JP2002056532A - Recording and/or reproducing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and surely detect land prepits from an optical disk whereon the land prepits of the address information, etc., are arranged on the land while a recording track is wobbled with the prescribed frequency independently of the time of recording or reproducing operation. SOLUTION: Out of a (A+B) signal and a (C+D) signal for detecting a radial push-pull signal, the multiplying process is carried out for the (A+B) signal by a specific coefficient k. This specific coefficient k is suitably made variable in accordance with an error rate when the land prepit is decoded, the lens shift amount of an objective lens of an optical pickup 2, and a level of the land prepit signal or wobbling signal with respect to a signal level of a sum signal. Thus, the land prepits on the optical disk are accurately and surely detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a DVD-R
The present invention relates to a recording and / or reproducing apparatus and method suitable for being applied to a DVD reproducing apparatus, a DVD recording apparatus, a DVD recording / reproducing apparatus, etc., for recording / reproducing on / from an optical disk such as a DVD-RW.

[0002]

2. Description of the Related Art Generally, recordable optical recording media include:
In order to enable recording of desired information, address information and the like are recorded in advance in the form of pre-pits, and a recording track wobbled at a predetermined frequency is used to generate a clock signal used for a recording / reproducing operation. Is provided.

As such an optical recording medium, for example, C
DVD-R (Digital Versatil) capable of recording about 7 times the information of D (Compact Disc)
eDisc-Recordable) is known.
The DVD-R has a concave pre-groove which is an area where information to be originally recorded such as video data and audio data is recorded as recording pits, and an address on a convex land which is an area between the pre-grooves. Information and the like are recorded in advance in the form of land pre-pits (LPP).

A land pre-pit (LPP) on a land
Are recorded on a straight line perpendicular to the tangential direction of the pregroove so as not to be adjacent to the pregroove. The pre-groove is provided so as to slightly wobble at a predetermined frequency in a radial direction of the optical disk at a frequency based on a reference clock used for rotation control of the DVD-R.

When such a DVD-R rotation control is performed, a wobbling frequency is detected from a reproduction output of a wobbled pre-groove (hereinafter, referred to as a wobbling groove), and the detected wobbling frequency is used as a reference clock. Feedback control is performed to match the frequency.

The land pre-pit (LPP) divides the reflected light of the light beam (laser beam) from the semiconductor laser applied to the wobbling groove into at least two by a dividing line optically parallel to the tangential direction of the wobbling groove. A difference signal is obtained by calculating a difference in a direction perpendicular to the wobbling groove of an output signal from each area (divided individual area) of the light receiving element, and obtaining a difference signal. A binary signal binarized by comparison with a predetermined threshold is detected.

When the disk-shaped recording medium is an optical disk, the above-mentioned division line forms a divided region of the light receiving element along the radial direction (radial direction) of the optical disk. Called the signal.

As described above, the land pre-pit (LPP) can be detected by the binarized signal obtained by comparing the radial push-pull signal (difference signal) with a predetermined threshold value as described above. This is because (LPP) is formed such that it does not exist on an adjacent land on a straight line perpendicular to the tangential direction of the wobbling groove.

That is, when a light beam is applied to one wobbling groove, the reflected light from the lands on both sides does not include the reflection component of the land prepit (LPP) at the same time (the light reflected from one of the lands). Since the LPP component exists only in the reflected light), only the reflected light component of the land prepit (LPP) is extracted by performing the above-described difference calculation.

However, normally, a binary signal obtained by comparing one of the bipolar components (for example, the positive component) by a difference operation with a predetermined threshold value is used as a land pre-pit signal (LPP signal).

[0011]

By the way, DVD-R
In optical discs such as DVDs and DVD-RWs, land pre-pits (LPP) are binarized by comparing a radial push-pull signal (difference signal) with a predetermined threshold and detected based on the binarized signal. , The amplitude ratio of the two input signals for calculating the radial push-pull signal (difference signal) is adjusted to be equal. According to this method, the laser power during recording in the land pre-pit (LPP) The modulation component becomes noise, or
In the reproduction mode, there is a problem that land pre-pits (LPP) are erroneously detected due to the influence of recording pits. Also, if a lens shift occurs due to the objective lens in the recording / reproducing mode of the optical disc, the balance of the radial push-pull signal is lost.
There is a problem that P) is erroneously detected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a recording and / or reproducing apparatus and method capable of accurately extracting a land pre-pit signal (LPP signal) with a simple configuration. The purpose is to provide.

[0013]

According to a first aspect of the present invention, there is provided a recording and / or reproducing apparatus according to the present invention, wherein a wobbling groove which is wobbled at a predetermined frequency and serves as a recording track of an information signal, has a predetermined wobbling period interval. A recording and / or reproducing operation for recording and / or reproducing the information signal on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land prepits in a spiral or concentric manner. In the device,
When a light beam is applied to the disc-shaped recording medium, first and second light-receiving areas at which the reflected light from the disc-shaped recording medium is at least equally divided along the recording tracks of the disc-shaped recording medium At the first and second
Coefficient multiplying means for multiplying one of the light receiving outputs of the light receiving areas by a predetermined coefficient and outputting the result, and the other light receiving output of the light receiving outputs of the first and second light receiving areas A push-pull signal generating means for outputting a difference obtained by subtracting an output of a result of the multiplication processing by the coefficient multiplying means as a radial push-pull signal; and a land pre-pit signal corresponding to a land pre-pit of the land from the radial push-pull signal. And a land pre-pit signal amplitude detecting means for detecting and outputting the amplitude of the land pre-pit signal, and extracting the wobbling signal of the wobbling groove from the radial push-pull signal, and calculating the amplitude of the wobbling signal. Wobbling signal amplitude detection means for detecting and outputting, and the amplitude of the land pre-pit signal, or Coefficient setting means for setting the value of the predetermined coefficient to a value larger than 1.0 and within a range in which the land pre-pit signal can be detected, based on the amplitude of the land pre-pit signal and the amplitude of the wobbling signal; Is provided.

According to a second aspect of the present invention, there is provided a recording and / or reproducing apparatus according to the present invention, wherein a wobbling groove wobbled at a predetermined frequency and serves as a recording track of an information signal, and at least address information at a predetermined wobbling cycle interval. In a recording and / or reproducing apparatus for recording and / or reproducing the information signal on a disk-shaped recording medium in which lands pre-recorded as land prepits are alternately formed spirally or concentrically, When a beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium.
A coefficient multiplying means for receiving light in a second light receiving region, multiplying one of the light receiving outputs of the first and second light receiving regions by a predetermined coefficient, and outputting the result; A push-pull signal generating means for outputting, as a radial push-pull signal, a difference obtained by subtracting an output of a result of the multiplication processing by the coefficient multiplying means from the other light-receiving output of the second light-receiving area; A land pre-pit signal corresponding to a land pre-pit of the land is extracted from the signal, a land pre-pit signal amplitude detecting means for detecting and outputting the amplitude of the land pre-pit signal, and the wobbling from the radial push-pull signal. Wobbling signal amplitude detecting means for extracting a wobbling signal of the groove, detecting and outputting the amplitude of the wobbling signal, Sum signal generating means for summing the respective light receiving outputs of the first and second light receiving regions and outputting a sum signal, and dividing the amplitude of the land pre-pit signal by the sum signal to thereby normalize the signal. Normalized land pre-pit signal amplitude generating means for outputting the amplitude of the land pre-pit signal, and normalization for outputting the amplitude of the normalized wobbling signal by dividing the amplitude of the wobbling signal by the sum signal. Wobbling signal amplitude generation means, the predetermined coefficient based on the amplitude of the normalized land pre-pit signal, or the amplitude of the normalized land pre-pit signal and the amplitude of the normalized wobbling signal. Is set to a value greater than 1.0 and within a range in which the land pre-pit signal can be detected.

According to a third aspect of the present invention, there is provided a recording and / or reproducing apparatus according to the present invention, wherein a wobbling groove wobbled at a predetermined frequency and serves as a recording track of an information signal, and at least address information at a predetermined wobbling cycle interval. In a recording and / or reproducing apparatus for recording and / or reproducing the information signal on a disk-shaped recording medium in which lands pre-recorded as land prepits are alternately formed spirally or concentrically, When a beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium.
A coefficient multiplying means for receiving light in a second light receiving region, multiplying one of the light receiving outputs of the first and second light receiving regions by a predetermined coefficient, and outputting the result; A push-pull signal generating means for outputting, as a radial push-pull signal, a difference obtained by subtracting an output of a result of the multiplication processing by the coefficient multiplying means from the other light-receiving output of the second light-receiving area; Error rate calculating means for calculating and outputting an error rate at the time of detection of a land pre-pit signal included in the signal; and setting the predetermined coefficient to a value greater than 1.0 and Coefficient setting means for setting the pit signal to a value within a detectable range.

According to a fourth aspect of the present invention, there is provided a recording and / or reproducing apparatus according to the present invention, wherein a wobbling groove wobbled at a predetermined frequency and serves as a recording track of an information signal, and at least address information at a predetermined wobbling cycle interval. In a recording and / or reproducing apparatus for recording and / or reproducing the information signal on a disk-shaped recording medium in which lands pre-recorded as land prepits are alternately formed spirally or concentrically, When a beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium.
A coefficient multiplying means for receiving light in a second light receiving region, multiplying one of the light receiving outputs of the first and second light receiving regions by a predetermined coefficient, and outputting the result; A push-pull signal generating means for outputting, as a radial push-pull signal, a difference obtained by subtracting the output of the result of the multiplication processing by the coefficient multiplying means from the other light-receiving output of the second light-receiving area; A lens shift amount detecting unit that detects a lens shift amount in a radial direction from an optical axis center of an objective lens of an optical pickup that irradiates the medium with the light beam, and outputs the lens shift amount, based on the lens shift amount. And coefficient setting means for setting the value of the predetermined coefficient to a value larger than 1.0 and within a range in which the land pre-pit signal can be detected.

