JP2002245637A - Optical disk, and method and device for optical disk recording and reproduction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize an optical disk which can have its rotating speed accurately controlled and can have its preformat information accurately detected even when the track pitch is narrow. SOLUTION: Positions on grooves 1, where a synchronous mark 3 formed on the optical disk for detecting a synchronous signal which controls the rotating speed of the disk and a pre-mark 4 for detecting the preformat information including address information for position retrieval are displayed, are displaced from the position of the center line to the side of one land 2. Further, the synchronous mark 3 is made shorter than the pre-mark 4. Otherwise, the grooves 1 as the synchronous mark 3 and pre-mark 4 are displaced toward the respectively different lands 2. In this case, the displacement quantity of the synchronous mark 3 and pre-mark 4 is <=1/4 times as large as track pitch intervals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk on which information can be written, an optical disk recording / reproducing method, and an optical disk recording / reproducing apparatus.

[0002]

2. Description of the Related Art In a writable and recordable optical disk,
Address information for position search and synchronization pattern for adjusting the number of rotations of the disk (hereinafter, address information and synchronization pattern are collectively referred to as preformat information)
Are previously formed on the optical disk. A method for recording the preformat information is disclosed in
As a pre-pit described in Japanese Patent No. 1470,
Alternatively, recording is performed by wobbling a groove used in a CD-R (Compact Disc-Recordable). In JP-A-6-231470, an area in which the preformat information is recorded and an area in which the information is recorded are formed separately.

In the CD-R, grooves are wobbled in a radial direction, and address information is given by modulating a wobble frequency by a certain method. If the wobble frequency is set to a frequency higher than the trackable frequency of the optical disk recording / reproducing device, the light spot does not follow the wobble frequency, so that a wobble frequency component is superimposed on the tracking error signal, and the address is detected by detecting the wobble signal. Information is obtained.

[0004]

In recent years, there has been a demand for further increasing the capacity of optical discs, and it is necessary to narrow the track pitch in order to improve the recording density. For this reason, there is a problem of accurately reproducing preformat information even at a narrow track pitch.

However, in JP-A-6-231470, the preformat area where preformat information is recorded is separated from the data recording area where data is recorded, so that the recording capacity of the optical disc is reduced. Problem. Also, in this method,
Since the recorded data becomes discontinuous, there is a problem that it is difficult to make the same format as a CD-ROM disc on which data is continuously recorded.

On the other hand, in the groove wobble method used for the CD-R, when the track pitch is narrowed, the amplitude of the wobble signal becomes small, so that the preformat information cannot be accurately reproduced. The present invention has been made to solve the above problems,
An object of the present invention is to provide an optical disk, an optical disk recording / reproducing method, and an optical disk recording / reproducing apparatus which can achieve the following objects.

(1) An object of the present invention is to realize an optical disk capable of accurately controlling the number of rotations of an optical disk and accurately detecting preformat information even at a narrow track pitch.

(2) An object of the present invention is to realize an optical disk that can easily identify and detect a synchronization mark and a premark.

(3) An object of the present invention is to realize an optical disk capable of reproducing each mark even when a synchronization mark and a premark are formed side by side in the radial direction.

(4) An object of the present invention is to realize an optical disc capable of reliably detecting a synchronization mark or a pre-mark and accurately reproducing recorded information.

(5) An optical disk capable of recording object information at an accurate position according to claims 6 and 9 is realized.

(6) An object of the present invention is to realize an optical disk capable of continuously recording information on the optical disk.

(7) An object corresponding to claim 10 An optical disk recording / reproducing method for recording / reproducing information on / from the optical disk of claims 1 to 9 is provided.

(8) Object corresponding to claim 11 An optical disk recording / reproducing apparatus for recording / reproducing information on / from the optical disk according to claims 1 to 9 is realized.

[0015]

According to a first aspect of the present invention, there is provided a recordable optical disk having a spirally formed groove, the preformat information having address information for position search, and the rotational speed of the disk. The optical disk is characterized in that the optical disc has pre-marks and synchronization marks in which the grooves are displaced to one of the lands as the information for controlling.

According to a second aspect of the present invention, in the optical disk of the first aspect, the synchronous mark length is shorter than the pre-mark length.

According to a third aspect of the present invention, in a recordable optical disk having a spirally formed groove, a premark in which the groove is displaced to one of the lands as preformat information is formed. The optical disk is characterized in that the optical disk has a synchronous mark formed by displacing it in a direction opposite to the premark as information for controlling the number of revolutions.

According to a fourth aspect of the present invention, in the optical disk according to the third aspect, the displacement of the pre-mark and the synchronization mark is equal to or less than 1/4 of a track pitch interval. It is.

The invention according to claim 5 provides the invention according to claims 1 to 4
Wherein the length Ls of the synchronization mark is 2T <Ls <14T, where T is a unit of the length of a recording mark recorded on the optical disk. Is what you do.

The invention according to claim 6 is the invention according to claims 1 to 5
The optical disk according to any one of the above, wherein a plurality of the synchronization marks are formed in a sector.

The invention according to claim 7 is the invention according to claims 1 to 6
Wherein the length Lp of the pre-mark is 2T <Lp <14T, where T is a unit of the length of a recording mark recorded on the optical disk. Things.

The invention described in claim 8 is the first to seventh aspects of the present invention.
Wherein the preformat information is recorded in an address sector, and the address sector is an optical disk including a plurality of sectors.

The ninth aspect of the present invention provides the first to eighth aspects.
The optical disk according to any one of the above, wherein the preformat information includes at least a synchronization pattern, address data, and error correction code data.

According to a tenth aspect of the present invention, in the optical disk recording / reproducing method for recording / reproducing information on / from the optical disk according to any one of the first to ninth aspects, the rotational speed of the optical disk is determined by a synchronous mark signal detected from the synchronous mark. And an optical disk recording / reproducing method for detecting the synchronization mark signal and the premark signal with one beam spot by a push-pull method when detecting a position on the optical disk by a premark signal detected from the premark. Things.

According to an eleventh aspect of the present invention, in the optical disk recording / reproducing apparatus for recording / reproducing information on / from the optical disk according to any one of the first to ninth aspects, a detecting means for detecting the synchronization mark; Control means for controlling the number of rotations of the optical disc from a mark, detecting means for detecting the premark, and detecting means for detecting a position on the optical disc from the detected premark, wherein the synchronization mark and the premark The optical disc recording / reproducing apparatus is based on a push-pull method in which each of the detecting means detects one beam spot.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical disk according to the present invention will be described below with reference to the drawings. First,
A first embodiment of the optical disc according to the present invention will be described. The optical disc according to the present embodiment is characterized in that a synchronization mark and a premark are formed by displacing a groove in a radial direction, and high-density recording is performed by a synchronization mark signal and a premark signal obtained from these marks. Is what makes it possible. The synchronization marks are formed at predetermined intervals, and the length of the synchronization marks is shorter than that of the pre-marks so that the synchronization marks can be distinguished from the pre-marks.

The optical disk of the present embodiment will be described with reference to FIG. Here, FIG. 1 is a conceptual diagram for describing a first embodiment of the optical disk according to the present invention, and FIG. 1A is an enlarged plan view of the optical disk,
FIG. 1B shows a push-pull signal (P) when the light spot reproduces, for example, the m-th groove Gr (m).
(P signal).

As shown in FIG. 1A, grooves 1 are formed at track pitch intervals TP,
The pre-mark 4 is formed by displacing the groove 1 toward the outer periphery. However, synchronization mark 3 is premark 4
It is shorter. Also, as shown in FIG. 1B, when the light spot is at the center of the groove 1, no push-pull signal (PP signal) is generated, but at the position where the synchronization mark 3 is located, the cross-sectional shape in the radial direction is reduced. Since it is asymmetric with respect to the center of the groove 1, a push-pull signal (PP signal) is generated. A signal generated by the synchronization mark 3 is detected as a synchronization mark signal.

On the other hand, a push-pull signal (PP signal) is also generated at the position where the premark 4 is located. However, since the mark length is longer than the synchronization mark 3, the frequency of the premark signal by the premark 4 is And lower than the frequency of the synchronization mark signal. Therefore, if such a push-pull signal (PP signal) is passed through a filter adapted to the frequency of each of the synchronization mark signal and the premark signal, the synchronization mark signal and the premark signal can be easily detected.

