JPH08297850A - Information recording and reproducing device - Google Patents

Abstract

PURPOSE: To attain the correction of the spherical aberration caused by the difference in thickness of a protecting layer without changing the driving sensitivity and the center of gravity of a movable part. CONSTITUTION: An aberration correcting mechanism 30 is provided with cover glasses 32 for correcting the spherical aberration and a link mechanism for movably supporting the cover glasses. The cover glasses 32 are parallel flat plates having the same refractive index as that of a cover glass of a disk 80, and the length thereof is slightly longer than the moving range of an objective lens 5. A link mechanism is provided with the links 33, 34, such as each one end is rotatably mounted on the end part of the cover glasses 32 and another ends are rotatably mounted on mounting parts 1a, 1b on a deck base 1. Further, the link mechanism is provided with a link 35 and a solenoid 36. One end of the link 35 is rotatably mounted at the center of the link 34, and another end is rotatably mounted on the solenoid 36. The solenoid 36 is fixed to a fixing part 1c on the deck base 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus for recording and / or reproducing information on an optical recording medium such as a CD, a magneto-optical disk or a phase change disk. In this specification, the term “recording / reproducing” means at least recording or reproducing.

[0002]

2. Description of the Related Art An information recording / reproducing apparatus for recording / reproducing information on / from a plurality of types of optical recording media has been proposed.
Examples of the plurality of types of optical recording media include a single-sided disc having only one information recording surface and a double-sided disc having two information recording surfaces. From the viewpoint of the characteristics of the spindle motor that rotates the disk, it is preferable that the disks have the same weight regardless of the type. The simplest way to satisfy this is to change the thickness of the protective layer (cover glass) covering the information recording surface of the single-sided disc and the double-sided disc. In this case, the thickness of the protective layer of the single-sided disc is It is about twice the thickness of the protective layer of the double-sided disc. In addition, the thickness of the protective layer is reduced so as not to increase the thickness of the double-sided disc, and the thickness of the protective layer is reduced so as to reduce the amount of coma aberration due to the tilt error between the disc and the disc. For reasons, multiple discs with different protective layer thicknesses are required.

The information recording / reproducing apparatus has various parameters in design, and is designed by setting one ideal value for each parameter. Therefore, there is one ideal value for the thickness of the protective layer. Therefore, spherical aberration becomes negligibly small for an optical recording medium having a protective layer thickness close to an ideal value, but spherical aberration becomes small for an optical recording medium having a protective layer thickness far from an ideal value. Becomes so large that it cannot be ignored. Therefore, one information recording / reproducing device is used as it is, like the above-mentioned single-sided disc and double-sided disc,
It cannot be applied to another type of optical recording medium in which the thickness of the protective layer is greatly different.

When recording / reproducing information on / from a plurality of types of optical recording media having different protective layer thicknesses in one information recording / reproducing apparatus, spherical aberration caused by the difference in protective layer thickness is It is necessary to take some measures to correct it.

In the apparatus disclosed in Japanese Patent Application Laid-Open No. 3-260934, a correction optical element is attached to a movable part having an objective lens according to the type of disc to be used, and the correction optical element is provided between the objective lens and the disc. By arranging the elements,
Corrects spherical aberration.

[0006]

This device has the following drawbacks. When a correction optical element is attached to the movable part,
Since the movable part becomes heavy, the driving sensitivity is reduced. In this way, the driving sensitivity varies depending on whether or not the correction optical element is attached to the movable portion, so that the servo gain of the driving head changes. Such a situation is not preferable from the viewpoint of control.

Further, the position of the center of gravity of the movable part changes depending on whether or not the correction optical element is mounted, so that the relationship between the position of the center of gravity of the movable part and the position where the driving force is applied changes, and the movable part moves. Revolving resonance occurs and the servo characteristics deteriorate.

Further, when the correction optical element is mounted on the movable portion, the movable portion is moved to the outside of the disk and the correction optical element is mounted at that position. Therefore, the movable portion is mounted for mounting the correction optical element. It is necessary to set a large moving range of, and the device is accordingly large.

The present invention is provided with means for correcting spherical aberration caused by the difference in the thickness of the protective layer without changing the drive sensitivity and the position of the center of gravity of the movable part and without increasing the size of the entire apparatus. An object is to provide a recording / reproducing device.

