JP2001266377A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical pickup device which surely prevents an air-cored coil and inner yokes from bumping against each other by regulating the moving range of a lens holder surely and which is provided with a stopper free from blocking normal moving of the lens holder. SOLUTION: In the optical pickup device 1, stoppers 35 and 36 project toward the air-cored parts 710 and 720 of driving coils for focusing 71 and 72 (air-cored coils) from the lens holder 3. Thus, when the holder 3 moves too much, the inner yokes 43 and 44 arranged in the parts 710 and 720 never collides with the coils 71 and 72 in spite of bumping against the stoppers 35 and 36. Consequently, the coils 71 and 72 are never cut off by colliding with the inner yokes 43 and 44.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact disc (CD) and a digital versatile disc (DVD).
The present invention relates to an optical pickup device used for reproducing an optical recording disk such as an optical disk. More specifically, the present invention relates to a structure for restricting a moving range of a lens holder holding an objective lens in an optical pickup device.

[0002]

2. Description of the Related Art In an optical pickup device used for reproducing an optical recording disk such as a CD or a DVD, a lens holder holding an objective lens is driven in a tracking direction and a focusing direction to reproduce a signal from the optical recording disk. Such an optical pickup device has a structure in which a lens holder is supported by a wire, and a structure in which a lens holder is supported by a support shaft fitted in a shaft hole formed in the lens holder. The latter is disclosed, for example, in Japanese Patent Application Laid-Open No. Hei 10-31555.

[0003] This type of optical pickup device is called a shaft sliding and rotating type. For example, as shown in FIG. 1, an objective lens 31, a lens holder 3 for holding the objective lens 31, a lens holder 3 A support shaft 4 that supports the movable member 3 in a focusing direction and a tracking direction.
And a magnetic drive circuit for driving the lens holder 3 in the focusing direction and the tracking direction. The magnetic drive circuit includes tracking drive coils 73 and 74 and focusing drive coils 71 and 72 fixed to the lens holder 3, and magnets 75 and 76 fixed to the outer yoke 42 of the cup-shaped yoke 4. . In the optical pickup device 1 shown in FIG. 1, an air-core coil that opens toward the axial direction of the support shaft 45 is used as the focusing driving coils 71 and 72, and the air-core coils 710 and 720 have Is a cup-shaped yoke 4
Inner yokes 43 and 44 are located upright.

[0004] The optical pickup device 1 configured as described above.
Then, the objective lens 31 is driven in the tracking direction by rotating the lens holder 3 around the support shaft 45 using the magnetic force acting between the tracking drive coils 73 and 74 and the magnets 75 and 76. In addition, the objective lens 31 is driven in the focusing direction by moving the lens holder 3 in the axial direction of the support shaft 45 by using the magnetic force acting between the focusing drive coils 71 and 72 and the magnets 75 and 76.

[0005]

However, in the optical pickup device 1 shown in FIG. 1, the air-core portion 71 of the air-core coil used as the focusing drive coils 71 and 72.
Since the inner yokes 43 and 44 are located inside the lens holders 0 and 720, when the lens holder 3 rotates too much around the support shaft 45, the air-core coils (the focusing drive coils 71 and 7) are rotated.
In 2), there is a possibility that the inner yokes 43 and 44 abut and the coil is disconnected.

Therefore, as shown in FIG. 4, for example, ribs 39 extending radially from the center of the lens holder 3 are provided.
A recess 398 is formed by the rib 391 and the body 399 between the first and the 392, and a structure is employed in which the stopper 49 protrudes from the bottom wall 41 (see FIG. 1) of the cup-shaped yoke 4 into the recess 398. . According to this stopper mechanism, when the lens holder 3 rotates too much, the stopper 49
Abuts against the inner wall of the concave portion 398, whereby the rotation range of the lens holder 3 can be defined.

