JP2002324325A - Optical disk drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the land prepit on both sides of the groove without fail. SOLUTION: The track of the optical disk 1 consists of a wobbled groove 3 and lands 4 located between the adjacent grooves 3 both made into a pair. Address information to the information signals on a groove 3 is formed in advance as the land prepit 5 on the land 4. The grooves are scanned with a light beam spot B and the light reflected on the disk 1 is received by a photo-detector PD which has a light-receiving area divided at least into two, the first and second 2nd light-receiving areas, in the direction of the tracks. When detecting the land prepit 5 in junction with the groove 3 from the radial push- pull signal which is the difference signal of the outputs of the 1st and the 2nd light-receiving areas, the land prepits 5 close to the hill of the wave on the groove 3 and the land prepits 5 close to the dale of the wave on the groove 3 are each detected from the radial push-pull signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a track comprising a pair of wobbled grooves on both sides and lands located between adjacent grooves extending from the innermost circumference to the outermost circumference on a disk substrate. Using an optical disk which is formed in a spiral or concentric shape and on which land information such as address information for an information signal to be recorded in the groove is preliminarily formed as land prepits, each land preform formed on both sides of the groove is used. The present invention relates to an optical disk device configured to reliably reproduce pits.

[0002]

2. Description of the Related Art Generally, a CD (Compact Di) is used.
sc), DVD (Digital Versatile)
An optical disc such as a disc) can record and / or reproduce information signals such as video information, audio information, and computer data on a spirally or concentrically formed track on a disc-shaped disc substrate at a high density. They are often used because they allow fast access to trucks.

On the other hand, an optical disk and an optical disk recording / reproducing apparatus capable of recording / reproducing information signals at a higher density are required, and various improvements have been made to satisfy this requirement. A method of reducing the track width and track pitch to increase the density of information signals has been adopted. Accordingly, in order to accurately read address information and accurately control the rotation of the optical disk even with a narrow track width and a narrow track pitch, a wobble groove (groove) and a land located between adjacent grooves are used. The paired tracks are formed spirally or concentrically from the innermost circumference to the outermost circumference on the disk substrate, and auxiliary information to the information signal to be recorded in the groove is previously provided on the land as land prepits. An optical disk formed and an optical disk recording / reproducing apparatus for recording / reproducing the optical disk are disclosed in, for example,
It is disclosed in, for example, JP-A-326138 and JP-A-10-293926.

FIGS. 16A and 16B are views for explaining an example of a conventional optical disk. FIG. 16A shows a track in which a wobbled groove and a land located between adjacent grooves are paired, and FIG. FIG. 17 is a diagram showing pulses by land pre-pits on the peripheral side and the outer peripheral side, and FIG. 17 is a view for explaining another example of the conventional optical disk.

[0005] First, in the optical recording medium, recording and reproducing method and recording and reproducing apparatus disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 9-326138, a CLV (Constant Line) is used.
arVelocity (constant linear velocity) is intended for high-density recording and reproduction of information signals using an optical disk of a rotation control system, and as shown in FIG.
Is a groove 101 wobbled at a single frequency.
And lands 102 formed between the adjacent grooves 101 are formed in a spiral shape on a disk substrate (not shown).

At this time, the groove 101 has a width of about 0.25 μm.
m, a depth of about 70 nm, and a track pitch of 0.74 μm. Also, the groove 101 and the groove 101
Land pre-pits 103 (previously described as address pits) in which address information is recorded in advance are formed at predetermined intervals on lands 102 formed between them. Is about 0.3 width
Grooves having the same thickness as the groove 101 and having a depth of about 70 nm are formed so as to extend between the adjacent grooves 101.

In the recording / reproducing method and the recording / reproducing apparatus for recording / reproducing the optical disk 100, one groove 101 on the optical disk 100 and a land 102 adjacent thereto are irradiated with a beam spot B to irradiate the groove 101.
In addition to controlling the rotation of the optical disc 100 by the wobble signal detected from, the address information on the optical disc 100 is read by the pulse detected from the land pre-pit 103 on the land 102.

At this time, as shown in FIG. 16B, when the beam spot B is scanned along the groove 101, the land 1 on the inner peripheral side with respect to the groove 101 being scanned.
2 and a pulse on the outer peripheral land 102 formed on the outer land 102 with respect to the groove 101 being scanned and having a polarity opposite to that of the inner peripheral side. Although a pulse due to the pre-pit 103 is obtained, one of the land pre-pits 10
3, the address information is detected based on the pulse. At this time, the same publication discloses a specific description of obtaining a pulse by binarizing a signal from the land pre-pit 103 when obtaining a pulse from the inner or outer land pre-pit 103. Absent.

Since the land pre-pit 103 formed on the land 102 is formed so as to straddle the groove 101, the land pre-pit 103 on the outer peripheral side with respect to the groove 101 being scanned by the beam spot B is used. If the pre-pit 103 indicates the address information of the groove 101 currently being scanned, the land pre-pit 103 on the inner circumference side is the groove on the inner circumference side one track before the groove 101 currently being scanned. It shows address information for the address 101.

Next, the above-mentioned Japanese Patent Application Laid-Open No. 10-293926 is described.
In the recording clock signal generation device disclosed in
CD-R (CD-Recordable) as an optical disc
e) DVD-R with increased recording capacity about 7 times
(DVD-Recordable), which is also aimed at high-density recording / reproduction of information signals.
As schematically shown in FIG. 1, an optical disc 200 has a groove track 201 wobbled with a wobble signal of a predetermined frequency component and a land track 202 formed between adjacent groove tracks 201 in a spiral shape on a disc substrate (not shown). Alternatively, land prepits 203 formed concentrically and having a predetermined phase relationship with the wobble signal on the land track 202 are formed in advance. Further, since the optical disc 200 is applied to a DVD-R, a groove track 201 for recording an information signal is divided in advance for each sync frame as an information unit. One recording sector is composed of 26 sync frames, and one ECC (Error Corre) is composed of 16 recording sectors.
cting Code) block. One sync frame is 1488 times (148) a unit length (hereinafter, referred to as T) corresponding to a pit interval defined by a recording format for recording an information signal.
8T), and the first 14T portion of one sync frame is used as synchronization information SY for synchronizing each sync frame.

On the other hand, land pre-pits 203 recorded on the land track 202 of the optical disk (DVD-R) 200 are recorded for each sync frame. At this time, one land pre-pit 203 is always formed on the land track 202 adjacent to the area where the synchronization information SY is recorded in each sync frame as a signal indicating the synchronization signal in the pre-information. Information S
One or two land pre-pits 203 indicating the contents of pre-information to be recorded are placed on the land track 202 adjacent to the first half of the sync frame other than Y.
(Note that the land pre-pit 203 may not be formed in the first half of the sync frame other than the synchronization information SY depending on the content of the pre-information to be recorded.) Further, in one recording sector, land pre-pits 203 are formed in either one of the even-numbered sync frame (EVEN frame) and the odd-numbered sync frame (ODD frame) to record pre-information. It is set according to the content of the information.

In the recording clock signal generator described above, the signal carrying the phase of the wobble signal extracted from the wobbled groove track 201 and the land pre-pit signal detected from the land pre-pit 203 on the land track 202 are used. By comparing the phase and outputting a phase difference signal, and adjusting the phase of the clock signal based on the phase difference signal, the influence of crosstalk on the time axis of the clock signal generated based on the wobble signal that cannot be ignored Is corrected by using the land pre-pits 203 which are not affected by crosstalk.
It is possible to generate a recording clock signal synchronized with the rotation of 0 with high accuracy.

[0013]

By the way, in the above-mentioned conventional optical disk and the optical disk recording / reproducing apparatus to which the conventional optical disk is applied, when increasing the density of the information signal, the optical disk is formed on the optical disks 100 and 200, respectively. Grooves 101, 201 and land pre-pits 103, 2
And development of ultra-high-density optical discs having a recording capacity of about 20 gigabytes in order to further increase the density of information signals, even though the lands 102 and 202 each having a track 03 are narrowed. Is being actively conducted. In such an ultra-high-density optical disk, the track pitch can be further narrowed by setting the track pitch to, for example, 1/2 or less of the track pitch of 0.74 μm in the above-described example optical disk 100. Become.

In such an ultra-high density optical disk under development, land pre-pits indicating address information and the like are formed in advance on the land, and when address information and the like are detected from the land pre-pits, a further improvement is required. Due to the narrowing of the track, the output of the land pre-pits becomes small, and there may be a case where address information and the like cannot be reliably obtained from the land pre-pits.

