JP2003331539A - Disk player and disk playing-back method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk player and a disk playing-back method capable of realizing the highly accurate data reproduction by executing the exact data process to cope with a defect. <P>SOLUTION: The disk player includes a pickup 3 for reading out the data recorded on a disk 1 and a defect detecting circuit 9 for detecting the defect of the disk 1, and such a feature is provided therein that a measuring part 17 of disk rotating time for calculating the rotating time required for scanning by the pickup 3 one round only from the optional position on the disk 1 and a shift register 15 for predicting the timing when the defect is again to be detected based on the rotating time calculated by the measuring part 17 in the case the defect is detected by the defect detecting circuit 9 and for increasing the detection sensitivity of the defect detecting circuit 9 responding to the predicted timing are furnished. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc reproducing apparatus and a disc reproducing method for reproducing data recorded on a disc.

[0002]

2. Description of the Related Art Conventionally, defects (defects such as scratches) generated on a disk have been detected by monitoring data read from the disk.

Here, in the conventional disc reproducing apparatus, the operation corresponding to the defect is started after the defect is detected.

[0004]

However, in the conventional disc reproducing apparatus, since the loss time occurs between the detection and the start of the corresponding operation as described above, the accurate data processing for the defect is not executed. There was a problem.

The present invention has been made to solve the above problems, and a disc reproducing apparatus and a disc reproducing device for realizing highly accurate data reproduction by executing accurate data processing corresponding to a defect. The purpose is to provide a method.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to include read means for scanning a loaded disk to read data recorded on the disk, and defect detection means for detecting a disk defect by reading the data. In the disc reproducing apparatus, a rotation time calculation unit that calculates a rotation time required for the reading unit to scan only one round from an arbitrary position on the disc, and a defect detection unit detects a defect, Based on the rotation time calculated by the rotation time calculation means, the timing for detecting a defect again is predicted, and a control means for enhancing the detection sensitivity of the defect detection means according to the predicted timing is provided. This is achieved by providing a disc reproducing apparatus that

According to such means, the control means enhances the defect detection sensitivity at the timing at which the defect detection is predicted, so that the defect detection means can detect the defect reliably and at high speed.

Here, the rotation time calculating means measures the rotation time at at least two points on the disk having different distances from the center, and the rotation time measured at at least two points is used to determine an arbitrary time on the disk. The rotation time at the position can be calculated.

On the other hand, since a defect detected once has a high probability of being detected again even after the disk has made one revolution, the control means is generated by the defect detection means when the defect is detected by the defect detection means. The defect can be detected reliably and at high speed by receiving a detection signal for detecting the detection signal and supplying a control signal for increasing the detection sensitivity to the defect detection means when the rotation time elapses from the time when the detection signal is received.

Another object of the present invention is a disk reproducing method including the steps of scanning a mounted disk to read data recorded on the disk, and detecting a disk defect by reading the data. Based on the rotation time calculated in the rotation time calculation step, a rotation time calculation step of calculating the rotation time required to scan only one round from an arbitrary position on the disk, and when a defect is detected, And a control step of predicting the timing at which a defect is detected again and increasing the detection sensitivity of the defect in accordance with the predicted timing.

According to such means, the defect detection sensitivity is enhanced at the timing when the defect detection is predicted, so that the defect can be detected reliably and at high speed.

Here, the calculation of the rotation time is easily realized by measuring the rotation time at at least two points on the disk having different distances from the center and using the rotation time measured at at least two points. be able to.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts.

FIG. 1 is a block diagram showing the configuration of a disc reproducing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the disc reproducing apparatus according to the present embodiment is
Pickup 3, RF amplifier 5, DSP (digital signal processor) 20, microcomputer 30, and driver 1
3 is provided. The DSP 20 includes a subcode detection circuit 7, a defect detection circuit 9 and a servo processing unit 11, and the microcomputer 30 includes a CPU 14, a shift register 15 and a disk rotation time measuring unit 17.

Here, the pickup 3 is connected to a driver 13 which will be described later, irradiates the mounted optical disc 1 with a laser beam, detects the reflected light from the pit formed on the optical disc 1, and converts it into an electric signal. . Also, R
The F amplifier 5 is connected to the pickup 3 and amplifies the electric signal. Further, the DSP 20 is connected to the RF amplifier 5, the microcomputer 30 is connected to the DSP 20, and the driver 1
3 is connected to the DSP 20.

