JP2907027B2 - Optical disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device,
In particular, the present invention relates to an optical disk device having a three-beam optical pickup.

[0002]

2. Description of the Related Art In an optical disk apparatus for recording and reproducing data, in order to ensure the reliability of the recorded data, after recording the data, it is necessary to determine whether or not the data has been correctly recorded by reproducing the data once. A verify operation for checking is performed, and if an error occurs as a result, processing such as recording again in the alternative area is performed.

[0003] As a method of the verify operation, after data is recorded over a predetermined range by a recording / reproducing beam, the optical pickup is returned to a recording start position in the predetermined range, and then the data is reproduced by the recording / reproducing beam. There is a way to play. As another verification operation method, a method of providing an optical pickup for verification separately from an optical pickup for recording and reproducing data,
A method is considered in which a laser beam from the same laser light source is separated into two or three laser beams by a diffraction grating, and one beam is used as a data recording / reproducing beam and the other beam is used as a verifying beam.

[0004]

In the method using the same beam for data recording and verification, the optical pickup is returned to the recording start position after recording is completed, and reproduction is performed. In addition to the rotation waiting time, the time required for simply performing recording only is required twice or more, and there is a problem that the data processing efficiency of the host connected to the optical disk device is reduced.

A method of providing an optical pickup for verifying separately from an optical pickup for recording and reproducing data can solve the problem of data processing efficiency, but causes a problem of a complicated apparatus and an increase in cost. Further, the method of separating a laser beam from the same laser light source into a recording / reproducing beam and a verifying beam by a diffraction grating complicates the optical system of the optical pickup. Especially C
In a three-beam type optical disk device such as a D-R device having a main light beam for data recording / reproduction and a sub light beam before and after for generating a tracking signal, it is necessary to further provide a verifying beam for the optical system. The complexity and the accompanying cost increase become a problem.

[0006] A CD-R is a write-once recording medium, has the same size as a CD, and has compatibility compatible with a normal CD player. In a CD-R device that performs recording and reproduction of a CD-R, recording is performed by light modulation that changes the intensity of light. That is, the dye of the recording layer is melted by irradiating a laser beam, and pits are formed in the grooves of the polycarbonate substrate. In a CD-R device, a running OPC (Optimum Power Control) for monitoring return light during recording is used in order to keep the laser intensity at the time of recording optimal.
).

It is conceivable to perform verification using the return light during recording. However, when monitoring the data of a pit that is currently being formed, the amount of return light greatly changes, and the pit is gradually heated by the heat of the laser light. Therefore, it is impossible to correctly read the recorded data from the return light because the shape of the pit at the time of monitoring by the return light and the pit completely formed after a lapse of time have different shapes. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a three-beam type optical disk apparatus capable of performing an efficient verify operation with a simple configuration without complicating the apparatus. With the goal.

[0009]

An optical disk apparatus according to the present invention separates a light beam emitted from one light source into a main light beam and a sub light beam, irradiates the optical disk with the main light beam, and Before and after the main light beam in the scanning direction of the light beam, the main light beam in the radial direction of the optical disk.
The main light beam is used to irradiate the sub light beam with a half track shifted in opposite directions to each other to perform data recording and reproduction, and the sub light beam or both the main light beam and the sub light beam are used. an optical disk apparatus for generating a tracking error signal using, in the secondary light beam
Of the main light beam out of the reflected light from the disk
The rack and the track adjacent to the scanning track.
Divided into two parts to detect each part
Light detector and each part of the light detector
Of the detected signals located behind the main light beam.
The sub-light beam on the main light beam scanning track
From the detection signal obtained from the portion,
To the unrecorded track of the sub-light beam
Data detecting means for subtracting a detection signal obtained from such a part to detect data recorded on an optical disk by the main light beam, and error determining means for determining an error in the data detected by the data detecting means comprising a structure having and.

[0010]

According to the present invention, the data recorded immediately before on the optical disk by the main light beam can be detected by the data detecting means by using the sub light beam located behind the main light beam. In the error determination means, the detected data can be compared with correct data, or an error can be determined using an error correction code in the data.