However, in the configuration in which the stopper 49 protruding from the cup-shaped yoke 4 is arranged between the ribs 391 and 392, when the stopper 49 is inclined or the position of the stopper 49 is shifted, Since the rotation range cannot be regulated accurately, the inner yokes 43, 44 reliably prevent the inner yokes 43, 44 from abutting against the air core coils (focusing drive coils 71, 72) when the lens holder 3 rotates around the support shaft 45. It is not possible. Also, if burrs or return are generated when the stopper 49 is processed, the burrs or the like will stick into the inner wall of the concave portion 398 of the lens holder 3 and the lens holder 3 will not move. There is a problem that the lens holder 3 is stuck between the parts and the like and cannot move.

Therefore, an object of the present invention is to reliably restrict the moving range of the lens holder so that the air core coil and the yoke located inside the air core coil can be reliably prevented from abutting, and An object of the present invention is to provide an optical pickup device provided with a stopper that does not hinder normal movement of a lens holder.

Another object of the present invention is to provide an optical pickup device which can securely fix an air-core coil to a predetermined position with respect to a lens holder using the stopper.

[0010]

According to the present invention, there is provided an objective lens for converging light emitted from a light source on an optical recording medium, a lens holder for holding the objective lens, and a lens. In an optical pickup device having a support member that supports the holder in a state movable in the focusing direction and the tracking direction, and a magnetic drive circuit that drives the lens holder in the focusing direction and the tracking direction, the lens holder includes:
An air core coil constituting the magnetic drive circuit is fixed, an inner yoke projects from the support member toward the inside of an air core portion of the air core coil, and the lens holder has an air core of the air core coil. A stopper that defines the range of movement of the lens holder by projecting into the section and abutting on the inner yoke when the lens holder moves is formed.

In the present invention, since the stopper projects from the lens holder toward the air core of the air core coil,
When the lens holder moves too much, the inner yoke arranged in the air core portion of the air core coil hits the stopper,
It does not hit the air core coil. Therefore, the movement range of the lens holder can be restricted by the stopper, and the air-core coil does not break due to collision with the inner yoke. Further, in the present invention, since the stopper is formed not on the lens holder but on the lens holder itself to which the air-core coil is fixed, the positional relationship between the air-core coil and the stopper is high. Accuracy is obtained. For this reason, the air core coil is reliably protected from collision with the inner yoke by the stopper. Therefore, the problem that the inner yoke collides with the air-core coil and the coil is disconnected can be reliably avoided. Furthermore, since the stopper abuts not on the lens holder side having a complicated structure but on the inner yoke having a simple structure, the stopper is caught by the inner yoke and the lens holder does not move. Does not occur. Furthermore, since the inner yoke is made of metal, there is no problem that the stopper pierces the inner yoke and the lens holder does not move.

In the present invention, the support member has, for example, a support shaft that fits in a shaft hole formed in the lens holder, and the lens holder moves in the axial direction of the support shaft so that the object is moved. While the lens moves in the focusing direction, the objective lens moves in the tracking direction by rotating around the axis of the support shaft, and the air core coil has the air core portion in the axial direction of the support shaft. It is a focusing drive coil that opens. In such a configuration, the stopper regulates a range (rotation range) when the lens holder moves in the tracking direction.

In the present invention, the air core coil is fixed to the lens holder as a first air core coil and a second air core coil, and each air core of the first and second air core coils is fixed. Generally, the inner yoke is arranged as a first inner yoke and a second inner yoke on each of the cores. In such a case, the stopper includes a first stopper that regulates a movement range of the lens holder in one of the tracking directions when the stopper comes into contact with the first inner yoke, and the second inner yoke. A second range that regulates the movement range of the lens holder in the other direction in the tracking direction when
Is preferably formed on the lens holder as a stopper. With this configuration, the movement range can be restricted in any of the tracking directions of the lens holder. Therefore, since the collision between the air-core coil and the inner yoke can be reliably prevented, disconnection of the coil due to such a collision can be reliably prevented.

In the present invention, it is preferable that the stopper projects at a lower end position of a fixing region of the air core coil with respect to the lens holder. With this configuration, when the air-core coil is fixed to the lens holder,
After positioning the air-core coil with reference to the stopper, the air-core coil can be fixed. Therefore, the air core coil can be accurately fixed to a predetermined position. Further, since the air-core coil is supported from below by the stopper, it is possible to prevent the air-core coil from dropping from the lens holder.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Since the basic configuration of the optical pickup device described below is common to the conventional configuration,
Portions having common functions are denoted by the same reference numerals.

