JPH10241198A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate fixing of optical components and to suppress resonance by ensuring rigidity by arranging a light source, lenses, and the like, on a frame for holding metallic components, e.g. members for dissipating heat generated from the light source made of synthetic resin through insert molding. SOLUTION: A heat dissipation plate 11 for holding metallic components is made in a frame 1 through insert molding. A light emitting/receiving composite element 2 is arranged fixedly on the heat dissipation plate 11 which conducts heat generated from the light source 4 of the light emitting/receiving composite element 2 and dissipates the heat to the outside of a pickup unit. The heat dissipation plate 11 is held such that the side fringe part thereof faces the outside of the side face part of the frame 1. A system for bending a luminous flux from the light source 4 to pass through mirrors 12, 13 and an objective lens 14 thus focusing the luminous flux on the recording face of a disc is built in the frame 1. Since a biaxial actuator 15 is insert molded for the frame 1, complification and increase in the size of the optical pickup can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of an optical pickup device for writing or reading information signals on an optical recording medium such as an optical disk.

[0002]

2. Description of the Related Art Hitherto, an optical disk or a magneto-optical disk has been proposed as an optical recording medium, and an optical pickup device for writing or reading an information signal on or from such an optical disk or a magneto-optical disk has been proposed. This optical pickup device, as shown in FIG.
The frame 101 includes a light source such as a laser diode, and various optical devices for condensing a light beam emitted from the light source on the surface (signal recording surface) of a signal recording layer of an optical disk or a magneto-optical disk. ing. The frame 101 has an optical block 102 formed of a metal material (for example, zinc) and incorporating a light source and a photodetector, and a base 103 formed of a synthetic resin material and holding the optical block 102. It is configured. The optical block 102 is attached to the base 103 by bonding or the like. A two-axis actuator 104 mounted on the base 103 is mounted on the base 103.
The objective lens 105 supported so as to be able to move is provided.

In this optical pickup device, a light beam emitted from a light source is converged by an objective lens 105 onto a signal recording surface of an optical disk or a magneto-optical disk. The light beam condensed on the signal recording surface is based on the information signal recorded on the signal recording layer on the signal recording surface,
The light intensity and the polarization direction are modulated and reflected. The light beam reflected by the signal recording surface is detected by a light detector such as a photodiode built in the optical block unit 102.

The base 103 has a bearing hole 106 and a support claw 107. In a recording / reproducing apparatus, a support shaft (main shaft) 108 is inserted through the bearing hole 106, and the support claw 107 is inserted into an edge of a support plate 109. Are engaged and are supported so as to be movable along the edges of the support shaft 108 and the countershaft 109. Base unit 103
Is provided with a feed gear unit 110. Base part 1
Reference numeral 03 moves along the support shaft 108 by transmitting a driving force of a motor (not shown) to the feed gear unit 110 via a transmission gear that meshes with the feed gear unit 110. The optical pickup device is moved along a support shaft 108 so that an objective lens 105 supported by a biaxial actuator 104 is opposed to an optical disk or a magneto-optical disk mounted on a recording / reproducing device. The optical disk and the magneto-optical disk are moved in the radial direction.

[0005] The biaxial actuator 104 includes a base 1
3 and a magnetic yoke 111 which is integrally erected on the base. A magnet is attached to the magnetic yoke section 111. A lens holder supported on a support block provided on the base unit via a flexible transfer arm is provided on the base unit. The objective lens 105 and the drive coil are attached to this lens holder. The objective lens 105 includes the optical block unit 1
It is supported at a position where a light beam from a light source emitted from the light source 02 enters. The coil is located in a magnetic field formed by the magnet and the magnetic yoke 111. In the two-axis actuator 104, when a driving current is supplied to the coil, the lens holder is moved in the two-axis direction with respect to the base, and the objective lens 105 is moved in the optical axis direction (focus) of the objective lens 105. Direction) and a direction perpendicular to the optical axis (tracking direction). In this way, the objective lens 104 moved and operated by the biaxial actuator 104 moves following the recording track on the signal recording surface of the optical disk or the magneto-optical disk.