According to a fifth aspect of the present invention, there is provided a recording and / or reproducing method according to the present invention, wherein a wobbling groove which is wobbled at a predetermined frequency and serves as a recording track of an information signal, and at least address information at a predetermined wobbling cycle interval. In a recording and / or reproducing method for recording and / or reproducing the information signal on a disk-shaped recording medium in which lands pre-recorded as land prepits are alternately formed spirally or concentrically, When a beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium.
A coefficient multiplying step of receiving light in a second light receiving area, multiplying one of the light receiving outputs of the first and second light receiving areas by a predetermined coefficient and outputting the result, A push-pull signal generating step of outputting, as a radial push-pull signal, a difference obtained by subtracting an output of a result of the multiplication processing in the coefficient multiplying step from the other light-receiving output of the second light-receiving area; A land pre-pit signal corresponding to the land pre-pit of the land is extracted from the signal, a land pre-pit signal amplitude detecting step of detecting and outputting the amplitude of the land pre-pit signal, and the wobbling from the radial push-pull signal. A wobbling signal for extracting a wobbling signal of a groove, detecting the amplitude of the wobbling signal, and outputting the detected wobbling signal. An amplitude detection step, the amplitude of the land prepit signal, or, based on the amplitude of the amplitude and the wobble signal of the land pre-pit signal,
A coefficient setting step of setting the value of the predetermined coefficient to a value larger than 1.0 and within a range in which the land pre-pit signal can be detected.

According to a sixth aspect of the present invention, there is provided a recording and / or reproducing method according to the present invention, wherein a wobbling groove which is wobbled at a predetermined frequency and serves as a recording track of an information signal, and at least address information at a predetermined wobbling cycle interval. In a recording and / or reproducing method for recording and / or reproducing the information signal on a disk-shaped recording medium in which lands pre-recorded as land prepits are alternately formed spirally or concentrically, When a beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium.
A coefficient multiplying step of receiving light in a second light receiving area, multiplying one of the light receiving outputs of the first and second light receiving areas by a predetermined coefficient and outputting the result, A push-pull signal generating step of outputting, as a radial push-pull signal, a difference obtained by subtracting an output of a result of the multiplication processing in the coefficient multiplying step from the other light-receiving output of the second light-receiving area; A land pre-pit signal corresponding to the land pre-pit of the land is extracted from the signal, a land pre-pit signal amplitude detecting step of detecting and outputting the amplitude of the land pre-pit signal, and the wobbling from the radial push-pull signal. A wobbling signal for extracting a wobbling signal of a groove, detecting the amplitude of the wobbling signal, and outputting the detected wobbling signal. An amplitude detection step, the first,
A sum signal generating step of summing the respective light receiving outputs of the second light receiving region and outputting a sum signal; and dividing the amplitude of the land prepit signal by the sum signal to obtain a normalized land prepit. A normalized land pre-pit signal amplitude generation step of outputting a signal amplitude, and a normalized wobbling signal amplitude generation of outputting a normalized wobbling signal amplitude by dividing the wobbling signal amplitude by the sum signal. And, based on the amplitude of the normalized land pre-pit signal, or the amplitude of the normalized land pre-pit signal and the amplitude of the normalized wobbling signal, set the value of the predetermined coefficient to 1 And a coefficient setting step of setting the land pre-pit signal to a value within a detectable range.

According to a seventh aspect of the present invention, there is provided a recording and / or reproducing method according to the present invention, wherein a wobbling groove which is wobbled at a predetermined frequency and serves as a recording track of an information signal, and at least address information at a predetermined wobbling cycle interval. In a recording and / or reproducing method for recording and / or reproducing the information signal on a disk-shaped recording medium in which lands pre-recorded as land prepits are alternately formed spirally or concentrically, When a beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium.
A coefficient multiplying step of receiving light in a second light receiving area, multiplying one of the light receiving outputs of the first and second light receiving areas by a predetermined coefficient and outputting the result, A push-pull signal generating step of outputting, as a radial push-pull signal, a difference obtained by subtracting an output of a result of the multiplication processing in the coefficient multiplying step from the other light-receiving output of the second light-receiving area; An error rate calculating step of calculating and outputting an error rate at the time of detection of a land pre-pit signal included in the signal; and, based on the error rate, setting the value of the predetermined coefficient to be greater than 1.0 and Coefficient setting step of setting the pit signal to a value within a detectable range.

Further, according to the present invention, there is provided a recording and / or reproducing method according to the present invention, wherein a wobbling groove wobbled at a predetermined frequency and serves as a recording track of an information signal, and at least address information is recorded at a predetermined wobbling cycle interval. In a recording and / or reproducing method for recording and / or reproducing the information signal on a disk-shaped recording medium in which lands pre-recorded as land prepits are alternately formed spirally or concentrically, When a beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium.
A coefficient multiplying step of receiving light in a second light receiving area, multiplying one of the light receiving outputs of the first and second light receiving areas by a predetermined coefficient and outputting the result, A push-pull signal generating step of outputting, as a radial push-pull signal, a difference obtained by subtracting an output of a result of the multiplication processing in the coefficient multiplying step from the other light-receiving output of the second light-receiving area; A lens shift amount detecting step of detecting a lens shift amount in a radial direction from an optical axis center of an objective lens of an optical pickup for irradiating the medium with the light beam, and outputting the lens shift amount, based on the lens shift amount. Setting the value of the predetermined coefficient to a value larger than 1.0 and within a range in which the land pre-pit signal can be detected.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A recording and / or reproducing apparatus and method according to the present invention are applicable to a DVD-R or a DVD-RW (hereinafter, referred to as a DVD-RW).
(Collectively referred to as DVDs).

First, as shown in FIG. 1, a DVD 31 used in the disk recording / reproducing apparatus of this embodiment has a concave wobbling groove 32 and a convex land 33 on one surface of a disk-shaped transparent substrate K. Are formed alternately spirally or concentrically by injection molding or the like. A dye film 35 as a data recording layer is formed on the wobbling groove 32 and the land 33, and recording light modulated according to data to be recorded on the dye film 35 (hereinafter referred to as recording data). By irradiating the beam B from the other surface side of the transparent substrate K, a pit row corresponding to the recording data is formed irreversibly.

The DVD 31 has a wobbling groove 32 wobbled in response to a wobbling signal having a predetermined frequency component. The wobbling groove 32 serves as a data recording track for recording the recording data. ing.

In the DVD 31, land pre-pits 34 in which, for example, address information (absolute position information) and the like on an optical disk surface are recorded at predetermined wobbling cycle intervals are provided on lands 33 between adjacent wobbling grooves 32. It is formed in advance.

On the dye film 35, a gold vapor deposition film 36 is formed. In the DVD 31, when the recorded data recorded on the data recording track is reproduced, the reproducing light beam B applied to the data recording track is reflected by the gold vapor-deposited film 36 with a high reflectance. ing.
Further, a protective film 37 is formed on the gold vapor-deposited film 36.

When recording data on or reproducing data from such a DVD 31, the wobbling frequency of the wobbling groove 32 provided as a data recording track is detected, and the DVD 31 is rotationally driven based on the wobbling frequency. It is supposed to be. Further, address information and the like are detected from the land pre-pits 34, and a recording position is detected based on the address information.
The recording data is recorded on the wobbling groove 32 and reproduced.

Here, when recording the recording data, the recording light beam B modulated according to the recording data is irradiated such that the center of the light spot coincides with the center of the wobbling groove 32. As a result, a pit row corresponding to the recording data is formed on the data recording track on the wobbling groove 32, and recording of the recording data is performed. At this time, the size of the light spot SP of the recording light beam B is irradiated not only on the wobbling groove 32 but also on the land 33 between the adjacent wobbling grooves 32 as shown in FIG. It is set as follows.

Then, a part of the reflected light of the light spot SP applied to the land 33 is reflected by the wobbling groove 3.
2, the light is received by a photodetector divided by a dividing line optically parallel to the rotation direction of the DVD 31, and based on the output from the photodetector, for example, a push-pull signal is formed and tracking servo is applied. Further, a wobbling signal of the wobbling groove 32 is extracted from the photodetector, and a recording clock synchronized with the rotation of the DVD 31 is formed based on a wobbling pulse generated by binarizing the wobbling signal.

Next, a recording format of address information recorded in advance on the DVD 31 will be described with reference to FIG.

In FIG. 2, the upper part shows the recording format of the recording data, and the lower part shows the wobbling state of the wobbling groove 32 for recording the recording data (the meandering state confirmed when the wobbling groove 32 is viewed in a plan view). Is shown. An upward arrow between the upper row showing the recording format of the recording data and the lower row showing the wobbling state of the wobbling groove 32 schematically shows the position where the land prepit 34 is formed.

The wobbling state of the wobbling groove 32 in FIG. 2 is shown with an amplitude larger than the actual amplitude for easy understanding. Also,
Actually, the recording data is recorded on the center line of the wobbling groove 32 as described above.

As shown in FIG. 2, recording data recorded on the DVD 31 is divided in advance into sync frames as information units. One recording sector is composed of 26 sync frames. Also, 1
6 recording sectors and one ECC (Error
(Correcting Code) block.

One sync frame has a length of 1488 times (1488T) the unit length T corresponding to the pit interval defined by the recording format when recording the recording data. Then, in a portion corresponding to the length of 14T at the beginning of one sync frame, synchronization information SY for synchronizing each sync frame is recorded.

On the other hand, the address information (land pre-pits 34) recorded on the DVD 31 is recorded in advance for each sync frame of the recording data at the time of manufacturing the optical disc. Here, when the address information is recorded on the DVD 31 by the land pre-pits 34, the synchronization signal in the address information is indicated on the land 33 adjacent to the area where the synchronization information SY in each sync frame of the recording data is recorded. As a result, a land pre-pit 34 (land pre-pit B0) indicated by an arrow B0 in FIG. 2 is formed, and an address to be recorded on a land 33 adjacent to the first half of the sync frame other than the synchronization information SY. Both or one of the land pre-pits 34 (land pre-pit B1, land pre-pit B2) indicated by arrows B1 and B2 in FIG. 2 are formed as information contents.

However, in the first half of the sync frame other than the synchronization information SY, the land pre-pit B1 and the land pre-pit B2 may not be formed depending on the contents of the address information to be recorded.

At this time, in one recording sector, land pre-pits 34 are formed for every other sync frame, and address information and the like are recorded. One recording sector is composed of an EVEN frame and an ODD
When the land pre-pits 34 are formed in the EVEN frame, the land pre-pits 34 are not formed in the ODD frame, as shown by the solid line upward arrow in FIG.

On the other hand, when the land pre-pits 34 are formed in the ODD frame, as shown by the upward arrow in FIG. 2, the land pre-pits 3 are formed in the EVEN frame.
4 is not formed.

When the land pre-pit 34 is formed in the EVEN frame, the land pre-pit B in the sync frame at the head of the recording sector is used.
0, land pre-pits B1 and land pre-pits B2 are all formed, and in a sync frame other than the head of the recording sector, when the address information to be recorded in the sync frame is "1", Land pre-pit B0 and land pre-pit B
When the address information to be recorded is "0", only the land pre-pit B0 and the land pre-pit B1 are formed.

When the land pre-pits 34 are formed in the ODD frame, only the land pre-pit B0 and the land pre-pit B1 are formed in the sync frame at the head of the recording sector. Is the same as that of the EVEN frame.

Whether the land pre-pit 34 is formed in the sync frame of the EVEN frame or the ODD frame is determined depending on the position of the land pre-pit 34 previously formed on the adjacent land 33. .

That is, the land pre-pits 34 are usually formed in the EVEN frame. However, when the land pre-pits 34 are formed in the EVEN frame, the land pre-pits 34 are adjacent to the land pre-pits 34 formed earlier. If the land pre-pits 34 on the lands 33 overlap in the radial direction of the DVD 31, the land pre-pits 34 are formed in the ODD frame.

In other words, as shown in FIG. 3, the land pre-pits 34
31 are formed so as not to overlap in the radial direction. By forming the land pre-pits 34 in this manner, the land pre-pits 34 are not formed at the positions overlapping the radial direction of the DVD 31 between the adjacent lands 33. The effect of land pre-pit crosstalk on adjacent lands can be reduced.

In FIG. 3, the sync frame indicated by a black band at the top on the land 33 is the sync frame on which the land prepits 34 are formed, and the sync frame indicated by a white band at the top. The frame is a sync frame in which the land pre-pits 34 are not formed.

On the other hand, the wobbling groove 32 is wobbled at a constant wobbling frequency f0 of about 140 KHz (frequency at which a wobbling signal for eight cycles of wobble is contained in one sync frame) over all the sync frames. At this time, by extracting the wobbling frequency f0 of the wobbling signal, a signal for controlling the rotation operation of the DVD 31 is detected, and a recording clock signal is generated.

In order to make the phase relationship between the land pre-pits 34 and the wobbling signal constant, the land pre-pits B0 to B2 are formed in advance at the time of manufacturing the optical disc, and the land pre-pits B0 to 186T (1488T) are formed.
/ 8) The land pre-pits B1 and the land pre-pits B2 are respectively formed beforehand at intervals of minutes.

The land pre-pits 34 are formed on the lands 33 for every other sync frame as described above, and are formed between adjacent lands 33 so as not to overlap in the radial direction of the DVD 31. . Therefore, two lands 3 adjacent to one wobbling groove 32
In 3, the land pre-pits 34 appear every 16 wobble periods of the wobbling groove 32, and the land pre-pits 34 appear alternately on both sides of the wobbling groove 32.

FIG. 4 is a block diagram of a disk recording / reproducing apparatus according to the embodiment. As can be seen from FIG. 4, the disk recording / reproducing apparatus according to the present embodiment has a D
An optical pickup 2 for recording / reproducing data by irradiating a light beam from a semiconductor laser (not shown) to the VD 31 via an objective lens (not shown), and reproducing and outputting a predetermined output from the optical pickup 2 And a preamplifier 3 for amplifying and outputting the amplified signal.

FIG. 5A shows that the light receiving element PD (Photo Detector) in the optical pickup 2 is located at the center of the wobbling groove 32, and that the light receiving element PD is located on the land 33 on the right land 33 in the drawing. FIG. 4 is a schematic diagram schematically showing a state in which a pit is detected.

The light receiving element PD is formed in a substantially rectangular shape, and the light receiving area is divided into four equal parts by a straight line along the radial direction of the DVD 31 and a straight line along the track direction. The light spot SP imaged on the light receiving element PD is a set of two light receiving areas A and B on the outer circumference of the DVD 31 (optical disc) and a set of two light receiving areas C and D on the inner circumference of the DVD 31. And the two sets are formed, and the straight line along the recording track direction of the DVD 31 is divided into two.

When a light receiving output is output from the light receiving element PD, as shown in FIG.
The signal (A + B) obtained by adding the light receiving signals of the two light receiving areas A and B on the outer peripheral side of the DVD and the light receiving signal of the two light receiving areas C and D on the inner peripheral side of the DVD 31 are added (C + D At this time, on the light receiving element PD, the brightness is unbalanced between the outer peripheral side and the inner peripheral side of the DVD 31 due to the influence of the diffraction phenomenon of the light beam B on the land pre-pits 34 at this time. (A
Both the (+ B) signal and the (C + D) signal are output in a state where they are inverted from each other above the 0 level.

At this time, the output amplitude of the (A + B) signal and
It is a necessary condition that the output amplitude of the (C + D) signal is substantially the same level. If the two are not substantially the same due to the adjustment state of the optical pickup 2 or the like, the difference is calculated by the RPP generation circuit 8 as described later. Before generating the signal (A +
B) The addition circuits 4 and (C + D) may be adjusted by an appropriate adjustment circuit so that the output amplitudes of the two circuits become substantially the same level.

Thereafter, when a radial push-pull signal is generated by the (A + B) signal and the (C + D) signal output from the light receiving element PD, the (C + D) signal and
(A + B) A predetermined coefficient k for inverting the polarity of the signal
乗 算 −k (A +
B) Since the {signal} is obtained above and below the 0 level as shown in FIG. 5 (c), the difference signal {(C + D) −k (A + B)) obtained by taking the difference between these signals is radial. It is generated as a push-pull signal. At this time, in FIG. 5B, the land pre-pit signal (LP
P signal) is a signal (A +) that is directed to the 0 level side (downward) around the wobbling signal (WBL signal).
A predetermined coefficient k may be multiplied by a minus (−) sign on the B) side. If the land pre-pit signal (LPP signal) is directed downward on the (C + D) side, unlike the drawing, This determination may be performed by multiplication. However, since this determination is not performed in the apparatus, and which side is to be multiplied can be set in advance, the coefficient multiplication is performed on the (A + B) addition circuit 4 side as in the embodiment. What is necessary is just to connect the circuit 6.

For this reason, the disc recording / reproducing apparatus is
An (A + B) addition circuit 4 for detecting a signal (A + B) obtained by adding the respective light receiving signals of the two light receiving areas A and B on the outer peripheral side of the DVD 31, and two light receiving areas C and light receiving on the inner peripheral side of the DVD 31 Each light receiving signal of the area D is added (C
(C + D) adding circuit 5 for detecting the (+ D) signal.

The disk recording / reproducing apparatus is provided with (A
+ B) Invert the polarity of the (A + B) signal from the adding circuit 4 and multiply by a predetermined coefficient k {−k (A + B)}
And a coefficient multiplying circuit 6 for outputting.

In the disk recording / reproducing apparatus, the predetermined coefficient k is determined according to the detection output of the radial push-pull signal, the error rate at the time of detecting the land pre-pit signal, and the shift amount of the objective lens of the optical pickup 2. By changing this, the land pre-pit (L
The detection accuracy of PP) is improved.

Further, the disc recording / reproducing apparatus has a (C
+ D) signal and an {-k (A + B)} signal to generate a radial push-pull signal {(C + D) -k (A + B)}, and the radial push-pull signal from the RPP generation circuit 8 A binarizing circuit 9 for binarizing a land pre-pit signal (LPP signal) included in
The land pre-pit signal (L) binarized by the binarization circuit 9
LPP for decoding address information of PP signal)
It has a decoding circuit 10 and a CPU 11 which calculates an error rate of the land pre-pit signal decoded by the LPP decoding circuit 10 and outputs this error rate.

The disc recording / reproducing apparatus is provided with (A
+ B) an RF circuit 7 for adding the (A + B) signal from the adding circuit 4 and the (C + D) signal from the (C + D) adding circuit 5 to generate a sum signal {RF signal: (A + B + C + D)}; A land pre-pit signal (LPP signal) is extracted from the radial push-pull signal from the circuit 8, the amplitude of the land pre-pit signal is detected, and the LPP signal is detected.
LPP output to the b generation circuit 14 and the coefficient setting circuit 16
Amplitude detection circuit (land pre-pit signal amplitude detection circuit) 1
2 and a wobbling signal (WBL signal) of the recording track is extracted from the radial push-pull signal from the RPP generation circuit 8, the amplitude of the wobbling signal is detected, and the WBL is output to the WBLb generation circuit 15 and the coefficient setting circuit 16. Amplitude detection circuit (wobbling signal amplitude detection circuit)
13 are provided.

Further, the disc recording / reproducing apparatus has an LP
The level of the land pre-pit signal (LPP signal) extracted by the P amplitude detection circuit 12 is normalized to the level of the sum signal (A + B + C + D) generated by the RF circuit 7 (hereinafter, LPPb). LPPb generation circuit (normalized land pre-pit signal amplitude detection circuit) 14 and WBL amplitude detection circuit 13
The level of the wobbling signal extracted by
A WBLb generation circuit (normalized wobbling signal amplitude detection circuit) 15 for outputting as a wobbling signal (hereinafter, referred to as a WBLb signal) normalized to the level of the sum signal (A + B + C + D) generated by the optical pickup 2
A lens shift amount detection circuit 17 for detecting a lens shift amount in the radial direction from the optical axis center of the objective lens and outputting the lens shift amount.

Further, the disc recording / reproducing apparatus has a CP
Error rate when detecting a land pre-pit signal from U11, amplitude of land pre-pit signal from LPP amplitude detection circuit 12, amplitude of wobbling signal from WBL amplitude detection circuit 13, normalized LPPb from LPPb generation circuit 14. A coefficient setting circuit 16 for setting a predetermined coefficient k of the coefficient multiplying circuit 6 according to the signal, the normalized WBLb signal from the WBLb generation circuit 15, and the lens shift amount detected by the lens shift amount detection circuit 17; are doing. A set of the amplitude of the land pre-pit signal from the LPP amplitude detection circuit 12, the amplitude of the wobbling signal from the WBL amplitude detection circuit 13, or the normalized LPPb signal from the LPPb generation circuit 14 and the signal from the WBLb generation circuit 15 Only one of the normalized WBLb signal sets may be connected to the coefficient setting circuit 16.

Next, a description will be given of a land pre-pit (LPP) detecting operation, which is a main part of the present invention, in the disk recording / reproducing apparatus of the present embodiment having such a configuration.

In FIGS. 6, 7 and 8 described below, the wobbling signal and the LPP signal are approximated by straight lines, which are different from those shown in FIGS. 12 and 13, but are simplified. It is only displayed.

Although the present invention involves reproducing the unrecorded portion and measuring the relevant basic parameters for the disc, in an actual recording / reproducing apparatus, the unrecorded area on the disc can be recognized. The above parameters can be obtained by seeking to the area. The lead-in area at the innermost circumference of the disc or the lead-out area at the outermost circumference of the disc is a part to be recorded after all the user data is recorded on the disc. Do not record. The measurement of the relevant basic parameters for the disk according to the present invention can be performed for the lead-in area or the lead-out area.

