JPS6154048A - Objective lens supporting device of optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To correct easily the inclination of a lens optical axis and to support the lens with high accuracy by providing a fine adjusting means on one of flat springs for supporting a lens holder and rotating and changing the lens holder. CONSTITUTION:The lens holder 3 of an objective lens 1 is supported by flat springs 4A and 4B and flat springs 14A and 14B so that in each pair the springs are coupled to be orthogonal to each other. The flat spring 14A is equipped with a tool hole 15 and a fine adjusting means which is positioned at the hole 15 and composed of a tool groove 16 having a V-shaped bottom larger than the hole 15. In order to adjust the lens 1 in an Y direction under this constitution, a machine screw 13A is loosened, and a bar-like tool is inserted into the tool hole 15 to move it vertically. The holder 3 is rotated to adjust the inclination in the Y direction, and the machine screw 13A' is tightened. As a result, the inclination of an optical axis, which needs about one minute for fixing, can be easily corrected and the lens can be supported with high accuracy.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to an optical recording and reproducing apparatus that optically records or reproduces music by projecting a light beam for recording or reproducing music onto a rotating recording medium. The present invention relates to an objective lens support device.

[Background of the invention]

In recent years, with advances in laser technology, disk-shaped recording media (hereinafter referred to as "optical disks") that rotate laser light beams have become available.

) optical recording (reproduction) device (hereinafter simply referred to as "
``optical memory device.'' ) have been put into practical use. One of the features of this optical memory device is its extremely high information recording density, but in order to achieve this, a light beam must be focused on the optical disk to create a minute optical spot with a diameter of approximately 1 μm or less. It is necessary to form the To do this, it is necessary to project and focus the light beam onto the optical disk using an objective lens with a large numerical aperture (N, A).

When using an objective lens with a large numerical aperture, the optical axis of the objective lens must be supported perpendicularly to the projection surface of the optical disc with extremely high precision. This is because the larger the numerical aperture, the wider the convergence angle of the light beam, which causes aberrations in the light beam due to the transparent protective layer of the optical disc, making it extremely difficult to obtain a light spot with a diameter of about 1 μm. be.

On the other hand, in optical memory devices, an automatic system that displaces an objective lens in the optical axis direction is used to accurately focus a minute light spot on a guide groove that serves as a reference for information tracks recorded spirally or concentrically on an optical disk. Relative positional deviation between the focusing mechanism, the light spot, and the guide groove (
An automatic tracking mechanism for correcting the deviation of the optical disk in the radial direction (-\) is provided, and tracking and focusing of the objective 1/lens are automatically performed. A tracking mechanism that performs optical tracking is also known, but as one that performs tracking and focusing relatively easily, an objective 1/lens that is movable in the optical axis direction of the objective lens and in a direction perpendicular thereto is used. Various objective 1/lens drive devices have been proposed and are known, which support this and perform both focusing and tracking.

Among the known objective lens drive devices, an objective lens holding frame is supported by two sets of parallel leaf springs disposed perpendicularly to each other so that the objective lens can be displaced accurately and smoothly. An objective lens support device configured as shown in FIG.

However, in this disclosed objective lens support device, in order to install the objective lens in the correct position without tilting, a filler is injected into the joint between the objective lens holding frame and the parallel leaf spring. Since it is configured to connect the two, a special jig is required for assembly, and since it is necessary to wait until the filler hardens, a large number of jigs are required for mass production. If dust or the like gets between the lens and the objective lens, the accuracy will decrease, and the objective lens may become scratched or dirty.

[Purpose of the invention]

The present invention solves the drawbacks of the conventional objective lens support device using parallel plate spring support, and provides an objective lens support device that can easily correct the inclination of the objective lens, has a simple configuration, and has high accuracy. purpose.

[Summary of the invention]

In order to achieve the above object, the present invention provides a first parallel plate that supports a 1/lens holder that holds an objective lens so as to be movable in a focusing direction and a tracking direction, and that is connected so that the deflection directions are perpendicular to each other. Among the spring and the second parallel plate spring, one end of one of the two parallel spring plates constituting the 2,000th row spring whose one end is fixed to the fixed member is connected to the other spring plate. , the second parallel plate is provided with a fine adjustment means for relatively displacing the second plate spring in a direction perpendicular to the direction of deflection, and the second parallel plate is generated when one end of one of the spring plates is relatively displaced with respect to the other spring plate. The technical point is to configure the lens holder fixed to one end of the first parallel plate spring to be rotationally displaced by the fine adjustment means in the direction of the torsion of the spring.

