JP2658177B2 - Objective lens actuator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an objective lens actuator of an optical disk memory device. More specifically, the present invention relates to a support mechanism for an objective lens.

[Conventional technology]

FIG. 4 is a view showing a supporting mechanism of a conventionally used objective lens actuator. The objective lens 1 is fitted and adhered to a lens holder (dotted line portion) 2.
The drive system actuator coils are installed on the left and right sides of the section. The holder 2 is further connected to a suspension 4 having a plurality of hinges at a leading portion 41. Further, the suspension 4 is pin-fixed to the main body substrate at the holes 42 and 43. Now, in the lens actuator having such a structure, focusing (vertical movement in the vertical direction in the figure) of the objective lens can be performed by deformation of the quadrilateral portion 44 of the suspension 4. That is, the corner 4 of the quadrilateral
The corners are hinges, and the suspension deforms from a rectangle to a parallelogram, so that the head 41 of the suspension 4 moves up and down with this change. Next, since the head 41 of the suspension 4 rotates in the horizontal plane about the hinge portion of the suspension 45 in the tracking of the objective lens, the objective lens 1 also rotates in the horizontal plane along with the rotation, and the linear movement in the tracking direction is simulated. Becomes Thus, in this lens actuator, the two-dimensional movement of the objective lens is skillfully performed by the suspension 4 integrally formed of plastic.

[Problems to be solved by the invention]

However, in the conventional example, the light 5 coming from the optical system is changed upward by the flip-up mirror 6 as shown in FIG.
Further, the actuator 7 must be installed above the optical system so as not to interfere with the coil 3. Therefore,
The conventional example has a disadvantageous structure for reducing the thickness of the head.

The present invention is to solve such a problem and to provide an objective lens actuator for realizing a thin optical head.

[Means for solving the problem]

An objective lens actuator according to the present invention includes: an objective lens that focuses a laser beam on a recording medium; a lens holder that holds the objective lens; and a plurality of hinges coupled to the holder and movable in a focus direction and a track direction. And three magnetic link members that move the objective lens in the focus direction and the track direction.

(Operation)

The present invention is a suspension having a link structure composed of three legs, and can freely move in the focus and track directions. Further, since the magnetic circuit does not block the laser light, it is possible to include a flip-up mirror in the lens actuator.

〔Example〕

FIG. 1 shows a suspension integrally molded with plastic according to the present invention. The movable parts 11 and 12 that stand parallel to the mounting part 100 to the substrate are connected by hinges 13 and 14, and can rotate in a horizontal plane. Two legs 15, 16 and one leg 17 extend from the movable portions 11, 12, respectively, and the roots are also connected by horizontal hinges 18, 19, 20. Therefore, the three feet can move up and down in the vertical direction. Furthermore, since the tips of these three feet have similar horizontal hinges 21, 22, 23 and the vertical hinges 24, 25, 26, the tips 27, 28, 29 of the three feet are attached to the lens holder. It does not hinder the vertical and horizontal movement of the three legs even if it is fixed to. That is, in the present invention, the link forms a link with the suspension integrally with the lens holder.

2 and 3 are a plan view and a side view, respectively, in which the suspension according to the present invention is incorporated in an actuator.
The objective lens 1 is fixed to a lens holder 2, and a pair of left and right actuator coils 3 are also fixed to the lens holder. This coil is inserted into a gap in a magnetic circuit including the permanent magnet 8 and the yoke 9. On the other hand, since the tips 27, 28, and 29 of the lens holder 2 are fixed and held by the suspension 10, when a current flows through the coil and a force is generated, the upper, lower, left, and right directions (focus and tracking directions) are restricted by the suspension. Only moves. Further, in the actuator according to the present invention, since the gap direction of the magnetic circuit is parallel to the tracking direction, the actuator coil does not block the laser beam 5 coming from the optical system, and
Since one suspension leg does not block the laser similarly on the side where the laser comes, the flip-up mirror 6 can be installed inside the actuator.

〔The invention's effect〕

As is clear from the embodiment, according to the present invention, since the optical system of the optical head and the objective lens actuator can be configured on the same plane (on the same substrate), a thin optical head can be realized. By the way, the 16mm thick head can now be reduced to a maximum height of 10mm. Therefore, it is possible to sufficiently contribute to the reduction in the thickness of the entire optical memory disk device. Further, the suspension according to the present invention can be manufactured by integral molding of plastic, and further, the length of the hinge portion,
The frequency characteristic of the lens actuator can be changed by adjusting the hardness. Furthermore, since the plastic is integrally molded, the reproducibility of the characteristics is good, an inexpensive one can be easily obtained, and the cost of the drive can be reduced.

[Brief description of the drawings]

1 is a perspective view of a suspension according to the present invention, FIG. 2 is a plan view of an actuator incorporating the suspension, and FIG. 3 is a side view of the same. FIG. 4 is a schematic configuration diagram of a conventional actuator, and FIG. 5 is a schematic diagram of the vicinity of the actuator of the conventional optical head. DESCRIPTION OF SYMBOLS 1 ... Objective lens 2 ... Lens holder 4, 10 ... Suspension 5 ... Laser beam 6 ... Flip-up mirror 8 ... Magnet 9 ... Yoke

Claims (1)

(57) [Claims] An objective lens for focusing a laser beam on a recording medium, a lens holder for holding the objective lens, and a plurality of hinges coupled to the holder and movable in a focus direction and a track direction. An objective lens actuator, comprising: three link constituent members of a plastic integral molded product; and a magnetic member for moving the objective lens in the focus direction and the track direction.