JPH08194965A - Integrated optical head - Google Patents

Abstract

PURPOSE: To reduce the size and weight while ensuring high heat dissipation effect by disposing a semiconductor laser such that the irradiating direction of laser light intersects the optical axis of an objective lens perpendicularly thereby simplifying the optical path and decreasing the number of optical components, and to obtain an optical head suitable for high speed access by eliminating the translation supporting. CONSTITUTION: A semiconductor laser 32 is disposed at one end of an optical disc not corresponding to the tracking direction of an optical disc such that the irradiating direction of laser light substantially intersects the optical axis of an objective lens perpendicularly. Since the laser light emitted from the semiconductor laser 32 is introduced to an objective lens 25a through single right angle reflection, as compared with a conventional head requiring two times of right angle reflection, the number of components can be decreased in the optical system. When the end part of the optical head body 25 is fixed to one end part of a heat dissipation plate having the other end part 30 extending oppositely to the surface of the optical disc, high heat dissipation effect can be achieved. Furthermore, since the optical head body 25 is supported rotatably in the tracking direction by an optical head support 24, vibration due to translation supporting is eliminated thus realizing an optical head suitable for high speed access.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for recording and reproducing information using an optical disc as a recording medium, and more particularly to improvement of an integrated optical head device for irradiating the optical disc with laser light.

[0002]

2. Description of the Related Art As is well known, in a system for recording and reproducing information using an optical disk as a recording medium, such as a write-once type optical disk drive device, the optical disk is irradiated with laser light. Optical head device. This optical head device is arranged so as to face the signal recording surface of a rotationally driven optical disc, and records information by irradiating the optical disc with laser light or receives reflected light from the optical disc. Reading information.

Here, in recent years, a semiconductor laser for generating a laser beam, an optical system for guiding the laser beam generated from this semiconductor laser, and a laser beam guided by this optical system are focused on an optical disk. An integrated optical head device has been developed which integrates an objective lens for moving the objective lens, an actuator section for moving the objective lens in a focus direction and a tracking direction, and a photodetector for receiving reflected light from an optical disk.

FIG. 7 shows such a conventional integrated optical head device. That is, reference numeral 11 in the drawing is a frame formed in a substantially U-shape, and is arranged so that its opening side faces the signal recording surface of the optical disc (not shown). On both side surfaces 11a and 11b of the frame 11,
The magnets 12a and 12b are attached. Further, the bottom surface portion 11c of the frame 11 is provided with yokes 13a and 13b facing the magnets 12a and 12b and forming magnetic closed paths with the magnets 12a and 12b, respectively. The optical head body 14 is arranged between the yokes 13a and 13b. In this optical head body 14,
An objective lens 14a for exposing and receiving laser light to the optical disc is exposed.

The optical head main body 14 is provided with focus actuator coils 15a and 15b and tracking actuator coils 16a and 16b on both side surfaces facing the yokes 13a and 13b, respectively. These focus actuator coils 15
a, 15b and tracking actuator coil 16
a and 16b are the magnets 12a and 12b and the yoke 1, respectively.
It is interposed in the magnetic path formed by 3a and 13b.

Therefore, by energizing the focus actuator coils 15a, 15b and the tracking actuator coils 16a, 16b, the optical head main body 14 is in a direction perpendicular to the signal recording surface of the optical disk in the focus direction (indicated by an arrow in the figure). (Direction shown in AA)
Also, the optical disc can be moved in the tracking direction (direction shown by arrow BB in the figure) which is the radial direction of the optical disc.

Here, in the optical head main body 14, the joint portions 14b and 14c provided at both ends in the tracking direction (the direction indicated by the arrow BB in the figure) have a pair of elastic support columns 17a and 17a, respectively. By being attached to one side surface portion 11a of the frame 11 via the and 17b, 17b, the frame 11 is movably supported in the focus direction and the tracking direction.

FIG. 8 shows the internal structure of the optical head body 14. That is, in the optical head body 14,
A package 18 is provided alongside the objective lens 14a. The package 18 includes a semiconductor laser 19
And the photodetector 20 is thermally bonded. Then, the laser light emitted from the semiconductor laser 19 travels in the direction indicated by the arrow C in the figure, which is the focus direction,
The light is reflected by the reflecting mirror 21 at a right angle, that is, in the direction indicated by arrow D in the figure.

The laser light reflected by the reflecting mirror 21 passes through an optical component (not shown), and then the reflecting mirror 2
It is reflected by 2 at a right angle, that is, in the direction indicated by an arrow A in the figure, and is irradiated onto the optical disc through the objective lens 14a. Further, the laser light applied to the optical disc strikes the signal recording surface of the optical disc, is reflected, and is received by the photodetector 20 along a path opposite to the above.

Here, in the optical head main body 14,
The reason why the package 18 is provided side by side on the objective lens 14a will be described. That is, since the semiconductor laser 19 generates heat during use, it is known that the longer the continuous use, the higher the temperature, and the shorter the service life. Therefore, how efficiently the heat generated from the semiconductor laser 19 is released to the outside is a factor that extends the life of the semiconductor laser 19.

Therefore, it has been conventionally considered that the heat is radiated by utilizing the forced convection action of air generated when the optical disc is rotated at a high speed. In order to realize such heat dissipation means, the semiconductor laser 1
The package 18 to which 9 is attached must be set at a position facing the optical disc, and therefore the package 18 is inevitably arranged in line with the objective lens 14a.

When the optical head main body 14 performs recording or reproduction on the optical disc, the focus actuator coils 15a and 15b and the tracking actuator coils 16a and 16b are energized based on the detection result of the photodetector 20, whereby Deviation in the focus direction (direction shown by arrow AA in FIG. 7) and tracking direction (direction shown by arrow BB in FIG. 7)
Will be controlled so as to reduce the deviation.

However, in the conventional integrated optical head device configured as described above, the irradiation direction of laser light from the semiconductor laser 19 provided in the package 18 (direction shown by arrow C in FIG. 8) is set. , Objective lens 14a
Since it is parallel to the optical axis (in the direction indicated by the arrow A-C in FIG. 8) of, the optical path needs to be bent at least twice in order to guide this laser light to the objective lens 14a. However, there is a problem in that the number becomes large and the weight becomes large.

Since both ends of the optical head main body 14 in the tracking direction are supported by the frame 11 by the elastic support columns 17a and 17b, the optical head main body 14 is movably supported in the frame 11 in the tracking direction. That is, the frame 11 itself is movably supported in the tracking direction, so that the frame 11 itself is translationally supported in the tracking direction.

Therefore, when the integrated optical head device is used in a device such as a CD-ROM drive that requires high-speed access, the center of gravity of the optical head body 14 and the elastic support columns 17a and 17b are used. Due to the deviation from the support center in the tracking direction, residual vibration remains in the optical head body 14 in the frame 11 even if the movement of the frame 11 itself is stopped.

[0016]

As described above, in the conventional integrated optical head device, it is necessary to bend the optical path a plurality of times in order to guide the laser light emitted from the semiconductor laser to the objective lens. There is a problem that the number of parts is increased and the size and weight are increased. Further, since the optical head main body is translationally supported in the tracking direction, there is also a disadvantage that residual vibration remains in the internal optical head main body when the movement of the entire apparatus in the tracking direction is stopped.

The object of the present invention is to reduce the number of optical components by simplifying the optical path to achieve size and weight reduction, obtain a high heat radiation effect, and eliminate translational support, which is also suitable for high-speed access. An object is to provide an integrated optical head device.