[0010]

DISCLOSURE OF THE INVENTION The present invention is an information recording / reproducing apparatus for recording / reproducing information on / from a plurality of types of optical recording media having different thicknesses of a protective layer covering an information recording surface, which is a fixed deck. A base, a light source that emits light for recording and reproducing information, an objective lens that focuses the light emitted from the light source on the information recording surface of the optical recording medium, and a movable unit that is movably provided with respect to the deck base. Then, with the movable part including the objective lens,
In the information recording / reproducing apparatus including the correction optical element that corrects the spherical aberration due to the difference in the thickness of the protective layer and the insertion means that appropriately inserts the correction optical element in the optical path from the light source to the optical recording medium, the insertion means is It has a support mechanism for movably supporting the correction optical element, and the support mechanism is fixed to the deck base.

[0011]

The correcting optical element for correcting the spherical aberration is movably supported by the supporting mechanism fixed to the deck base, and is appropriately provided in the optical path from the light source to the optical recording medium according to the type of the optical recording medium. Is inserted. That is, the correction optical element is moved by the support mechanism to a position that crosses the optical path when correction is necessary, and is moved to a position that is out of the optical path when correction is unnecessary.

With respect to the inserting operation of the correction optical element, the movable part is not affected at all, and the weight and the center of gravity do not change. Also,
There is no need to provide a space for the movable part to be located outside the optical recording medium.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. First Embodiment First, the first embodiment of the present invention will be described with reference to FIG.
-It demonstrates, referring FIG. The present embodiment is an example in which the present invention is applied to an information recording / reproducing apparatus using a magneto-optical disk as a recording medium.

As shown in FIG. 1 (a perspective view of the entire apparatus),
A spindle motor 60 that rotates a disk 80 is fixed to the deck base 1. The disk 80 is shown in FIG.
As shown in FIG. 5, the cartridge is located in the cartridge 4 having the opening 4a in the center. Returning to FIG. 1 again, the objective lens 5
The movable part 6 having a is supported so as to be movable in the X direction with respect to the deck base 1.

A fixed optical system 2 is provided on the + X side of the deck base 1.
8 is fixed. The fixed optical system 28 has a laser, a beam splitter, a photo detector, and the like. An aberration correction mechanism 30 is arranged on the deck base 1. The aberration correction mechanism 30 has a cover glass 32 that corrects spherical aberration due to a difference in the thickness of the protective layer (cover glass) of the disc 80, and the position of the cover glass 32 can be changed according to the type of the disc 80 mounted. By switching, spherical aberration is corrected.

As shown in FIG. 3 (perspective view of the movable portion) and FIG. 4 (exploded perspective view of the movable portion), the movable portion 6 has a structure in which an access coil 7 wound in a quadrangular prism shape is arranged in the center. The access coil 7 mainly bears the rigidity of the entire movable part. The carriage 8 attached to the access coil 7 is formed of, for example, a spherical epoxy resin containing silica, and has a fixing portion 8a that is bonded to the side surface of the access coil 7 on the −Y side. The surface on the -Y side of the access coil 7 is reinforced.

Bearings 9 and 10 on the reference side are formed at both ends in the X direction of the fixed portion 8a. The bearings 9 and 10 have bearings 9a and 10a, respectively, and both ends thereof are the deck base 1. Guide rail 11 fixed on top (see FIG. 1)
Is inserted. A fixing portion 8b for the mirror is formed between the two bearing portions 9 and 10, and the mirror 12 is fixed thereto by adhesion. The mirror 12 is a fixed optical system 2
The light emitted from 8 is reflected and made incident on the lens 5.

A driven-side bearing portion 13 is located on the + Y side of the access coil 7, and a guide rail 14 (see FIG. 1) is inserted into the U-shaped bearing 13a. Guide rail 1
Numerals 1 and 14 are made of ceramics of silicon carbide or stainless steel coated with fluorine. Bearing part 13
Is fixed to the + Y side surface of the access coil 7 by adhesion. The fixed portion 8a and the bearing portion 13 are connected by a connecting portion 8c, and are integrally formed as the carriage 8. The rigidity between the bearings 9 and 10 and the bearing 13 is mainly borne by the access coil 7. The carriage 8 may be formed by insert molding the access coil 7.