Further, the subcode detection circuit 7 and the defect detection circuit 9 are connected to the RF amplifier 5, and the defect detection circuit 9 is also connected to the shift register 15.
The servo processing unit 11 and the shift register 15 are connected to the defect detection circuit 9, and the servo processing unit 11 is controlled by the CPU 14 included in the microcomputer 30. The servo processing unit 11 is also connected to the RF amplifier 5, and the shift register 15 is also connected to the disk rotation time measuring unit 17. Further, the disk rotation time measuring unit 17 is connected to the subcode detection circuit 7, and the driver 13 is connected to the servo processing unit 11.

In the disc reproducing apparatus having the above-mentioned structure, the focus error signal F is output from the RF amplifier 5.
E and the tracking error signal TE are the servo processing unit 11
The servo control of the pickup 3 is executed according to these signals. The focus error signal F
E indicates whether or not the focused laser beam is focused on the pit formed on the surface of the optical disc 1, and the tracking error signal TE indicates whether or not the laser beam scans a track on which data is recorded. Is a signal indicating.

Then, the driver 13 is the servo processor 11
The focal length of the pickup 3 is adjusted according to the focus signal FCS supplied from the optical pickup, and the position of the pickup 3 in the radial direction of the disc 1 is adjusted according to the tracking signal TRK.

Here, if there is a defect on the disk 1, an abnormal focus error signal FE and tracking error signal TE are generated due to the reflected light from the disk 1, so the scanning position of the pickup 3 is generated. May go off the legitimate track.

Therefore, in the disc reproducing apparatus according to the embodiment of the present invention, the presence or absence of a defect on the disc 1 is monitored, and when a defect is detected, measures such as maintaining the servo control at that time are taken. To be done.
At this time, the defect detection needs to be performed as quickly and accurately as possible.

Therefore, in the present disc reproducing apparatus, the time required for the scanning of the pickup 3 to make one revolution on the disc 1 is calculated in advance as a function of the scanning position, and next, depending on the time when a defect is detected during data reproduction, Predict when a defect will be detected. Then, at the predicted timing, the defect detection sensitivity is increased to detect the defect quickly and accurately.

The operation of the disc reproducing apparatus shown in FIG. 1 will be described below in detail with reference to the flow charts of FIGS. 2 and 3. First, as described above, the time taken for the pickup 3 to make one rotation under a constant linear velocity (hereinafter,
In order to calculate "rotation time" as a function of the scanning position, the rotation time is measured at each of at least two points having different distances from the center of the disk 1. Here, the measurement is executed by the control of the microcomputer 30, that is, the control of the servo processing unit 11 by the program executed by the CPU 14.

Specifically, as shown in FIG. 2, first, in step S1, the sub-code detection circuit 7 is recorded at a certain scanning position on the disk 1 based on the RF signal supplied from the RF amplifier 5. The subcode Q is detected, and the absolute time information AT is read by the subcode Q.

Next, in step S2, the scanning position of the pickup 3 is jumped to the reverse side (inner peripheral side) by one track as shown in FIG. As shown in FIG. 4, in the reproducing operation of the data recorded on the disc 1, the pickup 3 spirally scans the disc 1 from the inner circumference to the outer circumference.

Then, in step S3, the disk rotation time measuring unit 17 measures the time until the subcode Q read in step S1 is detected based on the absolute time information AT supplied from the subcode detection circuit 7. To do. In this way, in step S4, it is determined whether or not the measurement of the rotation time is completed at the two different points, and if it is completed, the process proceeds to step S5.

Here, the case where the measurement is performed at two different points, for example, the point P _A and the point P _B will be described.
The distance (disc radius) from the disc center of the point P _A is r _A , the absolute time information read at the point P _A is Q _A , the rotation time at the point P _A is t _A , and the point P _B the disk radius _{r B, Q B} the absolute time information read at point _{P B, t B} the rotation time at the point _{P B}
And

The radius r of the disk 1 and the length l of one round are proportional to each other according to the following equation (1).

[0028]

[Equation 1]

Further, as described above, the linear velocity is constant (velocity v).
When the disk 1 is scanned with, the rotation time t and the length l of the above-mentioned one round are proportional as expressed by the following equation (2).

[0030]

[Equation 2]

Therefore, from the above equations (1) and (2),
The following expression (3) holds.

[0032]

[Equation 3]

From this, the rotation time t and the radius r (or
The circumference l) of the disk 1 is proportional to that shown in FIG.
Have. In addition, in FIG._AIs point P_AIn
Disk 1 circumference, l_BIs point P_BDisc 1 circle at
Each lap is shown. Here, the track of disk 1 is
Assuming that it consists of a number of concentric circles, the point P_AAnd point P _B
I think there is a track consisting of multiple concentric circles between
Be done. At this time, point P _ATo point P_BAll up to
Track playback time T_ABIs the radius r_ATo radius r_BWell
The integrated value of the rotation time t between, that is, shown in FIG.
In the graph shown, it is indicated by the shaded area.

