JP2001034977A - Method and apparatus for detection of wobble signal, and information recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wobble-signal detecting method in which the influence of a crosstalk from the wobble of an adjacent track can be reduced even in an optical information recording medium having no prepit and in which a wob ble signal having a small change in an amplitude and a phase can be detected. SOLUTION: Not only a wobble signal component which is contained in the difference signal Mpp of a main beam MB but also difference signals S1rc S2rc of wobble signal components which are contained in signals of beams of reflected light of a first subbeam SB1 and a second subbeam SB2 are computed, and a wobble signal is detected. Thereby, a change in the amplitude and the phase of a wobble signal generated by a crosstalk from a wobble in an adjacent track can be suppressed, the lack of the wobble signal is prevented, and information on the rotation of an optical information recording medium can be detected precisely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a CD-R / RW
(Compmpact Disk-Recodable / Riwritable), DV
D (Digital Versatile or Video Disk)-R / R
The present invention relates to a wobble signal detection method for detecting a wobble signal of a wobbled track formed on an optical information recording medium such as W, a wobble signal detection device, and an information recording device.

[0002]

2. Description of the Related Art Generally, a recordable optical disk has grooves (tracks) formed concentrically or spirally for tracking control of a light beam. The target position can be controlled. In the unrecorded area, since absolute position information or medium rotation speed information is required, this track is formed in a waviness having a predetermined amplitude and a predetermined period (generally called “wobble”), and this wobble is detected. By doing so, the above information is obtained.

Since the detected wobble signal indicates the rotation information of the optical disk, it is also used for controlling the rotation of the spindle motor. However, wobbles also exist in adjacent tracks, and crosstalk (leakage of signals) from wobbles in adjacent tracks occurs in the detected wobble signal. Will occur.

Further, by generating a clock multiplied on the basis of the detected wobble signal, a clock can be generated accurately in response to a subtle change in the rotation speed of the optical disk. Has limitations. Therefore, in Japanese Patent Application Laid-Open No. Hei 10-293926, a clock generated based on a wobble detection signal using pre-pits which are present at a predetermined location in a shape different from a wobble and do not receive crosstalk from an adjacent track is used. I am trying to correct it. As a result, the accuracy and stability of the clock generated by only the wobble detection signal whose amplitude and phase change due to the influence of the wobble of the adjacent track are increased.

[0005]

However, prepits are signals that exist only in the format of DVD-R media. Other formats without pre-pits cannot be handled, and the above publication example still has a problem. In addition, if the track pitch is further reduced due to the future increase in density, crosstalk from adjacent wobbles also increases, and the change in amplitude and phase further increases.

According to Japanese Patent Application Laid-Open No. 7-31962, the influence of crosstalk between adjacent tracks is eliminated, and the recording capability of small pits is maintained.
Although the extraction capability of the wobble signal is improved, specifically, when a wobble signal is extracted from the push-pull signal (difference signal) of the main beam, an RF component (high-frequency component) is generated due to crosstalk. However, since the noise is superimposed on the extracted wobble signal without being cancelled, this RF component is devised so that it can be canceled, and the wobble signal component is increased to improve the detection capability. Absent.

Therefore, the present invention does not use pre-pits,
It is an object of the present invention to provide a wobble signal detection method and a wobble signal detection device capable of reducing the influence of crosstalk from wobbles of an adjacent track even in an optical information recording medium without prepits and capable of detecting a wobble signal with little change in amplitude and phase. Aim.

Another object of the present invention is to provide an information recording apparatus capable of generating an accurate recording clock signal by using a wobble signal detected accurately as described above.

[0009]

According to a first aspect of the present invention, there is provided a wobble signal detecting method for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands. A main beam scanning on a desired track, a first sub-beam scanning first on one area adjacent to the track, and a second sub-beam scanning on another area adjacent to the track. Using three beams including a sub beam, the reflected light of the main beam is divided at least into two in a track tangential direction to calculate a difference signal Mpp between the two beams.
The reflected lights of the first and second sub beams are respectively converted into signals S1rc,
S2rc, and calculates a difference signal between the wobble signal component included in the signal S1rc and the wobble signal component included in the signal S2rc. The wobble signal component included in the difference signal and the wobble included in the difference signal Mpp are calculated. The wobble signal is calculated from the signal component.

Therefore, the wobble signal is detected by calculating not only the wobble signal component contained in the difference signal of the main beam but also the difference signal of the wobble signal component contained in the reflected light signals of the first and second sub beams. Thereby, it is possible to suppress the amplitude and phase change of the wobble signal caused by the crosstalk from the wobble of the adjacent track,
Loss of the wobble signal can be prevented, and rotation information of the optical information recording medium can be accurately detected.

According to a second aspect of the present invention, in the wobble signal detection method according to the first aspect, an interval between the main beam and the first sub beam and an interval between the main beam and the second sub beam are wobbled. It is set to an integral multiple of half the period.

Accordingly, the conditions under which the invention described in claim 1 can be most effectively performed become clear, and can be used as a reference in creating a new wobble format.

A wobble signal detecting method according to a third aspect of the present invention is a wobble signal detecting method for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands. Using at least two beams of a main beam to be scanned and a sub-beam that scans first on one area adjacent to the track or a sub-beam that scans later on another area adjacent to the track; The reflected light of the beam is divided into at least two in the track tangential direction to calculate a difference signal Mpp between the two, and the reflected light of the sub-beam is converted into a signal Src, and the amplitude of a wobble signal component included in the signal Src is calculated. , Based on the amplitude of the wobble signal component, And so as to output the wobble signal by changing the width ratio.