[0018]

SUMMARY OF THE INVENTION An integrated optical head device according to the present invention comprises an objective lens arranged so that its optical axis is substantially orthogonal to the optical disc surface, and one end which does not correspond to the tracking direction of the optical disc. A semiconductor laser disposed so that the irradiation direction of the laser light is substantially orthogonal to the optical axis of the objective lens, and an optical path that reflects the laser light emitted from the semiconductor laser at a substantially right angle and guides it to the objective lens. An optical head main body including a photodetector for receiving reflected light from an optical disc through an objective lens, and a focus actuator coil and a tracking actuator coil arranged on both sides corresponding to the tracking direction of the optical disc, and the optical head The objective lens can be moved with respect to the optical disk in the focusing direction and the tracking direction, respectively. And a base portion facing the end portion of the optical head body opposite to the end portion where the semiconductor laser is arranged, and an extension portion extending elastically with respect to the base portion so as to be movable in the focus direction. An optical head support body integrally formed with a support portion that extends rotatably in the tracking direction with elastic force with respect to the extension portion and supports the optical head main body; A frame supporting a plurality of magnets for supporting the base of the optical head main body and applying a magnetic field to the focus actuator coil and the tracking actuator coil of the optical head main body, and the semiconductor laser of the optical head main body. One end is attached to the other end, and the other end is provided with a heat radiating plate extended to the vicinity of the objective lens along the optical disc surface.

[0019]

According to the above-mentioned structure, the semiconductor laser is arranged so that the irradiation direction of the laser light is substantially orthogonal to the optical axis of the objective lens. Therefore, the laser light emitted from the semiconductor laser is used for the objective lens. The number of parts of the optical path leading to the optical head can be reduced, and the size and weight of the optical head body can be reduced.

Further, since the semiconductor laser is arranged at the end of the optical head main body and the heat dissipation plate attached to this end is extended along the optical disk surface to the vicinity of the objective lens, the high speed of the optical disk is achieved. A high heat dissipation effect using forced air convection due to rotation can be obtained.

Further, since the optical head main body is constructed so as to be pivotally supported in the tracking direction by the optical head support, the optical head main body will not unnecessarily vibrate in the tracking direction due to disturbance, and high speed access is required. Will be suitable for the device.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 1, reference numeral 23 in the drawing is a frame formed in a substantially L-shape, and one side of the frame 23a is arranged so as to face a signal recording surface of an optical disc (not shown). A base portion 24a of an optical head support 24 is attached to a side surface portion 23b on the other side of the frame 23. This optical head support 24
As will be described later in detail, the optical head main body 25 is supported by the first pair of arms 24b, 24b and the second pair of arms 24c, 24c extending from the base portion 24a. An objective lens 25a for exposing and receiving laser light on the optical disk is exposed on the optical head body 25.

The optical head main body 25 is provided with a focus actuator coil 26a and a tracking actuator coil 27a on both side surfaces (only one side surface is shown in the figure) corresponding to the tracking direction of the optical disk. There is. The focus actuator coil 26a and the tracking actuator coil 27a are composed of a magnet 28a attached to a side cover 23c extending substantially at right angles from both side ends (only one side end is shown in the figure) of the bottom surface portion 23a of the frame 23. , The bottom surface portion 23 of the frame 23 so as to face the magnet 28a.
It is interposed in the magnetic closed circuit formed by the yoke 29a installed in a.

Further, one end of a heat radiating plate 30 is attached to the optical head main body 25 on the side opposite to the side of the optical head support 24 facing the base portion 24a. The other end of the heat radiating plate 30 is bent at a substantially right angle so as to cover the upper surface of the optical head body 25 in the figure, and the tip end thereof is the objective lens 25.
It reaches the vicinity of a and is used for heat dissipation by forced convection generated by rotation of the optical disk.

FIG. 2 shows the integrated optical head device shown in FIG. 1 disassembled into its constituent parts. That is,
A pair of side covers 23c and 23d, which are bent at substantially right angles so as to face each other, extend from both ends of the bottom surface 23a of the frame 23. Magnets 28a and 28b are attached to the side covers 23c and 23d, respectively. Further, the bottom surface portion 23a of the frame 23 is provided with yokes 29a and 29b facing the magnets 28a and 28b and forming magnetic closed paths with the magnets 28a and 28b, respectively. Then, the optical head body 25 is arranged between the yokes 29a and 29b.

At this time, the optical head main body 25 has focus actuator coils 26a and 26b, and a pair of tracking actuators, respectively, on both side surfaces corresponding to the tracking direction (the direction indicated by the arrow BB in the drawing). Coils 27a, 27a and 27b, 2
7b is attached. And this optical head body 25
Is supported by the frame 23 via the optical head support 24, the focus actuator coil 26
a, 26b and tracking actuator coil 27
a and 27b are magnets 28a and 28b and a yoke 2 respectively.
9a and 29b are to be interposed in the magnetic path formed by them.

