JPH09180222A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup device having a very quick responsiveness by reducing the number of parts. SOLUTION: This device 20 holds a swing arm 31 to be freely turned by a bearing device 32 at a middle part in the direction of the length, fitting an optical head device 33 including an objective lens 332 at the tip of the swing arm 31, and fitting a turn-drive device 35 to turn the swing arm at the other end. When a light beam is defocused, the objective lens 332 is driven to be controlled in the direction of its optical axis, and in the case of detracking, the swing arm 31 is driven to be controlled by applying a tracking control signal in accordance with the tracking error to a turning coil 353 of the turning drive device 35.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup used for reproducing an information signal recorded on an optical disk, recording an information signal on a magneto-optical disk, or reproducing an information signal therefrom. It relates to the device.

[0002]

2. Description of the Related Art Conventionally, a CD player or MD for reproducing a music information signal recorded on a CD (compact disc)
An optical head device is installed in an optical disc device such as an MD recorder which records a music information signal on a (mini disc) and reproduces the music information signal from the mini disc, and irradiates a desired recording track of the optical disc with a light beam. In order to allow it to move, an arm rotatably supported at one end (hereinafter,
"Swing arm"), and a tracking control device for controlling an objective lens mounted on the optical pickup body to precisely track the desired recording track on the optical disc on the swing arm. An optical pickup device comprising a focus control device for controlling an objective lens mounted on the optical pickup main body in order to precisely focus a light beam for irradiating the desired recording track of the optical disc on the swing arm. Some are used.

The swing arm is rotatably supported by a bearing device at an intermediate portion in the longitudinal direction, and a swing drive device (not shown) composed of a yoke, a magnet, a coil and the like at one end of the swing arm. Is mounted, and the swing arm is horizontally rotated by applying a predetermined control signal thereto, and the light beam from the light beam emitting element incorporated in the optical head device is applied to a predetermined recording track. I am letting you.

As shown in the enlarged view of FIG. 4, the optical head device 10 includes an objective lens 11 arranged to face the optical disc D, a sealing package body 12, and a sealing glass plate 13. Light-beam light-emitting element 14 sealed in
And an optical signal detecting element 1 in which a half mirror 15 is arranged at one end at an inclination angle of 45 ° with the light beam emitting element 14.
6, the package 12 for sealing, and the objective lens 11
It is composed of an optical path bending prism 17 and the like which are disposed between and. The objective lens 11, the sealing package body 12, the optical path bending prism 14 and the like are fixed to a fixing member 18.

The light beam emitting element 14 includes, for example,
A laser diode or the like may be used, and the light beam L emitted from the light beam emitting element 14 is reflected downward by the half mirror 15 and enters the optical path bending prism 17 disposed below. The incident light beam L is bent by the optical path bending prism 17 in parallel with the light beam L emitted from the light beam emitting element 14, but in the opposite direction, and then bent to the objective lens 11. The light beam L incident on the objective lens 11 is focused on the signal recording surface of the optical disc D. The light beam L reflected by the signal recording surface of the optical disc D passes through the opposite optical path and is detected by the optical signal detecting element 16 to detect an information signal and a control signal.

Such an optical head device 10 is usually
It is incorporated in the optical pickup device 1 as shown in FIG. The built-in optical head device 10 is configured to be driven and controlled by a biaxial actuator 4 configured around a magnet 3 fixed to a part of the upper surface of a plate-shaped swing arm 2 serving as a yoke portion. ing. For example, four leaf springs (only two are shown in FIG. 5 are shown so that the optical head device 10 can swing in parallel with the support portion 5 fixed to the upper surface of one end of the yoke portion 2. ), Etc., and the optical pickup device 1 configured as described above is disposed so as to face the optical disc D in the optical disc device. An example of this type of optical pickup device 1 and biaxial actuator 2 is described in Japanese Patent Laid-Open No. 62-40627 "Optical Pickup Device".