Therefore, the reproduction time T _AB is expressed by the following equation (4).

[0035]

[Equation 4]

Since the reproduction is performed at 1 × speed, the reproduction time T _AB is the absolute time information Q read at the point P _A.
A and the absolute time information Q _B read at the point P _B are shown by the following equation (5).

[0037]

[Equation 5]

Therefore, the relationship of the following expression (6) is established by the above expressions (4) and (5).

[0039]

[Equation 6]

Next, an arbitrary point P on the disk 1_X(radius
r_X, Absolute time information read Q _X) When rotating
Interval t_XTo calculate. First, point P_ATo point P_XUp to
Considering the playback time of the following equation (7),
Relationship is established.

[0041]

[Equation 7]

Further, the proportional relation of the following equation (8) is established from the relation of the equation (3).

[0043]

[Equation 8]

Here, the relation of the equation (8) can be rewritten as the following equation (9).

[0045]

[Equation 9]

By substituting the equation (9) into the equation (7), the following equation (10) is obtained.

[0047]

[Equation 10]

Here, if (r _B −r _A ) / 2 is set to K, the above equations (6) and (10) can be rewritten as the following equation (11).

[0049]

[Equation 11]

Therefore, when the rotation time t _X is obtained from the equation (11), the following equation (12) is obtained.

[0051]

[Equation 12]

From this, by substituting the absolute time information Q _X read at the point P _X into the equation (12), the rotation time t _X at the point P _X can be obtained. It should be noted that the absolute time information Q _X shown by equation (12)
The relationship between the rotation time and the rotation time t _X is shown in FIG.

Therefore, when a defect is detected by the defect detection circuit 9 during normal reproduction of the disc 1, it is calculated based on the absolute time information Q _X read at the point P _X where the defect is detected. The timing at which the defect is detected again is predicted from the rotation time t _X , and the sensitivity of the defect detection circuit 9 is increased before and after the predicted timing.

In the following, step S shown in FIG.
The operation after the start of reproduction in 5 will be specifically described. When actually reproducing the disc 1, the defect is not always detected only once per one rotation. That is, since defects are randomly generated on the disk 1, it is difficult to perform the above-described operation on all of these defects by hardware or software.

Therefore, as shown in FIG. 7, the recording area of the disk 1 is divided into several zones, for example, 16 zones z1 to z16, and the defect prediction operation is executed in units of the zones. In this case, the shift register 15 shown in FIG.
It is configured by a 16-bit shift register including individual storage areas R1 to R16.

The disk rotation time measuring unit 17 measures the rotation time at the current scanning point of the pickup 3 by the above method according to the absolute time information AT supplied from the subcode detection circuit 7, and the rotation time is measured. 1/1 of time
A clock signal having a cycle of 6 is generated and supplied to the shift register 15.

As a result, step S6 shown in FIG.
In, the shift register 15 determines whether or not the disk 1 has made (1/16) turns according to the clock signal supplied from the disk rotation time measuring section 17, and (1/16)
If the circuit has completed the circuit, the process proceeds to step S7, and if the circuit has not completed (1/16) circuit, the process proceeds to step S11.

On the other hand, the defect detection circuit 9 detects a defect on the basis of the RF signal supplied from the RF amplifier 5, and when the defect is detected, the defect detection signal DD is generated to generate the defect detection signal DD and the servo processor 11 and the shift register 15. Supply to.

Therefore, in step S11 shown in FIG. 3, the shift register 15 determines whether or not a defect is detected according to the defect detection signal DD. When it is determined that the defect is detected, the shift register 15 sets a flag in the storage area R1 of the most significant bit in step S12 according to the supplied defect detection signal DD. As a result, the defect detection result is sequentially input to the shift register 15 every time the disk 1 makes a (1/16) round.

On the other hand, if it is determined in step S11 that no defect is detected, step S1
Go to 3.

In step S13, the CPU 14 determines whether or not the reproduction operation is to be ended. If the reproduction operation is to be continued without being ended, the process returns to step S6.

Then, in step S7, the shift register 15 shifts the flags stored in the storage areas R1 to R16, respectively, by one bit lower. When the data is further shifted with the flag stored in the least significant bit (storage area R16), the defect prediction signal DP is supplied from the shift register 15 to the defect detection circuit 9.

Therefore, as shown in FIG. 7, for example, when the defect Pd is detected in the zone z1 of the disk 1 and the flag is set in the storage area R1 of the shift register 15, the disk 1 makes one revolution and is again read. Zone z
Storage region R1 of the shift register 15 when reproducing 1
6 outputs the defect prediction signal DP.

As a result, the shift register 15 always indicates to the defect detection circuit 9 the defect detection result of the disk 1 before one rotation.

