JP2000200421A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect easily and surely a connecting point between a land track and a group track without lowering recording density by forming a binary differential signal from the differential signal of a photodetector, forming a discrimination signal gate signal from the differential signal, and detecting timing of a recording sector discrimination signal from the binary differential signal at the time of recording or reproduction of a disk medium. SOLUTION: When a light beam enters from an information recording part in a prescribed groove recording sector to the discrimination signal part of the next groove recording sector, a corresponding tracking error signal is outputted. Then, there is a discrimination signal part that is shifted by a half of the groove width in the inner periphery of a disk, a corresponding tracking error signal is outputted. By comparing the size of the two error signals, a servo can be controlled to the track center. Polarity information indicating whether the sector is the land sector or the group sector is contained in the discrimination signal other than the address of the sector, so that the polarity can be set by surely reading the discrimination information under normal tracking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus which records signals on both a recording track of a concave portion formed by a guide groove and a recording track of a convex portion formed between the guide grooves. is there.

[0002]

2. Description of the Related Art As a recording method for a large-capacity rewritable optical disk medium, both a groove portion (also referred to as a groove: G) and an inter-groove portion (also referred to as a land: L) are provided for improving recording density. A so-called land / groove recording method for recording data has been proposed. With a disk having the same groove pitch, the recording track pitch can be halved, so that the effect of increasing the density is great. The groove portion and the inter-groove portion may be referred to as a concave portion and a convex portion, respectively, depending on their shapes. As a conventional land / groove recording optical disk,
For example, Japanese Patent Application Laid-Open No. 63-57859 as shown in FIG.
Is described in Japanese Patent Application Publication No. As shown in FIG.
The groove 9 is formed by the guide groove formed on the disk substrate.
4 and a land portion 95 are formed, and a recording film 91 is formed thereon. The recording pits 92 are recorded on the recording films of both the groove portion 94 and the land portion 95. The groove portion 94 and the land portion 95 form continuous recording tracks on the disk. The focused spot 93 of the optical disk device for recording and reproducing the recording medium records / reproduces information while scanning either recording track. In the conventional land / groove recording format, since the guide groove is continuous on the disk, the recording track is continuous in both the groove portion 94 and the land portion 95, and each of the recording tracks is continuous.
It forms a record spiral for each book.

Next, the single spiral land / groove format will be described. FIG. 14 shows a recording track (hereinafter also referred to as a groove track) of a groove corresponding to one circumference of the disk and a recording track (hereinafter also referred to as a land track) of an inter-groove corresponding to one circumference of the disk provided between the grooves. 3) is a diagram showing a configuration of an optical disk having a format in which one recording spiral is formed by alternately connecting recording spirals. As an optical disk having a format as shown in FIG. 14 in which a recording track of a groove portion and a recording track of the inter-groove portion are alternately connected to form one recording spiral, for example,
There are those described in JP-A-38633 and JP-A-6-274896. Such an optical disk format is herein referred to as a single spiral land / groove format or an SS-L / G format. The SS-L / G format disc has a great feature that it is suitable for continuous recording and reproduction of data because recording tracks are continuous on the disc. For example, in video file applications, continuous recording and reproduction of data is essential. However, in the conventional land / groove recording as shown in FIG.
Since the land track and the groove track respectively constitute one recording spiral, for example, when recording and reproduction are continuously performed from the land track to the groove track, the land track and the groove track must be located at least at one place on the surface of the disk. The continuous recording / reproduction is interrupted by the access connecting to the track. The same applies to the case where recording and reproduction are continuously performed from the groove track to the land track. In order to avoid such interruption of recording / reproduction, it is necessary to add a buffer memory, which is a cost increase factor. However, if a single spiral land / groove format is used, this becomes unnecessary. On the other hand, SS-
In the L / G format, the polarity of the tracking servo must be switched once for one round of the disk, and it is difficult to detect the switching point, so that it is difficult to apply the tracking servo, and practical use has not been advanced. In fact, Japanese Patent Application Laid-Open Nos. 4-38633 and 6-274896 also disclose the use of the optical disk in the SS-L / G format, but do not provide a method for detecting a specific switching point. Is not disclosed.

In order to apply tracking servo to an SS-L / G format disk, a connection point where recording tracks in a groove portion and recording tracks in an inter-groove portion are alternately detected is detected, and the tracking servo polarity is detected there. It is necessary to switch the servo polarity between setting to track the recording track in the groove or setting to track the recording track in the groove. An example of a method of detecting a connection point where recording tracks in a groove portion and recording tracks in an inter-groove portion are alternately connected is disclosed in JP-A-6-290465.
And JP-A-7-57302. Japanese Unexamined Patent Publication No. 6-290465 discloses a method of providing irregularities at a fixed frequency at a connection point between a recording track in a groove portion and a recording track in an inter-groove portion. FIG. 15 shows a configuration of an optical disk recording medium described in the publication. Here, there are connection points at A1, A2, A3, B1, B2 and the like in FIG. Between each connection point of the groove and the groove, the groove,
Alternatively, the inter-groove portions are respectively continuous, and the positional information such as the track address is based on the wobbling of the groove. Japanese Patent Application Laid-Open No. 7-57302 discloses a method in which a flat portion having no groove or a predetermined bit pattern is provided at a connection point between a recording track in a groove portion and a recording track in an inter-groove portion. FIG. 16 shows a configuration of an optical disk recording medium described in the publication. (A) is an example in which a flat portion is provided at a connection point, and (b) is an example in which a predetermined bit pattern is provided. In this conventional example, there is no disclosure about position information such as a track address, and it is considered that the groove or the groove is continuous between the connection points of the groove and the groove.

A case where a recording track is composed of a plurality of recording sectors and bit pattern information for connection point detection is added to a disk having a sector format configuration in which unique identification information is added to each recording sector. Think. In the method of adding identification information by wobbling of the groove, there is no intermittent portion in the groove of the information recording portion, so that there is no problem of erroneous detection of a connection point. However, the function of sector recording is limited, for example, it is difficult to perform recording and reproduction in short sector units. On the other hand, when a format is adopted in which an information recording unit for recording preformatted identification information indicating an address and the like and user data is separately arranged on a recording track, as in a conventional ISO magneto-optical disk, In addition, there is a problem that the identification information and the connection point of the groove / inter-groove portion are erroneously detected as being represented in the same recording form. To avoid this, it is necessary to be able to reliably identify the identification information and the bit pattern for detecting the connection point between the groove and the groove.
In the example disclosed in Japanese Patent Application Laid-Open No. 7-57302, there is no place for a pit row as shown in FIG. However, when the identification information to be pre-formatted is arranged in the recording track in the same pit string pattern as the bit pattern for connection point detection, accurate bit synchronization is required to detect the connection point with accurate bit synchronization. It is necessary to reproduce the information.
This is common to the case where a connection point is detected based on a bit pattern, regardless of how the connection point is represented as a fixed frequency pattern or a predetermined pattern. In order to reproduce bit information with accurate bit synchronization, it is assumed that stable tracking is established, that is, the connection point between the groove and the groove is accurately detected and the tracking is switched. The premise of this is that, in order to achieve this, it is necessary to perform accurate bit synchronization and play back while discriminating the bit pattern for connection point detection and the identification information accurately. Become. This is because, in the conventional optical disk alone, a single spiral land / groove is used for an optical disc of a format in which a recording track is composed of a plurality of sectors and a preformatted identification information and an information recording section are separately arranged. This indicates that it is difficult to stably detect a connection point between a groove and a groove, which is essential for realizing a recording format.