A connecting portion 8d projects from the bearing portion 10 toward the + Z side, and a fixing portion 8f is formed at the tip thereof. A part of the spherical surface having the nodal point of the objective lens 5 as the center is formed on the + X side of the fixed portion 8f, and the corresponding spherical surface formed on the −X side of the holding member 14 abuts on this spherical surface. After adjusting the tilt around the two axes of the objective lens 5 perpendicular to the Z axis, they are fixed by adhesion.

The spring 15 provided between the holding member 14 and the holder 16 is formed by pressing a stainless thin plate into a substantially U-shape. Holding member 14 and holder 16
Each is insert molded with plastic.

The lens 5 is fixed to the center of the holder 16, and the focus coil 17 wound in a square shape is fixed to both sides of the holder 16 in the Y direction. As shown in FIG. 2 (cross-sectional view showing the magnetic circuit), a center yoke 19 having a short ring 18 fixed to the periphery thereof is arranged in the space inside the access coil 7. In addition, the magnet 20 is formed so as to form a magnetic gap with the center yoke 19.
And the magnet 20 is fixed to the inside (−Z side) of the substantially U-shaped side yoke 21.
Both ends of the abutting contact with both ends of the center yoke 19 to form a magnetic circuit for access.

A magnet 22 is fixed to the side surface of the side yoke 21 on the -Y side so as to face the lower side 17a of the focus coil 17 on the + Y side. Further, the magnet 24 is fixed to the yoke 24 fixed to the deck base 1.
Is fixed to the yoke 24 so as to face the lower side 17a of the focus coil 17 on the −Y side.

Next, the operation of this embodiment will be described.
As shown in FIG. 2, magnetic fields in opposite directions in the Y direction act on the upper and lower two sides of the focus coil 17.
When a current is supplied to 7, a force in the Z direction is generated on these two sides, and the lens 5 can be driven in the Z direction. At this time,
The lens 15 is driven in the Z direction by bending the spring 15 supporting the holder 16 in the Z direction (see FIG. 3).

A magnetic field from the magnet 20 acts on the access coil 7, and when a current is passed through the access coil 7, a force in the X direction is generated in the access coil 7 to drive the movable portion 6 in the X direction. At this time, as shown in FIG. 1, the movable portion 6 has the bearings 9a, 10a, 13a and the guide rails 11, 1, respectively.
4 slides in the X direction.

As shown in FIG. 2, since the side yoke 21 is located in the opening 4a of the disc cartridge 4, the side yoke 21 can be brought closer to the optical disc 80 by that amount, and the height of the electromagnetic drive device can be increased. Can be made smaller.

As shown in FIG. 4, the carriage 8 is composed of the bearing portions 9, 10, 13 and the fixed portion 8b for fixing the mirror 12, the fixed portion 8a, and the connecting portions 8c, 8d, 8e. It has a simple structure without any. Further, since the access coil 7 mainly bears the rigidity between the bearing portions 9 and 10 and the bearing portion 13, the connecting portion 8c only needs to have a dimension such that resin flows when the bearing portion 13 is molded. The mass of may be minute.

When the movable portion 6 is driven in the X direction, the movable portion 6
Although warpage deformation of the entire X direction and Z direction, torsional deformation around the Y axis, and the like cause resonance, the access coil 7 is responsible for the rigidity of the entire movable portion 6, and there is no problem because the rigidity is high. Further, since the access coil 7 is made of a metal such as copper or aluminum, it has a higher elastic modulus and a higher resonance frequency than plastic.

In the coil movable electromagnetic drive device, the coil is always required for the movable part, but since this coil is the main structure and is responsible for the overall rigidity, it is another main structure. Carriage should be minimal.

Next, the aberration correction mechanism 30, which is a main part of the present invention, will be described with reference to FIGS. 1, 2 and 5. The aberration correction mechanism 30 has a cover glass 32 that corrects spherical aberration and a support mechanism (link mechanism) that movably supports the cover glass 32. The cover glass 32 is a parallel plate having a thickness t3 and the same refractive index as the cover glass (protective layer) 82 of the disk 80, and the length in the X direction is set to be slightly longer than the moving range of the objective lens 5 in the X direction. is there. The cover glass 32 is supported in parallel with the cover glass 82. The link mechanism movably supports the cover glass 32 in parallel with the disk 80.

