JP2003085817A - Optical pickup and disk driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize and make thin an optical pickup by arranging various kinds of optical components consisting a laser optical system so that the detecting direction of a tracking error of a photodetector roughly matches with the moving direction of reflected light at the time of tracking adjustment to a disk-like recording medium while securing a required optical path length of a laser beam from a laser irradiation means up to a signal surface of the disk-like recording medium. SOLUTION: In the optical pickup 100, an integrated optical element 104 is arranged so as to make the optical axis of the laser beam L1 from the laser irradiation means to a prism orthogonal to the radial direction of the disk-like recording medium 5 and the moving direction at the time of focus adjustment of an objective lens 122, and the prism 125 inside the integrated optical element, the photodetector and a rising mirror are arranged so as to roughly match the detecting direction of the tracking errors of the photodetectors 126 and 127 and the moving direction of the reflected light L2 at the time of the tracking adjustment to the disk-like recording medium.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for reducing the size and thickness of an optical pickup in an optical pickup and a disk drive device.

[0002]

2. Description of the Related Art There is a disk drive device for writing or reading an information signal to or from a disk-shaped recording medium such as an optical disk. Such a disc drive device moves in the radial direction (tracking direction) of the disc-shaped recording medium and irradiates the disc-shaped recording medium with a laser beam to write or read an information signal to or from the disc-shaped recording medium. Have an optical pickup for.

The above optical pickup generally includes a laser irradiation means (semiconductor laser element), a collimator lens,
It has various optical components constituting a light receiving and emitting optical system including a prism, a photodetector, an objective lens, etc., that is, a laser optical system.

FIG. 10 shows an example a of the conventional optical pickup described above. The optical pickup a has a moving base (chassis) b on which a laser beam incident is directed to a signal surface of a disc-shaped recording medium (not shown). Objective lens c for condensing, objective lens drive mechanism (biaxial actuator) d for movably supporting objective lens c for performing focusing adjustment and tracking adjustment, integrated optical element (laser coupler) e and raising mirror f Etc. are arranged.

By the way, with the recent miniaturization of the disk drive device, the miniaturization of the optical pickup itself is progressing. As the optical pickup becomes smaller, the space for arranging the laser optical system inside the optical pickup also becomes smaller, so the optical path length of the laser light from the laser irradiation means to the signal surface of the disk-shaped recording medium inevitably becomes shorter. However, there is a problem that this optical path length cannot be made shorter than a certain value.

That is, on the optical path of the laser beam from the laser irradiation means to the signal surface of the disk-shaped recording medium, a space for arranging various optical parts constituting the laser optical system is necessary, and further, the objective lens is focused. This is because a space for moving the incident laser light in the optical axis direction is also required for adjustment.

Therefore, like the optical pickup a, an integrated optical element e in which a laser irradiation means g, a prism h, a collimator lens (not shown), a photodetector and the like are enclosed in a semiconductor package as an integrated optical block.
It is effective to secure the required optical path length by using a mirror and arranging a rising mirror f at a position immediately before the objective lens c in the optical path of the laser beam, and to reduce the size. It is possible to arrange various optical components constituting the laser optical system on the optical path bent by the raising mirror f without waste in the arranged space of the optical pickup a.

However, in the optical pickup, the photodetector is irradiated with the reflected light (return laser light) reflected by the surface (signal surface) of the disk-shaped recording medium, and tracking error and focusing error are detected to perform tracking adjustment and focusing. Because adjustments are made,
Since it is necessary to make the detection direction of the tracking error on the photodetector and the moving direction of the reflected light at the time of tracking adjustment with respect to the disk-shaped recording medium substantially coincide with each other, the arrangement of various optical parts constituting the laser optical system is restricted. .

Therefore, in the optical pickup a,
As shown in FIG. 10, the moving direction of the return laser beam at the time of tracking adjustment with respect to the disc-shaped recording medium is the direction of arrow i in the figure because the optical path is bent by the rising mirror f, and therefore arrow j The laser coupler e having the direction of detecting the tracking error by the photodetector is arranged so that the optical path of the laser beam from the laser light emitting element g to the prism h is in the direction orthogonal to the surface of the disk-shaped recording medium, that is, as shown in the figure. In addition, it was necessary to arrange them vertically.

Therefore, in the optical pickup a,
By using the rising mirror f, it is possible to bend the optical path of the laser light and downsize it as a whole, but as described above, the longitudinal direction of the integrated optical element e in which the arrangement direction is restricted is limited. It was not possible to reduce the total thickness due to the limitation of the size. The term "thickness" as used herein refers to the dimension of the optical pickup in the direction orthogonal to the surface of the disk-shaped recording medium.

[0011]

In view of the above problems, the present invention detects a tracking error of a photodetector while securing a required optical path length of laser light from the laser irradiation means to the signal surface of the disk-shaped recording medium. It is an object to make the optical pickup smaller and thinner by making the direction substantially coincident with the moving direction of the reflected light at the time of tracking adjustment with respect to the disk-shaped recording medium and devising the arrangement of the laser coupler.

[0012]

In order to solve the above-mentioned problems, an optical pickup and a disk drive device according to the present invention are configured such that an optical pickup irradiates a laser irradiating means for irradiating a laser beam and a laser irradiating means irradiates the laser beam An integrated optical element including a prism that bends and bends and a photodetector that receives the laser light that has passed through the prism, an objective lens that focuses the incident laser light on the signal surface of the disk-shaped recording medium, and a laser irradiation unit that emits the laser light. A rising mirror that reflects the bent laser beam to the objective lens side and bends it, and at the same time reflects the reflected light from the disk-shaped recording medium that enters through the objective lens to the prism side and bends it, is arranged on the moving base. An objective lens drive mechanism having a fixed portion and a movable portion movably supported with respect to the fixed portion, The object lens drive mechanism has an objective lens attached to the movable portion, and the movable portion has a disc shape so that the laser light emitted through the objective lens is focused on the signal surface of the disc-shaped recording medium to form a spot. Focusing adjustment is performed by moving in the direction away from and contacting the signal surface of the recording medium, and the movable part is moved so that the position of the spot of the laser beam moves following the recording track on the signal surface of the disk-shaped recording medium. Tracking adjustment is performed by moving the integrated optical element from the laser irradiation means to the prism so that the optical axis of the laser light is the same as the moving direction of the moving base and the moving direction at the time of focusing adjustment of the objective lens. Arrange them so that they are orthogonal to each other, and place the prism, photodetector, and rising mirror in the integrated optical element The detection direction of the bets detector tracking error, the moving direction of the reflected light at the time of tracking adjustment with respect to the disc-shaped recording medium are those which are arranged so as to substantially coincide.

Therefore, according to the present invention, in the optical pickup and the disk drive device, the optical path of the laser beam is bent by the objective lens to secure the required optical path length, and the detection direction of the tracking error of the photodetector and the tracking with respect to the disk-shaped recording medium are tracked. It is possible to substantially match the moving direction of the reflected light at the time of adjustment.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION First, the outline of the present invention will be described.

According to the present invention, there is provided a laser irradiating means for irradiating a laser beam, a prism for refracting and bending an optical path of the laser beam irradiated by the laser irradiating means, and a photodetector for irradiating the laser beam passing through the prism. And an objective lens for collecting incident laser light and irradiating it onto the signal surface of the disk-shaped recording medium, and reflecting the optical path of the laser light emitted from the integrated optical element to the objective lens side. In a pickup and a disk drive device using the pickup, the pickup including a rising mirror that bends the optical path of reflected light from the disk-shaped recording medium that is incident through an objective lens and is reflected by the prism side, In the integrated optical element, the optical axis of the laser light from the laser irradiation means to the prism is the radius of the disk-shaped recording medium. Arranged such that in a direction perpendicular to the moving direction during focusing adjustment direction and the objective lens,
By arranging the prism, the photodetector, and the raising mirror in the integrated optical element so that the detection direction of the tracking error of the photodetector and the moving direction of the reflected light at the time of tracking adjustment with respect to the disk-shaped recording medium are substantially matched, The optical pickup is designed to be compact and thin.

Embodiments of the optical pickup, the disc drive device, and the method for adjusting the optical axis position of the laser light in the disc drive device according to the present invention will be described below with reference to the accompanying drawings.

In the following embodiments, for example, the present invention is a disk cartridge in which a disk-shaped recording medium (magneto-optical disk, optical disk, etc.) having a diameter of 64 mm is rotatably housed in a flat case body. The present invention is applied to a disc drive device for reproducing an information signal recorded on the disc-shaped recording medium or recording an information signal on the disc-shaped recording medium, and an optical pickup used in the disc drive device.

The disk drive device 1 is shown in FIGS.
As shown in FIG. 2, required members and mechanisms are arranged in the outer casing 2 having a thin box shape.

A laterally long rectangular insertion / removal opening 2a is formed on the front surface of the outer casing 2, and a door 2b for closing the insertion / removal opening 2a to prevent dust from entering is supported on the outer casing 2.

As described above, the disk cartridge 3 is formed by rotatably housing the disk-shaped recording medium 5 in the flat case body 4.

Therefore, the disk cartridge 3 is the outer casing 2
When it is inserted inside or when it is discharged from the outer casing 2, the door 2b is operated to open the insertion / removal opening 2a.

In the following description, when referring to the front, rear, up, down, left and right directions, in FIG. 1, the side of the outer casing 2 of the disk drive device 1 on which the insertion / removal opening 2a is formed is the front and the opposite direction is the same. Backward, the left and right directions shall mean the left and right directions toward the front defined above,
The upper and lower directions in FIG. 1 are the upper and lower directions. For reference, the arrow in each figure indicates the front (Fron
t), rear (Rear), left (Left), right (Right), upper (Upper), lower (Lower).

As shown in FIG. 1, operation buttons 6, 6, ... Assigned to various functions are arranged at appropriate positions on the outer casing 2 of the disk drive device 1, and these operation buttons 6, 6 ,. When the ... Is operated, for example, the reproduction operation, the stop of the operation, the change of the volume, the ejection of the disc cartridge 4 from the outer casing 2, and the like are executed.

In the outer casing 2, as shown in FIG.
A chassis 7 is arranged. A drive motor (spindle motor) (not shown) is arranged on the lower surface side of the chassis 7 substantially at the center, and the rotation shaft of the drive motor penetrates the chassis 7 and projects upward, and the disk table 8 is fixed to the rotation shaft. ing.

As shown in FIG. 2, the chassis 7 includes
The arrangement hole 7a is formed, and the disk table 8 is in a state of protruding above the upper surface of the chassis 7. Further, the lead screw 9 and the guide shaft 10 are arranged in parallel with each other on the lower surface side of the chassis 7. And
At a position corresponding to the arrangement hole 7a of the chassis 7, the optical pickup 100 is in the radial direction (radial direction or tracking direction) of the disc-shaped recording medium 5 mounted on the disc table 8, that is, as indicated by an arrow A in FIG. It is movably supported in the direction shown.

As shown in FIGS. 2 to 4, the optical pickup 100 includes various members required for the moving base 101.
That is, the objective lens driving mechanism 102 and the raising mirror 10
3, a laser coupler (integrated optical element) 104 and the like are arranged.

Further, in the optical pickup 100, the laser coupler 104 is arranged so that the optical axis of the laser beam from the laser irradiation means in the laser coupler 104 to the prism is in the radial direction of the disk-shaped recording medium 5 and the objective lens to be described later. The prism in the laser coupler 104, the photodetector, and the rising mirror 103 are arranged so as to be orthogonal to the moving direction at the time of adjustment.
The detection direction of the tracking error of the photo detector,
It is arranged so that the moving direction of the reflected light (return laser light) at the time of tracking adjustment with respect to the disk-shaped recording medium 5 substantially coincides with the moving direction.

As shown in FIGS. 3 and 4, the moving base 101 has a main portion 105 and bearing portions 106, 10 formed integrally with the front and rear end portions of the main portion 105, respectively.
7 and.

That is, as shown in FIG. 3, the bearing portion 106 located on the rear side of the main portion 105 is provided with a screw hole 106a penetrating the moving base 101 in the left-right direction, and the bearing portion 107 on the front side is provided. Is provided with a support groove 107a that extends in the left-right direction and opens toward the front.