〔Example〕

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

FIG. 1 is a front view showing an embodiment of the present invention, FIG. 2 is a plan view of the embodiment of FIG. 1, and FIG. 3 is a sectional view taken along line AA in FIG. 1.

In FIG. 3, an objective lens 1 for focusing a 1/-the light beam onto an optical disk fx shown is held in a lens holder 3 via a lens frame 2. In FIG. The inside of the lens holder 3 is formed into a cavity, and an opening 3A is provided at the bottom to guide the laser beam to the objective lens IVc. At the upper and lower parts of this lens holder 3, there are protrusions 3B and 3 that protrude left and right, respectively, in FIG.
C is formed, and the upper surface of the upper protrusion 3B and the lower protrusion 3C
On the lower surface of the frame is a frame-shaped spring plate 4A as shown in FIG.

One end of 4B is fixed with machine screws 5A and 5B. Further, at the other ends of the two spring plates 4A and 4B, as shown in FIG. 1, a relay member 6 is attached with a machine screw 5A.

5B, and the lens holder 3, two spring plates 4A and 4B, and the relay member 6 form a parallelogram. These two frame-shaped spring plates 4A and 4B
This constitutes a first parallel plate spring that supports the lens holder 3 so as to be movable in the optical axis direction of the objective lens l.

The middle part of the lens holder 3 is formed so that the cross section perpendicular to the optical axis is approximately square.A focusing coil 7 is wound around the outer periphery of the middle part as shown in FIG. Two tracking coils 8A forming a
, 8B are attached and fixed. The focusing coil 7 and the tracking coils BA, BB are fixedly mounted on the plywood 10 and two permanent magnets 9A, 9B are provided to sandwich the coils 7.8A, 8B from the inside and outside. 2 (1) supporting the permanent magnets 9A and 9B, respectively.
Together with the yokes 11 and 12, they form a linear motor that moves the 1/2 lens holder 3 vertically and horizontally in FIG.

The two yokes 11 and 12 form an aperture 1 through which the laser beam passes.
As shown in FIG. 2, each yoke 11 .
12 has a U-shaped cross section as shown in FIG. One rising portion 1 of each yoke 11 and 12
Permanent magnets 9A and 9B are fixed to 1A and 12A, and the other rising portions 11B and 12B are 1A and 12A, as shown in FIG.
The rectangular holes 3D and 3D' provided in the lens holder 3 are provided so as to penetrate through the rectangular holes 3D and 3D'. The rectangular tracking coils 8A, 8B are placed in the respective magnetic fields between the rising portion 11B of one yoke 11 and the permanent magnet 9A and between the rising portion 12B of the other yoke 12 and the permanent magnet 9B. The short side of (the part perpendicular to the paper in Figure 2) is placed, and 2
The long side portions of the tracking coils 8A and 8B (the portion perpendicular to the plane of the paper in FIG. 3) are placed outside the magnetic field between the magnets 9A and 9BO (see FIG. 2).

On the other hand, spring plates 14A are provided on both sides of the relay member 60, respectively.
, 14B are fixed by machine screws 13A, 13B, and the spring plate 14A.

The other end of 14B is machine screwed 13A' on both sides of one rising portion 12A of yoke 12 as shown in FIG.

13B'. One rising portion 12A of this yoke 12 and two spring plates 14A.

14B and the relay member 6 form a parallelogram as shown in FIG. The two spring plates 14A,
14B constitutes a second parallel leaf spring that supports the 1/lens holder 3 so that it can be displaced in a direction perpendicular to the optical axis.

FIG. 4 shows two spring plates 14 constituting the second parallel plate spring.
FIG. 5 is an enlarged front view of the joint between one spring plate 14A of A and 14B and one rising portion 12A of the yoke 12;
The figure is a sectional view taken along the line BB in FIG. 4, and FIG. 6 is a plan view of the leaf spring joint shown in FIG. 4, viewed from above.