FIG. 1 is a schematic configuration diagram of an optical pickup device to which the present invention is applied. FIG. 2 is a perspective view of the lens holder used in the optical pickup device to which the present invention is applied, as viewed obliquely from below. 3 (A), (B),
(C) is a plan view showing the positional relationship between the air-core coil, the stopper, and the inner yoke in the optical pickup device using the lens holder shown in FIG. 2, and the stopper moves in one direction in the tracking direction of the lens holder. And a plan view showing a state where the stopper regulates a movement range of the lens holder in the other direction in the tracking direction.

(Overall Configuration) As shown in FIG. 1, an optical pickup device 1 performs information recording and information reproduction on an optical recording disk 6 (optical recording medium) such as a CD or a DVD, and a metal such as aluminum. A shaft sliding / rotating type supporting an objective lens 31 for focusing light emitted from a light source (not shown) on an optical recording disk 6 so as to be movable in a focusing direction and rotatable in a tracking direction on a frame 5 composed of Are configured. Guide holes 5 made of round holes are provided at both ends of the frame 5.
1 and a guide portion 52 protruding in a U-shape, and along the guide shaft (not shown) passed through each of the guide hole 51 and the guide portion 52, the optical pickup device 1 It can move in the radial direction, which is the radial direction of the optical recording disk. In frame 5,
A hole 501 for arranging a light source and various optical elements, a hole 502 for arranging the actuator 2, and the like are formed.

The actuator 2 comprises a lens holder 3 for holding an objective lens 31 and a cup-shaped yoke 4. The cup-shaped yoke 4 includes a support shaft 45 that fits into the shaft hole 33 formed in the lens holder 3, and is a holding member that supports the lens holder 3 movably in the tracking direction and the focusing direction.

The lens holder 3 has a shape in which the upper surface is closed by a top plate 32 of a body portion 34, and an objective lens 31 is mounted on the top plate 32, and a shaft hole 33 is opened at the center thereof. The shaft hole 33 is formed of, for example, a cylindrical bearing.

In the lens holder 3, a pair of tracking drive coils 73 and 74 are provided on the outer peripheral surface of the body 34.
A pair of focusing drive coils 71 and 72 (first and second focusing drive coils) are attached. The tracking drive coils 73 and 74 have a flat shape having a substantially rectangular vertical cross section, and one end surface thereof is adhered to the outer peripheral surface of the lens holder 3.

Focusing drive coils 71 and 72
The air core 7 extends in the axial direction of the support shaft 45 of the cup-shaped yoke 4.
Air core coils 10 and 720 are open, and their outer peripheral surfaces are bonded to the outer peripheral surface of the lens holder 3.

The cup-shaped yoke 4 has a circular bottom wall 41,
A cylindrical outer yoke 42 raised from the outer peripheral edge of the bottom wall 41
And a pair of inner yokes 43 and 44 (first and second inner yokes) formed by cutting and raising a part of the bottom wall 41, and a support shaft 45 that stands vertically from the center of the bottom wall 41. ing. The inner yokes 43 and 44 can be attached as separate components without directly cutting and raising a part of the bottom wall 41.

The magnetic drive circuit of the actuator 2 is formed by inserting the shaft hole 33 of the lens holder 3 into the support shaft 45 of the cup-shaped yoke 4. This magnetic drive circuit
A pair of tracking drive coils 73 and 74 attached to the lens holder 3, a pair of focusing drive coils 71 and 72, and the inner peripheral surface of the outer yoke 42 of the cup-shaped yoke 4 facing these drive coils. It is composed of a pair of magnets 75 and 76 attached,
Air core 71 of focusing drive coils 71 and 72
At 0 and 720, the inner yokes 43 and 44 are located.

The magnets 75 and 76 are polarized in the circumferential direction around a portion where the tracking drive coils 73 and 74 face each other, and a portion where the tracking drive coils 73 and 74 face each other is a tracking drive coil. Magnet parts 751 and 761 are provided. Magnet 7
In the parts 5 and 76, the opposing portions of the focusing drive coils 71 and 72 are magnetized in a single pole, and these are the focusing drive magnet parts 752 and 762. Incidentally, the magnets 75 and 76 can be formed even if they are divided into two by magnetized polarization lines.