The optical disk device is provided with a focus control device (not shown) and a tracking control device (not shown), and the focus control device is the optical disk D.
When the light beam L is not focused on the signal recording surface (hereinafter, abbreviated as “defocus”), the state is changed to the optical signal detecting element 1 of the optical pickup device 1.
6, a focus control signal formed on the basis of the detected focus error signal is supplied to a focus coil (not shown) of the biaxial actuator 4 so that the light beam L is focused on the signal recording surface. The objective lens 11 is driven and controlled in the optical axis direction thereof, and the tracking control device is in a state where the light beam L illuminating the signal recording surface of the optical disc D deviates from the recording track (hereinafter, abbreviated as “detrack”). At that time, the state is detected by the optical signal detection element 16 of the optical pickup device 1, and a tracking control signal formed based on the detected tracking error signal is applied to a tracking coil (not shown) of the biaxial actuator 4. The objective lens 11 is supplied and controlled to control the light beam L so as to track the recording track. There.

However, the optical head device 10 requires the encapsulating package body 12 for enclosing the light beam emitting element 14 and the optical signal detecting element 16 and the encapsulating glass plate 13, and the optical path bending prism 17. Since the objective lens 11, the encapsulating package body 12, and the fixing member 18 for fixing the optical path bending prism 17 are required, the optical head device 10 according to the related art has a large number of parts and is accordingly heavy. Become. Also, this optical head device 1
At 0, the optical path bending prism 17 is arranged in parallel with the objective lens 11 and the optical signal detection element 16, so that the thickness increases and becomes large.

The large and heavy optical head device 1 thus constructed
The optical pickup device 1 in which 0 is fixed to the support portion 5 by the swing support member 6 cannot be driven with high responsiveness by the drive means such as the biaxial actuator 4.

Therefore, the applicant of the present invention has proposed an invention of an optical pickup device having a light weight optical head device having a small number of parts, which solves such a problem, as disclosed in Japanese Patent Application No. 7-31.
Filed No. 2128 on November 30, 1995. The optical pickup device is shown in FIGS.

In this optical pickup device 1A, the substrate 7
And an optical head device 20 fixed to the upper surface of the tip portion thereof.
And a drive coil 3B fixed to the upper surface of the base end portion of the substrate 7, for example, constituting a part of the biaxial actuator 4.
A plate-shaped swing arm 2 serving as a yoke portion, a magnet 3A that constitutes another part of the biaxial actuator 4 fixed to a part of the upper surface of the swing arm 2, and one end of the swing arm 2. A support part 5 fixed to the upper surface of the base plate, and the base end part and the drive coil 3B are supported on the support part 5 so as to be swingable in parallel,
It is composed of a swing support member 6 such as four leaf springs (only two are shown in FIG. 6). The other end of the swing arm 2 is supported, driven, and controlled by a rotation drive device (not shown), as in the prior art.

As shown in FIG. 8, an electric wiring circuit 7A such as a power supply circuit connected to a power supply and a signal output circuit for taking out various signal outputs is formed on the surface of the substrate 7. A through hole 7B is formed in the base end of the substrate 7 so that the tip of the magnet 3A can pass therethrough. Therefore, the magnet 3A protrudes from the through hole 7B and loosely enters the central portion of the drive coil 3B.

The optical head device 20 is shown in FIGS.
As shown in detail by enlarging in FIG.
An optical signal detecting element 16 having a half mirror 15 at one end at an inclination angle of 45 ° with the light beam emitting element 14, and an optical signal detecting element 16 disposed above the half mirror 15 and integrated with the sealing member 8. And the objective lens 11 that is mounted in a fixed manner.

The light beam emitting element 14 and the optical signal detecting element 16 are directly bonded to the electric wiring circuit 7A of the substrate 7 while maintaining a predetermined optical relationship position. The cup-shaped sealing member 8 is fixed to the substrate 7 so as to cover the light beam emitting element 14 and the optical signal detecting element 16 bonded in this way. The objective lens 11 can be integrally molded with the sealing member 8 from glass, plastic, or the like, for example.

The light beam emitting element 14 may be, for example, a laser diode, and the light beam L emitted from the light beam emitting element 14 is reflected upward by the half mirror 15 and is reflected by the objective lens 11. Incident,
It converges on the signal recording surface of the optical disc D. Then, the light beam L reflected by the signal recording surface of the optical disc D passes through the opposite optical path and is detected by the optical signal detecting element 16, and the focus error signal and the tracking error signal are transmitted through the electric wiring circuit 7A to the optical disc apparatus main body. It is configured to be led out to the focus control device and the tracking control device provided in the. Power is supplied to the light beam emitting element 14 and the optical signal detecting element 16 through the electric wiring circuit 7A.

