JP2002100057A - Optical head device, disk driving device and track detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical head capable of surely giving a track servo to recoding media having different track intervals, or one recording medium having different track intervals, a disk driving device and a track error detecting method. SOLUTION: This optical head device 1 is constructed in such a manner that for a first disk D having the tracks of a first interval or a second disk D having the tracks of a second interval different from the first interval, when an recording medium is irradiated with an optical beam containing 0-order and ±1-order optical spots, the 0-order optical spot is converged on a specified track, and the optical beam of the ±1-order optical spot is radiated between tracks equal in distance from the track of the converged 0-order optical spot, and thus a D-PP signal can be surely provided and a track can be surely followed up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive capable of recording information on a disk-shaped recording medium such as an optical disk or a magnetic disk. The present invention relates to an optical head device, a disk drive device, and a track error detection method capable of reliably applying track servo to recording media having different track intervals.

[0002]

2. Description of the Related Art CD-ROM, MO disk or D
A disk drive for reproducing information from a disk-shaped storage medium (disk) represented by a VD-disk or the like and recording information on a recordable disk is connected to, for example, a personal computer (PC) to operate the PC. Is used to supply system programs and software, or to supply and hold large amounts of data, and is connected to, for example, a television or a monitor device, and is used to reproduce video software and game software. The storage capacity of these discs has been increasing year by year since the first music CD was put to practical use.

[0003] Above all, a recordable CD-R disc of the CD standard is inexpensive and easily available as a single disc, and is increasingly provided as a standard disc drive for a PC. As a result, demand has grown significantly today.

A guide groove or track for guiding a recording position when data is recorded is formed in advance on a CD-R disc or a DVD-disc.

[0005] This track is usually detected by ± 1st order light spots generated on the left and right of the 0th order light spot of the recording beam using a diffraction grating, and the 0th order light should be recorded. Used for track servo for irradiating tracks.

[0006]

In the case of, for example, a CD-R disc, the distance between tracks is 1.6 .mu.m, so that the. +-. Primary light spot described above has a position of approximately 0.8 .mu.m with respect to the zero-order light spot. Is irradiated.

However, today, as a new disk, despite the fact that it is a CD-R standard disk, the interval between tracks is other than 1.6 μm, or an area where the interval between tracks is different in one disk. Has been proposed.

In this case, for example, the interval between tracks is
As shown in FIG. 5, in the case of 1.6 μm and 1.1 μm, the track servo currently used, especially D-
According to the differential push-pull (PP) method, it is difficult to accurately detect a target track for reproducing data at both track intervals.

That is, in a disk drive using a track servo of the D-PP system, there are cases where a plurality of disks formed at different track intervals or tracks at different intervals exist in one disk. In a disk having tracks at intervals and a track area at specific intervals, there is a problem that a D-PP signal cannot be obtained and data cannot be reproduced.

An object of the present invention is to provide a recording medium or a recording area having a track at a first interval and a recording medium or a recording area having a track at a second interval different from the first interval. It is an object of the present invention to provide an optical head device, a disk drive device, and a track detection method capable of obtaining a differential-push-pull signal for accurately detecting a signal.

[0011]

SUMMARY OF THE INVENTION The present invention has been made on the basis of the above-mentioned problems, and has a light source for emitting a light beam and a diffraction grating for generating ± 1 order light spots on the light beam from the light source. And ± 1 generated by this diffraction grating.
An objective lens for converging at least three beam spots of a next-order light spot and at least three beam spots of a zero-order light spot that has passed through the diffraction grating as they are, respectively, at a predetermined position on a recording medium;
In the optical head device having:
Recording medium having tracks at intervals of
When irradiating the recording medium with a light beam composed of a zero-order light spot and a ± first-order light spot on each of the second recording media having tracks at a second interval different from the interval of the And an optical head device capable of irradiating ± 1st order light spots between tracks of a recording medium at equal distances from the track on which the 0th order light spot is converged. To provide.

