JPH1064111A - Objective lens drive - Google Patents

Abstract

(57) [Problem] In a conventional moving magnet type objective lens driving device, since the bobbin is fixed only on one side (upper or lower) of the yoke, it is difficult to secure the inclination accuracy. SOLUTION: An objective lens 1, a holder 2 for holding the objective lens 1, a magnet 3 fixed to the holder 2, a yoke 6 which is a magnetic material disposed to face the magnet 3, and a yoke 6 , A flexible substrate 13 electrically connected to the coils 8 and 9, and a base 12 as a fixed-side member, and positioning portions are provided at four corners of the bobbin 7. Base 1
The position and the inclination accuracy can be easily secured by fixing by fitting with a receiving portion provided at 3 or the like.

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 used in an optical disc reproducing apparatus for projecting a laser beam onto a disc to record and reproduce signals on the disc.

[0002]

2. Description of the Related Art In recent years, an objective lens driving device has been developed to use a CD-R.
In response to the technical trend of increasing the speed of an optical disc such as an OM drive, a moving magnet system in which a coil is wound around a movable portion including an objective lens, and a moving magnet system in which a magnet is arranged in the movable portion are expected to become the mainstream in the future. The moving magnet system has a magnet on the movable part and a yoke and coil on the fixed side, so the rigidity of the movable part is increased, enabling a broadband control corresponding to a high rotation speed of the disk. There is no coil around the lens and the lens is not distorted due to the heat of the coil. However, there is a disadvantage that the connection of a plurality of coils is slightly complicated.

FIG. 3 is an exploded perspective view showing a component configuration of an optical pickup including a conventional objective lens driving device. FIG.
, 51 is an objective lens, and 52 is an objective lens 5
Holders 1 and 53a and 53b are holders 5
The magnets 54a, 54b fixed to the holder 2 are metal terminals 55a, 55 pressed into grooves formed in the holder 52.
b, 55c, and 55d are four metal springs. 56
Is a metal plate, a gel holder 5 formed of a transparent resin.
Along with 6, it is screwed and fixed to a base 59 formed by zinc die casting with a screw 57. Metal spring 55
a, 55b, 55c, and 55d have respective ends.
The holder 52 is cantilevered by being soldered and fixed to the metal plate 56 and the metal terminals 54a and 54b, respectively. In the gel holder 58, a silicon gel 60 is gelled after being injected, and the metal springs 55a, 55b,
The vibration of 55c and 55d is damped. An iron yoke 61 is insert-molded on the bobbin 62, and a focus coil 63 and a tracking coil 64 are wound therearound. On the lower surface of the bobbin 62, terminal pins 65 made of four rectangular hard copper wires are press-fitted, and a focus coil 63 and a tracking coil 64 are provided.
The winding start and end terminals are wound around respective terminal pins. Reference numeral 66 denotes a flexible board for making an electrical connection to the coil. Two bobbins 62
Must be kept parallel to the magnets 53a, 53b, so that the bosses 59a, 59b, 59
The bobbin 57 and the base 59 are held in a state where the vertical surfaces of the two bobbins 62 are pressed against the c and 59d to secure the verticality of the bobbin.
The bobbin 57 is fixed by pouring an adhesive therebetween. After the fixing, a total of eight terminal pins 65 of the two bobbins 62 protrude from the lower surface of the base 59, are inserted into holes of the flexible board 66, and are soldered to circuit lands provided there. The power supply land 6 is provided on the flexible substrate 66.
6a, the focus coil 63 wound around the bobbin 62 and the tracking coil 64 can be energized from the outside by being connected to the connection land 71a of the flexible substrate 71 of the optical pickup by soldering. 67 is
It is a resin cover, and the metal springs 55a, 55b, 55
c, 55d is protected.

The principle of operation is that the magnet 53 is magnetized by NS in the thickness direction, and forms a magnetic circuit with the yoke 61 facing the magnet. Since the focus coil 63 and the tracking coil 64 are wound in a direction perpendicular to the lines of magnetic force, a magnetic field is generated when energized, and a reaction is applied to the magnet to drive the lens in the focus direction and the tracking direction. .

[0005] Components of an optical pickup equipped with an objective lens driving device will also be described. 69 is a mirror,
68 is an optical base, 70 is a laser hologram unit in which a semiconductor laser, a light receiving element and a hologram element are integrated, 72 is a metal heat sink attached to the back of the laser hologram unit, and 73 is a laser hologram unit 70 Are fixed to the optical base 68, and screws 74a and 74b are screwed into the screw holes provided in the base 59 to adjust the inclination of the entire objective lens driving device including the objective lens 51. It is. In addition, 75
A spring 76 for slidably pressing the base 59 against the optical base 68 and a fixing screw 76 are provided.

[0006]

However, in the above-described objective lens driving device, the base 59 for receiving the bobbin 62 must have a positioning portion such as a boss in order to maintain the verticality of the bobbin 62. It was necessary to bond and fix 62 in that state.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, an object of the present invention is to provide an objective lens driving device which does not require an adhesive necessary for fixing and has improved assembling workability. Things.

