JPH10283647A - Objective lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an objective lens driving device having structure in which a magnetic plate for restoring a lens holder to a neutral position with respect to holder supporting members is simply attached. SOLUTION: A magnetic plate 20 as the neutral position holding means of a lens holder 3 is attached to the lens holder 3 of an objective lens driving device 1. The magnetic plate 20 is provided with first and second magnetic pieces 21a, 21b opposed to face respective focusing magnets 13a, 13b at its both endes and is provided with a connecting part 23 in between these pieces. Since the magnetic pieces 21a, 21b are magnetically attracted to the magnetic neutral position of the focusing magnets 11a, 11b the lens holder 3 can be restored to the neutral position. Since two magnetic pieces 21a, 21b can be arranged to the lens holder 3 only by attaching one sheet of the magnetic plate 20, the number of parts is reduced as compared with the case plural magnetic pieces are attached one by one like in the conventional practice and the attaching of the magnetic pieces is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device for an optical pickup used for reproducing an optical recording medium such as a CD. More particularly, the present invention relates to a structure of a magnetic piece for holding a lens holder holding an objective lens at a neutral position predetermined magnetically.

[0002]

2. Description of the Related Art As an objective lens driving device of an optical pickup used for reproducing an optical recording medium such as a CD, a lens holder holding an objective lens and a lens holder supported in a movable state in a tracking direction and a focusing direction are supported. A known type includes a holder support member and a support shaft, a tracking magnetic drive circuit for moving the lens holder in the tracking direction, and a focusing magnetic drive circuit for moving the lens holder in the focusing direction. ing.

Further, as a neutral position holding means for holding the lens holder at a predetermined neutral position with respect to the holder supporting member by using a magnetic drive circuit, a magnetic member is provided by facing a tracking magnet or a focusing magnet. A device in which a piece is fixed to a lens holder with an adhesive is known.

[0004]

However, the objective lens driving device having such a configuration has the following problems to be solved. First, the operation of fixing a plurality of magnetic pieces to the lens holder to compose the neutral position holding means for magnetically returning the lens holder to the neutral position is complicated and troublesome. Further, if the magnetic piece is simply fixed to the lens holder with an adhesive, the magnetic piece cannot be accurately positioned. If the mounting position of the magnetic piece is shifted, the drive sensitivity of the lens holder in the focusing direction and the tracking direction varies.

Second, when driving coils are mounted at diametrically opposed positions on the outer peripheral surface of the lens holder, it may be difficult to secure a routing path for supplying power to them.

An object of the present invention is to propose an objective lens driving device capable of accurately and easily mounting a magnetic piece for returning a lens holder to a neutral position at a target mounting position of the lens holder. . Another object of the present invention is to propose an objective lens driving device having a structure in which electric wiring for supplying power to a driving coil can be easily performed by using a magnetic piece having conductivity.

[0007]

In order to solve the above problems, the present invention utilizes a magnetic drive circuit for moving a lens holder holding an objective lens in a tracking direction and a focusing direction, and uses the magnetic drive circuit. And a neutral position holding means for generating a magnetic attraction force for holding the lens holder at a predetermined neutral position, wherein the first and second neutral position holding means are fixed to the lens holder. 2 and a connecting portion made of a magnetic material for connecting the first and second magnetic pieces to each other.

Therefore, in the present invention, if the first and second magnetic pieces connected by the connecting portion are prepared in advance,
The number of parts to be attached to the lens holder can be reduced. Also,
The attachment is easier than in the case where a plurality of magnetic pieces are attached one by one. Further, since the connecting portion made of the magnetic material forms a part of the magnetic path of the magnetic drive circuit for driving the lens holder, the magnetic flux generated by the magnet of the magnetic drive circuit can be effectively used.

Further, if the first and second magnetic pieces and the connecting portion have conductivity, these portions can be used as a part of a power supply path to the magnetic drive circuit. For this reason, since the first and second magnetic pieces and the connecting portion replace the lead wires, the power supply path of the drive coil can be simplified, and the design around the power supply of the drive coil can be simplified.

[0010] Further, the first and second magnetic pieces connected by the connecting portion can be formed as an integral body having both ends of the magnetic plate bent. As a method of attaching the magnetic plate configured as described above to the lens holder, when the lens holder is a resin molded product, the magnetic plate can be fixed to the lens holder by insert molding. By doing so, the work of separately attaching the magnetic piece can be omitted. Further, the positioning accuracy of the magnetic plate is higher than in the case where the magnetic plate is fixed with an adhesive, and variations in the driving sensitivity of focusing and tracking of the lens holder can be suppressed.