On the other hand, JP-A-9-32 described in the prior art
In the optical disc 100 disclosed in Japanese Patent No. 6138, as described above with reference to FIG.
When the beam spot B is scanned along the line 01, the address information is determined based on one of the pulse by the land prepit 103 on the inner circumference side and the pulse by the land prepit 103 on the outer circumference side. In this case, since the track pitch is still wide for the ultra-high density optical disc under development, the land pre-pits 103 can be formed on the lands 103 in a wide and reliable manner. The address information and the like can be reliably detected by detecting the land pre-pit 103 on one side.

However, in the ultra-high-density optical disk under development, since the track spacing is physically narrow, the reliability is low only on one side of the land pre-pits on the inner circumference or the outer circumference. By detecting the land pre-pits on the side and the outer side, when one cannot be read, the other can make up for it, so although the reliability can be improved,
In this case, the waveform of the groove wobbled at a single frequency or at a predetermined frequency is a sine having peaks and troughs repeated.
Because it is formed by a curve or a cosine curve,
For example, a land pre-pit connected to the peak of the groove waveform is set to the outer circumference (or inner circumference), while a land pre-pit connected to the trough of the groove waveform is set to the inner circumference (or outer circumference). When the land pre-pits are binarized, the detection accuracy differs between the land pre-pits on the mountain side (outer side) and the land pre-pits on the valley side (inner side) for one slice level (threshold). Finally, especially
The land prepits on the valley side (inner circumference side) are hard to detect because they are in the valley of the groove waveform, and the land prepits on the valley side (outer circumference side) and the valley side (inner circumference side) can be read with the same detection accuracy. There is a problem that it cannot be done.

Furthermore, the conventional optical discs 100 and 200
Since the grooves 101 and 201 formed above are wobbled at a single frequency or a predetermined frequency, both optical discs 100 and 200 record and reproduce information signals while their rotations are controlled at CLV (constant linear velocity). , The following problems are described, and these problems will be described with reference to FIG.

FIG. 18 shows a conventional optical disk.
(A) schematically shows a location where the wobble phase of the wobbled groove has the opposite phase, and (b) schematically shows a location where land prepits formed on lands adjacent to both sides of one groove overlap each other. FIG.

The conventional problems will be described in the order of items. Since both the conventional optical discs 100 and 200 are rotationally controlled at CLV (constant linear velocity), there are places where the wobble phases of adjacent grooves in the radial direction of the disc become opposite phases, and crosstalk from an adjacent track becomes large. That is, there are a plurality of areas on the optical disk surface that cannot be used for recording due to deterioration of signal quality. In addition, since the phase is reversed, the land pre-pit signal may be deteriorated.

More specifically, as shown in FIG. 18A, three grooves 101 adjacent in the radial direction of the disk are provided.
In (201), the phase of the wobbles formed in the middle groove 101 (201) and the groove 101 (201) in the upper part of the figure may be reversed as surrounded by a dotted line. In such a case, in a portion surrounded by a dotted line, a crosstalk from an information signal recorded in a portion where a distance between the groove 101 and the adjacent groove 101 (201) is narrowed increases, a data error occurs due to signal deterioration, or a time when recording is performed. Erroneous erasure of an adjacent track already recorded occurs.

As shown in FIG. 18B, as the wobble phase gradually shifts between the adjacent grooves 101 (201), one groove 101 (201) is shifted.
Since the relative positions of the land pre-pits 103 (203) on the lands 102 (202) adjacent to both sides of the
On both sides of one groove 101 (201), there are places where the land prepits 103 (203) of the parts surrounded by the dotted line overlap each other. In such a region surrounded by the dotted line, the output of the land prepit signal detected from the land prepit 103 (203) is not sufficiently obtained, which affects the reading of the land prepit signal.

For this reason, as described above, in the portion where the wobble phases are opposite to each other between the adjacent grooves 101 (201), the digital information signal is not recorded or the land pre-pit 103 (203) is Measures such as not recording were required.

[0023] Also, one groove 101 (20
If the land pre-pits 103 (203) on the adjacent lands 102 (202) on both sides of 1) overlap each other, the information signal cannot be reproduced at this point, so the land pre-pits 103 (203) It is necessary to perform processing such as changing the position of.

Therefore, an optical disk device capable of solving the above-mentioned problems has been desired.

[0025]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first invention is to provide a groove having wobbles on both sides and a land located between the adjacent grooves. The paired tracks are formed spirally or concentrically on the disk substrate, and on the lands, address information and the like to information signals to be recorded in the grooves are formed in advance as land pre-pits, and One side of the land prepit is connected to the crest of the waveform of the groove on one side of the groove, and the other is connected to the bottom of the waveform of the groove so that the two do not coincide with each other while maintaining a predetermined interval. Using an optical disc formed shifted, the reflected light from the optical disc is tracked while scanning the groove on the optical disc with a beam spot. First, received by photo-detector having a second light receiving regions divided into at least two along,
An optical disc device configured to detect the land pre-pits connected to the groove from a radial push-pull signal based on a difference signal between outputs of the first and second light receiving regions, wherein the land pre-pit is connected to the groove from the radial push-pull signal. The land pre-pits connected to the crest side of the waveform and the land pre-pits connected to the trough side of the groove waveform are respectively detected, and each land pre-pit signal by each land pre-pit is binarized. An optical disc device characterized by the following.

According to a second aspect of the present invention, a track is formed in a spiral or concentric manner on a disk substrate, with a pair of grooves wobbled (meandering) on both sides and lands located between adjacent grooves. In addition, address information and the like to information signals to be recorded in the groove are previously formed on the land as land prepits, and the land prepits are located on both sides of the groove, one on the mountain side of the waveform of the groove. Using an optical disc formed by connecting the other side to the valley side of the waveform of the groove and displacing the positions so that they do not coincide with each other while maintaining a predetermined interval, and the beam spot on the optical disc is used. It has first and second light receiving regions obtained by dividing the reflected light from the optical disk at least into two along the track direction while scanning the groove. An optical disc device configured to receive light by a photodetector and detect the land prepit connected to the groove from a radial push-pull signal based on a difference signal between outputs of the first and second light receiving areas, Wobble signal extraction means for extracting the wobble signal of the groove from the radial push-pull signal, and detecting the land prepit connected to the crest side of the waveform of the groove, the wobble signal extraction means for extracting the wobble signal of the groove extracted by the wobble signal extraction means. Adding means for adding a first DC bias voltage to a wobble signal to set a first slice level at the time of binarizing the land prepit signal into a land prepit signal by the land prepit on the mountain side, and a valley side of the groove waveform When detecting the land pre-pits connected to the wobble signal extraction means, Subtraction means for subtracting a second DC bias voltage from the wobble signal of the groove to set a second slice level when binarizing the land prepit signal by the land prepit on the valley side; A first LPP binarization unit for binarizing the land prepit signal on the mountain side based on the first slice level set by the addition unit with respect to the pull signal; and a subtraction unit with respect to the radial push-pull signal. A second LP for binarizing the land prepit signal on the valley side based on the set second slice level;
An optical disc device comprising P2 binarizing means.

According to a third aspect of the present invention, in the optical disk device of the second aspect, the wobble signal extracting means is adapted to detect the radial push-pull signal when the land pre-pit signal on the mountain side and the valley side does not exist. An optical disk device wherein the wobble signal is extracted by masking (holding) both land pre-pit signals during a period in which the land pre-pit signals on the mountain side and the valley side are present. is there.

The fourth aspect of the present invention is directed to the first to third aspects.
In the optical disk device according to any one of the inventions, when generating the radial push-pull signal, the optical detector may be configured to output one of the outputs of the first and second light receiving regions of the photodetector. A first radial push-pull signal for detecting the land pre-pit signal on the peak side by a difference signal between one output multiplied by each coefficient and the other output not multiplied by each coefficient; And a second radial push-pull signal for detecting the land pre-pit signal on the side.

According to a fifth aspect of the present invention, a track having a pair of wobbled grooves on both sides and a land located between adjacent grooves is formed in a spiral or concentric shape on the disk substrate. In addition, address information and the like to information signals to be recorded in the groove are previously formed on the land as land prepits, and the land prepits are located on both sides of the groove, one on the mountain side of the waveform of the groove. Using an optical disc formed by connecting the other side to the valley side of the waveform of the groove and displacing the positions so that they do not coincide with each other while maintaining a predetermined interval, and the beam spot on the optical disc is used. It has first and second light receiving regions obtained by dividing the reflected light from the optical disk at least into two along the track direction while scanning the groove. An optical disc device configured to receive light by a photodetector and detect the land prepit connected to the groove from a radial push-pull signal based on a difference signal between outputs of the first and second light receiving areas, Wobble signal extraction means for extracting a wobble signal of the groove from a radial push-pull signal; and detecting the land prepit connected to the valley side of the waveform of the groove, the groove extracted by the wobble signal extraction means. Subtracting means for subtracting a DC bias voltage from the wobble signal to set a slice level when binarizing the land prepit signal into a land prepit signal on the valley side; The land pre-pit signal on the valley side based on the slice level set by the subtraction means. Binarizes the LP
An optical disc device comprising P2 binarizing means.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disk apparatus according to the present invention will be described below in detail in the order of items with reference to FIGS.