The link mechanism has links 33 and 34, one end of which is rotatably attached to the end of the cover glass 32. The other ends of the links 33 and 34 are connected to the deck base 1
It is rotatably attached to the upper attachment portions 1a and 1b by a pin 37.

The link mechanism further includes another link 35,
It has a solenoid 36 for moving it. The link 35 has one end rotatably attached to the center of the link 34 by a pin and the other end rotatably fixed to the tip of the moving portion of the solenoid 36 by a pin. Solenoid 3
6 is fixed to a fixed portion 1c on the deck base 1.

When the moving part of the solenoid 36 extends in the direction of arrow A, the cover glass 32 moves to the + Y side and is inserted between the objective lens 5 and the disk 80 as shown by the solid lines in FIGS. To be done. In this case, since the cover glass 32 is located between the objective lens 5 and the disc 80,
The light emitted from the objective lens 5 passes through the cover glass 32 and then enters the disc 80.

On the contrary, when the moving part of the solenoid 36 retracts in the direction of the arrow A ', the cover glass 32 moves to the -Y side, and the objective lens 5 and the objective lens 5 are drawn as shown by the imaginary lines in FIGS. It is disengaged from between the disks 80. In this case, since the cover glass 32 is not located between the objective lens 5 and the disc 80, the light emitted from the objective lens 5 directly enters the disc 80.

The structure of two types of disks 80A and 80B having different cover glass thicknesses and the operation of the apparatus for each disk will be described with reference to FIG. In the following description, the disc 80A or the disc 80B will be referred to when referring to a specific disc among the two types of discs, and the disc 80 will be referred to when the discs are simply referred to as the generic name including the two types of discs. .

As shown in FIG. 5A, the disc 80A is a single-sided disc on which information is recorded / reproduced on one side of the information recording surface 81, and only one side of the information recording surface 81 is covered with a thickness t1. A glass 82 is provided. The cover glass 82 has a thickness t1 of 1.2 mm, which is twice as large as the cover glass of the disk 80B described later. The disk 80A has a uniform thickness throughout.
At the center of the disk 80, a metal hub 84 having a hole through which the shaft 65 of the spindle motor 60 passes is provided.

On the other hand, the disc 80B is a double-sided disc on which information is recorded / reproduced on both sides of the information recording surface 81, as shown in FIG. 5B, and has a thickness t2 on both sides of the information recording surface 81. A cover glass 82 is provided. The thickness t2 of the cover glass 82 of the disk 80B is 0.6 mm.
Therefore, it is half the thickness of the cover glass 82 of the disk 80A. The central portion of the spindle motor 60, which is in contact with the turntable 66, is thick, and the thickness of one side of the information recording surface 81 is the disk 80 described above.
It has the same thickness t1 as A. Hubs 84 are provided on both sides of this thickened central portion.

Further, the mounting portions of the disc 80A and the disc 80B to the spindle motor 60 are the same.
Therefore, it can be mounted on one spindle motor.

The spindle motor 60 on which the disk 80 is mounted has a base 61 fixed to the deck base 1 as shown in FIGS. 5 (A) and 5 (B). A wound yoke 62 is attached. The shaft 65 is attached to the base 61 via a bearing 64 and is rotatably supported.
A turntable 66 is fixed to the shaft 65. A recess is formed on the upper surface of the turntable 66, and a chucking magnet 67 that attracts the hub 84 of the disk 80 by a magnetic force is provided on the bottom of the recess. Disc 8 placed on turntable 66
The magnet 0 is provided with a magnet 68 on the inner surface of a cylindrical turntable 66.
The rotation driving force of the turntable 66 is generated in association with the rotation number 3.

As shown in FIGS. 5A and 5B, the disk 80 is placed on the turntable 66 with the recording / reproducing surface facing down. At that time, the hole of the hub 84 fits the shaft 65, so that the hub 84 is automatically positioned. The disk 80 placed on the turntable 66 is fixed by magnetically attracting the hub 84 to the chucking magnet 67.

As shown in FIG. 5A, the cover glass 8
When recording / reproducing the thick disk 80A of 2, the cover glass 32 is removed from the optical path of the light emitted from the objective lens 5. The optical system including the objective lens 5 is designed so that the spherical aberration becomes minimum when the thickness of the cover glass 82 is t1. Therefore, the light emitted from the objective lens 5 is
The light spot 88 directly incident on the disk 80A and formed on the information recording surface 81 has the minimum spherical aberration.

As shown in FIG. 5B, the cover glass 8
When recording / reproducing the thin disk 80B of two, the cover glass 32 is arranged on the optical path of the light emitted from the objective lens 5. The cover glass 32 is made of, for example, a material (for example, polycarbonate) of the cover glass 82 of the disk 80, has the same refractive index as the cover glass 82, and its thickness t3 satisfies t2 + t3 = t1 (1) Is set.

The optical system including the objective lens 5 is designed so that the spherical aberration is minimized with respect to the disk 80A having the cover glass 82 with the thickness t1.
Since the thickness t3 of the cover glass 82 and the thickness t2 of the cover glass 82 satisfy the relationship of the equation (1), the thickness of the cover glass 82 is t.
It is equivalent to the case of 1. Therefore, the light emitted from the objective lens 5 passes through the cover glass 32 and then passes through the disk 80.
A light spot 8 formed on the information recording surface 81 is incident on the disk 80B having a cover glass 82 with a thickness t2.
The spherical aberration of 8 is the minimum.

As described above, with respect to the disc 80B having the thin cover glass 82, the cover glass 32 having a reduced thickness is disposed between the objective lens 5 and the disc 80, whereby the spherical surface of the light spot is obtained. The aberration is corrected to be the minimum.

The cover glass 32 has a refractive index of the disk 80.
The refractive index of the cover glass 82 may be different. In that case, the thickness t3 of the cover glass 32 is adjusted so that the spherical aberration of the light spot 88 is minimized.

In the optical system of this embodiment, the light emitted from the objective lens 5 is focused on the same height (Z-direction position) regardless of the presence or absence of the cover glass 32. On the other hand, the disk 80
In A, the thickness t1 of the cover glass 82 is constant, including the central portion in contact with the turntable 66. On the other hand, in the disk 80B, the thickness t2 of the cover glass 82 at the portion where information is actually recorded / reproduced is the disk 8
Although it is thinner than 0 A, the thickness of one side of the information recording surface 81 is t1 in the central portion which contacts the turntable 66. Therefore, as can be seen from FIG.
The height (position in the Z direction) of the information recording surface 81 is the same when 0A is mounted and when the disc 80B is mounted.

As described above, since the height of the information recording surface 81 is constant regardless of the type of the disc 80, the disc 80
It is not necessary to change the position of the objective lens 5 in the Z direction depending on the type. Therefore, the stroke of the movement of the objective lens 5 in the Z direction may be minimum, and the support drive mechanism of the objective lens 5 for focusing in the Z direction may be small.

[Second Embodiment] A second embodiment will be described with reference to FIG. In the figure, the same members as those described in the first embodiment are designated by the same reference numerals. The present embodiment is another aberration correction mechanism 40 that replaces the aberration correction mechanism 30 of FIG.

The aberration correction mechanism 40 has a cover glass 32 for correcting spherical aberration and a support mechanism for movably supporting the cover glass 32. The support mechanism has plates 43 and 44 fixed to both ends of the cover glass 32. The plates 43 and 44 are rotatably attached to attachment portions 1a and 1b on the deck base 1 about a shaft 47. There is. The mounting portion 1b is formed with a hole 48 through which light moving between the fixed optical system and the movable portion passes.

Further, the support mechanism includes a drive source (not shown) for moving the cover glass 32, such as the plate 4.
It has a linear solenoid that oscillates 3, 44 and a rotary solenoid that rotates a shaft 47. The cover glass 32 is inserted in the optical path as shown by the solid line, or as shown by the imaginary line. It is removed from the street.

In this embodiment, the cover glass 32 is located farther from the disc 80 when it is off the optical path than when it is on the optical path. Cover glass 32
Is placed on the optical path when the cover glass 82 of the disc 80 is thin, and in this case, the surface of the disc 80 is located farther from the objective lens 5 than the thick disc 80A of the cover glass 82. The distance between the objective lens 5 and the disc 80B is as wide as that.

Therefore, the cover glass 32 may be arranged by utilizing the interval of the spread. That is, as the cover glass 82 is thinner than the thin disk 80B having the cover glass 82, the gap between the disk 80B and the objective lens 5 is widened, and the cover glass 32 is placed in this gap.
May be inserted. In this configuration, the gap between the disc 80A and the objective lens 5 is narrower than that of the thick disc 80A having the cover glass 82. In this case, however, the cover glass 32 is located away from the disc 80A, so that it hits the disc 80A. Don't worry.

