JPH1186316A - Optical disk device, and optical disk recording/ reproducing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk device capable of surely detecting the position of an objective lens without increasing its cost and to provide a data recording reproducing method to be applied to the optical device. SOLUTION: An objective lens 30 is held by a lens holder 100 in which an opening part 102 having a center matched with the center of the lens is formed. One pair of photosensors S1, S2 arranged in parallel along a tracking direction are arranged in the vicinity of the opening part 102 in the holder 100. The diameter D1 of the opening part 102 is smaller than the beam diameter D2 of laser beams to be radiated toward the objective lens 30. The photosensors S1, S2 detect unwanted beams among the laser beams to be irradiated on the objective lens 30 and the position of the lens 30 is detected based on the difference between the detected values from the sensors S1, S2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device, and more particularly to an optical disk for recording data on both spiral land tracks and groove tracks formed on the optical disk and reproducing the data recorded on the optical disk. The present invention relates to a recording / reproducing apparatus and a recording / reproducing method applied to the optical disc recording / reproducing apparatus.

[0002]

2. Description of the Related Art In addition to an optical disc capable of recording data on only one of a land track and a groove track, an optical disc capable of recording data on both a land track and a groove track,
Alternatively, there are a reproduction-only type in which data other than data recorded at the time of manufacture cannot be additionally recorded, and a type in which data can be additionally recorded. These optical disks have an identification data area in the vicinity of the innermost circumference where identification data for identifying the type of the optical disk is recorded.

On the other hand, an optical disk recording / reproducing apparatus (hereinafter referred to as an optical disk apparatus) capable of recording data on such a plurality of types of optical disks and reproducing the recorded data has been put into practical use. I have.

This optical disk device has a spindle motor for rotating an optical disk at a predetermined rotation speed. The optical disk device also has an optical system for guiding a light beam generated by a light source to the optical disk, and an optical head equipped with an objective lens for focusing the light beam. The tracking control of the objective lens is performed based on the reflected beam from the optical disk so that the focused light beam follows the track of the optical disk during data reproduction or recording on the optical disk. That is, a tracking signal is generated based on the reflected beam from the optical disk, and the drive coil is driven based on the tracking signal, and the objective lens is moved in the tracking direction.

[0005] The optical head is movably supported by two guide shafts arranged parallel to each other along the radial direction of the optical disk. In addition, a linear motor is provided in parallel with the guide shaft to move the optical head along the guide shaft at the time of seeking to access a position over a plurality of tracks.

In such an optical head, when the center of the objective lens shifts with respect to the optical axis of the light beam from the light source during seek and tracking control,
There is a possibility that the tracking signal is offset and data is recorded in a state of being decentered with respect to the track.

For this reason, a position sensor for detecting the position of the objective lens by irradiating light to the lens holder holding the objective lens and detecting the reflected beam from the lens holder is provided on the optical head near the lens holder. Is provided.

[0008]

However, such a position sensor requires a light source, and the output of the sensor may be offset due to a decrease in the output of the light source, so that accurate position detection may not be performed.

Further, when mounting the sensor, precise adjustment of the mounting position of the sensor and adjustment of the sensor output are required, which causes a problem that the manufacturing process of the optical disk device becomes complicated. Thus, an external sensor that requires a light source
In addition to the problem of the reliability of the sensor itself and the adjustment accuracy of the sensor, the stable output of the light source is required, so that the sensor itself becomes expensive and the cost of the optical disk device itself increases.

Accordingly, an object of the present invention has been made in view of the above-mentioned circumstances, and an optical disk apparatus capable of reliably detecting the position of an objective lens without increasing the cost, and this optical disk. An object of the present invention is to provide a data recording / reproducing method applied to an apparatus.

[0011]

SUMMARY OF THE INVENTION The present invention has been made based on the above-mentioned problems, and according to the first aspect of the present invention, it has a diameter of a first size and is smaller than the first size. An opening for restricting the beam diameter of the light beam to the first size by passing a substantially parallel light beam having a large second size beam diameter, and a first size beam diameter passing through the opening An objective lens for focusing an approximately parallel light beam onto an optical disc having the opening, the opening being provided so as to be movable in a predetermined direction, and the center of the opening being coincident with the lens center of the objective lens. Supporting means for supporting the objective lens, and a detecting means for detecting a light beam regulated by the opening and detecting a deviation of the center of the objective lens from the optical axis of the light beam. When, the optical disk apparatus characterized by comprising a are provided.