Instead of insert molding, a slit may be formed in the lens holder, and the magnetic plate may be inserted and fixed in the slit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An objective lens driving device according to the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1A is a plan view showing a schematic configuration of an objective lens driving device according to Embodiment 1 of the present invention, and FIG. 1B is a plan view of FIG. It is sectional drawing which shows the part cut | disconnected by the AA. As shown in these figures, the objective lens driving device 1 of the present example includes an objective lens 2
, A support shaft 6 inserted into a shaft hole 4 formed in the lens holder 3 to slidably support the lens holder 3, and a cup-shaped holder support to which the support shaft 6 is attached. It has a member 7. The holder support member 7 is fixedly disposed, and the lens holder 3 is moved in the tracking direction and the focusing direction by a tracking magnetic drive circuit and a focusing magnetic drive circuit formed between the lens holder 3 and the holder support member 7.

The tracking magnetic drive circuit includes a pair of tracking drive coils 12a and 12b mounted at diametrically opposed positions on the outer peripheral surface 5 of the lens holder 3.
And a pair of tracking magnets 10a and 10b attached to the inner peripheral surface 8 of the holder support member 7 at positions facing the respective tracking drive coils 12a and 12b. The tracking magnets 10a and 10b are polarized and magnetized in the circumferential direction around the axis L. When an electric current is applied to the tracking drive coils 12a and 12b, the lens holder 3 slightly rotates around the axis L, and The tracking of the lens 2 is performed.

Further, the focusing magnetic drive circuit comprises:
A pair of focusing drive coils 13a, 13b mounted at diametrically opposed positions on the outer peripheral surface 5 of the lens holder 5 at positions displaced in the circumferential direction around the axis L from the tracking drive coils 12a, 12b; It is constituted by a pair of focusing magnets 11a and 11b mounted on the inner peripheral surface 8 of the member 7 at positions facing the respective focusing drive coils 13a and 13b. The focusing magnets 11a and 11b are unipolarly magnetized or polarized in the direction of the axis L. When a current is applied to the focusing drive coils 13a and 13b,
The lens holder 3 moves in the direction of the axis L, and the objective lens 2
Focusing.

The lens holder 3 of the objective lens driving device 1 of the present embodiment has a neutral position holding means for holding the lens holder 3 at a predetermined neutral position (the state shown in FIGS. 1A and 1B). A magnetic plate 20 is attached.

FIGS. 2A to 2C are perspective views for explaining the structure of the magnetic plate 20. FIG. First, FIG.
As shown in (b), the magnetic plate 20 of the present example is composed of first and second facing magnets 11a and 11b.
Magnetic pieces 21a and 21b, and first and second magnetic pieces 2
There is provided a connecting portion 23 made of a magnetic member connecting the 1a and 21b. The first and second magnetic pieces 21a and 21b are formed in a small rectangular shape that is in close contact with the outer peripheral surface 5 of the lens holder 3, and the connecting portion 23 is in close contact with the upper surface 5 of the lens holder 3 and is the first and second magnetic pieces. The outer peripheral edges of 21a and 21b are connected to each other. In addition, the lens holder 3 is connected to the connecting portion 23.
An escape portion 24 such as a hole is formed so as not to block the shaft hole 4 formed in the hole.

As shown in FIG. 2C, the first and second
The focusing driving coils 13a and 13b are mounted on the magnetic pieces 21a and 21b. Therefore, when the lens holder 3 is held at the neutral position, the first and second magnetic pieces 21a and 21b face the focusing magnets 11a and 11b. That is, the first and second magnetic pieces 21a and 21b are
Since the lens holder 3 is magnetically attracted to the magnetic center positions of the tracking drive coils 12a and 12b,
If no current is flowing through b and the focusing drive coils 13a and 13b, they are held at the neutral positions shown in FIGS. 1 (a) and 1 (b).

As described above, in the objective lens driving device of this embodiment, the first and second magnetic pieces 21a and 21b are
Since the magnetic plate 20 integrated by 3 is used,
By fixing only one magnetic plate 20, the first and second magnetic pieces 21a, 21b can be attached. Therefore, the number of parts to be attached to the lens holder 3 can be reduced, and
The number of assembling steps can be reduced as compared with the conventional case where the magnetic pieces are attached one by one.

FIG. 3A shows a focusing magnet 11.
FIGS. 3A and 3B are schematic diagrams showing the state of the magnetic flux of the focusing magnet 11a when a and 11b are polarized in the direction of the axis L. FIG. 3B shows the focusing magnets 11a and 11b.
Focusing magnet 1 when b is monopolar magnetized
It is a schematic diagram which shows the mode of the magnetic flux of 1a. As shown in these figures, the magnetic flux 31 generated by the focusing magnets 11a and 11b (only the side of the focusing magnet 11a is shown in the drawings) is applied to the first and second magnetic pieces of the magnetic plate 20. Not only 21a and 21b but also the connection part 23 passes. For this reason, the efficiency of the magnetic drive circuit can be increased as compared with the case where the magnetic piece 91 is attached but the connecting portion 23 is not provided as in the conventional objective lens driving device shown in FIG.

