JPH0244527A - Objective lens driving device - Google Patents

Abstract

PURPOSE:To accurately fix a movable body and the hinge body of a supporting mechanism and to reduce the inclination of an optical axis in an objective lens by planting and contacting a metallic piece to an edge part to the movable body of the hinge body and fixing the edge part of the hinge body through this metallic piece to the movable body. CONSTITUTION:A synthetic resin made hinge body 34 of a supporting mechanism 31, which supports a movable body 21 movably in a focusing direction and a tracking direction on a base 11, is fixed through a metallic piece 51 to a notch part 24 of the movable body 21. The lower side of this metallic piece 51 is contacted to a contact reference surface 24a in the movable body 21 side as a contact reference surface 51a in the hinge body 34 side. Since high accuracy is obtained for the contact reference surface 51a of this metallic piece 51, the position accuracy of the movable body 51 can be easily obtained after assembly. Accordingly, it is reduced that the movable body 21 is inclined to a reference surface 11a of the base 11 and it is also reduced that the optical axis of an objective lens 26 is inclined.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an objective lens driver 1FIl device used for optical information recording media such as optical discs and optical cards.

(Prior Art) In devices that read signals from optical information recording media such as optical discs, signals are detected by focusing laser light onto the information recording medium using an objective lens. , focusing control to focus the light spot on the signal recording surface of the information recording medium and tracking control to make the light spot follow the signal track in response to the unevenness and vibration of the information recording medium. is necessary.

In order to perform these controls, an error detection device that detects errors in the focusing direction and the tracking direction, and an objective lens drive device that moves the objective lens to cancel these errors are required.

As this objective lens driving device, there is one shown in FIGS. 5 to 7.

In FIGS. 5 and 6, reference numeral 11 denotes a plate-shaped base, and this base 11 is made of a magnetic material such as iron, and has a circular through hole 12 bored from the center right end in the figure. A notch 13 is connected to the left side of the through hole 12, and a spherical seat 14 concentric with the through hole 12 is formed to bulge downward around the through hole 12.

A pair of pillars 1 are mounted on the left end of the base 11 in the figure.
6 are installed vertically, and yokes 17 are bent vertically and parallel to each other upwardly from both sides of the center of the base 11. A pair of yokes 18 on both sides made of the same magnetic material as the base 11 are integrally fixed perpendicularly and parallel to each other, and a magnet 19 is attached to the inside of each of the outer yokes 17, respectively. Fixed by

Reference numeral 21 denotes a movable body, and the movable body 21 is made of a non-magnetic material such as synthetic resin, and has a circular fitting recess 22 and a circular through hole 23 formed from the upper surface to the lower surface of the right end in the drawing. Convex notch FZ2 from the left end toward the center
4 is formed, rectangular mounting parts 25 are formed on both sides of the central part, and the fitting recess 22 has an objective lens 2.
6 are fitted and glued together, and focusing coils 27 wound into a rectangular tube shape are fitted and glued into the mounting recesses 25 on both sides, and from the outer surfaces of the focusing coils 27 on both sides to the outer surface of the movable body 21 are A pair of tracking coils, 28, are glued together.

The movable body 21 is mounted on the base 11 via a support mechanism 31 in the vertical focusing direction in FIG. 6 along the optical axis of the objective lens 26, and in the vertical focusing direction in FIG. is supported so as to be movable in the tracking direction.

That is, as shown in FIG. 7, the support structure 31 has left end portions of a pair of upper and lower metal leaf springs 33 planted in parallel on the right side of the support plate 32 made of synthetic resin. The right end portions of a pair of upper and lower leaf springs 33 are planted in one end portion 35 on the right side in the drawing of a hinge body 34 made of synthetic resin, and between the one end portion 35 of the hinge body 34 and the other end portion 36 on the left side in the drawing. A bendable thin hinge portion 37 is formed at the top and bottom, and one end portion 35 of the hinge body 34 is elastically moved relative to the support plate 32 in the vertical focusing direction in FIG. 6 by a pair of upper and lower leaf springs 33. The hinge part 37 of the hinge body 34 allows the other end 3G of the hinge body 34 to move elastically in the vertical tracking direction in FIG. 5 with respect to the one end 35 of the hinge body 34. It becomes.