According to the second aspect of the present invention, the light is transmitted by passing a substantially parallel light beam having a diameter of a first size and a beam diameter of a second size larger than the first size. An opening for regulating a beam diameter of the beam to the first size, an objective lens for focusing a substantially parallel light beam having a first size beam diameter passing through the opening onto an optical disc, and the opening, A support means is provided so as to be movable in a predetermined direction, and supports the objective lens so that the center of the opening and the lens center of the objective lens coincide with each other. A light beam provided near the opening, which is regulated by the opening, is detected, and a shift of the lens center of the objective lens with respect to an optical axis of the light beam along the predetermined direction is performed. Optical disc apparatus is provided which is characterized by comprising a knowledge detecting means.

According to the third aspect of the present invention, the substantially parallel light beam having a diameter of a first size and a beam diameter of a second size larger than the first size is allowed to pass, so that the light is transmitted. An opening for regulating a beam diameter of the beam to the first size, an objective lens for focusing a substantially parallel light beam having a first size beam diameter passing through the opening onto an optical disc, and the opening, A support means is provided so as to be movable in a predetermined direction, and supports the objective lens so that the center of the opening and the lens center of the objective lens coincide with each other. A light beam provided in the vicinity of the opening and controlled by the opening detects an amount of shift of the lens center of the objective lens from the optical axis of the light beam in the predetermined direction. Detecting means for detecting, and in order to make the optical axis of the light beam coincide with the lens center of the objective lens, move the supporting means with respect to the optical axis of the light beam based on the amount of displacement detected by the detecting means. An optical disk device comprising: a moving unit that moves in the predetermined direction.

According to the fourth aspect of the present invention, data is recorded by irradiating a focused optical beam to an optical disk having spiral land tracks and groove tracks formed by land portions and groove portions, and In an optical disk apparatus for reproducing data recorded on the optical disk, the optical disk device has a diameter of a first size and a substantially parallel light beam having a beam diameter of a second size larger than the first size. An opening for regulating a beam diameter of the beam to the first size, an objective lens for focusing a substantially parallel light beam having a first size beam diameter passing through the opening onto an optical disc, and the opening, Supporting means for supporting the objective lens such that the center of the opening coincides with the lens center of the objective lens; A first moving means for moving the support means in a predetermined direction so as to follow the light beam along a disk track, and a first moving means provided near the opening so as to be arranged in parallel along the predetermined direction; Detecting means for detecting a light beam regulated by an optical axis of the objective lens with respect to an optical axis of the optical beam and detecting a shift amount of the lens center of the objective lens along the predetermined direction; A second moving unit that moves the support unit in the predetermined direction with respect to the optical axis of the light beam based on the amount of displacement detected by the detection unit so as to match the lens center. An optical disk device is provided.

According to the fifth aspect of the present invention, the data recording surface of the optical disc having the spiral land tracks and the groove tracks formed by the land portions and the groove portions is irradiated with the focused light beam to irradiate the data. And an optical disk device for reproducing data recorded on the optical disk, allowing a substantially parallel light beam having a first size diameter and a second size beam diameter larger than the first size to pass therethrough. By doing
An opening for regulating the beam diameter of the light beam to the first size; an objective lens for focusing a substantially parallel light beam having the first size beam diameter passing through the opening onto an optical disc; Support means for supporting the objective lens such that the center of the opening coincides with the lens center of the objective lens; and a reflected beam from the optical disk for following a light beam along a track of the optical disk. Signal generating means for generating a tracking signal based on the first and second moving means for moving the supporting means in a predetermined direction based on the tracking signal; A light beam regulated by the opening, and detecting a predetermined position of a lens center of the objective lens with respect to an optical axis of the light beam. Detecting means for detecting an amount of displacement along the direction, and the support means is configured to control the light based on the amount of displacement detected by the detecting means so that the optical axis of the light beam coincides with the lens center of the objective lens. Second moving means for moving in the predetermined direction with respect to the optical axis of the beam, and a light beam corresponding to the recording data on a data recording surface of the optical disk by modulating the light beam based on recording data to be recorded. A data recording unit for generating a beam, and a data reproducing unit for generating a light beam for data reproduction and reproducing data recorded on the data recording surface based on a reflected beam from the data recording surface. An optical disk device characterized by comprising:

According to the sixth aspect of the present invention, a substantially parallel light beam having a beam diameter of a second size larger than the first size is passed through the opening having a diameter of the first size. The beam diameter of the light beam is set to the first
A substantially parallel light beam having a beam diameter of a first size that has passed through the opening is focused on the optical disk by an objective lens having a lens center that matches the center of the opening, and is regulated to an optical disk. Recording data or reproducing data, detecting a light beam regulated by the opening, and detecting a deviation of a lens center of the objective lens with respect to an optical axis of the light beam, recording on an optical disk. A playback method is provided.