Now, a description will be given of a method of inserting an identification signal prepit proposed in a conventional land / groove recording type optical disk. In a conventional land / groove recording method that is not a single spiral, there are three known methods for inserting identification signal prepits as shown in FIG. In the method shown in FIG. 17A, which is also called the land / groove independent address method, a unique sector address is assigned to each of the land track sector and the groove track sector. If the pit width representing the identification signal is the same as the groove width, the identification signal pre-pits of the adjacent track sectors are connected, and the signal cannot be detected. Therefore, the pit width of the identification signal is smaller than the groove width. , About half the groove width.
However, at this time, unless the beam diameters of the beam for cutting the prepit and the beam for cutting the groove are changed in the optical disc master making process, the groove and the prepit having different widths cannot be formed continuously. Therefore, the master must be cut using two beams, a groove cutting beam and a pit cutting beam. If the centers of the two beams are displaced, a tracking offset occurs during the reproduction of the identification signal prepit and during the recording / reproduction of the information recording signal, thereby deteriorating the quality of the reproduced data. Specifically, the error rate increases due to the deviation of tracking, and the reliability of data is reduced. For this reason, high precision is required for the alignment of the two beams, which causes an increase in cost in the disk master manufacturing process.

In consideration of such circumstances, the groove and the pit can be cut by one beam in view of the precision and cost of manufacturing the disk, or FIG.
The method shown in (c) is desirable. FIGS. 17B and 17C show a method of adding an identification signal prepit that can make the groove width and the prepit width substantially equal. FIG.
(B) is a conventional optical disk described in Japanese Patent Application Laid-Open No. 6-176404, which is also called a land / groove shared address system. This is a method in which prepits for identification signals are arranged near the center of a pair of adjacent groove tracks and land tracks, and the same identification signal prepits are shared by both tracks. Also, FIG.
This is a conventional optical disk described in Japanese Patent No. 82705, which is a time-division L / G independent address system. An independent address is added to each of the land track and groove track, provided that the positions of the pre-pits are shifted in the direction parallel to the tracks so that the pre-pits of the identification signal are not adjacent to each other. It is.

Another point to consider when considering a method of adding an identification signal and information for detecting a connection point is resistance to defects. When switching the tracking polarity by reading the identification signal or the information for detecting the connection point, the determination must not be erroneous due to a slight defect on the medium, and the groove and the inter-groove must not be mistaken. It is important not to erroneously detect a connection point with respect to a typical medium defect such as a minute scratch on a medium, a defective hole having a hole in a medium film and a decrease in reflectance.

Further, when considering a method of adding an identification signal or information for detecting a connection point, consideration must be given to servo characteristics in connection with the method. In the SS-L / G format, recording is performed on both lands and grooves, so that the track density is high. For this reason, if the tracking offset becomes large, the reproduction signal quality deteriorates due to crosstalk from an adjacent track, for example, an error rate increases due to an increase in jitter, and a cross erase occurs in which a part of the adjacent track is erased during recording. Or Since the error causing the tracking offset is generated in a combined manner in the optical head system, the track arrangement on the disk, and the servo circuit system, it generally occurs in the land track and the groove track in different sizes. In order to avoid crosstalk and cross-erase, it is necessary to perform offset compensation of different magnitudes for each track of land and groove. In the conventional land / groove method, that is, in a method in which one recording spiral is constituted by each of the groove track and the land track only, each land / groove track is recorded while the tracks are continuously tracked. The corresponding offset compensation was performed for a certain period of time, and the amount of compensation was maintained after the adjustment, so that the offset compensation could be easily performed.

However, in the SS-L / G format disk, the switching of the tracking polarity between the land track and the groove track must be performed at a high frequency of once per rotation of the disk. Need to be done. As described above, in the SS-L / G format, a method of adding an identification signal in consideration of tracking offset compensation is required.

In the above-described conventional method of inserting the identification signal into the land / groove recording, the method described above is required to cope with such a medium defect and to compensate for the tracking offset required for the SS-L / G format disk. The properties could not be met. For example, FIG.
In the case of the land / groove shared address system shown in FIG. 3B, during the reproduction of the identification signal, the pits are on only one side, so that the tracking offset is increasing. Also, in the case of the L / G independent addressing method as shown in FIG. 17C, the same applies to the case of FIG. 17B, but it is difficult to detect the tracking offset.

Next, points related to the drive operation of the optical disk will be described. Quick and accurate detection of the connection point between the groove and the groove becomes even more difficult when a control method in which the number of rotations of the disk changes while the optical disk is driven is applied. However, such a control method is mainly applied to an optical disc which is mainly used for video applications where continuous recording and reproduction of data is essential. The situation will be explained. When importance is placed on compatibility with a read-only optical disk in a rewritable optical disk, a phase change medium in which an optical system is easily shared with a read-only optical disk is suitable as a recording medium.
However, a phase change medium having recording / reproducing performance that can be practically used at present has a narrow range of recording linear velocities that can satisfy recording / reproducing characteristics when performing PWM recording. In particular,
Rotate the disk to CAV (Constant Angul)
In the case of (ar Velocity) control, the disk rotation speed at the inner circumference and the disk rotation speed at the outer circumference are the same, and the recording linear velocity at the outer circumference is increased from 2.5 times to 3 times the inner circumference. It is difficult for current media to cope with such a wide recording linear velocity. When the disk rotation is controlled by CAV, if the required data rate is fixed on the inner circumference to a required number of rotations, the outer circumference requires a signal processing circuit system to perform high-speed processing nearly three times the inner circumference, realizing low-cost hardware. Is difficult. Also, considering video applications, it is desirable that the data rate be constant at the inner and outer circumferences of the optical disc. Therefore, in a rewritable optical disk for digital video recording use, a ZCLV (Zone Constant) is required for two reasons: medium characteristics and circuit performance.
Linear Velocity), that is, the optical disc is divided into a plurality of zones in the radial direction, the number of revolutions of the disc is switched according to the zone, and the transfer rate is constant in all zones.
It is realistic to make the linear velocity almost constant. The problem here is that ZCLV requires switching the disk rotation speed when passing through the zone boundary, and when moving from one zone to another zone, the disk rotation speed is settled to the specified rotation speed of the newly shifted zone ( (Settling time) until it becomes stable), and the sector interval fluctuates during this time, and it is highly likely that the sector synchronization is temporarily lost, and it is necessary to quickly re-establish the sector synchronization. is there. At the same time, it is necessary to quickly and accurately detect the connection point between the land track and the groove track.

Further, a conventional land / groove recording type optical disk apparatus will be described. FIG. 18 is a block diagram showing a configuration of a conventional optical disk device described in Japanese Patent Application Laid-Open No. 6-176404. In FIG. 18, 100 is an optical disk, 101 is a semiconductor laser, 1
Numeral 02 denotes a collimating lens for converting the laser light from the semiconductor laser 101 into parallel light, 103 denotes a half mirror, 104 denotes an objective lens for condensing the parallel light passing through the half mirror 103 onto an optical disk, and 105 denotes an objective lens 104
Optical disk 100 having passed through and half mirror 103
This is a photodetector that receives the reflected light from the optical disk, and is divided into two parts in parallel with the track direction of the disk to obtain a tracking error signal, and is composed of two light receiving parts. Reference numeral 106 denotes an actuator that supports the objective lens 104, and the portion 107 surrounded by the dotted line is attached to the head base, and forms an optical head. 108 is a differential amplifier to which a detection signal output from the photodetector 105 is input, 109 is a tracking error signal from the differential amplifier 108, and a control signal T1 from a system control unit described later,
This is a polarity inversion unit that outputs a tracking error signal to the tracking control unit 110. Here, as for the polarity of the tracking control, when the tracking error signal is input from the differential amplifier 108 to the tracking control unit 110 with the same polarity, the tracking pull-in is performed on the recording track of the groove. Reference numeral 110 denotes a tracking control unit which receives an output signal from the polarity inversion unit 109 and a control signal T2 from a system control unit 121 described later and outputs a tracking control signal to a driving unit 120 and a traverse control unit 116 described later. 111 is a photodetector 105
The addition amplifier 112 receives the detection signal output from the amplifier and outputs a sum signal. The addition signal 112 receives the high-frequency component from the addition amplifier 111 and converts the digital signal into a reproduction signal processing unit 11 to be described later.
3 and a waveform shaping unit to be output to the address reproducing unit 114;
Reference numeral 13 denotes a reproduction signal processing unit that outputs reproduction data to an output terminal. An address reproducing unit 114 receives a digital signal from the waveform shaping unit and outputs an address signal to an address calculating unit 115 described later.
4 from the system control unit 121.
Is an address calculation unit which receives a control signal T1 from the controller and outputs an accurate address signal to the system control unit 121. Reference numeral 116 denotes a system control unit 12 described later.
A traverse control unit that outputs a drive current to a traverse motor 117, which will be described later, in response to a control signal T3 from
Reference numeral 7 denotes a traverse motor for moving the optical head 107 in the radial direction of the optical disc 100. A recording signal processing unit 118 receives recording data and outputs a recording signal to a laser (LD) driving unit 119 described later. A control signal T4 is output from a system control unit 121, and a recording signal is output from the recording signal processing unit 118. And a laser drive unit for inputting a drive current to the semiconductor laser 101. 1
A driving unit 20 outputs a driving current to the actuator 106. 121 outputs control signals T1 to T4 to a tracking control unit 110, a traverse control unit 116, an address calculation unit 115, a polarity inversion unit 109, a recording signal processing unit 118, and an LD drive unit, and inputs an address signal from the address calculation unit 115. This is the system control section.

