JPH0676321A - Actuator mechanism for optical head - Google Patents

Abstract

PURPOSE:To maintain the stroke of large displacement by supporting an objective lens movably in the focusing direction by means of a slider in order to satisfy the recent proposal for providing two optical heads on both the front and the back surfaces of an optical disk in order to simultaneously reproduce on the front and the back surfaces. CONSTITUTION:A lens holder 12 is composed of two leaf springs 13 having elasticity in the tracking direction, an objective lens 11 is fixed on the holder and an actuator main body 14 is fixed on the base plate of the leaf springs 13. That is, the lend 11 is supported movably in the tracking direction by means of the leaf springs 13 and movably in the focusing direction by means of a slider 15. Four tracking coils 16 are fixedly arranged on the back side of the lens holder 12 and two tracking magnets 17 are fixed on the actuator main body 14 while opposing to the coils 16. A pair of focusing coils 18 is fixedly arranged on the main body 14 to provide a magnetic circuit 19 and the lens 11 is moved in the tracking and focusing directions, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator mechanism of an optical head in an optical disk device used as an external storage device of information equipment, for example.

[0002]

2. Description of the Related Art Generally, in an optical head, it is necessary to move an objective lens in a tracking direction and a focusing direction with respect to an optical disk. Conventionally, as such a moving mechanism, for example, there is one as shown in FIG. In the figure, 1 is an objective lens, and this objective lens 1 is fixed to a lens holder 2. The lens holder 2 has elasticity 2 in the tracking direction.
It is supported by the leaf springs 3, 3. Leaf springs 3, 3
The base portion of is supported by a spiral leaf spring 4 which has an elastic force in the focus direction and is fixed to the optical head body side. That is, the objective lens 1 is supported by the leaf springs 3 and 3 so as to be movable in the tracking direction, and is supported by the leaf spring 4 so as to be movable in the focusing direction. Although not shown, a tracking coil is fixedly arranged on the back side of the lens holder 2, and a tracking magnet is arranged so as to face the tracking coil. Then, the objective lens 1 is moved in the tracking direction by the driving force generated between the tracking coil and the tracking magnet in the tracking direction. Further, although not shown, a focus coil is fixedly arranged around the leaf springs 3 and, and a focus magnetic circuit is arranged on the side of the optical head main body so as to face the focus coil. Then, the objective lens 1 is moved in the focus direction by the driving force in the focus direction generated between the focus coil and the focus magnetic circuit.

By the way, recently, an apparatus having two optical heads arranged on both the front and back surfaces of the optical disk has been proposed in order to simultaneously reproduce the front and back surfaces of the optical disk. However, in this case, the distance between the optical heads during reproduction is smaller than the thickness of the cassette that accommodates the optical disc, so that the optical head becomes an obstacle when the cassette is loaded to the target position.

Therefore, in the mechanism shown in FIG. 5, the objective lens 1 is pulled toward the optical head side by the driving force in the focus direction generated between the focus coil and the focus magnetic circuit, and the distance between the optical heads can be loaded. The objective lens 1
With the spiral leaf spring 4 that supports the lens with elastic force in the focus direction, its stroke is at most ± 1 mm.
Since it is only a degree, it is not possible to secure a loading distance.

[0005]

In the optical disk apparatus having the structure in which the two optical heads are arranged on both the front and back surfaces of the optical disk as described above, it is necessary to separate the optical heads from each other to some extent when the cassette is loaded. In the conventional actuator mechanism of the optical head that supports the objective lens so as to be movable in the focus direction by the leaf spring, the stroke required for loading cannot be secured.

Therefore, an object of the present invention is to provide an actuator mechanism of an optical head which can secure a stroke of an objective lens required for loading when loading a cassette.

[0007]

In order to achieve the above-mentioned object, an actuator mechanism of an optical head according to the present invention has the following features.
In an actuator mechanism of an optical head for moving an objective lens and a tracking direction moving mechanism for moving the objective lens in the tracking direction in a focus direction, a slider for movably supporting the objective lens and the tracking direction moving mechanism in a focus direction. ,
An objective lens supported by the slider and a pair of magnetic circuits and coils for generating a driving force for moving the tracking direction moving mechanism in the focus direction are provided.

