JP2000311345A - Optical recording and reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable management of address information and rotation control by a simple method by recording and reproducing information to an optical disk having grooves wobbled, managing an address information with pits and controlling rotation of the optical disk by wobbling. SOLUTION: An optical disk 1 executes recording and reproducing information at both wobbling grooves 1a... and lands 1b... sandwiched between the grooves, formatting for grooves 1a... an address signal for information management by modulating a wobbling frequency, and formatting for lands 1b... an address signal for information management by forming a pit 1c. In cases when a light spot formed by an optical head traces grooves 1a... or lands 1b..., as in either case peripheries of the grooves 1a... are irradiated by the light, the wobbling frequency can be detected all the time and, based on this, rotation control of a spindle motor can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing method for recording / reproducing information on / from an optical disk.

[0002]

2. Description of the Related Art Various demands have been made for recording and reproducing information having a resolution lower than the light resolution of a pickup of an optical recording / reproducing apparatus in response to a demand for higher density of an optical disk.

For example, Japanese Patent Application Laid-Open No. 5-81717 discloses that
A method for providing a magnetic layer on a perpendicular magnetization film and masking recorded information in an optical disc utilizing a magneto-optical effect to eliminate crosstalk of information from an adjacent track and to increase the density of information is disclosed. ing.

[0004] In the above method, it is possible to read information less than the resolution of the light spot, but the resolution of the tracking error signal for reading the information of the light spot is as follows.
It depends on the size of the light spot. For this reason, since a tracking error signal having a resolution equal to or less than the resolution of the light spot cannot be detected with high accuracy, the rotation of the optical disc cannot be accurately controlled, and the recording and reproduction of information cannot be performed accurately.

Japanese Patent Application Laid-Open No. 63-57859 discloses a method for increasing the density of information by recording and reproducing information on both lands and grooves of an optical disk. A soft format method has been proposed as a format method of an address signal for managing information on an optical disk in a method of recording and reproducing information on both the land and the groove.

However, in the above-mentioned soft format method, when an optical disk is used for the first time, an address signal is formed by an initial format in an optical recording / reproducing apparatus. Is required separately. For this reason,
The inside of the device becomes complicated, resulting in an increase in size and cost of the device.

Therefore, as another method of formatting address signals for information management, as shown in FIG. 6, for example, grooves 21a... And lands 21b. In both cases, a method of formatting an address signal by forming pits 21c at the time of molding an optical disc has been proposed. According to this method, an address signal is previously formatted (pre-formatted) at the time of molding an optical disc.
G), there is no need to perform initial formatting in the device, and there is no need to provide a member for initial formatting, and the configuration of the device can be simplified. Further, by recording and reproducing information on both the groove 21a and the land 21b of the optical disk 1, it is possible to increase the density of information.

As another preformatting method of address signals, for example, Japanese Patent Application Laid-Open No. 64-35727 discloses a method in which grooves are wobbled and the address signals are formatted at this time.
Also in this case, the address signal does not need to be soft-formatted, and the configuration of the device can be simplified.

[0009]

However, when an address signal is formatted by forming pits 21c on the grooves 21a and lands 21b of the optical disk 21, the optical disk 21 has the format shown in FIG. There are a portion where the pits 21c are not formed and a portion where the pits 21c are formed as shown in FIGS. 7 (b), 7 (c) and 7 (d). Therefore, the pits 21c formed in the grooves 21a and the lands 21b have different depths from the reference height, and it is necessary to form pits having two different depths. For this reason, the process for forming the pits 21c... Of the optical disk 21 is complicated, and the whole manufacturing process is complicated.

The optical disk 21 has a CLV (Co
When a track is formed by the ns tan nt Linear Velocity (constant linear velocity) method, since the track is formed in a spiral shape, the address signal formed by the preformat method is not on the same radius. If the track E is traced by a light spot, as shown in FIGS. 7A and 7B, when the pit 21c, that is, the address signal does not exist in both adjacent tracks, as shown in FIG. 7C. In the case where the address signal exists in both of the adjacent tracks, there may be a case where the address signal exists in only one of the adjacent tracks as shown in FIG.
Therefore, in each case, the intensity of the address signal due to the light spot changes, which makes address management difficult.