The operation of the conventional optical disk device configured as described above will be described with reference to FIG. The laser light output from the semiconductor laser 101 is collimated by a collimator lens 102 and is split into a beam splitter 103.
Is converged on the optical disc 100 by the objective lens 104. The laser beam reflected by the optical disc 100 has information of a recording track, and the objective lens 104
Through the beam splitter 103 and the photodetector 105
Guided above. The photodetector 105 converts a change in the light amount distribution of the incident light beam into an electric signal, and outputs the electric signal to the differential amplifier 108 and the addition amplifier 111, respectively. Differential amplifier 10
Numeral 8 performs a current-voltage conversion (IV conversion) of each input current, calculates a difference, and outputs the difference as a push-pull signal. The polarity inverting unit 109 recognizes a track or land accessed by the control signal T1 from the system control unit, and inverts the polarity only when the track is a land, for example. The tracking control unit 110 outputs a tracking control signal to the driving unit 120 according to the level of the input tracking error signal, and the driving unit 120 supplies a driving current to the actuator 106 according to the signal to record the objective lens 104. Control the position across the track. Thus, the light spot scans the track correctly. On the other hand, the addition amplifier 111 performs current-to-voltage conversion (IV conversion) on the output current of the light receiving unit 105, adds the current, and outputs the sum to the waveform shaping circuit 112 as a sum signal. Waveform shaping circuit 1
Numeral 12 data slices the data signal and the address signal of the analog waveform with a certain threshold value to form a pulse waveform, and outputs the pulse waveform to the reproduction signal processing unit 113 and the address reproduction unit 114. The reproduction signal processing unit 113 demodulates the input digital data signal, and thereafter performs processing such as error correction and outputs the reproduced data. Address reproduction unit 114
Demodulates the input digital address signal and outputs it to the address calculation unit 115 as position information on the disk. The address calculation unit 115 calculates the address of the accessed sector based on the address signal read from the optical disc 100 and the land / groove signal from the system control unit 121. The calculation method will be described later. The system control unit 121 determines whether the current light beam is at a desired address based on the address signal. The traverse control unit 116 controls the control signal T from the system control unit 121 when the optical head is moved.
In response to 3, the drive current is output to the traverse motor 117 to move the optical head 107 to the target track. At this time, the tracking control unit 110 also temporarily suspends the tracking servo according to the control signal T2 from the system control unit 121. Also, during normal playback,
The traverse motor 117 is driven according to the tracking error signal input from the tracking control unit 110,
The optical head 107 is gradually moved in the radial direction as the reproduction progresses. The recording signal processing unit 118 adds an error correction code or the like to the recording data input during recording, and outputs the recording data to the LD driving unit 119 as an encoded recording signal.
When the system control section 121 sets the LD driving section 119 to the recording mode by the control signal T4, the LD driving circuit 119 modulates the driving current applied to the semiconductor laser 101 according to the recording signal. As a result, the intensity of the light spot irradiated on the optical disc 100 changes according to the recording signal, and recording pits are formed. On the other hand, at the time of reproduction, the LD driver 119 is set to the reproduction mode by the control signal T4, and controls the drive current so that the semiconductor laser 101 emits light at a constant intensity. This makes it possible to detect recording pits and pre-pits on the recording track.

In such a conventional optical disk device, the identification signal is reproduced as a sum signal based on the signal processed by the waveform shaping circuit 112. Even when an SS-L / G format disc is played, the connection point between the land track and the groove track is reproduced as a sum signal based on the signal processed by the waveform shaping circuit 112. Therefore, in order to accurately detect a connection point with high reliability, it is necessary to set at least an identification signal representing address information and the like and a bit pattern for connection point detection as considerably different ones. Even if the data or address is not ready for reproduction immediately after the tracking pull-in, the connection point must be detected. Therefore, the bit pattern for detecting the connection point must be reproducible even in an out-of-synchronization state. For this purpose, usually, a long bit number is allocated, and a prepit having a bit pattern of a low frequency, that is, a long pit is provided.
It is not advisable to allocate long bits to such a pattern in a large-capacity optical disk in which the redundancy is reduced as much as possible to improve the effective recording density.

[0016]

The conventional land / groove recording optical disk medium and the conventional optical disk apparatus are configured as described above. Therefore, the method of adding the identification signal to the single spiral land / groove recording format is applied as it is. In this case, there is a problem that it is difficult to accurately and accurately detect a connection point between a land track and a groove track. Further, if the connection point is separated from the identification signal into a bit pattern that can be easily detected, a long number of bits is required, and there is a problem that the effective recording density is reduced.

In the single spiral land / groove recording format, it is necessary to accurately perform tracking offset compensation in a short time, but there is a problem that it is difficult to detect the tracking offset.

The present invention has been made in order to solve the above problems, and has a single spiral land /
In a groove format optical disk, the connection point between a land track and a groove track can be easily and reliably detected without deteriorating the effective recording density, and the polarity of the tracking servo can be switched. It is an object of the present invention to obtain an optical disk device for driving an optical disk medium that can be performed accurately on time.

Further, when the single spiral land / groove format is applied to the ZCLV system in which the disk rotation speed and the number of sectors change in the zone, and the ZCAV system in which the number of sectors and the data frequency change according to the zone, the single spiral land / groove format is used. It is an object of the present invention to provide an optical disk apparatus for driving an optical disk medium capable of quickly reestablishing sector synchronization and improving an access speed.

[0020]

An optical disk device according to claim 1, wherein both the groove formed on the disk and the space between the grooves are used as an information recording section, and the information recording section is used as an information recording section. The information signal is recorded by causing a local optical constant change or a physical shape change due to the light beam irradiation, and the recording track of the groove corresponding to one round of the disk medium corresponds to one round of the disk medium. An optical disc medium in which recording tracks in the inter-groove portion are alternately connected to form one recording spiral, wherein the recording tracks are composed of an integral number of recording sectors of equal length, and An identification signal portion including an identification signal representing address information is arranged at the head portion so as to be aligned on the same radius as the identification signal portion of the adjacent recording sector,
The identification signal portion includes a first portion and a second portion, and the first portion is disposed so as to be displaced from the center of the groove portion or the inter-groove portion in one direction in the radial direction by a fixed amount. In an optical disc apparatus that records information on an optical disc medium that is disposed displaced by the same amount as the fixed amount in the other direction in the radial direction from the center of the groove or the space between the grooves or reproduces the recorded information, An optical head having a photodetector including a light receiving surface, a difference signal waveform shaping unit that generates a binarized difference signal from a difference signal of the photodetector, and an identification signal unit from the binarized difference signal. A reproduction difference signal processing unit that outputs a corresponding identification signal gate signal, and when recording or reproducing the optical disc medium, detects the timing of a recording sector identification signal from the waveform of the binary difference signal, Based on timing Characterized in that so as to ensure the sector synchronization.