Before describing the optical disk device according to the present invention, an optical disk applied to the optical disk device will be described first.

<Optical Disk> FIG. 1 is a perspective view for explaining an optical disk applied to the optical disk apparatus according to the present invention, FIG. 2 is a plan view showing the configuration of zones in the optical disk shown in FIG. FIG. 3 is a diagram schematically showing a wobble cycle of a wobbled groove divided into an inner circumference side and an outer circumference side in the optical disc shown in FIGS. 1 and 2.

As shown in FIG. 1, an optical disk 1 applied to an optical disk apparatus according to the present invention is formed by forming a transparent disk substrate 2 having a thickness of, for example, about 0.6 mm in a disk shape. A groove 3 wobbled in a sine curve or a cosine curve shape on one surface side of the groove 3 and a land 4 located between adjacent grooves 3
Are formed spirally or concentrically from the innermost circumference to the outermost circumference on the disk substrate 2, and on the lands 4, address information for information signals to be recorded on the grooves 3, etc. Are formed in advance as land pre-pits 5.

The shapes of the groove 3 and the land 4 are generally such that the groove 3 is formed in a concave shape and the land 4 is formed in a convex shape. In order for the relationship between the concavities and convexities to be reversed, one of the concave and convex shapes of the groove 3 and the land 4 may be formed in a concave shape and the other may be formed in a convex shape.

Further, as will be described later, recording block units (ECC blocks) for information signals are allocated corresponding to a predetermined number of land pre-pits 5.

At this time, the groove 3 is a recording track for recording an information signal. On the other hand, the land pre-pits 5 formed on the lands 4 are composed of auxiliary information such as address information, correction parities, etc. in pit form. Is recorded in advance.

On the groove 3 and the land 4, a phase change recording layer 6 using a phase change material, a metal reflection layer 7 using Al (aluminum), Au (gold), and the like, and a protective layer 8 Are sequentially formed, and a reinforcing substrate 9 having a thickness of about 0.6 mm is attached to the protective layer 8 side by using an adhesive to form the optical disc 1 having a total thickness of 1.2 mm.

Therefore, the optical disc 1 can be overwritten with information signals and additionally recorded with information signals by the phase-change recording layer 6 formed on the groove 3, and can be applied to an ultra-high-density optical disc under development. ing.

Then, a beam spot B is applied to one groove 3 from the other surface side of the transparent disk substrate 2 and lands 4 and 4 adjacent to both sides of the groove 3.
The returning reflected light of the beam spot B reflected by the metal reflection layer 7 through the disk substrate 2 and the phase change recording layer 6 is used as an optical disk recording / reproducing apparatus 20A (FIG. 9) or a second embodiment of the first embodiment to be described later. Example optical disk recording / reproducing device 20B
(FIG. 15) A four-division photo detector PD (FIGS. 9 to 11, FIG.
The reproduced signal is detected by the push-pull method using 5).

Incidentally, if it is necessary to reduce the thickness of the disk substrate located on the information signal reading side in order to further improve the recording density on the optical disk 1, though not shown, the thickness is reduced to 0. Tracks having pairs of grooves 3 and lands 4 are formed spirally or concentrically on a thick disk substrate 2 having a thickness of about 0.5 mm to 1.1 mm.
After the metal reflection layer 7 and the phase change recording layer 6 are sequentially formed on the lands 4, the thickness of the metal reflection layer 7 and the phase change
There is also a method in which a thin transparent film of about 0.2 mm is adhered with a transparent adhesive, and the optical disc 1 is formed so that the beam spot B is irradiated from the thin transparent film side.

As shown in FIG. 2, in the optical disc 1 according to the present invention, a plurality of recording areas for recording information signals are formed concentrically around the center hole 2a of the disc substrate 2 along the radial direction of the optical disc 1. Is divided into zones. At this time, as an example, the diameter of the optical disc 1 is set to 12c.
m and the recording area is changed from zone 0 to zone N-
When divided into N pieces up to 1, the number of zones N is, for example, 83, and each zone is composed of, for example, 1024 tracks.

The rotation control method for the optical disc 1 is as follows.
ZCLV (Zone Constant) in which the rotation speed of the optical disc 1 is sequentially switched stepwise from zone 0 to zone N-1 for each zone and the rotation is controlled to be substantially constant in linear velocity.
A Linear Constant Angular (ZCAV) system in which the rotation speed is constantly controlled at a constant rotation speed set for each zone by a ZCLV in each zone while a linear velocity (ZVV) method is employed.
r Velocity) method is employed.

As shown in FIG. 3, the rotation speed of the optical disk 1 is sequentially changed stepwise for each zone by the ZCLV system in accordance with the rotation control method for the optical disk 1 described above. Is high, the rotation speed on the outer circumference side is set low, and the wavelength of the wobble of the groove 3 is shorter on the inner circumference side and longer on the outer circumference side in the same zone.

In each zone, the 1024 grooves 3 are rotated at a constant rotation speed by the ZCAV system, so that the phases of the wobbles are all formed in the same phase. Since the phenomena such as the phases of the grooves 3 being opposite to each other do not occur, the crosstalk from the adjacent track caused by the narrow interval between the grooves 3 does not occur.

The land prepits 5 formed on the lands 4 are connected so as to straddle the grooves 3 wobbled in a sine curve or a cosine curve. When the land pre-pit 5a connected to the peak side of the groove 3 is set to the outer side (or the inner side) and the land pre-pit 5b connected to the valley side of the waveform of the groove 3 is set to the inner side (or the outer side), As described in the conventional example, when scanning while tracking one groove 3 with the beam spot B, the land pre-pits 5a on the outer peripheral side with respect to one groove 3 being scanned.
Indicates the address information of the groove 3 currently being scanned, on the other hand, the land pre-pit 5b on the inner circumference side has the address for the groove 3 on the inner circumference side one track before the groove 3 currently being scanned. Since the information indicates information, the present invention detects the land pre-pits 5a on the outer circumference side and the land pre-pits 5b on the inner circumference side. Even if the address information of the groove 3 being scanned by B cannot be read, the address information of the groove 3 being scanned by the beam spot B can be obtained by detecting the land pre-pits 5b on the inner peripheral side. Even if the track is narrowed in accordance with the increase in the recording density, the detection accuracy of the land pre-pits 5 can be improved. Pits 5a, will be described later method of detecting 5b.

Next, a description will be given of the land pre-pits 5 formed on the lands 4 in one appropriate zone on the optical disk 1 with reference to FIGS.

FIGS. 4A and 4B are views for explaining land prepits formed on lands in an optical disk applied to the optical disk apparatus according to the present invention. FIG. 4A schematically shows the shape of land prepits. FIG. 5B is a diagram showing a waveform of a land pre-pit signal when a land pre-pit is detected, FIG. 5 is a diagram showing a signal form in a groove synchronization frame, and FIG. FIG. 7 is a diagram for explaining the types of the formed land prepits, FIG. 7 is a diagram showing a plurality of land prepits provided corresponding to one sector, and FIG. 8A is a diagram showing one land prepit in one ECC block. FIG. 3B shows land prepit blocks of a sector, and FIG. 4B shows a land prepit block corresponding to one ECC block.

As shown in FIG. 4A, in one appropriate zone on the optical disk 1, a plurality of grooves 3 are wobbled along the disk circumferential direction at the same phase. One of three synchronization frame periods is set to, for example, three wobble periods.

When one beam 3 is scanned while being tracked by the beam spot B, the hill side (outer circumference side) and the valley side (inner circumference) formed on the lands 4 and 4 located on both sides of one groove 3 respectively. The land pre-pit signals detected from the reproduced signals by the push-pull method using the four-part type photodetector PD (FIGS. 9 to 10 and FIG. 15) are the land pre-pit signals 5a and 5b of FIG.
As shown in (b), the polarity is reproduced in the opposite direction every synchronization frame period. At this time, in the detection of the land pre-pit signal by the push-pull method, the land pre-pit signal by the land pre-pit 5a on the mountain side (outer side) becomes a positive output, while the land pre-pit on the valley side (inner side) is output. The land pre-pit signal 5b is a negative output.

As shown in FIG. 5, a synchronization signal SY and an information signal D are recorded in one synchronization frame corresponding to one synchronization frame period of the groove 3.

The data format of the information signal recorded in the groove 3 is one sector (recording sector) with 26 synchronization frames (in sync frames) as described in the DVD-R of the prior art. However, in this embodiment, one ECC (Err
or Correcting Code) block is D
It is composed of 32 sectors, twice the VD-R.

