JPH0512687A - Light pickup device - Google Patents

Abstract

PURPOSE:To reduce the size of a light pickup and to prevent the occurrence of a resonance by crossing the line, which connects a guide member that holds a carriage, and the line, which connects a driving point that drives the carriage, inside the carriage. CONSTITUTION:Looking from the X direction, F-F is the line which connects a driving point F of a first carriage coil 22a and a driving point F of a second carriage coil 22b. Furthermore, S-S is the line which connects a center S of a standard guide rail 30 and a center S of a driven guide rail 31. Here, the intersection point of F-F and S-S is constructed to go through the centroid of a light pickup 39a. By constructing this manner, no rotational moment is generated and the occurrence of a resonance is prevented when the light pickup 39a moves in the X direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device used in an optical information recording / reproducing device for recording / reproducing optical information on / from an optical information recording medium such as an optical disk, and more particularly to an optical information recording / reproducing device. The present invention relates to an optical pickup device configured so as to be suitable for downsizing of the device.

[0002]

2. Description of the Related Art An apparatus which records / reproduces information on / from one optical disc by using a plurality of optical pickups is disclosed in, for example, Japanese Patent Laid-Open No. 62-4064.
Some are disclosed in Japanese Patent No. FIG. 7 is a diagram showing the configuration of the optical pickup device disclosed in Japanese Patent Laid-Open No. 62-40646. This apparatus arranges a plurality of optical pickups 101a to 101d, each of which is configured to be independently accessible, in a radial pattern with respect to a rotation center 102 of an optical disc, and the optical pickups are randomly placed at desired positions. It enables high-speed access to record / reproduce information.

An information recording medium such as an optical disk is usually housed in a cartridge in order to protect the surface of the medium or to facilitate handling. Figure 8
FIG. 3 is a plan view showing the structure of a cartridge that is currently generally used. As shown in FIG. 8, the cartridge 1
An opening 105 is provided on one surface of 04, and a light beam is applied to the information recording surface of the information recording medium through the opening 105 to record / reproduce information.

However, in the optical pickup device shown in FIG. 7, since a plurality of optical pickups are radially arranged, the optical pickup device is housed inside a general cartridge having only one opening as shown in FIG. It cannot be applied to the recorded information recording medium. In addition, since four optical pickups are arranged in a radial pattern, there is a disadvantage that the volume occupied by the optical pickups in the optical information recording / reproducing apparatus becomes large and the size of the entire apparatus cannot be reduced.

In order to access, for example, a plurality of optical pickups to an information recording medium housed in a general cartridge as shown in FIG. 8 and to downsize the apparatus,
It is necessary to arrange a plurality of optical pickups side by side in the track direction (tangential direction), and it is also necessary to reduce the dimension of each optical pickup in the tangential direction and to reduce the distance between the objective lenses. Also in the case of an information recording / reproducing apparatus using one optical pickup, in order to downsize the apparatus, it is necessary to reduce the size of the optical pickup, for example, in the tangential direction, and to reduce the space occupied by the optical pickup.

An apparatus for reducing the size of the optical pickup in the tangential direction is disclosed in, for example, Japanese Patent Laid-Open No.
There is one described in Japanese Patent Publication No. 3-50924. FIG. 9 is a perspective view showing the structure of this optical pickup device. In this apparatus, guide rails 113a and 113b for guiding the carriage 111 on which the objective lens 110 is mounted in a direction (tracking direction) orthogonal to the track,
Since the magnetic circuit for driving the carriage 111 on which the objective lens is mounted and the magnetic circuit for driving the carriage 111 are vertically arranged in the focus direction, the size in the tangential direction is small.

However, the support center of the carriage 111, that is, the center line connecting the two guide rails 113a and 113b, and the drive point for driving the carriage in the tracking direction are vertically displaced from each other in the tracking direction. However, there is a problem that a moment is generated when the carriage moves in the tracking direction, and resonance easily occurs.

The present invention has been made in order to solve the above-mentioned problems, and the size of the optical pickup device, for example, in the tangential direction is reduced to miniaturize the information recording / reproducing device, and the carriage is An object of the present invention is to provide an optical pickup device in which resonance hardly occurs when moving in the tracking direction.