According to a second aspect of the present invention, in the optical disk device, both the groove formed on the disk and the space between the grooves are used as information recording portions, and the information recording portion is irradiated with a light beam. An information signal is recorded by causing a local optical constant change or a physical shape change, and the recording track of the groove portion corresponding to one round of the disk medium and the recording of the inter-groove portion corresponding to one round of the disk medium are recorded. An optical disk medium in which tracks are alternately connected to form a single recording spiral, wherein the recording tracks are composed of an integral number of recording sectors of equal length, and the head of each recording sector has address information. Are arranged so as to be aligned on the same radius as the identification signal portion of the adjacent recording sector, and the identification signal portion includes a first portion and a second portion. A first portion is disposed displaced by a fixed amount in one radial direction from the center of the groove portion or the inter-groove portion, and the second portion is the other in a radial direction from the center of the groove portion or the inter-groove portion. In an optical disc device that records information on an optical disc medium arranged to be displaced by the same amount as the fixed amount in the direction of, or reproduces the recorded information,
An optical head having a photodetector including a light receiving surface divided into two parts, a difference signal waveform shaping section for generating a binary difference signal from a difference signal of the photodetector, and the identification signal from the binary difference signal A reproduction difference signal processing unit that outputs an identification signal gate signal corresponding to the discrimination unit, and when recording or reproducing the optical disk medium, determines the appearance timing of the identification signal of the next recording sector from the waveform of the binary difference signal. It is characterized by being estimated.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the drawings. Embodiment 1 FIG. The present embodiment relates to an optical disk medium of a single spiral land / groove recording (SS-L / G) format. In this embodiment, the optical disk medium is described as being divided into a plurality of zones by a circumferential boundary.

FIG. 1 is a diagram showing a track layout of the optical disk medium according to the first embodiment of the present invention, showing the arrangement of tracks and recording sectors in one zone and the configuration of recording sectors. As shown in the figure, tracks (groove tracks) of grooves (grooves and recesses) and tracks (land tracks) of lands and protrusions between grooves are alternately connected once for each rotation of the disk, and one recording is performed. A spiral (spiral (spiral) recording track) is formed. Here, it is assumed that the width of the groove portion is equal to the width of the inter-groove portion. That is, the groove width and the width between the grooves are equal to the track pitch, and are set to の of the groove interval.

One recording track is composed of an integer number of recording sectors, here, for example, 12 sectors. A preformatted identification signal section (identification signal area) is provided at the head of each sector. Is added. The difference from the conventional example is that the land track and the groove track are intermittent at the pre-pits of the identification signal part, in other words, they are connected via the pre-pits of the identification signal part. Holds (includes) the identification information for identifying the sector and also holds (includes) the information for detecting the connection point between the groove track and the track between the grooves. The recording sector forming the recording track includes an identification signal section preformatted at the head thereof and an information recording section capable of recording user data and various management information.

FIG. 2 is a schematic diagram for explaining the arrangement of pre-pits and their address values in the identification signal portion in the recording sector of the optical disk medium according to the first embodiment of the present invention. The identification signal part is a front part and a rear part in the scanning direction.
The front part is displaced from the groove part to the outer peripheral side by half of the groove width. The rear part is 1 / of the groove width from the groove.
It is displaced by two inward.

Next, a method of adding identification information such as a sector address in the identification signal portion will be described. Groove (in the figure,
Indicated as a recess. The address of ()) is added to the front identification signal portion of the groove portion, which is displaced from the center of the groove portion to the outer periphery by 1/2 of the groove width in the identification signal portion immediately before the information recording portion. In addition, the address of the inter-groove portion (shown as a protruding portion in the drawing) includes the center of the groove portion in the identification signal portion immediately before the information recording portion of one of the recording tracks on the outer peripheral side of the recording track of the inter-groove portion. Is added to the rear identification signal section which is displaced by 内 of the groove width toward the inner peripheral side. As a result, the address of the inter-groove portion is included in the identification signal portion immediately before the information recording portion in the rear identification signal portion of the groove portion which is displaced from the center of the inter-groove portion by half the groove width toward the outer peripheral side. It becomes the added form. Thus, the address of the inter-groove portion is not the inter-groove portion, but a shape added to the groove portion,
The identification signal portion in the groove portion does not include the identification signal.

The identification signal portion holds (contains) not only the sector identification information but also the sector address as well as the information on the tracking polarities of the sectors in each groove and between the grooves.

This is because the tracking offset generated during the cutting of the master disc is considered to be smaller when cutting the address of the groove and the address of the space between the grooves when cutting the recording track of the groove. From the tracking offset characteristics, if the tracking offset is smaller when cutting the groove address when cutting the recording track in the groove and cutting the address in the groove when cutting the recording track in the groove, separate them. You just need to cut.

The identification signal is を of the groove width from the track center.
The only displacement is that the identification information is shared between the groove track and the groove-to-groove track, so that almost the same quality of the identification information can be read when scanning either track. That's why. If the groove width is not equal to the track pitch, the amount of displacement may be １ ／ of the track pitch.

Next, a description will be given of the addition of pre-pits and addresses in the identification signal portion at the connection portion between the land and the groove, which is arranged once in one round of the disk in the radial direction of the disk. FIG. 3 is a schematic diagram for explaining the arrangement of the identification number prepits in the recording sector at the boundary between the land and the groove of the optical disc medium according to the first embodiment of the present invention and the address value thereof. In the SS-L / G format disk, there is a boundary line where the recording track of the groove portion and the recording track of the inter-groove portion are connected at one place in the radial direction. In the recording sector immediately after the connection point between the groove recording track and the inter-groove recording track, the arrangement of the identification signal of the identification signal portion is the same as the arrangement of the identification signal other than the boundary portion,
The front portion is displaced from the groove to the outer peripheral side by １ ／ of the groove width. The rear portion is displaced from the groove portion by の of the groove width toward the inner peripheral side. Addition of the address value is the same as that except for the boundary,
The address of the groove is added to the front identification signal portion which is displaced from the groove immediately before the information recording portion to the outer periphery by だ け of the groove width and arranged. Further, the address of the inter-groove portion is added to the rear identification signal portion which is displaced from the inter-groove portion immediately before the information recording portion toward the outer peripheral side by 1/2 of the groove width and arranged.

In order to detect a connection point (connection portion) between the recording track in the groove portion and the recording track in the inter-groove portion, in a state where tracking is performed, in the identification signal area, the first half and the second half are positioned with respect to the track center. To see if it is displaced inward or outward. Regarding the address of each sector, the identification information of the first half of the groove portion is shifted from the groove portion to the outer peripheral side by 1/2 of the groove width, and the sector of the groove portion is only 1/2 of the groove width from the groove portion. The address can be specified from the identification signal of the latter half which is displaced to the outer periphery. In each case, the portion displaced toward the outer periphery expresses the address of the own sector, and the portion displaced toward the inner periphery expresses the address of the sector adjacent to the inner periphery of one track.

Here, regarding the detection of the track connecting portion, the response when seeking is considered. At this time,
Immediately after passing through the zone boundary, the appearance interval of the preformat identification signal changes in a step-like manner, so that sector synchronization is easily lost. In the SS-L / G format, it is necessary to ensure that the land / groove switching point can be detected even in this case.