The moving base 101, as shown in FIG.
The lead screw 9 is screwed into the screw hole 106a of the bearing 106, and the guide shaft 10 is inserted into the support groove 107a of the bearing 107.
Is slidably fitted to the chassis 7, and is movably supported by the chassis 7. The bearing portion 106 is fed by the lead screw 9 which is rotated by being driven by a stepping motor or the like (not shown), and the bearing portion 107 Is moved by sliding on the guide shaft 10. Therefore, the optical pickup 100 moves in the radial direction of the disc-shaped recording medium 5 within the arrangement hole 7a of the chassis 7.

The main portion 105 of the moving base 101 is also
As shown in FIG. 4, the shallow wall of the bottom wall 105a is a shallow rectangular container which is surrounded by the peripheral wall 105b on three sides except for the rear side of the bottom wall 105a which continues to the bearing portion 106 that engages with the lead screw 9. I'm making a difference.

The main part 105 of the moving base 101 is shown in FIG.
As shown in FIG. 2, the two ribs 10 extending in parallel to the left and right direction in a portion slightly rearward from the center of the bottom wall 105a.
8 and 108 are formed. Then, the rib 10
Semicircular notches 108a and 108a for holding the rising mirror 103 in a rotatable state are formed at positions substantially in the center of the left and right directions of 8 and 108. Further, an opening 105c is formed in the bottom wall 105a between the ribs 108 to avoid interference between the rising mirror 103 and the bottom wall 105a when the rising mirror 103 is held and the angle is adjusted. Has been done.

On the right side surface of the main portion 105 of the moving base 101, as shown in FIG. 4, positioning projections 109 and 110 protruding rightward and a circular shape penetrating the peripheral wall 105b in the left-right direction are formed. A transparent hole 111 is formed. These positioning protrusions 109 and 110 are used for the laser coupler 10.
4 is provided to define the approximate position of the laser coupler 104 when the main body 105 of the moving base 101 is attached. Also, the positioning protrusions 109 and 11
On the surface of the peripheral wall 105b, which is sandwiched by 0s, the mounting position of the laser coupler 104, such as the positions of the light transmitting hole 111 and an emission hole described later through which laser light is emitted from the inside of the laser coupler 104, is more strict. In order to define the above, for example, positioning means (not shown) such as a large number of positioning projections are formed. In this case, the laser coupler 104 is also formed with positioning means (not shown) corresponding to the above positioning means.

As shown in FIGS. 3 and 4, the objective lens driving mechanism 102 has a support base (fixed portion) 112 and a movable portion 113 supported by the support base 112.
The support base 112 is composed of a base portion 114, yokes 115 and 115 which are respectively erected upward from both left and right edges of the base portion 114, and a support shaft 116 which is protruded upward from substantially the center of the base portion 114. .

As shown in FIG. 4, the yokes 115, 115 are formed by bending the front and rear ends 115a, 115a toward each other so as to have a U-shape when viewed from above. Are opposed to each other.

As shown in FIG. 3, magnets 117 and 117 are fixed to the inner surfaces of the yokes 115 and 115 facing each other by adhesion or the like. still,
The magnets 117 and 117 are arranged such that the surfaces on the opposite sides have the same polarity.

As shown in FIGS. 3 and 4, the movable portion 113 is composed of a resin bobbin 118 to which the required members are attached. The bobbin 118 has a main body 11
9 and a lens holder 120 integrally projecting rearward from the main body 119.

The main body 119 of the bobbin 118 is shown in FIG.
As shown in FIG. 5, the upper wall 119a and the side wall 119b formed so as to surround the periphery of the upper wall 119a are integrally projected downward from the front and left and right side edge portions of the upper wall 119a. A balancer mounting portion 119c for attaching a balancer (not shown) having an appropriate shape is integrally formed on the lower edge of the front side wall 119b of the main body 119 so as to project forward. In addition, in a substantially central portion of the lower surface of the upper wall 119a, the supported cylindrical portion 1 having a cylindrical shape protruding downward.
19d is provided. Further, a coil body 121 including a focusing coil and a tracking coil is attached to the lower surface of the main body 119 of the bobbin 118.

As shown in FIGS. 3 and 4, the lens holder portion 120 has an objective lens 122 having a predetermined shape.
Is held with the outer edge portion thereof being pressed by the ring-shaped holding frame 123.

As shown in FIG. 3, the movable portion 113 has the support shaft 116 of the base portion 114 inserted into the supported cylindrical portion 119d of the main body portion 119 of the movable portion 113, whereby It is supported so as to be slidable in the axial direction and rotatable about the axis of the support shaft 116.

The objective lens driving mechanism 102 configured as described above is attached and fixed to the moving base 101. That is, the base 114 of the objective lens driving mechanism 102
Is a main part 105 of the moving base 101, as shown in FIG.
The front rib 108 and the peripheral wall 105b in the part of the front
The bottom surface of the base part 114 is fixed to the bottom wall 105a of the main part 105 by an appropriate means such as adhesion. Then, the objective lens 122 supported by the movable portion 113 of the objective lens driving mechanism 102 comes to be positioned substantially directly above the raising mirror 103 arranged in the main portion 105 of the moving base 101.

In the state where the objective lens driving mechanism 102 is attached to the moving base 101, the moving direction of the movable portion 113 is such that the axial direction of the support shaft 116 is on the surface (signal surface 5a) of the disk-shaped recording medium 5. The focusing direction is the direction in which the support shaft 116 separates and contacts, and the direction around the support shaft 116 is the tracking direction that is a direction that crosses the recording tracks of the disk-shaped recording medium 5.

Then, the objective lens driving mechanism 102 is attached to the moving base 101, and the support shaft 11 of the base 114 is attached.
In a state where the movable portion 113 is supported by 6,
As shown in FIG. 3, the magnets 117 and 117 are positioned immediately outside the movable portion 113 so as to sandwich the bobbin 118 from the left and right.

Further, in this state, the bobbin 118 (coil body 121) of the movable portion 113 is connected to the drive circuit via the movable base 101 by a flexible printed wiring board (not shown), and the coil body 121 is appropriately energized. Also generates a magnetic field to move the movable portion 113 in the focusing direction and the tracking direction,
Focusing adjustment and tracking adjustment are performed.