The actuator 2 configured as above is
An objective lens that converges the light emitted from the light source to the optical recording disk 6 by controlling the power supply to the focusing drive coils 71 and 72 and the tracking drive coils 73 and 74 via the flexible printed circuit board 77. 31 (lens holder 3) and holder support shaft 4
5 along the vertical direction (focusing direction) or around the support shaft 45 (tracking direction).

(Characteristic part of lens holder 4) In the optical pickup device 1 thus configured, in the present embodiment,
As shown in FIGS. 2 and 3A, on the lower surface side of the lens holder 3 (the side facing the bottom wall 41 of the cup-shaped yoke 4), the air core portions 7 of the focusing drive coils 71 and 72 are disposed.
Flat stoppers 35, 36 toward each of 10, 720
(The first and second stoppers) slightly overhang each. In the present embodiment, the stoppers 35 and 36
The lens holder 3 is formed at the same time when the resin is formed.

Here, when the rotation direction of the lens holder 3 is viewed from above, an arrow CW is shown in clockwise and counterclockwise directions, respectively.
Expressed by an arrow CCW, the stopper 35 projects from the clockwise CW side in the tracking direction toward the counterclockwise CCW with respect to the air core 710 of the focusing drive coil 71. However, the stopper 35
Only slightly protrudes with respect to the air core 710 of the focusing driving coil 71, so that the lens holder 3 is in the normal angle range even if the inner yoke 43 is disposed inside the air core 710. The stopper 35 does not come into contact with the inner yoke 43 as long as it rotates inside.

On the other hand, the stopper 36 projects from the counterclockwise CCW side in the tracking direction toward the clockwise CW with respect to the air core 720 of the focusing drive coil 72. However, the stopper 36 is also
Since the focusing drive coil 72 only slightly protrudes from the air core portion 720, the air core portion 72
Even if the inner yoke 44 is arranged inside the zero, the stopper 36 does not contact the inner yoke 44 as long as the lens holder 3 rotates within a normal angle range.

The stopper 3 in the lens holder 3
5 and 36 are formed at the lower end positions in the fixing area of the focusing driving coils 71 and 72,
The upper end surfaces of the stoppers 35 and 36 receive the lower end surfaces 711 and 721 of the focusing drive coils 71 and 72, respectively.

As shown in FIG. 3A, in the optical pickup device 1 of the present embodiment, the actuator 2 is
When the lens 1 (lens holder 3) is not driven in the tracking direction, the inner yokes 43 and 44 are located at substantially the center positions of the air-core portions 710 and 720 of the focusing drive coils 71 and 72 in the tracking direction. Also, within the range where the tracking correction is performed normally, the lens holder 3
Even if is rotated around the support shaft 45, the stoppers 35 and 36 do not abut against the inner yokes 43 and 44.

On the other hand, as shown in FIG.
When the lens holder 3 has rotated too much clockwise CW, the inner yokes 43, 44 move relatively in the counterclockwise CCW direction in the air core portions 710, 720 of the focusing drive coils 71, 72, but the focusing is performed. The lens holder 3 in the air core portion 710 of the driving coil 71 for
The stopper 35 protrudes in the clockwise direction CW. Therefore, before the inner yokes 43 and 44 collide with the focusing driving coils 71 and 72, the inner yokes 43 abut against the stopper 35, so that the inner yokes 43 and 44 do not collide with the focusing driving coils 71 and 72. Absent.

Contrary to this operation, as shown in FIG. 3C, when the lens holder 3 has rotated too much counterclockwise CCW, the focusing drive coil 7
The inner yoke 4 at the air core portions 710, 720
3 and 44 move relative to each other in the clockwise direction CW, but in the air core 720 of the focusing drive coil 72,
A stopper 36 protrudes from the lens holder 3 in the counterclockwise direction CCW. For this reason, the inner yokes 43, 44
Since the inner yoke 44 collides with the stopper 36 before colliding with the focusing drive coils 71 and 72, the inner yokes 43 and 44
There is no collision with 72.

(Effect of this Embodiment) As described above, in the optical pickup device 1 of this embodiment, the stopper is provided from the lens holder 3 toward the air core portions 710 and 720 of the focusing drive coils 71 and 72 (air core coils). When the lens holder 3 has moved too much, the inner yokes 43, 4 arranged in the air cores 710, 720, since the lenses 35, 36 protrude.
4 strikes the stoppers 35 and 36, but does not collide with the focusing drive coils 71 and 72. Therefore, since the movement range of the lens holder 3 can be regulated by the stoppers 35 and 36, the focusing driving coils 71 and 72 are not disconnected by collision with the inner yokes 43 and 44.

In this embodiment, the stoppers 35 and 36 are formed on the lens holder 3 itself to which the focusing driving coils 71 and 72 are fixed, instead of forming the stopper separately from the lens holder 3. Therefore, the focusing drive coils 71 and 72 and the stoppers 35 and 36
High accuracy is obtained in the positional relationship with. For this reason, even when the lens holder 3 moves too much in the tracking direction,
The focusing drive coils 71 and 72 are
5 and 36 reliably protect against collision with the inner yokes 43 and 44. Therefore, the focusing driving coil 7
1, 72 does not break.

Further, since the stoppers 43 and 44 abut against the lens holder 3 having a complicated structure and the inner yokes 43 and 44 having a simple structure, the stoppers 35 and 36 are not in contact with each other. The problem that the lens holder 3 does not move between the yokes 43 and 44 does not occur. Furthermore, since the inner yokes 43 and 44 are made of metal, there is no problem that the stoppers 35 and 36 pierce the inner yokes 43 and 44 and the lens holder 3 does not move.

Further, in the present embodiment, of the stoppers 35 and 36, the stopper 35 serves as a first stopper and moves the lens holder 3 in one direction (clockwise CW) in the tracking direction when hitting the inner yoke 43. The range is regulated, and the stopper 36 is
6, since the rotation range of the lens holder 3 is restricted in the other direction (counterclockwise CCW) in the tracking direction when the lens holder 3 collides with the yoke 44, the movement range of the lens holder 3 in any of the tracking directions is limited. Can be regulated. Therefore, the collision between the focusing drive coils 71 and 72 and the inner yokes 43 and 44 can be reliably prevented, and the disconnection of the coil due to such a collision can be reliably prevented. In addition, since high precision is obtained in the positional relationship between the focusing driving coils 71 and 72 and the stoppers 35 and 36, the stroke of the clockwise CW and the counterclockwise CCW with respect to the lens holder 3,
Alternatively, it is easy to set the moving distance of the objective lens 31 to the inner peripheral side and the outer peripheral side with respect to the optical recording disk 6 equally.

Since the stoppers 35, 36 protrude at the lower end positions of the fixing regions of the focusing drive coils 71, 72 with respect to the lens holder 3, the stoppers 35, 36 are attached to the lens holder 3 in the assembly process of the optical pickup device 1 (actuator 2). On the other hand, the focusing drive coil 71,
When the fixing 72 is fixed, the vertical position of the focusing driving coils 71 and 72 (position in the axial direction of the support shaft 45) is adjusted with reference to the stoppers 35 and 36, and then the focusing driving coils 71 and 72 are bonded and fixed. be able to. Accordingly, the focusing driving coils 71, 7
2 can be accurately fixed to the predetermined position. The focusing drive coils 71 and 72 are provided with stoppers 35 and 36.
After the focusing drive coils 71 and 72 are fixed to the lens holder 3,
The dropping of the focusing drive coils 71 and 72 from the lens holder 3 can be prevented by the stoppers 35 and 36.

(Other Embodiments) In the above embodiment, each of the focusing drive coils 71 and 72 has one
Although the two stoppers 35 and 36 are formed and each restricts the movement range in one direction, the inner yokes 43 and 44 are formed by forming two stoppers on each of the focusing drive coils 71 and 72. May surely be prevented from colliding with the focusing drive coils 71, 72.

