal forming circuit 22 interleaves the input data to give an error check code, and also gives TOC information and subcode information generated by the TOC and subcode generation circuit 23, EFM-modulates them, and CD standards. The serial data is formed and output at a transfer rate according to the format and the recording speed magnification.

This data is input to the laser generation circuit 25 through the drive interface 15 after being modulated by the data signal correction circuit 26 according to the present invention. The laser generation circuit 25 drives the semiconductor laser in the optical head 13 according to the data signal to irradiate the recording surface of the optical disc 10 with laser light to form pits for recording. The laser power at this time is a value corresponding to the recording speed magnification and the linear velocity as necessary (that is, the laser power to be irradiated to form a predetermined pit length within a predetermined irradiation time).
Commanded by ALPC (Automatic Laser Power Contro
l) The circuit controls the commanded power with high precision. As a result, the optical disc 1 has a CD standard format, transfer rate and linear velocity (1.2 to 1.4 m / s).
The data is recorded with.

The optical disk 10 recorded as described above
When reproduction is performed by irradiating a reproduction laser beam (having a smaller power than that of the recording laser beam) on the read data, the read data is the signal reproduction processing circuit
It is demodulated by the
The A converter 32 converts the analog signal and outputs the analog signal.

FIG. 1 shows a control block of the present invention by the optical disk recording / reproducing apparatus of FIG. The recording speed multiplying factor setting means 28 (the input device 28 in FIG. 5) sets the recording speed multiplying factor through an operator's operation or the like. The rotation control means 16 (disk servo circuit 16 in FIG. 5) rotationally drives the optical disk at this set recording speed magnification. Linear velocity detection means 1
Reference numeral 9 detects a disk wobble from the output signal of the optical head 10 and detects a linear velocity based on the detected disk wobble. Specifically, the data called ATIP signal is FM in the pre-groove.
It is recorded by modulation, especially in the lead-in area.
Since the recording time of the disc is recorded in advance by the TIP signal, the linear velocity can be obtained by back-calculating from the recording time of the disc. As another method, the disc radial direction position of the optical head detected by a rotary encoder attached to the feed motor of the optical head and the disc radial direction and the disc motor mounted on the disc motor are controlled by the disc wobble. It is also possible to calculate the linear velocity from the disk rotation speed detected by a rotary encoder or the like.

The irradiation time control means 26 (data signal correction circuit 26 in FIG. 5) controls the irradiation time of the recording laser beam 11 by modulating the input FEM signal according to the present invention.
Laser power control means 25 (laser generation circuit 2 of FIG. 14
In 5), the laser power of the recording laser beam 11 is controlled so that a predetermined pit length is formed under the set recording speed magnification.

The irradiation time control means 26 controls the irradiation time of the recording laser beam 11 and the laser power control means 25.
The control of the laser power of the recording laser light 11 by means of will be described. The irradiation time control means 26 controls the irradiation time of the recording laser light according to the recording speed magnification and the pit length to be formed as follows. (1) In the case of 1 × speed recording (1T = 231 ns) Irradiation time = (n-1.5) T to (n-1.0) T-
Set to α (nT). At this time, α (nT) is expressed as a ratio (α (nT) / 1T) to 1T (231ns). When α (3T): 0-5%, when α (4T): 0-5% For α (5T) to α (11T): Set to 0%. (2) Double speed recording (1T = 16 ns) Irradiation time = (n-1.0) T to (n-0.5) T-
Set to α (nT). At this time, α (nT) is expressed as a ratio with respect to 1T (116 ns): when α (3T): 0 to 10%, when α (4T): 0 to 10%, α (5T): 0 ~ 5%, α (6T) ~ α (11T):
Set it to 0%. (3) In the case of 4 × speed recording (1T = 58 ns) Irradiation time = (n−0.5) T to (n + 0.1) T−
Set to α (nT). At this time, α (nT) is expressed as a ratio with respect to 1T (58 ns): 0 to 20% for α (3T), 0 to 20% for α (4T): 0 for α (5T): 0 -10%, α (6T): 0-10% α (7T): 0-5%, α (8T): 0-5% α (9T) -α (11T): 0% FIG. 6 is a graph showing the relationship between the recording speed magnification and the irradiation time according to the above settings. Further, the laser power at this time is preferably set in a range (appropriate power range) in which jitter is minimized when recording is performed by setting the irradiation time as described above and changing the recording power variously.
FIG. 7 shows the relationship between the recording power and the jitter for the 1 × speed recording. (A) is the jitter of the pit portion, and (b) is the jitter of the blank portion between the pits. In this case, the shaded range can be set as the appropriate power range. FIG. 8 shows the result of obtaining the minimum power range in this manner for each speed multiplication factor.
According to this, when the recording speed magnification is 2 × speed, the laser power is about 1.4 times at 1 × speed, and at 4 × speed,
The laser power is about twice as high as that at 1 × speed.