Returning to FIG. 4A, land prepits 5 formed on the lands 4 between the grooves 3 are provided corresponding to the wobble period and the synchronization frame period of the groove 3.

More specifically, the land pre-pits 5
Each land pre-pit 5 is provided at a predetermined position with respect to the wobble period and the synchronization frame period, and is provided at every other position as a predetermined interval with respect to one synchronization frame period of the groove 3. One of the land prepits 5a, 5b formed on the lands 4, 4 located on both sides of one groove 3 is connected to the peak of the waveform of the groove 3, and the other is connected to the valley of the waveform of the groove 3. They are provided so that they do not overlap with each other so that they do not coincide with each other while maintaining a predetermined interval.

That is, land pre-pits 5a formed on one land 4 for one groove 3 are provided corresponding to odd-numbered synchronous frames, and land pre-pits 5a formed on land 4 on the other side. Since the pre-pits 5b are provided corresponding to the even-numbered synchronization frames, the land pre-pits 5a and 5b do not overlap each other on both sides of one groove 3.

In the land pre-pit 5, as shown in FIG. 6, four types of code data are set by a combination using three bits (b2, b1, b0).
An array of 3 bits (b2, b1, b0) is set at a predetermined position of each of the wobbles synchronized with the wobble cycle in three consecutive wobbles in total.

At this time, the arrangement of the three bits (b2, b1, b0) of the land pre-pit 5 corresponds to the pre-pit synchronization signal 1
Is (1,1,1), and the pre-pit synchronization signal 2 is (1,1,1).
(1, 0), the pre-pit data is set to (1, 0, 1), and the pre-pit data = 0 is set to (1, 0, 0).

Therefore, each land pre-pit 5 is always provided with one of the four types, and
Bit b2 is set to “1” in common for the types of land prepits 5, and both bits b1 of the prepit synchronization signal 1 and prepit synchronization signal 2 are “1”.
By recognizing that the bit b0 is "1" or "0", it can be handled as 1-bit data.

Accordingly, as described above, since one sector is composed of 26 synchronization frames, every other land pre-pit 5 is provided for every synchronization frame period of the synchronization frame. Thirteen sectors are provided corresponding to one sector, and are arranged as shown in FIG.

As shown in FIG. 8A, one E
The CC block is composed of 32 sectors, and 13 land prepits 5 provided corresponding to each sector are composed of one prepit synchronization signal (1 or 2) and 12 prepit data (12 bits). ).

Further, the land pre-pit block shown in FIG. 8B combines the land pre-pits 5 provided in one sector shown in FIG. 8A for 32 sectors into one ECC block. It is made to correspond.

Here, the contents to be recorded in the land prepit for one sector include a prepit synchronization signal, a relative sector address in the block, and disk information such as an ECC block address and a zone number. At this time, since 8 bits are allocated to the disc information, the remaining 5 bits must indicate the pre-pit synchronization signal and the relative sector address. But,
To represent the address of 32 sectors in one ECC block, all 5 bits are required. Therefore, the pre-pit synchronization signal is 1 bit, the relative sector address is 4 bits, and the pre-pit synchronization signal uses two code patterns of the pre-pit synchronization signal 1 and the pre-pit synchronization signal 2 as described above. Thus, by combining the synchronization signal pattern information of the two types of pre-pit synchronization signals 1 and 2 using 1 bit and the 4-bit relative address information in the pre-pit data, combined address information of a total of 5 bits is obtained. Thus, address information for 32 sectors constituting one ECC block can be obtained from the combination address information. In other words, 1
By using part of the relative address information in the pre-pit data with the synchronizing signal pattern information based on the two types of pre-pit synchronizing signals 1 and 2 using bits, the amount of address information in the ECC block can be increased.

Further, the two pre-pit synchronization signals 1 and 2 are used as the most significant bit of the relative sector address, and the pre-pit synchronization signal 1 is synchronized with the first half of 16 sectors in one ECC block. The pre-pit synchronization signal 2 is a synchronization code of the latter 16 sectors. However, the present invention is not limited to this. For example, the pre-pit synchronization signal 1
It is also possible to assign the pre-pit synchronization signal 2 to even-numbered sectors.

According to the present invention, not limited to the example as shown in FIG. 8B, the pre-pit synchronization signal in the land pre-pits 5 also serves as address information, so that it has n pieces of synchronization signal pattern information. The combined address information obtained by combining the pre-pit synchronization signal and the m-bit address bits in the pre-pit data can represent the relative address of n × 2 ^m sectors, which can be represented by only 2 ^m sectors conventionally. Even when the number of sectors in one ECC block is large, the optical disk device 20 of the first and second embodiments
A and 20B (FIGS. 9 and 15) enable appropriate recording and increase the number of sectors per ECC block to improve the error correction capability, resulting in a high-density and higher-precision optical disc 1. Can be

<Optical Disk Apparatus According to First Embodiment> FIG. 9 is a block diagram showing an optical disk apparatus according to a first embodiment of the present invention, and FIG. FIG. 11 is a diagram for explaining a case of detecting a land prepit on a mountain side (outer circumference side) formed on a land of an optical disc. FIG. 11 shows a case where a land prepit signal based on a land prepit on a mountain side (outer circumference side) is binarized. FIG. 12 shows a case where a land pre-pit on the valley side (inner circumference side) formed on a land of an optical disk is detected using the optical disk apparatus of the first embodiment according to the present invention. FIG. 13 is a diagram showing each signal when binarizing the land prepit signal by the land prepit on the valley side (inner circumference side), and FIG. 14 is a land prepit on the peak side (outer circumference side). Land prep Signal, a land pre-pit signals by the land prepit valley (inner circumferential side), respectively 2
It is a figure for explaining the state at the time of value conversion.

As shown in FIG. 9, in the optical disk recording / reproducing apparatus 20A of the first embodiment according to the present invention, the above-mentioned optical disk 1 is rotatably mounted on a turntable 22 fixed to a shaft of a spindle motor 21. I have. Further, an optical pickup 23 is provided movably in the radial direction of the optical disk 1 so as to face the optical disk 1. The optical pickup 23 irradiates a laser beam from a semiconductor laser (not shown) installed therein to a beam spot B on the optical disk 1 by an objective lens (not shown),
The return light reflected by the metal reflective layer 7 (FIG. 1) of the optical disk 1 from the beam spot B irradiated on the optical disk 1 is detected by a four-divided photodetector PD.

In the optical pickup 23, when recording an information signal on the phase change recording layer 6 (FIG. 1) of the optical disk 1, a recording beam spot B having a strong laser power is applied to the phase change recording layer 6 of the optical disk 1. When reproducing the information signal recorded on the phase change recording layer 6 of the optical disc 1, the reproduction beam spot B having a weak laser power is irradiated on the phase change recording layer 6 of the optical disc 1. Now, only the reproduction time will be described.

The reflected light returned from the optical disk 1 is photoelectrically converted by a four-divided photodetector PD in the optical pickup 23, and is input to the preamplifier 24.

Here, as shown in FIG. 10A and FIG. 12A, the quadrant photodetector PD is formed in a substantially rectangular shape, and is formed in the radial direction of the optical disk 1. Along the line and groove direction (track direction)
Although the entire light receiving area is divided into four equal parts by the straight line along the line, the return beam spot B formed on the photodetector PD is divided into two light receiving areas A and B on the outer peripheral side of the optical disc 1. And the two light receiving areas C on the inner circumference side
The light receiving area D is divided into two sets and a straight line along the track direction of the optical disc 1 is divided into two.

In the first embodiment, a four-division photodetector PD is used. However, a two-division photodetector (not shown) is obtained by dividing the straight line along the track direction of the optical disc 1 into two parts. ) May be used. In this case, the first light receiving area is (A) in the four-division photo detector PD.
+ B), and the second light receiving region may be handled as a region corresponding to (C + D) in the four-division photodetector PD.

Returning to FIG. 9, the preamplifier 24 amplifies each output of the light receiving areas A to D of the photodetector PD. Thereafter, the outputs of the light receiving areas A and B amplified by the preamplifier 24 are input to an (A + B) circuit 25, where they are added to obtain an (A + B) signal.
+ B) signal is input to the {(A + B) -k (C + D)} circuit 26.

The outputs of the light receiving areas C and D amplified by the preamplifier 24 are input to a (C + D) circuit 27, where they are added, and then input to a -k coefficient circuit 28. , The (C + D) signal is multiplied by a coefficient of -k to obtain a {-k (C + D)} signal, and the {-k (C + D)} signal is converted to {(A + B) -k (C +
D) Input to the circuit 26. At this time, the coefficient of -k is
According to the pit shape in the phase change recording layer 6 (FIG. 1) of the optical disc 1, the value is set to about -0.7 to -0.9.