[0016]

As described above, the optical pickup device 1A according to the embodiment of the invention described above can reduce the number of parts of the optical head device and can be made smaller and lighter. Therefore, control such as focusing and tracking can be performed. If you do
Although the optical pickup device 1A can be made to respond agilely compared to the conventional technique, the objective lens 1
The biaxial actuator 4 is still used for driving and controlling the optical head device 20 including the optical disc drive 1.

The biaxial actuator 4 requires a focus magnet and a focus coil for driving the objective lens 11 in the optical axis direction thereof, and a tracking magnet and a tracking coil for tracking the objective lens 11 on the recording track of the optical disc D. Since these materials are made of copper wire or steel, they are comparatively heavy parts among various parts forming the optical head devices 10 and 20, and the optical pickup device cannot respond sufficiently agilely. It is a thing. Therefore, the present invention is intended to solve such a problem, and an object thereof is to obtain an optical pickup device having an extremely fast responsiveness by further reducing the number of parts to reduce the weight.

[0018]

Therefore, an optical pickup device of the present invention comprises a swing arm, a bearing device for rotatably supporting the swing arm, and a rotation drive device for rotating the swing arm. , An optical head device comprising an objective lens attached to an end of the swing arm and movably in the optical axis direction, a focus drive device for moving the objective lens in the optical axis direction, and a light beam And an optical signal detection element that receives a reflected light beam from the signal recording surface of the optical disc, and supplies a focus error signal detected by the optical signal detection element to the focus drive device. Then, the objective lens is driven in the optical axis direction,
The tracking error signal detected by the optical signal detection element is used to control the rotary drive device to control the swing arm, thereby solving the above problem.

Therefore, the optical pickup device of the present invention is
Since the structure can be simplified and especially the number of parts of the optical head device can be reduced, the optical head device is significantly lighter than that of the prior art, and can be more agile.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an optical pickup device of the present invention will be described with reference to FIGS. FIG. 1 is a conceptual perspective view showing an embodiment of the optical pickup device of the present invention, and FIG. 2 is an A of the optical pickup device shown in FIG.
FIG. 3 is a sectional view taken along line A, and FIG. 3 is a sectional view of an embodiment in which the configuration of the optical pickup device shown in FIG. 2 is partially modified and the optical pickup device is applied to a magneto-optical pickup device.

Reference numeral 30 indicates an optical pickup device which is an embodiment of the present invention. The optical pickup device 30 includes a swing arm 31, a bearing device 32 that supports the swing arm 31 in an intermediate portion of the swing arm 31 so that the swing arm 31 can freely rotate, and one end portion of the swing arm 31. An arranged optical head device 33,
A laser coupler 34 disposed in an intermediate portion between the optical head device 33 and the bearing device 32, and the other end of the swing arm 31 on the opposite side of the optical head device 33 with the bearing device 32 interposed therebetween. And a rotation drive device 35 for driving the swing arm 31.

The swing arm 31 is in the form of a slender arm as a whole, and has a structure in which various parts constituting the optical pickup device described later can be attached, for example, a metal plate is processed by sheet metal or the like. A mounting base 312 for mounting the overwrite head device 42 shown in the embodiment described with reference to FIG. 3, which is cut and raised at the base end of the swing arm 31 to which the rotation drive device 35 is mounted. Are formed.

The bearing device 32 includes a fixed shaft 321 implanted in the substrate B of the main body of the optical disk device and the fixed shaft 321.
The swing arm 31 is rotatably supported with respect to the substrate B so as to be rotatable in a horizontal state.