FIG. 3 is a diagram showing an example of preformat information recorded on an optical disc according to the present invention. As shown in FIG. 3A, one address sector includes a plurality of sectors, and preformat information is recorded as a premark in each of the plurality of sectors. That is, FIG.
As shown in (F), the premark is formed only at the head of each sector, corresponding to the information 0 and 1 and the synchronization pattern, respectively. Therefore, the premarks are dispersedly recorded in one address sector. Note that the synchronization pattern is the head of the address sector, and indicates that address data and the like are recorded thereafter.

On the other hand, as shown in FIG. 3C, a plurality of synchronization marks are recorded at predetermined intervals in each sector. At the time of recording / reproducing of the optical disk, the rotation speed of the optical disk is controlled so that the synchronization mark signal appears at a predetermined frequency. In addition, if data of an error correction code is added as premarks in addition to address data as preformat information, even if the address data is incorrect or erroneously read, it can be corrected to some extent. Thus, the address data can be correctly detected.

Next, a second embodiment of the optical disk according to the present invention will be described. Synchronization marks are formed at predetermined intervals in the same manner as in the first embodiment, but the synchronization marks are formed by being displaced in the direction opposite to the premarks, and are easily distinguished from the premarks. Can be detected separately. Regarding the optical disc of the present embodiment,
This will be described with reference to FIG. Here, FIG. 2 is a conceptual diagram for explaining a second embodiment of the optical disk according to the present invention, FIG. 2 (A) is an enlarged plan view of the optical disk, and FIG. The light spot shows a state of a push-pull signal (PP signal) when, for example, the m-th groove Gr (m) is reproduced.

As shown in FIG. 2A, the grooves 1 are formed at track pitch intervals TP, and the synchronization marks 3
Is formed by displacing the groove 1 toward the outer periphery. On the other hand, the premark 4 is formed by displacing the groove 1 inward.

A push-pull signal (PP signal) is generated at a position where the synchronization mark 3 and the premark 4 are located, as in the first embodiment, but the synchronization mark 3 and the premark 4 are opposite to each other. Push-pull signals are also generated in opposite directions.
Therefore, if a threshold level is set on each of the + side and the − side of the push-pull signal, the synchronization mark signal and the pre-mark signal can be easily detected. In addition, if the amount of displacement of the synchronization mark 3 and the pre-mark 4 is set to 1/4 or less of the track pitch TP, even when the respective marks are formed side by side in the radial direction, signals from the respective marks can be detected. .

Next, an optical disk recording / reproducing method according to the present invention will be described. In the optical disk recording / reproducing method according to the present invention, when recording / reproducing information on / from the optical disk described above, the number of rotations of the optical disk is controlled by a synchronization mark signal obtained from a synchronization mark, and the premark signal obtained from the premark is used. A position on the optical disk is detected, and information is recorded at a position on the optical disk to be recorded based on the detected position. In the optical disk shown in the second embodiment, since the synchronization mark and the premark are formed by displacing in the opposite directions, signals from the respective marks can be easily detected. Further, since the synchronization mark signal and the pre-mark signal are read out by one beam spot using the push-pull method, the configuration of the recording / reproducing apparatus can be simplified.

FIG. 4 is a block diagram showing a main part of an optical disk recording / reproducing apparatus for extracting a synchronization mark signal and a premark signal from a push-pull signal (PP signal). First, only the tracking error signal is extracted from the push-pull signal (PP signal) through the low-pass filter (LPF) 11, input to the tracking drive circuit 12, and outputs the tracking drive signal 12 a. on the other hand,
The mark signal is obtained by first passing a push-pull signal (PP signal) through a high-pass filter (HPF) 13,
The synchronization mark signal and the pre-mark signal are extracted. This is input to the synchronization mark signal detection circuit 14 and the pre-mark detection circuit 16.

The synchronization mark signal detection circuit 14 takes out the synchronization mark signal, generates a synchronization signal by the synchronization signal generation circuit 15, and controls the rotation speed of the optical disc as a spindle motor control signal 15a (see FIG. 1). Not output). On the other hand, a premark signal is taken out by a premark signal detection circuit 16, an address signal 17a is read by an address reading circuit (position detection circuit) 17 for detecting a position on the optical disk, and the result is sent to a horizontal feed control circuit (not shown). Output.

Next, the results of a specific evaluation test of the optical disk according to the present invention will be described. The optical disk used in this evaluation test is an optical disk having a phase-change recording film that can be recorded with a laser beam having a wavelength of 650 nm. The substrate is made of polycarbonate, and grooves, synchronization marks and pre-marks are formed by injection molding.
The groove has a width of about 0.35 μm, a depth of about 40 nm, and a track pitch of 0.74 μm, and is formed as a continuous spiral from the inner circumference to the outer circumference. After sequentially laminating a phase change recording layer, a reflective layer, and a protective layer on this substrate,
A phase change optical disk was manufactured by laminating another polycarbonate resin substrate having a diameter of 120 mm and a thickness of 0.6 mm.

In order to investigate the influence of the premark length, an experimental optical disk having a different premark length was manufactured, and the address reading error rate and PI error (ie, uncorrectable data error of the reproduced signal) of the optical disk were measured. did. The data of the land pre-pits of the DVD-R was used as the pre-mark data. As an information recording / reproducing device, an optical disk evaluation device DDU-1000 manufactured by Pulstec Industrial Co., Ltd. was used. The wavelength of the recording / reproducing light is 6
35 nm, NA of the objective lens is 0.60. Also,
To measure the address reading error rate and PI error,
The company's Signal Analyzer was used. Table 1 shows the address reading error rate and P of the optical disc.
4 shows a measurement result of an I error.

[0040]

[Table 1]

Here, the symbol T in Table 1 is a unit of the recording mark length of the information recorded on the optical disk.
= 38 ns (≒ 0.13 μm). As shown in Table 1, the premark length is 2T (≒ 0.26 μm, T = 38n).
In the case of s), the output of the pre-mark signal was small, so that the address read error rate after recording was large, which was not practical. In addition, when the premark length is 14T, the signal due to the prepit is superimposed on the reproduction signal, and the PI error is large, which is not practical. When the premark length is 4T to 12T, an optical disk which has a small address read error rate before and after recording, has a small PI error, and is sufficiently practical.

Therefore, the length Lp of the premark is 2
It is desirable to be in a range longer than T and shorter than 14T (2T <Lp <14T). Further, the length Ls of the synchronization mark is set shorter than the length of the premark, but is longer than 2T as in the case of the length Lp of the premark.
It is desirable to be within a range shorter than 14T (2T <L
s <14T).

[0043]

According to the first aspect of the present invention, in the optical disc according to the first aspect, since the synchronization mark and the pre-mark are formed by displacing the groove toward one of the lands, a narrow track is formed. Since a sufficient amplitude of the push-pull signal can be obtained even at the pitch, the rotation speed of the disk can be accurately controlled, and the preformat information can be reliably reproduced.

(2) Action and Effect Corresponding to Claim 2 In the optical disc according to claim 2, since the synchronization mark is formed shorter than the pre-mark, the synchronization mark signal and the address mark signal can be easily identified. Can be detected.

(3) Action and Effect Corresponding to Claim 3 In the optical disc according to Claim 3, since the synchronization mark is formed by being displaced in the direction opposite to the pre-mark, the synchronization mark signal and the address mark signal are generated. Can be easily identified and detected.

(4) Action and Effect Corresponding to Claim 4 In the optical disc according to claim 4, the displacement amount of the premark and the synchronization mark is set to を of the track pitch interval.
As described below, even when these are formed side by side in the radial direction, a signal based on the mark can be reproduced.

(5) Action and Effect Corresponding to Claim 5 In the optical disc according to claim 5, since the length Ls of the synchronization mark is set to 2T <Ls <14T, the synchronization mark signal can be accurately detected. The number of rotations of the disk can be accurately controlled. Also, the recorded information can be accurately reproduced.

(6) Action and Effect Corresponding to Claim 6 In the optical disc according to claim 6, since a plurality of synchronization marks are formed in a sector, information can be recorded at a correct position on the optical disc.

(7) Action and Effect Corresponding to Claim 7 In the optical disc according to claim 7, since the length Lp of the premark is 2T <Lp <14T, the premark signal can be accurately detected. Also, the recorded information can be accurately reproduced.

(8) Action and Effect Corresponding to Claim 8 In the optical disc according to claim 8, since the preformat information is dispersedly arranged in a plurality of sectors, data is continuously recorded on the optical disc. it can.