According to the present invention, during the data recording operation by the main light beam, the data can be reproduced by the rear auxiliary light beam to perform the verify operation, and the data processing efficiency is not reduced by the verify operation. . Also, 3
Since the reproduction data for verification can be obtained by using the rear auxiliary light beam originally existing in the beam type optical disk device, a verification pickup is provided in addition to the recording / reproduction pickup, or the verification beam is provided. There is no need to provide an optical system for separation.
For this reason, the structure of the three-beam optical disk device that performs the verify operation can be simplified, and the size and cost of the device can be reduced. Also, move the beam back and forth.
Not only half a track from the main light beam
While the leading or trailing secondary light beam
Unrecorded track from the detection result of dividing the
From the secondary light beam that follows the main light beam
The modulation component is obtained by subtracting the component of the unrecorded track.
By regenerating the signal by removing it,
Only signal components can be extracted.

[0012]

In the case of a write-once disc such as a CD-R, the amount of reflected light changes before and after recording. Therefore, during recording, the amount of reflected light differs between the preceding side spot and the following side spot. The three-beam method that takes the difference has a disadvantage that an offset occurs. Therefore,
In a CD-R device, a tracking error signal is calculated using a differential push-pull method.

FIG. 1 is an explanatory diagram of an optical system of an optical pickup using a differential push-pull method, and FIG. 2 is an explanatory diagram of a circuit for generating a beam arrangement and a tracking error signal. As shown in FIG. 1, after the light beam emitted from the laser light source 12 passes through the collimator lens 13,
The light is split into three beams of a main beam, a leading beam, and a trailing beam by the diffraction grating 14, and is irradiated onto the optical disk 25 via the beam splitter 15 and the objective lens 16. Each beam reflected by the optical disk 25 passes through the objective lens 16, the beam splitter 15, and the lens 17,
The light enters the photodetectors 21, 22, 23, respectively, and the reflected light of each beam is detected.

As shown in FIG. 2, tracks TR are formed on the optical disk 25 at a constant track pitch P. As shown in FIG. 2, on the optical disk 25, the side spots S ₃ are arranged by the trailing beam and side spots S ₂ by the main spot S ₁ and the preceding beam by the main beam. The side spot S ₂ is located in the spot scanning direction (arrow A in FIG. 2) with respect to the main spot S ₁ .
Is positioned on the front side with respect to the side spot S ₃
Is the main spot S _1, is disposed on the rear side. The side spots S ₂ and S ₃ are arranged so as to be shifted from the main spot S _{1 in} the radial direction (X ₁ and X ₂ directions) of the optical disk by half the track pitch.

In the example of FIG. 2, n-1, n, n
The tracks TR are formed in the order of +1 and the main spot S
₁Is located on track n, and the side spot
S_TwoIs shifted a half track toward the inner circumference side,
Side spot S_ThreeAre placed a half track off the outer circumference
Have been. Main spot S by main beam₁, Ahead
Side spot S by row beam _Two, By following beam
Side spot S_ThreeEach reflected beam is a light detector
21, 22, and 23.

The optical detectors 21, 22, and 23 are divided into two parts, a left part and a right part, which detect the inner and outer beams in the radial direction of the disk, respectively. Detection signals A and B on the left and right of the photodetector 21 by the reflected beam from the main spot S ₁ are converted by a differential amplifier 31 into a differential signal TE 1 =
AB is taken. Side spot left and right detection signals E photodetectors 22 by the reflected beam from the S _2, F is
The difference signal TE2 = EF is obtained by the differential amplifier 32.
Left and right detection signals G side spots S ₃ photodetector 23 by the reflected beam from, H is the difference signal TE3 = G-H is taken by the differential amplifier 33.

The difference signal TE3 is amplified by an amplifier 34 to adjust the signal level, and is added to the difference signal TE2 by an adder 35. This added signal is amplified by an amplifier 36 to adjust the signal level, and then amplified by a differential amplifier 3.
At step 7, the difference is subtracted from the difference signal TE1. In this way,
From the differential amplifier 37, a tracking error signal from which the offset has been removed is generated.