According to the seventh aspect of the present invention, a substantially parallel light beam having a beam diameter of a second size larger than the first size is passed through the opening having a diameter of the first size. The beam diameter of the light beam is set to the first
A substantially parallel light beam having a beam diameter of a first size that has passed through the opening by an objective lens having a lens center coinciding with the center of the opening and having a lens center movably provided in a predetermined direction. Is focused on an optical disc to record or reproduce data on the optical disc, and is regulated by the opening by a pair of detecting means provided near the opening so as to be arranged in parallel along the predetermined direction. Detecting the displacement of the lens center of the objective lens with respect to the optical axis of the light beam based on the intensity of the light beam detected by the pair of detection means. An optical disk recording / reproducing method is provided.

According to the optical disk device of the present invention and the data recording / reproducing method applied to the optical disk device,
The diameter of the light beam having the second size larger than the first size is regulated to the first size by the opening having the first size diameter. In the vicinity of the opening, a light beam regulated by the opening, that is,
Detection means is provided for detecting the position of the objective lens by detecting a light beam that cannot pass through the opening.

This detecting means uses a light beam radiated toward the optical disk as a light source. Therefore, a new light source for detecting the position of the objective lens is not required, and it is possible to prevent an error in the tracking signal due to a change in the output of the light source. Further, since a light source is not required for the detecting means, it is possible to prevent the cost of the detecting means itself from increasing. Further, it is possible to prevent the cost of the optical disk device from increasing.

Further, since the opening is formed such that the center thereof coincides with the lens center of the objective lens, it is not necessary to adjust the optical axis of the detecting means. As described above, since it is not necessary to adjust the mounting position of the detecting means, it is possible to prevent the manufacturing process from being complicated.

Further, since the intensity distribution of the light beam passing through the opening is a Gaussian distribution, the light beam regulated by the opening, that is, the light beam at the outer peripheral portion of the light beam having a substantially circular cross section is used. The intensity changes sharply compared to the vicinity of the center. The detecting means can detect the displacement of the objective lens reliably and with good sensitivity by detecting the light beam whose intensity changes abruptly.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an optical disk device according to the present invention and a data recording / reproducing method applied to the optical disk device will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a configuration of an optical disk device according to an embodiment of the present invention. This optical disc device irradiates a converging light beam to the optical disc 1 to record data or reproduce data recorded on the optical disc 1.

The optical disc 1 is formed by coating a metal film layer such as tellurium or bismuth in a donut shape on the surface of a circular substrate made of, for example, glass or plastics. Also,
The optical disc 1 has a data recording surface composed of concentric or spiral grooves (concave portions) and lands (convex portions), and data is recorded on both the grooves and the lands, and is recorded on these. The data is played.

The optical disk 1 has a lead-in area 2, a data area 3, a lead-out area 4, and the like, as shown in FIGS. Lead-in area 2
Is an emboss data zone 5 consisting of a plurality of tracks
And a rewritable data zone 6 composed of a plurality of tracks. In the emboss data zone 5, reference signals and control data are recorded at the time of manufacturing. The rewritable data zone 6 includes a guard track zone, a disk test zone, a drive test zone, a disk identification data zone, and a replacement management zone as a replacement management area.

The data area 3 includes a plurality of, for example, 24 zones 3 formed by a plurality of tracks in the radial direction.
.. 3x. The lead-out area 4 is a rewritable data zone composed of a plurality of tracks and similar to the rewritable data zone 6 formed in the lead-in area 2. The lead-out zone 4 can record data having the same recording content as the data zone 6.

As shown in FIGS. 2 and 3, the optical disk 1 has a lead-in area 2 having an embossed data zone 5 and a rewritable data zone 6, and a data area 3 having zones 3a,. , And a data zone of the lead-out area 4 are formed.

As shown in FIG. 4, in the optical disk 1, the clock signal for each zone is the same, and the number of rotations of the optical disk 1 for each zone, that is, the rotation speed, the number of sectors for each track, and the like. Are different from each other.

That is, the zone 3a of the data area 3,
.. 3x, the rotation speed decreases as the optical disk 1 moves from the inner circumference to the outer circumference, and the number of sectors per track increases. Each of the zones 3a,... 3x,
The relationship between the rotation speed data and the number of sectors in one track for the data 4, 5, and 6 is shown in Table 1 of the memory 10 described later.
0a.