Thereafter, the {(A + B) -k (C + D)} circuit 26 uses the (A + B) signal from the (A + B) circuit 25 and the {-k (C + D)} signal from the -k coefficient circuit 28. Radial push-pull signal ｛(A + B) -k (C
+ D)} is obtained. The radial push-pull signal {(A + B) -k (C + D)} includes a wobble signal WBL by the groove 3 and a land pre-pit signal LPP by the land pre-pit 5.

Note that, unlike the above, the (A + B) signal may be multiplied by a coefficient of −1 / k to obtain a radial push-pull signal {(C + D) −1 / k (A + B)}.

Thereafter, the radial push-pull signal from the {(A + B) -k (C + D)} circuit 26 {(A + B)-
k (C + D)} is a sample / hold circuit (hereinafter, S
/ H circuit) 29 and first and second LPPs 2 to be described later.
These are input to the value conversion circuits 37 and 40, respectively.

The S / H circuit 29 is a wobble signal extracting means for extracting the wobble signal WBL of one groove 3 when scanning while tracking one groove 3 with the beam spot B. This S / H
In the circuit 29, when the land pre-pit signal LPP does not exist, the radial push-pull signal {(A + B) -k
(C + D)}, and mask (hold) the land pre-pit signal LPP during the period in which the land pre-pit signal LPP is present by the LPP window opening signal from the LPP window opening circuit 32 described later. As a result, only the wobble signal WBL is extracted, and only the wobble signal WBL is input to a band-pass filter circuit (hereinafter, referred to as a BPF circuit) 30 where noise components are removed. The WBL is input to the WBL binarization circuit 31, the addition circuit 36, and the subtraction circuit 39, respectively.

In the above-described WBL binarization circuit 31, BP
The wobble signal WBL from the F circuit 30 is binarized, and the binarized wobble signal WBL is input to the LPP window opening circuit 32 and the WBL / PLL circuit 33, respectively.

In the LPP window opening circuit 32, 2
Based on the rising edge of the digitized wobble signal WBL, an LPP window opening signal is generated only during a period in which the land pre-pit signal LPP exists, and this LPP window opening signal is sent to the S / H circuit 29. Supplying.

In the WBL / PLL circuit 33, the internal PLL is controlled based on the binarized wobble signal WBL.
To generate a clock.
It is supplied to the second address decode circuits 38 and 41, respectively.

The CPU 34 for controlling the entire optical disc apparatus 20 A operates the bias setting circuit 35, and supplies the first DC bias voltage to be supplied to the adding circuit 36 by the bias circuit 35 and the subtraction circuit 39. And a second DC bias voltage to be supplied.

Next, the adder circuit 36, the first LPP binarization circuit 37, and the first address decode circuit 38 perform scanning while tracking one groove 3 with the beam spot B, and Land pre-pits 5 on the mountain side (outer circumference side) formed on the land 4 on the side
This is a circuit for detecting a. Here, the addition circuit 36
, A wobble signal WBL output from the BPF 30 is input, a first DC bias voltage from the bias setting circuit 35 is added to the wobble signal WBL, and the added value is the land prepit on the mountain side (outer circumference side). This is set as the first slice level (threshold) when binarizing the land pre-pit signal LPP by 5a.

Thereafter, in the first LPP binarization circuit 37,
{(A + B) -k (C + D)} radial push-pull signal input from circuit 26 {(A + B) -k (C +
D) Only the land pre-pit signal LPP by the land pre-pit 5a on the mountain side (outer circumference side) is binarized and binarized based on the first slice level (threshold) set by the addition circuit 36 for｝. The land pre-pit signal LPP by the land pre-pit 5a on the mountain side (outer circumference side) is the first signal.
It is input to the address decode circuit 38.

In the above-mentioned first address decode circuit 38, the lands formed by the binarized mountain-side (outer-peripheral-side) land prepits 5a from the first LPP binarization circuit 37 are referenced to the clock from the WBL / PLL circuit 33. By decoding the pre-pit signal LPP, the mountain side (outer circumference side)
Can be reliably detected.

On the other hand, the subtraction circuit 39, the second LPP binarization circuit 40, and the second address decode circuit 41 scan the one groove 3 while tracking the one groove 3 with the beam spot B. Land pre-pit 5 on the valley side (inner circumference side) formed on the land 4 on the side
This is a circuit for detecting b. Here, the subtraction circuit 39
, The wobble signal WBL output from the BPF 30 is input, the second DC bias voltage from the bias setting circuit 35 is subtracted from the wobble signal WBL, and the subtracted value is the valley (inner circumference) land. This is set as the second slice level (threshold) when binarizing the land pre-pit signal LPP by the pre-pit 5b.

Thereafter, in the second LPP binarization circuit 40,
{(A + B) -k (C + D)} radial push-pull signal input from circuit 26 {(A + B) -k (C +
D) Only the land pre-pit signal LPP by the land pre-pit 5b on the valley side (inner circumference side) is binarized based on the second slice level (threshold value) set by the subtraction circuit 39 with respect to さ れ. The land pre-pit signal LPP by the land pre-pit 5b on the valley side (inner circumference side) is
It is input to the address decode circuit 41.

In the second address decode circuit 41 described above, the binarized valley side (inner circumference side) land pre-pit 5b from the second LPP binarization circuit 40 is referenced with respect to the clock from the WBL / PLL circuit 33. By decoding the land pre-pit signal LPP by the valley side (inner circumference side)
Can be reliably detected.

The output signal of the land pre-pit 5a on the mountain side (outer side) decoded by the first address decode circuit 38 and the land pre-pit 5b on the valley side (inner side) decoded by the second address decode circuit 41 Is supplied to the access control circuit 42 via the CPU 34, so that the address information based on the land prepits 5a on the mountain side (outer side) and the address information based on the land prepits 5b on the valley side (inner side) are obtained. , The optical pickup 23 can be reliably moved to the target address position.

The (A + B) circuit 25 outputs (A +
The (B) signal and the (C + D) signal from the (C + D) circuit 27 are input to an (A + B + C + D) circuit 43, where they are added to obtain a (A + B + C + D) signal, and this (A +
The information signal from the optical disk 1 is reproduced by decoding the (B + C + D) signal by the information signal decoding circuit 44.

Here, the optical disk device 20 of the first embodiment
FIG. 9 and FIGS. 10 to 14 show a case where the land prepits 5a and 5b on the peak side (outer peripheral side) and the valley side (inner peripheral side), which are the main parts of the present invention, are reliably detected. This will be described in detail.

First, when detecting the land prepit 5a on the mountain side (outer side), as shown in FIG. 10A, when one groove 3 is scanned by the beam spot B, the photo detector PD In this state, the land pre-pits 5a on the mountain side (outer peripheral side) exist on the light receiving areas A and B sides of the photo detector PD, and the light receiving areas C and D of the photodetector PD.
There is no land pre-pit 5 on the side. In this state, as shown in FIG. 10B, (A + B) is applied to the land prepit 5a on the mountain side (outer circumference side).
The (A + B) signal obtained by the circuit 25 is higher than the 0 level and higher than the wobble signal WBL.
There is P.

On the other hand, the signal detected by the photodetector PD is affected by the diffraction phenomenon caused by the beam spot B, so that the light receiving area C of the photodetector PD with respect to the land prepit 5a on the mountain side (outer peripheral side). , And D, the (C + D) circuit 27 obtains a (C + D) signal obtained by inverting the (A + B) signal upside down, and this (C + D) signal is above the 0 level and the wobble signal Land prepit 5 on the mountain side (outer circumference side) below WBL
a there is a land pre-pit signal LPP.

Thereafter, when the (C + D) signal is multiplied by the -k coefficient in the -k coefficient circuit 28, the (A + B) signal becomes higher than the 0 level as shown in FIG.
The -k (C + D) signal is obtained below the level, and the (A + B) signal and the -k (C + D) signal are both land prepit signals LPP by the land prepits 5a on the mountain side (outer circumference side) above the wobble signal WBL. And the direction is expressed as {(A + B) -k (C + D)}.
When calculated by the circuit 26, as shown in FIG.
A radial push-pull signal ｛(A + B) -k such that there is a land pre-pit signal LPP by the land pre-pit 5a on the mountain side (outer circumference side) above the wobble signal WBL.
(C + D)} is obtained.

The groove 3 is a sine curve or c.
Because it is wobbled in the shape of an Osine curve, the BPF
30 based on the wobble signal WBL obtained through
The wobble signal WBL is binarized by the WBL binarization circuit 31 to obtain a binarized wobble signal WBL as shown in FIG.