In a CD-R device, this tracking error
-Using the signal, the main spot S ₁The track exactly
Tracking control is performed to match. FIG.
FIG. 2 shows a configuration diagram of a verifying circuit of the first embodiment. data
The detecting means includes an optical detector 23, a differential amplifier 41, and
It comprises a comparator 42. Also, delay circuit
45 and the comparison determination circuit 43 and the signal processing circuit 44, respectively.
Corresponds to an error determination unit.

The differential amplifier 41 and the inverting amplifier 51 correspond to the differential amplifier 33 in FIG. 2, and the differential signal TE3 = G−
H is output from the inverting amplifier 51. Data is sequentially recorded from the inner track to the outer track of the optical disk 25. Tracks n-1 and n indicated by oblique lines in FIG. 3 are recorded tracks. In Figure 3, for ease of understanding, the main spot S _1, the side spots S _2, photodetectors 21 and 22 to the position of the S _3,
23 are described. Each spot moves in the direction A with respect to the optical disc 25.

When data is recorded by forming pits on n tracks as needed by the main spot S ₁ of the main beam, the signal of the recorded portion recorded immediately before this is recorded by the side spot S ₃ of the succeeding beam. It can be reproduced as crosstalk. Thus, the detection signal G on the left side of the photodetector 23 that detects the reflected light of the following beam
Contains the signal of the recorded portion recorded immediately before. On the other hand, the detection signal H on the right side of the optical detector 23 does not include the signal of the recorded portion.

Further, the signal of the recorded portion of the leading beam side spots n-1 track by S ₂ is reproduced as crosstalk. As a result, the detection signal E on the left side of the photodetector 22 for detecting the reflected light of the preceding beam includes n
-1 The signal of the recorded portion of track 1 is included. On the other hand, the detection signal F on the right side of the optical detector 22 does not include the signal of the recorded portion.

In order to record data using the main beam, the light beam emitted from the laser light source 12 is intensity-modulated. For this reason, the detection signals E, F,
The detection signals G and H by the following beam also include this modulation component. Therefore, the differential amplifier 41 calculates the difference HG of the detection signal, thereby canceling out the modulation component and extracting only the signal component of the recorded portion of the track n. Thus, the differential amplifier 41 can easily extract only the signal component of the recorded portion.

The difference signal H-G taken out as a reproduced RF signal in the differential amplifier 41 is waveform-shaped into a rectangular wave is compared with a reference voltage V _R at the comparator 42. The binary reproduced signal whose waveform has been shaped is supplied to the comparison determination circuit 43 and the signal processing circuit 44. In the comparison judgment circuit 43,
Each data in the reproduced signal reproduced by the succeeding beam,
Comparing the respective data in the recording signal (EFM signal) f _m used for the recording by the main beam performs error determination.

Here, the following beam corresponds to the main beam.
And is located behind by a distance L, the reproduced signal is
Recording signal f_mTime t = L / v (v is the optical disc
(The linear velocity of the lock 25). So,
The delay is delayed by this time t in the
Recording signal f_mIs supplied to the comparison determination circuit 43. ratio
The comparison judgment circuit 43 compares each data in the reproduced signal with the EFM data.
Adjusted recording signal f _mThe corresponding data in
It is. As a result of this comparison, within a predetermined time,
Error occurs, or if more than the specified number of errors
If an error occurs, the data in the recorded
It is determined, and the recorded portion is determined to be a defective area.

The reproduced signal supplied to the signal processing circuit 44 is subjected to EFM demodulation, error detection is performed by a CRC check, and error determination of data in a recorded portion is performed. Note that the configuration may be such that only one of the error determination by the comparison determination circuit 43 and the error determination by the signal processing circuit 44 is performed.

Also, a configuration using a difference signal FG instead of the difference signal HG can be adopted. As described above, in the first embodiment, during the data recording operation by the main beam, the data can be reproduced by the succeeding beam to perform the verify operation, and the data processing efficiency can be reduced by the verify operation. Absent.

Also, since a reproduction signal for verification can be obtained by using the succeeding beam originally present in the three-beam optical disk apparatus, a verification pickup may be provided in addition to the recording / reproduction pickup, or There is no need to provide an optical system for separating the verification beam. Therefore, the structure of the three-beam type CD-R device that performs the verify operation can be simplified, and the size and cost of the device can be reduced.