As shown in FIGS. 5A and 5B, the magnetic plate 20 has first and second magnetic pieces 21a and 21b.
(Only the first magnetic piece 21a side is shown in the figure.) A bent claw 25 may be formed at the tip end 29 on the lens holder 3 side. In this case, FIG.
As shown in (d), the claw 2 is attached to the outer peripheral surface 5 of the lens holder 3.
A notch 9 into which 5 fits is formed. When formed in this manner, as shown in FIGS. 5C and 5D, the claw 25 of the magnetic plate 20 can be attached so as to fit into the notch 9, so that the positioning of the magnetic plate 20 is easy. become.

Further, the shape of the first and second magnetic pieces 21a and 21b of the magnetic plate 20 is not limited to a simple rectangle, but may be, for example, as shown in FIG. In the magnetic plate 20 shown in FIG.
Two protrusions 26 are formed at the tip 29 of the magnetic pieces 21a and 21b. In the magnetic plate 20 shown in FIG. 6B, the tips 29 of the first and second magnetic pieces 21a and 21b are provided.
One groove 27 is cut from the vicinity of the connecting portion 23 to
The first and second magnetic pieces 21a and 21b have two legs. In the magnetic plate 20 shown in FIG. 6C, the tips 29 of the first and second magnetic pieces 21a and 21b are provided.
Only thin is formed. Further, in the magnetic plate 20 shown in FIG. 6D, the first and second magnetic pieces 21 are provided.
a, 21b from the tip 29 of the connecting portion 23
Of the magnetic pieces 21a and 21b. Thus, the first and second magnetic pieces 21a,
By changing the shape or thickness of 21b, the magnetic attractive force for returning the lens holder 3 to the neutral position can be changed, and the driving sensitivity for focusing and tracking can be changed.

In the objective lens driving device 1 of the present embodiment,
Although the relief portion 24 is formed in the connecting portion 23 of the magnetic plate 20 so as not to contact the sliding shaft 6, the relief portion 24 may not be formed unless the shaft-sliding type objective lens driving device 1 is used. .

Further, the objective lens driving device 1 of this embodiment uses the magnetic plate 20 in which the first and second magnetic pieces 21a and 21b and the connecting portion 23 are integrated, but the connecting portion 23 is made of a magnetic material. If formed, the connecting portion 23 may be separate from the first and second magnetic pieces 21a and 21b.

Furthermore, the objective lens driving device 1 of the present embodiment
In the embodiment, the first and second magnetic pieces 21a and 21b face the focusing magnets 11a and 11b, but may be arranged so as to face the tracking magnets 10a and 10b.

(Embodiment 2) FIGS. 7 (a) and 7 (b)
FIG. 9 is a perspective view illustrating a lens holder of the objective lens driving device according to the second embodiment of the present invention. The basic configuration of the objective lens driving device of the present example is the same as that of the objective lens driving device 1 described in Embodiment 1 except that the magnetic plate 20 is disposed on the tracking side. The same reference numerals are given and the description is omitted.

As shown in FIG. 7A, a pair of slits 50 into which the magnetic plate 20 can be inserted are formed in the lens holder 3 of the objective lens driving device 1 of this embodiment. The pair of slits 50 are provided at positions sandwiching the shaft hole 4 so that the tracking drive coils 12 a and 12
The lens holder 3 is cut vertically downward from the upper surface 14 of the lens holder 3 so that the portion to which b is attached is cut. The vicinity of the shaft hole 4 of the slit 50 is the shaft hole 4.
The curved portion 51 is formed so as to avoid this.

The objective lens driving device 1 according to the present embodiment includes a pair of magnetic plates 2 inserted and fixed in a pair of slits 50.
0 is provided. The magnetic plate 20 is arranged vertically so that it can be inserted into the slit 50. In the connecting portion 23, a relief portion 24 curved along the curved portion 51 of the slit 50 is formed.

As shown in FIG. 7B, when the magnetic plate 20 is fitted into the slit 50, the connecting portion 23 is fitted into the slit 50 and is hidden inside the lens holder 3, and the first and second magnetic pieces are provided. 21 a and 21 b are in close contact with the outer peripheral surface 5 of the lens holder 3. Further, since two magnetic plates 20 are attached side by side, two first magnetic pieces 21a are arranged in a portion where one tracking drive coil 12a is arranged, and the other tracking drive coil 12b (not shown). The two second magnetic pieces 21b are arranged at the portion where the parentheses are arranged.

