JPH11283262A - Optical pickup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve sensitivity in acceleration without increasing the number of windings by dividing a focusing coil into inner and outer side parts, directly winding the inner side part in the winding grooves formed on the outer peripheral section of a lens holder and winding the outer side part on a tracking coil. SOLUTION: In the case of winding five layers of a focusing coil on a lens holder 40, the layers are divided into three layers of an inner side part 14a and two layers of an outer side part 14b, for example. The part 14a is directly wound in winding grooves 40b and the part 14b is wound on a tracking coil 45. Completing the above structure, no increase is made for the number of windings of the focusing coil as a whole, no increase is made in the direct current resistance and the mass and the parts 14b are made closer to a magnet. Thus, the magnetic driving force between the focusing coil and the magnet is increased and sensitivity in acceleration in the focus adjusting direction of the optical pickup is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup used in an optical disk driver, and more particularly to an optical pickup in which a magnetic drive mechanism for displacing a lens holder holding an objective lens is improved to improve acceleration sensitivity.

[0002]

2. Description of the Related Art A conventional optical pickup used in an optical disk drive for reading information recorded on an optical disk is configured as shown in, for example, a plan view of FIG. The optical pickup shown in this figure includes a lens holder 40 that holds an objective lens 50, an actuator base (not shown) that supports the lens holder 40 so that the lens holder 40 can be displaced up and down and left and right. And a driving device (to be described later).

The lens holder 40 is displaceably supported by four (only two of them are shown) suspension wires 47. On both upper and lower surfaces of the lens holder 40, suspension wires 47 are respectively provided at positions near both side edges.
Are provided (total of four protrusions) for fixing.

The rear end of the suspension wire 47 is fixed to the projection 71 of the damper base 70. The damper base 70 also has a damper holder 7 filled with a semi-liquid resin damping material for suppressing vibration of the suspension wire 47.
2 is provided, and the suspension wire 47 extends toward the lens holder 40 through the damping material. The damper base 70 is fixed to an actuator base (not shown).

A suspension wire 47 applied between the lens holder 40 and the damper base 70 as described above.
Is a mounting piece 47-1 made of a conductive metal and having a hole for press-fitting the projection 71 and a mounting piece 47-2 having a hole for press-fitting the projection 48. Have. The distal end of the suspension wire 47 is extended to a position near the distal end of the lens holder 40, and is soldered to the ends of a tracking coil and a focusing coil described later at this extended portion. This is the suspension wire 47
This has a function of supporting the lens holder 40 and a function of supplying current to the tracking coil and the focusing coil.

As shown in FIG. 5, a concave-shaped winding groove 40b for a focusing coil is formed on the side surface of the lens holder 40 so as to cover the entire circumference, and the focusing coil 14 extends along the winding groove 40b. It is wound.
First and second tracking coil winding frames 41 and 42 protrude from one of the longitudinally opposed side surfaces of the lens holder 40, and third tracking coil winding frames 43 and 42 form the other. A fourth tracking coil winding frame (see FIG. 4) protrudes. These winding frames include first to third tracking coils 45a and 45a.
b, 45c and a fourth tracking coil (not shown) are wound.

[0007] Two sets of magnetism generating portions, each of which is composed of a yoke 11 and a magnet 12, which are superposed on each other, are fixed to the actuator base. The first and second tracking coils 45a and 45b are opposed to one magnetic generator, and the third tracking coil 45c and the fourth tracking coil are opposed to the other magnetic generator.

A driving device for displacing the lens holder 40 includes first to fourth tracking coils 45a to 45d and a focusing coil 14 wound around the lens holder 40, a yoke 11 provided on an actuator base, and a magnet. And a magnetism generating unit 12. With this driving device, the lens holder 40
Is displaced with respect to the actuator base in the vertical direction, that is, the focusing direction, and the horizontal direction, that is, the tracking direction.

FIGS. 6A and 6B are a plan view and a side view showing the lens holder 40 in a partially enlarged manner in detail. The yoke 11 has two arms 11a and 11b.
A magnet 12 is fixed to one of the arms 11a. The other arm 11b
Penetrates the hole 40c formed in the lens holder 40 in a non-contact manner.

In recent years, the rotational speed of an optical disk has been increasing more and more, and accordingly, an optical pickup having high acceleration sensitivity has been required. Acceleration sensitivity is the ability of the optical pickup to follow the disk, so development is being promoted on one side in terms of reducing the size and weight of the optical pickup itself. The acceleration sensitivity can also be increased by increasing the number of windings of the coil to increase the magnetic driving force.

[0011]

However, when the number of windings of the coil is increased, the mass and the DC resistance increase accordingly. If the diameter of the coil is increased in order to reduce the DC resistance, the mass is further increased and the weight is reduced. This is a problem to be solved by the present invention.

According to the present invention, by changing the mode of the winding,
It is an object of the present invention to provide an optical pickup capable of improving acceleration sensitivity without increasing the number of turns.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens holder including an objective lens for an optical pickup, a winding groove for winding a focusing coil formed on an outer peripheral portion of the holder, and A focusing coil wound around the winding groove, a plurality of winding frames for winding a tracking coil formed projecting from the side surface of the holder, and a tracking coil sequentially wound around the plurality of winding frames,
A suspension wire for supporting the lens holder, wherein the focusing coil is divided into an inner part and an outer part, the inner part is directly wound around the winding groove, and the outer part is provided on the tracking coil. This can be achieved with a wound optical pickup.