Further, the present invention provides a semiconductor laser device for emitting a laser beam having a predetermined wavelength, a ± primary light spot generated from a laser beam from the light source, and a predetermined laser beam provided on a recording surface of a recording medium. A diffraction grating for passing the principal ray of the laser beam as it is toward the track as a zero-order light spot; condensing the zero-order light spot passing through the diffraction grating on a predetermined track on a recording medium; Are focused on the recording medium between the track separated by a predetermined distance from the track on which the zero-order light spot is converged on the recording medium and the next track. An objective lens, and a laser beam reflected from the recording medium by each of the zero-order light spot and the ± first-order light spot, A hologram plate directed in a direction at a predetermined angle with respect to an axis defined between the objective lens, and a hologram plate defined by the hologram plate with respect to an axis defined between the semiconductor laser element and the objective lens; A first photodetector that receives a reflected laser beam from the recording medium due to the zero-order light spot changed to an angle and outputs a corresponding electric signal; and the semiconductor laser element and the objective lens by the hologram plate. ± changed to a predetermined angle with respect to the axis defined between
A second receiving a reflected laser beam from the recording medium by each of the primary light spots and outputting a corresponding electric signal;
And the + photodetector generated by the first photodetector.
A difference signal between an electric signal corresponding to light reflected from the recording medium by the primary light spot and an electric signal corresponding to light reflected from the recording medium by the -1st light spot by the first photodetector; And a difference signal obtained by further adding an electric signal corresponding to the reflected light from the recording medium by the 0th-order light obtained by the photodetector and condensed on the recording medium through the objective lens. A tracking error signal for matching the center of the zero-order light spot with the center of the track of the recording medium is obtained, and the center of the zero-order light spot focused on the recording medium through the objective lens and the track of the recording medium are obtained. A tracking control circuit that matches the center of
The present invention provides a disk drive device characterized by having:

Further, according to the present invention, a first recording medium or a recording area having a track at a first interval and a track of a second recording medium or a recording area having a track at a second interval different from the first interval are used. In the method of detecting,
A predetermined track on a recording surface of the recording medium is irradiated with a zero-order light spot, and a first recording medium or a recording area having tracks at a first interval is shifted from a track irradiated with the zero-order light spot to a first track. Between tracks at a distance,
With respect to a second recording medium or a recording area having tracks at the second interval, which are irradiated with the ± first-order light spots, a first recording medium or a recording area defined with respect to the first recording medium or the recording area from the track irradiated with the zero-order light spot Irradiating a ± 1st order light spot between tracks located at positions substantially equal to the distance of 1;
A difference signal between an electric signal corresponding to the reflected light from the recording medium due to the +1 order light spot and an electric signal corresponding to the reflected light from the recording medium due to the −1 order light spot, and the reflected light from the recording medium due to the 0 order light The difference signal obtained by adding the difference signal of the electric signal corresponding to the difference between the center of the zero-order light spot focused on a predetermined track of the recording medium through the objective lens and the center of the track is obtained. An object of the present invention is to provide a track detection method characterized by obtaining a track error signal as a quantity.

Still further, the invention provides a light source for emitting a light beam, a diffraction grating for generating a ± 1st order light spot on the light beam from the light source, and a ± 1st order light spot generated by the diffraction grating. An objective lens that focuses at least three beam spots of the zero-order light spot that have passed through the diffraction grating as they are at a predetermined position on a recording medium, wherein the diffraction grating is a A first with a first spaced track defined
A light beam composed of a zero-order light spot and a ± first-order light spot is recorded on each of the recording mediums having different tracks from the first interval and having the tracks at the second interval defined by b. When irradiating the medium, when n is an integer defining a predetermined magnification, m is an integer defining a predetermined magnification, and when the 0th-order light spot is focused on a predetermined track, ± 1st-order light spot From the track where the zero-order light spot is focused, to a position determined by (na + a / 2) ≒ (mb + b / 2).

Still further, the present invention is directed to a first recording medium or recording area having tracks at a first interval and a second recording medium or recording area having tracks at a second interval different from the first interval. In the method for detecting the first position, a predetermined track on the recording surface of the recording medium is irradiated with a zero-order light spot, and n is set to a predetermined value with respect to the first recording medium or the recording area having the first interval track defined by a. When the magnification of 整数 is defined as an integer, the ± 1st order light spot is radiated to the position obtained by na + a / 2 from the track irradiated with the 0th order light spot, and the track at the second interval specified by b When m is an integer that defines a predetermined magnification for the second recording medium or recording area having
From the track irradiated with the zero-order light spot, mb + b /
Irradiate the position determined by 2 with the ± 1st order light spot,
A difference signal between an electric signal corresponding to the reflected light from the recording medium due to the primary light spot and an electric signal corresponding to the reflected light from the recording medium due to the −1st order light spot, and the reflected light from the recording medium due to the zero-order light The difference signal obtained by adding the difference signal of the electric signal corresponding to the difference between the center of the zero-order light spot focused on a predetermined track of the recording medium through the objective lens and the center of the track is obtained. The present invention provides a track detection method for obtaining a track error signal which is a quantity, wherein (na + a / 2) ≒ (mb + b / 2) holds.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. The embodiment described below is merely one of preferred examples, and the scope of the present invention is not limited to the embodiment.

FIG. 1 is a schematic diagram illustrating a state where an optical head device of an optical disk device to which an embodiment of the present invention can be applied is extracted. FIG. 1 illustrates an example in which data is recorded on a CD-R type optical disc on which data can be recorded.