[0008]

In the present invention, since the objective lens and the like are supported by the slider so as to be movable in the focus direction, it is possible to secure a large displacement stroke in the focus direction. Therefore, it becomes possible to secure the distance between the optical heads so that the cassette can be loaded when the cassette is loaded.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view for explaining the structure of an actuator mechanism of an optical head according to an embodiment of the present invention,
2 is a plan view and FIG. 3 is a front view. In these figures, 11 is an objective lens, and this objective lens 11 is fixed to a lens holder 12. Lens holder 12
Is supported by two leaf springs 13, 13 having an elastic force in the tracking direction. Leaf springs 13, 1
The base of 3 is fixed to the actuator body 14. The actuator body 14 is movably supported in the focus direction by a slider 15 fixed to the optical head body side. That is, the objective lens 11 is supported by the leaf springs 13 so as to be movable in the tracking direction, and is supported by the slider 15 so as to be movable in the focusing direction. Further, the four tracking coils 16 are provided on the back side of the lens holder 12.
Are fixedly arranged, and two tracking magnets 17 are fixedly arranged in the actuator body 14 so as to face the tracking coil 16. Then, the objective lens 11 is moved in the tracking direction by the driving force generated between the tracking coil 16 and the tracking magnet 17 in the tracking direction. Further, the actuator body 14 includes a pair of focus coils 1
8 and 18 are fixedly arranged, and each focus coil 1
Focus magnetic circuits 19 and 19 are fixedly arranged on the optical head main body side so as to oppose to 8. Then, the objective lens 11 is moved in the focus direction by the driving force generated between the focus coil 18 and the focus magnetic circuit 19 in the focus direction.

FIG. 4 is a diagram for explaining a loading operation when the actuator mechanism of the optical head having the above-mentioned structure is applied to an optical disk device for double-sided simultaneous reproduction. In the figure, reference numeral 20 is a cassette in which an optical disk is stored, and reference numerals 21 and 22 are a pair of upper and lower optical heads each having an actuator mechanism according to the present invention. In the loading state shown in FIG. 4A, the objective lens 11 of each of the upper and lower optical heads 21 and 22 is retracted toward the optical head side, and the distance L between the optical heads 21 and 22 is secured to the extent that loading is possible. . From this state, the cassette 20 is loaded as shown in FIG. Then, when the cassette 20 reaches the target position, as shown in FIG.
The objective lenses 11 of Nos. 1 and 22 are pulled out from the optical head side, and the objective lenses 11 of each of the optical heads 21 and 22 are brought close to the cassette 20 to the extent of being reproducible. In addition, when the cassette 20 is taken out, the
This is performed by the reverse operation of (a) to (c).

In the actuator mechanism of the optical head according to the present invention, since the objective lens 11 is supported by the slider 15 so as to be movable in the focus direction, a large displacement stroke in the focus direction can be secured. Therefore, not only the focusing operation but also the cassette retracting operation at the time of loading can be performed by this actuator mechanism.

[0013]

As described above, according to the actuator mechanism of the optical head of the present invention, the objective lens is supported by the slider so as to be movable with respect to the focus direction. The distance can be ensured so that it can be loaded.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining a configuration of an actuator mechanism of an optical head according to an exemplary embodiment of the present invention.

FIG. 2 is a plan view of an actuator mechanism of the optical head shown in FIG.

FIG. 3 is a front view of an actuator mechanism of the optical head of FIG.

FIG. 4 is a diagram for explaining the operation of the present invention.

FIG. 5 is a perspective view for explaining the structure of a conventional actuator mechanism of an optical head.

[Explanation of symbols]

11 ... Objective lens, 12 ... Lens holder, 13 ... Leaf spring, 14 ... Actuator body, 15 ... Slider, 16
... tracking coil, 17 ... tracking magnet, 18 ... focus coil, 19 ... focus magnetic circuit.

Claims (1)

[Claims] 1. An actuator mechanism of an optical head for moving an objective lens and a tracking direction moving mechanism for moving the objective lens in the tracking direction in a focus direction, wherein the objective lens and the tracking direction moving mechanism are movable in the focus direction. An actuator mechanism for an optical head, comprising: a slider supported by the slider, and a magnetic circuit and a coil for generating a driving force for moving an objective lens and a tracking direction moving mechanism supported by the slider in a focus direction.