The optical head main body 25 has a side opposite to the side facing the base portion 24a of the optical head support 24,
That is, the package 3 is attached to the side where the heat sink 30 is attached.
1 is detachably provided. As will be described in detail later, a semiconductor laser, a photodetector, or the like is thermally joined to the package 31. Here, the package 31 has, for example, a pair of joint holes 3 formed at both ends thereof.
The optical head main body 25 is integrated with the optical head main body 25 by fitting the 1a and 31a into the pair of joining pins 25b and 25b protruding outward from the corresponding opening end portions of the optical head main body 25. Then, one side of the heat dissipation plate 30 formed by bending a plate body made of a heat conductive material into a substantially L shape is attached to the outside of the package 31, for example, with a heat conductive adhesive or the like.

Further, on the bottom surface portion 23a of the frame 23, a pair of joints 23e, 23e are juxtaposed from the vicinity of the side surface portion 23b along the side surface portion 23b. The optical head support 24 is fixed to the frame 23 by fitting a pair of through holes 24d, 24d formed in the base portion 24a of the optical head support 24 into the pair of connectors 23e, 23e. Will be done.

Here, FIG. 3 shows the optical head support 24.
Shows a specific configuration of. That is, the base 24a
Is formed of, for example, a synthetic resin material having elasticity into a plate shape having a predetermined thickness, and a pair of joints formed on the frame 23 in the focus direction (direction shown by arrow AA in the drawing). Through hole 2 into which the children 23e, 23e are fitted
4d and 24d are formed. The first pair of arms 24b, 24b are provided at the upper end of the base 24a in the figure.
Are integrally formed. The first pair of arms 24b, 24b extend from the base portion 24a in the same direction at a predetermined first interval, and are narrowed to a second interval narrower than the first interval at the central portion, They are connected by an integrally formed connecting portion 24e. Also, these first
In the pair of arms 24b, 24b, each connecting portion with the base portion 24a and the connecting portion 24e is formed thin so as to have flexibility. Therefore, the base portion 24a and the first pair of arms 24b, 24b are rotatable around the tracking direction, that is, the direction indicated by the arrow BB. The first pair of arms 24b, 24b and the connecting portion 24e are also rotatable in the same direction.

On the other hand, at the lower end of the base portion 24a in the figure,
The second pair of arms 24c, 24c are integrally formed. These second pair of arms 24c, 24c
Is extended from the base portion 24a in the same direction at a predetermined first distance, and is narrowed to a second distance narrower than the first distance at the central portion, and then is integrally formed by a connecting portion 24f. It is connected. Further, in the second pair of arms 24c, 24c, each connecting portion with the base portion 24a and the connecting portion 24f is formed thin so as to have flexibility. For this reason, the base portion 24a and the second pair of arms 24c, 24c are in the tracking direction, that is, the arrow B.
It is rotatable about the direction indicated by -B. Also,
The second pair of arms 24c, 24c and the connecting portion 24f are also rotatable in the same direction.

In addition, substantially square pillar-shaped support portions 24g and 24h are integrally formed at the central portions of the connecting portions 24e and 24f, respectively, toward the base portion 24a. These supporting portions 24g and 24h are respectively connected to the connecting portion 2
The connecting portions with 4e and 24f are formed thin so as to have flexibility. Therefore, the support portions 24g, 24h
Is rotatable about the coupling portions 24e and 24f in the focus direction, that is, in the direction indicated by the arrow AA.

The supporting portions 24g and 24h are
As shown in FIG. 2 again, the optical head main body 25 is supported by being fitted into the fitting holes 25c formed in the upper and lower parts (only the upper part is shown in FIG. 2) of the optical head main body 25 in the figure. It is supported by the body 24. In this case, the optical head body 25 has its objective lens 25a as shown in FIG.
The portion supporting the first pair of arms 24b, 24b
Will be loosely inserted within the first interval. Therefore, while being supported by the optical head support 24, the optical head main body 25 moves in the tracking direction, that is, the direction shown by the arrow BB in FIG. 3 (strictly speaking, due to the flexibility of the support portions 24g and 24h). It is possible to rotate about the direction indicated by the arrow AA).