[0006]

In the above-described optical pickup device, the base and the optical block 102 having the magnetic yoke 111 constituting the biaxial actuator 104 are bonded to the base 103. It is attached by means such as screws and screws. Therefore, in manufacturing this optical pickup device, there is a complicated manufacturing due to a large number of components such as the base portion and the optical block portion 102. Also, in this optical pickup device, it is difficult to reduce the size of the device configuration because of the large number of components.

Here, it is considered that the entire frame 101 is made of a metal material. However, if the entire frame 101 is made of a metal material, it is difficult to reduce the weight, and it is not possible to facilitate the manufacturing of the frame 101 and to reduce the cost.

Further, it is conceivable that the entire frame 101 is made of a synthetic resin material. However, if the entire frame 101 is made of a synthetic resin material, it will not be possible to satisfactorily radiate the heat generated by the light source to the outside. That is, especially when this optical pickup device is used as a device for writing (recording) an information signal on an optical recording medium, the amount of heat generated by the light source increases, and this heat is sufficiently radiated to the outside. It becomes difficult. In order to suppress a rise in temperature due to such a large amount of heat, it is necessary to separately attach a metal part exclusively for heat radiation, which complicates the configuration of the optical pickup device.

If the entire frame 101 is made of a synthetic resin material, sufficient rigidity cannot be secured.
Further, since the weight of the frame 101 is reduced, a variation in the balance (variation in the position of the center of gravity) depending on the mounting position of the metal component such as the biaxial actuator 104 and the light source is increased, and the entire optical pickup device is unbalanced (for example, In such a state that the position of the center of gravity of the whole exists at the end portion). With such an unbalanced configuration, there is a possibility that complicated mode resonance may occur when the moving operation is performed along the support shaft 108 or when the objective lens 105 is moved and operated. It becomes difficult to maintain the characteristics.

Therefore, the present invention has been proposed in view of the above-mentioned circumstances, and the magnetic yoke and the optical components can be easily mounted without increasing the complexity and size of the device. Is facilitated, and the heat generated from the light source can be sufficiently radiated to the outside.
An object of the present invention is to solve the problem of providing an optical pickup device in which sufficient rigidity is ensured and the overall balance is improved so that complicated mode resonance does not occur.

[0011]

In order to solve the above-mentioned problems, an optical pickup device according to the present invention comprises a frame made of synthetic resin material and holding metal parts by insert molding, and a frame attached to the frame. A light source; and an objective lens disposed on the frame and condensing a light beam emitted from the light source on a signal recording surface of an optical recording medium.

According to the present invention, in the optical pickup device, the metal component is a heat radiating member for radiating heat generated by the light source with light emission to the outside.

Further, according to the present invention, in the above optical pickup device, the metal component is a magnetic yoke constituting an actuator for movably supporting the objective lens on the frame and moving the objective lens by electromagnetic force. It is what you have decided.

According to the present invention, in the optical pickup device, the metal component serves as a balance weight for adjusting the position of the center of gravity of the entire frame.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, an optical pickup device according to the present invention is configured as a device for writing and reading information signals to and from a magneto-optical disk using a magneto-optical disk as an optical recording medium.

This optical pickup device has a frame 1 as shown in FIG. The frame 1 is formed by injection molding means of a synthetic resin material, and is formed by insert-molding a metal component as described later. This insert molding
The injection molding of a synthetic resin material is performed after a metal component is fixed in a mold used for injection molding in advance.

