JPH10312576A - Disk apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk apparatus in which the recording and reproducing operation of a plurality of kinds of recording mediums especially having different recording densities or different recording-medium thicknesses can be performed by one optical head device. SOLUTION: A prescribed correction plate 9 is provided between an optical disk D and a light source 8. An aberration correction part 7 which corrects the aberration of light L, a diaphragm part 5 which changes the spot diameter, on the surface of an optical disk, of the light L, a through hole part 6 which does not block the light L and a shutter part 4 which blocks the light L are formed respectively in prescribed parts of the correction plate 9. Then, any of the aberration correction part 7, the diaphragm part 5, the through hole part 6 and the shutter part 4 is constituted so as to be freely positioned with reference to an optical path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive, and more particularly to a disk drive for reading and writing information from and on an optical disk.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of information processing devices and the increase in the amount of information handled by the information processing devices, the demand for increasing the recording capacity and miniaturization of information storage devices has been increasing. That is, increasing the recording density has become an important issue. The recording medium with the increased recording density may be a recording medium having the same structure as that of a conventionally used recording medium but with an improved recording density alone, or a storage medium having a specification different from that of a conventional recording medium. is there.

For example, a so-called DVD having a storage capacity approximately seven times that of a CD (compact disk) has a thickness of 0.6 mm of the recording medium itself. This is half of the CD media thickness of 1.2 mm. When a medium having a specification different from that of a conventional recording medium (such as a CD) is adopted as a high-density recording medium, such as a DVD, a disk device for recording and reproducing information uses a new recording medium that is different from the existing recording medium. It is desired that information can be recorded and reproduced on both of the high-density recording media.

However, in an optical head device which is actually widely used in a disk device, information is recorded and reproduced using a single objective lens. In this case, coma aberration occurs due to the difference in the thickness of the substrate, and information cannot be recorded / reproduced on both recording media with one objective lens.

In order to solve the above problems, some proposals have been made conventionally. JP-A-6-28
Japanese Patent Publication No. 2866 (first conventional example) provides an optical head corresponding to a plurality of types of disks by inserting a transparent substrate between the optical head unit and the optical disk. less than,
The above conventional example will be described with reference to FIG.

[0008] The disk device shown in FIG. 8 is designed to be compatible with a normal optical disk and a bonded disk 201 having a disk substrate half as thick. The transparent substrate 21 inserted into and removed from the optical path according to the substrate thickness of the disk between the objective lens 214 and the disk
5 are provided. In the case of a normal disk, the transparent substrate 215 is detached from the objective lens 214 to perform recording and reproduction. Further, in the case of supporting the bonded disk 201 having a disk substrate thickness of １ ／, the recording / reproducing is performed by inserting the transparent substrate 215 into an optical path to correct an aberration generated by the substrate thickness. I have.

Further, Japanese Patent Application Laid-Open No. 7-37259 (No. 2)
In the related art, a plurality of objective lenses are mounted on an optical head device, and recording and reproduction of a plurality of types of optical disks are enabled by selectively using one objective lens suitable for the mounted optical disk.

Hereinafter, the second conventional example will be described with reference to FIG. In the above-described disk device, the disk cartridge 101 can be arbitrarily used as a disk cartridge 101 of a standard specification or a non-standard disk cartridge having a higher recording density. The disk device is provided with a sensor 113 that can determine the type of the cartridge 101,
The type of the disc 107 can be determined.

In order to use an objective lens corresponding to the disc 107 that has been determined, a method of switching light to be incident on a plurality of types of mounted objective lenses (108 or 109) is adopted. The method uses the light emitted from the fixed optical system 102 and the mirror driving device 1.
Switching is performed by the mirror 105 driven by the reference numeral 06. The feature of this disk device is that, for different types of optical disks, the type of the optical disk itself is changed by changing the type of the disk cartridge 101, and the light is incident on the objective lens corresponding to the determined optical disk in the optical system. The point is that the optical path is switched to realize the recording and reproduction of the optical disk.

Japanese Patent Application Laid-Open No. 6-333255 (third conventional example) discloses an invention using a plurality of objective lenses.
Are disclosed. In this disk device, a plurality of different types of objective lenses are arranged side by side in the radial direction of the disk, and light is simultaneously incident on these objective lenses. The light incident on each objective lens is irradiated on the disk. The plurality of irradiated lights are reflected on the disk and returned to the photodetector to generate a plurality of error signals. From the error signal, the optimum objective lens is determined, and recording / reproducing of the optical disk is performed.