In the ZCLV, when seeking to a different zone, the identification signal is not detected at a predetermined time interval until the disk rotation speed is settled to the prescribed value for each zone, and the sector is out of synchronization. In such a case, with a normal L / G recording disk, tracking could be stably pulled in regardless of which land or groove track was applied. However, in the SS-L / G recording disk, if a land / groove switching point appears immediately after the tracking pull-in, tracking may be lost. Although the error occurrence probability of the tracking pull-in failure itself is low and can be recovered by retrying, it is desirable to reliably pull in the tracking even in such a case in order to improve the access speed and reliability.

According to the method of adding the identification signal to the SS-L / G recording disk shown in the first embodiment, as described above, the polarity can be reliably determined based on the order of the direction of the displacement of the identification signal. Can be used, the conventional SS-L /
It is possible to avoid such a tracking pull-in failure which tends to occur in the G recording disk.

As another function and effect, track offset correction will be described. Optical disc standard ISO / IEC 9171-1, 2 "130m
mOptical Disk Cartridge W
write Once for Information
As described in "Interchange", 1990., etc., in a sample servo type optical disk, a track offset detection pit pair is provided at a position displaced by a fixed amount from the track center on a recording track to the left and right, and a tracking offset amount is set. When a light beam passes through the middle of a track offset detection pit pair, the reproduced signal amplitude of the detection pit pair becomes equal.
Since the reproduction signal amplitude of the pit on one side increases and the reproduction signal amplitude of the pit on the other side decreases, the light beam passes through the center of the track by detecting and correcting the track offset amount of the light beam. Can be controlled as follows. In the present invention, the same principle and effect are
It can be incorporated into a single spiral land-groove recording format.

Now, it is assumed that the light beam enters the identification signal section (identification signal area) of the next groove recording sector from the information recording section (information recording area) in the specific groove recording sector. Since the head of the identification signal portion is shifted to the outer periphery of the disk by の of the groove width, a tracking error signal corresponding to that is output. After a while, this time, the groove width 1
Since there is an identification signal portion shifted by / 2, a tracking error signal corresponding to the identification signal portion is output. Ideally, if these two error signals are detected symmetrically, it means that the center of the track is scanned. Therefore, by comparing the magnitude of the tracking error signal detected from the identification signal portion which is arranged to be shifted between the inner circumference and the outer circumference, it becomes possible to control the servo around the track center. As described above, according to the method of adding the identification signal to the SS-L / G recording disk of the present invention, it is possible to simultaneously improve the servo characteristics.

As another function and effect, resistance to a medium defect will be described. For example,
Compared with the method of adding the identification signal already described with reference to FIG. 17B in the conventional example, the present invention maintains the difference signal at a certain high level for a certain period of time, and then maintains the difference signal at a low level for a certain period of time. A very difficult waveform
Since it is used to represent the connection point between the land track and the groove track and to represent the identification signal of the sector, it is almost erroneous to mistakenly detect a signal change caused by actual dust adhesion, medium defect, recording film deterioration, etc. Nothing. On the other hand, in the method of FIG. 17 (b), only a defect or the like at one location causes a change in the difference signal similar to that shown in the identification signal. Misunderstood. The present invention is much more excellent in terms of resistance to medium defects.

Further, another polarity discriminating method can be adopted. The identification signal contains, in addition to the address of the sector, polarity information indicating whether the sector is a land sector or a groove sector. Since identification information can be read reliably during normal tracking, it is of course possible to set the polarity according to this information. By using the above-described method of determining the polarity based on the direction and order of displacement of the identification signal and the polarity information in the identification signal, it is possible to more reliably and reliably set the tracking polarity.

As described above, the first portion, which is a part of the identification signal, is displaced from the center of the groove in one direction in the radial direction, for example, toward the outer periphery by a fixed amount, and the other portion of the identification signal is displaced. The second portion, which is a part, is arranged displaced from the center of the groove in the other radial direction, that is, for example, toward the inner side by the same amount as the fixed amount, and when reproducing the disc, a tracking error signal is generated. That is, the difference signal of the tracking sensor in the radial direction is binarized by two comparators having different threshold values, and the change is observed,
The tracking polarity of each recording sector can be determined, and the connection point between the land track and the groove track can be reliably detected.

Embodiment 2 This embodiment relates to an apparatus for recording and reproducing the optical disk medium described in the first embodiment. FIG. 4 is a block diagram showing a configuration of the optical disc device according to the first embodiment of the present invention. 4, 100 is an optical disk, 101 is a semiconductor laser, 10
2 is a collimating lens, 103 is a half mirror, 104
Is an objective lens, 105 is a photodetector, 106 is an actuator, 107 is an optical head, 108 is a difference signal detector, 10
9 is a polarity inversion unit, 110 is a tracking control unit, 111
Is an addition amplifier, 112 is a sum signal waveform shaping section, 113 is a reproduction signal processing section, 114 is an address reproduction section, 116 is a traverse control section, 117 is a traverse motor, 118 is a recording signal processing section, 119 is a laser drive section, and 120 is Is a drive unit. The above is basically the same as the conventional optical disk apparatus shown in FIG. 18, so that the same reference numerals as in the conventional example are used and the detailed description is omitted.

The configuration of the part different from that of FIG. 18 will be described. 1 is a difference signal waveform shaping section which slices an analog waveform tracking error signal from the difference signal detection section at an appropriate level and converts it into a digital value, and outputs a binary difference signal. A reproduction difference signal processing unit that extracts the identification signal, determines the tracking polarity, and outputs a polarity detection signal to the polarity control unit 8, the polarity information reproduction unit 4, the address reproduction unit 5, and the information reproduction unit 6. 8 is a reproduction difference signal processing unit 2
, A polarity detection signal and a control signal from the system control unit.
A polarity control unit that outputs a polarity setting signal and a control hold signal to 0. Reference numeral 3 denotes a reproduction signal processing unit which reproduces an identification signal containing address information and polarity information from a binary sum signal obtained by performing waveform processing on the sum signal, and 4 denotes a polarity indicating a tracking polarity of a sector from the identification signal. A polarity information reproducing unit for extracting information, an address reproducing unit 5 for reproducing sector address information from the identification signal, and an information reproducing unit 6 for reproducing user information recorded in an information recording unit on the disk. The reproduced polarity information and address information are sent to the system control unit and used for controlling the tracking polarity and the sample-hold state of the tracking control. Reference numeral 7 denotes a reproduction difference signal processing unit 2, a polarity information reproduction unit 4, and an address reproduction unit 5.
Information about the identification signal is input from the
The traverse control unit 116 is a system control unit that outputs control signals to the LD drive unit and the recording signal processing unit 118.

Next, the operation of the optical disk before and after the connection point between the track in the groove and the track in the groove will be described. FIG. 5 shows a procedure and method for performing tracking on the SS-L / G format disc shown in FIGS. 2 and 3.
Shown in FIG. 5A shows the arrangement of the identification signals that have been preformatted with the grooves. The first half portion of the identification signal of the groove portion has a track pitch of approximately 1 on the outer peripheral side with respect to the center of the groove.
When the second half is displaced inward from the center of the groove so as to be displaced by approximately 1/2 of the track pitch, the boundary sector connected to the land track / groove track is distinguished from the normal sector which is not. The signal arrangements are different as shown in FIG. 5A, as shown in FIGS. 2 and 3, respectively. 5 (a) to 5 (e) show the operation of the tracking system / identification signal detection system when passing near the preformat identification signal of the land / groove switching sector and other normal sectors, and the mechanism of land / groove switching. . (B) is a tracking error signal, (c) is a state of a control operation of a tracking servo system, (d) is an identification signal detection window signal, and (e) is read data of a preformat identification signal including tracking polarity information. . In order to explain the behavior of the tracking error signal when passing the identification signal portion, consider, for example, a light beam that is tracking a groove track. FIG. 5B shows a tracking error signal while this light beam is tracing on a recording track, that is, a state of a difference signal of the push-pull tracking sensor.