Further, as shown in FIG.
When the address signal exists only in one of the tracks adjacent to the track E, the pit exists asymmetrically with respect to the readout track. Therefore, an offset occurs in the tracking error signal, and the tracking servo control is not performed accurately. The signal quality is degraded.

In the method of managing an address signal in a groove by a wobbling method, an address signal of a groove is formed by a preformat method, but an address signal of a land cannot be preformatted. Formatting must be performed by a soft format method, and an apparatus for this is required, which causes a problem of increasing the manufacturing cost of the optical recording / reproducing apparatus.

[0013]

SUMMARY OF THE INVENTION The present invention has been made for the purpose of solving the above-mentioned problems, and is intended for an optical disk in which at least address information is formed by pits and wobbled with grooves as rotation control information for grooves and lands. An optical recording / reproducing method for recording / reproducing information by irradiating light having a spot diameter larger than a track width, wherein address information is managed by the pits, and rotation of the optical disc is controlled by the wobbling. An optical recording / reproducing method.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS.

As shown in FIGS. 1 and 2 (a), the optical disk 1 is composed of grooves 1a which meander (wobble) for improving the recording / reproducing density, and lands 1b which are sandwiched between the grooves 1a. Recording and reproduction of information are performed for both. Therefore, the above groove 1a
.. Format the address signal for information management by modulating the wobbling frequency at the time of molding the optical disc 1, and form the pits 1c at the lands 1b. Is formatted.

That is, the grooves 1a.
When a laser beam is irradiated, a wobbling signal having address information of the groove 1a uses a differential signal of an output of the light receiving unit 7, which will be described later.
When the laser beam is irradiated, the pit signal having the address information of the land 1b is used as the sum signal of the output of the light receiving section 7 to detect the address signal recorded on the groove 1a and the land 1b. Has become.

In the optical disc 1, when the light spot formed by the optical head 14 described later traces the groove 1a or the land 1b, the peripheral edge of the groove 1a Since the light is irradiated by the spot, the wobbling frequency can be always detected. Therefore, by detecting the tracking error signal based on the wobbling frequency, it is possible to control the rotation of the spindle motor 13 (FIG. 5) as the driving means for driving the optical disc 1 to rotate.

In the optical disk 1, the pits 1c are formed only on the lands 1b, so that the pits 1c are formed on both the groove 1a and the land 1b as in the prior art. There is no need for two types of pits, and only one type of pit 1c is required. Thus, the configuration for forming the pits 1c in the manufacturing process can be simplified, and as a result, the manufacturing cost of the optical disc 1 can be reduced.

Further, the depth of the pits 1c formed on the lands 1b of the optical disk 1 can be made to match the depth of the grooves 1a as shown in FIG. . Therefore, when the optical disc 1 is molded in this way, the manufacturing process can be further simplified, and the manufacturing cost of the optical disc 1 can be reduced.

In order to accurately detect an address signal preformatted on the optical disk 1, the optical disk 1
.. And pits 1c are λ / 10 to λ /
4, and the wobble amplitude of the groove 1a is desirably λ / 40 to λ / 7.

Further, at the time of molding the optical disk 1, address signals are formatted by wobbling in the grooves 1a, and pits 1c are formed in the lands 1b.
.., The address signal is formatted in both the groove 1a and the land 1b, so that it is not necessary to perform an initial format in an optical recording / reproducing apparatus or the like after molding an optical disc as in a soft format. This eliminates the need to provide a formatting mechanism in the apparatus in advance, and eliminates the need for a reference signal used for controlling the rotation of the spindle motor 13 (FIG. 5) of the optical disk during formatting.
As a result, the optical recording / reproducing apparatus for recording / reproducing information using the optical disc 1 having the above configuration has a simple configuration, and the apparatus can be reduced in size and cost.

In the groove 1a, an address signal is formed by wobbling, and in the land 1b, an address signal is formed by a pit 1c. Therefore, when tracing the land 1b, a pit is formed in an adjacent track, that is, in the groove 1a. 1c does not exist. by this,
Address signals recorded on the optical disc 1 are not affected by adjacent tracks. Therefore, no offset occurs in the tracking error signal, and an accurate tracking error signal can be obtained. Therefore, since the tracking servo can be performed accurately, information can be recorded and reproduced on the optical disk 1 accurately.