As shown in FIG. 4, the rising mirror 103 includes a reflecting portion 103a formed in a flat plate shape and the reflecting portion 1
Columnar support shaft portion 10 protruding outward from the side surface of 03a
3b and 103b.

In the conventional optical pickup, the raising mirror is fixed on the moving base so that the reflecting surface has a predetermined angle.
The rising mirror 103 is the rib 10 of the moving base 101.
The support shaft portion 10 is provided in the notches 108a and 108a of the reference numerals 8 and 108.
It is supported by fitting 3b and 103b respectively. In this state, the raising mirror 103 is rotatable in the direction indicated by arrow B in FIGS. 8 and 9 with the support shaft portions 103b and 103b as the rotation axes. As will be described later in detail, the raising mirror 103 is rotated to adjust the angle of the reflection surface 103c, which is the surface of the reflection portion 103a, to an optimum angle, and thereafter, is attached to the main portion 105 of the moving base 101 by an adhesive. Fixed.

The laser coupler 104 has a laser light emitting element, which is a laser irradiating means, and a light receiving element packaged as an integrated optical block, whose internal structure is schematically shown in FIG. A laser light emitting element (laser diode chip) 124, a prism 125, a first photodetector (hereinafter abbreviated as “PD”) 126, and a second PD 127 provided on a semiconductor substrate.
Etc., and these are contained in a horizontally long substantially rectangular semiconductor package 104a.

Strictly speaking, the prism 125 is a combination of two prisms each formed of two different types of media (birefringent medium and homogeneous medium). Omit it. Prism 12
As shown in FIGS. 5 and 6, reference numeral 5 has a trapezoidal block shape in which one side is formed with an inclined surface to serve as a reflection surface 125a. Further, the prism 125 is arranged such that the reflection surface 125a faces the laser light emitting element 124 side, and at least the portion of the reflection surface 125a irradiated with the laser light emitted from the laser light emitting element 124 is a polarization separation semi-transmissive film. (BS film) is coated.

The bottom surface 125b of the prism 125
Is coated with a non-polarizing beam splitter (NPBS film) on the portion corresponding to the position of the first PD 126, and is coated with an anti-reflection film (AR film) on the portion corresponding to the position of the second PD 127. ing. Furthermore,
An upper surface 125c facing the bottom surface 125b of the prism 125
Is coated with a total reflection film. Further, the first PD 126 and the second PD 127 are the same as those shown in FIGS.
As shown in FIG. 3, each is formed so as to have a plurality of sensor units.

That is, as shown in FIGS. 6 and 7, the first PD 126 is divided into four sensor sections 126a, 126.
a second PD 127 having b, 126c and 126d.
Has two sensor blocks 127a and 127b, and each of the sensor blocks 127a and 127b is divided into three sensor units 127c, 127d and 1 respectively.
27e, 127f, 127g, and 127h.
Then, the first PD 126 and the second PD 127 respectively have sensor units 126a, 126b, 126c, 126.
d and the sensor portions 127c, 127d, 127e, 127f, 127g of the sensor blocks 127a and 127b.
And 127h are arranged in contact with the bottom surface 125b of the prism 125.

Laser coupler 1 having the above configuration
In 04, the laser light L1 emitted from the laser light emitting element 124 is reflected by the reflection surface 125a of the prism 125 and the optical path is bent by approximately 90 °, and as shown in FIG. 5, the emission hole 104b of the semiconductor package 104a.
Is emitted from the outside. Further, as will be described later in detail, the return laser light L2 reflected and returned by the signal surface 5a of the disk-shaped recording medium 5 enters the inside of the laser coupler 104 through the emission hole 104b of the semiconductor package 104a, and the inside of the prism 125. Is incident on.

Then, the laser coupler 104 is attached to the main portion 105 of the moving base 101 as shown in FIGS. That is, the laser coupler 104 is positioned by the positioning protrusions 109 and 110 and the above-mentioned positioning means on the peripheral wall 105b of the main portion 105 sandwiched by the positioning protrusions 109 and 110, and is fixed by adhesion or the like. It When the laser coupler 104 is attached to the main portion 105 of the moving base 101,
The light transmitting hole 111 of the moving base 101 and the laser coupler 104
The position of the light emission hole 104b is aligned with that of the light emission hole 104b. By disposing the laser coupler 104 on the moving base 101 as described above, it is possible to make the optical pickup 100 thinner as a whole.

In the optical pickup 100 having the above-described structure, the laser light L1 emitted from the laser light emitting element 124 in the laser coupler 104 is reflected by the reflecting surface 125a of the prism 125 as described above and is emitted from the emitting hole. The light is emitted from 104b to the outside. Then, the laser beam L1 emitted from the emission hole 104b of the laser coupler 104 passes through the light transmitting hole 111 of the moving base 101 as shown in FIG. 8, and the bottom wall 1 of the main portion 105 of the moving base 101.
05a, the rising mirror 103 bends the optical path of the laser beam L1 by approximately 90 ° and heads upward substantially vertically, and the movable portion 1 of the objective lens driving mechanism 102 is moved.
The light enters the objective lens 122 supported by 13 and is condensed and irradiated onto the signal surface 5a of the disk-shaped recording medium 5 to form a spot.

The laser light L1 focused and irradiated on the signal surface 5a of the disk-shaped recording medium 5 is reflected by the signal surface 5a of the disk-shaped recording medium 5 to become the returned laser light L2, which is an optical path opposite to the above, that is, , Which is transmitted vertically through the objective lens 122, is reflected by the rising mirror 103, and the optical path is bent by approximately 90 ° to move the movable base 101.
The light is irradiated in parallel with the bottom wall 105a of the main portion 105 of the main body 105 and returns to the inside of the laser coupler 104 through the light transmitting hole 111 of the moving base 101 and the emitting hole 104b.

The return laser beam L2 entering the laser coupler 104 is refracted and transmitted through the reflecting surface 125a of the prism 125 as shown in FIG.
5 inside the first PD 126 on the bottom surface 125b.
A spot 128 is formed on the inner surface of the portion where the is arranged.

The first P on the bottom surface 125b of the prism 125
The return laser beam L2 having the spot 128 formed on the inner surface of the portion where the D126 is arranged partially passes through the bottom surface 125b, and the sensor portions 126a and 126b of the first PD 126.
It is irradiated onto 126c and 126d and detected as a signal.