[0008]

In order to solve this problem, an objective lens driving device according to the present invention is provided with positioning portions at four corners of a bobbin and fixing them by fitting with a receiving portion provided on a base or the like. By the inclination of the bobbin (yoke),
Position accuracy can be easily ensured. In addition, by fixing the bobbin by welding the boss of the member on the bobbin receiving side, the positioning of the bobbin is uniquely determined, and an adhesive for fixing can be eliminated.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention provides an objective lens, a lens holder for holding the objective lens, a magnet fixed to the lens holder, and a plurality of supports for supporting the lens holder. A metal spring,
The yoke is a magnetic material disposed opposite to the magnet, a bobbin made of a resin material for holding the yoke by insert molding, two coils wound around the bobbin, and one of fixed-side members. An objective lens driving device comprising a base, wherein the bobbin has positioning portions at four corners, and is fixed by fitting with a receiving portion provided on the base or the like. Since the fixing portion is located at a remote position, the position and the tilt accuracy can be improved, and the vibration of the bobbin can be suppressed.

According to a second aspect of the present invention, the positioning portion of the bobbin or the receiving portion provided on the base or the like allows play in the direction of the magnet opposed to each other so that the bobbin can be easily fitted together, and is inserted. 2. The objective lens driving device according to claim 1, wherein the bobbin is tapered so that the bobbin becomes parallel to the magnet. When the bobbin is fitted to the portion, the bobbin can be easily inserted even if it is attracted to the magnet, and finally, the bobbin has an effect of being able to be in a parallel posture with the facing magnet.

According to a third aspect of the present invention, an objective lens is provided.
A lens holder for holding the objective lens, a magnet fixed to the lens holder, a plurality of metal springs for supporting the lens holder, a yoke made of a magnetic material arranged to face the magnet, and an insert for the yoke A bobbin made of a resin material to be molded and held;
The bobbin is provided with two coils wound around the bobbin and a base as one of the fixed side members, and the bobbin is crimped by welding a positioning portion such as a boss provided on a receiving member such as the base. The objective lens driving device is characterized in that it does not require an adhesive for fixing and can significantly improve bobbin positioning and fixing workability.

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an exploded perspective view showing a component configuration of an objective lens driving device including the objective lens driving device according to the first embodiment of the present invention. In FIG.
1 is an objective lens, 2 is a holder for holding the objective lens 1, 4a, 4b, 4c, and 4d are four metal springs, 5
Is a frame for holding the four metal springs. Here, the holder 2, the frame 5, the four metal springs 4a,
4b, 4c, and 4d are obtained as a single product from the same mold by insert molding this metal spring. In this state,
The holder 2 has four metal springs 4a, 4b, 4c, 4d
Is cantilevered. Reference numerals 3a and 3b denote magnets that are adhered and fixed to the holder 2. Further, an iron yoke 6a is insert-molded on the bobbin 7a, around which a focus coil 8a and a tracking coil 9a are formed.
Is wound. Four grooves are formed at both ends of the upper surface of the bobbin 7a, and the ends of the focus coil 8a and the start and end of winding of the tracking coil 9a are wound around the respective grooves. These two bobbins 7
a and 7b are fixed to the frame 5 (described in detail in FIG. 2). Reference numeral 10 denotes a gel holder, which is formed in a box shape by the frame 5 and the bobbin 7b. Reference numeral 12 denotes a base formed of a sheet metal, and has a function of a bone for mounting the frame 5. Reference numeral 13 denotes a flexible substrate for electrically connecting the coil. 14 is the flexible substrate 13
And the frame 5 are integrally screwed together.

The components of an optical pickup equipped with an objective lens driving device will also be described. 16 is a mirror,
Reference numeral 15 denotes an optical base, 17 denotes a laser hologram unit in which a semiconductor laser, a light receiving element and a hologram element are integrated, 19 denotes a metal heat sink attached to the back of the laser hologram unit, and 18 denotes a flexible optical pickup. The substrate 20 includes a fixing spring for fixing the laser hologram unit 17 to the optical base 15,
1 a and 21 b are screws for adjusting the inclination of the entire objective lens driving device including the objective lens 1 by fitting into a screw hole provided in the base 12. 22 is the base 1
2 for slidably pressing the optical base 2 against the optical base 15;
23 is a fixing screw.

FIG. 2 is a detailed explanatory view of a method of fixing the bobbin of the objective lens driving device according to the first embodiment of the present invention. On the lower surfaces of the bobbins 7a and 7b, two positioning bosses 24a and 24b and 24c and 24d are provided, respectively. These bosses 24a, 24b, 24c, 24d are tapered 25 in the direction of the magnets 3b, 3c facing each other.
a, 25b, 25c, and 25d are applied. These bosses 24a, 24b, 24c, 24d are respectively attached to the base 12
When inserted into the holes 28a, 28b, 28c, 28d, the tapered portions 25a, 25b, 25c, 25d can be easily inserted. As it is inserted, the bobbins 7a, 7b gradually assume a vertical posture, and can eventually maintain a parallel posture with the magnets 3a, 3b facing each other. While inserting the bosses 24a, 24b, 24c, 24d into the holes 28a, 28b, 28c, 28d, the holes 26a, 26 which are upper positioning portions of the bobbins 7a, 7b.
b, 26c and 26d are inserted into bosses 27a, 27b, 27c and 27d which are receiving portions provided on the fixing frame 5. After insertion, the bosses 27a, 27 on this frame 5
The bobbins 7a, 7b are fixed on the frame 5 by caulking b, 27c, 27d by welding or the like.