As shown in FIG. 3, a magneto-optical disk device as an example of an optical recording / reproducing apparatus for recording / reproducing information on / from the optical disk 1 having the above-described configuration has a An optical head 14 including a semiconductor laser 2 and a light receiving unit 7 as a light receiving unit that receives light reflected from the optical disk 1 is provided.

On the optical path from the semiconductor laser 2 to the optical disk 1 as a recording medium, a collimator lens 3, a polarizer 4, a light splitting element 5,
An objective lens 6 is arranged. That is, the semiconductor laser 2
The laser beam emitted from the laser beam enters the collimator lens 3 while being diffused, and is converted into parallel light. Further, the laser light passes through the light splitting element 5 and is condensed by the objective lens 6 to form a light spot A on the optical disc 1. The recording on the optical disk 1 is read by the reflected light from the light spot A.

The reflected light from the light spot A (hereinafter referred to as return light) is converted into parallel light by the objective lens 6 while diffusing again, and is incident on the light splitting element 5 and reflected. An analyzer 8 is arranged on the optical path of the return light reflected by the light branching element 5 so that it can enter the light receiving section 7.

The light receiving section 7 is composed of, for example, a phototransistor, and converts a signal recorded on the optical disc 1, a light modulation signal by wobbling for address management or a light modulation signal by pits into an electric signal. Has become. This makes it possible to manage the address information recorded on the grooves and lands of the optical disc by a simple method. As a result, the configuration of the optical recording / reproducing device can be simplified, and the size and cost of the device can be reduced.

The light receiving area of the light receiving section 7 is shown in FIG.
As shown in FIG. 1, the optical disk 1 is divided into two parts by a dividing line g parallel to the track, and a first light receiving element 7a and a second light receiving element 7b are provided in respective areas.
The second light receiving elements 7a and 7b can receive the incident light B from the optical disc 1 for each area. That is, the return light that is incident on the light receiving unit 7 is light that is divided into two by the above dividing line g, is incident on each of the light receiving elements 7a and 7b, and is converted into an electric signal. This electric signal is input to each amplifier described below, converted into an electric signal of a predetermined format, and input to a control device 12 as control means shown in FIG.

The first light receiving element 7a of the light receiving section 7 is connected in parallel to the non-inverting input terminal of the first differential amplifier 9, the non-inverting input terminal of the summing amplifier 10, and the non-inverting input terminal of the second differential amplifier 11. Are connected to the inverting input terminal of the first differential amplifier 9, the non-inverting input terminal of the summing amplifier 10,
It is connected in parallel to the inverting input terminal of the second differential amplifier 11.

Therefore, in the first differential amplifier 9, the first differential amplifier 9
A differential signal is calculated from the electric signal from the light receiving unit 7a and the electric signal from the second light receiving unit 7b, and this differential signal is output to the control device 12 as the rotation control signal Sa of the spindle motor. In addition, the summing amplifier 10 calculates a sum signal from the electric signal from the first light receiving unit 7a and the electric signal from the second light receiving unit 7b, and calculates the sum signal as the address signal S of the land 1b.
Output to the control device 12 as b. Further, the second differential amplifier 11 calculates a differential signal from the electric signal from the first light receiving unit 7a and the electric signal from the second light receiving unit 7b, and uses this differential signal as an address signal Sc of the groove 1a. Output to the control device 12.

Therefore, as shown in FIG. 5, the controller 12 controls the spindle motor rotation control signal Sa as shown in FIG.
Is input, the rotation of the spindle motor 13 is controlled, and when the address signals Sb and Sc are input, the optical head 14 is driven and controlled to move to a predetermined recording or reproducing position on the optical disk 1. Is controlled to record or reproduce information.

At this time, when the light spot traces the land 1b, the control device 12 sets the sum signal from the adder amplifier 10 as an address signal, and when the light spot traces the groove 1a, The differential signal from the second differential amplifier 11 is determined as an address signal, and the address information of the optical disc 1 is managed.

Although the optical head 14 shown in FIG. 3 shows an optical head for a magneto-optical disk utilizing the magneto-optical effect, the optical head according to the present invention is applicable to a recordable disk of another system. And the optical recording / reproducing device is applicable.