First, FIG. 6 shows a sum signal output (A + B +) from the RF circuit 7 when an unrecorded portion of the DVD 31 is reproduced.
C + D) and the radial push-pull signal {(C + D) -k (A + B)} from the RPP generation circuit 8. As can be seen from FIG. 6, the signals A to D are added. The level of the obtained RF signal is higher than the level of the radial push-pull signal which is a difference signal obtained by subtracting the {-k (A + B)} signal from the (C + D) signal.

The radial push-pull signal includes 0
The wobbling signal (W
BL preamble signal (LPP signal) appearing at the timing of the phase of the wobbling signal at 90 °.
Are superimposed. At this time, the sum signal (A + B
+ C + D) and a wobbling signal (WBL)
, And the amplitude L1 of the land pre-pit signal (LPP signal) are values between the 0 level and each signal in the upper part of the figure. The land pre-pit signal (L
(PP signal) is a diagram showing a signal on the normal side with respect to the track, and the illustration of an unusual land prepit signal (LPP signal) on the opposite side is omitted.

FIG. 7 shows a radial push-pull signal ｛(C +
D) -k (A + B)} is divided into a (C + D) signal and a {-k (A + B)} signal whose polarity is inverted. As can be seen from FIG. 7, (C + D) The signal appears on the positive polarity side with the 0 level as the boundary, and ｛−k (A +
B) The｝ signal appears on the negative polarity side from the 0 level. Then, the (C + D) signal and the {−k (A + B)} signal are
It can be seen that a land pre-pit signal (LPP signal) which appears at the timing of the phase of the wobbling signal at 90 ° is superimposed on each wobbling signal.

At this time, the amplitude R2 up to the center level of the (C + D) signal on the positive polarity side and ｛−k (A +
B) The amplitude kR2 up to the center level of the｝ signal is displayed with reference to the 0 level as shown in the figure. Also, the amplitude W of the wobbling signal (WBL signal) corresponding to the (C + D) signal
2 and the amplitude L2 of the land pre-pit signal (LPP signal)
Is a value between the center level of the (C + D) signal and the top of each signal in the upper part of the figure. Further, {−k (A + B)}
Amplitude kW of wobbling signal (WBL) corresponding to signal
2 and the amplitude kL of the land pre-pit signal (LPP signal)
2 is a value from the center level of the {-k (A + B)} signal to the top of each signal in the upper part of the figure.

Next, FIG. 8 shows a state when an information signal is recorded on the wobbling groove 32 on the DVD 31. For example, when the information signal is recorded with a pulsed light beam B, the irradiation of the light beam B is performed. A portion having a large light amount (a portion corresponding to “information signal 1”) is defined as a high-power irradiating portion, and a portion having a small irradiation light amount of the light beam B (portion corresponding to “information signal 0”) is defined as a low-power irradiating portion. In this case, the envelope of the high-power irradiation unit and the envelope of the low-power irradiation unit are separately shown for the (C + D) signal on the positive polarity side and the {-k (A + B)} signal on the negative polarity side. is there.

As can be seen from FIG. 8, when both the (C + D) signal and the {-k (A + B)} signal have a high-power irradiating section and a low-power irradiating section, the (C + D) signal and the ｛-k (A + B) signal It will be understood that each level of the signal is a different level. Since such a level difference occurs between the high power irradiating section and the low power irradiating section, erroneous detection of the land pre-pit signal occurs in the subsequent stage.

In the following description, the recording time is described. At the time of reproduction, the portion where the recording pits are formed on the optical disk corresponds to the low-power irradiation portion, and the unrecorded portion where no recording pits are formed is formed. Since it is only necessary to detect the land pre-pit signal assuming that the part corresponds to the high-power irradiation part, the description at the time of reproduction is omitted.

Therefore, the disk recording / reproducing apparatus according to the present embodiment variably controls a predetermined coefficient k to be multiplied to obtain an inverted {-k (A + B)} signal, thereby obtaining a radial push-pull signal { (C + D) -k (A +
In B), the level on the {−k (A + B)} signal side is adjusted by a predetermined coefficient k to improve the detection accuracy of the land pre-pit signal in the subsequent stage. Note that a {(A + B) −k (C + D)} signal may be used as the radial push-pull signal. In this case, the level on the {−k (C + D)} signal side may be adjusted. In the description above, the case where the level on the {−k (A + B)} signal side is adjusted will be described.

That is, first, at the time of recording (or at the time of reproduction)
Is irradiated with a recording (or reproducing) light beam from the optical pickup 2, and the optical pickup 2 transmits the reflected light of this light beam to the four-divided light receiving element P described with reference to FIG.
D, the light receiving signals of the light receiving area A and the light receiving area B are supplied to the (A + B) adding circuit 4 via the preamplifier 3, and the light receiving signals of the light receiving area C and the light receiving area D are supplied via the preamplifier 3. (C + D) is supplied to the addition circuit 5.

The (A + B) adding circuit 4 adds each light receiving signal of the light receiving area A and the light receiving signal of the light receiving area B to obtain (A + B).
B) A signal is generated and supplied to the coefficient multiplying circuit 6 and to the RF circuit 7. Further, the (C + D) adding circuit 5 adds the respective light receiving signals of the light receiving region C and the light receiving region D to generate a (C + D) signal,
The signal is supplied to the generation circuit 8 and to the RF circuit 7.

The RF circuit 7 outputs the (A + B) signal and the (C +
D) By adding the signals, (A + B + C +
D) A sum signal, which is a signal, is generated and supplied to the LPPb generation circuit 14 and the WBLb generation circuit 15, respectively.

As the initial value of the coefficient of the coefficient multiplying circuit 6, a predetermined coefficient k is set to "1" so that the level of the input (A + B) signal is output without being changed. For this reason, in this case, the (A + B) signal supplied to the coefficient multiplying circuit 6 is supplied to the RPP generating circuit 8 in the initial state as it is without being changed in level just because the polarity is inverted. Since the predetermined coefficient k is varied by feedback from the coefficient setting circuit 16 as described later, the following description of the RPP generation circuit 8 will be made using the predetermined coefficient k.

The RPP generation circuit 8 computes a difference signal obtained by subtracting the {-k (A + B) signal} whose polarity has been inverted from the (C + D) signal to obtain a radial push-pull signal {(C + D) -k (A + B). ) A signal｝ is generated, and this radial push-pull signal is supplied to the binarization circuit 9, the LPP amplitude detection circuit 12, and the WBL amplitude detection circuit 13, respectively.

The binarization circuit 9 binarizes the land pre-pit signal (LPP signal) included in the radial push-pull signal.

The LPP amplitude detection circuit 12 is provided with a land pre-pit (LPP) included in the radial push-pull signal.
The component is extracted, the amplitude of the land pre-pit signal (LPP signal) is detected, and this detection output is supplied to the LPPb generation circuit 14 and the coefficient setting circuit 16.

The WBL amplitude detection circuit 13 extracts the wobble (WBL) component contained in the radial push-pull signal, detects the amplitude of the wobbling signal (WBL signal), and outputs the detection output to the WBLb generation circuit 15 and The coefficient is supplied to a coefficient setting circuit 16.

Further, the LPPb generation circuit 14 outputs the LPPb signal included in the sum signal from the RF circuit 7 and the radial push-pull signal detected by the LPP amplitude detection circuit 12.
The LPPb signal indicating the ratio of the amplitude of the land pre-pit signal to the sum signal is calculated based on the amplitude of the component, and supplied to the coefficient setting circuit 16.

More specifically, the sum signal (A + B +) shown in FIG.
C + D) is “R1”, the amplitude of the land prepit signal is “L1”, and the amplitude of the (C + D) signal shown in FIG.
2, the amplitude of the land pre-pit signal in the (C + D) signal is “L2”, the amplitude of the {−k (A + B)} signal shown in FIG. 7 is “kR2”, and the land in the {−k (A + B)} signal. Assuming that the amplitude of the pre-pit signal is “kL2”, the LPPb generating circuit 15 calculates the normalized L by the following equation (1).
A PPb signal is generated and supplied to the coefficient setting circuit 16.

LPPb signal = L1 / R1 = kL2 / kR2 = L2 / R2 (1) Similarly, the WBLb generation circuit 15 detects the sum signal from the RF circuit 7 and the WBL amplitude detection circuit 13. The WBLb signal indicating the ratio of the amplitude of the wobbling signal to the sum signal is calculated based on the wobbling signal, and is supplied to the coefficient setting circuit 16.

Specifically, the sum signal (A + B +) shown in FIG.
The amplitude of the wobbling signal is “W1”, and the amplitude of the (C + D) signal shown in FIG. 7 is “R1”.
2 ", the amplitude of the wobbling signal in the (C + D) signal is" W2 ", the amplitude of the {-k (A + B)} signal shown in FIG. 7 is" kR2 ", and the amplitude of the wobbling signal in the {-k (A + B)} signal is shown in FIG. If the amplitude is “kW2”, the WBLb generation circuit 1
5 is WBLb normalized by the following equation (2)
A signal is generated and supplied to the coefficient setting circuit 16.

WBLb signal = W1 / R1 = kW2 / kR2 = W2 / R2 (2) On the other hand, the binarization circuit 9 is a land pre-pit signal included in the radial push-pull signal from the RPP generation circuit 8. (LPP signal) is binarized, and the binarized land pre-pit signal (LPP signal) is supplied to the LPP decoding circuit 10. The LPP decoding circuit 10 decodes address information and the like included in the land pre-pit signal (LPP signal) based on the binarized land pre-pit signal (LPP signal).

At the time of this decoding, the error rate at the time of detection of the land pre-pit signal (LPP signal) is set to CP
Supply to U11. The CPU 11 supplies the error rate to the coefficient setting circuit 16, and sets the predetermined coefficient k by an amount corresponding to the error rate when setting a predetermined coefficient k described later so that the error rate is reduced in the coefficient setting circuit 16. Is further corrected.

The lens shift amount detecting circuit 17 determines whether the center of the optical axis of the objective lens of the optical pickup 2 is shifted to the radially outer side of the DVD 31 or
It is determined whether the DVD 31 has been shifted to the inner circumference side, and
The lens shift amount is detected by ± according to the outer peripheral side and the inner peripheral side,
The lens shift amount signal indicating the lens shift amount is supplied to the coefficient setting circuit 16, and a predetermined amount corresponding to the lens shift amount shifted to the outer peripheral side or the inner peripheral side of the DVD 31 when a predetermined coefficient k described later is set. Is further corrected.