Accordingly, the amplitude of the wobble signal component included in the reflected light signal of the sub beam, which is correlated with the change in the amplitude of the wobble signal included in the difference signal of the main beam, is detected, and the amplification of the wobble signal obtained from the main beam is performed. By changing the rate to a constant amplitude, it is possible to suppress the change in the amplitude and phase of the wobble signal caused by the crosstalk from the wobble of the adjacent track, prevent the wobble signal from being lost, and prevent the rotation information of the optical information recording medium from being lost. Can also be accurately detected.

A wobble signal detecting method according to a fourth aspect of the present invention is a wobble signal detecting method for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands. Using at least two beams of a main beam to be scanned and a sub-beam that scans ahead on one area adjacent to the track or a sub-beam that scans backward on the other area adjacent to the track; The reflected light of the beam is divided at least into two in the track tangential direction to calculate a difference signal Mpp between the two, and the reflected light of the sub beam is divided into at least two in the track tangential direction to calculate a difference signal Spp between the two. The amplitude of the wobble signal component included in the signal Spp is calculated, and the amplitude of the wobble signal component is calculated. And so as to output the wobble signal by changing the amplification factor of the wobble signal component included in Hazuki said difference signal Mpp.

Therefore, the amplitude of the wobble signal component included in the difference signal of the sub beam, which is correlated with the amplitude change of the wobble signal included in the difference signal of the main beam, is detected, and the amplification factor of the wobble signal obtained from the main beam is determined. By changing the amplitude to a constant amplitude, it is possible to suppress the change in the amplitude and phase of the wobble signal caused by the crosstalk from the wobble of the adjacent track, prevent the loss of the wobble signal, and accurately obtain the rotation information of the optical information recording medium. Can be detected.

A wobble signal detecting method according to a fifth aspect of the present invention is a wobble signal detecting method for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands. Using the main beam to be scanned, the reflected light of the main beam is divided into at least two in the track tangential direction to calculate a difference signal Mpp between the two, and the difference signal Mpp is calculated.
Is calculated, and based on the amplitude of the wobble signal component, the amplification factor of the wobble signal component included in the difference signal Mpp is changed to output the wobble signal.

Accordingly, since the amplitude change of the wobble signal component included in the difference signal of the main beam is detected and the amplitude of the wobble signal is changed to control the amplitude to be constant, the optical signal having only one main beam is provided. Also in the system, it is possible to suppress a change in amplitude and phase of a wobble signal caused by crosstalk from wobbles of an adjacent track, prevent loss of the wobble signal, and accurately detect rotation information of the optical information recording medium.

A wobble signal detecting device according to a sixth aspect of the present invention is a wobble signal detecting device for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands. A main beam to be scanned, a first sub-beam that scans ahead on one area adjacent to the track, and a second sub-beam that scans backward on the other area adjacent to the track.
Using an optical pickup that outputs a sub-beam, and reflecting the reflected light of the main beam at least two times in the track tangential direction.
An Mpp generation circuit that divides and calculates a difference signal Mpp between the two, an S1rc generation circuit that converts the reflected light of the first sub beam into a signal S1rc, and an S2rc generation circuit that converts the reflected light of the second sub beam into a signal S2rc A sub arithmetic circuit for calculating a difference signal between a wobble signal component included in the signal S1rc output from the S1rc generation circuit and a wobble signal component included in the signal S2rc output from the S2rc generation circuit; A wobble signal operation circuit that calculates a wobble signal from a wobble signal component included in the difference signal Mpp output from the generation circuit and a wobble signal component included in the difference signal output from the sub operation circuit.

Therefore, the wobble signal is detected by calculating not only the wobble signal component contained in the difference signal of the main beam but also the difference signal of the wobble signal component contained in the reflected light signals of the first and second sub beams. by doing,
It is possible to suppress a change in amplitude and phase of a wobble signal caused by crosstalk from a wobble of an adjacent track with a simple circuit configuration, prevent a loss of a wobble signal, and accurately detect rotation information of an optical information recording medium. it can.

According to a seventh aspect of the present invention, in the wobble signal detecting device according to the sixth aspect, an interval between the main beam and the first sub beam and an interval between the main beam and the second sub beam are wobbled. An optical pickup optical system set to an integral multiple of 1/2 of the period is used.

Accordingly, the conditions under which the invention described in claim 6 can be most effectively performed become clear, and can be used as a reference in creating a new wobble format.

The wobble signal detecting device according to the present invention is a wobble signal detecting device for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands. An optical pickup that outputs a main beam to be scanned and a sub-beam that scans ahead on one area adjacent to the track or a sub-beam that scans backward on the other area adjacent to the track, An Mpp generation circuit that divides the reflected light of the main beam into at least two in the track tangent direction to calculate a difference signal Mpp between the two, an Src generation circuit that converts the reflected light of the sub beam into a signal Src, and an output from the Src generation circuit. To calculate the amplitude of the wobble signal component included in the signal Src
rc amplitude calculation circuit and the Mpp based on the amplitude of the wobble signal component output from the Src amplitude calculation circuit.
An Mpp amplifier circuit that changes a gain of a wobble signal component included in the difference signal Mpp output from the generation circuit and outputs a wobble signal.