In the above embodiment, the present invention is applied to an optical pickup device of a shaft sliding rotation type. For example, in an optical pickup device of a type in which a lens holder is supported by a wire, the inside of an air-core coil is provided. When an inner yoke is disposed in the air core coil, a stopper may be formed on the air core of the air core coil.

[0040]

As described above, in the optical pickup device of the present invention, the stopper projects from the lens holder toward the air core of the air core coil. The inner yoke arranged in the air core portion of the core coil abuts against the stopper, but does not abut the air core coil. Therefore, the movement range of the lens holder can be restricted by the stopper, and the air-core coil does not break due to collision with the inner yoke. Further, in the present invention, since the stopper is formed on the lens holder itself to which the air-core coil is fixed, high positional accuracy between the air-core coil and the stopper can be obtained. For this reason, the air core coil is reliably protected from collision with the inner yoke by the stopper. Therefore, the problem that the inner yoke collides with the air-core coil and the coil is disconnected can be reliably avoided. Furthermore, since the stopper abuts not on the lens holder side having a complicated structure but on the inner yoke having a simple structure, the stopper is caught by the inner yoke and the lens holder does not move. Does not occur.
Furthermore, since the inner yoke is made of metal, there is no problem that the stopper pierces the inner yoke and the lens holder does not move.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an optical pickup device to which the present invention is applied.

FIG. 2 is a perspective view of a lens holder used in an optical pickup device to which the present invention is applied, as viewed obliquely from below.

FIGS. 3A, 3B, and 3C respectively show an optical pickup device using the lens holder shown in FIG.
A plan view showing a positional relationship between the air core coil, the stopper, and the inner yoke, a plan view showing a state in which the stopper regulates a movement range in one direction in the tracking direction of the lens holder, and a stopper in the tracking direction of the lens holder. It is a top view showing the state where the movement range in the other direction is regulated.

FIG. 4 is a perspective view showing a positional relationship between a stopper and a lens holder when a lens holder used in a conventional optical pickup device is viewed obliquely from below.

[Explanation of symbols]

Reference Signs List 1 optical pickup device 2 actuator 3 lens holder 4 cup-shaped yoke 5 frame 6 optical recording disk (optical recording medium) 31 objective lens 32 top plate 33 shaft hole 35, 36 stopper 42 outer yokes 43, 44 inner yoke 45 support shaft 71, 72 Focusing drive coil (air core coil) 710, 720 Air core part of air core coil 73, 74 Tracking drive coil 75, 76 Magnet

Claims (4)

[Claims] An objective lens for converging light emitted from a light source to an optical recording medium, a lens holder for holding the objective lens, and the lens holder supported so as to be movable in a focusing direction and a tracking direction. In an optical pickup device having a support member and a magnetic drive circuit for driving the lens holder in a focusing direction and a tracking direction, an air core coil constituting the magnetic drive circuit is fixed to the lens holder, An inner yoke protrudes toward the inside of the air core portion of the air core coil, and the lens holder has an inner yoke that extends over the air core portion of the air core coil when the lens holder moves. A stopper that defines the range of movement of the lens holder by abutting An optical pickup device characterized by the above-mentioned. 2. The support member according to claim 1, wherein the support member has a support shaft that fits into a shaft hole formed in the lens holder, and the lens holder moves in an axial direction of the support shaft. While the objective lens moves in the focusing direction, the objective lens moves in the tracking direction by rotating around the axis of the support shaft, and the air core coil includes the air core portion in the axial direction of the support shaft. An optical pickup device characterized in that it is a focusing drive coil having an opening. 3. The air core coil according to claim 2,
The first and second air-core coils are fixed to the lens holder as a first air-core coil and a second air-core coil.
The inner yoke is disposed as a first inner yoke and a second inner yoke at each of the air core portions of the air core coil, and the stopper is disposed in the tracking direction when the stopper comes into contact with the first inner yoke. A first stopper that regulates a movement range of the lens holder in one direction; and a second stopper that regulates a movement range of the lens holder in the other direction in the tracking direction when the lens holder collides with the second inner yoke. An optical pickup device, wherein the stopper is formed on the lens holder. 4. The method according to claim 1, wherein
The optical pickup device, wherein the stopper projects at a lower end position of a fixing region of the air core coil with respect to the lens holder.