In the objective lens driving device 1 using the lens holder 3 configured as described above, the first and second magnetic pieces 21a and 21b face the tracking magnets 10a and 10b attached to the holder supporting member 7. I do. Therefore,
Since the tracking magnets 10a and 10b magnetically attract the first and second magnetic pieces 21a and 21b to their magnetic center positions, a current flows through the tracking drive coils 12a and 12b and the focusing drive coils 13a and 13b. When there is no lens holder 3, the lens holder 3 can be held at a neutral position with respect to the holder supporting member 7.

In this embodiment, the first and second magnetic pieces 2
Since 1a and 21b are connected by the connecting portion 23, the connecting portion 23 can be fitted into the slit 50 formed in the lens holder 3. Therefore, the first and second magnetic pieces 21a and 21b can be easily fixed to the lens holder 3. In addition, the magnetic plate 20 is inserted into the slit 5
Since it is fixed at 0, positioning can be performed with higher precision than when it is fixed with an adhesive or the like. Therefore, the lens holder 3
Of the focusing and tracking drive sensitivities can be suppressed.

The first and second magnetic pieces 21a, 21a
When the objective lens driving device is configured such that 1b faces the tracking magnet 10, as shown in FIG. 8, the tracking magnets 10a and 10b (only the side of the tracking magnet 10a is shown in the figure). The generated magnetic flux 52 is applied to the first and second magnetic pieces 21 of the magnetic plate 20.
It passes through not only a and 21b but also the connection part 23. For this reason,
As compared with the conventional objective lens driving device shown in FIG. 9, the efficiency of the magnetic driving circuit can be increased as compared with the case where the magnetic piece 91 is merely attached and the connecting portion 23 is not provided.

(Embodiment 3) FIG. 10A is a perspective view showing a lens holder of an objective lens driving device according to Embodiment 3 of the present invention. Note that the objective lens driving device of the present example has the same basic configuration as the objective lens driving device 1 described in the first embodiment, and thus common portions are denoted by the same reference numerals and description thereof is omitted. I do.

As shown in FIG. 10A, the lens holder 3 of the objective lens driving device of this embodiment is a resin molded product, and is insert-molded so that the magnetic plate 20 is embedded in the lens holder 3. Magnetic plate 20 used in this case
The connecting portion 2 of the magnetic plate 20 as shown in FIG.
3 is provided with a positioning hole 28 for insert molding. Further, as shown in FIG.
The connecting portion 23 is embedded in the lens holder 3 and the lens holder 3 is formed so that the first and second magnetic pieces 21 a and 21 b are exposed from the outer peripheral surface 5 of the lens holder 3.

As described above, by connecting the first magnetic piece 21a and the second magnetic piece 21b with the connecting portion 23, the first magnetic piece 21a and the second magnetic piece 21b can be fixed by insert molding. When the lens holder 3 and the magnetic plate 20 are integrated by insert molding, the operation of attaching the magnetic plate 20 can be omitted, and the number of assembly steps can be reduced. Further, since the positioning accuracy of the magnetic plate 20 is higher than in the case where the magnetic plate 20 is fixed with an adhesive, it is possible to suppress variations in the driving sensitivity of focusing and tracking of the lens holder 3.

As shown in FIG. 11A, two magnetic plates 20 may be arranged side by side and insert-molded, and two magnetic pieces may be arranged at a portion where one drive coil is mounted. Also in this case, as shown in FIG. 11B, a positioning hole 28 for insert molding is formed in the connecting portion 23 of the two magnetic plates 20. If the connecting portion 23 does not interfere with the shaft hole 4 formed in the lens holder 3, it is not necessary to form the escape portion 24 in the connecting portion 23.

(Embodiment 4) FIG. 12 is a perspective view showing a lens holder 3 of an objective lens driving device according to Embodiment 4 of the present invention. It should be noted that the objective lens driving device of this example uses the magnetic plate 2 for both focusing and tracking.
Since the basic configuration is the same as that of the objective lens driving device 1 described in Embodiment 1 except that 0 is arranged, common portions are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 12, the lens holder 3 of the objective lens driving device 1 of the present embodiment has a first magnetic plate 20a and a second magnetic plate 20b. First magnetic plate 20a
Is a first arranged at a portion to which the focusing drive coils 13a and 13b (only the side of the focusing drive coil 13a is shown in the figure) are attached.
And second magnetic pieces 21a and 21b, and first and second magnetic pieces 21a and 21b.
Of the magnetic pieces 21a and 21b. Therefore, the first and second magnetic pieces 21a, 21b of the first magnetic plate 20a are connected to the focusing magnets 11a,
Confronts 11b. The second magnetic plate 20b includes first and second magnetic members disposed at portions where the tracking drive coils 12a and 12b (only the side of the tracking drive coil 12a is shown in the figure) are attached. A piece 21a, 21b and a connecting portion 23 connecting the first and second magnetic pieces 21a, 21b are provided. Therefore, the first and second magnetic pieces 2 of the second magnetic plate 20b
1a and 21b face the tracking magnets 10a and 10b.