That is, in FIG. 5A described above,
When the lens shift occurs, the position of the light spot SP formed on the light receiving element PD is shifted in the radial direction of the optical disk with respect to the center of the light receiving element PD (A + B), and thus (C +
The output level of D) changes. Therefore, this output level can be corrected by correcting the lens shift amount.

Specifically, although not shown here, the lens shift amount detection circuit 17 includes a slit plate provided on a bobbin for driving the objective lens, and a light source for irradiating the slit plate with light. And a light receiving element that receives light emitted from the light source through the slit of the slit plate evenly in two divided light receiving areas (light receiving area E and light receiving area F). The difference (E−F) between the amounts of light received by the respective light receiving areas E and F is detected as a lens shift amount.

In addition to the method of mechanically detecting the amount of lens shift, it is also possible to detect the offset of the objective lens based on, for example, a radial push-pull signal and use this as the lens shift amount.

In a system for detecting a tracking error by the so-called differential push-pull method (DPP method), the DPP method itself cancels the influence of the lens shift. The lens offset cannot be detected.

Therefore, in this case, a detection system for the radial push-pull signal is provided separately from the detection system for the tracking error by the DPP method, and the detection system detects the radial push-pull signal while applying the tracking servo by the DPP method. What is necessary is just to detect the offset of the objective lens based on the obtained radial push-pull signal.

Next, as described above, the predetermined coefficient k set in the coefficient multiplying circuit 6 is set to “k =
1 ”, and thereafter, the coefficient setting circuit 16
Based on the LPPb signal, WBLb signal, error rate, and lens shift amount signal fed back when the predetermined coefficient k is set to “1”, the predetermined coefficient k of the coefficient multiplication circuit 6 is calculated as described below. Optimal variable control.

More specifically, conventionally, a mini-disc (MD) has been used as a recording medium in which recording tracks are wobbled.
And CD-R are known, but this MD and CD
In the -R recording / reproducing apparatus, adjustment is made so that recording noise is minimized at the cross point (zero cross point) between the wobbling signal and the 0 level shown in FIG. Through extensive research, it has been found that by making adjustments so that recording noise is minimized at a point slightly distant from the zero cross point, the detection accuracy of the land pre-pit signal is improved.

The details will be described below. First, FIG.
The wobbling signal component in the radial push-pull signal is temporarily set to zero, the wobbling signal component is removed, and only the land pre-pit signal in the radial push-pull signal is focused on. The positive side from the 0 level is (C +
D) shows a land pre-pit signal of a high-power irradiation part and a land pre-pit signal of a low-power irradiation part of the signal.
A land pre-pit signal of a high power irradiation part and a land pre-pit signal of a low power irradiation part are shown.

The {-k (A + B)} signal is obtained by simulating a predetermined coefficient k to be multiplied by, for example, appropriately changing the coefficient from about 0.9 to about 1.6. 2 shows a pre-pit signal and a land pre-pit signal of a high power irradiation unit.

The (C + D) signal indicates the under level of the land pre-pit signal of the low-power irradiation section by “m”.
1 ", the under-level of the land pre-pit signal of the high power irradiation unit is" m2 ", the peak level with respect to the under-level of the land pre-pit signal of the low power irradiation unit is" a ", and the land pre-pit signal of the high power irradiation unit is The peak level with respect to the under level is “b”, and a /
When m1 = b / m2 = L, it is the amplitude from the top of the land pre-pit signal waveform of the high power irradiation section to the top of the land pre-pit signal waveform of the low power irradiation section (C
+ D) The amplitude LB1 of the signal is calculated by the following (Equation 3).

LB1 = m2−m1 + ba = m2−m1 + L × m2−L × m1 (Equation 3) In the same manner as described above, the {−k (A + B)} signal is a land preamp of the low power irradiation unit. The under level of the pit signal is "-km1", the under level of the land pre-pit signal of the high power irradiation section is "-km2", the peak level with respect to the under level of the land pre-pit signal of the low power irradiation section is "ka", and the high level. The peak level with respect to the under level of the land pre-pit signal of the power irradiation unit is set to "kb", and -ka / -km1 = -kb / -km2 =
When L, the amplitude LB2 of the {-k (A + B)} signal, which is the amplitude from the top of the land prepit signal waveform of the low power irradiation section to the top of the land prepit signal waveform of the high power irradiation section, is as follows: It is calculated by equation (4).

LB2 = k (m2−m1 + ab) = k (m2−m1 + L × m1−L × m2) (4) Regarding the relationship between the above (3) and (4), It will be described later.

Next, FIGS. 10 and 11 show that the land pre-pit signal in the radial push-pull signal {(C + D) -k (A + B)} is binarized in the binarization circuit 9 without fail. Focusing on only the land pre-pit signal in the (C + D) signal and the {-k (A + B)} signal, how the allowable variation width (slice window width) of this land pre-pit signal changes by a predetermined coefficient k. By simulating the above, the slice window width that can reliably detect both the land pre-pit signal of the high-power irradiation unit and the land pre-pit signal of the low-power irradiation unit simultaneously according to the predetermined coefficient k I'm asking. At this time, the slice window width for the land pre-pit signal is 2
This is set in the value conversion circuit 9.

First, in the case of FIGS. 10A to 10F,
This is a special case where a / m1 = b / m2 = L described with reference to FIG.
It is set to simulate.

FIG. 10B shows that the predetermined coefficient k is "1.0".
, And in this case, the conventional radial push-pull signal ｛(C + D) − (A +
B) The case of obtaining｝. In this example, the under level of the land pre-pit signal of the high power irradiation unit and the under level of the land pre-pit signal of the low power irradiation unit both have the same reference level (hereinafter referred to as 0 level). Can be satisfactorily detected, but the detection of the land pre-pit signal cannot be improved.

That is, the slice window width for detecting the land pre-pit signal of the high-power irradiation section and the land pre-pit signal of the low-power irradiation section depends on the peak level of the land pre-pit signal of the low-power irradiation section, 0
Since the level difference from the level is 4.0, and the value of the slice window width = 4.0 is slightly small, both land pre-pit signals cannot be reliably detected.

FIG. 1B is different from FIG.
As shown in FIG. 0 (a), when the predetermined coefficient k is slightly smaller than “1.0” and is set to “0.96”, the under-level of the land pre-pit signal of the high power irradiating unit is reduced. , The under-level of the land pre-pit signal of the low-power irradiator rises above the 0 level, and
The slice window width for detecting both land pre-pit signals has a level difference of 0.92 between the peak level of the land pre-pit signal of the low-power irradiation section and the under-level of the land pre-pit signal of the high power irradiation section. The value of the slice window width = 0.92 is shown in FIG.
0 (b) is extremely small, making it difficult to detect a land pre-pit signal, and the wobbling signal, not shown, is slightly inferior to the case of FIG. 10 (b).

On the other hand, FIG.
As shown in FIG. 0 (c), when the predetermined coefficient k is slightly larger than “1.0” and is set to “1.1”, the under-level of the land pre-pit signal of the high power irradiation unit is reduced. The under-level of the land pre-pit signal of the low-power irradiating unit is lower than 0 level, and the slice window width for detecting both land pre-pit signals is the land pre-pit signal of the low-power irradiating unit. And the under level of the land pre-pit signal of the low power irradiating section is 4.1, and this slice window width value = 4.1 is the same as FIG.
Since it is slightly larger than (b), detection of the land pre-pit signal is slightly improved.

At this time, although the wobbling signal not shown is slightly inferior to the case of FIG. 10B, it is more important to surely detect the land pre-pit signal than to deteriorate the detection of the wobbling signal. Yes, below Figure 1
Even in the case of 0 (d) to FIG. 10 (f), the detection of the wobbling signal gradually deteriorates.

Further, as shown in FIG. 10D, when the predetermined coefficient k is set to “1.2” which is larger than that of FIG. 10C, the same tendency as in FIG. Although
The slice window width for detecting both land prepit signals has a level difference of 4.4 between the peak level of the land prepit signal of the low power irradiation unit and the underlevel of the land prepit signal of the low power irradiation unit. The value of the slice window width = 4.4 is a good value for reliably detecting both land pre-pit signals with high reliability.

Further, as shown in FIG. 10E, when the predetermined coefficient k is set to “1.5” which is larger than that of FIG. In a state where the under level of the signal and the under level of the land pre-pit signal of the low power irradiating unit are both lower than 0 level, the peak level of the land pre pit signal of the high power irradiating unit and the Both the peak level of the land pre-pit signal and the peak level coincide with each other at 0 level.

The slice window width for detecting both land pre-pit signals is 0 level (= the peak level of the land pre-pit signal of the high-power irradiation section and the low-power irradiation section) and the low level irradiation section. The level difference between the land pre-pit signal and the under level is 5.0, and this slice window width value = 5.0 is the maximum value that can reliably detect both land pre-pit signals. The predetermined coefficient k = 1.5 under the condition of / m1 = b / m2 = L is the theoretical upper limit. The method for obtaining the theoretical lower limit of the predetermined coefficient k will be described later.

Further, as shown in FIG. 10F, when the predetermined coefficient k is set to “1.6” which is larger than that of FIG. Both the peak level of the signal and the peak level of the land pre-pit signal of the low-power irradiating unit fall below 0 level, and the peak level of the land pre-pit signal of the high-power irradiating unit is lower than that of the land of the low-power irradiating unit. The slice window width for detecting both land pre-pit signals is lower than the peak level of the land pre-pit signal of the high-power irradiator, and the slice window width for detecting both land pre-pit signals is lower than the peak level of the low-power irradiator. The level difference from the under level of the land pre-pit signal is 2.0
The value of the slice window width = 2.0 corresponds to FIG.
Although the predetermined coefficient k is slightly increased by 0.1 from the case of 0 (e), the coefficient k is extremely reduced, and the detection of both land prepit signals is extremely deteriorated.

Accordingly, as shown in FIG. 10 (e), the case where the predetermined coefficient k is "1.5" is a theoretical upper limit value. Since there is no margin in the direction in which the coefficient k becomes larger than 1.5, as shown in FIG. 10D, the predetermined coefficient k is set to “1.2” to “1.2” in terms of reliability and safety. The case of “1.4” (partially omitted) is a practical value under the condition of a / m1 = b / m2 = L.

Here, as shown in FIG. 10E, when the predetermined coefficient k takes the theoretical upper limit under the condition of a / m1 = b / m2 = L, as described above, The amplitude LB of the land pre-pit signal in the (C + D) signal according to (Equation 3)
When the amplitude LB2 of the land pre-pit signal in the {-k (A + B)} signal obtained by the equation (4) becomes equal to the value LB2, the theoretical upper limit of the predetermined coefficient k is obtained. Accordingly, the predetermined coefficient k becomes a value calculated by the following five equations from (Equation 3) = (Equation 4).

K = {m2-m1 + L (m2-m1)} / {m2-m1 + L (m1-m2)} = {(m2-m1) (1 + L)} / {(m2-m1) (1-L)} = (1 + L) / (1-L) (Equation 5) Further, L in the above (Equation 5) is the LPPb signal normalized by the above-mentioned (Equation 1) = L1 / R1 = kL2 / kR2
= L2 / R2, which is clearly equivalent from FIG. 7, so that the above L value normalized LPP
b signal value, that is, (Equation 5) can be replaced by the following (Equation 6), whereby LP
By supplying the output result from the Pb generation circuit 14 to the coefficient setting circuit 16, a predetermined coefficient k of the theoretical upper limit is obtained by (Equation 6).

K = (1 + LPPb) / (1-LPPb) (Equation 6) Next, in the case of FIGS. 11A to 11E, a / m1 = b as described with reference to FIG. / M2 = L is not satisfied, that is, a general case where a / m1 ≠ b / m2 ≠ L. Here, the simulation is performed by setting the value of L to, for example, about 0.2. .

11 (a) to 11 (e) also show a land pre-pit signal of a high-power irradiation part and a land pre-pit of a low power irradiation part for a predetermined coefficient K in substantially the same manner as described with reference to FIG. The slice window width for reliably detecting both signals is determined. Further, the absolute value of the slaus window width obtained here is different from the absolute value obtained in FIG. 10 because, of course, factors other than the predetermined coefficient k are different.

That is, FIG. 11A shows the case where the predetermined coefficient k is set to “0.9”. In this case, the under level of the land pre-pit signal of the high power irradiation unit and the low power irradiation unit And the under level of the land pre-pit signal rises above the 0 level, and
The slice window width for detecting the land pre-pit signal of the high-power irradiation unit and the land pre-pit signal of the low-power irradiation unit is the peak level of the land pre-pit signal of the low-power irradiation unit and the peak level of the high-power irradiation unit. The level difference from the under level of the land pre-pit signal is 3.5. The value of 3.5 is a small value that makes it difficult to detect the land pre-pit signal.

FIG. 11B shows a case where the predetermined coefficient k is set to “1.0”. In this case, the conventional radial push-pull signal ｛(C + D) −
(A + B)}.

In this case, the under level of the land pre-pit signal of the high power irradiation section and the under level of the land pre-pit signal of the low power irradiation section are both the same 0 level (reference level). Although the omitted wobbling signal can be detected well, the detection of the land pre-pit signal cannot be improved. That is, the slice window width for detecting both land pre-pit signals has a level difference of 8.0 between the peak level of the land pre-pit signal of the low power irradiation unit and the 0 level, and the value of this slice window width is obtained. =
Since 8.0 is slightly smaller, both land pre-pit signals cannot be reliably detected.

FIG. 11C shows the case where the predetermined coefficient k is set to “1.1”. In this case, the under-level of the land pre-pit signal of the high-power irradiation unit and the low-power irradiation unit And the under level of the land pre-pit signal falls below the 0 level, and
The slice window width for detecting both land pre-pit signals has a level difference of 8.4 between the peak level of the land pre-pit signal of the low-power irradiation section and the under-level of the land pre-pit signal of the low power irradiation section. The value of the slice window width = 8.4 is a good value for reliably detecting both land pre-pit signals with high reliability.

FIG. 11D shows the case where the predetermined coefficient k is set to “1.2”. In this case, the under level of the land pre-pit signal of the high power irradiation unit and the low power irradiation unit In the state where the under level of the land pre-pit signal is lower than 0 level, the peak level of the land pre-pit signal of the high power irradiation part and the peak level of the land pre-pit signal of the low power irradiation part are both It matches above level 0.

The width of the slice window for detecting both land pre-pit signals is determined by the peak level of the land pre-pit signal of the high-power irradiation section and the low-power irradiation section and the land pre-pit signal of the low power irradiation section. Since the level difference from the under level is 8.8, and the value of the slice window width = 8.8 is the maximum value that can reliably detect both land prepit signals, a / m1 ≠
The predetermined coefficient k = 1.2 under the condition of b / m2 ≠ L is the theoretical upper limit.

FIG. 11E shows the case where the predetermined coefficient k is set to “1.3”. In this case, the peak level of the land pre-pit signal of the high power irradiation unit and the low power irradiation unit Both the peak level of the land pre-pit signal and the peak level of the land pre-pit signal of the high-power irradiation part were lower than the zero level, and the peak level of the land pre-pit signal of the low-power irradiation part was lower than the zero level. State, the slice window width for detecting both land pre-pit signals, the peak level of the land pre-pit signal of the high power irradiation unit,
The level difference from the under level of the land pre-pit signal of the low power irradiation unit is 7.0, and the value of the slice window width = 7.0 is smaller than that of FIGS. 11C and 11D. Detection of both land pre-pit signals deteriorates.

Accordingly, as shown in FIG. 11 (d), the theoretical upper limit is set when the predetermined coefficient k is "1.2". Since there is no margin in the direction in which the coefficient k becomes larger than 1.2, as shown in FIG. 11C, the predetermined coefficient k is close to “1.1” in terms of reliability and safety. A / m1
It is a practical value under the condition of {b / m2} L.

Here, as shown in FIG. 11D, the condition when the predetermined coefficient k takes the theoretical upper limit under the condition of a / m1 ／ b / m2 ≠ L is as described in (5). Equations and (6)
Equation (7) and Equation (8) below hold.

1.0 <k <α × {(1 + L) / (1-L)} (7) 1.0 <k <α × {(1 + LPPb) / (1-LPPb)} ( In this case, the coefficient α in (Equation 7) and (Equation 8) depends on the performance of the optical pickup 2, the recording power on the basis of the optical pickup 2, and the reproduction power in the reproduction mode. The coefficient α takes a value smaller than 1.0, and the value of the coefficient α may be stored in a memory in advance.

Next, FIG. 12 is a diagram focusing on only the wobbling signal in the radial push-pull signal by removing the land pre-pit signal component by temporarily setting the land pre-pit signal component in the radial push-pull signal to zero. , 0
The positive polarity side of the level indicates the wobbling signal of the high-power irradiation unit and the wobbling signal of the low-power irradiation unit of the (C + D) signal, while the negative polarity side of the 0 level indicates the {-k (A + B)} signal. 5 shows a wobbling signal of a high power irradiation unit and a wobbling signal of a low power irradiation unit.

The {-k (A + B)} signal is simulated by varying the predetermined coefficient k to be multiplied in the same manner as described with reference to FIG. 9, but the predetermined coefficient k = 1 for convenience of illustration. 0, k = 1.1, and k = 1.2 are only shown.

The (C + D) signal indicates the center level of the wobbling signal of the low power irradiation unit as “m1” and the center level of the wobbling signal of the high power irradiation unit as “m”.
2 ", the amplitude on one side above the center level of the wobbling signal of the low power irradiation unit is" c ", and the amplitude on one side above the center level of the wobbling signal of the high power irradiation unit is" d ", and c / m1 = d / When m2 = W, it is the amplitude from the top of the wobbling signal waveform of the high power irradiation section to the top of the wobbling signal waveform of the low power irradiation section (C
+ D) The amplitude WB1 of the signal is calculated by the following (Equation 9).

WB1 = m2−m1 + dc = m2−m1 + W × m2−W × m1 (Equation 9) Similarly to the above, the {−k (A + B)} signal is a wobbling signal of the low power irradiation unit. The center level of
m1 ”, the center level of the wobbling signal of the high-power irradiation unit is“ −km2 ”, the amplitude on one side above the center level of the wobbling signal of the low-power irradiation unit is“ kc ”, and the center level of the wobbling signal of the high-power irradiation unit is The amplitude of one upper side is "kd", and -kc / -km1 = -kd /-
When km2 = W, the amplitude WB2 of the {−k (A + B)} signal, which is the amplitude from the top of the wobbling signal waveform of the low-power irradiation section to the top of the wobbling signal waveform of the high-power irradiation section, is represented by the following equation ( 10).

WB2 = k (m2−m1 + cd) = k (m2−m1 + W × m1−W × m2) (10) The relationship between the above (9) and (10) is also obtained. It will be described later.

Next, FIG. 13 shows that the land pre-pit signal in the radial push-pull signal {(C + D) -k (A + B)} is binarized by the binarization circuit 9 without fail.
+ D) signal and the wobbling signal in the {-k (A + B)} signal, and simulating how the wobbling signal changes by a predetermined coefficient k, thereby obtaining the wobbling signal of the high-power irradiation unit. The theoretical lower limit of the predetermined coefficient k is determined from the relationship between the amplitude of the wobbling signal of the low-power irradiation unit and the amplitude of the low-power irradiation unit.
In FIG. 12, the predetermined coefficient k is "1.
0, "1.1", and "1.2".

First, in the case of FIGS. 13A to 13C,
C / m1 = d / m2 = W as described in FIG.
Is satisfied, and the simulation is performed here with the value of W set to, for example, 0.05.

First, FIG. 13A shows a case where the predetermined coefficient k is set to “1.0”. In this case, the conventional radial push-pull signal ｛(C + D) −
(A + B)}. In this example, the wobbling signal of the high-power irradiation unit and the wobbling signal of the low-power irradiation unit have the same period, and the amplitude of the wobbling signal of the high-power irradiation unit is smaller than that of the low-power irradiation unit. It is larger than the amplitude. This state corresponds to FIG. 10B described above. Although the wobbling signal can be detected well, the detection of the land pre-pit signal cannot be improved.

FIG. 13B shows a case where the predetermined coefficient k is set to “1.1”. In this example, the wobbling signal of the high-power irradiation unit and the wobbling signal of the low-power irradiation unit are different from each other. Although the periods are different, the peak of the waveform of the wobbling signal of the low-power irradiation unit and the peak of the waveform of the wobbling signal of the high-power irradiation unit coincide with each other above the center level, and this state is c / m1 = d
The predetermined coefficient k = 1.1 under the condition of / m2 = W is the theoretical lower limit. This state corresponds to FIG. 10C described above. Although the detection of the wobbling signal is slightly inferior to that of FIG. 13A, the detection of the land pre-pit signal can be detected somehow. The coefficient k = 1.1 is the theoretical lower limit.

