JPS6282522A - Optical system driver - Google Patents

Abstract

PURPOSE:To improve the driving sensitivity of an optical system driver by dividing a coil into the outer and inner circumferential parts of an optical system holder in order to improve the heat radiation effect of the coil and also to increase the allowable current value. CONSTITUTION:When a coil which drives an objective lens holder 2 toward its optical axis is laminated in four layers at a flange part of the holder 2, the winding job is divided into the outer and inner parts of the holder 2. In this case, the coil is divided into two layers 8a and 8b of the outer circumference and layers 8c and 8d of the inner circumference respectively. Thus the number of coil layers is set equal to that of a conventional case in all. Under such conditions, the effective length crossing a magnetic field and the number of coil turns are equal to each other5 among those divided coils together with the same drive current as long as the same magnetic circuit is used. Thus the driving power of the holder 2 is kept constant. The coil surface is directly exposed to outside at both layers 8a and 8d owing to the lamination of coils and therefore the heat of the coil is radiated into the air. While the coil surface has a direct contact with the holder 2 at both layers 8b and 8c and therefore the heat of the coil is radiated to the holder 2 itself.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical system driving device, and in particular has a coil wound in a direction perpendicular to the optical axis of an optical system, and a coil wound in a direction perpendicular to the optical axis of the optical system. The present invention relates to an optical system drive device having a movable optical system holder and a magnetic circuit that forms a magnetic field in the coil.

[Prior art]

Conventionally, this type of optical system driving device has a focus control function to drive and control the optical system in the optical axis direction, and a tracking control function to drive and control the optical system in a direction perpendicular to the optical axis direction. For this purpose, the optical system holder has a driving coil in the optical axis direction and a driving coil in the direction perpendicular to the optical axis direction.

Fig. 3 is a partial longitudinal sectional view of a conventional optical system holder.
2 is an optical system holder, and 8 is a driving coil in the optical axis direction. As shown in the figure, seven lunges were provided on the outer periphery of the optical system holder, and a coil 8 was wound in a laminated manner.

[Problem that the invention seeks to solve]

However, in the conventional optical system drive device described above,
When driving the optical system in the direction of the optical axis, in order to increase the drive sensitivity, if an overcurrent is applied to the coil, the insulation layer of the coil will be destroyed by the heat in the inner layer of the laminated part, which has poor heat dissipation effect due to the coil's own heat generation. There was a problem in that adjacent coils would short-circuit each other, making normal driving impossible.

The purpose of the present invention is to improve the heat dissipation effect of the coil, and at the same time
The purpose is to increase the permissible current value of the coil and improve drive sensitivity.

[Means for solving problems]

The above problem requires an optical system holder that has a coil wound in a direction perpendicular to the optical axis of the optical system and is movable in the optical axis direction, and a magnetic circuit that forms a magnetic field in the coil. In an optical system drive device having.

The problem is solved by the optical system driving device of the present invention, characterized in that the coil is divided into an outer circumferential portion and an inner circumferential portion of the optical system holder.

[For production]

The optical system drive device of the present invention separates the coil into the outer circumferential portion and the inner circumferential portion of the optical system holder, thereby reducing the contact between the coil and the optical system holder compared to a case where the coil is wound only on the outer circumferential portion. Since the area can be increased and the exposed area of the coil to the air can be increased, the heat dissipation effect can be significantly improved.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail using the drawings.

In addition, as an optical system driving device of the present invention,
9'J KJ knee ri a @ 'k n 5° tctt FIG. 9 is an exploded perspective view of one embodiment of the objective lens driving device according to the present invention. Reference numeral 1 is an objective lens for condensing radar light onto a recording medium, and 9 is an objective lens barrel for protecting and fixing the objective lens. 2 is an objective lens holder, and 3 is a bearing for moving the objective lens holder in the rotational direction and axial direction about the support shaft 13. 4. ．． Reference numeral 5 denotes a coil, and the objective lens holder 2
is driven in the rotational direction around the support shaft 13. 6,
7 is connected to the center point 10ael1m of the spiral spring 10.11 by a pin installed in the notch of the objective lens holder. Reference numeral 8 denotes a coil that drives the objective lens holder 2 in the axial direction of the support shaft 13 by the interaction between the magnetic field generated by passing a current through the coil and permanent magnets 18 and 19 provided on the base 20 side. Reference numeral 12 denotes a neutral point holder for the objective lens l attached to the objective lens holder 2, with spiral springs 1 at both ends.
0 and 11 are attached, insert the circular hole 12m into the support shaft 13 attached to the base 20, and insert the circular hole 12b,
12c to the fixing pins 14° [15, respectively. 211 “vf-light”?
3*17:/-e” incidence 276 through 1 hole 1.

FIG. 2 is a partial vertical sectional view of the objective lens [1 holder] of the objective lens driving device.

In FIG. 2, the optical axis direction driving coil of the objective lens holder 20 is connected to the flange portion of the objective lens holder 7.
In the case of laminating four layers, the wires are wound separately on the outer circumference and the inner circumference of the objective lens holder, and the coils are divided into layers 8a, 8b on the outer circumference, 8c and 8d on the i circumference, respectively. At this time, if the total number of layers in the coil is the same as in the conventional example shown in Fig. 3, and the same magnetic circuit 1:1' is used, the effective length of the coil across the magnetic field and the number of filters are If they are equal and the driving currents are equal, the driving forces of the objective lens holder are the same.

; By stacking the coils as described above, each fill'・ff, (71mM*[e*flJKJt1L<
IIL: l-1゜1' The coil surface of the coil layer 8 and 8d is directly exposed to the outside.
Since the coil layers 8b and 8c are in direct contact with the objective lens holder 2, the heat generated by the coils is radiated into the air. Heat is radiated @Here, if a material with good thermal conductivity such as AA is used for the objective lens holder,
Furthermore, the heat dissipation effect is improved.

〔Effect of the invention〕

As explained above, according to the optical system drive device of the present invention,
By dividing the optical axis direction drive coil into the outer circumference and inner circumference of the optical system holder, the heat dissipation effect of the heat generated in the coil is significantly enhanced, and the allowable current value flowing through the coil is relatively increased. This has the effect of improving drive sensitivity.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of one embodiment of an objective lens driving device according to the present invention. FIG. 2 is a partial vertical sectional view of the objective lens holder of the objective lens driving device. FIG. 3 is a partial longitudinal sectional view of an optical system holder of a conventional optical system driving device. l...Objective lens, 2...Objective lens holder, 3.
・・Bearing, 4+5p8t8at8b, 8c+8d・=r
Ile, 16, 17, 18. 19... Permanent magnet, 20.
...base.

Claims (1)

[Claims] It has a coil wound in a direction perpendicular to the optical axis of the optical system,
and an optical system drive device having an optical system holder that is movable in the optical axis direction and a magnetic circuit that forms a magnetic field in the coil, wherein the coil is divided into an outer peripheral part and an inner peripheral part of the optical system holder. An optical system drive device characterized by: