JPH03273532A - Objective lens driving device - Google Patents

Abstract

PURPOSE:To improve the reliability on the recording and reproducing of information to and from a recording medium without adversely affecting the driving of an objective lens by integrally molding a focusing coil and a tack coil together with a bobbin for holding the objective lens. CONSTITUTION:This driving device is provided with the objective lens which condenses a laser beam to the recording medium, the tack coil 3 which moves the objective lens in the track direction with respect to the objective lens when energized, the focusing coil 2 which moves the objective lens in the focusing direction with respect to the recording medium when energized, and the bobbin member 1 which has the holding part for holding the objective lens and is formed by integral molding so as to fix the tack coil 3 and the focusing coil 2 to prescribed positions. The exact positioning of the tack coil 3 is executed in this way and the reliability on the recording and reproducing of the information to and from the recording medium is improved without adversely affecting the driving of the objective lens in the focusing direction and the track direction.

Description

TECHNICAL FIELD The present invention relates to an objective lens driving device, and more particularly to an objective lens driving device for an optical information recording device.

BACKGROUND ART Conventionally, in optical information recording devices, an objective lens that accurately focuses laser light emitted from a semiconductor laser onto a recording medium for optical recording and reproduction is mounted perpendicular to the recording medium. A support mechanism and a drive mechanism are provided to support and drive the recording medium so as to be movable in the focus direction and the track direction, which is the radial direction of the recording medium.

For this support mechanism and drive mechanism, a support method using a spring or the like and a drive method using electromagnetic force using a magnet and a coil are generally used.

That is, as shown in FIGS. 3 to 5, the objective lens (
The focus coil 2 is wound around a bobbin 5 that has a lens attachment hole 53 for attaching a lens (not shown), and the track coils 3 and 4 wound in advance are placed at a predetermined position on the focus coil 2 using a jig (not shown). It was stuck after positioning (see Figures 3 and 4).

As described above, the movable part formed by the bobbin 5, the focus coil 2, and the track coil 3.4 is passed through the yoke 62.63 on the base 61 through the yoke through hole 51.52 of the bobbin 5. Attach to the fixed part 6.

Here, since magnets 7 and 8 are attached to the fixed part 6 so as to face the yokes 62 and 63, the movable part (objective lens) is moved in the focus direction (direction of arrow A) by energizing the focus coil 2. ), and by energizing the track coil 3.4, the movable part (objective lens) was moved in the track direction (direction of arrow B).

In such a conventional optical information recording device, the track coils 3 and 4 are crimped and positioned on the focus coil 2 wound around the bobbin 5 using a jig, and then the track coils 3 and 4 are attached to the focus coil 2. Since it is fixed, the focus coil 2 wound around the bobbin 5
When the outer circumference of the focus coil 2 becomes irregular, that is, the focus coil 2
If unevenness occurs on the outer periphery of the track coil 3.4, it becomes impossible to accurately position the track coil 3.4 with respect to the bobbin 5.

If the second track coil 3.4 is not positioned accurately, the magnitude and direction of the driving force generated by the magnetic field and current will vary, making it impossible to accurately drive the movable part in the track direction. A problem arises in that the driving of the movable part in the focus direction is also adversely affected.

OBJECTS OF THE INVENTION The present invention has been made to eliminate the problems of the conventional ones as described above, and it is possible to accurately position the track coil, and it does not adversely affect the driving of the objective lens in the focus direction and the track direction. It is an object of the present invention to provide a format lens driving device that can improve the reliability of recording and reproducing information on a recording medium without causing any damage.

Structure of the Invention The objective lens driving device of the present invention includes: an objective lens that focuses a laser beam onto a recording medium; a track coil that moves the objective lens in a track direction with respect to the recording medium when energized; A focus coil that moves the objective lens in a focus direction with respect to the recording medium by being energized, and a holding part that holds the objective lens, and fixes the track coil and the focus coil at predetermined positions. The bobbin member is formed of an integral oval shape.

Embodiment Next, an embodiment of the present invention will be described with reference to the drawings.

1 and 2 are perspective views of one embodiment of the present invention. FIG. 1 is a perspective view after molding, and FIG. 2 is a perspective view before molding.

In these figures, a focus coil 2 and a track coil 3 are positioned by a mold (not shown) when the bobbin 1 is molded, and are then integrally molded with a resin together with the bobbin 1. Thereby, the positioning of the track coil 3 can be performed accurately.

The bobbin 1 molded as described above is supported by a spring or the like (not shown) with respect to the fixing member 6 shown in FIG. Then, the track coils 3 are energized to move in the track direction (direction of arrow B).

That is, the magnet 7.8 is attached to the yoke 62 in the fixed part 6.
．． 63, respectively, and are fixed oppositely to the yokes 62 and 63.
3 penetrates through the yoke through holes 11° and 12 of the bobbin 1, and the focus coil 2 and track coils 3 and 4 are arranged in the gap between the magnet 7.8 and the yoke 62.63. By energizing the track coil 34, a driving force for the bobbin 1 is generated by electromagnetic action between the focus coil 2, track coils 3 and 4, and the magnet 7.8.

Using this driving force, an objective lens (not shown) attached to the lens attachment hole 13 of the bobbin is driven in the focus direction and the track direction.

In this way, the focus coil 2 for driving the objective lens in the focus direction and the track coils 3 and 4 for driving the objective lens in the track direction are integrally molded together with the bobbin 1 that holds the objective lens. By doing so, it is possible to accurately position the track coil 3.4.

Thereby, the objective lens held by the bobbin 1 can be accurately driven in the focus direction and the track direction, and the laser beam emitted from the semiconductor laser (not shown) can be directed onto the recording medium (not shown). Irradiation can be performed accurately.

Therefore, the reliability of recording and reproducing information on the recording medium can be improved.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, as described above, a focus coil for moving the objective lens in the focus direction and a track coil for moving the objective lens in the track direction are used to hold the objective lens. By integrally molding the track coil with the bobbin, it is possible to accurately position the track coil, without adversely affecting the driving of the objective lens in the focus direction and the track direction. This has the effect of improving reliability.

[Brief explanation of drawings]

1 and 2 are perspective views of one embodiment of the present invention;
5 is a perspective view of a conventional example. Explanation of symbols of main parts 1...Bobbin 2...Focus coil 3.4...Track coil

Claims (1)

[Claims] (1) an objective lens that focuses laser light on a recording medium; and a track coil that moves the objective lens in a track direction with respect to the recording medium when energized;
a focus coil that moves the objective lens in a focus direction with respect to the recording medium by being energized;
An objective lens driving device comprising: a holding portion for holding the objective lens; and a bobbin member formed by integral molding so as to fix the track coil and the focus coil at predetermined positions.