In the LPP window opening circuit 32, the lands formed by the land prepits 5a and 5b on the mountain side (outer side) and the valley side (inner side) with reference to the rising edge of the binarized wobble signal WBL. Only during the period in which the pre-pit signal LPP exists, L as shown in FIG.
A PP window opening signal is generated. At this time, the land prepits 5a and 5b on the mountain side (outer side) and the valley side (inner side)
The land pre-pit signal LPP is the wobble signal W
Since it is known in advance that the BL exists at a position spaced by a predetermined period from the rising edge of BL, it is possible to generate an LPP window opening signal.

In the S / H circuit 29, the land prepits 5a and 5b on the mountain side (outer side) and the valley side (inner side) only during the period when the LPP window is opened by the LPP window opening signal. The masking (holding) of the land pre-pit signal LPP is performed, so that a wobble signal WBL having no noise is obtained during the LPP window opening signal period as shown in FIG.

Further, a wobble signal WBL from the BPF 30 as shown in FIG.
The first DC bias voltage of + D1V from the bias setting circuit 35 as shown in FIG. 11F is input, and the two are added to form the land pre-pit signal LPP by the land pre-pit 5a on the mountain side (outer side). The first slice level (threshold) is set as a value which is higher than the wobbling signal WBL by + D1V as shown in FIG. 11 (g).

Then, in the first LPP binarization circuit 37,
Based on the first slice level (threshold) shown in FIG. 11G, the radial push-pull signal input from the {(A + B) -k (C + D)} circuit 26 {(A + B) -k
(C + D)}, only the land pre-pit signal LPP by the land pre-pit 5a on the mountain side (outer side) is binarized, and the land pre-pit 5a on the mountain side (outer side) as shown in FIG. Land pre-pit signal LPP
Is obtained.

Next, when detecting the land pre-pits 5b on the valley side (inner circumference side), when scanning one groove 3 with the beam spot B as shown in FIG. The land pre-pits 5 are not present on the light receiving areas A and B of the detector PD, and the land pre-pits on the valley side (inner circumference) are located on the light receiving areas C and D of the photo detector PD. 5b is present. In this state, as shown in FIG. 12B, (C + D) is applied to the land prepit 5b on the valley side (inner circumference side).
The (C + D) signal obtained by the circuit 27 is a land pre-pit signal LP by a land pre-pit 5b on the valley side (inner circumference side) above the 0 level and above the wobble signal WBL.
There is P.

On the other hand, the signal detected by the photodetector PD is affected by the diffraction phenomenon caused by the beam spot B, so that the light received by the photodetector PD with respect to the land prepit 5b on the valley side (inner circumference side). The areas A and B are also affected. In the (A + B) circuit 25, an (A + B) signal obtained by inverting the (C + D) signal upside down is obtained, and the (A + B) signal is higher than the 0 level and Land pre-pit 5 on the valley side (inner side) below wobble signal WBL
b, there is a land pre-pit signal LPP.

Thereafter, when the (C + D) signal is multiplied by the coefficient of -k in the -k coefficient circuit 28, as shown in FIG.
The -k (C + D) signal is obtained below the level, and the (A + B) signal and the -k (C + D) signal are both land prepits 5b on the valley side (inner circumference side) below the wobble signal WBL. The signal LPP has a direction as if it exists, which is represented by {(A + B) -k (C + D)}.
When operated by the circuit 26, as shown in FIG.
A radial push-pull signal ｛(A + B) -k in which a land pre-pit signal LPP by a land pre-pit 5b on the valley side (inner circumference side) is below the wobble signal WBL.
(C + D)} is obtained.

The groove 3 has a sine curve or c.
Because it is wobbled in the shape of an Osine curve, the BPF
30 based on the wobble signal WBL obtained through
The wobble signal WBL is binarized by the WBL binarization circuit 31 to obtain a binarized wobble signal WBL as shown in FIG.

In the LPP window opening circuit 32, as described above, the peak side (outer side) and the valley side (inner side) are based on the rising edge of the binarized wobble signal WBL.
The window opening signal for LPP as shown in FIG. 13C is generated only during the period in which the land pre-pit signal LPP by the land pre-pits 5a and 5b exists.

Further, the S / H circuit 29 masks (holds) the land pre-pit signal LPP by the land pre-pits 5a and 5b on the crest side (outer side) and the valley side (inner side) as described above. Therefore, as shown in FIG. 13D, a wobble signal WBL having no noise is obtained during the LPP window opening signal period.

Further, the wobble signal WBL from the BPF 30 as shown in FIG.
The second DC bias voltage of + D2V from the bias setting circuit 35 as shown in FIG.
By subtracting the second DC bias voltage from the wobble signal WBL from F30, the second slice level (threshold value) of the land prepit signal LPP paired with the land prepit 5b on the valley side (inner circumference side) is set as shown in FIG. As shown in (g), the value is set as a value lower than the wobbling signal WBL by -D2V.

Then, in the second LPP binarization circuit 40,
Based on the second slice level (threshold) shown in FIG. 13G, the radial push-pull signal input from the {(A + B) -k (C + D)} circuit 26 {(A + B) -k
With respect to (C + D) ラ ン ド, only the land pre-pit signal LPP by the land pre-pit 5b on the valley side (inner side) is binarized, and as shown in FIG. Land pre-pit signal LPP by land pre-pit 5b
Is obtained.

As described above, along the groove 3, the land pre-pit 5a on the mountain side (outer circumference side) and the land pre-pit 5a on the valley side (inner circumference side)
14A together with the land pre-pits 5b of FIG.
14B is higher than the wobble signal WBL, and the land prepit signal LPP by the land prepit 5a is binarized at this first slice level, as shown in FIG. 14B. On the other hand, the second slice level to the land prepit signal LPP by the land prepit 5b on the valley side (inner side) is below the wobble signal WBL, and the land by the land prepit 5b at this second slice level. When the pre-pit signal LPP is binarized, the result is as shown in FIG.

Therefore, the optical disk device 20 of the first embodiment
In A, the peak side of the waveform of the groove 3 (the outer peripheral side or the inner peripheral side)
By detecting the land pre-pits 5a connected to the valleys and the land pre-pits 5b connected to the valley side (inner side or outer side) of the waveform of the groove 3, the land pre-pits 5a on the mountain side cannot be detected. Even if the address information of the groove 3 being scanned by the beam spot B cannot be read, the address information of the groove 3 being scanned by the beam spot B can be obtained by detecting the land prepit 5b on the valley side. Even if the track is narrowed as the density is increased to 1, the detection accuracy of the land pre-pits 5 can be improved.

<Optical Disk Apparatus of Second Embodiment> FIG. 15 is a block diagram showing an optical disk apparatus of a second embodiment according to the present invention.

The optical disk device 20B of the second embodiment according to the present invention shown in FIG. 15 is different from the optical disk device 20A of the first embodiment described above with reference to FIG. Here, for convenience of explanation, the same reference numerals are given to the components described above,
In addition, different constituent members are given new reference numerals, and only different points from the optical disk device 20A of the first embodiment will be described.

The optical disk device 20 of the second embodiment described above
In B, a radial push-pull signal is generated from each output from the light receiving areas A to D of the photodetector PD, and the land pre-pit 5 is detected from the radial push-pull signal. When detecting the pit 5a, the (k) coefficient circuit 28A applies -k1 to the (C + D) signal from the (C + D) circuit 27.
, And then multiply by {(A + B) -k1 (C + D)}
The first radial push-pull signal ｛(A +
B) -k1 (C + D)}, while detecting the land prepit 5b on the valley side (inner side), the -k2 coefficient circuit 2 for the (C + D) signal from the (C + D) circuit 27
After multiplying the coefficient of −k2 by 8B, ｛(A + B) −k2
(C + D) {The second radial push-pull signal {(A + B) -k2 (C + D)} is obtained by the circuit 26B.
This is different from the embodiment. At this time, when the coefficient value of -k1 and the coefficient value of -k2 are the same, the first embodiment may be applied, and when the coefficient values of the two are different, the second embodiment may be applied. .

By configuring the optical disk device 20B of the second embodiment as described above, when the land prepits 5a and 5b on the hill side (outer side) and the valley side (inner side) are detected, the hill side (outer side) is detected. And the input balances of the first and second radial push-pull signals for the valley side (inner circumference side) are calculated by respective coefficients -k1, -k.
2 can be set independently, so that optimum first and second radial push-pull signals with little detection error can be obtained, respectively, and the peak side (outer side) and the valley side (inner side)
Of the land pre-pits 5a and 5b can be improved.

At this time, when applied to the optical disc 1 under development, in the second embodiment, for example, the coefficient value of -k1 is set to-
It is set to about 0.7 to -0.9, and the coefficient value of -k2 is-
When it is set to about 0.9 to -1.1, the detection reliability of the land prepits 5a and 5b on the peak side (outer peripheral side) and the valley side (inner peripheral side) can be ensured.