In FIG. 4, one end of the spring plate 14A has two small screws 13A' in between, and the spring plate 14B also has a screw.
On both sides of the rising portion 12A of the yoke 12, the tool hole 15 is formed and the spring plates 14A, 14B are attached.
As shown in FIG. 5, a tool groove 16 that is larger than the tool hole 15 (and has a V-shaped bottom) is provided at a position corresponding to the tool hole 15. Also, a permanent magnet 9BVi, whose side surface is shown in FIG. As shown, it is formed to have a width slightly wider than the width of the rising portion 12A of the yoke 12 so as to slightly protrude from the side surface of the rising portion 12A.
a (see FIG. 6) comes into contact with the permanent magnet 98, so that the mounting position in the left and right direction in FIG. 4 is restricted.

Note that the hole in the spring plate ±4A into which the machine screw 13A' is inserted is formed into a hole with a diameter somewhat larger than that of a normal hole, or an elliptical hole that is long in the vertical direction in FIG.
It is tightened and fixed by machine screw 138' via washer 17.

Since the embodiment shown in FIG. 1 is constructed as described above, the lens holder 3 holding the objective lens l is supported by the relay member 6 via the first parallel leaf springs 4A and 4B, and the relay member 6 is , is supported by the rising portion 12A of the yoke 12 via the second parallel plate springs 14A, 14B. 1
In order to minimize the laser spot image, the objective lens 1 must be assembled so that its optical axis is perpendicular to the base plate 10Vc, which is parallel to the surface of the optical disk. However, as described above, the objective lens IH1 has two sets of first parallel plate springs 4A, 4B and second parallel plate springs 14A, 14 that are orthogonal to each other.
Since the optical axis is supported through the parallel plate springs 14A and 14B in the X direction parallel to the second parallel leaf springs 14A and 14B in FIG. This causes an inclination in two directions.

Lens holder 3 and relay member 6 that support objective lens 1
When the lens holder 3 is tilted in the X direction in FIG. 1 with the relay member 6 as a reference, the first parallel plate Two spring plates 4A parallel to each other forming a spring
, 4] and 3, the inclination can be corrected by loosening the machine screw 5A or 5B at the right end of one of the spring plates and relatively displacing the spring plates 4A and 4B in the left-right direction. Also,
Relay member 6 for the two spring plates 4A and 4B of the first parallel plate spring
If the right end portion connected to the first parallel plate spring 4A, 4Bi is attached with a relative shift vertically in FIG. 2;
Because of the i-twisting, the lens optical axis together with the lens holder 3 is tilted in the Y direction in FIG. In this assembly work, the inclination in the X direction is the two spring plates 4A of the first parallel plate spring.

:; It can be easily corrected by relatively shifting 4B in the left and right direction e. However, regarding the inclination in the Y direction, since the first parallel leaf springs 4A and 4B have a long length in the left and right direction, the relay member 6 should be installed at a different position, and the spring plates 4A and 4B
Even if one end of B is slightly shifted up or down in FIG. 2, the optical axis will not tilt slightly in the Y direction, so if the optical axis is tilted significantly in the Y direction, it is difficult to correct it.

On the other hand, when connecting the partially assembled relay member 6 to the rising portion 12A of the yoke 12 fixed to the plywood 10 via the second parallel leaf springs 14A and 14B, the relay member 6 shown in FIG. When the right side surface is tilted with respect to the top surface of the plywood 10, the lens optical axis along with the lens holder 3 is tilted in the X direction.

However, this inclination in the X direction can be easily corrected by reattaching the relay member 6 to the second parallel leaf springs 14A and 14B so that the right side surface of the relay member 6 is perpendicular to the top surface of the plywood 10. can.

In the assembled state where the first parallel leaf springs 4A, 413 and the second parallel leaf springs 14A, 14B are combined, experimental results show that the inclination in the X direction improves the machining accuracy (mainly squareness) of the parts to some extent. As a result, it became clear that assembly corrections were easy and assembly errors were less likely to occur. Therefore, it is only necessary to adjust the inclination in the Y direction.

Therefore, after confirming that the inclination in the X direction is within the allowable error range, the inclination in the Y direction is adjusted.

First, the two mutually parallel spring plates 14 of the second parallel plate spring
The other spring plate of A and 14B, for example 14B
Attach the rising portion 12A of the yoke 12 with the small screw 13A'.
Fix it on top. Next, the machine screw 13 of one spring plate 14A
Turn A' to raise the spring plate 14A and loosen the attachment of the ridge 12A to the extent that it can slide along the surface against the frictional force.

