JPH05120707A - Objective lens driving device - Google Patents

Abstract

PURPOSE:To irradiate a laser beam to a medium recording surface at an accurate angle. CONSTITUTION:This device is provided with an objective lens 7 converging and irradiating the laser beam to a recording medium, a movable member 6 loading the lens 7 and being attached to a base 1 through a track spring 3 and a focus spring 8, a coil driving the member 6 in the direction of a track and a focus by a magnetic circuit consisting of a magnet 9 and a yoke 1c and a base strut 1d adjusting the inclination in the direction of the track of the lens 7 by the track spring 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an objective lens driving device in an optical information recording device.

[0002]

2. Description of the Related Art FIG. 2 is a plan view (a), a side view (b) and a perspective view (c) of an example of a conventional objective lens driving device. The laser light emitted from the semiconductor laser is accurately focused on the medium, and the objective lens is movable in the focus direction, which is the vertical direction to the medium, and the track direction, which is the radial direction, for optical recording and reproduction. It has a support mechanism and a drive mechanism as described above.

As shown in FIG. 2, the movable member 6 for holding the objective lens 7 is connected to the track holder 2 via a focus spring 8. Further, one end of the track spring 3 is fixed to a track holder slit 2a provided in the central portion of the track holder 2 in the vertical direction to form a movable focus assembly. The movable member 6 engages with the base slit 1a provided in the longitudinal direction of the base column 11 standing upright on the base 1 on the other end of the track spring 3 to move the base member 1 from the base 1, for example.
It is set so as to be separated by about mm.

With this configuration, the movable member 6 can be moved in the focus direction by the deflection of the focus spring 8 and can be moved in the track direction by the deflection of the track spring 3, and the driving in the focus direction and the track direction can be performed by the movable member. 6 is performed by the electromagnetic force between the coil provided on the coil 6, the yoke 1c, and the magnet 9 provided on the base 1. The inclination of the objective lens 7 in the track direction with respect to the base mounting surface 1b of the base 1 is determined by the precision of all the parts involved and the precision of assembly.

[0005]

In the above-described conventional objective lens driving device, the jig is used to position the movable member so that the objective lens is perpendicular to the base mounting surface,
Since the track springs were fixed to the slits of the track holder and the base with an adhesive, there were variations in the slit shape.
Due to the shrinkage of the adhesive, the variation of the objective lens mounting hole of the movable member, and the inclination of the objective lens, it is extremely difficult to accurately position the objective lens with respect to the base mounting surface. Had to do.

[0006]

An objective lens driving device of the present invention is an objective lens for condensing and irradiating a recording medium with laser light, and an objective lens mounted on the recording medium and attached to a base via a track spring and a focus spring. A coil for driving the movable member in the track direction and the focus direction by a magnetic circuit including a driving member, a magnet, and a yoke, and a mechanism for adjusting the track direction inclination of the objective lens by the track spring.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a plan view (a), a side view (b) and a cross-sectional view (c) of a track spring mounting portion of the present embodiment.

In this embodiment, as shown in FIG. 1, a movable member 6 holding an objective lens 7 is connected to a track holder 2 via a focus spring 8. Further, one end of the track spring 3 is fixed to a track holder slit 2a provided in the central portion of the track holder 2 in the vertical direction to form a movable focus assembly.

An adjusting slit 10 having a width of, for example, about 2 mm, which is sufficiently wider than the thickness of the tarrac spring 3 at the other end, is provided on the base column 1d at the mounting portion of the track spring 3 of the base 1. The lower ends of the hold plates 4a and 4b holding the track spring 3 sandwiched from both sides are fixed inside the adjustment slit 10, and the upper portions of the hold plates 4a and 4b are sandwiched and attached to the base column 1d by adjustment screws 5a and 5b. By tilting the track spring 3 together with the hold plates 4a and 4b with the adjusting screws 5a and 5b, it is possible to accurately adjust the optical axis tilt of the objective lens 7 with respect to the base mounting surface 1b in the track direction.

[0010]

As described above, according to the present invention, the objective lens for converging and irradiating the recording medium with the laser beam, and the movable member mounted with the objective lens on the base via the track spring and the focus spring are provided. , A coil for driving the starting member in the track direction and the focus direction by a magnetic circuit composed of a magnet and a yoke, and a mechanism for adjusting the inclination of the objective lens in the track direction by a track spring. Since the mounting angle with respect to is accurate, and the laser beam can be irradiated onto the recording surface of the medium at an accurate angle, there is an effect of enhancing the reliability of recording / reproducing information.

[Brief description of drawings]

FIG. 1 is a plan view (a) showing an embodiment of the present invention, a side view (b) and a cross-sectional view of a track spring attachment portion of the present embodiment.

FIG. 2 is a plan view (a), a side view (b) and a perspective view (c) of an example of a conventional objective lens driving device.

[Explanation of symbols]

 1 Base 1a Base Slit 1b Base Mounting Surface 1c Yoke 1d Base Strut 2 Track Holder Slit 3 Track Spring 4a Hold Plate 4b Hold Plate 5a Adjustment Screw 5b Adjustment Screw 6 Movable Member 7 Objective Lens 8 Focus Spring 9 Magnet 10 Adjustment Slit

Claims (2)

[Claims] 1. An objective lens for condensing and irradiating a recording medium with laser light, and a magnetic circuit comprising a driving member mounted with the objective lens on a base via a track spring and a focus spring, a magnet and a yoke. An objective lens driving device comprising: a coil for driving the movable member in a track direction and a focus direction; and a mechanism for adjusting an inclination of the objective lens in the track direction by the track spring. 2. A hold plate for sandwiching the track spring from both sides in a base column connected to the base,
2. The objective lens driving device according to claim 1, wherein the tilt of the objective lens in the track direction is adjusted by a screw that attaches the hold plate to the base column.