Then, {(A + B) -k1 (C + D)}
The first radial push-pull signal ｛(A
+ B) -k1 (C + D)} is connected to the S / H circuit 29A and the BPF
30A and the bias setting circuit 35
A first slice level (threshold) for the land pre-pit signal LPP by the land pre-pit 5a on the mountain side (outer side) is set by adding the first DC voltage of + D1V from A to the addition circuit 36.

On the other hand, {(A + B) -k2 (C + D)} the second radial push-pull signal from the circuit 26B {(A +
B) -k2 (C + D)} is converted to the S / H circuit 29B and the BPF3.
By subtracting the + D2V second DC voltage from the bias setting circuit 35B from the output obtained through the 0B in order by the subtraction circuit 39, the land prepit signal by the land prepit 5b on the valley side (inner circumference side) is obtained. Second for LPP
The slice level (threshold) is set.

The S / H circuit 29A, shown in FIG.
29B, BPF circuits 30A and 30B, WBL binarization circuits 31A and 31B, and LPP window opening circuits 32A and 3B.
2B, the WBL / PLL circuits 33A and 33B, and the bias setting circuits 35A and 35B are the same as those described in the first embodiment.
/ H circuit 29, BPF circuit 30, WBL binarization circuit 31, LPP window opening circuit 32, WBL / PLL circuit 33, and bias setting circuit 35. It is not necessary to divide the components, and the components are shown separately in order to avoid complication of the lead lines. Further, since these components are described in the first embodiment, the description will be omitted.

It is to be noted that, unlike the above, the (A + B) signal is multiplied by a coefficient of −1 / k1 and a coefficient of −1 / k2, respectively, and the first radial push-pull signal ｛(C + D) −1 /
k1 (A + B)} and the second radial push-pull signal {(C + D) -1 / k2 (A + B)}.

In the second embodiment described above, when the radial push-pull signal is generated to detect the land prepits 5a and 5b on the peak side (outer side) and the valley side (inner side),
Coefficients for the first and second radial push-pull signals are expressed as a land pre-pit 5a on the mountain side (outer side) and a valley side (inner side).
And the land pre-pits 5b are set to different values, so that the present invention can be applied to any type of optical disc 1 having the land pre-pits 5.

Next, a modified example of the optical disk devices 20A and 20B of the first and second embodiments will be briefly described.

In this modified example, when detecting the land prepit 5b connected to the valley side of the waveform of the groove 3, the wobble signal extracting means 29 is used as in the first and second embodiments.
The DC bias voltage from the bias setting circuit 35 (or 35B) is subtracted from the wobble signal of the groove 3 extracted by (or 29B) or 30 (or 30B), and the land prepit 5b by the land prepit 5b on the valley side is subtracted. Set the slice level when binarizing the signal,
(C + D)｝ circuit 26 or ｛(A + B) −k2 (C +
D) With respect to the radial push-pull signal from the circuit 26B, the land prepit signal on the valley side is binarized based on the slice level described above. On the other hand, when detecting the land prepit 5a connected to the peak of the waveform of the groove 3, the {(A + B) -k (C + D)} circuit 26
Alternatively, the wobble signal extracted by the conventional method is subjected to peak detection with respect to the radial push-pull signal from the {(A + B) -k1 (C + D)} circuit 26A by a known method, and a DC bias voltage is added to the peak detection waveform. Then, the slice level at the time of binarization of the land prepit signal by the land prepit 5a on the mountain side is set, and the land prepit signal on the mountain side is binarized.

Therefore, in the above-described modification, the groove 3
By applying the technical idea of the present invention to the land prepit 5b which is difficult to detect by being connected to the valley side of the waveform, the land prepit signal on the valley side can be reliably read,
On the other hand, a well-known peak detection method may be applied to the land prepit 5a which is easily detected by being connected to the peak side of the waveform of the groove 3.

[0120]

According to the optical disk apparatus of the present invention described in detail above, according to the first aspect, the track formed by pairing a groove wobbled on both sides and a land located between adjacent grooves is formed on the disk. It is formed spirally or concentrically on the substrate, and address information to the information signal to be recorded in the groove is preliminarily formed as land prepits on the land, and the land prepits are formed on both sides of the groove. Is connected to the peak of the waveform of the groove, and the other is connected to the valley of the waveform of the groove. While scanning the groove on the optical disk with, the reflected light from the optical disk is divided into at least two along the track direction. When detecting the land pre-pits connected to the groove from the radial push-pull signal based on the difference signal between the outputs of the first and second light-receiving areas, the light is received by the photodetector having the two light-receiving areas. Since land pre-pits connected to the ridge side of the groove waveform and land pre-pits connected to the valley side of the groove waveform are respectively detected, each land pre-pit signal by each land pre-pit is binarized. While scanning the groove with the beam spot, the land pre-pits connected to the ridge side (outer or inner circumference side) of the groove waveform and the land pre-pits connected to the valley side (inner or outer circumference side) of the groove waveform. By detecting land pre-pits, if the land pre-pits on the mountain side cannot be detected, the Even if the dress information cannot be read, the address information of the groove being scanned by the beam spot can be obtained by detecting the land pre-pits on the valley side. However, the accuracy of land pre-pit detection can be improved.

According to the second aspect of the present invention, in particular, when detecting a wobble signal extracting means for extracting a wobble signal of a groove from a radial push-pull signal, and detecting a land prepit connected to the crest of the waveform of the groove, Adding means for adding a first DC bias voltage to the groove wobble signal extracted by the wobble signal extracting means to set a first slice level when binarizing the land prepit signal by the land prepit on the mountain side; When detecting the land pre-pits connected to the valley side of the groove waveform, the second DC bias voltage is subtracted from the groove wobble signal extracted by the wobble signal extraction means, and the land pre-pits on the valley side are detected. 2 to land pre-pit signal
Subtraction means for setting a second slice level at the time of binarization, and first LPP binarization means for binarizing a mountain side land pre-pit signal based on the first slice level set by the addition means for the radial push-pull signal And a second LPP binarizing means for binarizing the land pre-pit signal on the valley side based on the second slice level set by the subtracting means with respect to the radial push-pull signal. A land pre-pit signal connected to a land pre-pit connected to the outer circumference or inner circumference and a land pre-pit signal connected to a valley side (inner or outer circumference) of the groove waveform are reliably detected. The address for the optical pickup is determined by the respective address information based on the land pre-pit signals on the mountain side and the valley side. It can be reliably moved to the location.

According to the third aspect of the present invention, a land pre-pit signal formed by a land pre-pit connected to the peak (outer or inner circumference) of the groove waveform and a valley (inner or outer circumference) of the groove waveform. When binarizing the land pre-pit signals by the land pre-pits connected to the land pre-pit signal, masking (holding) of both land pre-pit signals is performed especially during the period in which the land pre-pit signals on the mountain side and the valley side exist. ), The wobble signal can be extracted without being affected by the land pre-pit signal, and the first and second slice levels can be set by the wobble signal.

According to the present invention, when generating a radial push-pull signal, different coefficients are used for one of the outputs of the first and second light receiving areas of the photodetector. And a first radial push-pull signal for detecting a land pre-pit signal on the mountain side based on a difference signal between one output multiplied by each coefficient and the other output not multiplied by the coefficient, and a land pre-pit signal on the valley side. Since the second radial push-pull signal for detecting the pit signal is respectively generated, the mountain side (outer circumference side)
When detecting each land prepit on the valley side (inner circumference side),
The input balance of the first and second radial push-pull signals for the mountain side (outer circumference side) and the valley side (inner circumference side) is calculated by each coefficient -k1,
-K2 can be set independently of each other, so that an optimal radial push-pull signal with few detection errors can be obtained, and the reliability of the detection of the land prepits on the peak side (outer side) and the valley side (inner side) can be improved. Can be improved.

Further, according to the fifth aspect, in particular, the wobble signal extracting means for extracting the wobble signal of the groove from the radial push-pull signal and the detection of the land pre-pits connected to the valley side of the waveform of the groove. Subtracting means for subtracting a DC bias voltage from the wobble signal of the groove extracted by the wobble signal extracting means to set a slice level when binarizing the land prepit signal by the land prepit on the valley side; LPP for binarizing a valley-side land pre-pit signal based on a slice level set by a subtraction means for a radial push-pull signal
Since the present invention is provided with the binarizing means, the technical idea of the present invention is applied to land prepits which are difficult to detect by being connected to the valley side of the groove waveform, so that the land prepit signal on the valley side can be reliably obtained. On the other hand, a well-known peak detection method may be applied to land prepits that can be easily detected by being connected to the crest side of the groove waveform.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining an optical disk applied to an optical disk device according to the present invention.

FIG. 2 is a plan view showing a configuration of a zone in the optical disc shown in FIG.