Zones 3a,... 3x of the data area 3
As shown in FIGS. 2 and 3, an ECC (error correction code) as a data recording unit
Data is recorded in advance for each block data unit (for example, 38688 bytes). As shown in FIG. 2, in the tracks of the zones 3a,... 3x of the data area 3, a header field 11 in which header data such as an address is recorded for each sector is pre-formatted in advance.

Here, the description returns to FIG. As shown in FIG. 1, the optical disc 1 is loaded on a spindle motor 23 while being held by a cartridge 21. The optical disk 1 is provided with a spindle motor 2
3, the rotation is performed at a different rotation speed for each zone. The spindle motor 23 is controlled by a motor control circuit 24.

The recording of data on the optical disk 1 or the reproduction of data recorded on the optical disk 1 is performed by the optical head 25. Spindle motor 23
The optical head 25 is provided on a fixed base as described later.

The optical head 25 is fixed to a drive coil 27 which constitutes a movable portion of a linear motor 26 as drive means, and the drive coil 27 is connected to a linear motor control circuit 28.

On the other hand, as shown in FIG. 1, a speed detector 29 is connected to a linear motor control circuit 28 for driving the linear motor 26, and the speed signal of the optical head 25 detected by the speed detector 29 is detected. Is the linear motor control circuit 2
8 to control the moving speed of the optical head 25.

The carriage 70 of the optical head 25 is provided with an objective lens 30, as shown in FIG. As will be described later, the objective lens 30 is held by a lens holder and movably supported by a wire or a leaf spring (not shown). The lens holder supporting the objective lens 30 is moved in the focusing direction (the optical axis direction of the lens) by the drive coil 31 and is moved in the tracking direction (the direction orthogonal to the optical axis of the lens) by the drive coil 32. Is done.

The semiconductor laser 39 is driven by a laser drive circuit 35 to generate a laser beam. The laser drive circuit 35 corrects the light amount of the laser beam generated by the semiconductor laser 39 according to the monitor current from the photodiode PD for monitoring the semiconductor laser 39.

The laser drive circuit 35 includes a PLL (not shown).
It operates in synchronization with a clock signal for data recording or data reproduction from a circuit. This PLL circuit divides the frequency of a basic clock signal from an oscillator (not shown) to generate a clock signal for data recording or data reproduction. In the laser drive circuit 35, the semiconductor laser 3
When a laser beam for data recording is generated from step 9, control is performed so as to generate a high-output laser beam higher than the laser beam for data reproduction by a predetermined level.

The laser beam generated by the semiconductor laser 39 driven by the laser drive circuit 35 is collimated by a collimator lens 40, and the optical path is bent at a substantially right angle by a half prism 41.
That is, the semiconductor laser 39 is formed by the half prism 41.
Is emitted toward the optical disc 1 in a collimated state. This laser beam is focused on the data recording surface of the optical disc 1 by the objective lens 30.

The light beam reflected from the data recording surface of the optical disc 1 passes through the objective lens 30 and the half prism 41, and is guided to the photodetector 44 via the condenser lens 42 and the cylindrical lens 43. I will

The photodetector 44 is composed of, for example, four divided photodetection cells 44a, 44b, 44c and 44d. The light detection cell 44 included in the light detector 44
The output signal a is supplied to one end of an adder 46a via an amplifier 45a, and the output signal of the photodetector cell 44b is supplied to one end of the adder 46b via an amplifier 45b. The output signal of the light detection cell 44c is supplied to the other end of the adder 46a via the amplifier 45c.
Is supplied to the other end of the adder 46b via the amplifier 45d.

The output signal of the photodetector cell 44a included in the photodetector 44 is supplied to one end of an adder 46c via an amplifier 45a, and the output signal of the photodetector cell 44b is supplied via an amplifier 45b. It is supplied to one end of the adder 46d. The output signal of the light detection cell 44c is
The output signal of the photodetector cell 44d is supplied to the other end of the adder 46d via the amplifier 45d via the amplifier 45d.
6c is supplied to the other end.

The output signal of the adder 46a is a differential amplifier O
The output signal of the adder 46b is supplied to a non-inverting input terminal of the differential amplifier OP2. Thus, the differential amplifier OP2 includes the adder 46a,
A signal relating to the focus point, that is, a focus error signal is supplied to the focusing control circuit 47 in accordance with the difference 46b. The output signal from the focusing control circuit 47 is supplied to the drive coil 31, and is controlled so that the laser beam is always just focused on the data recording surface of the optical disc 1.

The output signal of the adder 46c is a differential amplifier O
The output signal of the adder 46d is supplied to the non-inverting input terminal of the differential amplifier OP1. As a result, the differential amplifier OP1 includes the adder 46c,
A tracking error signal is supplied to the tracking control circuit 48 according to the difference of 46d. Tracking control circuit 48
Creates a track drive signal according to the tracking error signal supplied from the differential amplifier OP1.

The track drive signal output from the tracking control circuit 48 is supplied to the drive coil 32 in the tracking direction. The tracking error signal used in the tracking control circuit 48 is also supplied to the linear motor control circuit 28.

The sum signal of the outputs of the light detection cells 44a to 44d of the light detector 44 in the state where the focusing control and the tracking control are performed, that is, the adder 4
The signal obtained by adding the output signals from 6c and 46d by the adder 46e reflects a pit formed on the track, that is, a change in reflectance from the recording data. This signal is supplied to a data reproducing circuit 38, which reproduces data recorded on the data recording surface of the optical disk.

The reproduction data reproduced by the data reproduction circuit 38 is subjected to error correction by an error correction circuit 52 using an applied error correction code ECC, and then an optical disk as an external device is transmitted via an interface circuit 55. Output to control device 56.

A data generation circuit 34 is provided at a stage preceding the laser drive circuit 35. The data generation circuit 34 receives the format data of the ECC block as the recording data supplied from the error correction circuit 52,
Recording EC with synchronization code for ECC block
An ECC block data generation circuit 34a that converts the data into C block format data, and a modulation circuit 34b that modulates the recording data from the ECC block data generation circuit 34a using the 8-16 code conversion method.

The data generation circuit 34 is supplied with recording data to which an error correction code has been added by the error correction circuit 52 and dummy data for error checking read from the memory 10. To the error correction circuit 52, recording data from an optical disk control device 56 as an external device is supplied via an interface circuit 55 and a bus 49.

The error correction circuit 52 converts the 32 Kbytes of recording data supplied from the optical disk controller 56 into 4K bytes.
Each of the horizontal and vertical error correction codes (ECC1, ECC1) for the recording data in the sector unit for each byte.
2) and a sector ID (logical address number) to generate ECC block format data.

The optical disk device has a focusing control circuit 47 and a tracking control circuit 4 respectively.
8, and a D / A converter 51 used to exchange information between the linear motor control circuit 28 and the CPU 50 that controls the entire optical disk device.

Motor control circuit 24, linear motor control circuit 28, laser drive circuit 35, data reproduction circuit 38, focusing control circuit 47, tracking control circuit 4
8. The error correction circuit 53 and the like are connected to the CPU via the bus 49.
50. The CPU 50 has a memory 1
A predetermined operation is performed by the control program recorded in “0”.

The memory 10 stores a control program and is used for data recording. This memory 10
Has a table 10a in which the relationship between the speed data (the number of rotations) and the number of sectors in one track is recorded for each of the zones 3a, ..., 3x, 4, 5, and 6.

FIG. 5 is a perspective view showing the structure of the optical head 25 and the linear motor 26 shown in FIG. As shown in FIG. 5, the spindle motor 23, the optical head 25, the linear motor, and the like are provided in a housing formed of, for example, aluminum die-casting, that is, a fixed base 80.

The linear motor 26 is a plate-shaped center yoke 26 arranged in parallel along the radial direction of the optical disk.
a, a back yoke 26b provided to cover the center yoke 26a, and a permanent magnet 2 provided to the back yoke 26b so as to face the center yoke 26a.
6c and a drive coil 27 wound around a center yoke 26a and movably provided.

That is, the center yoke is inserted through the center of the drive coil 27. The drive coil 27 is connected to a linear motor control circuit 28, and the supplied current value is controlled. The drive coil 27 is excited by a current flowing from the linear motor control circuit 28 in a predetermined direction, so that the permanent magnet 26c
Propulsion is generated by interaction with a magnetic field formed so as to penetrate the center yoke 26a. The drive coil 27 uses the propulsive force to drive the center yoke 26a
, That is, in the radial direction of the optical disk.
The moving speed is determined by a current value supplied to the coil.

Center yoke 26a of linear motor 26
Are parallel to the guide shaft 71 as two cylindrical support means extending in the radial direction of the optical disc 1.
Are arranged in parallel.

The guide shaft 71 and the linear motor 2
The six center yokes 26b are fixed at predetermined positions on a fixed base 80 by fixing screws 91 in a state where they are arranged in parallel with each other. Then, with the back yoke 26c placed on the center yoke 26b, the center yoke 26b and the back yoke 26c are fixed to the fixing base 80 by fixing screws 92.

The carriage 70 functioning as the main body of the optical head 25 is fixed to the drive coil 27. The optical head 25 has two guide shafts 71.
And movably supported by the center yoke 26a via the drive coil 27. As described above, the optical head is moved in the radial direction of the optical disk by using the propulsive force generated by the interaction between the magnetic field formed by the drive coil 27 and the magnetic field penetrating the center of the drive coil 27. .

The carriage 70 has a guide shaft 71 for assisting movement on the guide shaft 71.
And a rotatably provided roller 72 that rotates with the movement of the carriage 70 while contacting the roller 72.

FIG. 6 is a sectional view schematically showing a lens holder holding an objective lens. As described above, the objective lens 30 provided on the optical head 25 is held by the lens holder 100. The lens holder 100 is movably supported by a wire or the like (not shown).

Then, as shown in FIG. 1, the lens holder 100 is driven in the focusing direction by the drive coil 31 while supporting the objective lens. Thereby, the light beam is always focused on the track of the optical disc 1 stably.

The lens holder 100 is driven in the tracking direction by the drive coil 32 while supporting the objective lens. As a result, the light beam always follows the desired track.

On the opposite side of the optical disc 1 with respect to the objective lens 30 in the lens holder 100, that is, on the half prism 41 side, a circular opening 102 having a diameter D1 is formed around the lens center of the objective lens 30. ing. That is, the center of the opening 102 is formed so as to coincide with the lens center of the objective lens 30. The diameter D1 of the opening 102 is set to be smaller than the beam diameter D2 of the collimated light beam, that is, the laser beam. Therefore, the opening 102
Functions as an aperture for regulating the laser beam having the beam diameter D2 to the beam diameter D1.

In a position near the opening 102 in the lens holder 100 and not blocking the opening 102, a pair of photo sensors S1 and S2 as detecting means are arranged in parallel along the tracking direction. Have been. Therefore, the photo sensors S1 and S2 detect the laser beam regulated by the opening 102. That is, a part of the laser beam which is not used as a reproduction or recording laser beam focused on the data recording surface of the optical disc is used as a light source, and a difference between detection values of a pair of photo sensors S1 and S2 is used. The shift amount of the objective lens in the tracking direction can be detected.

That is, as shown in FIG. 7, the output signals from the photosensors S 1 and S 2, that is, the voltage values whose levels change in accordance with the intensity of the detected laser beam are output to the comparator 104. Is done. The comparator 104 compares the levels of the output signals from the photosensors S1 and S2, and outputs a correction signal that changes in accordance with the shift amount of the objective lens 30 in the tracking direction to the tracking control circuit 48 according to the comparison result. I do. Further, the comparator 10
The correction signal output from 4 is also output to the CPU 50, and the CPU 50 can detect the position of the objective lens 30 based on the correction signal.

For example, as shown in FIG. 8, the optical axis of the laser beam indicated by the one-dot chain line in FIG.
When located at the center of the lens 0, that is, at the center of the opening 102, the laser beams having substantially the same level of intensity are incident on the photosensors S1 and S2. Therefore, the levels of the output signals output from the photo sensors S1 and S2 are substantially the same, and the comparator 104 indicates that the lens center of the objective lens 30 is substantially coincident with the optical axis of the laser beam. A correction signal is output.

Based on this correction signal, the CPU 50 detects that the lens center of the objective lens 30 coincides with the optical axis. In this case, the tracking control circuit 48 drives the drive coil 32 based on the tracking error signal output from the differential amplifier OP1 and, if necessary, drives the linear motor by the linear motor control circuit 28 to perform tracking control. Execute

Further, as shown in FIG. 9, the optical axis of the laser beam as indicated by the one-dot chain line in FIG.
Is shifted to the left in the drawing, that is, to the photosensor S1 side, the intensity of the laser beam incident on the photosensor S1 is higher than the intensity of the laser beam incident on the photosensor S2. Therefore, the level of the output signal output from the photosensor S1 is higher than the level of the output signal output from the photosensor S2, and
Outputs a correction signal indicating that the lens center of the objective lens 30 is shifted rightward in the figure from the optical axis of the laser beam. Since the correction signal changes according to the shift amount, for example, when the shift amount is large, a high-level correction signal is output.

Based on the level of the correction signal, the CPU
At 50, the objective lens 30 with respect to the optical axis of the laser beam
The shift amount at the center of the lens is detected. In this case, the tracking error signal output from the differential amplifier OP1 input to the tracking control circuit 48 includes the objective lens 3
An offset corresponding to a shift amount of 0 is superimposed. Therefore, in order to remove this offset from the tracking error signal, a correction signal that is output from the comparator 104 and that is dependent on the shift amount of the objective lens 30 is input to the tracking control circuit 48.