While the light spot is passing through the identification signal portion of a normal groove sector, the first half of the identification signal portion is displaced toward the outer periphery, so that the tracking error signal shows that the spot moves from the center of the groove to the inner periphery. A signal indicating approximately 1/2 track pitch displacement, that is, a signal indicating that the tracking error signal is displaced to the maximum is obtained. Also, since the latter half of the identification signal portion is displaced inward, the tracking error signal shows that the spot is displaced by approximately 1/2 track pitch from the center of the groove to the outer periphery, ie, the first half of the tracking error signal. And a signal indicating that the displacement is maximized in the opposite direction. As described above, the tracking error signal at the time of reproducing the identification signal portion indicates that the tracking is shifted to the inner periphery in the first half of the identification signal portion, and subsequently indicates that the tracking is shifted to the outer periphery in the latter half portion. Therefore, it can be determined that the recording sector following the identification signal portion is the recording sector of the groove track. The behavior of the tracking error signal in such an identification signal portion is common to sectors of any groove track.

Next, a change in a tracking error signal at a boundary where a groove track changes to a land track at a land / groove connection portion will be considered. In the identification signal portion of the land sector, the first half is displaced inward, and the second half is displaced outward. Therefore, in the tracking error signal, a tracking error signal indicating that the light spot is displaced by approximately 1/2 track pitch from the center of the groove toward the outer periphery in the first half of the identification signal portion appears, and the spot is shifted to the center of the groove in the second half. Approximately 1/2 from
A tracking error signal indicating that the track pitch is displaced appears. As described above, the tracking error signal at the time of reproducing the identification signal portion indicates that the tracking is shifted to the outer periphery in the first half of the identification signal portion, and subsequently indicates that the tracking is shifted to the inner periphery in the latter half portion. Therefore, it can be determined that the recording sector following the identification signal portion is the recording sector of the track in the groove. The behavior of the tracking error signal in such an identification signal portion is common to sectors of any land track. In the identification signal portion at the start end (head portion) of each track head sector, the polarity change of the tracking error signal is opposite to that of the head portion of the sector that has been traced so far. The tracking error signal passing through the identification signal section obtained in this way is converted into a binary signal by a comparator having two thresholds as shown by a dashed line in FIG.
It becomes possible to determine whether the sector is a land track or a groove track based on the polarity of the digitized signal.

It is to be noted that the tracking servo system is generally designed such that the band does not substantially respond when the length is about the identification signal portion. Even if a tracking error signal is generated between the identification signal portion and the trace, the tracking servo system does not respond. The light beam continues to trace the center of the track, that is, the side edge portion of the preformatted pit in the identification signal portion.
Alternatively, as a practical method, it is also possible to sample and hold a tracking error signal immediately before the identification signal section in order to cut off extra disturbance to the tracking servo system, and to pass the identification signal section by inertia with tracking control off. . FIG. 5C shows this state.

Reading of identification signal information such as a sector address is performed while sector synchronization protection is applied to an identification signal periodically appearing by an identification signal detection window signal as shown in FIG. 5D, and resynchronization is repeated each time. . Further, if information on the tracking polarity of the land / groove is prepared in the identification signal, the land / groove can be surely switched. Also, as described above, if the tracking error signal is gated using the identification signal detection window signal for sector synchronization protection and the error polarity is determined, land / groove switching appearing once in one round of the disk is performed. Points can be easily detected, and it is possible to improve the reliability of switching and setting of the tracking polarity in SS-L / G recording.

The procedure of the signal processing that is actually performed in the circuit block related to tracking and identification signal detection in the optical disk device in the above-described method for detecting the land / groove track connection point will be described. FIG. 6 shows a difference signal detection unit 108, a difference signal waveform shaping unit 1, and a reproduced difference signal processing unit 2.
The block configuration of FIG. FIG. 7 shows a change in each signal during tracking of the recording track. Difference signal detection unit 10
In the differential input amplifier constituting No. 8, the difference between the two output signals of the two-divided photodetector 105 is obtained and output as a difference signal used for a push-pull tracking servo system. The difference signal is binarized by the difference signal waveform shaping unit 1. At this time, in order to detect that the pre-pit is displaced to the left and right with respect to the traveling direction of the light beam by ト ラ ッ ク of the track pitch in the identification signal portion, the threshold value is set to Lth and Rth by the comparator, respectively. Prepare the level,
A binary signal L0 indicating that the tracking of the light beam is displaced to the left (inner peripheral side) with respect to the trace direction in FIG.
And a binarized signal R0 indicating displacement to the right (outer peripheral side). If the difference signal level is equal to or higher than Lth, L0
Is Hi, and L0 is Lo if less than Lth. If the difference signal level is lower than Rth, R0 is Hi;
0 becomes Lo. The state of L0 and R0 is shown in FIG.
As shown in FIG. The set values of Lth and Rth are
For example, the level of the tracking error is set to the level of the difference signal corresponding to the 1/4 track pitch. If the set value is too small, there is a risk of erroneous detection when tracking deviation occurs due to disturbance, and if it is too large,
Since there is a possibility that the displacement of the identification signal may be overlooked due to a change in the reflectance due to the attachment of dust to the disk surface, an appropriate value is set during that time. As shown in FIG. 7, the center of the amplitude of the identification signal may be used.

The binary difference signal is digitally processed by the reproduction difference signal processing section 2 and outputs a polarity discrimination signal indicating whether the sector is a land sector or a groove sector. At the same time, a detection gate signal for estimating the appearance interval of the identification signal is also generated. The circuit of the reproduction difference signal processing unit, as shown in FIG.
It consists of a delay circuit and a decision circuit. Since the identification signal is intermittently modulated by information in the groove and is in the form of a pit row, the two binary difference signals L0 and R0 are also waveforms modulated by the data signal frequency. In the delay circuit, the input 2
For each of the two binarized difference signals L0 and R0, it is monitored whether or not the pulse train obtained by reproducing the pit train continues for a certain period of time: t1 or more, as shown in FIGS. 7 (e) and (f).
When the predetermined time: t1 or more has elapsed, an L detection signal: L1 and an R detection signal: R1 are output, respectively. Each of L1 and R1 is given a pulse width t3 so that it is at least Hi between the identification signal portions. The length of t1 is set as long as possible within a range shorter than the length corresponding to the identification signal portion in view of a certain margin for the linear velocity fluctuation of the disk so that it can be distinguished from other noise such as a medium defect.

In the identification signal of the groove sector, a pulse train continues at L0 for at least t1 and then at R0 a pulse train continues for at least t1. Therefore, when the first half and the second half of the identification signal are normally recognized, when R1 rises from Lo to Hi, L1 is in the Hi state. Note that L1 is Lo
R1 is still in the Lo state when the signal rises to Hi. Here, L1 is latched at the rising edge of R1 to generate a signal GP as shown in FIG.
R1 is latched at the rising edge of, and a signal LP as shown in FIG. In the identification signal of the groove sector, when the first half and the second half of the identification signal are recognized, GP is in the Hi state and LP is in the Lo state. On the other hand, in the land sector identification signal, first, a pulse train follows R0 for t1 or more, and then a pulse train follows L0 for t1 or more.
Therefore, when the first half and the second half of the identification signal are normally recognized, when L1 rises from Lo to Hi, R1 is already in the Hi state. R1 is Lo to Hi
L1 is still in the Lo state. That is, in the identification signal of the land sector, when the first half and the second half of the identification signal are recognized, LP is in the Hi state, G is
P is in the Lo state. Thus, LP is a land polarity detection signal, and GP is a groove polarity detection signal. Either of these two polarity detection signals is detected from the identification signal of each recording sector.