FIG. 4 is a block diagram showing a verifying circuit according to a second embodiment of the present invention. 4, the same components as those in FIG. 3 are denoted by the same reference numerals, and the description will be appropriately omitted. The data detecting means includes the light detector 23, the inverting amplifier 46, and the comparator 42. Further, each of the delay circuit 45, the comparison determination circuit 43, and the signal processing circuit 44 corresponds to an error determination unit.

When data is recorded by forming pits on n tracks as needed by the main spot S ₁ of the main beam, the signal of the recorded portion recorded immediately before this is recorded by the side spot S ₃ of the succeeding beam. It can be reproduced as crosstalk. Thus, the detection signal G on the left side of the photodetector 23 that detects the reflected light of the following beam
Contains the signal of the recorded portion. On the other hand, optical detector 2
The detection signal H on the right side of 3 does not include the signal of the recorded portion. As described above, the detection signals G and H include a modulation component.

The inverting amplifier 46 includes an operational amplifier 47, a resistor
R₁, Negative feedback resistor R_Two, R_Three, Analog switch 48?
It is composed of Negative feedback resistor R that determines the degree of amplification_Two, R_Three
Is switched by the analog switch 48. Anna
The log switch 48 outputs the recording signal f_mControlled by
And the recording signal f_mIs 0 when the data of
Negative feedback resistor R_ThreeSwitch to the recording signal
f_mIs "1", a negative
Feedback resistor R _TwoSide.

[0031] Thus, since in accordance with the data of the recording signal f _m is switched amplification degree of the inverting amplifier 46, the inverting amplifier 46 which is supplied with the detection signal G is able to output a signal obtained by removing the modulation component it can. As described above, the inversion amplifier 46 can easily extract only the signal component of the recorded portion. The output signal of the inverting amplifier 46 is waveform-shaped into a rectangular wave is compared with a reference voltage V _R at the comparator 42. The binary reproduced signal whose waveform is shaped is
The signal is supplied to the comparison judgment circuit 43 and the signal processing circuit 44.

As described in the first embodiment, the comparison / decision circuit 43 compares the data in the reproduced signal reproduced by the succeeding beam with the recording signal delayed by the time t by the delay circuit 45 to have the same phase. (EFM signal) corresponding data and then one by one comparison in f _m, performs error judgment of the data of the recorded portion which is recorded immediately before. Also, the signal processing circuit 4
4 is subjected to EFM demodulation.
An error detection is performed by the C check, and an error determination of the data in the recorded portion is performed.

The configuration may be such that only one of the error judgment by the comparison judgment circuit 43 and the error judgment by the signal processing circuit 44 is performed. As described above, in the second embodiment, similar to the first embodiment, during the data recording operation by the main beam, the data can be reproduced by the succeeding beam and the verify operation can be performed. There is no reduction in processing efficiency.

Also, since a reproduction signal for verification can be obtained by using the succeeding beam originally present in the three-beam type optical disk apparatus, a verification pickup may be provided in addition to the recording / reproduction pickup, or There is no need to provide an optical system for separating the verification beam. Therefore, the structure of the three-beam type CD-R device that performs the verify operation can be simplified, and the size and cost of the device can be reduced.

Although only the detection signal G is used in the above example, a configuration using an H + G signal instead of the detection signal G may be used. In the second embodiment, since only the detection signal (the detection signal G in FIG. 4) including the signal of the track being recorded by the main beam is used among the detection signals of the succeeding beam, Even when data is recorded on an adjacent outer track and another detection signal (detection signal H in FIG. 4) by the succeeding beam includes a signal component of the adjacent track, a reproduction signal for verification can be obtained correctly. Can be. Therefore, the present invention can be applied to an optical disc recording / reproducing apparatus in which data may be recorded on an outer adjacent track such as an MD.

FIG. 5 is an explanatory diagram relating to a signal detection portion of a verifying circuit according to a third embodiment of the present invention. In FIG. 5, for simplicity, the light detectors 21, 22, and 23 corresponding to the positions of the main spot and the side spot are shown. In the third embodiment, the side spot of the succeeding beam is shifted from the main spot of the main beam by half a track toward the inner circumference, and the side spot by the preceding beam is shifted from the main spot by a half track to the outer circumference. If it is.