Further, as an invention of an optical head for recording / reproducing an optical disk having a plurality of types of recording densities, Japanese Patent Laid-Open No. 6-124 discloses an optical head.
There is one disclosed in Japanese Patent No. 477 (4th conventional example). According to the present invention, a liquid crystal filter is inserted into an imaging optical system, the diameter of light incident on an objective lens is changed according to the recording density of a recording medium, and the size of a light spot diameter on the recording medium is changed. And good reproduction characteristics. This may be achieved, for example, by a technique called apodization.

[0012] Further, there has been proposed an invention aiming at good reproduction of optical media having plural kinds of recording densities by one disk device. The present invention is roughly divided into two. One is to change the diameter of the parallel light incident on the objective lens to change the spot diameter on the disk. The other is to insert an electrolytic slit in the parallel optical path,
The super-resolution phenomenon is appropriately caused in accordance with the recording density of the disk to change the spot diameter.

[0013]

However, each of the above-mentioned prior arts has the following disadvantages. That is, in a disk device having an optical head equipped with one objective lens, the size of the light spot focused on the optical disk generally depends on the wavelength of the light of the LD as a light source and the numerical aperture (NA) of the objective lens. ). Therefore, when the spot diameter converged on the optical disk surface is determined by the wavelength of the LD light and the numerical aperture of the objective lens, which are optimally determined for a predetermined recording density, it is possible to perform recording / reproducing on an optical disk having other recording densities. Causes various problems.

First, when recording and reproducing an optical disk having a higher recording density than the original design, there is a disadvantage that a good reproduction signal cannot be obtained because the focused spot on the optical disk is larger than the recording density. Was occurring. Conversely, when trying to reproduce an optical disc with a lower recording density than the original design, if the designed numerical aperture is too large,
There is an inconvenience that the allowable range in which the warp of the optical disc can be reproduced becomes narrow, and the information cannot be appropriately reproduced.

When recording or reproducing an optical disk having a substrate thickness different from the original design, aberrations due to the substrate thickness are generated, and an appropriate spot diameter is not generated on the optical disk. On the other hand, there has been a problem that it is impossible to record and reproduce information. That is, in an optical head device equipped with one objective lens, a plurality of types of optical disks having different recording densities or recording medium thicknesses cannot be recorded and reproduced.

The recording pits recorded on the optical disk become smaller as the recording density becomes higher.
The size and density of dust adhering to the surface of the optical disk are irrelevant to the recording density of the optical disk. Therefore, the smaller the information pits recorded on the optical disk, the larger the size of the dust relative to the size of the information pits, which causes an error in information recording and reproduction. For this reason, an optical disc with a high recording density has a disadvantage that a recording / reproducing error due to adhesion of dust or the like is more likely to occur than an optical disc with a normal recording density.

In the case of an optical disc on which information is recorded in multiple layers, if the layer thickness of the multilayer optical disc is different from the originally designed substrate thickness of the objective lens to be mounted, aberrations are caused due to the difference in substrate thickness. Occur. For this reason, when trying to record / reproduce a multi-layer optical disc, if the layer thickness does not match the design of the objective lens, the spot diameter on the optical disc cannot be reduced to the limit value, and good recording / reproducing cannot be performed. It was causing inconvenience.

Furthermore, the objective lens is designed optimally for light of a certain wavelength, and if it is intended to use light other than the designed wavelength, the spot diameter on the optical disk cannot be reduced to the limit value. Was occurring.

[0019]

An object of the present invention is to solve the above-mentioned disadvantages of the prior art, and in particular, it is possible to perform recording and reproduction of a plurality of types of recording media having different recording densities or recording medium thicknesses with a single optical head device. To provide a simple optical disk device,
With that purpose.

[0020]

According to the first aspect of the present invention, there is provided an optical disk on which predetermined information is recorded, a light source for irradiating the optical disk with predetermined light, and a light source. In a disk device having an objective lens disposed between optical disks, a predetermined correction plate is provided between the optical disk and the objective lens, and light aberration is corrected at a predetermined position of the correction plate. An aberration correction section, a stop section for changing the spot diameter of light on the optical disk surface, a through-hole section for not blocking light, and a shutter section for completely blocking light are formed, respectively. A means is employed in which either the through hole or the shutter is configured to be freely positioned in the optical path of light.