The spot 12 is formed on the inner surface of the bottom surface 125b of the prism 125 where the first PD 126 is arranged.
Part of the return laser beam L2 that forms 8 is reflected at that portion, is reflected again at the inner surface of the upper surface 125c of the prism 125, and has two spots on the inner surface of the portion of the bottom surface 125b where the second PD 127 is arranged. 129 and 129 are formed.

That is, the spot 12 is formed on the inner surface of the bottom surface 125b of the prism 125 where the second PD 127 is arranged.
The return laser light L2 forming the light beams 9 and 129 has a bottom surface 125.
b through the sensor block 127 of the second PD 127
a, 127b of the respective sensor units 127c, 126d, 126
e, 127f, 127g, 127h are illuminated and detected as a signal.

Strictly speaking, the return laser beam L2 incident on the prism 125 is transmitted through the BS film coated on the reflecting surface 125a, and has two polarization directions due to the portion formed of the birefringent medium. Of the bottom surface 125 due to the deviation of the separated light components.
Although there are two spots 128 formed on the inner surface of the portion where the first PD 126 of b is arranged, this will be ignored and treated as one here. When the return laser light L2 separated into the two light components reaches the portion of the inner surface of the bottom surface 125b where the second PD 127 is arranged, the distance between the return laser light L2 separated into the two light components is further increased. Therefore, two spots 129 and 129 are formed.

The information recorded on the disk-shaped recording medium 5 is read by the detection signals from the first PD 126 and the second PD 127, respectively.
Tracking errors and focusing errors are detected.

The tracking error is caused by the first PD 126.
Four sensor parts 126a, 126b, 126c and 1 of
It is detected by utilizing the difference between the respective detection signals by 26d.

That is, the arrangement direction of the four sensor sections 126a, 126b, 126c and 126d of the first PD 126 is on the straight line connecting the intersections of the 0th order light and the ± 1st order light of the diffraction pattern of the return laser light L2. Since it is almost symmetrical as the center,
Each sensor unit 126a, 126b, 126c and 126d
By comparing the detection signals according to the above, it is possible to detect the positional deviation of the spot 128 incident on the PD 126, and thus it is possible to perform the tracking adjustment.

Further, as for the focusing error, since the return laser beam L2 separated into two is incident on the two sensor blocks 127a and 127b of the second PD 127, respectively, the two sensor blocks 127a and 127b.
Are treated as one and are operated by the so-called D-3DF method to detect the detection signal of the first PD 126 and the second PD 126.
It is detected by detecting the focus signal based on the detection signal of the PD 127.

That is, when in focus, the return laser beam L2 is focused on the total reflection film coated on the upper surface 125c of the prism 125, and the first PD
126 and spots 128 and 12 on the second PD 127
The diameters of 9 and 129 are the same. When the focus is out of focus, the first PD 126 and the second PD
The spots 128 at 127 and 129 and 129 have different diameters.

By the way, in an optical pickup, generally, optical components such as a rising mirror and a laser coupler are fixed on a moving base by adhesion or the like. When the mounting angle of the optical component with respect to the moving base is deviated, the optical axis of the laser beam is deviated, and the incident angle of the laser beam with respect to the signal surface of the disk-shaped recording medium deviates from a right angle. The incident angle when the return laser light reflected by the signal surface of the disk-shaped recording medium is incident on the PD in the prism also deviates from the predetermined angle. Due to the deviation of the incident angle of the return laser light with respect to the PD, the position of the spot incident on the sensor portion of the PD also shifts, and the signal level of the return laser light that can be detected by the PD becomes low. The deviation of the incident angle of the laser light particularly affects the tracking performance and the like of the optical pickup, and thus becomes a problem in the radial direction of the disk-shaped recording medium, that is, the tracking direction.

Therefore, in the conventional optical pickup, a so-called mounting reference surface whose dimensional accuracy is strictly controlled is set so that the optical components such as the raising mirror and the laser coupler have predetermined positions and postures. The surface is positioned to minimize the deviation of the mounting angle of these optical parts, and to minimize the deviation of the incident angle of the laser light from the right angle on the signal surface of the disk-shaped recording medium. It was However, it is very difficult to reduce the deviation of the mounting angle of the optical component to zero, and there is no means for correcting the deviation of the mounting angle of the optical component.

Further, if the moving base to which the optical parts are attached is downsized due to the downsizing of the optical pickup in recent years, the above-mentioned attachment reference surface is naturally reduced, so that the dimensional accuracy of the attachment reference surface should be obtained. Was getting more difficult. Even if the moving base to which the optical parts are attached is downsized due to the downsizing of the optical pickup, if the dimensional accuracy of the attachment reference plane is to be kept as it is, the cost of the moving base components will be high. Further, there arises a problem that the yield at the time of production of a moving base and the like also deteriorates.

Therefore, according to the present invention, the mounting accuracy of various optical components constituting the optical system is not dependent only on the dimensional accuracy of the components such as the moving base, and the cost of the components such as the moving base is reduced. The optical axis tilt of the laser beam generated by the mounting error of the optical parts by absorbing the mounting error of various optical parts, especially the tilt of the optical axis in the radial direction of the disk-shaped recording medium The correction can be made by adjusting the angle of the reflecting surface of the rising mirror which is reflected and is incident on the objective lens.

That is, in the optical pickup 100, with respect to the attachment of the laser coupler 104 to the moving base 101, the mounting reference surface formed by the positioning projections 109 and 110 and the peripheral wall 105b of the main portion 105 between them. The cost of parts of the moving base 101 is suppressed by not relying on the dimensional accuracy of the laser beam, and the deviation of the incident angle of the laser beam L1 generated by the mounting error of the laser coupler 104 with respect to the signal surface 5a of the disk-shaped recording medium 5, that is,
The tilt of the optical axis is corrected by rotating the raising mirror 103 to adjust the angle of the reflecting surface 103c to an optimum state.

A method of adjusting the optical axis of the laser beam L1 in the optical pickup 100 will be described below.

Reflecting surface 103 of the rising mirror 103
For the angle adjustment of c, as shown in FIGS. 8 and 9, the laser coupler 104 is set to the positioning protrusion 10 of the moving base 101.
It is performed after attaching and fixing to the outer surface of the peripheral wall 105b of the main portion 105 between 9 and 110 and before attaching the objective lens driving mechanism 102 to the moving base 101.