FIG. 13C shows a case where the predetermined coefficient k is set to “1.2”. In this example, the lower part of the waveform of the wobbling signal of the low-power irradiator is located below the vertex.
It is located without the vertices of the waveform of the wobbling signal of the high power irradiation part intersecting. This state corresponds to FIG. 10D described above, in which the detection of the wobbling signal is further deteriorated, while the detection of the land pre-pit signal is improved, which has already been described.

Here, as shown in FIG. 13B, when the predetermined coefficient k takes the theoretical lower limit under the condition of c / m1 = d / m2 = W, the condition is as described above. The amplitude WB1 of the wobbling signal in the (C + D) signal according to (Equation 9)
When the amplitude WB2 of the wobbling signal in the {-k (A + B)} signal obtained by the equation (10) has the same value, a theoretical lower limit value of a predetermined coefficient k is obtained. From equation (10), the predetermined coefficient k is a value calculated by the following equation (11).

K = {m2-m1 + W (m2-m1)} / {m2-m1 + W (m1-m2)} = {(m2-m1) (1 + W)} / {(m2-m1) (1-W)} = (1 + W) / (1-W) (Equation 11) Further, W in the above (Equation 11) is a WBLb signal normalized by the above-mentioned (Equation 2) = W1 / R1 = kW2 / kR
2 = W2 / R2, which is clearly equivalent from FIG. 7, so that WB obtained by normalizing the above W value
Lb signal value, that is,
Can be replaced by the following (Equation 12), whereby the output result from the WBLb generation circuit 15 is supplied to the coefficient setting circuit 16, whereby a predetermined coefficient k of the theoretical lower limit is obtained by (Equation 12). .

K = (1 + WBLb) / (1-WBLb) (Equation 12) Although not shown here, the predetermined coefficient k as described in FIG. 12 is c / m1 = d / m2. = W is not satisfied, that is, even in the general case where c / m1 ≠ d / m2 ≠ W, the top of the waveform of the wobbling signal of the low-power irradiation unit is substantially similar to that shown in FIG. When the peak coincides with the peak of the waveform of the wobbling signal of the high-power irradiation section, this state becomes the theoretical lower limit of the predetermined coefficient k under the condition of c / m1 ≠ d / m2 ≠ W. .

In this case, (Expression 13) and (Expression 14), which are pairs with the previously described (Expression 7) and (Expression 8), are established.

1.0 <k <β × {(1 + W) / (1-W)} (13) 1.0 <k <β × {(1 + WBLb) / (1-WBLb)} ((13) (Equation 14) At this time, the coefficient β in (Equation 13) and (Equation 14) depends on the performance of the optical pickup 2, the recording power at the base of the optical pickup 2, and the reproduction power in the reproduction mode. This coefficient takes a value smaller than 1.0, and the value of the coefficient β may be stored in a memory in advance.

Summarizing the above-described details, the predetermined coefficient k is given by (Equation 5), (Equation 6), (Equation 7), and (Equation 8) described above for the land pre-pit signal. (Equation 11), (Equation 12), (Equation 13), and (Equation 14) described above for the wobbling signal.
Are established individually, and these may be applied in combination on the land pre-pit signal side and the wobbling signal.

Therefore, if the predetermined coefficient k is within the range between the theoretical upper limit value and the theoretical lower limit value, the landed prepit signal can be detected accurately and reliably. Expressions (18) to (18) hold.

That is, a / m1 = b / m2 = L and c
Under the condition of / m1 = d / m2 = W, (1 + W) / (1-W) ≦ k ≦ (1 + L) / (1-L) (15) (1 + WBLb) / (1-WBLb) ≦ k ≦ (1 + LPPb) / (1-LPPb) (Equation 16) On the other hand, a / m1 ≠ b / m2 ≠ L and c / m1 ≠ d /
Under the condition of m2 ≠ W, β × {(1 + W) / (1-W)} <k <α × {(1 + L) / (1-L)} (17) β × {(1 + WBLb) ) / (1-WBLb) {<k <α × {(1 + LPPb) / (1-LPPb)} (18) More specifically, the predetermined coefficient k is conventionally set to “1.0”. However, in the present invention, (1) the value of the predetermined coefficient is set to be larger than 1.0 based on the amplitude of the land pre-pit signal or the amplitude of the land pre-pit signal and the amplitude of the wobbling signal. Set the land pre-pit signal by feeding it back to a value within the detectable range,
Or (2) based on the amplitude of the normalized land pre-pit signal, or the amplitude of the normalized land pre-pit signal and the amplitude of the normalized wobbling signal,
By setting the value of the predetermined coefficient to be larger than 1.0 and setting the value of the land pre-pit signal by feedback, the land-pre-pit signal can be detected accurately and reliably. At the time of recording or reproduction of a recording medium, a landed prepit signal corresponding to a landed prepit previously formed on the land 33 can be detected with high accuracy.

Further, in the disk recording / reproducing apparatus of this embodiment, the coefficient setting circuit 16 controls the error rate at the time of detecting the LPP signal, WBL signal, LPPb signal, WBLb signal, land pre-pit signal, and the objective of the optical pickup 2. Based on the shift amount of the lens, the value of the predetermined coefficient k set in the coefficient multiplying circuit 6 is set to a value between the theoretical upper limit and the theoretical lower limit. More specifically, the value of the predetermined coefficient k is set to a value larger than 1.0 and within a range in which a land pre-pit signal can be detected.

As a result, the land pre-pit signal can be detected accurately and irrespective of the high-power irradiating section and the low-power irradiating section on the DVD 31 at the time of recording. In addition, the land pre-pit signal can be accurately and reliably detected regardless of the unrecorded portion.

[0144]

According to the recording and / or reproducing apparatus and method according to the present invention, a groove wobbled at a predetermined frequency and serves as a recording track of an information signal, When recording and / or reproducing information signals on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land pre-pits at a wobbling cycle interval and are alternately formed spirally or concentrically with lands, Return light reflected by irradiating the disk-shaped recording medium with a light beam is received by first and second light-receiving regions at least equally divided along a recording track of the disk-shaped recording medium. One of the light receiving outputs of the light receiving area was multiplied by a predetermined coefficient, and the other light receiving output was multiplied by the predetermined coefficient. The difference obtained by subtracting the output of the result is taken out as a radial push-pull signal, and in detecting a land pre-pit signal corresponding to the land pre-pit from the radial push-pull signal, the predetermined coefficient is conventionally set to “1.0”. However, in the present invention, (1) the amplitude of the land pre-pit signal or
The amplitude of the land pre-pit signal and the amplitude of the wobbling signal, (2) the amplitude of the normalized land pre-pit signal, or the amplitude of the normalized land pre-pit signal and the amplitude of the normalized wobbling signal, Based on (3) the error rate obtained from the radial push-pull signal and (4) the amount of lens shift in the radial direction from the center of the optical axis of the objective lens of the optical pickup, the value of the predetermined coefficient is set to 1.0. Since the land pre-pit signal is set to a value that is larger and can detect the land pre-pit signal, the land pre-pit signal can be recorded regardless of the high-power irradiation part and the low-power irradiation part by the light beam on the disc-shaped recording medium during recording. Can be accurately and reliably detected.
Further, the land pre-pit signal can be accurately and reliably detected at the time of reproduction regardless of the recorded pit formation portion and the unrecorded portion on the disk-shaped recording medium.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the structure of a DVD on which recording and reproduction are performed by a disk recording and / or reproducing apparatus according to an embodiment to which a recording and / or reproducing apparatus and method according to the present invention are applied;

FIG. 2 is a diagram for explaining a format of the DVD.

FIG. 3 is a diagram for explaining a recording position of a land prepit recorded on a land of the DVD.

FIG. 4 is a block diagram of the disk recording / reproducing apparatus of the embodiment.

FIG. 5 is a diagram for explaining divided light receiving areas of light receiving elements provided in the optical pickup of the disk recording / reproducing apparatus of the embodiment.

FIG. 6 is a waveform diagram of a wobbling signal and a land pre-pit signal forming a radial push-pull signal.

FIG. 7 is a waveform diagram of a wobbling signal and a land pre-pit signal for forming a (C + D) signal and a {-k (A + B)} signal for detecting a radial push-pull signal, respectively.

FIG. 8 is a waveform diagram of a (C + D) signal and a {-k (A + B)} signal of a high-power irradiation unit and a low-power irradiation unit.

FIG. 9 is a diagram in which each waveform of a high-power irradiation unit and a low-power irradiation unit of a {-k (A + B)} signal that changes according to a value of a predetermined coefficient k to be multiplied is focused on a land prepit signal. It is.

10 is a diagram showing a high-power irradiating section of a {-k (A + B)} signal that changes according to a value of a predetermined coefficient k to be multiplied when a / m1 = b / m2 = L shown in FIG. 9 is satisfied. FIG. 4 is a diagram showing each waveform of a low-power irradiating section and a land prepit signal.

FIG. 11 shows that when a / m1 ≠ b / m2 ≠ L, {−k (A + B)} changes according to the value of a predetermined coefficient k to be multiplied.
FIG. 5 is a diagram illustrating each waveform of a high-power irradiating portion and a low-power irradiating portion of a signal by focusing on a land prepit signal.

FIG. 12 is a diagram in which each waveform of a high-power irradiation unit and a low-power irradiation unit of a {-k (A + B)} signal, which changes according to a value of a predetermined coefficient k to be multiplied, is viewed focusing on a wobbling signal. .

13 is a diagram illustrating a high-power irradiator of a {-k (A + B)} signal that changes according to a value of a predetermined coefficient k to be multiplied when c / m1 = d / m2 = W shown in FIG. 12 is satisfied. FIG. 6 is a diagram of each waveform of a low-power irradiation unit viewed from a wobbling signal.