After the time corresponding to the length of the information recording portion of the sector has elapsed since the rise of either LP or GP, the identification signal of the next sector appears. The two polarity detection signals are:
The state is reset to the Lo state immediately before the identification signal of the next sector. This reset processing is performed at the rising edge of a signal represented by an identification area detection gate signal: IDG in (i) of FIG. IDG is a signal for estimating the time from the detection of the identification signal of one sector to the identification signal of the next sector,
Time when the polarity detection signal is reset to the Lo state when it becomes the Hi state, and immediately before the appearance of the identification signal of the next sector:
The state becomes Hi after elapse of t5. During normal sector synchronization and tracking while reading the identification signal, I
Since the identification signal appears during the period when DG is Hi, there is a function of a prediction gate signal for detecting the identification signal by removing noise appearing in the difference signal during the period when IDG is Lo. In this manner, during tracking, the presence of the identification signal and the direction of displacement of the identification signal are detected only by the difference signal, and whether the sector is a land sector or a groove sector can be detected based on the direction and order of the displacement. it can. According to this method,
Since it is determined for each sector whether or not a connection point between a groove portion and a groove portion of a recording track appears, reliable detection can be realized.

When the identification signal is out of synchronization, that is, when the sector is out of synchronization, the identification area detection gate signal: IDG is in the Hi state. Therefore, if the identification signal is included in the binarized signal waveform, the above explanation will be made. As is clear from FIG. 5, it is possible to quickly establish the sector synchronization by detecting the timing of the identification signal. At this time, since the identification signal is detected by the difference signal, a signal having a large level appears in the difference signal after tracking pull-in, in a portion other than the identification signal, regardless of whether or not data is recorded in the information recording unit. Never. This can be understood from the fact that the tracking error signal is scarce during the normal operation of the tracking servo. Therefore, the feature that the identification signal can be easily detected can be recognized.

Next, the operation of the polarity control unit will be described. FIG. 8 shows the configuration of the polarity control unit 8. The polarity control unit 8 receives the polarity detection signals Gp and Lp, sends a polarity setting signal LGSET for specifying the tracking polarity to the polarity inversion unit 109, and controls the tracking control unit 110 to continue / hold the control. Has a function to send HOLD. Turn on tracking in the device control sequence
Since a signal (TS control signal) from the system control unit is also received for the / OFF operation, these are collectively determined to determine the tracking polarity and the control operation. FIG.
8A shows a circuit block of the polarity control unit 8, and FIG.
(B) shows the states of the two polarity detection signals and the identification area detection gate signal IDG, and examples of setting the tracking polarity in each state. In a state in which the identification signal is normally detected, when one of the polarity detection signals GP and LP is Hi, H
The polarity may be set to the i-side polarity. In other cases, it is convenient to control the device by setting the default state.
Groove polarity is set. When the tracking polarity setting signal LGSET is Hi, the land is tracked, and when it is Lo, the groove is tracked. However, when entering the identification signal portion, a HOLD signal is sent to the tracking control section 110 to temporarily stop the tracking control. In FIG. 5C, three tracking control states of land / groove / stop are represented by one signal level.

Embodiment 3 Another embodiment of the present invention will be specifically described with reference to the drawings. FIG. 9 shows another block configuration of the reproduction difference signal processing unit 2. The change of each signal during tracking the recording track is the same as that shown in FIG. The process from the output of the two-segment photodetector 105 to the output of the binary difference signal is the same as in FIGS. Here, as shown in FIG. 9, the reproduction difference signal processing section 2 is composed of two blocks of a counting circuit and a determination circuit. Since the discrimination signal is intermittently modulated by information in the groove and is in the form of a pit row, the two binarized difference signals L0 and R0 from the difference signal waveform shaping unit 1 are also modulated by the data signal frequency. It is a waveform of a pit row.
In the counting circuit, the two input binary difference signals L0, R
For each of 0, a fixed time: t2 (t2> t1)
It is monitored whether a predetermined number or more of pulses appear in the binarized difference signal within a predetermined time.
The detection signal: L1 and the R detection signal: R1 are output. L1,
A pulse width t3 is given to R1 so that it is at least Hi during tracing the identification signal portion. As in the example described in the second embodiment, the length of t1 can be discriminated from other noises such as a medium defect within a range shorter than the length corresponding to the identification signal portion, with some allowance for the linear velocity fluctuation of the disk. Set as long as possible. Since the identification signal section contains a prescribed number of preformat data defined in the format, each of the first half and the second half of the identification signal section contains a certain number or more of pulses. For detection of the identification signal, provided that a certain number or more pulses are input within a specified time,
An identification signal can be detected. In the circuit shown in FIG. 9, L0 is input to the UP input of the up / down counter, a determination period t2 is applied to the DOWN input, and a clear signal for removing a noise pulse is input. Specifically, a slow clock signal may be used. In the up / down counter, in the identification signal portion, the pulse input to L0 counts up to a specified number of pulses, and outputs Hi to L1. L1 remains Hi for a time t3, and is reset by a t3 timer when t3 has elapsed. The t3 timer is a circuit that clears (resets) the up / down counter after time t3 when Hi is input from L1. To the other up / down counter, L0 is input to the UP input of the up / down counter, a determination period t2 is given to the DOWN input, and a clear signal for removing noise pulses is input. The operation outputs R1 in the same manner as the up / down counter to which L0 is input. Hereinafter, the determination circuit determines L1 and R1 and determines the polarity detection signal Gp as in the example described in the second embodiment.
And Lp. Recognition and determination of the identification signal of the groove sector or the land sector can be performed in the same manner as in the first embodiment.

Embodiment 4 Another embodiment of the present invention will be specifically described with reference to the drawings. FIG. 10 shows a difference signal detection unit 108, a difference signal waveform shaping unit 1, and a reproduced difference signal processing unit 2.
3 shows another block configuration. FIG. 11 shows a change in each signal during tracking of the recording track. 2-split detector 10
5 to the output of the binary difference signal are the same as those in FIGS. As shown in FIG. 10, the reproduction difference signal processing unit 2
Is composed of three blocks: a correction circuit, a delay circuit, and a determination circuit. Since the discrimination signal is intermittently modulated by information in the groove and is in the form of a pit row, the two binarized difference signals L0 and R0 from the difference signal waveform shaping unit 1 are also modulated by the data signal frequency. It is a waveform. The correction circuit uses a retriggerable mono-multi vibrator or the like, for example, in order to detect the presence or absence of the first half and the second half of the identification signal from the two input binary difference signals. Thus, the waveform is corrected so that each of the first half and the second half of the identification signal becomes one continuous pulse. L0
To correct the binarized correction difference signal L2 and R0 to
A value correction correction difference signal R2 is generated. In the delay circuit, for each of the two binary difference signals L2 and R2 input as in the example described in the first embodiment, it is monitored whether or not the pulse train obtained by reproducing the pit train continues for a certain time: t1 or more. , A fixed time: when the time has continued for t1 or more,
A detection signal: L3 and an R detection signal: R3 are output. L3,
A pulse width t3 is given to R3 so that it becomes Hi at least between the identification signal portions. Hereinafter, recognition and determination of the identification signal of the groove sector or the land sector can be performed in the same manner as in the second embodiment.

Embodiment 5 Still another embodiment of the present invention will be specifically described with reference to the drawings. FIG. 12 shows an example in which the frequency characteristics of the difference signal detection unit 108 are limited to simplify the processing in the difference signal waveform shaping unit 1 described in the third embodiment. In the tracking control system, usually,
It is only necessary to detect the difference signal in the servo control band. Therefore, an inexpensive amplifier with a narrow band can be used as the differential input amplifier for detecting the difference signal. The discrimination signal is intermittently modulated by information in the groove, and is in the form of a pit row. In this case, the difference signal waveform is subjected to low-pass filtering as shown in FIG. It is a waveform that has been transformed. Hereinafter, the processing in the reproduction difference signal processing unit 2 does not require a correction circuit in the block in the third embodiment, and the binarized correction difference signal can be directly handled in the same manner as L2 and L3 in FIG. it can. Subsequent processing is the same as in the third embodiment.