The support mechanism 31 has the other end 3 of the hinge body 34.
G is fitted into the notch 24 of the movable body 21 and fixed by press-fitting or adhesive, and the pillars 16 of the base are fitted and fixed into a pair of support holes 38 formed in the support plate 32. , the movable body 21 is supported on the base 11, thereby supporting the movable body 21 so as to be elastically movable in the vertical focusing direction in FIG. 6 and in the vertical tracking direction in FIG.

Note that the other end 3 of the hinge body 34 of the support gIM431
In G, a metal cylindrical counterweight 39.40 for balancing the weight is embedded in advance by insert molding, and this counterweight 39.
．． 40, the movable body 21 is attached to the base 1 by the support mechanism 31.
1, the hinge part 37 of the hinge body 34 is located at the center of inertia of the movable parts such as the movable body 21, the objective lens 26, the focusing coil 21, the tracking coil 28, and the hinge body 34. Hinge part 37
The focusing coil 27 and the tracking coil 28 on both sides are located symmetrically with respect to the above.

Further, while the movable body 21 is supported on the base 11 by the support mechanism 31, the focusing coils 27 corresponding to the movable body 21 surround the inner yoke 18 on both sides of the base 11, and the focusing coils 27 on both sides surround the inner yoke 18 on both sides of the base 11. The outer part and the outer tracking coil 28 are connected to the magnetic gear 1 between the corresponding inner yoke 18 of the base 11 and the magnet 19.
? It is placed on the horn.

Then, this objective lens driver! With this configuration, the IJ device uses the spherical seat 14 of the base 11 for positioning with respect to the mounting partner, and fixes the base 11 to the mounting partner, and in this state, like a general objective lens drive device,
By sending control signals in the respective directions based on error detection in the focusing direction and the tracking direction to the focusing coil 27 and the tracking coil 28 disposed in the magnetic gap between the magnet 19 and the inner yoke 18, the focusing coil 27 and the tracking The coil 28 is driven with a force of 1i in the vertical focusing direction in FIG. 6 and in the vertical tracking direction in FIG. By driving this objective lens 26, the through hole 12 of the base 11 is opened.
The laser beam passing through the information recording medium is accurately focused on the signal recording surface of the information recording medium, and the focused light spot is made to reliably follow the signal track on the signal recording surface.

(Problems to be Solved by the Invention) However, the objective lens driving device described above has the following problems.

Hinge body 34 of support 1i1131 that fixes movable body 21
Since the other end portion 3G is molded from the same synthetic resin as the hinge portion 31, the contact reference surface on the lower side of the other end portion 36 of the hinge body 34 with respect to the contact reference surface 24a at the bottom of both sides of the cutout portion 24 of the movable body 21 It is difficult to obtain 3Ga accuracy, and the base 11 after assembly
The movable body 21 is tilted with respect to the reference plane 11a, and the optical axis of the objective lens 26 is also tilted.If this tilt is large, it cannot be corrected even if adjustments are made afterwards. There is a problem that the product is defective, and even if the inclination is within a correctable range, it takes time to make adjustments, etc., so it is required to reduce the inclination as much as possible.

The present invention has been made in view of these points, and an object of the present invention is to accurately fix the movable body 21 and the hinge body 34 of the support mechanism 31.

[Structure of the invention]

(Means for Solving the Problems) The present invention includes a movable body provided with an objective lens together with a focusing coil and a tracking coil, a base provided with a magnet and a yoke for the focusing coil and the tracking coil, and a movable body mounted on the base. a support mechanism that supports the movable body movably in a focusing direction along the optical axis of the objective lens and in a tracking direction intersecting the optical axis of the objective lens, and at least one of the focusing direction and the tracking direction of the movable body by the support mechanism. In the objective lens driver 8 device that uses a bendable synthetic resin hinge body for support, a metal piece is implanted at the end of the hinge body relative to the movable body, and the hinge body is moved through the metal piece. The end portion is fixed to the movable body.

