JPH05266503A - Optical head - Google Patents

Abstract

PURPOSE:To stabilize the moving performance of an objective lens and to improve manufacturing performance by constituting a pair of arm parts connecting a first and a second respective attaching parts with two sheets of elastic supporting plates integrally molded. CONSTITUTION:The elastic supporting plate 20 is provided with an attaching part 20A fixed to a lens holder 5, the attaching part 20B formed at a certain gap to the former and fixed to tire rising wall part 10A of a base 10 provided in the vicinity of the disposing position of the holder 5, a pair of the arm parts 20c. An elastic supporting means 6 is made a shape similar to a parallel four wires supporting system since the holder 5 and the base 10 are connected with four fine arm parts 20c by providing two supporting plates 20 in a parallel state. Then the holder 5 and an objective lens 4 are moved in the directions of focusing and tracking corresponding to a relation between the magnetic field of a magnet 11 and magnetic flux generated by making flow current through a focus control coil 7 and a track control coil 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head of an optical information storage device such as an optical disk device, and more particularly to an optical head having an improved support structure of an objective lens for focusing a light beam on an optical information storage medium.

[0002]

2. Description of the Related Art Generally, an optical head of an optical information storage device is
A parallel beam of a laser beam emitted from a semiconductor laser and guided through an optical system such as a collimating lens and a rising mirror is focused on an optical disc which is an optical information storage medium, or a laser beam reflected from the optical disc. Has an objective lens for converting the beam into a parallel beam again.

Further, the objective lens is held by a lens holder as a lens holder, and the lens holder is movably supported by elastic supporting means. Then, the direction in which the optical disc 5 is moved toward and away from the optical disc 5, that is, the focus control direction, and the radial direction of the optical disc,
That is, it can be moved in the tracking direction.

As the elastic supporting means in the conventional optical head, a structure in which it is supported by four parallel wires or a structure in which it is supported by two parallel leaf springs to which a hinge member is connected is known. ..

However, although the former objective lens supported by four wires is stable in terms of performance, it is necessary to accurately fix the four wires so that they are parallel to each other. It is very difficult to assemble and adjust. In addition, the structure for securely fixing the four wires to the objective lens and the base becomes complicated and the cost is inevitably increased.

In the latter structure having two parallel leaf springs supported by hinges, it is relatively easy to maintain the parallel relationship between the two parallel leaf springs. The members must be accurately connected, which is extremely difficult and costly. Further, since the objective lens moves in the tracking direction by rotating about the hinge member, there is a problem in that the influence of jitter or the like does not appear on the signal for accurate recording.

[0007]

As described above, in the conventional optical head, the elastic supporting means for movably supporting the objective lens has a large number of parts and the structure is complicated, so that the assembling workability is poor and the cost is low. However, there is a problem in that the one using parallel leaf springs has poor stability in terms of performance.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical head capable of stabilizing the movement performance of an objective lens, reducing the cost, and improving the manufacturability. ..

[0009]

As a first means for solving the above problems, the present invention provides an objective lens which is held by a lens holder and focuses a light beam on an optical information storage medium, and the objective lens. It comprises elastic supporting means for movably supporting the held lens holding body, and lens driving means for moving the lens holding body movably supported by the elastic supporting means in the focus direction and the tracking direction. In the optical head, the elastic supporting means is provided with a first mounting portion fixed to the lens holding body, and an arrangement of the lens holding body formed at a certain distance from the first mounting portion. A second attachment portion fixed to a support attachment member provided near the installation position;
And a pair of arm portions connecting the second mounting portion and the mounting portion are integrally formed by two elastic support plates. As a second means, the elastic support plate has an arm portion provided with a hinge portion formed of a bent portion or a cutout portion.

[0010]

According to the optical head of the first means, the elastic support means for movably supporting the lens holding body holding the objective lens is provided with the first mounting portion fixed to the lens holding body, and the first attaching portion. A second mounting portion which is formed at a certain distance from the mounting portion and is fixed to a supporting member mounted member such as a base provided in the vicinity of the disposition position of the lens holding body; It is configured by two elastic support plates integrally formed with a pair of arm portions that connect the mounting portion and the second mounting portion. This makes it possible to adopt a structure similar to that of the four parallel wire support system, which not only stabilizes the performance, but also makes the elastic support plate with high precision by etching the leaf spring. Moreover, since the number of parts is small, assembly workability can be improved and cost can be reduced.

Further, according to the second means, since the arm portion of the elastic support plate is provided with the hinge portion composed of the bent portion or the notch portion, the structure becomes easy to move in a direction other than the focus direction, which is more stable in performance. It becomes possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

As shown in FIGS. 1 and 2, an optical pickup 1 as an optical head is emitted from a semiconductor laser and guided through an optical system such as a collimating lens (neither is shown) and a rising mirror 2. It has an objective lens 4 for focusing a parallel beam of a laser beam L as a light beam toward an optical disc 3 as an optical information storage medium and for converting the laser beam L reflected from the optical disc 3 into a parallel beam again. There is.