Furthermore, insert the tip of a rod-shaped tool such as a set screwdriver into the tool hole 15 of the loosened spring plate 14A, and then insert the tip of the tool into the V-shaped bottom of the tool groove 16 provided on the surface to attach the rising portion 12A. Let them come into contact with you. Therefore, the first parallel plate springs 4A, 4B can be attached by moving the handle of the rod-shaped tool in a direction perpendicular to the plane (flexible plane), that is, in the vertical direction in FIG. The left end can be moved slightly.

At this time, the left edge 14a (see FIG. 6) of the spring plate 14A moves vertically to the right side of the permanent magnet 9B in FIG. This means that there was a relative displacement of . Therefore, the relay member 6 is twisted in the Y direction, and together with the 1/lens holder 3, the optical axis Fi of the objective lens is
Only the tilt in the Y direction is corrected without tilting in the x direction.

After that, just tighten the machine screw 13'. With the above adjustment method, it is possible to easily correct a tilt of the optical axis of about 1 minute.

In addition, if it is necessary to adjust the height of the objective lens 1, the IC
First, the height of the objective lens 1 is adjusted by vertically moving one spring plate, for example 14B, of the second parallel plate springs 14A and 14B, and then slightly moving the other spring plate 14B vertically in the above-described manner. The tilt in the Y direction can be adjusted by Also, when it is desired to adjust the position by moving the lens optical axis of the objective lens 1 back and forth (direction perpendicular to the plane of the paper) and left and right in FIG. , drill hole 1'3 (fourth hole) provided on both sides of the rising portion 12A.
(see figure), the front, rear, left and right positions of the objective lens 10 can be adjusted.

Furthermore, if only tilt adjustment in the Y direction is required,
A tool hole 15 is provided only in one of the spring plates of the second parallel plate springs 14A, 14B, and a drill hole 16 is provided only in the surface for mounting the rising portion 12A. Y like this
In the case of only adjusting the inclination of the direction, a reference protrusion that determines the height standard is provided on the surface of the rising portion 12A for attaching the other spring plate, and the other spring plate is attached to this reference protrusion KG. This will make assembly easier.

〔Effect of the invention〕

As described above, according to the present invention, the lens that holds the objective lens is attached by relatively displacing one ends of two mutually parallel leaf springs constituting the second parallel leaf spring fixed to the fixed member. Since the holder is configured to be rotationally displaced in the direction of torsion of the second parallel plate spring, the inclination of the objective lens optical axis can be comprehensively corrected after the objective lens driving device is assembled. Since the optical axis tilt can be corrected within 1 minute at the mounting point, adjustment is easy and assembly work can be carried out efficiently.Moreover, no particularly expensive assembly jigs are required, resulting in extremely high performance. This has the advantage that an objective lens drive device with good performance can be provided at low cost.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a plan view of the embodiment of Fig. 1, Fig. 3 is a sectional view taken along line AA in Fig. Fig. 5 is a sectional view taken along line BB in Fig. 4, and Fig. 6 is a top view of Fig. 4 viewed from above. ] 1... Objective lens, 3... Lens holder, 4A,
4B...First parallel leaf spring, 7...Focusing coil, 8A, 8B...Tracking coil, 9A, 9B...
·permanent magnet,

Claims (2)

[Claims] (1) The first
In an objective lens driving device including a lens holder supported by a parallel leaf spring and a second parallel leaf spring so as to be movable in a focusing direction along the optical axis direction of the objective lens and a tracking direction perpendicular to this, one end is Of the two mutually parallel spring plates of the second parallel plate spring fixed to the fixing member, one end of one spring plate on the side fixed to the fixing member is connected to the other spring plate. A fine movement adjusting means is provided for relatively displacing the fixed member along the mounting surface in a direction perpendicular to the direction of deflection of the second parallel leaf spring, and when one end of the one spring plate is relatively displaced with respect to the other spring plate. The lens holder fixed to one end of the first parallel plate spring is rotationally displaced by the fine adjustment means in the direction of the twist of the second parallel plate spring that occurs in the optical system. Objective lens support device for optical recording and reproducing equipment. (2) The fine adjustment means includes the second parallel leaf spring (14
A, 14B)) A tool hole (15) provided at one end of at least one spring plate (14A) and into which a rod-shaped tool can be inserted.
and a tool groove (16) provided in the spring plate mounting surface of the fixing member (12).