The optical head device 10 shown in FIG.
For example, a laser beam (light beam) having a wavelength of 785 nm
Semiconductor laser element 1 as a light source for outputting light, and a zero-order light, which is a principal ray of a laser beam emitted from the semiconductor laser element 1, is transmitted as it is, and a diffraction grating (grating) that generates ± primary light spots from the principal ray. 2, diffraction grating 2
The three spot lights of the ± 1st order light spot and the 0th order light spot generated by the above are passed toward the recording surface of the optical disc D as the recording medium, and the reflected laser beam reflected by the recording surface of the optical disc D A hologram plate 3 for giving a predetermined imaging pattern by three regions 3A, 3B and 3C as shown in FIG. 1B, a collimating lens 4 for collimating (parallelizing) a laser beam passing through the hologram plate 3, The laser beam collimated (parallelized) by the collimating lens 4 is
The hologram plate 3 is condensed on the recording surface of the optical disk D and reflected by the recording surface of the optical disk D, passes through the objective lens 5 and the collimating lens 4 in order, and is
And a photodetector 6 that detects the laser beam whose optical path has been changed by the hologram plate 3 and outputs an electric signal corresponding to the light intensity, that is, a current or a voltage.

The laser beam emitted from the semiconductor laser device 1 is converted into three beams by generating ± primary light spots in addition to the chief ray of the zero-order light by the diffraction grating 2, and passes through the hologram plate 3. Then, the light enters the collimator lens 4.

The laser beam entering the collimator lens 4 and passing through the collimator lens 4 is converted into collimated light, which is parallel light, and guided to the objective lens 5.

The laser beam guided to the objective lens 5 is converged by the objective lens 5 into a beam spot having a predetermined size, and the zero-order light spot among the three spots irradiates a predetermined track on which data is to be recorded. Is done. The ± 1st-order light spots are respectively radiated between tracks between the track irradiated with the 0th-order light spot and a track located at a predetermined distance.

The laser beam reflected from the track of the optical disc D is returned to the objective lens 5 and
Gives convergence and is returned to the hologram plate 3. The optical path of the reflected laser beam returned to the hologram plate 3 is changed by the hologram plate 3 toward the photodetector 6.

FIGS. 2A and 2B are schematic diagrams illustrating the state of diffraction given to the laser beam emitted from the semiconductor laser element 2 by the diffraction grating of the optical head device shown in FIG. .

As shown in FIG. 2A, the diffraction grating 2
The laser beam that has passed through the optical disk D has a zero-order light spot corresponding to a track on which information is to be recorded, and both sides of the zero-order light spot. Are converted into three spots of the two ± primary light spots, and are irradiated onto a predetermined position of the disk D.

Needless to say, the zero-order light spot irradiates a track on which information is to be recorded, and the ± first-order light spots are:
Each is approximately 4 μm (1.
The disk D is irradiated at an interval of 6 × 2 + 0.8 / 2). That is, the diffraction grating 2 emits the chief ray of the incident laser beam as it is as a zero-order light spot, and at a predetermined interval (a distance of 4 μm in this example) from the zero-order light spot, ± 1 order light Generate spots. Note that FIG.
The track interval in the disk shown in FIG.
6 μm, showing an example of a well-known CD standard CD-R.

FIG. 2B shows a newly proposed disk in which the distance between tracks is 1.1 μm.

As shown in FIG. 2B, in the same manner as described with reference to FIG. 2A by the diffraction grating 2, a ± 1st-order light spot in which an interval of about 4 μm is given to the 0th-order light spot is considered. Since the track interval is 1.1 μm, there is no perfect agreement, but 1.1 × 3 + 1.1 / 2 = 3.8.
The non-track portion (land portion) between the tracks is located at a position approximately 5 μm and approximately 4 μm.
Compared to the disk having a track interval of 1.6 μm shown in FIG. 7A, two ± primary light spots are irradiated in a positional relationship that can be regarded as substantially the same.

As described above, in a plurality of optical disks having tracks with different intervals or an optical disk having tracks with different intervals in one disk, the zero-order light spot is focused on a predetermined track and By irradiating the light spot from the track where the 0th-order light spot is condensed to each other at a distance that can be regarded as being equal or substantially equal to each other, any distance between the disks having different track intervals can be obtained. In this case, a D-PP signal for differential push-pull (D-PP) can be obtained. The distance between the ± first-order light spots with respect to the zero-order light spot can be set to an arbitrary distance (interval) by rotating the diffraction grating 2 around the position where the zero-order light spot passes.

The zero-order light spot and the ± first-order light spots obtained in this manner always have one track on a plurality of tracks while the zero-order light spot is focused on the target track.
Since each laser beam passing through the objective lens 5 is passed through a portion different from the center of the objective lens 5 due to the lens shift, the offset of the track error signal It is useful to eliminate.