In Embodiments 2 to 5,
The operation of mainly determining the direction and order of displacement of the identification signal from the difference signal of the tracking sensor output signal and thereby determining the tracking polarity has been described, but the polarity information in the identification signal is determined from the sum signal of the tracking sensor output signal. By reproducing by the polarity information reproducing unit 4 and using it together with the tracking polarity discrimination result obtained from the difference signal,
Further, the tracking polarity can be set more reliably and more reliably.

Further, the identification signal and the method of detecting the track connection point shown in each of the above embodiments are merely examples for explaining the present invention, and the same functions can be realized by various circuit configurations. Needless to say, the present invention is not limited to the above embodiments.

[0058]

Since the present invention is configured as described above, it has the following effects.

In the optical disk apparatus according to the first aspect of the present invention, the detection of the sector synchronization is made quicker, more accurate, and easier for the optical disk of the single spiral land / groove recording, so that the land track and the groove can be obtained. The connection point of the track can be reliably and easily detected. In the ZCLV system in which the number of disk revolutions and the number of sectors change in each zone, sector synchronization after passing through a zone boundary can be quickly re-established, so that the effect is remarkable and the access speed can be improved. Even in the ZCAV system in which the number of sectors and the data frequency change depending on the zone, sector synchronization after passing through the zone boundary can be quickly re-established, so that the effect is remarkable and the access speed can be improved.

In the optical disk apparatus according to the second aspect of the present invention, the time from the detection of the identification signal of one sector to the identification signal of the next sector is estimated for an optical disk of single spiral land / groove recording. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a track layout of an optical disc medium according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram for explaining an arrangement of an identification signal in a recording sector of the optical disk medium according to the first embodiment of the present invention and its address.

FIG. 3 is a schematic diagram for explaining the arrangement of identification numbers in recording sectors and their addresses at boundaries between lands and grooves of the optical disc medium according to the first embodiment of the present invention; .

FIG. 4 is a block diagram illustrating a configuration of an optical disc device according to a second embodiment of the present invention;

FIG. 5 is a timing chart for explaining a method of recognizing the tracking polarity of a recording sector according to the second embodiment of the present invention;

FIG. 6 is a circuit block diagram of a reproduction difference signal processing unit of the optical disc device according to the second embodiment of the present invention.

FIG. 7 is a detailed timing chart illustrating a method of recognizing the tracking polarity of a recording sector according to the second embodiment of the present invention.

FIG. 8 is a diagram illustrating circuit blocks and functions of a polarity control unit of the optical disc device according to the second embodiment of the present invention.

FIG. 9 is a circuit block diagram of a reproduction difference signal processing unit of the optical disc device according to the third embodiment of the present invention.

FIG. 10 is a circuit block diagram of a reproduction difference signal processing unit of an optical disc device according to a fourth embodiment of the present invention.

FIG. 11 is a detailed timing chart illustrating a method for recognizing the tracking polarity of a recording sector according to the fourth embodiment of the present invention.

FIG. 12 is a detailed timing chart illustrating a method of recognizing the tracking polarity of a recording sector according to the fifth embodiment of the present invention.

FIG. 13 is a diagram showing an example of a conventional land / groove recording optical disk.

FIG. 14 is a diagram showing an example of a conventional optical disk having a single spiral land / groove recording format.

FIG. 15 is a diagram showing an example of land / groove connection points of a conventional single spiral land / groove recording optical disc.

FIG. 16 is a diagram showing another example of a land / groove connection point of a conventional single spiral land / groove recording optical disc.

FIG. 17 is a diagram showing a layout of identification signals in a conventional land / groove recording method.

FIG. 18 is a block diagram illustrating a configuration of a conventional optical disc device.

[Explanation of symbols]

1 difference signal waveform shaping section, 2 playback difference signal processing section, 3 playback signal processing section, 4 polarity information playback section, 5 address playback section, 6 information playback section, 7 system control section, 8
Polarity control unit, 91 recording film, 92 recording pits, 93
Focusing spot, 94 groove, 95 land, 1
00 optical disk, 101 semiconductor laser, 102 collimating lens, 103 half mirror, 104 objective lens, 105 photodetector, 106 actuator,
107 optical head, 108 differential amplifier, 109 polarity inverting section, 110 tracking control section, 111 addition amplifier, 112 waveform shaping section, 113 reproduction signal processing section,
114 address reproducing unit, 115 address calculating unit, 1
16 traverse control unit, 117 traverse motor,
118 recording signal processing unit, 119 laser driving unit, 12
0 Drive unit, 121 system control unit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masato Nagasawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Kenji Goshima 2-3-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Yoshinobu Ishida 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Sanishi Electric Co., Ltd.

Claims (2)

[Claims] An information recording portion includes a groove formed circumferentially on a disk and an inter-groove portion between the grooves, and a local optical constant change or physical change caused by irradiation of the information recording portion with a light beam. An information signal is recorded by causing a shape change, and the recording tracks of the groove portions corresponding to one round of the disk medium and the recording tracks of the inter-groove portions corresponding to one round of the disk medium are alternately connected to each other. An optical disc medium on which a recording spiral is formed, wherein the recording track is composed of an integer number of recording sectors having the same length, and an identification signal including an identification signal representing address information is provided at a leading portion of each recording sector. Are arranged so as to be aligned on the same radius as the identification signal portion of the adjacent recording sector, wherein the identification signal portion includes a first portion and a second portion, and the first portion has a groove portion. Or the second portion is displaced from the center of the inter-groove portion in one radial direction by a fixed amount, and the second portion is displaced from the center of the groove portion or the inter-groove portion by the same amount in the other radial direction. An optical disk device for recording information on an optical disk medium arranged and reproducing the recorded information, comprising: an optical head having a photodetector including a light receiving surface divided into two parts; and a difference signal from the photodetector. A difference signal waveform shaping section for generating a binary difference signal; and a reproduction difference signal processing section for outputting an identification signal gate signal corresponding to the identification signal section from the binary difference signal. An optical disk device, wherein when recording or reproducing, the timing of a recording sector identification signal is detected from the waveform of the binary difference signal, and sector synchronization is ensured based on the detected timing. 2. A method according to claim 1, wherein both the groove formed circumferentially on the disk and an inter-groove between the grooves are used as an information recording portion, and a local optical constant change or physical change caused by irradiation of the information recording portion with a light beam. An information signal is recorded by causing a shape change, and the recording tracks of the groove portions corresponding to one round of the disk medium and the recording tracks of the inter-groove portions corresponding to one round of the disk medium are alternately connected to each other. An optical disc medium on which a recording spiral is formed, wherein the recording track is composed of an integer number of recording sectors having the same length, and an identification signal including an identification signal representing address information is provided at a leading portion of each recording sector. Are arranged so as to be aligned on the same radius as the identification signal portion of the adjacent recording sector, wherein the identification signal portion includes a first portion and a second portion, and the first portion has a groove portion. Or the second portion is displaced from the center of the inter-groove portion in one radial direction by a fixed amount, and the second portion is displaced from the center of the groove portion or the inter-groove portion by the same amount in the other radial direction. An optical disk device for recording information on an optical disk medium arranged and reproducing the recorded information, comprising: an optical head having a photodetector including a light receiving surface divided into two parts; and a difference signal from the photodetector. Recording the optical disc medium, comprising: a difference signal waveform shaping section that generates a binary difference signal; and a reproduction difference signal processing section that outputs an identification signal gate signal corresponding to the identification signal section from the binary difference signal. Alternatively, at the time of reproduction, an appearance timing of an identification signal of a next recording sector is estimated from a waveform of the binary difference signal.