Then, in the tracking control circuit, after removing the offset from the tracking error signal based on the correction signal, the drive coil 32 is driven based on the tracking error signal, and the linear motor control circuit 28 controls the linear motor if necessary. To perform tracking control.

As described above, according to the optical disk device of the present invention and the data recording / reproducing method applied to the optical disk device, the opening of the diameter D1 allows the beam of the light beam having the beam diameter of D2 larger than D1. Diameter D1
Is regulated. A photosensor is provided near the opening to detect the position of the objective lens by detecting a light beam regulated by the opening, that is, a light beam that cannot pass through the opening.

This photosensor uses a light beam radiated toward an optical disk as a light source. Therefore, a new light source for detecting the position of the objective lens is not required, and it is possible to prevent an offset from being superimposed on the tracking signal due to a change in the output of the light source. Further, since a light source is not required for the photosensor, it is possible to prevent the cost of the photosensor itself from increasing. Further, it is possible to prevent the cost of the optical disk device from increasing.

Further, since the opening is formed so that its center coincides with the lens center of the objective lens, it is not necessary to adjust the optical axis of the photo sensor. That is, since it is not necessary to adjust the mounting position of the photosensor, it is possible to prevent the manufacturing process from being complicated.

Further, since the intensity distribution of the light beam passing through the opening is a Gaussian distribution, the light beam regulated by the opening, that is, the light beam at the outer peripheral portion of the light beam having a substantially circular cross section is used. The intensity changes sharply compared to the vicinity of the center. By detecting the light beam whose intensity changes sharply, the photo sensor can reliably detect the displacement of the position of the objective lens with good sensitivity.

[0074]

As described above in detail, according to the present invention, the optical disk device capable of reliably detecting the position of the objective lens without increasing the cost, and the data of the data applied to this optical disk device A recording / reproducing method can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a configuration of an optical disk device according to an embodiment of the present invention.

FIG. 2 is a plan view schematically showing a configuration of an optical disk applied to the optical disk device shown in FIG.

FIG. 3 is a block diagram schematically showing a configuration of a zone for each area of the optical disc shown in FIG. 2;

FIG. 4 is a diagram for explaining the number of rotations and the number of sectors per track in each zone of the optical disc shown in FIG. 2;

FIG. 5 is a perspective view schematically showing the structures of an optical head and a linear motor in the optical disk device shown in FIG. 1;

FIG. 6 is a sectional view schematically showing a structure of a lens holder of an objective lens provided in the optical head.

FIG. 7 is a block diagram showing a circuit configuration for detecting the position of an objective lens by the photo sensor shown in FIG. 6;

FIG. 8 is a diagram illustrating a state where the lens center of the objective lens and the optical axis of the laser beam coincide with each other.

FIG. 9 is a diagram illustrating a state where the lens center of the objective lens does not coincide with the optical axis of the laser beam.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 ... Lead-in area 3 ... Data area 23 ... Spindle motor 25 ... Optical head 26 ... Linear motor 28 ... Linear motor control circuit 30 ... Objective lens 32 ... Tracking drive coil 48 ... Tracking control circuit 50 ... CPU 100 ... Lens holder 102: Opening 104: Comparator

Claims (7)