The objective lens 4 is held by a lens holder 5 as a lens holder, and the lens holder 5 is movably supported by an elastic supporting means 6 which will be described later, and the focus of the optical disk 3 is maintained. It is movable in the control direction (Z-axis direction) and the track control direction of the optical disc 3 (X-axis direction).

Around the lens holder 5, a pair of focus control coils 7 for moving the lens holder 5 holding the objective lens 4 in the Z-axis direction and the lens holder 5 holding the objective lens 4 are arranged on the X-axis. A pair of track control coils 8, 8 for moving in the direction is arranged.

The focus control coil 7 is a hollow coil and is fixed in close contact with the lens holder 5. The track control coils 8 and 8 are flat coils, and the focus control coil 7 is a flat coil.
Is located outside of.

The base 10 has magnets 11 and 11 for providing a magnetic field in a desired direction toward the focus control coil 7 and the track control coils 8 and 8.
And the yokes 12 and 12 are respectively arranged,
A lens driving unit 15 is configured to move the lens holder 5 movably supported by the elastic supporting unit 6 in the focus direction and the tracking direction.

The optical pickup 1 having the above-described structure guides the laser beam L reflected by the optical disc 3 to a focusing detector and a tracking detector (not shown) (not shown).
Is fixed on a chassis (not shown) having a.
The chassis is moved in the track control direction, that is, in the radial direction of the optical disc 3 by a chassis moving means composed of a linear motor (not shown) that constitutes an access mechanism.

On the other hand, the light guided to the focusing detector is used for focusing to generate a difference signal from the output signals from the cells of the focusing detector which are multi-divided according to the distance relationship between the optical disc 3 and the objective lens 4. The focus error signal is generated by the differential detector and is used to move the focusing magnetic circuit of the lens driving means 15.

Similarly, the light guided to the tracking detector is used to move the tracking magnetic circuit of the lens driving means 15 due to the track error amount being a track error signal by the tracking differential detector.

The elastic supporting means 6 includes two elastic supporting plates 20 and 20 formed as shown in FIG.
The lens holder 5 is supported in parallel with the lens holder 5.

The elastic support plate 20 includes a first mounting portion 20A fixed to the lens holder 5 and the first mounting portion 20A.
The lens holder 5 is formed with a certain distance to
Second mounting portion 20B fixed to the rising wall portion 10A as a support member mounting member of the base 10 provided near the disposition position of the base 10, and the first mounting portion 20A and the second mounting portion 20B. It is made up of a pair of arm portions 20C, 20C that connect the and.

The elastic support means 6 includes two elastic support plates 20,
By providing 20 parallel to each other, the parallelism is achieved in that the lens holder 5 that is the movable member and the base 10 that is the fixed member are connected to each other by four thin arms 20C.
It has a shape similar to this wire support method.

Further, since the arm portion 20C is provided with the hinge portion 20D composed of an arcuate bent portion, the structure is such that the arm portion 20C can be easily moved in a direction other than the focus direction. As a result, it is possible to solve the drawback of the parallel leaf spring support system that the parallel leaf spring alone does not move in the tracking direction.

Since the elastic supporting plates 20, 20 can be easily processed by etching or the like, the two arm portions 20C, 2
The structure of 0C can be set freely and, by integrating, the two arm portions 20C and 20C do not need to adjust their mounting angles. Also, when the lens holder 5 is fixed to the first mounting portion 20A, the lens holder 5 can be fixed in a wide area by adhesion or the like, and can be fixed easily and surely. Similarly, when fixing the base 10 to the second mounting portion 20B, the base 10 can be fixed in a wide area by adhesion or the like, and can be fixed easily and surely. Furthermore, when the moving characteristics of the objective lens 4 are improved, it can be processed by etching or the like, so that a subtle structure change is possible.

Therefore, the lens holder 5 supported by the elastic support plates 20, 20 and the objective lens 4 fixed to the lens holder 5 can apply current to the magnetic field of the magnet 11, the focus control coil 7 and the track control coil 8. The magnetic field is moved in the focusing direction and the tracking direction in accordance with the relationship of the magnetic flux generated by.

FIG. 4 shows a state in which the lens holder 5 and the objective lens 4 fixed to the lens holder 5 are moved in the focusing direction (in the figure, moved upward).
Is a lens holder 5 and an objective lens 4 fixed to the lens holder 5.
Shows a state in which is moved in the tracking direction.

In this way, even if the optical disk 3 has a surface wobbling, the objective lens 4 moves up and down to obtain an accurate focused spot. Further, by following the eccentricity of the optical disk 3 and moving in the radial direction, the objective lens 1 faces the guide groove in which a signal source called a pit is formed. As a result, good information processing can be performed.

In the above-described embodiment, by making the width of the arm portions 20C, 20C of the elastic support plates 20, 20 in the tracking direction small, it is possible to move also in the tracking direction as shown in FIG. However, in the above-described embodiment, the arm portions 20C, 20C are formed with the hinge portion 20D formed of an arcuate bent portion, so that the arm portions 20C, 20C are more easily moved.

Further, the hinge portion 20D is not limited to an arcuate bent portion, but may be a V-shaped bent portion or another shape as shown in FIG. 6, for example. Also, for example, in FIG.
Alternatively, the arm portion 20C may be formed of a plurality of supporting portions, and a part of the supporting portion may be cut out as shown in FIG.

The point is that any shape may be used as long as it can smoothly move in the tracking direction.
It is also possible to add some shape to the shape of the support so that it can be used. This can also be easily done by processing the leaf spring by etching or the like. In addition, it goes without saying that the present invention can be variously modified without departing from the scope of the invention.

[0032]

As described above, the present invention has the following effects.

That is, according to the optical head of the first aspect, the elastic supporting means for movably supporting the lens holding body holding the objective lens is provided with the first mounting portion fixed to the lens holding body. A second member which is formed at a certain distance from the first mounting portion and is fixed to a supporting member mounted member such as a base provided in the vicinity of the arrangement position of the lens holding member.
And the pair of arm portions connecting the first mounting portion and the second mounting portion are integrally molded, and are configured by two elastic support plates. This makes it possible to adopt a structure similar to that of the four parallel wire support system, which not only stabilizes the performance, but also makes the elastic support plate with high precision by etching the leaf spring. In addition, since the number of parts is small, the assembly workability can be improved and the cost can be reduced.

According to the optical head of the second aspect, in addition to the above effects, since the arm portion of the elastic support plate is provided with the hinge portion formed of the bent portion or the cutout portion, it is easy to move in a direction other than the focus direction. The structure is provided, and it is possible to obtain a more stable performance.

As described above, according to the present invention, it is possible to provide an optical head capable of stabilizing the moving performance of the objective lens, reducing the cost, and improving the manufacturability.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of an objective lens peripheral portion according to an embodiment of the present invention.

FIG. 2 is a side view of the portion shown in FIG.

FIG. 3 is a plan view of an elastic support plate which is a main part.

FIG. 4 is an explanatory view showing a moving state of the apparatus shown in FIG. 1 in a focusing direction.

5 is an explanatory diagram showing a moving state of the device shown in FIG. 1 in a tracking direction.

FIG. 6 is a plan view showing a first other embodiment of an elastic support plate which is a main part.

FIG. 7 is a plan view showing a second other embodiment of the elastic support plate which is the main part.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical pickup (optical head), 3 ... Optical disk (optical information storage medium), 4 ... Objective lens, 5 ... Lens holder (lens holder), 6 ... Elastic support means, 7 ... Focus control coil, 8 ... Track control. Coil, 10 ... Base, 10A ... Standing wall portion (support member attached member), 11 ...
Magnet, 12 ... Yoke, 15 ... Lens driving means, 2
0 ... Elastic support plate, 20A ... First mounting portion, 20B ... Second
Mounting portion, 20C ... arm portion, 20D ... hinge portion, L ...
Laser beam (light beam).

Claims (2)

[Claims] 1. An objective lens, which is held by a lens holder and focuses a light beam on an optical information storage medium, elastic supporting means for movably supporting the lens holder holding the objective lens, and this elastic support. And a lens driving means for moving the lens holder movably supported by means in a focus direction and a tracking direction, wherein the elastic support means is fixed to the lens holder. A first mounting portion, and a second mounting portion, which is formed at a certain distance from the first mounting portion and is fixed to a support member mounted member provided in the vicinity of the arrangement position of the lens holder. Mounting part of
An optical head comprising two elastic support plates integrally formed with a pair of arm portions connecting the first mounting portion and the second mounting portion. 2. An objective lens, which is held by a lens holder and focuses a light beam on an optical information storage medium, elastic supporting means for movably supporting the lens holder holding the objective lens, and this elastic support. And a lens driving means for moving the lens holder movably supported by means in a focus direction and a tracking direction, wherein the elastic support means is fixed to the lens holder. A first mounting portion, and a second mounting portion, which is formed at a certain distance from the first mounting portion and is fixed to a support member mounted member provided in the vicinity of the arrangement position of the lens holder. Mounting part of
It is composed of two elastic support plates which are integrally formed with a pair of arm portions which connect the first mounting portion and the second mounting portion and which are provided with a hinge portion composed of a bent portion or a cutout portion. An optical head characterized by.