The adjustment of the irradiation angle of the laser beam L1, that is, the position adjustment of the spot formed on the signal surface 5a of the disk-shaped recording medium 5 by the laser beam L1 in the tracking direction is performed.
Specifically, for example, using an appropriate jig (not shown) or the like, the optical pickup 100 before the attachment of the objective lens driving mechanism 102 is actually used (the objective lens driving mechanism 10).
No. 2 is attached and the signal is read from the disc-shaped recording medium 5), and the oscilloscope display is displayed while observing the output signal level of the first PD 126 on which the return laser beam L2 incident on the oscilloscope is displayed. PD1
As shown in FIG.
When the raising mirror 103 is appropriately rotated in the direction indicated by the arrow B as shown in FIG.
The positions of 6b, 126c, and 126d can be adjusted to be centered, whereby the incident angle of the laser beam L1 with respect to the signal surface 5a of the disk-shaped recording medium 5 can be made a right angle. Then, the rising mirror 103 is fixed by adhesion after the angle of the reflecting surface 103c is adjusted.

That is, the sensor section 126 of the first PD 126.
The spot 128 of the return laser beam L2 focused on a, 126b, 126c, and 126d is shown in FIG. 7A when the optical axis of the laser beam L1 is inclined with respect to the signal surface 5a of the disk-shaped recording medium 5. ), The sensor unit 126 is indicated by the spots 128a and 128b indicated by a broken line and a dashed line.
a, 126b, 126c, and 126d are shifted in the direction of arrow C, and when the incident angle of the laser beam L1 on the signal surface 5a of the disk-shaped recording medium 5 is optimum, like a spot 128 shown by a solid line, Sensor parts 126a, 12
6b, 126c and 126d are centrally located.

The rotation direction of the rising mirror 103 is
Laser light L on the signal surface 5a of the disk-shaped recording medium 5
The displacement of the position of the spot 128 on the sensor units 126a, 126b, 126c and 126d of the first PD 126 due to the inclination of the optical axis of 1 is the spots 128a and 12
8b appears as a deviation in the direction of arrow C and must be determined so that the spot 128 can be moved in the direction of arrow C by adjusting the angle of the reflection surface 103a of the rising mirror 103.

Therefore, in the optical pickup 100, the inclination of the optical axis of the laser beam L1 caused by the deviation of the mounting angle of the optical component, which is originally very difficult to be zero, is reflected by the laser beam L1. The raising mirror 103 that is incident on the objective lens 122 is rotated to rotate the reflecting surface 103c.
Can be absorbed and corrected by changing the angle of the laser coupler 104 attached to the moving base 101.
Also, the mounting accuracy of the rising mirror 103 is adjusted to the moving base 10.
By not relying on the dimensional accuracy of No. 1, it is possible to reduce the cost at the time of manufacturing the moving base 101 and also to improve the yield at the time of manufacturing the optical pickup. Then, by substantially eliminating the deviation of the incident angle of the laser beam L1 to the signal surface 5a of the disk-shaped recording medium 5, that is, the inclination of the optical axis, the return laser reflected by the signal surface 5a of the disk-shaped recording medium 5 is eliminated. The deterioration of the level of the signal extracted from the light L2 can be eliminated.

As described above, in the optical pickup 100, the mounting cost of the optical components such as the laser coupler 104 does not depend on the dimensional accuracy of the moving base 101, so that the cost of the moving base 101 can be reduced, and The inclination of the optical axis of the laser beam L1 caused by the mounting error of the parts,
In particular, the inclination of the optical axis in the radial direction of the disk-shaped recording medium 5 is corrected by adjusting the angle of the reflecting surface 103c of the rising mirror 103 that reflects the laser beam L1 and makes it enter the objective lens 122. It is a thing. That is, the inclination of the optical axis of the laser beam L1 in the radial direction of the disk-shaped recording medium 5 is as shown in FIG.
Four sensor units 126a, 126 of the first PD 126
b, 126c and 126d, the shifts 128a and 12 of the spot 128 of the return laser beam L2 in the direction of arrow C
By arranging the arrangement attitude of the laser coupler 104 on the moving base 101 so as to appear as 8b, and adjusting the angle of the reflecting surface 103c of the rising mirror 103,
Four sensor units 126a, 126 of the first PD 126
offset spots 128a on b, 126c and 126d
And 128b can be the normal spot 128 so that the raising mirror 10 on the moving base 101
3 is set and the direction for adjusting the angle of the reflecting surface 103c is set.

As described above, the inclination of the optical axis of the laser beam in the radial direction of the disk-shaped recording medium is determined by the first PD.
Four sensor parts 126a, 126b, 126c and 1 of
26d, the optical axis of the return laser beam L2 appears as a deviation in the direction of arrow C, the inclination of the optical axis of the laser beam L1 is corrected by adjusting the angle of the reflecting surface 103c of the rising mirror 103, and the return laser beam L2 is returned. Spot of 128
Four sensor sections 126a, 126 of the first PD 126 of
The optical pickup 100 capable of correcting the deviation in the arrow C direction on b, 126c and 126d.
In the basic configuration of (1), it is possible to secure the required optical path length of the laser light L1 and change only the arrangement of the laser coupler 104 and the raising mirror 103 on the moving base 101 without changing the basic configuration. Is.

As described above, in the optical pickup 100, the laser coupler 104 is attached to the moving base 1.
No. 01 is arranged along the right peripheral wall 105b of the main portion 105, and the optical axis of the laser beam L1 from the laser light emitting element 124 to the prism 125 moves in the radial direction of the disk-shaped recording medium 5 and the focusing lens 122 during focusing adjustment. The photodetector 1 is arranged so that it is orthogonal to the direction.
The detection direction of the tracking error 26 and the moving direction of the return laser beam L2 at the time of tracking adjustment with respect to the disk-shaped recording medium 5 are substantially matched, and the raising mirror 103 causes the laser beam L1 and the return laser beam L2 to be made.
Since the optical path is bent to secure the required optical path length, the optical pickup 100 can be downsized and thinned.