Therefore, the amplitude of the wobble signal component included in the reflected light signal of the sub beam, which is correlated with the amplitude change of the wobble signal included in the difference signal of the main beam, is detected, and the amplification of the wobble signal obtained from the main beam is performed. By changing the rate and controlling the amplitude to be constant, it is possible to suppress the change in the amplitude and phase of the wobble signal caused by the crosstalk from the wobble of the adjacent track with a simple circuit configuration, prevent the wobble signal from being lost, and prevent the optical information from being lost. The rotation information of the recording medium can also be accurately detected.

A wobble signal detecting device according to a ninth aspect of the present invention is a wobble signal detecting device for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands. An optical pickup that outputs a main beam to be scanned and a sub-beam that scans ahead on one area adjacent to the track or a sub-beam that scans backward on the other area adjacent to the track, An Mpp generation circuit that divides the reflected light of the main beam into at least two in the track tangential direction to calculate a difference signal Mpp between them, and an Mpp generating circuit that divides the reflected light of the sub beam into at least two in the track tangential direction to calculate the difference signal Spp between the two And a difference signal Spp output from the Spp generation circuit. And Spp amplitude calculation circuit for calculating the amplitude of the wobble signal component, the Mp based on the amplitude of the wobble signal component output from the Spp amplitude calculation circuit
an Mpp amplifier circuit that changes a gain of a wobble signal component included in the difference signal Mpp output from the p generation circuit and outputs a wobble signal.

Therefore, the amplitude of the wobble signal component included in the difference signal of the sub beam which is correlated with the amplitude change of the wobble signal included in the difference signal of the main beam is detected, and the amplification factor of the wobble signal obtained from the main beam is determined. By changing to a constant amplitude, the amplitude and phase change of the wobble signal caused by the crosstalk from the wobble of the adjacent track can be suppressed with a simple circuit configuration, the loss of the wobble signal can be prevented, and the optical information recording medium can be prevented. Can also be detected accurately.

A wobble signal detecting device according to a tenth aspect of the present invention is a wobble signal detecting device for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands. An optical pickup that outputs a main beam to be scanned is used, and the reflected light of the main beam is divided at least into two in a track tangential direction to calculate a difference signal Mpp between the two.
a pp generation circuit, an Mpp amplitude calculation circuit that calculates the amplitude of the wobble signal component included in the difference signal Mpp output from the Mpp generation circuit, and an Mpp amplitude calculation circuit that calculates the amplitude of the wobble signal component output from the Mpp amplitude calculation circuit. The difference signal Mpp output from the Mpp generation circuit based on
And an Mpp amplifying circuit that changes the amplification factor of the wobble signal component included in the signal and outputs a wobble signal.

Therefore, since the amplitude change of the wobble signal component included in the difference signal of the main beam is detected and the amplitude of the wobble signal is changed to control the amplitude to be constant, the optical signal having only one main beam is provided. In a system, the amplitude and phase change of the wobble signal caused by the crosstalk from the wobble of the adjacent track can be suppressed with a simple circuit configuration, preventing the loss of the wobble signal and accurately detecting the rotation information of the optical information recording medium. can do.

[0029] The information recording apparatus of the invention according to claim 11 is
An optical pickup including a recording light source that emits a light beam to an optical information recording medium, a wobble signal detection device according to any one of claims 6 to 10, and a wobble signal detected by the wobble signal detection device. A recording clock generation circuit for generating a recording clock signal for the recording light source using the recording clock signal.

Therefore, since the accurate wobble signal detected by the wobble signal detecting device according to any one of claims 6 to 10 is used for generating the recording clock signal, additional recording on the recorded optical information recording medium is performed. In the case where the recording position accuracy is required, such as when a part is rewritten, an accurate position and length can be recorded.

[0031]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG.

Prior to the description of the present embodiment, as a premise, a general method of wobble signal detection and its problems will be described.

In a recording optical disk, a DPP (Differential Push-Pull) tracking method for irradiating a medium with three light beams and controlling a beam position on a track composed of wobbled grooves and lands is generally used. Specifically, as shown in FIG. 2, the main beam MB that scans over a certain desired groove Gr2
And a region adjacent to the desired groove Gr2, for example, the first sub-beam SB1 that scans in advance on the outer circumferential land La2, and a region adjacent to the desired groove Gr2, for example, on the circumferential land La1. And a second sub-beam SB2 that scans after.

As an arithmetic circuit, the main beam M
A light detection signal Ma corresponding to the amount of reflected light of the outer peripheral half that is divided into two in the track tangential direction of the reflected light of B,
Of which, the light detection signal Mb corresponding to the amount of reflected light in the half of the peripheral side
A subtraction circuit 1 for calculating a difference signal Mpp from the first and second sub-beams SB1, and a light detection signal S1a corresponding to the light quantity of the outer half of the reflected light of the preceding first sub-beam SB1 divided into two in the track tangential direction. And a subtraction circuit 2 for calculating a difference signal S1pp from a light detection signal S1b corresponding to the amount of the reflected light of the half of the peripheral side, and of the reflected light of the succeeding second sub-beam SB2, A light detection signal S2a corresponding to the amount of reflected light of the divided outer peripheral half;
It has a subtraction circuit 3 for calculating a difference signal S2pp from the light detection signal S2b corresponding to the amount of reflected light of the half of the peripheral side, and a subtraction circuit 4 for subtracting the sum of these difference signals S1pp and S2pp from the difference signal Mpp.