With the above-described structure, when recording / reproducing a normal optical disk (CD, CD-ROM, etc.), if a light source for irradiating light having a shorter wavelength than that of a normal optical disk is used, the light can be recorded on the optical disk. The spot diameter of the collected light is smaller than the spot diameter collected by a normal CD-ROM device or the like. Therefore, if a stop portion for correcting the difference in the spot diameter is provided above the objective lens, the light passing through the objective lens is not only shielded by the outside light but also condensed on the optical disk. Then, the spot diameter on the optical disk becomes slightly larger than that when no light is emitted, and a condensed spot having a size suitable for the recording density can be obtained. This may be achieved, for example, by a technique called apodization.

On the other hand, the substrate thickness of an ordinary optical disk (1.
2 mm), when recording / reproducing an optical disc with an increased recording density, the spot diameter to be condensed on the optical disc must be small. However, as described above, by using light having a short wavelength from the beginning, the objective lens can be used. The passing light can be passed as it is, and the spot diameter can be reduced to the diffraction limit. As a result, recording / reproducing of an optical disk having a high recording density becomes possible. This is achieved by positioning the through hole of the correction plate above the objective lens.

When recording / reproducing an optical disk having a substrate thickness different from 1.2 mm, aberration occurs because the substrate thickness of the optical disk is different from the specification of the objective lens, and the spot diameter on the optical disk reaches the diffraction limit. If it is not stopped down, the optical disk having a different substrate thickness cannot be recorded and reproduced. Therefore, in order to correct the difference from the substrate thickness of 1.2 mm, a plate for correcting the difference in the thickness is attached to the aberration correction unit of the correction plate. Thus, when recording / reproducing an optical disc having a different substrate thickness, recording / reproduction can be performed by locating the aberration correction unit of the correction plate above the objective lens.

Furthermore, an optical disk with a high density has smaller information pits than an ordinary optical disk, and is likely to be susceptible to dust. In order to prevent dust from adhering to the lens, it is necessary to cover the objective lens. According to the present invention, in order to prevent dust from adhering to the objective lens, when recording / reproduction of the optical disc is not performed, the shutter portion of the correction plate is positioned above the objective lens to prevent dust from adhering to the objective lens. Can be prevented.

According to a second aspect of the present invention, at least two aberration correcting portions for realizing mutually different aberration corrections are formed at predetermined positions of the correction plate, and other configurations are described in the first aspect. Same as the invention. With the above configuration, even when reproducing a plurality of types of optical discs having different substrate thicknesses, recording and reproduction of the optical disc can be performed regardless of the difference in the substrate thickness by switching the respective aberration correction units. can do.

Further, the invention according to claim 3 employs a configuration in which at least two aperture portions for realizing mutually different spot diameters are formed at a predetermined location of the correction plate, and the other configuration is according to claim 1 or This is the same as the invention described in 2. With the configuration described above, even when reproducing a plurality of types of optical discs having different recording densities, recording and reproduction of the optical disc can be performed regardless of the recording density difference by switching the respective aperture portions. it can.

[0027]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the overall configuration of a disk drive 1 according to the present invention. Disk device 1
Includes an optical disk D on which predetermined information is recorded, a light source 8 for irradiating the optical disk D with predetermined light L, and an objective lens 3 disposed between the light source 8 and the optical disk D. A predetermined correction plate 9 is provided between the optical disk D and the light source 8, and an aberration correction unit 7 for correcting aberration of the light L is provided at a predetermined position of the correction plate 9, and a spot of the light L on the surface of the optical disk. A diaphragm section 5 for changing the diameter, a through-hole section 6 that does not block the light L, and a shutter section 4 that blocks the light L
Are respectively formed, and these aberration correction section 7, aperture section 5,
Either the through-hole portion 6 or the shutter portion 4 is configured to be freely positionable with respect to the optical path.

More specifically, the optical disc D can record and reproduce information by irradiating a predetermined light L to the surface. In the present invention, since the purpose is to record and reproduce optical disks of different types, the present invention is not limited to a specific type of optical disk. That is, the optical disk D may have a different substrate thickness or an optical disk having a different recording density per unit area. The optical disk D is carried by a spindle motor (not shown) and rotates at a predetermined rotation speed.