The optical head device 33 includes a focus control device 331 that moves an objective lens 332, which will be described later, toward the signal recording surface of the optical disc D, an objective lens 332 fixed on the focus control device 331, and the objective lens 332. The raising mirror 333 arranged below the lens 332 and the focus control device 331 and fixed on the swing arm 31 and the focus control device 331 are supported horizontally by two plate springs 3341, and the plate spring The other end of 3341 is fixed, and the supporting device 334 is composed of a supporting base 3342 fixed on the swing arm 2 and the like. The focus control device 331 includes a yoke 311 mounted on the tip of the swing arm 31, a magnet 3311 fixed to the inner surface of the swing arm 31, a coil bobbin 3312 disposed between the magnets 3311, and a peripheral surface of the coil bobbin 3312. A magnetic circuit is configured with the focus coil 3313 wound around the focus coil 3313, and the focus coil 3313 is a uniaxial actuator that is vertically movable.

The laser coupler 34 is a circuit board 34.
1. A light beam light emitting element 342 such as a laser diode directly bonded to the electronic circuit wiring formed on the surface of No. 1 and an optical signal detection element arranged in a predetermined positional relationship with the light beam emitting element 342 and directly bonded to the electronic circuit wiring. 343
And a bending mirror 344 and the like arranged below the laser coupler 34 and fixed on the swing arm 31 (FIG. 2).

The rotation driving device 35 is provided with a yoke 351 fixed to the upper surface of the substrate B, a magnet 352 fixed thereon, and below the swing arm 31 so as to face the magnet 352. A magnetic circuit is configured with the rotating coil 353 that is formed, and the objective lens 332 is provided with the swing arm 31 around the bearing device 32.
Of the optical disc D is rotated so as to be sent to a recording track on the optical disc D to be recorded or reproduced.

Next, the operation of the optical pickup device 30 will be described. Light emitting device 342 of the laser coupler 34
2, the light beam L emitted downwardly is reflected by the bending mirror 344 and reaches the rising mirror 333 existing on the left side in a horizontal state.
At 33, the light enters the upper objective lens 332 and converges on the signal recording surface of the optical disc D. Then, the light beam L reflected by the signal recording surface of the optical disc D passes through the opposite optical path and is projected onto a plurality of light receiving portions constituting the optical signal detecting element 343.

When the light beam L from the objective lens 332 is defocused on the signal recording surface of the optical disc D, a detection output signal representing a focus error signal is generated from the light receiving portion of the optical signal detection element 343, and the light beam L is emitted. When detracking from the recording track, a detection output signal representing a tracking error signal is generated from the light receiving portion of the optical signal detection element 343, and these detection output signals are respectively passed through the electronic circuit wiring formed on the circuit board 341. Servo matrix mounted on the optical disk unit
It is configured to be led to an amplifier (not shown).

In the servo matrix amplifier, a focus control signal and a tracking control signal corresponding to the focus error signal and the tracking error signal are respectively generated under a predetermined arithmetic expression. This focus control signal is the focus coil 3 of the focus control device 331.
It is supplied to 313, and the objective lens 332 is moved in the vertical direction of the arrow (FIG. 2), and the light beam L from the objective lens 332 is controlled so as to be focused on the signal recording surface of the optical disc D. Further, the tracking control signal is sent to the rotation driving device 3
5 to the swing coil 353, and the swing arm 31
Is finely rotated about the bearing device 32, and the light beam L from the objective lens 332 is controlled to track the recording track of the optical disc D. The optical pickup device 30 of the present invention thus focuses and tracks the light beam L.

FIG. 3 shows a modification of the optical pickup device 30 and an optical pickup device 40 in which it is applied to a magneto-optical disk device. That is, the structure of the main part of the optical pickup device 40 is the same as that of the optical pickup device 30.
Since the configuration is the same as the above, those components will be denoted by the same reference numerals and description thereof will be omitted, but the structural difference is that the position of the bearing device 32 and the rotation drive device 35 is different. It has a structure in which is replaced. With this configuration, the stroke of the swing arm 31 can be made larger than that of the optical pickup device 30. Therefore, the swing arm 31 can access a predetermined recording track with a slight rotation.

In the optical pickup device 40, a support arm 41 is fixed on a mount 312 formed at the base end of the swing arm 31, and the magnetic head is attached to the tip of the support arm 41. The overwrite head 42 is attached and is configured so as to be rotated and controlled integrally with the swing arm 31. Therefore, the overwrite head 42
The magnetic field formed by 1 and the focal position of the light beam L formed by the objective lens 332 do not deviate.