In FIG. 8, the chain double-dashed line represents the laser power when the irradiation time is fixed at (n-1) T.
When fixed to (n-1) T, the pit length is formed longer than the specified value when the recording speed magnification is low. Therefore, it is necessary to reduce the recording power by that amount to cancel the tendency to be formed longer. . Further, when the recording speed magnification is high, the pits are formed shorter than the specified value. Therefore, it is necessary to increase the recording power to cancel the tendency of the pit formation. Therefore, if fixed at (n-1) T, it is necessary to greatly change the recording laser power depending on the recording speed magnification.

The irradiation time is set as shown in FIG. 6 and the laser power is set as shown in FIG. 8 to record the EFM signal of the CD format at 1 × speed on the phthalocyanine test sample disc and reproduce the pit. The deviation (deviation amount of the formed pit length from the set value) is shown in FIG.
According to this, it is understood that the conditions of 3T within the specified value ± 40 ns and 11T within the specified value ± 60 ns are satisfied (the two-dot chain line is recorded as (n-1) T + α (nT) in FIG. 3 described above. The characteristics of the case.). Also, at this time, K-fact
or is shown in FIG. According to this, K within the proper power range
It can be seen that the condition that the -factor is 0.8 or less is satisfied (the chain double-dashed line is the characteristic when recorded at (n-1) T + α (nT) in FIG. 4). It was found that the conditions of pit deviation and K-factor are also satisfied by setting the irradiation time as shown in FIG. 6 and the laser power as shown in FIG.

Further, FIG. 11 shows the crosstalk of the reproduced signal when recording is carried out in this way. The two-dot chain line is (n-1) T
This is the crosstalk when fixed and recorded. According to this, it can be seen that by recording with the characteristics shown in FIGS. 6 and 8, the crosstalk is averaged to a relatively small value regardless of the change in the recording speed magnification. As shown in FIG. 6, when the recording speed magnification is low, the irradiation time is shorter than (n-1) T, and when the recording speed magnification is high, the irradiation time is (n-1) T.
-1) By making the length longer than T, the change in the proper power range becomes smaller as compared with the case where (n-1) T is constant as shown in FIG. 8, so that the laser power when the recording speed magnification is high is set. It is considered that this can be suppressed to a low value, which suppresses thermal diffusion in the lateral direction (track width direction) and suppresses an increase in the recording pit width. Further, since the laser power can be made high when the recording speed magnification is low, pits can be clearly formed and the recording signal quality can be improved.

Further, pit jitter and blank jitter when recorded in this way are shown in FIGS. 12 (a) and 12 (b). According to this, it can be seen that both the pit jitter and the blank jitter are averaged to a relatively low value as compared with the case where the recording is fixed at (N-1) T.

In the above embodiment, the case of 1, 2, and 4 × speed was described, but the present invention can be applied to the case of recording at a speed magnification higher than 4 × speed. Further, in the above embodiment, the case of recording on the phthalocyanine type disc has been described. However, when recording on the cyanine type disc, the (nJ) T-α (nT) strategy of the present invention and the conventional method are operated by a switch operation. Of (n-
J) T + α (nT) strategy should be switched so that it can be used.