With this structure, the size of the entire device in the height direction (Z direction) can be further reduced. In the case of this configuration, in order to avoid the contact between the cover glass 32 and the disc 80, the cover glass 32 is usually located at a position away from the disc as drawn by an imaginary line, and a function of discriminating the type of the mounted disc 80 is provided. It is desirable that the cover glass 32 is provided so that the cover glass 32 moves to the optical path only when it is confirmed that the disk 80 is the thin disk 80B of the cover glass 82.

[Third Embodiment] A third embodiment will be described with reference to FIG. In the figure, the same members as those described in the first embodiment are designated by the same reference numerals. The present embodiment is still another aberration correction mechanism that replaces the above-described aberration correction mechanisms 30 and 40.

The aberration correction mechanism of this embodiment is a disk 80
The correction optical element 52 for correcting spherical aberration due to the difference in the thickness of the cover glass and the linear solenoid 56 fixed to the deck base 1 for movably supporting the correction optical element 52 are provided, and the correction optical element is provided as necessary. 52 is inserted in the optical path between the fixed optical system 28 and the objective lens 5. Correction optical element 5
Reference numeral 2 is composed of a hologram element and an optical element composed of a powerless double-sided aspherical surface, and corrects only spherical aberration in the light from the light source.

For a disk 80A having a thick cover glass 82, the correction optical element 52 is moved in the direction of arrow A and is removed from the optical path. The optical system is designed so that the spherical aberration is minimized with respect to the thick disk 80 having the cover glass 82. Therefore, in this case, the spherical aberration of the light spot 88 formed on the information recording surface 81 is minimized.

On the contrary, for the disk 80B having the thin cover glass 82, the correction optical element 52 is inserted in the optical path. The correction optical element 52 corrects the light spot 88 formed on the information recording surface 81 so that the spherical aberration is minimized.

Various modifications can be made in addition to the above-described embodiments. For example, the thickness of the cover glass of the disc may be three or more types, and in that case, the correction optical elements of the types are arranged. Further, the disc may be any of a phase change disc, a magneto-optical disc, a compact disc and the like as long as it is an optical recording medium. The correction optical element may be any element as long as it corrects the spherical aberration of the light spot. Also, this support mechanism may be another.

[0058]

According to the present invention, since the support mechanism for movably supporting the correction optical element is fixed to the deck base, the weight and the center of gravity of the movable portion do not change depending on the position of the correction optical element. Therefore, the movable part has stable drive sensitivity and excellent controllability. Since it is not necessary to provide a space for the movable part to be located outside the optical recording medium, the entire structure of the information recording device can be made compact.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall configuration of an information recording / reproducing apparatus of a first embodiment of the present invention.

FIG. 2 is a sectional view of the information recording / reproducing apparatus of FIG.

FIG. 3 is a perspective view of a movable part shown in FIG.

FIG. 4 is an exploded perspective view of a movable part shown in FIG.

FIG. 5 is a diagram for explaining the structure of two types of disks and the operation of the device for each disk.

FIG. 6 is a diagram showing a configuration of an aberration correction mechanism of a second embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of an aberration correction mechanism of a third embodiment of the present invention.

[Explanation of symbols]

1 ... Deck base, 5 ... Objective lens, 6 ... Movable part, 32
... cover glass, 33, 34, 35 ... link, 36 ... solenoid.

Claims (1)

[Claims] 1. An information recording / reproducing apparatus for recording / reproducing information on / from a plurality of types of optical recording media having different thicknesses of a protective layer covering an information recording surface, wherein a fixed deck base and information recording / reproducing are provided. A light source that emits light for the purpose, an objective lens that collects the light emitted from the light source on the information recording surface of the optical recording medium, and a movable part that is movably provided with respect to the deck base.
Information provided with a movable part including an objective lens, a correction optical element for correcting spherical aberration due to a difference in thickness of a protective layer, and an insertion means for appropriately inserting the correction optical element into an optical path from a light source to an optical recording medium. In the recording / reproducing apparatus, the inserting means has a supporting mechanism for movably supporting the correction optical element, and the supporting mechanism is fixed to the deck base.