The connecting portion 23 of the first magnetic plate 20a and the connecting portion 23 of the second magnetic plate 20b intersect on the upper surface 14 of the lens holder 3. However, as shown in FIG. 13A, the connecting portion 23 of the first magnetic plate 20a is formed in a planar shape along the upper surface 14 of the lens holder 3, and
As shown in (b), the connecting portion 23 of the second magnetic plate 20b
Is provided with a step 30 that is recessed downward in a portion that intersects with the connecting portion 23 of the first magnetic plate 20a, so that the connecting portions 23 do not contact each other. Also in this example,
First and second magnetic pieces 2 for holding the lens holder 3 at a predetermined neutral position facing the tracking magnets 10a and 10b and the focusing magnets 11a and 11b.
Since 1a and 21b are connected by the connecting portion, they can be easily attached as compared with the case where magnetic pieces are attached one by one.

In this embodiment, the first and second magnetic plates 20
a and 20b have conductivity, and the first magnetic plate 20a
Has a pair of focusing drive coils 13a, 13
The terminals of the pair of tracking drive coils 12a and 12b are electrically connected to the second magnetic plate 20b. Therefore, the first magnetic plate 20a is composed of a pair of focusing driving coils 13a, 1a.
3b, and the second magnetic plate 20b is connected to a pair of tracking drive coils 12b.
It is used as a power supply path connecting between a and 12b.

FIG. 14 is a schematic diagram showing a power supply path of the tracking drive coil 12 and the focusing drive coil 13 of the objective lens drive device of this embodiment. As shown in this figure, one of the focusing drive coils 13
The minus terminal 36 of the focusing driving coil 13a is arranged near the center, and a minus terminal 37 of one focusing driving coil 13a is connected thereto. Also, the other focusing drive coil 13
A plus terminal 32 of the focusing driving coil 13b is arranged near b, and a plus terminal 33 of the other focusing driving coil 13b is connected thereto. One terminal 38 on the plus side of one focusing drive coil 13a and the other focusing drive coil 1
The terminal 35 on the minus side of 3b is connected to the first magnetic plate 20a.

Also, one tracking drive coil 1
A minus terminal 42 of the tracking drive coil 12a is arranged near 2a, and a negative terminal 43 of one of the tracking drive coils 12a is connected thereto. A plus terminal 39 of the tracking drive coil 12b is provided near the other tracking drive coil 12b.
Is connected to the terminal 40 on the plus side of the other tracking drive coil 12b. Terminal 44 on the plus side of one of the tracking drive coils 12a
The other end 41 of the tracking drive coil 12b is connected to the second magnetic plate 20b.

In this embodiment, the driving coil 1 for focusing is used.
Since the minus terminal 36 and the plus terminal 32 of 3a and 13b are near the focusing drive coils 13a and 13b, the focusing drive coil 13 connected thereto is connected to the minus terminal 36 and the plus terminal 32.
The terminals 37 and 33 of a and 13b need only be pulled out slightly from the focusing drive coils 13a and 13b. The first and second magnetic pieces 2 of the first magnetic plate 20a are located at the same positions as the focusing drive coils 13a and 13b.
1a, 21b are arranged, and the terminals 38 of the focusing drive coils 13a, 13b connected thereto,
Reference numeral 35 does not need to route the inside and outside of the lens holder 3.

The tracking drive coil 12a,
Since the minus terminal 42 and the plus terminal 39 of 12b are also near the tracking drive coils 12a and 12b, the tracking drive coils 12a and 12b connected thereto are connected.
The terminals 43 and 40 of the tracking drive coil 12a,
It is only necessary to draw a little from 12b. Further, since the first and second magnetic pieces 21a and 21b of the second magnetic plate 20b are arranged at the same position as the tracking drive coils 12a and 12b, the tracking drive coils 12a and 12b connected to the first and second magnetic pieces 21a and 21b The terminals 44 and 41 do not have to route around the inside of the lens holder 3.

As described above, the objective lens driving device 1 of this embodiment
A pair of drive coils disposed at diametrically opposed positions of the lens holder 3 with the first and second magnetic plates 20;
Since it can be electrically connected by a and 20b, it is not necessary to route lead wires and the like inside and outside the lens holder 3.
Therefore, it is not necessary to consider the lead wire routing structure, and the power supply paths of the tracking drive coils 12a and 12b and the focusing drive coils 13a and 13b can be simplified. This simplifies the design around the power supply of the drive coil.