A composite light emitting and receiving device 2 having a laser diode as a light source is mounted on the frame 1. As shown in FIG. 2, the composite light-emitting and light-receiving element 2 includes a light source (laser diode) 4 and light-receiving elements (photodiodes) 5, 6 formed on the same semiconductor substrate 3.
Is configured. The light source 4 is provided on a heat sink unit 7 provided on the semiconductor substrate 3 so that the light flux emission direction is parallel to the upper surface of the semiconductor substrate 3. On the semiconductor substrate 3, a prism 8 is disposed on the light receiving elements 5 and 6. The light beam emitted from the light source 4 is deflected by 90 ° by being reflected by the inclined surface of the prism 8, and is emitted to the outside of the light emitting / receiving composite element 2.
Then, as described later, the light beam reflected by the signal recording surface of the magneto-optical disk and returned to the light emitting / receiving composite element 2 enters the prism 8 and is received by the light receiving elements 5 and 6. The composite light-emitting and light-receiving element 2 is configured by housing a semiconductor substrate 3 in a case 9. The case 9 is configured such that an upper surface side from which a light beam emitted from a light source is emitted is opened, and the upper surface side is closed by a transparent plate 10.

In the frame 1, a heat radiating plate 11, which is a metal component and a heat radiating member, is held by insert molding. The light emitting and receiving composite element 2 is attached to the frame 1 by being installed on the heat sink 11.
The heat radiating plate 11 conducts heat generated by the light source 4 of the light emitting / receiving composite element 2 with light emission and radiates heat to the outside of the optical pickup device. The heat radiating plate 1 is held with its side edge portion facing outward from the side surface of the frame 1.

The frame 1 contains a pair of optical path bending mirrors 12 and 13 and an objective lens 14 for guiding the light beam emitted from the light source 4 and condensing it on the signal recording surface of the magneto-optical disk. That is, the light beam emitted from the light emitting / receiving composite element 2 is deflected by 90 ° by the first optical path bending mirror 12, further deflected by 90 ° by the second optical path bending mirror 13, and
4 is incident. The objective lens 14 is moved by a biaxial actuator 15 in the optical axis direction (focus direction) of the objective lens 14 shown by an arrow F in FIG. 1 and in a direction (tracking direction) orthogonal to the optical axis shown by an arrow T in FIG. 2
It is movably supported in the axial direction.

The biaxial actuator 15 is insert-molded into the frame 1 to
, And a magnetic yoke part 17 erected integrally on the base part 16. A magnet 29 is attached to the magnetic yoke 17. A support block 19 is provided on the base 16. A lens holder 21 is attached to the support block 19 via a flexible transfer arm 20. This lens holder 21 includes an objective lens 1
4 and the drive coil 30 are attached. The objective lens 14 is supported at a position where the light beam deflected by the second bending mirror 13 is incident. The coil 30
It is located in a magnetic field formed by the magnet 29 and the magnetic yoke 17. In the two-axis actuator 15, by supplying a drive current to the coil 30, the lens holder 21 is moved in the two-axis direction with respect to the base 16, and the objective lens 14 is moved in the focus direction and the tracking direction. Operated.

The frame 1 has a pair of coaxial support holes 22 at one end. These support holes 22,
The cylindrical thrust bearings 18, 18 are held inside 22 by insert molding. The frame 1 has a support groove 23 at the other end. In the recording / reproducing apparatus having the optical pickup device, the frame 1 is provided with thrust bearings 18 and 18.
The support shaft (main shaft) 24 is inserted through the support shaft 24, and the sub shaft 25 is engaged with the support groove portion 23, whereby the support shaft (main shaft) 24 is movably supported along the support shaft 24 as shown by an arrow S in FIG. By supporting the frame 1 in this manner, the objective lens 14 is opposed to a signal recording surface of a magneto-optical disk which is supported on a spindle shaft and rotated in the recording / reproducing apparatus. The frame 1 is moved along the support shaft 24 to move in the radial direction of the magneto-optical disk supported in the recording / reproducing apparatus.

In the optical pickup device, a light beam emitted from the light source 4 is focused on a signal recording surface of a magneto-optical disk mounted on the recording / reproducing device via an objective lens 14 in the recording / reproducing device. The light beam reflected from the signal recording surface is received by the light receiving elements 5 and 6 via the objective lens 14 so that the information signal can be recorded / reproduced on / from the magneto-optical disk. The optical pickup device rotates the magneto-optical disk by a spindle motor and moves the magneto-optical disk along the support shaft 24 over the inner and outer peripheries of the magneto-optical disk. Information signals can be recorded and reproduced over the entire recording surface.