The operation of the objective lens driving device configured as described above will be described below.

In FIG. 1, magnets 3a and 3b are
NS is magnetized in the thickness direction, and forms a magnetic circuit with the opposed yokes 6a and 6b. Focus coil 8
Since a and 8b and the tracking coils 9a and 9b are wound in a direction perpendicular to the lines of magnetic force, a magnetic field is generated by energizing, and the reaction of the force is applied to the magnet. Further, the holder 2 has four metal wires 4a, 4
Since the cantilever is supported by b, 4c, and 4d, the objective lens 1 and the holder 2 can be driven in the focus direction and the tracking direction by the reaction of this force.

As described above, according to the present embodiment, since the bobbins 7a and 7b have positioning portions other than the fixed portions, the bobbins 7a and 7b can be easily positioned while maintaining the parallelism with the opposed magnets 3a and 3b. it can. In addition, bobbin 7
Since the fixing portions a and 7b are simply inserted into the boss of the receiving portion and swaged by welding or the like, the assembling workability can be improved.

[0018]

As described above, according to the present invention, in a moving magnet type objective lens driving device, a reference surface is provided on a bobbin receiving portion so as to fix a bobbin so far with a parallelism between the magnet and an opposing magnet. It was necessary to adhere while pressing the opposing surface of the bobbin against it, but by holding the positioning parts at the four corners of the bobbin and fixing it by fitting with the receiving part provided on the base etc., The effect that the assembling workability is greatly improved can be obtained. In addition, since the positioning part is located at a distance, inclination,
Position accuracy can be improved, and bobbin vibration can be suppressed.

Further, by tapering the positioning portion of the bobbin or the receiving portion such as the base, the positioning portion can be easily inserted into the receiving portion even if attracted to the magnet, and finally, the positioning portion and the base can be opposed to each other. Between them, the parallelism can be secured.

Further, the position of the bobbin is determined by a positioning portion such as a boss of the receiving side member, and the bobbin is fixed by caulking the positioning portion, thereby eliminating the adhesive necessary for fixing the bobbin. In addition, it is also possible to caulk all the positioning portions at the same time, and the number of steps can be reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an objective lens driving device according to an embodiment of the present invention.

FIG. 2 is a detailed explanatory diagram of a bobbin fixing method of the objective lens driving device according to the embodiment;

FIG. 3 is an exploded perspective view of an objective lens driving device including a conventional objective lens driving device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Objective lens 2 Holder 3 Magnet 4 Metal spring 5 Frame 6 Yoke 7 Bobbin 8 Focus coil 9 Tracking coil 10 Gel holder 11 Gel 12 Base 13 Flexible substrate 15 Optical base 16 Mirror 17 Laser hologram unit 18 Optical pickup flexible substrate 19 Heat radiation Plate 20 Fixing spring 21 Adjustment screw 22 Spring 23 Fixing screw 24 Lower positioning portion (boss) provided on bobbin 25 Tapering process performed on lower positioning portion (boss) provided on bobbin 26 Upper portion provided on bobbin Positioning part (hole) 27 Receiving part (boss) of upper positioning part of bobbin provided on frame 28 Receiving part (hole) of lower positioning part of bobbin provided on base

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yukio Fishing Boat 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Takayuki Kojima 1006 Kazuma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co. (72) Inventor Masayuki Ito 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. An objective lens, a lens holder for holding the objective lens, a magnet fixed to the lens holder, a plurality of metal springs for supporting the lens holder, and a magnetic material arranged to face the magnet. , A bobbin made of a resin material that holds the yoke by insert molding, two coils wound around the bobbin, and a base that is one of the fixed-side members. An objective lens driving device having a positioning portion and being fixed by fitting with a receiving portion provided on the base or the like. 2. The bobbin positioning portion, or a receiving portion provided on the base or the like, allows play in the direction of the opposed magnets so that both can be easily fitted together, and as the bobbin is inserted, the bobbin moves toward the magnet. 2. The objective lens driving device according to claim 1, wherein a taper process is performed so as to be parallel to the magnet. 3. An objective lens, a lens holder for holding the objective lens, a magnet fixed to the lens holder, a plurality of metal springs for supporting the lens holder, and a magnetic material disposed to face the magnet. A bobbin made of a resin material for holding the yoke by insert molding, and a bobbin wound around the bobbin.
With two coils and a base that is one of the fixed side members,
The objective lens driving device, wherein the bobbin is fixed by fixing a positioning portion such as a boss provided on a receiving member such as the base by welding or the like.