FIGS. 15A to 15E are perspective views showing a method of electrically connecting the terminal of the drive coil to the magnetic plate 20. FIG. As shown in FIG. 15A, the terminal 35 of the drive coil can be wound around the connecting portion 23 of the magnetic plate 20. Also, as shown in FIG. 15B, grooves 45 are formed in the first and second magnetic pieces 21a and 21b of the magnetic plate 20,
The terminal 35 of the drive coil may be wound there. Further, as shown in FIGS. 15C and 15D, the connecting portion 23 of the magnetic plate 20 and the first and second magnetic pieces 21 are formed.
It is also possible to form a protrusion 46 on a and 21b, and wind the terminal 35 of the drive coil there. Projection 4 on magnetic plate 20
In the case where the drive coil 6 is formed, as shown in FIG. 15E, the terminal 35 of the drive coil is sandwiched between the protrusion 46 and the first and second magnetic pieces 21a and 21b or the connecting portion 23. It is also possible to employ a fusing method in which a current is applied while pressurizing a portion sandwiching the terminal 35 and the terminal 35 of the drive coil is fused.

The drive coil terminal 35 is connected to the magnetic plate 20.
When the fusing method is adopted for attaching the drive coil, the step of attaching the terminal 35 of the drive coil to the magnetic plate 20 and the step of forming the drive coil can be performed consistently.

FIG. 16 is a view for explaining a method of consistently performing the step of attaching the drive coil terminal 35 to the magnetic plate 20 and the step of forming the drive coil.
(A) is a front view of a portion forming a drive coil, and FIG.
FIG. 17B is a cross-sectional view illustrating a portion cut along a line DD in FIG. Further, FIG.
FIG. 1A is a front view showing a state in which a drive coil is formed, and FIG.
FIG. 6D is a cross-sectional view illustrating a portion taken along line EE in FIG. 16C.

As shown in FIGS. 16A and 16B, a projection 46 is formed on the connecting portion 23 of the magnetic plate 20 attached to the lens holder 3. In addition, the first and second magnetic pieces 2
A groove 27 is cut from the tip of 1a, 21b (only the side of the first magnetic piece 21a is shown in the figure) to the vicinity of the connecting portion 23 to form two legs. This groove 27
A bobbin 47 forming a drive coil is attached to the outer peripheral surface 5 of the lens holder 3 between the two. In the lens holder 3,
A space 48 is formed in which the groove 27 formed in the first and second magnetic pieces 21a and 21b is open.
The electrodes used in the fusing method are to enter there. Next, as shown in FIGS. 16C and 16D, a wire terminal 35 is attached to the magnetic plate 20 by a fusing method, and the wire is wound around the bobbin 47 so that the drive coil 13
a is formed. By doing so, the coil winding step can be automated, and the number of components can be reduced.

(Embodiment 5) FIG. 17 is a perspective view showing a lens holder of an objective lens driving device according to Embodiment 5 of the present invention. In addition, the objective lens driving device of this example is
Since the basic configuration is the same as that of the objective lens driving device described in the fourth embodiment, common portions are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 17, the lens holder 3 of the objective lens driving device of this embodiment is provided with focusing driving coils 13a and 13b (only the focusing driving coil 13a is shown in the figure). And two first magnetic plates 20a having first and second magnetic pieces 21a and 21b disposed in portions to be moved, and tracking drive coils 12a and 12b (only the side of the tracking drive coil 12a is shown in the drawing. ) Are provided at the portion where the first and second magnetic pieces 21a and 21b are arranged.

The lens holder 3 has two first slits 50 into which the two first magnetic plates 20a can be inserted and fixed.
a, and two second slits 50b into which the two second magnetic plates 20b can be inserted and fixed. The first slit 50a is provided at the position sandwiching the shaft hole 4 at the outer peripheral surface 5.
Are cut vertically downward from the upper surface 14 of the lens holder 3 so that the portions where the focusing drive coils 13a and 13b are attached are cut. Further, the vicinity of the shaft hole 4 of the first slit 50a is a curved portion 51 formed so as to avoid the shaft hole 4.

Similarly to the first slit 50a, the second slit 50b is provided at the position sandwiching the shaft hole 4 at the outer peripheral surface 5b.
Are cut vertically downward from the upper surface 14 of the lens holder 3 so as to cut into a portion where the tracking drive coils 12a and 12b are attached, and intersect with the first slit 50a. In addition, the second slit 50
The curved portion 51 formed so as to avoid the shaft hole 4 also near the shaft hole 4 of b.