Then, in step S8, the defect detection circuit 9 determines whether or not the defect prediction signal DP is received from the shift register 15. If it is determined that the defect prediction signal DP is received, the process proceeds to step S9, and it is not received. If so, the process proceeds to step S10.

Here, the defect detection circuit 9 sets the defect detection sensitivity to a normal value in step S10, and increases the detection sensitivity in step S9. In addition,
The adjustment of the detection sensitivity is performed, for example, by raising or lowering the threshold value regarding the strength of the supplied RF signal.

As described above, according to the disc reproducing apparatus according to the embodiment of the present invention, the defect prediction signal DP indicating to the defect detecting circuit 9 that the defect is detected before one rotation of the disc 1 is transmitted to the shift register 1.
5, the defect detection circuit 9 increases the defect detection sensitivity in accordance with the defect prediction signal DP, so that the defect can be detected more reliably and faster than in the conventional case.

As a result, at the time when the defect is detected, the servo control immediately before the time can be maintained instantaneously, so that the accuracy of the compensating operation for avoiding the influence of the defect and thus the entire reproducing operation can be improved. You can

The number of divided zones shown in FIG. 7 is the same as the number of storage areas included in the shift register 15 shown in FIG. 8, but the number can be set arbitrarily.

Further, the above-mentioned defect prediction signal DP
In order to provide a margin, the pickup 3 may be supplied to the defect detection circuit 9 not only at the timing when the pickup 3 scans the zone where the defect is predicted to occur, but also at the timing when it scans the zones before and after the zone.

[0071]

According to the disc reproducing apparatus and the disc reproducing method of the present invention, since the defect detection sensitivity is enhanced at the timing at which the defect detection is predicted,
Since the defect can be detected reliably and at high speed, the accuracy of the compensating operation for avoiding the influence of the defect and thus the entire reproducing operation can be improved.

[0072]

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a disc reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the disc reproducing apparatus shown in FIG.

FIG. 3 is a flowchart showing a continuation of the operation shown in FIG.

FIG. 4 is a diagram illustrating an operation of the disc reproducing apparatus shown in FIG.

FIG. 5 is a graph showing the relationship between the disc radius and the time required for one revolution of the disc.

FIG. 6 is a graph showing the relationship between the absolute time and the time required for one rotation of the disk.

7 is a first diagram illustrating the operation shown in FIGS. 2 and 3. FIG.

FIG. 8 is a second diagram illustrating the operation shown in FIGS. 2 and 3;

[Explanation of symbols]

1 optical disk, 3 pickups, 5 RF amplifier, 7
Subcode detection circuit, 9 defect detection circuit, 1
1 servo processing unit, 13 driver, 14 CPU, 1
5 shift register, 17 disk rotation time measurement unit,
20 DSP (Digital Signal Processor), 30
Microcomputer.

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) G11B 20/18 576 G11B 20/18 576C 7/004 7/004 A 20/10 20/10 C 321 321Z

Claims (5)

[Claims] 1. A disc reproducing apparatus comprising: a reading unit that scans a mounted disc to read data recorded on the disc; and a defect detecting unit that detects a defect of the disc by reading the data, The reading unit is 1 from an arbitrary position on the disc.
Rotation time calculation means for calculating the rotation time required to scan only the circumference, and when the defect is detected by the defect detection means, based on the rotation time calculated by the rotation time calculation means, A disc reproducing apparatus, comprising: a control unit that predicts a timing at which the defect is detected again, and that increases the detection sensitivity of the defect detection unit according to the predicted timing. 2. The rotation time calculation means measures the rotation time at at least two points on the disk having different distances from the center, and the disk is measured according to the rotation time measured at the at least two points. The disc reproducing apparatus according to claim 1, wherein the rotation time at an arbitrary position above is calculated. 3. The control means receives a detection signal generated by the defect detection means when the defect is detected by the defect detection means, and the rotation time from the time when the detection signal is received. 2. The disc reproducing apparatus according to claim 1, wherein a control signal for increasing the detection sensitivity is supplied to the defect detecting means when the time elapses. 4. A disc reproducing method comprising: a step of scanning a loaded disc to read data recorded on the disc; and a step of detecting a defect of the disc by reading the data. A rotation time calculation step of calculating a rotation time required to scan only one round from an arbitrary position above, and based on the rotation time calculated in the rotation time calculation step when the defect is detected And a control step of predicting the timing at which the defect is detected again and increasing the detection sensitivity of the defect according to the predicted timing. 5. The rotation time calculation step comprises:
5. The method according to claim 4, further comprising: measuring the rotation time at a point; and calculating the rotation time at an arbitrary position on the disk according to the rotation time measured at the at least two points. Disc playback method.