Further, in the recording / reproducing apparatus shown in FIGS. 3 to 5, although not shown in the drawings, a function of reproducing a signal recorded on an optical disk and generating and processing a servo signal is added to the apparatus. Needless to say,

According to the above configuration, when tracing the groove 1a of the optical disk 1, the first and second light receiving portions 7
The differential signal of the electric signal from the light receiving elements 7a and 7b is detected as an address signal.
Since the sum signal of the electric signals from the first and second light receiving portions 7a and 7b of the light receiving element 7 is detected as an address signal at the time of tracing, it is necessary to clearly detect the address signal between the groove 1a and the land 1b. Thus, crosstalk between address signals of adjacent tracks can be reduced. Therefore, it is possible to accurately record and reproduce information on the optical disk 1.

Further, the control device 12 controls the optical disk 1
When recording / reproducing information to / from the groove 1a, the address information recorded on the groove 1a is managed by a light modulation signal by wobbling, and the land 1b is recorded on the land 1b by a light modulation signal by a pit 1c. Since the managed address information is managed, the address information recorded on the groove 1a and the land 1b of the optical disc 1 can be detected by a simple method. Thus, the configuration of the device can be simplified, and the size and cost of the device can be reduced.

Also, since the spindle motor 13 is controlled based on the wobbling frequency information, when recording and reproducing information on both the groove 1a and the land 1b of the optical disk 1, the spindle motor 13 is accurately controlled. 13 can be controlled. by this,
Since the optical disc 1 can be rotated stably with a simple configuration, the size and cost of the apparatus can be reduced.

Further, when tracing the land 1b of the optical disk 1, the wobbling frequency of the adjacent groove can be detected. As a result, the wobbling frequency can be applied to the rotation control of the spindle motor 12, so that the CLV control of the optical disc 1 can be easily performed on both the groove 1a and the land 1c.

Here, the CLV format is adopted as the recording format of the optical disc 1, but the present invention is not limited to this, and other recording format formats may be used.
For example, CAV (Constant Angular V
(constant angular velocity) method may be employed. In this case, since the number of rotations of the spindle motor can be kept constant, the circuit of the apparatus can be simplified and the size of the spindle motor can be reduced.

Although the light receiving section 7 is divided into two parts in this embodiment, the present invention is not limited to this.

[0040]

According to the present invention, it is possible to manage the address information and control the rotation of the optical disk by a simple method.

Also, since the disk rotation can be accurately controlled for both the groove and the land, the optical disk can be easily and stably rotated.

[Brief description of the drawings]

FIG. 1 is a plan view of a track formed on an optical disc according to an embodiment of the present invention.

2A and 2B are cross-sectional views of a track of the optical disc shown in FIG. 1, wherein FIG. 2A is a cross-sectional view taken along line aa, and FIG. 2B is a cross-sectional view taken along line bb. FIG.

FIG. 3 is a schematic configuration diagram of an optical disk device that records and reproduces information on and from the optical disk shown in FIG.

4 is an explanatory diagram illustrating a light receiving element of the optical disk device shown in FIG. 3 and signal processing of the light receiving element.

5 is a control block diagram of the optical disk device shown in FIG.

FIG. 6 is a plan view of a track formed on a conventional optical disc.

7A and 7B show cross sections of tracks of the optical disc shown in FIG. 6, wherein FIG. 7A is a cross-sectional view taken along line aa, and FIG. 7B is a cross-sectional view taken along line bb. FIG. 3C is a cross-sectional view taken along line c-c, and FIG.
FIG. 4 is a cross-sectional view taken along line d.

[Explanation of symbols]

 Reference Signs List 1 optical disk 1a groove 1b land 1c pit 2 semiconductor laser (light source) 7 light receiving section (light receiving means) 7a first light receiving element (light receiving area) 7b second light receiving element (light receiving area) 12 control device (control means) 13 spindle motor ( Disc drive means) 14 Optical head

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Sekimoto 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Tomoyuki Miyaku 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Sharp Incorporated (72) Inventor Nobuo Ogata 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Inside (72) Inventor Toshiharu Inui 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Incorporated

Claims (1)

[Claims] An optical disk having at least address information formed of pits and wobbled with grooves as rotation control information of grooves and lands is irradiated with light having a spot diameter larger than a track width to record and reproduce information. An optical recording / reproducing method, wherein address information is managed by the pits, and rotation of the optical disk is controlled by the wobbling.