The first magnetic plate 20a inserted and fixed in the first slit 50a has a step 30 which is recessed upward in the connecting portion 23, as shown in FIG. On the other hand, no step 30 is formed in the second magnetic plate 20b inserted and fixed in the second slit 50b.
Therefore, the first magnetic plate 20a does not contact the second magnetic plate 20b. Also in this example, the tracking magnet 10
a, 10b and focusing magnets 11a, 11b
Since the first and second magnetic pieces 21a and 21b that hold the lens holder 3 at a predetermined neutral position in opposition to the above are connected by the connecting portion, it is easier than mounting the magnetic pieces one by one. Can be attached. In this example, the first and second magnetic plates 20a and 20b
In addition, since it is fixed to the second slits 50a and 50b, the positioning can be performed with higher precision than when it is fixed with an adhesive or the like. Therefore, it is possible to suppress variations in the focusing and tracking drive sensitivities of the lens holder 3.

In this example, the first and second magnetic plates 20
a and 20b have conductivity, and the first magnetic plate 20a
Are used as a part of a power supply path of the focusing drive coils 13a and 13b, and the second magnetic plate 20b is used as a part of a power supply path of the tracking drive coils 12a and 12b.

FIG. 19 is a plan view schematically showing the power supply paths of the tracking driving coils 12a and 12b and the focusing driving coils 13a and 13b of the objective lens driving device 1 of this embodiment. As shown in this figure, the plus terminal 32 and the minus terminal 36 of the focusing drive coils 13a and 13b are arranged near one focusing drive coil 13b. One terminal 33 on the plus side of the focusing drive coil 13b is connected to its plus terminal 32. In addition, of the two first magnetic plates 20a, one of the first magnetic plates 20a has a terminal 35 on the minus side of one of the focusing magnets 13b,
Terminal 3 on the plus side of the other focusing magnet 13a
8 are connected. The other first magnetic plate 20a has a terminal 3 on the minus side of the other focusing magnet 13a.
7 are connected to the minus terminals 36 of the focusing drive coils 13a and 13b.

Also, one tracking drive coil 1
2b, the tracking drive coils 12a, 12
The plus terminal 39 and the minus terminal 42 of b are arranged. One terminal 40 on the plus side of the tracking drive coil 12b is connected to its plus terminal 39. Also, of the two second magnetic plates 20b, one of the second magnetic plates 20b has a terminal 41 on the minus side of one of the tracking magnets 12b and the other of the tracking magnets 12a.
Is connected to the other end of the tracking magnet 12 and the tracking drive coils 12a and 12b.
Negative terminal 42 is connected.

As described above, the objective lens driving device 1 of this embodiment
However, since the two drive coils disposed at the diametrically opposed positions of the lens holder 3 are electrically connected to each other by the magnetic plates 20a and 20b, the lead wires and the like are not routed inside and outside the lens holder 3. You may. Therefore, since it is not necessary to consider the lead wire routing structure, the design of the power supply system of the tracking drive coil 12 and the focusing drive coil 13 is simplified.

[0059]

As described above, the objective lens driving device according to the present invention utilizes the magnetic drive circuit for driving the lens holder, and the first and second lens holders hold the lens holder at a predetermined neutral position. Are connected by a connecting portion made of a magnetic member. Therefore,
Compared with the case where magnetic pieces are attached one by one, the number of parts to be attached to the lens holder can be reduced, and the number of work steps can be reduced. Further, since the connecting portion forms a part of the magnetic path of the magnetic drive circuit, the magnetic flux generated by the magnet of the magnetic drive circuit can be effectively used. Therefore, the efficiency of the magnetic drive circuit can be improved.

[Brief description of the drawings]

FIG. 1A is a plan view illustrating an objective lens driving device according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view illustrating a portion taken along line AA in FIG. .

FIGS. 2A to 2C are perspective views showing how a magnetic plate is attached to a lens holder of the device shown in FIG.

FIGS. 3A and 3B are explanatory diagrams showing a magnetic drive circuit for focusing of the apparatus shown in FIG. 1;

FIG. 4 is an explanatory diagram showing a focusing magnetic drive circuit of a conventional objective lens drive device.

FIG. 5A is a front view showing a modification of the magnetic plate,
(B) is a side view of the magnetic plate shown in (a), (c) is
(A) is a front view showing a modification of the lens holder using the magnetic plate shown in (b), (d) is a cross-sectional view showing a portion cut along line BB in (c), (e) )
(A) and (b) are front views showing a state in which the magnetic plate is attached to a lens holder.
It is sectional drawing which shows the part cut | disconnected by the -C line.

FIGS. 6A to 6D are perspective views showing modified examples of the magnetic plate.

FIGS. 7A and 7B are perspective views showing a lens holder of the objective lens driving device according to the second embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a tracking magnetic drive circuit of an apparatus using the lens holder shown in FIG. 7;

FIG. 9 is an explanatory diagram showing a tracking magnetic drive circuit of a conventional objective lens drive device.

FIG. 10A is a perspective view showing a lens holder of the objective lens driving device according to the third embodiment of the present invention, and FIG.
Is a perspective view showing a magnetic plate used in the device shown in FIG.
(C) is a perspective view showing a lens holder to which a magnetic plate is attached by insert molding.