The tracking error (T
E) The signal is extracted and used to control the main beam MB on the target track (desired track).
This tracking error signal generation method is called a DPP method, and is used for tracking on a recording medium. Generally, the wobble signal WBL is the main beam M
It is extracted from the B difference signal Mpp.

Here, in order to generate a wobble (WBL) signal, in a medium, a groove and a land are:
As shown in FIG. 3, it is wobbled and formed. Some wobbles are formed such that the fundamental frequency of the wobble signal is constant when the number of rotations of the medium is constant, but generally, the linear velocity of the medium (moving speed at a certain point) is generally constant. It is formed so that the fundamental frequency is constant when it is constant. For example, CD-R / RW
In the case of, it is formed as such. As described above, when the wobble signal has a constant linear velocity as described above, the radial position is different for each track, and the length of one round of the track is different (2π × track pitch becomes longer each time the track moves to the outer circumference side). The phase of the wobble signal of the groove Gr2 and the phase of the wobble signal of the groove Gr1 or Gr3 in FIG. 3 are different. Depending on the location, there may be a match.
In the case where the wobble signal of the outer track is in phase (phase difference 0 °) with the groove Gr2 as the center (FIG. 3)
(A)) and a case where the phases are completely opposite (a phase difference of 180 °) (FIG. 3 (b)). If the integral multiple of the wobble period is substantially equal to the difference between the lengths of the tracks (2π × track pitch), the phase difference of the wobble signal between adjacent tracks in a certain angular azimuth on the medium is fixed. In the angular azimuth, they are in phase, and in another angular azimuth, they are out of phase.

The physical media shape is as described above, but the detection signal is shown in the lower half of FIG. In the detection signal, the wobble signal (not shown) of the adjacent track causes leakage crosstalk, and a signal different from that in the case where there is a single track (although it is not possible) is detected. Looking at the difference signal Mpp, which is a general wobble signal, the amplitude greatly changes due to the influence of the wobble of the adjacent track. In a place where the wobble signal component obtained from the groove Gr2 and the wobble signal component of the adjacent track (land) are in phase (phase shift is 0 °) (FIG. 3).
(A)), the amplitude of the wobble signal obtained from the constructive difference signal Mpp increases. Conversely, the wobble signal component obtained from the groove Gr2 and the wobble signal component of the adjacent track (land) are out of phase (phase shift 18).
0 °) (FIG. 3B), the amplitude of the wobble signal obtained from each of the weakening differential signals Mpp becomes small.

FIG. 4 is a waveform diagram showing this state macroscopically. When a wobble signal is detected while the medium is rotating, a sine wave-shaped wobble signal is detected, but its amplitude fluctuates at a period slower than the wobble basic period due to the crosstalk of the wobble signals of adjacent tracks. In the case of an optical system in which the width of a light beam in a track tangential direction is narrow and made elliptical in order to increase the recording / reproducing resolution of recording data (pits), crosstalk between adjacent wobbles is large and amplitude fluctuations are extremely large. It has been confirmed that the amplitude of the wobble signal fluctuates until it is lost depending on the media and the optical system.

The fact that the amplitude of the wobble signal fluctuates until it is lost clearly poses a problem, but the problem of even the fluctuation of the wobble amplitude will be described with reference to a signal waveform diagram shown in FIG. If the amplitude of the wobble signal is constant, the intervals across a certain reference level are equal. However, in the portion where the amplitude fluctuates, the time to cross the reference level is shifted as shown in FIG. It can be seen that in the direction in which the amplitude decreases, the timing is later than the timing of crossing the reference level of an accurate signal without crosstalk, and conversely in the direction in which the amplitude increases. This is "phase shift". Even though the medium is rotating at a constant linear velocity, a signal different from the actual medium rotation information is detected due to crosstalk from wobbles of adjacent tracks.

If the wobbling width of the track is increased, the wobble signal increases, but the crosstalk also increases. Also,
Increasing the distance between tracks reduces crosstalk, but increases the track pitch and reduces the recording capacity. Even so, if the track interval and wobbling width are optimized for the wobble signal, the recording data existing on the track (a delicate signal having a higher frequency range and a smaller signal amplitude than the wobble signal)
The recording / reproducing condition of the wobble signal is deteriorated, and it is difficult to optimize the track shape for the wobble signal. As described above, the fluctuation in the amplitude of the wobble signal is a problem that is difficult to be relieved.

The present embodiment based on such a premise will be described. Also in the present embodiment, as described above, the general DPP method using three beams is used.

As shown in FIG. 1, the circuit configuration of the wobble signal detecting device according to the present embodiment
Of the reflected light, the light detection signal Ma corresponding to the amount of reflected light of the outer peripheral half divided into two in the track tangential direction, and the light detection signal Ma corresponding to the amount of reflected light of the peripheral half of the divided light halved in the track tangential direction. A subtraction circuit 10 as an Mpp generation circuit for calculating a difference signal Mpp from the detected light detection signal Mb, and a reflected light of a half of an outer peripheral half of the reflected light of the preceding first sub-beam SB1 divided into two in the track tangential direction. The light detection signal S1a corresponding to the light amount and the two divided in the track tangential direction
An adder circuit 11 as an S1rc generation circuit for obtaining a sum signal S1rc with a light detection signal S1b corresponding to the amount of reflected light of the half of the circumferential side, and a track tangential direction of reflected light of a succeeding second sub-beam The sum signal S2rc of a light detection signal S2a corresponding to the light quantity of the reflected light of the outer peripheral half divided into two, and a light detection signal S2b corresponding to the light quantity of the reflected light of the peripheral half of the two divided in the track tangential direction. S2 to get
an addition circuit 12 as an rc generation circuit, and a sum signal S1rc
And a wobble signal for further adding and subtracting the output of the sub-operation circuit and the wobble signal component included in the difference signal Mpp to calculate the difference between the wobble signal component included in the sum signal S2rc and the wobble signal component included in the sum signal S2rc. And an arithmetic circuit 13 having the function of the arithmetic circuit.
This calculation will be described later. In the present embodiment, the wobble signal WBL is extracted from the output of the arithmetic circuit 13.