The fixed optical system 2 of the disk device 1 is provided with a predetermined light source (semiconductor LD) 8. This light source 8
Outputs a predetermined laser beam. A predetermined objective lens 3 is provided between the light source 8 and the optical disc D.
Are arranged. The objective lens 3 is for condensing the light L output from the light source 8 on the surface of the optical disc D.

The objective lens 3 is mounted on a lens actuator (not shown), and is configured to be movable in the radial direction of the optical disk D and to be able to approach and separate from the optical disk surface. The optical disk is configured to be able to approach and separate from the surface of the optical disk in order to focus the objective lens 3.
Further, the fixed optical system 2 is provided with a light receiving element (not shown) for receiving the reflected light from the optical disk D to obtain an error signal and a reproduction signal.

Next, the correcting plate 9 which is a feature of the present invention will be described. This correction plate 9 is carried by the fixed optical system 2. More specifically, the correction plate 9 is rotatably supported by a rotating shaft 10 protruding from the fixed optical system 2 to the optical disk D side. The shape of the correction plate 9 itself is circular, and the above-described rotary shaft 10 is engaged with the center of the correction plate 9. Therefore, the correction plate 9 is rotatable about the rotation axis 10.

At predetermined positions of the correction plate 9, a diaphragm 5, an aperture 6, an aberration correction unit 7, and a shutter 4 (the shutter 4 is a part of the correction plate 9) are respectively provided in the circumferential direction. It is formed along. Then, the correction plate 9 is disposed between the objective lens 3 and the optical disc D, and one of the aperture unit 5, the opening 6, the aberration correction unit 7, and the shutter unit 4 is inserted into and removed from the optical path of the light L of the light source 8. Can be switched. The actual switching of the correction plate 9 may be automatically selected and switched depending on the type of the installed optical disk, or may be manually selected.

Next, the function of each part of the correction plate 9 will be described.
First, the through-hole 6 has a sufficient opening area so as not to block the light L of the light source 8 at all. In the present invention, the size is not particularly limited as long as the through hole 6 is larger than the diameter of the light L at the position of the correction plate 9. That is, it may be a quadrangle, a triangle, or a polygon having five or more pentagons.

The diaphragm 5 is configured to block the light outside the light L passing through the objective lens 3. That is, unlike the above-described through hole 6, the through hole has a diameter slightly smaller than the diameter of the light L near the correction plate 9. In this manner, when the outer diameter of the light L is shielded by being formed smaller than the diameter of the light L, the spot diameter of the light L on the optical disk D can be slightly increased. Here, the spot diameter refers to the luminous intensity distribution of the light L on the optical disc D,
It refers to the diameter of the part exceeding the predetermined value. By passing the light L through the stop, the luminous intensity level in the central region of the light L is slightly reduced, while the region in the peripheral portion exceeding the predetermined luminous intensity level is enlarged, and as a result, the spot diameter becomes large. .

The aberration corrector 7 corrects the difference between the substrate thickness of the optical disk D, which the objective lens 3 is designed from the beginning of the design, and the substrate thickness of the optical disk D for actually recording and reproducing. The material of the aberration corrector 7 is desirably the same as the material of the disk substrate, but other engineering plastics or various kinds of glass can be used as long as the aberration can be corrected.

The shutter section 4 has a role of covering the objective lens 3 and is constituted by a part of the correction plate 9, and is not particularly processed as the shutter section 4. Therefore, in the present invention, all of the area other than the above-described through-hole section 6, aberration correction section 7, and aperture section 5 constitute the shutter section 4.

Next, a specific embodiment of the disk device 1 configured as described above will be described with reference to the drawings. FIGS. 2 to 6 show examples in which various types of optical disks are recorded / reproduced by using an optical disk having a substrate thickness of 1.2 mm as a basic specification and an objective lens 3 designed with a numerical aperture of 0.6. It is shown. The light source 8 has a wavelength of 635 nm (780 nm in a normal CD-ROM device).
m is used). When light having a short wavelength is used, the spot diameter of the light on the optical disk becomes smaller than usual, and it is possible to cope with an optical disk recorded at a high recording density.