Further, since the optical head main body 25 is supported by the optical head support 24, the first and second pair of arms 24b, 24b and 24c, 24c constitute a link mechanism, so that the focus direction, It is movable in the direction indicated by the arrow AA in FIG.

In short, with the optical head support 24 supporting the optical head main body 25 attached to the frame 23, the optical head main body 25 is movable in the focus direction and the tracking direction. By energizing the coils 26a, 26b and the tracking actuator coils 27a, 27b, the objective lens 25a can be controlled in the focus direction and the tracking direction. In the normal state, the optical head main body 25 is stabilized at the substantially central position of the moving range by the elastic force of the arms 24b and 24c of the optical head support 24 and the support portions 24g and 24h.

Next, FIG. 4 shows a specific structure of the package 31. The package 31 is formed of a material having a high thermal conductivity, and the semiconductor laser 32 is formed in the substantially central portion thereof.
And the photodetector 33 are thermally joined. Then, as shown in FIG. 5, the laser light emitted from the semiconductor laser 32 advances in a direction parallel to the signal recording surface of the optical disc, that is, a direction indicated by an arrow D in the figure, passes through an optical component (not shown), and then is reflected. The light is reflected by the mirror 34 at a right angle, that is, in the direction indicated by the arrow A in the figure, and is irradiated onto the optical disk through the objective lens 25a. Further, the laser beam applied to the optical disc hits the signal recording surface of the optical disc and is reflected, and follows the path opposite to the above to the photodetector 33.
Is received by.

FIG. 6 shows the positional relationship between the above-mentioned integrated optical head device and the optical disk 35. That is, the optical disc 35 is mounted on a spindle 36 supported by a chassis (not shown) and rotated. The integrated optical head device has the objective lens 25a.
Is supported by a chassis so as to be movable in the radial direction of the optical disc 35 while facing the signal recording surface of the optical disc 35. At this time, one side of the heat radiating plate 30 faces the signal recording surface of the optical disc 35, and heat is radiated by forced convection generated when the optical disc 35 is rotationally driven.

Therefore, according to the configuration of the above-described embodiment, the irradiation direction of the laser light emitted from the semiconductor laser 32 (the direction indicated by the arrow D in FIG. 5) is set to the objective lens 2.
Since the laser beam emitted from the semiconductor laser 32 is reflected only once at a right angle by the reflecting mirror 34, the objective is obtained because the laser beam emitted from the semiconductor laser 32 is perpendicular to the optical axis of 5a (the direction shown by the arrow A-C in FIG. 5). Since it is guided to the lens 25a, the number of parts of the optical system that converts the optical path of the laser light is reduced, and the optical head main body 25 can be made smaller and lighter. Further, since the base portion 24a of the optical head support 24 and the heat radiating plate 30 are arranged at opposite ends of the optical head body 25, the device can be downsized also in this respect.

The package 31 itself to which the semiconductor laser 32 is attached does not face the optical disc 35, but one end of the heat sink 30 is attached to the package 31.
Since the other end of the optical disk is made to face the optical disk 35, a high heat dissipation effect using forced air convection due to the high speed rotation of the optical disk 35 can be obtained.

Further, since the optical head main body 25 is constructed so as to be pivotally supported by the frame 23 in the tracking direction, the optical head main body 25 rarely vibrates unnecessarily in the tracking direction even when a disturbance is given. Therefore, it becomes suitable for a device that requires high-speed access.

[0040]

As described above in detail, according to the present invention,
To provide an integrated optical head device capable of reducing the number of optical components by simplifying an optical path to reduce the size and weight, obtaining a high heat dissipation effect, and eliminating translational support and also suitable for high-speed access. You can

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an integrated optical head device according to the present invention.

FIG. 2 is an exploded perspective view showing a specific configuration of the same embodiment.

FIG. 3 is a perspective view showing a specific configuration of an optical head supporter in the example.

FIG. 4 is a perspective view showing a specific configuration of a package in the same embodiment.

FIG. 5 is a diagram shown for explaining an optical path of an optical head body in the embodiment.

FIG. 6 is a diagram for explaining the positional relationship between the integrated optical head device and the optical disc in the embodiment.

FIG. 7 is a perspective view showing a conventional integrated optical head device.

FIG. 8 is a diagram for explaining an optical path of an optical head main body in the conventional apparatus.

[Explanation of symbols]

11 ... Frame, 11a ... Side part, 11b ... Side part, 1
1c ... bottom part, 12a ... magnet, 12b ... magnet, 13a ...
Yoke, 13b ... Yoke, 14 ... Optical head body, 14a
... objective lens, 14b ... junction, 14c ... junction, 15
a ... Focus actuator coil, 15b ... Focus actuator coil, 16a ... Tracking actuator coil, 16b ... Tracking actuator coil, 17a ... Elastic support column, 17b ... Elastic support column, 18 ... Package, 19 ... Semiconductor laser, 20 ... Photodetector , 21 ... Reflector, 22 ... Reflector, 23 ...
Frame, 23a ... Bottom part, 23b ... Side part, 23c ...
Side cover, 23d ... Side cover, 23e ... Junction, 24 ... Optical head support, 24a ... Base, 24b ... Arm, 24c ... Arm, 24d ... Through hole, 24e ... Connecting part, 24f ... Connecting part, 24g ... Support Part, 24h ... Support part, 25 ... Optical head main body, 25a ... Objective lens, 25b
... Joining pin, 25c ... Fitting hole, 26a ... Focus actuator coil, 26b ... Focus actuator coil, 27a ... Tracking actuator coil,
27b ... Tracking actuator coil, 28a ...
Magnet, 28b ... Magnet, 29a ... Yoke, 29b ... Yoke, 30 ... Heat sink, 31 ... Package, 31a ... Bonding hole, 32 ... Semiconductor laser, 33 ... Photodetector, 3
4 ... Reflecting mirror, 35 ... Optical disk, 36 ... Spindle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideaki Karahara 3-3-9 Shimbashi, Minato-ku, Tokyo Toshiba Abu E. Co., Ltd.

Claims (2)

[Claims] 1. An objective lens arranged such that its optical axis is substantially orthogonal to the optical disc surface, and one end portion of the optical disc, which does not correspond to the tracking direction, has a laser beam irradiating direction of the objective lens. A semiconductor laser arranged so as to be substantially orthogonal to the axis, an optical path that reflects the laser light emitted from the semiconductor laser at a substantially right angle and guides it to the objective lens, and a light reflected from the optical disc through the objective lens. An optical head main body including a light detection unit that receives light through the optical disc, and a focus actuator coil and a tracking actuator coil that are arranged on both sides corresponding to the tracking direction of the optical disc; In contrast, it is supported so that it can move in the focus direction and the tracking direction respectively. A base portion facing an end portion of the optical head body opposite to the end portion on which the semiconductor laser is arranged, an extension portion that is elastically movable with respect to the base portion and is movably extended in the focus direction, and the extension portion. An optical head support body that is integrally formed with a support portion that is rotatably extended in the tracking direction with elastic force with respect to the projecting portion and supports the optical head main body; A frame that supports the base portion, and that supports a plurality of magnets that apply a magnetic field to the focus actuator coil and the tracking actuator coil of the optical head body supported by the optical head body; One end is attached to the end where the semiconductor laser is arranged, and the other end is extended to the vicinity of the objective lens along the optical disk surface. Integrated optical head apparatus characterized by comprising; and a plate. 2. The extension part of the optical head support is a pair of first and second arms arranged on the base along the focus direction, and the support is the first pair of arms. Is formed at a substantially central portion of a first coupling portion that couples the distal end portions of the arms to each other, and at a substantially central portion of a second coupling portion that couples the distal end portions of the second pair of arms, respectively. The integrated optical head device according to claim 1, wherein the integrated optical head device is formed.