In this embodiment, the optical system for DPP has been described as an example, and it is assumed that the light receiving element of the sub-beam SB is divided. However, it is needless to say that a light receiving element that is not divided may be used. Adder circuits 11 and 12 of both
Is unnecessary, and it is sufficient that the signals S1rc and S2rc can be extracted from the reflected light of the sub beams SB1 and SB2, and the circuits for that purpose become the generation circuits. Further, there may be a case where the light receiving element has more divisions for the calculation of the focus and the like, but a combination of the divided light receiving elements which can detect the wobble signal component may be used.

The signal level of such a configuration will be described with reference to FIG. First, the amplitude of the wobble signal detected from the difference signal Mpp increases when the wobbles of the adjacent tracks are in phase (phase difference 0 °) and decreases when the wobbles of the adjacent tracks are opposite phase (phase difference 180 °) as described above. It is. Focusing on S1rc and S2rc as other signals, there is no signal component when in phase (FIG. 3A), and a signal component having the same cycle as the difference signal Mpp is detected when out of phase (FIG. 3B). is made of. This is due to the shape of the land scanned by the sub-beam SB. Since the wobble wobbles with the width of the groove in which the recording data exists, the land shape sandwiched between the outer grooves As a result, the width changes. At the time of the in-phase, since the width of the land is almost constant, the signals S1rc and S2r
c (usually called a "radial contrast signal") has no (small) amplitude. However, when the width changes in the opposite phase, an amplitude corresponding to the width appears. This phenomenon is particularly remarkable when the groove width is close to half the track pitch. Since the radial contrast signal of the sub beam SB has a phase opposite to that of S1rc and S2rc, the subtraction increases the amplitude, which is convenient. Of course, there is an effect even with only one of S1rc and S2rc. A good wobble signal W is obtained by adding or subtracting a wobble signal having the same frequency component (wobble frequency) as the wobble signal detected from the difference signal Mpp so as to increase the amplitude.
BL is obtained.

Here, the interval between the main beam MB and the first and second sub beams SB1 and SB2 will be considered. FIG.
Is most effective when the intervals between the main beam MB and the first and second sub-beams SB1 and SB2 are each an integral multiple of half the wobble period. Since the polarity of the difference signal between the signals S1rc and S2rc obtained from the first and second sub-beams SB1 and SB2 is different between the odd number times and the even number times, the calculation method with the sum signal has the same phase. Must be added or subtracted from Incidentally, when the above-mentioned interval is の of the wobble period (Tw), the state shown in FIG. 2 is obtained. Therefore, the final operation expression is Mpp + (S1rc−S2
rc). Completely main beam MB and sub beam S
The effect is obtained even if the interval between B1 and SB2 is not half of the wobble period, but the effect is lost if the interval deviates greatly. This state is shown in FIG. The most shifted state is the case of 1/4 of the wobble cycle. At this time, the signals S1rc,
S2rc has the same phase, the difference signal becomes 0, and the phase with the difference signal Mpp is also different.

A second embodiment of the present invention will be described with reference to FIG. Also in the case of the present embodiment, the optical system and Mpp
The detection circuit is the same as that of the first embodiment, and the same parts as those shown in the first embodiment are denoted by the same reference numerals and the description is omitted.

As described with reference to FIG. 3, the amplitude of the wobble signal WBL obtained from the difference signal Mpp changes according to the wobble phase of the adjacent track. Therefore, the wobble signal WB obtained from the difference signal Mpp by detecting the amplitude change
L is corrected.

As can be seen from FIG. 3, the signal representing the amplitude of the wobble signal WBL obtained from the difference signal Mpp is the amplitude of the wobble signal component of the difference signal S1pp of the first sub-beam SB1 and the difference signal S2pp of the second sub-beam SB2. The amplitude of the wobble signal component is equal to the difference signal Mpp.
, And the amplitude of the wobble signal component of the signal S1rc and the amplitude of the wobble signal component of the signal S2rc are inversely proportional. Therefore, in the present embodiment, at least one of these signals is detected by the amplitude calculation circuit 14, and the wobble signal component of the difference signal Mpp is proportionally or inversely proportional to the detected signal by the Mpp amplification circuit 15. Amplify.

More specifically, an Src generation circuit 16 (corresponding to the addition circuit 11 or 12) for converting the reflected light of the sub beam SB (SB1 or SB2) into a signal Src, and this Src
An amplitude calculation circuit 14 as a Src amplitude calculation circuit for calculating the amplitude of the wobble signal component included in the signal Src output from the generation circuit 16, and Mpp generation based on the amplitude of the wobble signal component output from the amplitude calculation circuit 14. It is configured as an Mpp amplifier circuit 15 that changes the amplification factor of the wobble signal component included in the differential signal Mpp output from the circuit 10 and outputs the wobble signal WBL.