[Claims] 1. A substantially parallel light beam having a diameter of a first size and a beam diameter of a second size larger than the first size is passed to reduce the beam diameter of the light beam to the first size. An opening for regulating a substantially parallel light beam having a beam diameter of a first size that has passed through the opening onto an optical disc; and an opening provided to be movable in a predetermined direction. Support means for supporting the objective lens such that the center of the opening coincides with the lens center of the objective lens; and the optical axis of the light beam by detecting a light beam regulated by the opening. An optical disk device comprising: a detection unit configured to detect a deviation of a center of the objective lens from the center of the objective lens. 2. Passing a substantially parallel light beam having a diameter of a first size and a beam diameter of a second size larger than said first size to reduce the beam diameter of said light beam to said first size An opening for regulating a substantially parallel light beam having a beam diameter of a first size that has passed through the opening onto an optical disc; and an opening provided to be movable in a predetermined direction. And supporting means for supporting the objective lens such that the center of the opening coincides with the lens center of the objective lens; provided near the opening so as to be arranged in parallel along the predetermined direction; Detecting means for detecting a light beam regulated by the opening and detecting a shift of the lens center of the objective lens with respect to an optical axis of the light beam along the predetermined direction. An optical disc device characterized by the above-mentioned. 3. Passing a substantially parallel light beam having a diameter of a first size and a beam diameter of a second size larger than the first size, the beam diameter of the light beam is reduced to the first size. An opening for regulating a substantially parallel light beam having a beam diameter of a first size that has passed through the opening onto an optical disc; and an opening provided to be movable in a predetermined direction. And supporting means for supporting the objective lens such that the center of the opening coincides with the lens center of the objective lens; provided near the opening so as to be arranged in parallel along the predetermined direction; Detecting means for detecting a light beam regulated by the opening and detecting a shift amount of the lens center of the objective lens with respect to an optical axis of the light beam along the predetermined direction; Moving means for moving the supporting means in the predetermined direction with respect to the optical axis of the light beam based on the amount of displacement detected by the detecting means so that the optical axis of the beam coincides with the lens center of the objective lens; An optical disk device, comprising: 4. An optical disk having a spiral land track and a groove track formed by a land portion and a groove portion is irradiated with a focused light beam to record data, and the data recorded on the optical disk is reproduced. An optical disk device having a diameter of a first size, and passing a substantially parallel light beam having a beam diameter of a second size larger than the first size, so as to reduce the beam diameter of the light beam to the first size. An opening for regulating a substantially parallel light beam having a beam diameter of a first size passing through the opening onto an optical disc; and an opening, wherein the center of the opening and the objective lens are provided. Supporting means for supporting the objective lens so that the lens center of the optical disc coincides with the center of the optical disc; First moving means for moving the support means in a predetermined direction to follow the beam, and a light beam provided near the opening so as to be arranged in parallel along the predetermined direction, and regulated by the opening. Detecting means for detecting and detecting a shift amount of the lens center of the objective lens with respect to the optical axis of the light beam along the predetermined direction; and for matching the optical axis of the light beam with the lens center of the objective lens. An optical disk device, comprising: a second moving unit that moves the support unit in the predetermined direction with respect to the optical axis of the light beam based on the amount of displacement detected by the detection unit. 5. A data recording surface by irradiating a focused light beam onto a data recording surface of an optical disk having a spiral land track and a groove track formed by a land portion and a groove portion, and recording the data on the optical disk. An optical disk device for reproducing the read data, wherein a substantially parallel light beam having a diameter of a first size and a beam diameter of a second size larger than the first size is passed, so that the beam diameter of the light beam is increased. An opening that regulates the light beam to the first size, an objective lens that focuses a substantially parallel light beam having a beam diameter of the first size that has passed through the opening onto the optical disc, Supporting means for supporting the objective lens such that the center and the lens center of the objective lens coincide with each other; Signal generating means for generating a tracking signal based on a reflected beam from the optical disk to follow a light beam along a rack; first moving means for moving the supporting means in a predetermined direction based on the tracking signal; A predetermined direction of a lens center of the objective lens with respect to an optical axis of the light beam, wherein the predetermined direction is provided near the opening so as to be arranged in parallel along the predetermined direction, and detects a light beam regulated by the opening; Detecting means for detecting a shift amount along the axis of the light beam; and adjusting the support means to the light beam based on the shift amount detected by the detecting means in order to match the optical axis of the light beam with the lens center of the objective lens. A second moving unit that moves in the predetermined direction with respect to the optical axis of the optical disc; modulates the light beam based on recording data to be recorded; A data recording means for generating a light beam corresponding to the recording data on a data recording surface of the disc, and a light beam for data reproduction, and the data recording surface based on a reflected beam from the data recording surface. An optical disc device, comprising: data reproducing means for reproducing data recorded in the optical disk. 6. A substantially parallel light beam having a beam diameter of a second size larger than the first size is passed through an opening having a diameter of a first size to reduce the beam diameter of the light beam. A substantially parallel light beam having a beam diameter of the first size and having passed through the opening is focused on the optical disk by an objective lens having a lens center coinciding with the center of the opening. Data recording or data reproduction, detecting a light beam regulated by the opening, and detecting a deviation of the lens center of the objective lens from an optical axis of the light beam, Recording and playback method. 7. A substantially parallel light beam having a beam diameter of a second size larger than the first size is passed through an opening having a diameter of a first size to reduce the beam diameter of the light beam. The objective lens is restricted to one size, has a lens center coinciding with the center of the opening, and is provided movably in a predetermined direction.
A substantially parallel light beam having a beam diameter of a first size that has passed through the opening is focused on an optical disc to record or reproduce data on the optical disc, and the data is reproduced in parallel along the predetermined direction. A pair of detecting means provided near the opening detects the intensity of the light beam regulated by the opening, and the light beam is detected based on the intensity of the light beam detected by the pair of detecting means. Detecting the deviation of the lens center of the objective lens with respect to the optical axis of the optical disk.