11A is a perspective view showing a lens holder to which two magnetic plates are attached by insert molding, and FIG.
It is a perspective view which shows the magnetic plate attached to the lens holder shown to (a).

FIG. 12 is a perspective view showing a lens holder of the objective lens driving device according to Embodiment 4 of the present invention.

13A and 13B are perspective views showing a magnetic plate used in the device shown in FIG.

FIG. 14 is a schematic diagram showing a power supply path of a drive coil of the device shown in FIG.

FIGS. 15A to 15E are perspective views showing a state where a terminal of a drive coil is connected to a magnetic plate.

FIG. 16 (a) is a front view showing a part for forming a drive coil when the step of attaching the end of the drive coil to the magnetic plate and the step of forming the drive coil are performed consistently, and FIG. 16 (b).
Is a cross-sectional view showing a portion cut along the line DD in FIG.
(C) is a front view showing a state in which a drive coil is formed in the device shown in (a), and (d) is a cross-sectional view showing a part cut along line EE in (c).

FIG. 17 is a perspective view showing a lens holder of the objective lens driving device according to the fifth embodiment of the present invention.

18A and 18B are perspective views showing a magnetic plate of the device shown in FIG.

19 is a schematic diagram showing a power supply path of a drive coil of the device shown in FIG.

[Explanation of symbols]

 Reference Signs List 1 Objective lens driving device 2 Objective lens 3 Lens holder 5 Outer peripheral surface of lens holder 6 Support shaft 7 Holder support member 10a, 10b Tracking magnets 11a, 11b Focusing magnets 12a, 12b Tracking drive coils 13a, 13b Focusing drive coils Reference Signs List 20 magnetic plate 20a first magnetic plate 20b second magnetic plate 21a first magnetic piece 21b second magnetic piece 23 connecting portion L axis

Claims (9)

[Claims] 1. A magnetic drive circuit for moving a lens holder holding an objective lens in a tracking direction and a focusing direction, and a magnetic attraction force for holding the lens holder at a predetermined neutral position using the magnetic drive circuit. An objective lens driving device having a neutral position holding means for generating the first and second magnetic pieces fixed to the lens holder, and the first and second magnetic pieces fixed to the lens holder. And a connecting part made of a magnetic material connected to the objective lens driving device. 2. The objective lens driving device according to claim 1, comprising a plurality of said neutral position holding means. 3. The method according to claim 1, wherein the first and second magnetic pieces and the connecting portion have conductivity.
An objective lens driving device wherein these parts are used as a part of a power supply path for the magnetic drive circuit. 4. The method according to claim 1, wherein
An objective lens driving device, wherein both ends of the magnetic plate are bent to form the first and second magnetic pieces at the both ends of the magnetic plate, and a portion between these is the connection portion. 5. The objective lens driving device according to claim 4, wherein the lens holder is a resin molded product, and the magnetic plate is fixed to the lens holder by insert molding. 6. The objective lens driving device according to claim 4, wherein a slit is formed in the lens holder, and the magnetic plate is inserted and fixed in the slit. 7. The magnetic head according to claim 4, wherein the lens holder is rotatably supported in a tracking direction and movable in a focusing direction by a holder support member and a support shaft which are fixedly arranged. The drive circuit has a tracking magnetic drive circuit for moving the lens holder in a tracking direction and a focusing magnetic drive circuit for moving the lens holder in a focusing direction, and the tracking magnetic drive circuit includes an outer periphery of the lens holder. A pair of tracking drive coils mounted at diametrically opposed positions on the surface, and a pair of tracking magnets mounted at positions facing the respective tracking drive coils on the side of the holder support member. Magnetic drive circuit for the lens It has a pair of focusing drive coils attached at diametrically opposed positions on the outer peripheral surface of the holder, and a pair of focusing magnets attached at positions facing the respective focusing drive coils on the holder support member side. The magnetic plate may be configured such that the first and second magnetic pieces formed at both ends of the magnetic plate face the pair of focusing magnets or the pair of tracking magnets. An objective lens driving device mounted on a holder. 8. The method according to claim 7, wherein:
A first magnetic plate, wherein the first magnetic plate has a state in which the first and second magnetic pieces formed on both ends of the magnetic plate face a pair of the focusing magnets; Attached to the lens holder so that
The second magnetic plate is attached to the lens holder such that the first and second magnetic pieces formed at both ends of the magnetic plate face a pair of the tracking magnets. An objective lens driving device characterized by the above-mentioned. 9. The device according to claim 8, wherein the first magnetic plate is used as a power supply path connecting between the pair of focusing drive coils, and the second magnetic plate is connected to the pair of focusing drive coils. An objective lens driving device, which is used as a power supply path connecting between tracking driving coils.