Alternatively, the sub beam SB (SB1 or SB1
The Spp generation circuit 16 that divides the reflected light of 2) at least into two in the track tangential direction and calculates a difference signal Spp between the two.
(Corresponding to the subtraction circuit 2 or 3) and the Spp generation circuit 1
6, an amplitude calculation circuit 14 as a Spp amplitude calculation circuit for calculating the amplitude of the wobble signal component included in the difference signal Spp, and Mpp generation based on the amplitude of the wobble signal component output from the amplitude calculation circuit 14. Circuit 1
Mp that changes the amplification factor of the wobble signal component included in the difference signal Mpp output from 0 and outputs a wobble signal
It is configured as a p-amplifier circuit 15.

Alternatively, when only the main beam MB is used, the difference signal Mp output from the Mpp generation circuit 10 is used.
Mpp for calculating the amplitude of the wobble signal component included in p
An amplitude operation circuit 14 as an amplitude operation circuit, and a difference signal Mpp output from the Mpp generation circuit 10 based on the amplitude of the wobble signal component output from the amplitude operation circuit 14
Is configured as an Mpp amplifying circuit 15 that changes the amplification factor of the wobble signal component included in and outputs a wobble signal.

In any case, the ideal amplitude of the wobble signal WBL as shown in FIG. 4 is obtained, and the phase shift due to the amplitude fluctuation as shown in FIG. 5 can be suppressed.

A third embodiment of the present invention will be described with reference to FIG. In this embodiment, a wobble signal detection circuit 21 as a wobble signal detection device having a configuration as in the first and second embodiments is applied to an information recording device. An optical pickup (PU) 24 is provided, which irradiates a laser beam onto an optical information recording medium 23 driven by a spindle motor 22 to receive a reflected light from the optical information recording medium 23 and performs a predetermined detection operation. . A semiconductor laser (not shown) functioning as a recording light source is provided in the optical pickup 24. An LD driver 25 for driving the semiconductor laser (LD) is provided. An encoder circuit 26 is connected to the LD driver 25. Further, a servo signal generation circuit 27 for tracking / focusing is provided based on a detection signal from the optical pickup 24, and the servo signal generation circuit 27 is connected to a servo processing circuit 28. A spindle motor control circuit 29 is connected to the spindle motor 22. further,
The wobble signal detection circuit 21 described above is
4 is connected to the detection output system. The wobble signal detection circuit 21 is connected to a recording clock generation circuit 30 and a spindle motor control circuit 29, and the recording clock generation circuit 30 is connected to an encoder circuit 26 and a spindle motor control circuit 29.

In such a configuration, the LD driver 2
The beam emitted from the semiconductor laser driven by 5 is focused and irradiated on the optical information recording medium 23 by the optical pickup 24. The position control of the focal point of the beam is performed by calculating a position information signal obtained from the optical pickup 24 by a servo signal generation circuit 27, and based on this output, a servo processing circuit 28.
By driving the objective lens actuator in the optical pickup 24. By scanning a desired track with a light beam, a wobble signal can be extracted by the wobble signal detection circuit 21 having the above-described configuration using a signal output from the optical pickup 24.
An encoder that generates a recording clock accurately following the rotation of the optical information recording medium 23 by the recording clock generation circuit 30 based on the wobble signal and performs modulation for recording the recording data on the optical information recording medium 23. The circuit 26 drives the LD driver 25 based on the recording clock to form accurate recording pits on the optical information recording medium 23. Although the spindle motor control circuit 29 basically controls the rotation of the spindle motor 22 using a fixed reference clock or wobble signal, the output of the recording clock generation circuit 30 may be used to increase the control accuracy. .

[0055]

According to the wobble signal detection method of the present invention, not only the wobble signal component contained in the difference signal of the main beam, but also the wobble signal contained in the reflected light signal of the first and second sub beams. Since the wobble signal is detected by performing the calculation including the difference signal of the components, the amplitude and phase change of the wobble signal caused by the crosstalk from the wobble of the adjacent track can be suppressed, and the lack of the wobble signal can be suppressed. Thus, the rotation information of the optical information recording medium can be accurately detected.

According to the second aspect of the present invention, the conditions under which the wobble signal detecting method according to the first aspect can be performed most effectively become clear, and can be used as a reference in creating a new wobble format.

According to the wobble signal detection method of the third aspect of the present invention, the amplitude of the wobble signal component included in the reflected light signal of the sub beam correlated with the change in the amplitude of the wobble signal included in the difference signal of the main beam is determined. By detecting and controlling the amplitude of the wobble signal obtained from the main beam to a constant amplitude, the amplitude and phase change of the wobble signal caused by the crosstalk from the wobble of the adjacent track can be suppressed. Loss of a signal can be prevented, and rotation information of the optical information recording medium can be accurately detected.

According to the wobble signal detection method of the present invention, the amplitude of the wobble signal component included in the difference signal of the sub beam correlated with the amplitude change of the wobble signal included in the difference signal of the main beam is detected. By changing the amplification factor of the wobble signal obtained from the main beam and controlling it to a constant amplitude, it is possible to suppress the change in the amplitude and phase of the wobble signal caused by the crosstalk from the wobble of the adjacent track, and Prevent missing,
The rotation information of the optical information recording medium can also be accurately detected.