Further, in the disk drive device 1 and the optical pickup 100, it is originally very difficult to make the laser light zero, and the laser light on the signal surface of the disk-shaped recording medium is caused by the deviation of the mounting angle of the optical parts. The tilt of the optical axis of L1 can be corrected by adjusting the angle of the reflecting surface by rotating the rising mirror that reflects the laser beam L1 and makes it enter the objective lens. The mounting accuracy when mounting the laser coupler and the raising mirror does not depend on the dimensional accuracy of the moving base, which enables cost reduction during manufacturing of the moving base, and also improves the yield during manufacturing of the optical pickup. It is also possible to reduce the size of the optical pickup because it is not necessary to keep the dimensional accuracy of the moving base etc. high. It becomes easy.

The laser beam L1 is reflected by the signal surface 5a of the disc-shaped recording medium 5 by substantially eliminating the deviation of the incident angle of the laser beam L1 on the signal surface 5a of the disc-shaped recording medium 5, that is, the inclination of the optical axis. It is also possible to eliminate the deterioration of the level of the signal extracted from the return laser beam L2.

The specific shapes and structures of the respective portions shown in the above-mentioned embodiments are merely examples of the implementation of the present invention. The scope should not be limitedly interpreted.

[0082]

As is apparent from the above description, in the optical pickup of the present invention, a predetermined member is provided on the moving base which is movably supported in the radial direction of the disk-shaped recording medium mounted on the disk table. It consists of being placed,
An optical pickup for irradiating a disk-shaped recording medium with a laser beam, the laser irradiating unit for irradiating the laser beam, a prism for refracting and bending the laser beam irradiated by the laser irradiating unit, and a laser passing through the prism. An integrated optical element having a photodetector for receiving light, an objective lens for converging the incident laser light on the signal surface of the disk-shaped recording medium, and reflecting the laser light emitted from the laser irradiation means to the objective lens side. A rising mirror that bends and bends the reflected light from the disk-shaped recording medium that is incident through the objective lens by reflecting the reflected light toward the prism side, and a fixed portion arranged on the moving base and moving with respect to the fixed portion. And an objective lens drive mechanism having a movable part supported so that the objective lens is mounted on the movable part. At the same time, the movable part is moved in the direction in which the laser beam emitted through the objective lens is focused on the signal surface of the disk-shaped recording medium to form a spot and is brought into contact with the signal surface of the disk-shaped recording medium. Focusing adjustment is performed by moving the movable part in the moving direction of the moving base so that the position of the spot of the laser beam moves following the recording track on the signal surface of the disk-shaped recording medium. And then
The integrated optical element is arranged so that the optical axis of the laser light from the laser irradiation means to the prism is orthogonal to the moving direction of the moving base and the moving direction at the time of focusing adjustment of the objective lens to prevent tracking error of the photodetector. The prism, the photodetector and the rising mirror in the integrated optical element are arranged so that the detection direction and the moving direction of the reflected light at the time of tracking adjustment with respect to the disk-shaped recording medium are substantially coincident with each other. .

Therefore, the integrated optical element is arranged so that the optical axis of the laser light from the laser irradiation means to the prism is orthogonal to the radial direction of the disk-shaped recording medium and the moving direction of the objective lens during focusing adjustment. Then, the detection direction of the tracking error of the photodetector and the moving direction of the reflected light at the time of tracking adjustment with respect to the disk-shaped recording medium are made to substantially coincide with each other, and the optical path of the laser light and the reflected light is bent by the raising mirror to reduce the required optical path length. Since it is ensured, the optical pickup can be made smaller and thinner.

Further, the disc drive device of the present invention comprises a disc table on which a disc-shaped recording medium is mounted and rotated, and a moving base which is supported so as to be movable in the radial direction of the disc-shaped recording medium mounted on the disc table. A disk drive device comprising: a predetermined member placed on the disk drive; and an optical pickup for irradiating a disk-shaped recording medium with laser light. Means and a prism for refracting and bending the laser light irradiated by the laser irradiation means, and a photodetector for receiving the laser light passing through the prism, and an incident laser light for the signal surface of the disk-shaped recording medium. The objective lens that focuses the light on the laser and the laser light emitted from the laser irradiation means are reflected to the objective lens side. A rising mirror that bends by reflecting the reflected light from the disk-shaped recording medium that is incident through the objective lens on the prism side and moves relative to the fixed portion arranged on the moving base and the fixed portion. An objective lens drive mechanism having a movable part supported so as to be possible,
The objective lens drive mechanism has an objective lens attached to the movable portion, and the movable portion has a disc shape so that the laser light emitted through the objective lens is focused on the signal surface of the disc-shaped recording medium to form a spot. Focusing adjustment is performed by moving in the direction away from and contacting the signal surface of the recording medium, and the movable part is moved so that the position of the spot of the laser beam moves following the recording track on the signal surface of the disk-shaped recording medium. Tracking adjustment is performed by moving the integrated optical element from the laser irradiation means to the prism so that the optical axis of the laser light is the same as the moving direction of the moving base and the moving direction at the time of focusing adjustment of the objective lens. Arrange them so that they are perpendicular to each other, and detect the tracking error of the photodetector and the disc-shaped recording medium. The moving direction of the reflected light at the time of tracking adjustment is to be substantially coincident, characterized in that a prism and photodetector and the rising mirror in integrated optical elements.

Therefore, the integrated optical element is arranged so that the optical axis of the laser beam from the laser irradiation means to the prism is orthogonal to the radial direction of the disk-shaped recording medium and the moving direction of the objective lens during focusing adjustment. Then, the detection direction of the tracking error of the photodetector and the moving direction of the reflected light at the time of tracking adjustment with respect to the disk-shaped recording medium are made to substantially coincide with each other, and the optical path of the laser light and the reflected light is bent by the raising mirror to reduce the required optical path length. Since it is ensured, the optical pickup can be made smaller and thinner, which can contribute to the size reduction of the disk drive device.

According to the invention described in claims 2 and 4, the raising mirror is rotatably supported so that the angle of the reflecting surface can be changed, and the angle of the reflecting surface is changed. Since the irradiation angle of the laser beam applied to the signal surface of the disk-shaped recording medium can be changed to the moving direction of the moving base, it is originally very difficult to reduce it to zero due to the deviation of the mounting angle of the optical components. The tilt of the optical axis of the laser light on the signal surface of the disk-shaped recording medium can be corrected by changing the angle of the reflection surface by rotating the raising mirror that reflects the laser light and makes it enter the objective lens. Therefore, the mounting accuracy of the integrated optical element and the rising mirror does not depend on the dimensional accuracy of the mounting portion such as the moving base, and the cost can be reduced at the time of manufacturing the optical pickup. Can improve the yield in the manufacture of Kkuappu, also, may be easily miniaturized optical pickup does not need to maintain a high mounting accuracy of the optical component.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention together with FIGS. 2 to 9, and is a perspective view schematically showing a disk drive device.

FIG. 2 is a perspective view schematically showing an internal configuration of a disk drive device.

FIG. 3 is a perspective view schematically showing an optical pickup.

FIG. 4 is an exploded perspective view schematically showing a configuration of an optical pickup.

FIG. 5 is a side view schematically showing a configuration of an integrated optical element.

FIG. 6 is a perspective view schematically showing the structure of a prism.

FIG. 7 is a diagram schematically showing a state of spots of laser light irradiated on a first photodetector and a second photodetector.

FIG. 8 is a vertical cross-sectional view of a main part schematically showing how the optical axis of laser light is moved by adjusting the angle of a raising mirror.

FIG. 9 is a perspective view of an optical pickup that schematically shows how the angle of a rising mirror is adjusted.

FIG. 10 is a perspective view schematically showing the configuration of an example of a conventional optical pickup.

[Explanation of symbols]

1 ... Disk drive device, 5 ... Disk recording medium,
5a ... Signal surface (of disc-shaped recording medium), 100 ... Optical pickup, 101 ... Moving base, 102 ... Objective lens drive mechanism, 103 ... Standing mirror, 103c ... Reflecting surface (of rising mirror), 104 ... Integrated type Optical element, 1
12 ... Fixed part, 113 ... Movable part, 122 ... Objective lens,
124 ... Laser irradiation means, 125 ... Prism, 126 ...
Photodetector 127 ... Photodetector

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Claims (4)

[Claims] 1. A predetermined member is placed on a moving base which is movably supported in a radial direction of a disk-shaped recording medium mounted on a disk table, and laser light is applied to the disk-shaped recording medium. Which is an optical pickup for irradiating a laser beam, a laser irradiating unit for irradiating the laser beam, a prism for refracting and bending the laser beam irradiated by the laser irradiating unit, and a photodetector for receiving the laser beam passing through the prism. An integrated optical element provided, an objective lens for converging the incident laser light on the signal surface of the disk-shaped recording medium, a laser light emitted from the laser irradiation means is reflected toward the objective lens side, and the objective lens is A rising mirror that reflects the reflected light from the disk-shaped recording medium that is incident via An objective lens driving mechanism having a fixed portion arranged on the moving base and a movable portion movably supported with respect to the fixed portion, wherein the objective lens driving mechanism has an objective lens attached to the movable portion. By moving the movable part in a direction away from and in contact with the signal surface of the disk-shaped recording medium so that the laser light emitted through the objective lens is focused on the signal surface of the disk-shaped recording medium to form a spot. Focusing adjustment is performed, and tracking adjustment is performed by moving the movable portion in the moving direction of the moving base so that the position of the spot of the laser beam moves following the recording track on the signal surface of the disk-shaped recording medium. In the integrated optical element, the optical axis of the laser beam from the laser irradiation means to the prism is the moving direction of the moving base and the objective lens. The prism, the photodetector, and the raising mirror in the integrated optical element are arranged so as to be orthogonal to the moving direction during the focusing adjustment, and the tracking error detection direction of the photodetector and the tracking adjustment with respect to the disk-shaped recording medium are adjusted. An optical pickup characterized in that the optical pickup is arranged so that the moving direction of reflected light at the time substantially matches. 2. The rising mirror is rotatably supported so that the angle of the reflecting surface can be changed, and the moving direction of the reflected light that moves by changing the angle of the reflecting surface of the rising mirror is a photodetector. The optical pickup according to claim 1, wherein the optical pickup is made to substantially coincide with the above focusing error detection direction. 3. A disk table on which a disk-shaped recording medium is mounted and rotated, and a predetermined member is mounted on a moving base supported movably in the radial direction of the disk-shaped recording medium mounted on the disk table. A disk drive device, which comprises an optical pickup for irradiating a disc-shaped recording medium with laser light, the optical pickup comprising laser irradiating means for irradiating laser light and the laser irradiating means. Means for refracting and bending the laser light emitted by the means, an integrated optical element including a photodetector for receiving the laser light that has passed through the prism, and the incident laser light is collected on the signal surface of the disk-shaped recording medium. The objective lens that emits light and the laser light emitted from the laser irradiation means are reflected toward the objective lens side to bend and A rising mirror that reflects the reflected light from the disk-shaped recording medium entering through a lens to the prism side and bends it, and a fixed portion arranged on the moving base and movable relative to the fixed portion. An objective lens drive mechanism having a supported movable part, wherein the objective lens drive mechanism has an objective lens attached to the movable part, and a laser beam emitted through the objective lens is a signal surface of a disc-shaped recording medium. Focusing adjustment is performed by moving the movable part in a direction away from and in contact with the signal surface of the disk-shaped recording medium so as to form a spot by condensing on the disk-shaped recording medium. Tracking adjustment is performed by moving the movable part in the moving direction of the moving base so as to follow the recording track on the signal surface. The integrated optical element is arranged such that the optical axis of the laser light from the laser irradiation means to the prism is orthogonal to the moving direction of the moving base and the moving direction during focusing adjustment of the objective lens, The prism, the photodetector, and the rising mirror in the integrated optical element are arranged so that the detection direction of the tracking error of the photodetector and the moving direction of the reflected light during tracking adjustment with respect to the disk-shaped recording medium are substantially aligned. Disk drive device. 4. The rising mirror is rotatably supported so that the angle of the reflecting surface can be changed, and the moving direction of the reflected light that moves by changing the angle of the reflecting surface of the rising mirror is a photodetector. 4. The disk drive device according to claim 3, wherein the disk drive device is configured to substantially match the above focusing error detection direction.