[Explanation of symbols]

2: Optical pickup, 3: Preamplifier, 4: (A + B)
Addition circuit, 5 (C + D) addition circuit, 6 coefficient multiplication circuit, 7 RF circuit, 8 RPP generation circuit, 9 binarization circuit, 10 LPP decoding circuit, 11 CPU, 12 ...
LPP amplitude detection circuit, 13... WBL amplitude detection circuit, 14
... LPPb generation circuit, 15 ... WBLb generation circuit, 16 ...
Coefficient setting circuit, 17 ... Lens shift amount detection circuit, 31 ...
DVD, 32 ... wobbling groove, 33 ... land,
34 Land pre-pit

[Procedure amendment]

[Submission date] August 3, 2001 (2001.8.3)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] Fig. 7

[Correction method] Change

[Correction contents]

FIG. 7

[Procedure amendment 2]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 10

Claims (8)

[Claims] A wobbling groove wobbled at a predetermined frequency and serving as a recording track of an information signal;
The recording and / or reproduction of the information signal is performed on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land pre-pits at predetermined wobbling cycle intervals and are alternately formed in a spiral or concentric manner. In the recording and / or reproducing apparatus, when a light beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium. Light is received by the first and second light receiving areas,
Coefficient multiplying means for multiplying one of the light receiving outputs of the light receiving areas by a predetermined coefficient and outputting the result, and the other light receiving output of the light receiving outputs of the first and second light receiving areas A push-pull signal generating means for outputting a difference obtained by subtracting an output of a result of the multiplication processing by the coefficient multiplying means as a radial push-pull signal; and a land pre-pit signal corresponding to a land pre-pit of the land from the radial push-pull signal. And a land pre-pit signal amplitude detecting means for detecting and outputting the amplitude of the land pre-pit signal, and extracting the wobbling signal of the wobbling groove from the radial push-pull signal, and extracting the amplitude of the wobbling signal. Wobbling signal amplitude detection means for detecting and outputting, and the amplitude of the land pre-pit signal, or Coefficient setting means for setting the value of the predetermined coefficient to a value larger than 1.0 and within a range in which the land pre-pit signal can be detected, based on the amplitude of the land pre-pit signal and the amplitude of the wobbling signal. A recording and / or reproducing apparatus characterized by comprising: 2. A wobbling groove which is wobbled at a predetermined frequency and serves as a recording track of an information signal;
The recording and / or reproduction of the information signal is performed on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land pre-pits at predetermined wobbling cycle intervals and are alternately formed in a spiral or concentric manner. In the recording and / or reproducing apparatus, when a light beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium. Light is received by the first and second light receiving areas,
Coefficient multiplying means for multiplying one of the light receiving outputs of the light receiving areas by a predetermined coefficient and outputting the result, and the other light receiving output of the light receiving outputs of the first and second light receiving areas A push-pull signal generating means for outputting a difference obtained by subtracting an output of a result of the multiplication processing by the coefficient multiplying means as a radial push-pull signal; and a land pre-pit signal corresponding to a land pre-pit of the land from the radial push-pull signal. And a land pre-pit signal amplitude detecting means for detecting and outputting the amplitude of the land pre-pit signal, and extracting the wobbling signal of the wobbling groove from the radial push-pull signal, and extracting the amplitude of the wobbling signal. Wobbling signal amplitude detection means for detecting and outputting, and each light receiving output of the first and second light receiving areas Sum signal generating means for taking the sum of the signals and outputting a sum signal; and a normalized land for outputting the normalized amplitude of the land pre-pit signal by dividing the amplitude of the land pre-pit signal by the sum signal. A pre-pit signal amplitude generation unit; a normalized wobbling signal amplitude generation unit that outputs a normalized wobbling signal amplitude by dividing the amplitude of the wobbling signal by the sum signal; Pre-pit signal amplitude, or
Based on the normalized amplitude of the land pre-pit signal and the amplitude of the normalized wobbling signal, the value of the predetermined coefficient is set to a value larger than 1.0 and within a range in which the land pre-pit signal can be detected. A recording and / or reproducing apparatus comprising: a coefficient setting means for setting a value. 3. A wobbling groove which is wobbled at a predetermined frequency and serves as a recording track of an information signal.
The recording and / or reproduction of the information signal is performed on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land pre-pits at predetermined wobbling cycle intervals and are alternately formed in a spiral or concentric manner. In the recording and / or reproducing apparatus, when a light beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium. Light is received by the first and second light receiving areas,
Coefficient multiplying means for multiplying one of the light receiving outputs of the light receiving areas by a predetermined coefficient and outputting the result, and the other light receiving output of the light receiving outputs of the first and second light receiving areas A push-pull signal generating means for outputting a difference obtained by subtracting the output of the result of the multiplication processing by the coefficient multiplying means as a radial push-pull signal; and an error rate upon detection of a land pre-pit signal included in the radial push-pull signal. Error rate calculating means for calculating and outputting the coefficient, and coefficient setting for setting the value of the predetermined coefficient to a value larger than 1.0 and within a range in which the land pre-pit signal can be detected based on the error rate. Means for recording and / or reproducing. 4. A wobbling groove which is wobbled at a predetermined frequency and serves as a recording track of an information signal.
The recording and / or reproduction of the information signal is performed on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land pre-pits at predetermined wobbling cycle intervals and are alternately formed in a spiral or concentric manner. In the recording and / or reproducing apparatus, when a light beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium. Light is received by the first and second light receiving areas,
Coefficient multiplying means for multiplying one of the light receiving outputs of the light receiving areas by a predetermined coefficient and outputting the result, and the other light receiving output of the light receiving outputs of the first and second light receiving areas A push-pull signal generating means for outputting a difference obtained by subtracting an output of a result of the multiplication processing by the coefficient multiplying means as a radial push-pull signal; and light from an objective lens of an optical pickup for irradiating the light beam to the disc-shaped recording medium. A lens shift amount detecting unit that detects a lens shift amount in a radial direction from the axis center and outputs the lens shift amount; and, based on the lens shift amount, sets the value of the predetermined coefficient to be greater than 1.0 and A recording and / or reproducing apparatus comprising: a coefficient setting means for setting a land pre-pit signal to a value within a detectable range. 5. A wobbling groove which is wobbled at a predetermined frequency and serves as a recording track of an information signal;
The recording and / or reproduction of the information signal is performed on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land pre-pits at predetermined wobbling cycle intervals and are alternately formed in a spiral or concentric manner. In the recording and / or reproducing method, when a light beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium. Light is received by the first and second light receiving areas,
A coefficient multiplying step of multiplying one of the light receiving outputs of the light receiving areas by a predetermined coefficient and outputting the result, and the other light receiving output of the light receiving outputs of the first and second light receiving areas A push-pull signal generating step of outputting a difference obtained by subtracting an output of a result of the multiplication processing in the coefficient multiplying step as a radial push-pull signal; and a land pre-pit signal corresponding to a land pre-pit of the land from the radial push-pull signal. And a land pre-pit signal amplitude detection step of detecting and outputting the amplitude of the land pre-pit signal, and extracting the wobbling signal of the wobbling groove from the radial push-pull signal, and calculating the amplitude of the wobbling signal. Detecting a wobbling signal amplitude to be detected and output; The predetermined coefficient value is larger than 1.0 and is within a range in which the land pre-pit signal can be detected based on the amplitude of the preset signal or the amplitude of the land pre-pit signal and the amplitude of the wobbling signal. A coefficient setting step of setting a value to a value. 6. A wobbling groove which is wobbled at a predetermined frequency and serves as a recording track of an information signal;
The recording and / or reproduction of the information signal is performed on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land pre-pits at predetermined wobbling cycle intervals and are alternately formed in a spiral or concentric manner. In the recording and / or reproducing method, when a light beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium. Light is received by the first and second light receiving areas,
A coefficient multiplying step of multiplying one of the light receiving outputs of the light receiving areas by a predetermined coefficient and outputting the result, and the other light receiving output of the light receiving outputs of the first and second light receiving areas A push-pull signal generating step of outputting a difference obtained by subtracting an output of a result of the multiplication processing in the coefficient multiplying step as a radial push-pull signal; and a land pre-pit signal corresponding to a land pre-pit of the land from the radial push-pull signal. And a land pre-pit signal amplitude detection step of detecting and outputting the amplitude of the land pre-pit signal, and extracting the wobbling signal of the wobbling groove from the radial push-pull signal, and calculating the amplitude of the wobbling signal. A wobbling signal amplitude detection step of detecting and outputting the first and second wobbling signal amplitudes; A sum signal generating step of taking the sum of the respective light receiving outputs of the light receiving region and outputting a sum signal; and dividing the amplitude of the land prepit signal by the sum signal to obtain a normalized amplitude of the land prepit signal. A normalized wobbling signal amplitude generating step of outputting a normalized wobbling signal amplitude by dividing the amplitude of the wobbling signal by the sum signal; The amplitude of the normalized land pre-pit signal, or
Based on the normalized amplitude of the land pre-pit signal and the amplitude of the normalized wobbling signal, the value of the predetermined coefficient is set to a value larger than 1.0 and within a range in which the land pre-pit signal can be detected. A coefficient setting step of setting a value to a value. 7. A wobbling groove wobbled at a predetermined frequency and serving as a recording track of an information signal;
The recording and / or reproduction of the information signal is performed on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land pre-pits at predetermined wobbling cycle intervals and are alternately formed in a spiral or concentric manner. In the recording and / or reproducing method, when a light beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium. Light is received by the first and second light receiving areas,
A coefficient multiplying step of multiplying one of the light receiving outputs of the light receiving areas by a predetermined coefficient and outputting the result, and the other light receiving output of the light receiving outputs of the first and second light receiving areas A push-pull signal generating step of outputting a difference obtained by subtracting an output of a result of the multiplication processing in the coefficient multiplying step as a radial push-pull signal; and an error rate upon detection of a land pre-pit signal included in the radial push-pull signal. An error rate calculating step of calculating and outputting, based on the error rate, a coefficient setting for setting the value of the predetermined coefficient to a value larger than 1.0 and within a range in which the land pre-pit signal can be detected Recording and / or reproducing method. 8. A wobbling groove wobbled at a predetermined frequency and serving as a recording track of an information signal;
The recording and / or reproduction of the information signal is performed on a disk-shaped recording medium in which at least address information and the like are preliminarily recorded as land pre-pits at predetermined wobbling cycle intervals and are alternately formed in a spiral or concentric manner. In the recording and / or reproducing method, when a light beam is applied to the disc-shaped recording medium, reflected light from the disc-shaped recording medium is divided into at least two equal parts along the recording tracks of the disc-shaped recording medium. Light is received by the first and second light receiving areas,
A coefficient multiplying step of multiplying one of the light receiving outputs of the light receiving areas by a predetermined coefficient and outputting the result, and the other light receiving output of the light receiving outputs of the first and second light receiving areas A push-pull signal generating step of outputting a difference obtained by subtracting an output of a result of the multiplication processing in the coefficient multiplying step as a radial push-pull signal; and a light of an objective lens of an optical pickup for irradiating the light beam to the disc-shaped recording medium. A lens shift amount detecting step of detecting a lens shift amount in the radial direction from the axis center and outputting the lens shift amount; and setting the value of the predetermined coefficient to be greater than 1.0 and A coefficient setting step of setting a land pre-pit signal to a value within a detectable range.