[0009]

In order to solve the above-mentioned problems, an optical pickup device of the present invention has an optical element for irradiating a light spot on an information recording surface of an optical information recording medium, and an optical element for mounting the optical element. A carriage for placing the carriage, a support means for movably supporting the carriage in a first direction orthogonal to a direction of an information recording track formed on the optical information recording medium, and at least the optical element for recording the information. An optical element driving means for driving in a second direction perpendicular to the plane,
In an optical pickup device including a drive unit that integrally moves the carriage in the first direction, the support unit has a guide member extending in the first direction, and the carriage of the guide member The line connecting the support points and the line connecting the drive points that drive the carriage by the drive means intersect inside the carriage.

[0010]

1 is a plan view showing the structure of an optical pickup device according to a first embodiment of the present invention, and FIG. 2 is a partially exploded perspective view thereof.
FIG. 3 is a side view of the device shown in FIG. 1 viewed from the tracking direction. In the attached drawings, the X direction indicates the tracking direction, the Y direction indicates the tangential direction, and the Z direction indicates the focusing direction. Also,
In this embodiment, as applicable to an information recording medium housed in a commonly used cartridge,
A device provided with a plurality of optical pickups will be described.

As shown in FIG. 1, two optical pickups 39a and 39b are arranged side by side in the Y direction, and these optical pickups 39a and 39b are the X of the optical disc 1.
It is configured to be movable in any direction. Reference numeral 3 indicates a spindle motor that rotates the optical disc 1. A fixed optical system 41 is provided next to each of the optical pickups 39a and 39b.
a, 41b are arranged, the light beams emitted from these fixed optical systems are introduced into the optical pickups 39a, 39b, and the objective lenses 10, 1 provided in the optical pickups are provided.
Information is recorded / reproduced by irradiating the track 2 of the optical disc 1 through 0. Optical pickup 3
9a and 39b are formed in the same manner, and the following description will be given for only one optical pickup.

As shown in FIG. 2, the objective lens 1
0 is held by the lens holder 11, and focus coils 12 wound in a square shape are fixed to both side surfaces of the lens holder 11 in the X direction. Convex portions 11a are formed on both side surfaces of the lens holder 11 in the Y direction.
Two springs 13 are attached to the upper and lower side surfaces of the
The lens holder 11 is supported so as to be movable in the Z direction.
A total of four springs 13 extend in parallel to each other on the side portion of the lens holder 11, and the other end of the spring 13 is fixed to the holding member 14. As the spring 13, for example, a thin plate made of beryllium copper having a thickness of about 0.1 mm and covered with butyl rubber for damping is used.

The carriage 18 has a lens holder holding portion 1.
8a and a carriage coil holding portion 18b,
As shown in FIG. 3, these holding portions are arranged so as to be oblique when viewed from the X direction. Convex portions 18c and 18d are formed on the upper side surface of the lens holder holding portion 18a, and the lens holder 11 is arranged in the middle of these convex portions. The above-mentioned holding member 14 has one convex portion 18
It is fixed to the outer surface of c. X of the lens holder 11
Magnets 15 and 15 and yokes 16 and 16 are arranged in the gaps formed between the side surfaces in the direction and the convex portions 18c and 18d, respectively. Yoke 16,1 made of iron plate
The outer side surfaces of 6 are fixed to the inner side surfaces of the convex portions 18c and 18d, respectively, and the outer side surfaces of the magnets 15 and 15 are fixed to the inner side surfaces of the yokes 16 and 16, respectively. The inner surfaces of the magnets 15 and 15 are magnetized in two poles in the Z direction so that the different poles face each other, and the magnetized surfaces of these two poles have the first pole wound in a square shape. The second pole is located on the upper side of the focus coil 12 so as to face the lower side.

Lens holder holding portion 18 of carriage 18
An opening 18e is provided at the center of a, and the mirror 17 is fixed in the opening 18e. Further, the through hole 18 penetrating from one side surface to the opening 18e.
f is formed to extend in the X direction, and the fixed optical system 41
The light beam from a (FIG. 1) is guided to the mirror 17 through the through hole 18f, reflected there, and guided to the objective lens 10. Further, bearing fixing portions 18g are provided on both sides of the lens holder holding portion 18a of the carriage 18 in the X direction.