In FIG. 2A, the interval between the tracks is "a", and an arbitrary integer magnification indicated by "n" is considered. In FIG. 2B, the interval between the tracks is "b". When considering an arbitrary integer magnification indicated by “m”, (na + a / 2) ≒ (mb + b / 2) or (na + a / 2) = (mb + b / 2) holds for each track interval.

FIG. 3 is a schematic diagram illustrating the detection area of the photodetector 6 of the optical head device 10 described with reference to FIG. 1 when viewed from the plane.

As shown in FIG. 3, the photodetector 6 detects the reflected laser beam due to the zero-order light spot and the reflected laser beam due to the ± first-order light spot described with reference to FIGS. Photodiodes (cells) 6A to 6H. The photodiodes 6A and 6B are arranged at a predetermined distance from the remaining photodiodes 6C to 6H. Each of the photodiodes 6C to 6H is separated by a predetermined distance from a boundary line between the photodiodes 6A and 6B in order to detect a reflected laser beam by the ± 1st order light spot given a spread in a predetermined direction by the diffraction grating 2. It is located in.

As is clear from FIGS. 1 and 3, the zero-order light spot provided with the predetermined imaging characteristic by the first area 3A of the hologram plate 3 is
A and 6B are irradiated and used for focus control, respectively. The photodiodes 6G, 6C and 6E
In this example, the laser beam reflected by the + 1st-order light spot is applied to the center 6C by the imaging characteristics provided by the second area 3B of the hologram plate 3 in this example. Similarly, on the side of the photodiodes 6F, 6D and 6H, in this example, the reflected laser beam due to the -1st order light spot causes the central 6D due to the imaging characteristic given by the third region 3C of the hologram plate 3.
Is irradiated.

FIG. 4 is a schematic diagram for explaining an example of a signal processing circuit for processing output signals from the photodiodes 6A to 6H of the photodetector 6 shown in FIG.

Each output signal of the photodiodes 6A to 6H is converted from a current to a voltage by an amplifier (not shown) and amplified to a predetermined level.

Each of the amplified photodiodes 6
Of the outputs A to 6H, the output of 6E, which is a laser beam reflected by the + 1st-order light spot, and the output of 6G, which is a laser beam reflected by the -1st-order light spot, are supplied to the first adder 21.
The output of 6F, which is a laser beam reflected by the + 1st-order light spot, and the output of 6H, which is a laser beam reflected by the -1st-order light spot, are added by a second adder 22, and further added to each adder. The addition results of 21 and 22 are combined by the first differential amplifier 23.

In the amplified photodiodes 6A to 6H, the output of 6C, which is a laser beam reflected by the zero-order light spot, and the output of 6D are combined by the second differential amplifier 24. The output of the first differential amplifier 23 previously synthesized and the output of the third differential amplifier 25 are further synthesized, and the differential-push-pull (D-
As a PP) signal, it is input to a tracking control circuit 32 for matching the center of the track with the center of the zero-order light spot.

On the other hand, among the amplified photodiodes 6A to 6H, the output of the laser beam 6A reflected by the zero-order light spot and the output of the laser beam 6B are combined by the fourth differential amplifier 26. Focusing is performed as a focus error signal for matching the position of the objective lens 5 with a position at a predetermined depth of a track on the recording surface of the optical disc D and a distance at which the laser beam focused by the objective lens 5 is focused, that is, a focal length. It is input to the control circuit 31.

That is, in the state where the 0-order light spot (main beam) is radiated to the center of the target track, the two ± primary light spots (sub-beams) generated by the diffraction grating 2 By irradiating each track with a predetermined distance at a position separated by an arbitrary number of tracks + ／ track, a 180 ° position is generated between the push-pull signal of the main beam and the push-pull signal of the sub beam. It gives a phase difference. This DP
By using the P signal, even if the known track error signal used in the tracking control circuit 32 is offset by the influence of the displacement of the objective lens 5 due to the lens shift, it is not affected by the offset. Accurate tracking control of the lens 5 becomes possible.

In the optical head device having such a signal detection system, the CD-R disk D is
When set to 1, the drive motor 12 for rotating the turntable 11 is rotated at a predetermined speed, and a laser beam of a predetermined power is emitted from the semiconductor laser element 1 by the control of a laser drive circuit (not shown).
The recording surface is irradiated.

Hereinafter, under the control of the CPU 51, when it is detected that the information (data) to be recorded is supplied to the recording data memory 33 from the outside or a buffer memory (not shown), the control of the laser drive circuit 34 is performed. By
A laser beam having a predetermined (reproducing) power is output from the semiconductor laser element 1, and the optical head device 1 is moved in the radial direction of the optical disk D by a head moving mechanism (not shown), so that information is already recorded. The area is searched.