The optical head device 33 includes an objective lens 33.
2. Focus control device 331 and raising mirror 33
Since it is composed of 3 lasers, it is extremely lightweight as compared with the optical pickup device of the prior art, but within the allowable range of responsiveness, the laser coupler 3 is provided in the optical head device 33.
4 may be incorporated. That is, it is configured as the optical head device shown in FIG. 7 which is the invention of the above application. When the optical head device is configured with such a structure, the bending mirror 344 and the rising mirror 333 can be omitted, and the number of parts can be further reduced.

[0033]

As described above, according to the optical pickup device of the present invention, the structure thereof can be simplified, and particularly, the number of parts of the optical head device can be reduced. Therefore, the optical head device and the entire optical pickup device can be reduced. Can be significantly reduced in weight compared to the prior art, and thus can be made to respond faster. Therefore, it is possible to easily follow the high-speed rotation of the optical disc of the optical disc device in which the optical disc rotates at a higher speed than the swing-arm type optical pickup device of the related art.

Further, since the optical pickup device of the present invention adopts the swing arm system, there is no lens shift with respect to the optical axis in the tracking direction, which is an optical advantage.
Furthermore, in the case of the optical pickup device 40 for the magneto-optical disk device shown in FIG. 3, since the magnetic field formed by the overwrite head and the focus position of the light beam formed by the objective lens do not shift, the overwrite head The magnetic field range can be reduced, and the power consumption can be reduced.
As described above, according to the optical pickup device of the present invention, various excellent effects can be obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual perspective view showing an embodiment of an optical pickup device of the present invention.

2 is a cross-sectional view of the optical pickup device shown in FIG. 1 taken along the line AA.

FIG. 3 is a sectional view of an embodiment in which the configuration of the optical pickup device shown in FIG. 2 is partially modified and the optical pickup device is applied to a magneto-optical pickup device.

FIG. 4 is a sectional view schematically showing a conventional optical pickup device.

5 is a schematic cross-sectional view of an optical element used in the optical pickup device shown in FIG.

FIG. 6 is a schematic sectional view of an optical pickup device of the present invention.

7 is a cross-sectional view schematically showing an optical element used in the optical pickup device shown in FIG.

8 is a top view of the optical element shown in FIG. 2 as seen from above with the optical disk removed.

[Explanation of symbols]

30 Optical pickup device which is the first embodiment of the present invention 31 Swing arm 311 Yoke 312 Mounting base 32 Bearing device 33 Optical head device 3311 Magnet 3312 Coil bobbin 3313 Focus coil 332 Objective lens 333 Standing mirror 334 Supporting device 3341 Leaf spring 34 Laser coupler 341 Circuit board 342 Light beam light emitting element 343 Optical signal detecting element 344 Bending mirror 35 Rotation drive device 351 Yoke 352 Magnet 40 Optical pickup device 41 according to the second embodiment of the present invention 41 Support arm 42 Overwrite head

Claims (4)

[Claims] 1. A swing arm, a bearing device that rotatably supports the swing arm, a rotation drive device that rotates the swing arm, and a swing drive device that is attached to an end portion of the swing arm and extends in the optical axis direction. An optical head device composed of an movably mounted objective lens, a focus drive device for moving the objective lens in the optical axis direction, a light beam emitting element for generating a light beam, and reflection from a signal recording surface of an optical disc. An optical signal detecting element for receiving a light beam is provided, and a focus error signal detected by the optical signal detecting element is supplied to the focus driving device to drive the objective lens in the optical axis direction, The swing drive device is controlled by a tracking error signal detected by a signal detection element to control the swing arm. Optical pickup device. 2. The electronic circuit wiring is formed on the surface of the swing arm, and the optical head device except at least the objective lens is connected and fixed to the electronic circuit wiring. The optical pickup device described in. 3. In the optical head device, only the objective lens is supported so as to be movable in the optical axis direction, and other components are fixed to the swing arm. The optical pickup device according to claim 1. 4. The optical head device includes an objective lens,
A light beam emitting element and an optical signal detecting element are built in,
2. The optical pickup device according to claim 1, wherein the objective lens is movably supported in the optical axis direction, and the light beam emitting element and the optical signal detecting element are connected to electronic circuit wiring.