FIG. 3 is a diagram schematically showing a wobble cycle of a wobbled groove divided into an inner peripheral side and an outer peripheral side in the optical disc shown in FIGS. 1 and 2;

FIG. 4 is a diagram for explaining land pre-pits formed on lands in an optical disc applied to the optical disc apparatus according to the present invention, and FIG. 4 (a) schematically shows the shape of land pre-pits; (B) is a diagram showing a waveform of a land pre-pit signal when a land pre-pit is detected.

FIG. 5 is a diagram showing a signal form in a groove synchronization frame.

FIG. 6 is a diagram for explaining types of land prepits formed on lands.

FIG. 7 is a diagram showing a plurality of land prepits provided corresponding to one sector.

FIG. 8A is a diagram showing land pre-pit blocks of one sector in one ECC block, and FIG. 8B is a diagram showing land pre-pit blocks corresponding to one ECC block.

FIG. 9 is a configuration diagram illustrating an optical disc device according to a first embodiment of the present invention.

FIG. 10 is a diagram for explaining a case where a land prepit on a mountain side (outer peripheral side) formed on a land of an optical disk is detected by using the optical disk device of the first embodiment according to the present invention.

FIG. 11 is a diagram showing each signal when binarizing a land prepit signal by a land prepit on the mountain side (outer circumference side).

FIG. 12 is a diagram for explaining a case where a land prepit on a valley side (inner circumference side) formed on a land of an optical disk is detected by using the optical disk device of the first embodiment according to the present invention.

FIG. 13 is a diagram showing each signal when binarizing a land prepit signal by a land prepit on the valley side (inner circumference side).

FIG. 14 is a diagram for explaining a state in which a land prepit signal by a land prepit on a mountain side (outer circumference side) and a land prepit signal by a land prepit on a valley side (inner circumference side) are binarized. FIG.

FIG. 15 is a configuration diagram illustrating an optical disc device according to a second embodiment of the present invention.

16A and 16B are diagrams for explaining an example of a conventional optical disk, in which FIG. 16A shows a track in which a wobbled groove and a land located between adjacent grooves are paired,
FIG. 4B is a diagram showing pulses generated by address pits on the inner and outer peripheral sides.

FIG. 17 is a diagram for explaining another example of a conventional optical disk.

18 (a) schematically shows a conventional optical disc where a wobble groove has an opposite wobble phase, and FIG. 18 (b) shows a land formed on a land adjacent to both sides of one groove. It is the figure which showed typically the place where prepits overlap.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Disk board, 3 ... Groove, 4
... land, 5 ... land prepit, 5a ... land prepit on the mountain side (outer circumference side), 5b ... land prepit on the valley side (inner circumference side), 6 ... phase change recording layer, 7 ... metal reflection layer, 2
0A: optical disk device of the first embodiment, 20B: optical disk device of the second embodiment, 21: spindle motor, 22 ...
Turntable, 23: Optical pickup, 24: Preamplifier, 25: (A + B) circuit, 26: ｛(A + B) -k
(C + D)｝ circuit, 26A... {(A + B) -k1 (C +
D) {Circuit, 26B ... {(A + B) -k2 (C + D)}}
Circuit, 27 ... (C + D) circuit, 28 ...- k coefficient circuit, 2
8A ...- k1 coefficient circuit, 28B ...- k2 coefficient circuit, 2
9, 29A, 29B ... sample / hold circuit (S / H
Circuits), 30, 30A, 30B ... band-pass filter circuits (BPF circuits), 31, 31A, 31B ... WBL binarization circuits, 32, 32A, 32B ... LPP window opening circuits,
33, 33A, 33B ... WBL / PLL circuit, 34 ... C
PU, 35, 35A, 35B ... bias setting circuit, 36
... addition circuit, 37 ... first LPP binarization circuit, 38 ... first
Address decode circuit, 39: subtraction circuit, 40: 2nd L
PP binarization circuit, 41... Second address decode circuit, 4
2. Access control circuit, 43 (A + B + C + D) circuit, 44 ... Information signal decoding circuit, B ... Beam spot, PD ... Photo detector.

Claims (5)

[Claims] 1. A track comprising a pair of grooves wobbled (meandering) on both sides and a land located between adjacent grooves is formed in a spiral or concentric shape on a disk substrate, and is formed on the land. The land pre-pits are formed in advance with address information to information signals to be recorded in the groove as land pre-pits. Using an optical disc formed by connecting the grooves to the troughs of the groove and displacing the positions so that they do not coincide with each other while maintaining a predetermined interval,
While scanning the groove on the optical disk with the beam spot, the reflected light from the optical disk is received by a photodetector having first and second light receiving regions obtained by dividing the reflected light from the optical disk at least into two along the track direction. An optical disc device configured to detect the land pre-pits connected to the groove from a radial push-pull signal based on a difference signal between outputs of the two light receiving areas, wherein the radial push-pull signal is applied to a peak side of a waveform of the groove from the radial push-pull signal. An optical disc characterized by detecting the connected land pre-pits and the land pre-pits connected to the valley side of the groove waveform and binarizing each land pre-pit signal by each land pre-pit. apparatus. 2. A track comprising a pair of grooves wobbled on both sides and a land located between adjacent grooves is formed in a spiral or concentric shape on a disk substrate, and is formed on the land. The land pre-pits are formed in advance with address information to information signals to be recorded in the groove as land pre-pits, and one of the land pre-pits is connected to both sides of the groove at the peak of the waveform of the groove, and the other is connected to the other side. Using an optical disc formed by connecting the grooves to the troughs of the groove and displacing the positions so that they do not coincide with each other while maintaining a predetermined interval,
While scanning the groove on the optical disk with the beam spot, the reflected light from the optical disk is received by a photodetector having first and second light receiving regions obtained by dividing the reflected light from the optical disk at least into two along the track direction. (2) An optical disc device configured to detect the land pre-pits connected to the groove from a radial push-pull signal based on a difference signal between outputs of the respective light receiving areas, and extract a wobble signal of the groove from the radial push-pull signal. A wobble signal extracting means for detecting the land prepit connected to the crest side of the groove waveform by adding a first DC bias voltage to the wobble signal of the groove extracted by the wobble signal extracting means. The binary value to the land pre-pit signal by the land pre-pit on the mountain side Adding means for setting the first slice level at the time; and detecting the land pre-pits connected to the valley side of the groove waveform with respect to the wobble signal of the groove extracted by the wobble signal extracting means. Subtraction means for subtracting a second DC bias voltage to set a second slice level when binarizing the land prepit signal by the land prepit on the valley side; and adding means for the radial push-pull signal First LPP binarization means for binarizing the land pre-pit signal on the mountain side based on the first slice level set in the step (a), and the second slice level set in the subtraction means for the radial push-pull signal. And a second LPP binarizing means for binarizing the land pre-pit signal on the valley side based on the signal. Device. 3. The optical disk device according to claim 2, wherein the wobble signal extracting means performs sampling on the radial push-pull signal when the land pre-pit signal on the hill side and the valley side does not exist, and outputs the wobble signal on the hill side and the valley. An optical disc device for extracting the wobble signal by masking (holding) both land pre-pit signals during a period in which the land pre-pit signal exists. 4. The optical disk device according to claim 1, wherein when the radial push-pull signal is generated, each output of the first and second light receiving areas of the photo detector is generated. Multiplying any one of the outputs by a different coefficient, and detecting the land prepit signal on the mountain side by a difference signal between one output multiplied by each coefficient and the other output not multiplied by the coefficient. An optical disc apparatus for generating a first radial push-pull signal and a second radial push-pull signal for detecting the land pre-pit signal on the valley side. 5. A track comprising a pair of wobbled grooves on both sides and lands located between adjacent grooves is formed in a spiral or concentric shape on a disk substrate, and is formed on the lands. The land pre-pits are formed in advance with address information to information signals to be recorded in the groove as land pre-pits. Using an optical disc formed by connecting the grooves to the troughs of the groove and displacing the positions so that they do not coincide with each other while maintaining a predetermined interval,
While scanning the groove on the optical disk with the beam spot, the reflected light from the optical disk is received by a photodetector having first and second light receiving regions obtained by dividing the reflected light from the optical disk at least into two along the track direction. (2) An optical disc device configured to detect the land pre-pits connected to the groove from a radial push-pull signal based on a difference signal between outputs of the respective light receiving areas, and extract a wobble signal of the groove from the radial push-pull signal. A wobble signal extracting means for detecting the land prepits connected to the valley side of the groove waveform by subtracting a DC bias voltage from the wobble signal of the groove extracted by the wobble signal extracting means. At the time of binarization to the land pre-pit signal by the land pre-pit on the valley side Subtraction means for setting a slice level; and LPP binarization means for binarizing the land prepit signal on the valley side based on the slice level set by the subtraction means with respect to the radial push-pull signal. An optical disc device characterized by the above-mentioned.