According to the wobble signal detection method of the present invention, the amplitude change of the wobble signal component included in the difference signal of the main beam is detected, and the amplitude of the wobble signal is changed to be controlled to a constant amplitude. Therefore, even in an optical system having only one main beam, changes in the amplitude and phase of a wobble signal caused by crosstalk from wobbles in an adjacent track can be suppressed, loss of the wobble signal can be prevented, and optical information recording can be performed. The rotation information of the medium can also be accurately detected.

According to the wobble signal detecting device of the present invention, not only the wobble signal component contained in the difference signal of the main beam but also the wobble signal component contained in the reflected light signals of the first and second sub beams are provided. Since the wobble signal is detected by calculating including the difference signal,
It is possible to suppress a change in amplitude and phase of a wobble signal caused by crosstalk from a wobble of an adjacent track with a simple circuit configuration, prevent a loss of a wobble signal, and accurately detect rotation information of an optical information recording medium. it can.

According to the seventh aspect of the present invention, the conditions under which the wobble signal detecting device according to the sixth aspect can be most effectively clarified, and can be used as a reference in creating a new wobble format.

According to the wobble signal detecting device of the present invention, the amplitude of the wobble signal component included in the reflected light signal of the sub-beam correlated with the amplitude change of the wobble signal included in the difference signal of the main beam. By detecting and changing the amplification factor of the wobble signal obtained from the main beam to control the amplitude to a constant value, a change in the amplitude and phase of the wobble signal caused by crosstalk from the wobble of the adjacent track can be suppressed with a simple circuit configuration. As a result, loss of the wobble signal can be prevented, and the rotation information of the optical information recording medium can be accurately detected.

According to the wobble signal detecting apparatus of the ninth aspect, the amplitude of the wobble signal component included in the difference signal of the sub beam correlated with the amplitude change of the wobble signal included in the difference signal of the main beam is detected. By changing the amplification factor of the wobble signal obtained from the main beam and controlling the amplitude to be constant, it is possible to suppress the change in the amplitude and phase of the wobble signal caused by the crosstalk from the wobble of the adjacent track with a simple circuit configuration. Thus, the wobble signal can be prevented from being lost, and the rotation information of the optical information recording medium can be accurately detected.

According to the wobble signal detecting device of the tenth aspect, a change in the amplitude of the wobble signal component included in the difference signal of the main beam is detected, and the amplitude of the wobble signal is changed to control the amplitude to be constant. Therefore, even in an optical system having only one main beam, changes in the amplitude and phase of a wobble signal caused by crosstalk from wobbles in an adjacent track can be suppressed with a simple circuit configuration, and loss of the wobble signal can be prevented. Thus, the rotation information of the optical information recording medium can be accurately detected.

According to the information recording apparatus of the present invention, it is possible to generate a recording clock signal.
Since an accurate wobble signal detected by the wobble signal detection device according to any one of the above is used, additional recording on a recorded optical information recording medium, rewriting of a part, and the like, when recording position accuracy is required, The exact position and length can be recorded.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a principle of wobble signal detection according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing the principle of general tracking signal detection.

FIG. 3 is a waveform diagram showing a case where a wobble phase difference is 0 ° and a case where it is 180 °.

FIG. 4 is an enlarged waveform diagram showing a part thereof in a macro manner.

FIG. 5 is a waveform diagram for explaining an adverse effect due to a phase shift of a wobble signal.

FIG. 6 is a waveform diagram showing a case where a wobble phase difference is 0 ° and a case where it is 180 °.

FIG. 7 is a schematic diagram illustrating the principle of wobble signal detection according to the second embodiment of the present invention.

FIG. 8 is a block diagram illustrating a configuration example of an information recording device according to a third embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 10 Mpp generation circuit 11 S1rc generation circuit 12 S2rc generation circuit 13 Sub calculation circuit & wobble signal calculation circuit 14 Src amplitude calculation circuit, Spp amplitude calculation circuit,
Mpp amplitude calculation circuit 15 Mpp amplification circuit 16 Src generation circuit, Spp generation circuit 21 Wobble signal detection device 24 Optical pickup 30 Recording clock generation circuit MB Main beam SB1 First sub beam SB2 Second sub beam

Claims (11)

[Claims] 1. A wobble signal detection method for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands, comprising: a main beam for scanning a desired track; The reflected light of the main beam is tangent to the track using three beams, a first sub-beam that scans ahead on one area and a second sub-beam that scans backward on the other area adjacent to the track. And at least divide the reflected light of the first and second sub-beams into a signal S1r.
c, S2rc, and calculates a difference signal between the wobble signal component included in the signal S1rc and the wobble signal component included in the signal S2rc, and includes the wobble signal component included in the difference signal and the difference signal included in the difference signal Mpp. A wobble signal detection method for calculating a wobble signal from a wobble signal component to be calculated. 2. An interval between the main beam and the first sub beam and an interval between the main beam and the second sub beam are set to an integral multiple of 1/2 of a wobble period. Wobble signal detection method. 3. A wobble signal detecting method for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands, comprising: a main beam for scanning a desired track; Using at least two beams, a sub-beam that scans first on one area or a sub-beam that scans backward on the other area adjacent to the track, and reflects reflected light of the main beam in at least two directions in a track tangential direction. The signal is divided and the difference signal Mpp between the two is calculated, the reflected light of the sub beam is converted into a signal Src, the amplitude of a wobble signal component included in the signal Src is calculated, and the difference is calculated based on the amplitude of the wobble signal component. The wobble signal is output by changing the amplification factor of the wobble signal component included in the signal Mpp. The wobble signal detection method in. 4. A wobble signal detection method for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands, comprising: a main beam for scanning a desired track; Using at least two beams, a sub-beam that scans first on one area or a sub-beam that scans backward on the other area adjacent to the track, and reflects reflected light of the main beam in at least two directions in a track tangential direction. In addition to calculating the difference signal Mpp between the two, the reflected light of the sub-beam is divided into at least two in the track tangential direction to calculate the difference signal Spp between the two, and the amplitude of the wobble signal component included in the difference signal Spp is calculated. The wobble included in the difference signal Mpp is calculated based on the amplitude of the wobble signal component. Wobble signal detection method so as to output the wobble signal by changing the amplification factor of the No. components. 5. A wobble signal detection method for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands, using a main beam for scanning a desired track. The reflected light is divided into at least two in the track tangential direction to calculate a difference signal Mpp between the two, calculate the amplitude of a wobble signal component included in the difference signal Mpp, and calculate the difference signal Mpp based on the amplitude of the wobble signal component. A wobble signal detection method in which the amplification factor of the wobble signal component included in the wobble signal is changed to output the wobble signal. 6. A wobble signal detecting device for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands, comprising: a main beam for scanning a desired track; Using an optical pickup that outputs a first sub-beam that scans ahead on one area and a second sub-beam that scans backward on the other area adjacent to the track; Mpp for calculating a difference signal Mpp between the two by dividing at least two in the track tangential direction
A generation circuit; an S1rc generation circuit that converts the reflected light of the first sub-beam into a signal S1rc; an S2rc generation circuit that converts the reflection light of the second sub-beam into a signal S2rc; and the signal output from the S1rc generation circuit. S1rc
And a sub-arithmetic circuit for calculating a difference signal between the wobble signal component included in the signal S2rc and the wobble signal component included in the signal S2rc output from the S2rc generation circuit, and the difference signal Mpp output from the Mpp generation circuit
And a wobble signal operation circuit that calculates a wobble signal from the wobble signal component included in the differential operation signal and the wobble signal component included in the difference signal output from the sub operation circuit. 7. An optical pickup optical system in which an interval between the main beam and the first sub-beam and an interval between the main beam and the second sub-beam are set to an integral multiple of ウ ォ of a wobble period. The wobble signal detection device according to claim 6, wherein the wobble signal detection device is used. 8. A wobble signal detecting device for detecting a wobble signal by scanning a light beam on a track composed of wobbled grooves and lands, comprising: a main beam for scanning a desired track; Using an optical pickup that outputs a sub-beam that scans ahead on one area or a sub-beam that scans backward on the other area adjacent to the track, and reflects the reflected light of the main beam in the track tangential direction. Mpp for calculating a difference signal Mpp between at least two parts
A generating circuit, and Src for converting the reflected light of the sub beam into a signal Src
A Src amplitude calculation circuit for calculating the amplitude of a wobble signal component included in the signal Src output from the Src generation circuit; and a Src amplitude calculation circuit based on the amplitude of the wobble signal component output from the Src amplitude calculation circuit. A wobble signal detection device comprising: an Mpp amplification circuit that changes a gain of a wobble signal component included in the difference signal Mpp output from an Mpp generation circuit and outputs a wobble signal. 9. A wobble signal detection device for scanning a track composed of wobbled grooves and lands with a light beam and detecting a wobble signal, comprising: a main beam for scanning a desired track; and a wobble signal adjacent to the track. Using an optical pickup that outputs a sub-beam that scans ahead on one area or a sub-beam that scans backward on the other area adjacent to the track, and reflects the reflected light of the main beam at least in the track tangential direction. Mpp that divides into two and calculates the difference signal Mpp between them
A Spp generation circuit that divides the reflected light of the sub-beam into at least two in a track tangential direction to calculate a difference signal Spp between the two, and the difference signal Spp output from the Spp generation circuit
And a wobble signal included in the difference signal Mpp output from the Mpp generation circuit based on the amplitude of the wobble signal component output from the Spp amplitude calculation circuit. A wobble signal detection device comprising: an Mpp amplifier circuit that changes a gain of a signal component and outputs a wobble signal. 10. A wobble signal detecting device for scanning a track composed of wobbled grooves and lands with a light beam and detecting a wobble signal, using an optical pickup for outputting a main beam for scanning a desired track. Mpp for calculating the difference signal Mpp between the two by dividing the reflected light of the main beam into at least two in the track tangential direction.
And a difference circuit Mpp output from the Mpp generation circuit.
An Mpp amplitude calculation circuit for calculating the amplitude of the wobble signal component included in the MPP signal; and a wobble included in the difference signal Mpp output from the Mpp generation circuit based on the amplitude of the wobble signal component output from the Mpp amplitude calculation circuit. A wobble signal detection device comprising: an Mpp amplifier circuit that changes a gain of a signal component and outputs a wobble signal. 11. An optical pickup including a recording light source for emitting a light beam to an optical information recording medium, a wobble signal detection device according to claim 6, and detection by the wobble signal detection device. A recording clock generation circuit for generating a recording clock signal for the recording light source using the obtained wobble signal.