Next, on an arbitrary track of the optical disc D,
The optical head device 1 is moved and the tracking control circuit 32
The eccentricity (displacement in the radial direction during one rotation of the disk) of the optical disk D is checked based on the output from the optical disk D, and the objective lens 5 per one rotation of the optical disk D to be supplied from the tracking control circuit 32 to a track coil (not shown). The variation amount (track offset amount) is set, and the objective lens 5 is locked with respect to the eccentricity of the optical disc D.

Subsequently, the optical head device 1 is moved to a recordable area (track) of the optical disk D, and responds to the laser drive signal from the laser drive circuit 34 based on the data stored in the recording data memory 33. A laser beam having a predetermined power is irradiated onto a target track while being intensity-modulated by the recording data, thereby forming a pit row (recording mark).

It should be noted that even when the disk D has different tracks in a single disk with track intervals as shown in FIG. 5, the ± primary light spots generated by the diffraction grating 2 are generally Since the light is irradiated to the position of 4 μm, for example, in this example, the track pitch is 1.6.
μm and 1.1 μm, 1.6 × 2 + 1.6 / 2
= 4.00 μm, 1.1 × 3 + 1.1 / 2 = 3.85
With μm, it is possible to obtain a D-PP signal from which the offset component due to the influence of the displacement of the objective lens 5 due to the lens shift has been removed, regardless of the track at any interval.

Further, for example, when the disk D has tracks at intervals of the DVD-disk standard, the same disk drive device as the disk having the intervals of the CD type is used.
In order to obtain the D-PP signal, the track interval in the DVD-disk standard disc is 0.74 μm, so that 1.6 × 1 + 1.6 / 2 = 2.40 μm and 0.40 μm.
With 74 × 3 + 0.74 / 2 = 2.59 μm, the tracking control circuit 32 removes the D-PP signal from which the offset component due to the influence of the displacement of the objective lens 5 due to the lens shift is removed, regardless of the track at any interval. Is input to

As described above, even when there are a plurality of optical disks having different track intervals or tracks having different intervals in one disk, the zero-order light spot is focused on a predetermined track, and ± 1 Since the next light spot can be irradiated between the tracks of the recording medium which are respectively at the same distance from the track where the zero-order light spot is condensed, D
An optical head device that can obtain a -PP signal and can accurately track a track can be obtained.

As described above, the optical head device of the present invention
A light source that emits a light beam, a diffraction grating that generates ± primary light spots on the light beam from the light source, a ± primary light spot that is generated by the diffraction grating, and a light beam that passes through the diffraction grating as it is. An objective lens for focusing at least three beam spots of the next light spot at predetermined positions on a recording medium, wherein the diffraction grating has a first space having tracks at a first interval. When irradiating the recording medium or a second recording medium having tracks at a second interval different from the first interval with a light beam composed of a zero-order light spot and ± primary light spots, The 0-order light spot is focused on a predetermined track, and the ± 1st-order light spot is irradiated between the tracks of the recording medium at the same distance from the track on which the 0-order light spot is focused. Characterized in that it is a capability.

Also, the disk drive device of the present invention
A semiconductor laser element that emits a laser beam of a predetermined wavelength, and generates ± primary light spots from the laser beam from the light source, and directs the laser beam toward a predetermined track provided on a recording surface of a recording medium. A diffraction grating that passes the principal ray as it is as a zero-order light spot; a zero-order light spot that has passed through the diffraction grating is focused on a predetermined track on a recording medium; An objective lens for focusing the spot between a track separated by a predetermined distance from the track on which the zero-order light spot is converged on the recording medium and the next track, and an zero-order light. A laser beam reflected from the recording medium by the spot and the ± primary light spot is defined between the semiconductor laser element and the objective lens. A hologram plate directed to a direction of a predetermined angle with respect to the axis of the laser beam, and a 0-order light beam which is changed by the hologram plate to a predetermined angle with respect to an axis defined between the semiconductor laser element and the objective lens. A first photodetector that receives a reflected laser beam from a recording medium by a spot and outputs a corresponding electric signal, and an axis defined between the semiconductor laser element and the objective lens by the hologram plate. A second photodetector for receiving a reflected laser beam from the recording medium by each of the ± primary light spots changed to a predetermined angle and outputting a corresponding electric signal; and a first photodetector. An electric signal corresponding to the reflected light from the recording medium due to the generated + 1st order light spot and the recording medium according to the -1st order light spot by the first photodetector. And a difference signal between the electric signal corresponding to the reflected light from the recording medium and the electric signal corresponding to the reflected light from the recording medium due to the zero-order light obtained by the second photodetector. According to the difference signal, a tracking error signal for matching the center of the zero-order light spot focused on the recording medium through the objective lens with the center of the track of the recording medium is obtained, and recording is performed through the objective lens. A tracking control circuit for matching the center of the zero-order light spot focused on the medium with the center of the track of the recording medium.