(9) Action and Effect Corresponding to Claim 9 In the optical disc according to claim 9, at least a synchronization pattern, address data, and error correction code data are included as preformat information. Information can be recorded at the correct position on the optical disc. Even if there is an error in the address data, correct address data can be detected by the error correction code.

(10) Action and Effect Corresponding to Aspect 10 In the optical disk recording / reproducing method according to the aspect 10, the synchronization mark signal and the pre-mark signal are detected by one beam spot. By using this, the configuration of the recording / reproducing apparatus can be simplified.

(11) Operation and Effect Corresponding to Aspect 11 In the optical disk recording / reproducing apparatus according to claim 11, since the synchronization mark signal and the pre-mark signal are detected by one beam spot, the configuration of the optical disk recording / reproducing apparatus. Can be simplified.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram for describing a first embodiment of an optical disc according to the present invention.

FIG. 2 is a conceptual diagram for explaining a second embodiment of the optical disc according to the present invention.

FIG. 3 is a diagram showing an example of preformat information recorded on an optical disc according to the present invention.

FIG. 4 is a block diagram showing a main part of an optical disk recording / reproducing apparatus for extracting a synchronization mark signal and a premark signal from a push-pull signal (PP signal).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... groove, 2 ... land, 3 ... synchronization mark, 4 ... premark, 11 ... low-pass filter (LPF), 12 ... tracking drive circuit, 12a ... tracking drive signal,
13 high-pass filter (HPF), 14 synchronization mark signal detection circuit, 15 synchronization signal generation circuit, 15a spindle motor control signal, 16 pre-mark detection circuit, 1
7 ... Address reading circuit (position detecting circuit), 17a ... Address signal.

Claims (11)

[Claims] In a recordable optical disk having a spirally formed groove, a preformat information having address information for position search and one of the lands are used as information for controlling the rotation speed of the disk. An optical disc characterized by forming a premark and a synchronization mark displaced to the side. 2. The optical disc according to claim 1, wherein
An optical disc, wherein a synchronization mark length is shorter than a premark length. 3. In a recordable optical disk having a spirally formed groove, a premark in which the groove is displaced to one of the lands is formed as preformat information, and the information is used as information for controlling the rotation speed of the disk. An optical disk characterized in that a synchronization mark is formed by displacing in a direction opposite to a premark. 4. The optical disk according to claim 3, wherein
An optical disc characterized in that the displacement of the pre-mark and the synchronization mark is not more than 1/4 of the track pitch interval. 5. The optical disc according to claim 1, wherein the length Ls of the synchronization mark is 2T <Ls <, where T is a unit of the length of a recording mark recorded on the optical disc. An optical disc characterized by being 14T. 6. The optical disk according to claim 1, wherein a plurality of the synchronization marks are formed in a sector. 7. The optical disk according to claim 1, wherein the length Lp of the premark is 2T <Lp <14T, where T is a unit of the length of a recording mark recorded on the optical disk. An optical disk characterized by the following. 8. The optical disk according to claim 1, wherein said preformat information is recorded in an address sector, said address sector comprising a plurality of sectors. 9. The optical disk according to claim 1, wherein the preformat information includes at least a synchronization pattern, address data, and error correction code data. An optical disc characterized by the following. 10. The optical disk recording / reproducing method for recording / reproducing information on / from an optical disk according to any one of claims 1 to 9, wherein the rotation speed of the optical disk is controlled by a synchronization mark signal detected from the synchronization mark, and the pre-mark is controlled. An optical disk recording / reproducing method, wherein the synchronous mark signal and the premark signal are detected by one beam spot by a push-pull method when a position on the optical disk is detected by a premark signal detected from the optical disk. 11. An optical disk recording / reproducing apparatus for recording / reproducing information on / from an optical disk according to any one of claims 1 to 9, wherein a detecting means for detecting the synchronization mark, and a rotation speed of the optical disk from the detected synchronization mark Control means for controlling the pre-mark, detecting means for detecting the pre-mark, and detecting means for detecting the position on the optical disc from the detected pre-mark, the detection means for each of the synchronization mark and the pre-mark An optical disc recording / reproducing apparatus characterized by using a push-pull method for detecting with one beam spot.