According to the embodiment of the present invention, a magnet fixed to a position distant from the holder is provided near the lens holder. In one embodiment of the present invention, the magnet is fixed to an opposing yoke, and a part of the yoke penetrates a yoke penetrating hole formed in the holder in a non-contact manner. In another embodiment of the present invention, the magnet is fixed to a part of a frame, and the holder has no hole for yoke penetration.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments shown in the drawings. FIG. 1 is a sectional view showing a first embodiment of a lens holder 40 of an optical pickup according to the present invention. In this figure, reference numeral 14a denotes an inner portion of the focusing coil 14, and 14b denotes an outer portion of the focusing coil 14. If the conventional focusing coil 14 has a total of five layers of turns, the present invention divides it into, for example, three inner layers 14a (for example, 50 turns) and two outer layers 14b (for example, 30 turns). . The inner portion 14a is directly wound around the winding groove 40b, and the outer portion 14b is
5. Wind on top. In this case, specifically, the diameter of the conductor used for the tracking coil 45 is, for example, φ0.09 mm.
The diameter of the conductor used for the focusing coil is, for example, φ0.1 mm.

In the winding structure shown in FIG. 1, the number of windings of the entire focusing coil 14 is the same as that of the prior art. Therefore, there is no increase in DC resistance and mass. Conventionally, the focusing coil 14 is located only below the tracking coil 45 and is far from the magnet 12, but according to the present invention, only the outer portion 14b is close to the magnet 12. For this reason, the magnetic driving force between the focusing coil 14 and the magnet 12 increases, and the acceleration sensitivity improves. In the winding structure shown in FIG. 1, there is no such a problem on the tracking coil 45 side. Therefore, by forming the outer portion 14b on the focusing coil 14, the acceleration sensitivity of the optical pickup in the focus adjustment direction is improved.

FIG. 2 is a sectional view showing a second embodiment of the lens holder 40 of the optical pickup according to the present invention. In this example, a U-shaped opposed yoke 11 is used.
The magnet 12 is fixed to one of the arms 11a. The other arm 11b of the yoke 11 is
Through the yoke through hole 40c without contact. The magnetic drive unit using such an opposing yoke 11 has higher acceleration sensitivity than the embodiment of FIG. 1 if other conditions are the same, and can cope with, for example, a drive at 32 times or more speed. .

FIG. 3 is a plan view showing a third embodiment of the lens holder 40 of the optical pickup of the present invention. In this example, instead of using the opposed yoke 11 to improve the acceleration sensitivity as in the embodiment of FIG. 2, the acceleration sensitivity is improved without using the yoke. That is,
The hole 40c for yoke penetration is not formed in the lens holder 40. Due to this structural change, the rigidity of the holder 40 is increased, and the higher-order resonance frequency can be increased. Further, since the yoke 11 is not used, the thickness of the entire optical pickup can be reduced. When a yoke is not used as in this example, the magnet 12 is fixed to a part of the frame 80 of the optical pickup.

[0019]

As described above, according to the present invention, since the mode of the winding is changed, the number of windings can be increased without increasing the number of windings.
An optical pickup capable of improving acceleration sensitivity can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a lens holder of the present invention.

FIG. 2 is a perspective view showing a second embodiment of the lens holder of the present invention.

FIG. 3 is a plan view showing a third embodiment of the lens holder of the present invention.

FIG. 4 is a plan view showing an example of a conventional optical pickup.

FIG. 5 is a perspective view of the lens holder of FIG. 4;

6A and 6B are a plan view and a side view showing a part of the periphery of the lens holder of FIG. 4 in an enlarged manner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Opposing yoke 11a One arm part 11b The other arm part 12 Magnet 14 Focusing coil 14a Inner part 14b Outer part 40 Lens holder 40b Winding groove of focusing coil 40c Hole for yoke penetration 41-44 Reel frame of tracking coil 45 Tracking Coil 47 Suspension wire 50 Objective lens 80 Frame

Claims (4)

[Claims] 1. A lens holder including an objective lens for an optical pickup, a winding groove for winding a focusing coil formed on an outer peripheral portion of the holder, and a focusing coil wound around the winding groove. A plurality of winding frames for winding a tracking coil formed so as to protrude from a side surface of the holder, a tracking coil wound in order on the plurality of winding frames, and a suspension wire for supporting the lens holder. Wherein the focusing coil is divided into an inner part and an outer part, the inner part is wound directly on the winding groove, and the outer part is wound on the tracking coil. pick up. 2. The optical pickup according to claim 1, wherein a magnet fixed to a position distant from the holder is provided near the lens holder. 3. The optical pickup according to claim 2, wherein the magnet is fixed to an opposing yoke, and a part of the yoke penetrates a hole for yoke penetration formed in the holder in a non-contact manner. 4. The optical pickup according to claim 2, wherein the magnet is fixed to a part of a frame, and the holder has no yoke through hole.