As shown in FIG. 3, between the carriages 18 of the two optical pickups 39a and 39b,
The reference guide rail 30 is provided so as to extend in the X direction, and subordinate guide rails 31 are provided on both sides of the reference guide rail 30 so as to diagonally face each other. Two bearings 19a are press-fitted and fixed to each of the bearing fixing portions 18g provided on the lens holder holding portion 18a of the carriage 18 so as to sandwich the reference guide rail 30. On the other hand, on the bottom surface of the carriage coil holding portion 18b of the carriage 18, one bearing 19b is fixed on the lower side, and a bearing 19c for preload is fixed on the upper side by a screw 21 via a spring 20 made of stainless steel. .. These four bearings 19a are brought into contact with the reference guide rail 30, and the bearings 19b, 19
By bringing c into contact with the dependent guide rail 31, the carriage 18 is supported so as to be movable in the X direction along the guide rails 30 and 31.

Two carriage coils 22a and 22b are attached to the carriage coil holding portion 18b of the carriage 18. The carriage coil 22a contacts the upper surface of the carriage coil holding portion 18b and the Y direction of the lens holder holding portion 18a so that the carriage coil 22a contacts the inner side surface of the carriage coil holding portion 18b in the Y direction and the bottom surface of the lens holder holding portion 18a. It is attached so as to contact the outer surface of the. These coils are arranged so as to intersect the arrangement of the reference guide rail 30 and the subordinate guide rail 31 when viewed in the X direction.

Yokes 34a and 37 are arranged in the carriage coils 22a and 22b, respectively.
A magnet 35 is arranged at a position facing the carriage coil 22b arranged on the upper side, and a magnetic gap 29a which cooperates with one side of the carriage coil 22b is formed between the yoke 37 and the magnet 35. The magnet 35 is fixed to the inside of the long side of the U-shaped yoke 36, and the magnet 35-yoke 37-yoke 36-
A magnetic circuit including the magnet 35 is formed.

Similarly, a yoke 34a is arranged inside the carriage coil 22a arranged on the lower side, and a magnet 32 is arranged at a position facing the carriage coil 22a.
To form a magnetic gap 29b that cooperates with the carriage coil 22a. A yoke 34b is arranged symmetrically with the yoke 34a with the magnet 32 interposed therebetween. The magnet 32 is fixed to the yoke 33 adhered to the ends of the yokes 34a and 34b.
-Yoke 34b-Yoke 33-Yoke 34a-Magnet 32 constitutes a magnetic circuit. The thickness of the magnet 32 and the magnet 35 is equal to the magnetic gap 2
The magnetic flux density of 9a and the magnetic flux density of the magnetic gap 29b are determined to be the same.

In this embodiment, two optical pickups 3
The magnets 9a and 39b are the same and are provided to face each other, and form a magnetic circuit that drives the reference guide rail 30 and the inner carriage coil 22a.
Are commonly used. As shown in FIG. 3, in the optical pickup device, when viewed from the X direction, a line FF connecting the drive point F of the first carriage coil 22a and the drive point F of the second carriage coil 22b and the reference point The intersection S-S connecting the center S of the guide rail 30 and the center S of the driven guide rail 31 is configured to pass through the center of gravity of the optical pickup 39a. Therefore, the optical pickup 3
When 9a moves in the X direction, no rotation moment is generated and resonance is hard to occur. Of course, it is most preferable that the intersection passes through the center of gravity of the optical pickup 39a, but even if it is slightly deviated, the rotation moment is small and resonance is hard to occur as compared with the conventional case.

The guide rails 30 and 31 for supporting the carriage 18 are XY including the tangential direction.
Since it is not arranged on a plane, the distance in this direction can be reduced, and the size of the optical pickup can be reduced.

The optical pickups 39a, 39b are mounted on a base (not shown), and the spindle motor 3 for rotating the disk 1, fixed optical systems 41a, 41b, guide rails 30, 31 are mounted on the base. , York 3
3, 34a, 34b, 36 and 37 are fixed.
The two fixed optical systems 41a and 41b having exactly the same configuration are fixed in opposite directions.

Next, the operation of this embodiment will be described with reference to FIGS. The fixed optical systems 41a and 41b are the laser 4
2. Photodetector 43 and beam splitter 44
And a light beam emitted from the laser 42 is reflected by the galvanometer mirror 40, and the optical pickup 39a,
It is incident on the mirror 17 installed in the opening 18e of the carriage 18 of 39b. The reflected light from the mirror 17 is guided to the objective lens 10 and is condensed to project a light spot on the disc 1. Then, the light beam reflected by the disk 1 again passes through the objective lens 10 and the mirror 17,
The light is reflected by the galvanometer mirror 40, the optical path is bent by the beam splitter 44 installed in the fixed optical system 41, and the light enters the photodetector 43.