FIG. 2 shows a normal substrate thickness (1.2 mm).
This shows an example in which the recording density is reproduced from the normal optical disc 20. The light emitted from the fixed optical system 2 passes through the objective lens 3 and passes through the diaphragm 5 on the correction plate 9.
And is focused on the optical disc 20. In this case, the light condensed on the optical disc 20 has a larger spot diameter condensed on the optical disc D than in the case where there is no diaphragm 5 as described above. As a result, recording / reproducing on / from the optical disk 20 recorded at a normal recording density becomes possible.

FIG. 3 shows an example in the case of recording / reproducing an optical disk 21 having an increased recording density with a normal substrate thickness (1.2 mm). Light emitted from the fixed optical system 2 is focused on the optical disk 21 by the objective lens 3. At this time, the through hole 6 of the correction plate 9 is arranged above the objective lens 3. Further, the light focused on the optical disk 21 by the objective lens 3 is not blocked at all by the through hole 6. By passing the light as it is, it is possible to record and reproduce information on the optical disk 21 having a small spot diameter and a high recording density, as described above.

FIG. 4 shows an example of recording and reproducing an optical disk (optical disk readable from both sides) 22 of a type in which two disk substrates each having a thickness of 0.6 mm are laminated. Light emitted from the fixed optical system 2 is collected on the optical disk 22 by the objective lens 3. In this case, the aberration corrector 7 for correcting the difference in substrate thickness is positioned in the optical path of the light to be collected. This makes it possible to correct the aberration due to the difference in the substrate thickness, and converge the spot on the optical disc 22 to the diffraction limit determined by the wavelength of the light source 8 and the numerical aperture of the objective lens 3. As a result, recording and reproduction can be reliably performed even on the bonded optical disk 22.

FIG. 5 shows an example in the case where the multilayer optical disk 23 is reproduced. In this case, it is necessary to change the type of the aberration corrector 71 to be corrected depending on the layer to be reproduced. Therefore, the aberration correction unit 71 capable of responding to each layer
Is mounted on the correction plate 9. In this embodiment, since information is recorded over four layers, at least three types of aberration correctors 71 are required. However, the aberration correction unit 7
One type is not limited to three types, but may be one or two types, or four or more types.

FIG. 6 shows an example in which the optical disk is not recorded and reproduced. In order to prevent dust or the like from adhering to the objective lens 3 when recording and reproduction are not performed, a correction plate 9 is provided.
(A part that can cover the objective lens) 4 is positioned above the objective lens 3. Shutter section 4
Is a part of the correction plate 9 that has not been processed at all.
An area other than the above-described through-hole 6 and the aperture 5 serves as the shutter 4.

As described above, in the embodiment shown in FIGS. 2 to 6, a predetermined specification is given for the numerical aperture of the objective lens 3, but the specification of the objective lens is arbitrarily set according to the type of the optical disk for recording and reproducing. be able to.

FIGS. 7A, 7B, 7C, and 7D each show an example of the configuration of a correction plate according to the present invention. Here, FIG. 7A shows an example in which one aperture unit 5, one aberration correction plate 7, and one opening 60 are provided in the correction plate 9a. That is, each part is arranged side by side in the circumferential direction. The other part is the shutter unit 50.

FIG. 7B shows that the diaphragm 5 and the correction plate 9b
In this example, one aberration correction plate 7 and one shutter portion 50 are provided, and the through-hole portion is supplemented by a portion without the correction plate 9b. That is, the through-hole portion need only be designed so as not to block light, and does not need to be specially formed in a circular shape. Therefore, the T-shaped correction plate 9b functions similarly as shown in the drawing.

FIG. 7C shows the diaphragm 5, the three aberration correctors 7a, 7b, 7c, the through-hole 6, and the shutter 50.
This is an example of the correction plate 9c configured as follows. By forming a plurality of aberration correctors 7a, 7b, 7c in this way, it is possible to perform recording / reproducing of different types of optical disks corresponding to the types of the aberration correctors.

FIG. 7D shows an embodiment in which the diaphragm portions 5a and 5b, the aberration correction portions 7a and 7c, the through-hole portion 6, and the shutter portion 50 are provided on the correction plate 9d. Thus, a plurality of aberration correction units 7a and 7c and a plurality of aperture units 5a and 5b may be set according to the specifications of the optical disk to be recorded and reproduced.
That is, when recording / reproducing on / from optical discs having different recording densities, provision of a plurality of apertures makes it possible to cope with optical discs having different recording densities.