Further, according to the track detecting method of the present invention, a first recording medium or a recording area having a track at a first interval and a second recording medium or a recording medium having a track at a second interval different from the first interval are provided. In the method of detecting a track in an area, a predetermined track on a recording surface of a recording medium is irradiated with a zero-order light spot, and the zero-order light spot is located on a first recording medium or a recording area having tracks at a first interval. A ± primary light spot is radiated between tracks at a first distance from the illuminated track, and a 0th-order light spot is formed on a second recording medium or a recording area having tracks at a second interval. The first defined from the irradiated track with respect to the first recording medium or recording area
± 1st order light spots are radiated between tracks located at positions substantially equal to the distance of, and an electric signal corresponding to the reflected light from the recording medium by the + 1st order light spot and the reflected light from the recording medium by the -1st order light spot The difference signal obtained by adding the difference signal from the electric signal corresponding to the optical signal and the difference signal of the electric signal corresponding to the reflected light from the recording medium due to the zero-order light passes through the objective lens through the objective lens. It is characterized in that a track error signal, which is the amount of deviation between the center of the zero-order light spot focused on the track and the center of the track, is obtained.

The optical head device according to the present invention further comprises a light source for emitting a light beam, and a light beam from the light source.
A diffraction grating for generating a ± first-order light spot, ± first-order light spots generated by the diffraction grating, and at least three beam spots of a zero-order light spot that has passed through the diffraction grating as they are are respectively transmitted to a recording medium. And an objective lens for condensing light at a predetermined position,
The diffraction grating is different from a first recording medium having a first interval of tracks defined by a or a first interval,
When irradiating each of the second recording media having tracks at the second interval defined by b with a light beam composed of a zero-order light spot and ± primary light spots, n is set to a predetermined magnification. When m is an integer that defines a predetermined magnification, when the 0th-order light spot is focused on a predetermined track, the ± 1st-order light spot is converted to a track on which the 0th-order light spot is focused. Therefore, it is possible to collect light at a position determined by (na + a / 2)） (mb + b / 2).

Further, according to the track detecting method of the present invention, the first recording medium or the recording area having the track of the first interval and the second recording medium or the recording medium having the track of the second interval different from the first interval are provided. In a method of detecting a track in a recording area, a predetermined track on a recording surface of a recording medium is irradiated with a zero-order light spot, and a first track defined by a
When n is an integer that defines a predetermined magnification for the first recording medium or recording area having tracks at the intervals of
The position determined by a / 2 is irradiated with a ± 1st order light spot, and a second track having a second interval of tracks defined by b
In the case where m is an integer that defines a predetermined magnification for the recording medium or recording area of, the position ± 1 from the track irradiated with the 0th-order light spot is obtained by ± 1
A secondary light spot is irradiated, a difference signal between an electric signal corresponding to the reflected light from the recording medium by the + 1st-order light spot and an electric signal corresponding to the reflected light from the recording medium by the −1st-order light spot, and the 0th-order light By the difference signal obtained by adding the difference signal of the electric signal corresponding to the reflected light from the recording medium by the
In a track detection method for obtaining a track error signal which is an amount of deviation between the center of a zero-order light spot focused on a predetermined track of a recording medium through an objective lens and the center of the track, (na + a / 2) (Mb + b / 2).

[0052]

As explained above, according to the present invention,
When there are a plurality of optical disks having different track intervals or tracks having different intervals in one disk, an D-PP signal can be reliably obtained, and an optical head device capable of accurately tracking tracks can be obtained. .

Thus, it is possible to obtain a disk drive capable of recording information on a plurality of types of disks having different track intervals or a disk including tracks having different intervals, and capable of accurately reproducing already recorded information.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of an optical head device to which an embodiment of the present invention is applied.

FIG. 2 is a schematic diagram illustrating a positional relationship of a spot of a laser beam applied to a track on a recording surface of an optical disk by the optical head device shown in FIG.

3 is incorporated in the optical head device shown in FIG.
FIG. 4 is a schematic diagram illustrating an example of a photodetector capable of detecting a laser beam reflected from a track of an optical disc by a +2 order light spot described with reference to FIG.

FIG. 4 is a schematic diagram showing an example of a signal processing circuit that can process a signal detected by the photodetector shown in FIG. 3 and generate a D-PP signal.

FIG. 5 is a schematic diagram illustrating an example of an optical disc having two types of tracks with different intervals.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Semiconductor laser element, 2 ... Diffraction grating (grating), 3 ... Hologram plate, 4 ... Collimate lens, 5 ... Objective lens, 6 ... Photodetector, 6A ... · Focus error photodiode, 6B ··· Focus error photodiode, 6C · · · 0th order light spot photodiode, 6D · · · 0th order light spot photodiode, 6E · + 1st order light spot Photodiode, 6F... + 1st order light spot photodiode, 6G... -1st order light spot photodiode, 6H... -1st order light spot photodiode, 10... Optical head device, 31 ... Focus control circuit, 32 ... Tracking control circuit, 33 ... Recording data memory, 34 ... R The drive circuit, 51 ··· CPU, D ··· optical disk (recording medium).

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D118 AA26 BA01 CA13 CA23 CD03 CF03 CF09 CF16 CG04 CG17 CG24 CG36 CG44 5D119 AA41 BA01 BB01 DA05 EA02 EC21 FA05 JA22 KA02 KA10 KA16 KA17

Claims (11)

[Claims] A light source for emitting a light beam; a diffraction grating for generating a ± 1st order light spot on the light beam from the light source; a ± 1st order light spot generated by the diffraction grating; And an objective lens for condensing at least three beam spots of the zero-order light spot that have passed through the optical disk at predetermined positions on the recording medium, respectively. A light beam composed of a zero-order light spot and a ± first-order light spot is applied to each of the first recording medium having the first or second recording mediums having tracks at a second interval different from the first interval. When irradiating, the zero-order light spot is focused on a predetermined track, and the ± first-order light spots are separated from the track on which the zero-order light spot is focused on tracks of the recording medium at the same distance from each other. An optical head apparatus which is a possible radiation therebetween. A first photodetector for receiving reflected light from each of the ± primary light spots from the recording medium and outputting an electric signal corresponding to the light intensity of the reflected light; A second photodetector that receives light reflected by each of the next light spots and outputs an electric signal corresponding to the light intensity of the reflected light; and +1 generated by the first light detector. A difference signal between an electric signal corresponding to the reflected light from the recording medium due to the next light spot and the electric signal corresponding to the reflected light from the recording medium due to the minus primary light spot by the first photodetector;
And a difference signal obtained by further adding an electric signal corresponding to the reflected light from the recording medium by the 0th-order light obtained by the photodetector and condensed on the recording medium through the objective lens. 2. The optical head device according to claim 1, wherein a track error signal for obtaining the center of the zero-order light spot and the center of the track of the recording medium is obtained. 3. The light reflected from each of the ± primary light spots from the recording medium is directed to the first photodetector, and the reflected light from the zeroth-order light spot from the recording medium is detected by the second light detector. 3. The optical head device according to claim 2, further comprising a hologram plate capable of being directed to the container. 4. A semiconductor laser device for emitting a laser beam of a predetermined wavelength, a ± primary light spot is generated from a laser beam from the light source, and a spot is formed on a predetermined track provided on a recording surface of a recording medium. A diffraction grating that passes the principal ray of the laser beam as it is to the zero-order light spot, and focuses the zero-order light spot that has passed through the diffraction grating on a predetermined track on the recording medium, and is generated by the diffraction grating. An objective lens for focusing the ± 1st order light spots between a track at a predetermined distance from a track on which a 0th order light spot is focused on the recording medium and a track between the track and the next track. And a laser beam reflected from the recording medium by each of the zero-order light spot and the ± first-order light spots, by using the semiconductor laser element and the objective lens. A hologram plate which is oriented at a predetermined angle with respect to an axis defined between the hologram plate and the hologram plate to change the angle to a predetermined angle with respect to an axis defined between the semiconductor laser element and the objective lens. A first photodetector that receives a reflected laser beam from the recording medium due to the generated zero-order light spot and outputs a corresponding electric signal; and a hologram plate that is defined between the semiconductor laser element and the objective lens. A second photodetector for receiving a reflected laser beam from the recording medium by each of the ± primary light spots changed to a predetermined angle with respect to the axis to be output and outputting a corresponding electric signal; An electrical signal corresponding to the light reflected from the recording medium by the + 1st-order light spot generated by the photodetector and the -1st-order light spot by the first photodetector. Wherein a difference signal between the electric signals corresponding to the reflected light from the recording medium by the second