As shown in FIG. 3, in this embodiment, the movable parts of the optical pickups 39a and 39b including the objective lens 10, the reference guide rail 30, and the bearing 19a are provided in the opening provided in the cartridge 4 of the optical disk 1. Located within 5.

When a current flows through the focus coil 12 in this state, the focus coil 12 is electromagnetically affected by the magnetic field generated by the two magnetic poles magnetized by the magnet 15.
Force is generated in the focus direction (Z direction). As a result, the spring 13 is deformed and the objective lens holder 11 moves in the focus direction. On the other hand, the carriage coil 22a
Alternatively, when a current flows in 22b, a force in the X direction is generated in the carriage coil by the electromagnetic action with the magnetic field generated by the magnet 32 or 35, and the entire optical pickup is moved in the X direction along the guide rails 30 and 31. Moving. As described above, the two objective lenses 10 and 10 are contained in the opening 5 of the cartridge 4, and are applied to recording / reproducing on / from the information recording medium contained in the cartridge which has been generally used in the past. Can facilitate even more random and fast access. Also,
Since the guide rail 30 and the magnet 32 are shared by the two pickups, these objective lenses 10,
The distance between 10 is reduced, and the optical pickup device can be downsized.

Further, since the guide member for guiding the carriage in the tracking direction, the driving means for driving the objective lens in the focusing direction, and / or the driving means for driving the carriage in the tracking direction are shared by a plurality of optical pickups. The number of parts can be reduced, and the manufacturing cost can be reduced.

All of the carriages for mounting the objective lenses of a plurality of optical pickups are of the same shape, and are mounted 180 degrees different from each other.
Manufacturing costs can be reduced. Further, since the carriages have the same shape, the reference guide member can be shared, and the positional accuracy of the carriages can be increased.

FIGS. 4 and 5 are a partially exploded perspective view and a side view, respectively, of the apparatus of the second embodiment of the present invention, and FIG. 6 shows the state of magnetic force lines acting on the focus coil of the second embodiment. It is a figure.

In this embodiment, an L-shaped bent focus coil 70 is attached to the bottom surface of the lens holder 50. In FIG. 5, an arm 72a is attached to the upper surface of the carriage 72, and an opening 50b provided in the lens holder 50 (FIG.
The mirror 17 inserted in the reference (see) is fixed. The mirror 17 guides the light beam from the fixed optical system to the objective lens 10 through a hole 50a formed in the side surface of the lens holder 50. The opposite end of the arm 72a is fixed to the holding member 14 that fixes the support spring 13 that movably supports the lens holder 50 in the focus direction. Rectangular coils 53 surrounding a later-described yoke 74 are attached to both sides of the carriage 72 in the X direction, and bearing holding portions 72b and 72b are provided near the objective lenses. Then, a spool-shaped reference bearing 73a is press-fitted and fixed to these holding portions so as to be oblique to the disc 1. A spring 71 is fixed to the rear side of the fixing member 14, and a preload bearing 73b is press-fitted and fixed to the tip of the spring 71 so as to face the reference bearing 73a. The spring 71 is located in a magnetic gap between an inner yoke 74 and a magnet 76, which will be described later.

The fixed portion is formed such that the long sides of the yoke 74 and the L-shaped yoke 75 extend in the X direction, and the pair of corner portions of the inner yoke 74 facing each other are A cutout portion of approximately 90 ° is formed. Guide rails 30 and 31 are positioned in the notch, and these guide rails 30 and 31 are fixed to a base (not shown). The circumference of the inner yoke 74 is covered with a short ring 74a made of a copper pipe,
The inductance of the carriage coil 53 that surrounds this is reduced to improve the responsiveness. A magnet 76 is fixed to the inner side surface of the outer yoke 75, and a magnet 77 is arranged in the center of the inner yokes 74, 74. In addition, these magnets
The same poles are arranged so as to face each other.

The two bearings 73a come into contact with the guide rail 30 and the bearings 73b come into contact with the guide rail 31, so that the movable portion including the objective lens and the like is supported by the guide rail. Although not shown, as in the first embodiment, the optical pickup 39a is located at the intersection of the straight line connecting the drive points of the carriage coil 53 and the straight line connecting the support points of the guide rails 30 and 31 for supporting the carriage. The center of gravity of is set to be located. As a result, when the optical pickup 39a moves in the X direction, no rotational moment is generated, and resonance hardly occurs.

The direction of the magnetic force line acting on the focus coil 70 is, as shown in FIG.
The portions 70a and 70b parallel to the direction are opposite to each other. Therefore, 70a and 70b of the focus coil 70
Both of the forces generated in the part (1) act in the same direction in the Z direction. Thus, by adjusting the direction and magnitude of the current flowing through the focus coil 70, focusing control of the objective lens is performed. When an electric current flows through the carriage coil 53, a force in the X direction is generated on the carriage coil 53 by the electromagnetic action with the magnetic fields generated by the magnets 76, 77, and the carriage 72 moves the guide rails 30, 31.
Move along. Since the magnet 77 arranged in the center of the fixed portion is shared by the focus coil 70 and the carriage coil 53, the optical pickup device can be downsized in the Y direction.

Further, in the second embodiment, since the focus coil is bent in an L shape to increase the utilization rate, the efficiency is improved. Further, since the preload spring 71 is located in the magnetic gap, the optical pickup device can be further downsized.

In the above-mentioned embodiment of the present invention, a plurality of optical pickups are used, but it goes without saying that the optical information recording / reproducing apparatus using one optical pickup may be used. In addition, the position where the guide rail is arranged, the position of the coil that drives the movable portion, and the like can be variously changed.

[0034]

According to the optical pickup device of the present invention,
Since the line that connects the guide member that supports the carriage and the line that connects the drive point that drives the carriage are arranged so as to intersect inside the carriage, the size of the optical pickup can be reduced. Further, by making the intersecting point coincide with the center of gravity of the optical pickup, it is possible to suppress the moment generated when the optical pickup is driven in the direction orthogonal to the track of the optical recording medium, and it is difficult for resonance to occur.

Further, even when a plurality of optical pickups are arranged in the track direction, since they are small in size, they can fit in the opening of a general cartridge. Therefore, it can be directly applied to the recording / reproducing of information on the information recording medium housed in the commonly used cartridge without preparing a special cartridge.

[Brief description of drawings]

FIG. 1 is a plan view showing a first embodiment of an optical pickup device according to the present invention.

FIG. 2 is a partially exploded perspective view of the optical pickup device shown in FIG.

FIG. 3 is a side view of the optical pickup device shown in FIG.

FIG. 4 is a partially exploded perspective view showing a second embodiment of the optical pickup device according to the present invention.

5 is a side view of the optical pickup device shown in FIG.

6 is a diagram showing a state of magnetic force lines acting on a focus coil in the optical pickup device shown in FIG.

FIG. 7 is a plan view showing a conventional optical pickup device.

FIG. 8 is a plan view of a cartridge that stores an optical disc.

FIG. 9 is a perspective view showing another conventional optical pickup device.

[Explanation of Codes] 1 ... Optical disc, 2 ... Track, 3 ... Spindle motor, 4 ... Cartridge, 5 ... Cartridge opening, 1
0 ... Objective lens, 11, 50 ... Lens holder, 12, 5
1, 70 ... Focus coil, 13 ... Support spring, 14 ...
Holding member, 15, 32, 35, 56, 57, 58, 7
6, 77 ... Magnet, 17 ... Mirror 18, 52, 72
... Carriage, 19a, 53a, 73a ... Bearing,
19c, 53b, 73b ... Preload bearing, 20, 71
... Springs, 22, 53 ... Carriage coil.

Claims (1)

Claim: What is claimed is: 1. An optical element for irradiating a light spot on an information recording surface of an optical information recording medium, a carriage for mounting the optical element, and a carriage for mounting the carriage on the optical information recording medium. Support means for movably supporting in a first direction orthogonal to the direction of the information recording track formed on the optical disk, and optical element driving means for driving the optical element in at least a second direction perpendicular to the information recording surface. And a drive unit that integrally moves the carriage in the first direction, wherein the support unit has a guide member extending in the first direction. A line connecting the supporting points of the carriage and a line connecting the driving points for driving the carriage by the driving means intersect inside the carriage. Up device.