The diaphragm can be configured not only mechanically but also with a diaphragm whose diameter can be varied, a diaphragm which can be electrically varied by a liquid crystal filter or the like, and a diaphragm which can be mechanically varied. It is.

[0049]

The present invention is constructed and functions as described above,
In particular, according to the first aspect of the present invention, a predetermined correction plate is provided between the optical disk and the objective lens, and an aberration correction unit for correcting light aberration is provided at a predetermined position of the correction plate; A stop portion for changing the spot diameter, a through-hole portion that does not block light, and a shutter portion that blocks light are formed, respectively, and any one of the aberration correction portion, the stop portion, the through-hole portion, or the shutter portion is placed in the optical path. Positioning.

For this reason, by properly switching one correction plate, the aberration caused by the substrate thickness can be corrected, and thereby, it is possible to record / reproduce an optical disk having a different substrate thickness or a multilayer optical disk. , Which is an excellent effect. Further, since the diameter of the light spot on the optical disk can be changed by the aperture portion, a light spot suitable for the recording density can be obtained, and a good reproduction signal can be obtained for optical disks of various recording densities. ,
This produces an excellent effect.

Further, since the correction plate is provided with a shutter portion capable of covering the objective lens, dust and the like can be effectively prevented from adhering to the objective lens. This produces an excellent effect that a good reproduction signal can always be obtained.

According to the second aspect of the present invention, at least two aberration correctors for realizing mutually different aberration corrections are formed at predetermined positions of the correction plate. For this reason, there is an excellent effect that recording and reproduction can be performed on an optical disk having a greater variety of substrate thicknesses.

Further, according to the third aspect of the present invention, at least two aperture portions for realizing mutually different spot diameters are formed at predetermined locations of the correction plate. For this reason, there is an excellent effect that recording / reproducing can be performed on an optical disk having more types of recording densities.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a side view showing a state in which an optical disk having a normal substrate thickness and a normal recording density is reproduced by the disk device disclosed in FIG. 1;

FIG. 3 is a side view showing a state in which an optical disk having a normal substrate thickness and a high recording density is reproduced by the disk device disclosed in FIG. 1;

FIG. 4 is a side view showing a state in which an optical disk having a half substrate thickness is reproduced by the disk device disclosed in FIG. 1;

FIG. 5 is a side view showing a state in which an optical disk recorded in multiple layers is reproduced by the disk device disclosed in FIG. 1;

FIG. 6 is a side view showing a state where an optical disk is not inserted into the disk device disclosed in FIG. 1;

FIG. 7A is a plan view showing an example of a correction plate according to the present invention, and FIG. 7A shows a correction plate provided with a through hole, a diaphragm, an aberration corrector, and a shutter, respectively. (B)
FIG. 7 (C) shows an arrangement provided with a plurality of aberration correction units, and FIG. 7 (D) shows an arrangement provided with a plurality of aberration correction units. Show what is provided.

FIG. 8 is a side view showing a conventional example.

FIG. 9 is a side view showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc apparatus 2 Fixed optical system 3 Objective lens 4 Shutter part 5 Aperture part 6 Through-hole part 7 Aberration correction part 8 Light source 9 Correction plate D Optical disk L Light

Claims (3)

[Claims] 1. A disk device comprising: an optical disk on which predetermined information is recorded, a light source for irradiating the optical disk with predetermined light, and an objective lens disposed between the light source and the optical disk. A predetermined correction plate is provided between the optical disk and the objective lens, and an aberration correction unit that corrects the aberration of the light at a predetermined position of the correction plate, and a diaphragm that changes a spot diameter of the light on the surface of the optical disk. Part, a through-hole part that does not block the light, and a shutter part that completely blocks the light, and any one of the aberration correction part, the stop part, the through-hole part, or the shutter part is provided in the optical path of the light. A disk device characterized in that it can be positioned freely. 2. The disk device according to claim 1, wherein at least two aberration correction units for realizing mutually different aberration corrections are formed at predetermined positions of the correction plate. 3. The disk device according to claim 1, wherein at least two aperture portions for realizing mutually different spot diameters are formed at predetermined locations of the correction plate.