The detection signal G on the left side by the succeeding beam includes the signal of the track n-1 on the inner circumference side as crosstalk, and the detection signal H on the right side is the recorded signal recorded immediately before by the main spot on the track n. The signal of the section is included as crosstalk. The preceding spot is track n and track n
Since it is located in the unrecorded portion of +1, the detection signals E and F by the preceding beam do not include the signal component of the recorded portion, but include only the modulation component.

The difference signal E−
By taking H and canceling out the modulation component, it is possible to generate a reproduction RF signal of the recorded portion recorded immediately before by the main spot. The difference signal E-H can be formed into a waveform by the comparator 42 in the same manner as in the first embodiment, and a reproduced signal can be generated.
3 or the signal processing circuit 44 can make an error determination.

The detection signal F may be used instead of the detection signal E. Further, a configuration may be employed in which the modulation component is removed by using only the detection signal H and switching the amplification degree of the amplifier as in the second embodiment.

[0040]

As described above, according to the present invention, during the data recording operation by the main light beam, the verify operation can be performed by reproducing the data by the rear sub light beam.
It has features such as the ability to perform a verify operation without lowering the data processing efficiency . In addition, the present invention
According to this, it is possible to obtain the reproduction data for verification by using the rear sub-light beam originally present in the three-beam type optical disk device, so that a verification pickup is provided in addition to the recording / reproduction pickup, or There is no need to provide an optical system for separating the verifying beam, and the structure of the three-beam optical disk device that performs the verifying operation can be simplified, and the device can be downsized and the cost can be reduced. Features such as
Further, according to the present invention, the auxiliary light beam before and after the main beam is provided.
While shifting the beam by half a track from the main light beam
Also, the preceding or succeeding sub-light beam is 2
Unrecorded track components can be calculated from the detection results
Extracts and records unrecorded data from the sub-light beam that follows the main light beam.
Removes modulation components by subtracting rack components
By reproducing the signal, the signal component can be easily
It has features such as being able to extract only

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an optical system of an optical pickup using a differential push-pull method.

FIG. 2 is an explanatory diagram of a circuit for generating a tracking error signal and a beam arrangement.

FIG. 3 is a configuration diagram of a verifying circuit according to a first embodiment of the present invention.

FIG. 4 is a configuration diagram of a verifying circuit according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram relating to a signal detection portion of a verifying circuit according to a third embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 12 laser light source 13 collimator lens 14 diffraction grating 15 beam splitter 16 objective lens 17 lens 21, 22, 23 optical detector 25 optical disk 31, 32, 33, 37 differential amplifier 34, 36 amplifier 35 adder 41 differential amplifier 42 comparator 43 comparison determination circuit 44 signal processing circuit 45 a delay circuit 51 inverting amplifier 46 inverting amplifier 47 operational amplifier 48 analog switches 61 differential amplifier S ₁ main spot S _2, S ₃ side spot R _2, R ₃ negative feedback resistor

Claims (1)

(57) [Claims] 1. A light beam emitted from one light source is separated into a main light beam and a sub light beam, the main light beam is irradiated onto an optical disk, and the main light beam is scanned with respect to a scanning direction of the light beam. Before and after the radial direction of the optical disc
Half track in opposite directions to the main light beam
And irradiating said secondary light beam, and the main light beam performs recording and reproduction of data, the optical disk device for generating a tracking error signal by using both of the secondary light beam or the main beam and the secondary light beam In the light reflected from the disk by the auxiliary light beam,
A part of the main light beam that overlaps the scanning track and the scanning track
And the part of the track adjacent to the track
The optical detector divided into two parts as described above, and the detection signal detected from each part of the optical detector.
That is, the sub light beam located behind the main light beam
The detection obtained from the part of the main light beam that
Out of the main light beam from the output signal
Of the sub-light beam that hangs over the unrecorded track
Data detection means for detecting data recorded on the optical disk by the main light beam by subtracting the detection signal from the main light beam, and error determination means for determining an error in the data detected by the data detection means. An optical disc device characterized by the above-mentioned.