[0024]

As described above, according to the first aspect of the present invention, it is possible to reduce the deviation amount of the pit length without lowering the recording power, thus preventing the deterioration of the recording signal quality. The shift amount of the pit length can be reduced, and the error occurrence rate of the reproduction signal can be reduced.

According to the second aspect of the present invention, the pit length deviation amount can be reduced without lowering the recording power at each recording speed magnification, so that the recording signal quality is deteriorated at each recording speed magnification. It is possible to reduce the deviation amount of the pit length while preventing the above, and it is possible to reduce the error occurrence rate of the reproduction signal regardless of the recording speed magnification.

According to the third aspect of the present invention, the value of J is increased when the recording speed magnification is low, and the value of J is decreased when the recording speed magnification is high. Since the laser power is adjusted to the laser power required to form the correct pit length with the adjusted irradiation time, it is possible to suppress changes in the appropriate laser power due to the recording speed magnification, which reduces jitter. However, it is possible to reduce crosstalk and improve the recording signal quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention applied to the optical disc recording apparatus of FIG.

FIG. 2 is a time chart showing a recording method according to a conventional (n-1) strategy.

FIG. 3 shows a conventional phthalocyanine-based disk (n-
1) A characteristic diagram showing a shift amount of a pit length when recording is performed by a strategy.

FIG. 4 shows a conventional phthalocyanine-based disk (n-
1) It is a characteristic diagram showing a K-factor when recording with a strategy.

FIG. 5 is a block diagram showing an embodiment of an optical disc recording / reproducing apparatus to which the present invention is applied.

FIG. 6 is a characteristic diagram showing an embodiment of irradiation time control according to the present invention.

FIG. 7 is a characteristic diagram showing changes in jitter depending on recording power when recording is performed at 1 × speed with the irradiation time characteristic of FIG. 6.

8 is a characteristic diagram showing appropriate recording power at each recording speed magnification when recording is performed with the irradiation time characteristic of FIG.

9 is a characteristic diagram showing a deviation amount of a pit length when recording is performed with the irradiation time characteristic of FIG. 6 and the recording power characteristic of FIG.

10 is a characteristic diagram showing the irradiation time characteristic of FIG. 6 and the K-factor when recording is performed with the recording power of FIG.

11 is an irradiation time characteristic of FIG. 6 and a crosstalk characteristic when recording is performed with the recording power of FIG.

12 is an irradiation time characteristic of FIG. 6 and a jitter characteristic when recording is performed with the recording power of FIG.

[Explanation of symbols]

 10 Optical Disc (Phthalocyanine Disc) 11 Recording Laser Light 16 Rotation Control Means 25 Laser Power Control Means 26 Irradiation Time Control Means 28 Recording Speed Magnification Setting Means

Claims (3)

[Claims] 1. An optical disc recording apparatus for forming pits having a recording pit length of 3 to 11T on a CD-WO disc using a phthalocyanine dye as a recording material, the irradiation time of a recording laser beam, and the pit length nT to be recorded.
Depending on (nJ) T-α (nT) where n = 3 to 11 J: constant α (3T) ≧ α (4T) ≧ α (5T) ≧ …… ≧≧ α (11T) α (3T)> An optical disk recording device comprising irradiation time control means for controlling to α (11T). 2. When the irradiation time control means forms pits of the same length, the higher the recording speed magnification, the larger the ratio of α (nT) to the length of 1T at each speed magnification. The optical disk recording device according to claim 1, wherein 3. A laser power control means for controlling the recording power of the recording laser beam is further provided, and when the irradiation time control means has a low recording speed magnification, the value of J is increased to increase the recording speed magnification. When the value is high, the value of J is reduced, and the laser power control means adjusts the laser power to a value required for forming a predetermined pit length under the irradiation time in which the value of J is adjusted, The optical disc recording method according to claim 1, wherein the recording laser beam is irradiated.