And a difference signal obtained by further adding an electric signal corresponding to the reflected light from the recording medium by the 0th-order light obtained by the photodetector and condensed on the recording medium through the objective lens. A tracking error signal for matching the center of the zero-order light spot with the center of the track of the recording medium is obtained, and the center of the zero-order light spot focused on the recording medium through the objective lens and the track of the recording medium are obtained. And a tracking control circuit for matching the center of the disk drive. 5. The diffraction grating has one of a first recording medium having tracks at a first interval and a second recording medium having tracks at a second interval different from the first interval. In such a case, in a state where the zero-order light spot is focused on a predetermined track, the ± 1st-order light spot can be irradiated between tracks at equal distances from the track on which the zero-order light spot is focused. The disk drive device according to claim 4, wherein: 6. The diffraction grating has one of a first recording medium having tracks at a first interval and a second recording medium having tracks at a second interval different from the first interval. In this case, in a state where the zero-order light spot is converged on a predetermined track, the ± first-order light spot is divided into a first integer obtained by multiplying a half of the first interval by an arbitrary integer in the first recording medium. In the second recording medium, an arbitrary integer used in the first recording medium is set to a half of the second interval between the tracks between the number of tracks and the next track. 5. The disk drive device according to claim 4, wherein light can be collected between tracks between a second number of tracks multiplied by another different integer and a next track. 7. The diffraction grating according to claim 1, wherein when either the first recording medium or the second recording medium is set,
In the first recording medium, a first distance which is a distance between tracks between a first number of tracks obtained by multiplying a half of the first interval by an arbitrary integer and a next track is used. ,
In the second recording medium, one-half of the second interval
A second distance which is a distance between tracks between a second number of tracks multiplied by another integer different from an arbitrary integer used in the first recording medium and the next track, 7. The light-collecting device according to claim 6, wherein each of the light-collecting devices can collect light.
The disk drive device according to the above. 8. The disk drive according to claim 7, wherein said first distance and said second distance are defined to be substantially equal. 9. A method for detecting a track of a first recording medium or a recording area having a track of a first interval and a track of a second recording medium or a recording area having a track of a second interval different from the first interval. In the method, the predetermined track on the recording surface of the recording medium is irradiated with a zero-order light spot, and the first recording medium or the recording region having tracks at the first interval is shifted from the track irradiated with the zero-order light spot to the first track. A ± 1st order light spot is radiated between tracks located at a distance of 1 and a second recording medium or a recording area having a track at a second interval is firstly illuminated from a track irradiated with a 0th order light spot. Between tracks at positions substantially equal to the first distance defined for the recording medium or recording area
Irradiating the primary light spot, a difference signal between an electric signal corresponding to the reflected light from the recording medium by the + 1st light spot and an electric signal corresponding to the reflected light from the recording medium by the −1st light spot, The difference signal obtained by adding the difference signal of the electric signal corresponding to the reflected light from the recording medium due to the light, the difference between the center of the 0th-order light spot focused on a predetermined track of the recording medium through the objective lens and A track error signal which is an amount of deviation from the center of the track. 10. A light source for emitting a light beam, a diffraction grating for generating a ± 1st order light spot on the light beam from the light source, a ± 1st order light spot generated by the diffraction grating, and the diffraction grating And an objective lens for condensing at least three beam spots of the zero-order light spot, which have passed through as is, at a predetermined position on the recording medium, wherein the diffraction grating is defined by a Unlike a first recording medium having a track of one interval, or a first interval,
When irradiating each of the second recording media having tracks at the second interval defined by b with a light beam composed of a zero-order light spot and ± primary light spots, n is set to a predetermined magnification. When m is an integer that defines a predetermined magnification, when the 0th-order light spot is focused on a predetermined track, the ± 1st-order light spot is converted to a track on which the 0th-order light spot is focused. An optical head device capable of condensing light at a position determined by (na + a / 2)） (mb + b / 2). 11. A method for detecting a track on a first recording medium or recording area having a track at a first interval and a track on a second recording medium or recording area having a track at a second interval different from the first interval. Irradiating a predetermined track on a recording surface of a recording medium with a zero-order light spot, and defining a predetermined magnification with respect to a first recording medium or a recording area having a track at a first interval defined by a. When a zero-order light spot is irradiated, a ± 1st-order light spot is irradiated from the track irradiated with the 0th-order light spot to a position determined by na + a / 2, and a second track having a second interval defined by b When the m is an integer that defines a predetermined magnification for the recording medium or recording area of ± 1, the ± 1st order light spot is located at a position determined by mb + b / 2 from the track irradiated with the 0th order light spot. A difference signal between an electric signal corresponding to the light reflected from the recording medium by the + 1st-order light spot and an electric signal corresponding to the light reflected from the recording medium by the -1st-order light spot, and recording by the 0th-order light The difference signal obtained by adding the difference signal between the electric signals corresponding to the reflected light from the medium and the center of the zero-order light spot focused on a predetermined track of the recording medium through the objective lens, A track detection method for obtaining a track error signal which is an amount of deviation from the center, wherein (na + a / 2) ≒ (mb + b / 2) is satisfied.