The optical pickup device is not limited to the configuration using the light emitting and receiving composite element 2 as described above. As shown in FIG. 3, a single laser diode 26 is used as a light source, and a beam splitter 27 An optical system may be configured by disposing a photodetector such as a photodiode in the frame 1. This laser diode 26
Is configured to house a laser diode chip in a metal sealed can. The laser diode 26 is provided on the heat sink 1 held in the frame 1 by insert molding.
1 is attached. In this optical pickup device, the light beam emitted from the laser diode 26 passes through the beam splitter 27, is reflected by the second bending mirror 13, and
The light is incident on the objective lens 14 supported by 5.

In this optical pickup device, as shown in FIG. 4, a balance weight 28 as a metal component may be held in the frame 1 by insert formation. The balance weight 28 prevents the entire optical pickup device from being unbalanced (for example, in a state where the position of the center of gravity of the entire optical pickup device is at the center), and the frame 1 is supported by the support shaft 2.
Also, when a moving operation is performed along the line 4 or when the objective lens 14 is moved, complicated mode resonance is prevented from occurring, and good optical characteristics are maintained.

For example, as shown in FIG. 4, when the support groove 23 is located at a position deviated from a straight line V perpendicular to the support shaft 24 passing through the center of the objective lens 14, as shown in FIG. Is further distant from the straight line V so that the center of gravity of the entire optical pickup device is located on the straight line V.

Further, the balance weight 28 and the heat radiating plate 11 can secure sufficient rigidity of the frame 1 while suppressing the overall weight of the frame 1.

[0028]

As described above, in the optical pickup device according to the present invention, the frame on which the light source and the objective lens for condensing the light beam emitted from the light source on the signal recording surface of the optical recording medium are mounted. , Made of synthetic resin material, and holds metal parts by insert molding. This metal component constitutes a heat radiating member for radiating heat generated by the light source with light emission to the outside, and an actuator for movably supporting the objective lens on the frame and moving the objective lens by electromagnetic force. Magnetic yoke,
It can function as a balance weight for adjusting the position of the center of gravity of the entire frame.

That is, according to the present invention, the installation of the magnetic yoke and the optical components is facilitated and the manufacturing is facilitated without inviting a complicated and large-sized device configuration, and the heat generated from the light source is sufficiently reduced. In addition, it is possible to provide an optical pickup device in which heat can be dissipated to the outside, and sufficient rigidity is ensured, the overall balance is improved, and resonance of a complicated mode is prevented from occurring. Things.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of an optical pickup device according to the present invention.

FIG. 2 is a longitudinal sectional view showing a configuration of the optical pickup device.

FIG. 3 is a longitudinal sectional view showing another embodiment of the configuration of the optical pickup device according to the present invention.

FIG. 4 is a plan view showing still another embodiment of the configuration of the optical pickup device according to the present invention.

FIG. 5 is a perspective view showing a configuration of a conventional optical pickup device.

[Explanation of symbols]

1 frame, 4 light sources, 11 heat sink, 14 objective lens, 15 biaxial actuator, 17 magnetic yoke, 28 balance weight

Claims (4)

[Claims] 1. A frame made of a synthetic resin material and holding a metal part by insert molding, a light source attached to the frame, and a light beam provided on the frame and emitted from the light source, An optical pickup device comprising: an objective lens for focusing light on a signal recording surface of a recording medium. 2. The heat dissipating member according to claim 1, wherein the metal component radiates heat generated by the light source with light emission to the outside.
An optical pickup device as described in the above. 3. The optical pickup device according to claim 1, wherein the metal component is a magnetic yoke that constitutes an actuator that movably supports the objective lens on the frame and moves the objective lens by electromagnetic force. 4. The optical pickup device according to claim 1, wherein the metal component is a balance weight for adjusting the position of the center of gravity of the entire frame.