(Function) The objective lens driving device of the present invention fixes a metal piece implanted in the hinge body to the movable body when fixing the synthetic resin hinge body of the support mechanism to the movable body.

(Embodiment) An embodiment of the objective lens driving device of the present invention will be described with reference to FIGS. 1 to 4.

The structure of this embodiment is basically the same as that described above with reference to FIGS. The parts shall be explained.

In this embodiment, a synthetic resin hinge body 34 of the support mechanism 31 is fixed to the notch 24 of the movable body 21 via a metal piece 51.

That is, in this embodiment, the other end 36 of the hinge body 34
is shortened, and a convex metal piece 51 formed by sheet metal pressing is implanted in this shortened part by insert molding. The contact reference surface 51 of this metal piece 51 will come into contact with the contact reference surface 24a on the 21 side.
Since high accuracy can be obtained in a, the movable body 21 after assembly is
The movable body 21 is less inclined to the reference plane 11a of the base 11, and the optical axis of the objective lens 26 is less likely to be inclined.

Therefore, the optical axis of the objective lens 26 has little inclination, and the inclination can be easily corrected by adjustment, etc., so the occurrence of defective products can be reduced, and the time required for adjustment, etc. can be shortened. .

Furthermore, in this embodiment, the metal piece 51 functions as a counterweight, and the cylindrical counterweights 39 and 40 shown in FIGS. 5 to 7 can be omitted, which increases manufacturing costs. On the contrary,
This metal piece 51 is a cylindrical counterweight 39.
Compared to 40, it can be easily and inexpensively made by sheet metal pressing, so the manufacturing cost can be reduced.

In addition, in FIG. 3, 52 is a flexible printed circuit board, and this printed circuit board I! The substrate 52 is 1.1
This is used for the 1611 signal line, and the movable body 21
and is connected to each of the coils 27 and 28.

In this embodiment, two leaf springs 33 made of gold III are used to support the movable body 21 in the focusing direction in the support mechanism 31, but a bendable synthetic resin hinge body may also be used. can.

〔Effect of the invention〕

As described above, according to the present invention, the objective lens driver movably supports the movable body provided with the objective lens on the base via the support mechanism including the hinge body made of synthetic resin. In the IIl device, a metal piece is implanted in the hinge body, and the hinge body and the movable body are fixed via this metal piece that provides high accuracy, so the position V accuracy of the movable body after assembly is 1! ? Since the optical axis of the objective lens is less likely to tilt, the tilt of the optical axis of the objective lens can be easily corrected by adjustment, etc., reducing the occurrence of defective products and reducing the time required for adjustment, etc. Can be shortened.

4. IFitll Explanation of the Drawings FIGS. 1 to 4 show an embodiment of the objective lens driving device of the present invention, FIG. 1 is a plan view thereof, FIG. 2 is a longitudinal sectional view thereof, and FIG. FIG. 4 is an exploded perspective view of the same, FIG. 4 is a perspective view of its support mechanism, FIGS. 5 to 7 show a conventional objective lens adjustment device, FIG. 5 is a plan view thereof, and FIG. , FIG. 7 is a perspective view of the support mechanism.

11... Base, 17. 18... Yoke, 19... Magnet, 21... Movable body, 26... Objective lens, 27...
- Focusing coil, 2B... Tracking coil, 31... Support mechanism, 34... Hinge body, 51... Metal piece.

Claims (1)

[Claims] (1) A movable body provided with an objective lens together with a focusing coil and a tracking coil; a base provided with a magnet and a yoke for the focusing coil and tracking coil; and a support mechanism movably supporting the movable body in the focusing direction and the tracking direction intersecting the optical axis of the objective lens. An objective lens driving device using a hinge body, wherein a metal piece is implanted at an end of the hinge body relative to the movable body, and the end of the hinge body is fixed to the movable body via the metal piece. An objective lens driving device characterized by: