JPS6199594A - Cutting method of plate spring for holding objective lens for optical pickup - Google Patents

Abstract

PURPOSE:To perform a cutting work with high yield of the titled plate spring having no deflection, burr, deformation, etc. by cutting via the laser beam of YAG laser, etc. the plate spring base metal consisting of with inserting a rubber layer between copper alloy spring plates. CONSTITUTION:The blank 23 of a plate spring for holding the objective lens of an optical pickup, the upper and lower faces of which are composed of copper spring plates and which is made with inserting a rubber layer therein, is placed on a work platform 22. Said work platform 22 is made to be of the structure that a recessed groove is cut on the part to be cut of the base metal in advance and yet composed of the materials of metal, ceramics, etc. Said blank 23 is then subjected to a cutting work by irradiating with reducing the laser beam 21 of YAG laser, Co2 laser, ruby laser, etc. to the fine diameter of about 10mum. The spring 24 for holding the objective lens for optical pickup having good dimensional accuracy is thus obtd. With more than about 90% yield of said blank 23 without causing a deflection, burr, the swelling of rubber layer, deformation, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a method for cutting a leaf spring for holding an objective lens of an optical pickup.

The pickup of a conventional optical information reading device generally includes a laser diode 1. as shown in FIG. Collimator lens 2
．． Polarizing plate 3. First prism 4°V4 wave plate5. Objective lens 6, actuator T.

Second prism8. It is composed of a critical angle prism 9, a photodiode 10, etc., and a laser diode 1
The laser beam emitted from the 3. First prism4. V4 wave plate 5. The light is incident on the disk 11 through the objective lens 6, and the reflected light from the disk 11 is reflected through the objective lens 6.
74 wavelength plate 5° first prism 4. Polarizing film 3. The information recorded on the disc 11 is configured to be detected by the photodiode 10 via the second prism 8 and the critical angle prism 9 (using the two-person rule).

The actuator 7 is used to perform focusing and tracking control by moving the objective lens 6 in the optical axis direction and radial direction, and is usually constructed as shown in FIG. 4. That is, reference numeral 12 denotes a pair of leaf springs that support the objective lens 6, and are configured to be elastically deformable so as to move the objective lens 6 in a direction perpendicular to its optical axis. The leaf spring 12 has its lower end fixed to a spacer 14 provided on the inner peripheral surface of the bobbin 13.
The pobbin 13 is connected to the objective lens 6 via a second leaf spring 15.
It is movable in the optical axis direction and supported by the main body part 16.
has been done.

As shown in FIG. 5, the teaching springs 12 and 15 are composed of copper alloy spring plate parts 17 and 17 and a rubber layer 18.
It is composed of a sandwich structure sandwiched between. The purpose of this configuration is to prevent vibration damping of the leaf springs 12 and 15 due to displacement of the objective lens 6 and resonance at the natural frequency of the copper alloy spring plate portion 17.

the above! ! Conventionally, the leaf springs 12 and 15 made of ItI5112 are cut into a predetermined shape by punching and cutting using a male punch 19 and a female punch 20, as shown in FIG. Was.

However, the above conventional cutting method has the following problems.

(1) As shown in ￥J7ヅfat, leaf spring 12,
12a, 15a around 30μ nail sag around 15
This sag 12a, 15a (greatly affects the controllability of the two objective lenses 6, and sag 12a, 15a)
If 15a is large, it may become impossible to control the objective lens 6. In addition, the ease of assembling the leaf springs 12 and 15 to the actuator 7 is poor, and the misalignment between the objective lens 6 and the fixed part 14 is less than 0.1 fl (the two-pronged distance is 9), but this precision is not enough. was also having a negative impact.

(2) As shown in Fig. 7 fbl, the cutting part (Nipari 1
2b, +5b occurs, and this Paris 12b, 15b
Therefore, the same as the above-mentioned sagging 12a and 15a (2. The curvature control property of the objective lens 6, the ease of assembly when assembling the leaf springs 12 and 15 to the actuator 7, and the dimensional accuracy of the product after assembly are extremely poor. It became.

(3) As shown in Fig. 7 fc), the rubber layer 18 at the center of C2 protruded by 50 μmit during cutting, and the same opening and closing as in (2) above occurred due to the protruding portion of the rubber layer 18. .

(4) As shown in FIG. 5(d), since the leaf springs 12 and 15 were stretched during punching, deformation as shown in the figure occurred after cutting, and dimensional accuracy could not be controlled.

(5) For punching, the leaf springs 12 are effectively formed from the leaf spring materials 12c and 15c as shown in FIG. 7(e).
It was not possible to punch out 15°, and the yield was low at about 50°, making it uneconomical.

OBJECTS OF THE INVENTION The present invention has been made in view of the problems of the prior art described above, and provides a leaf spring for holding an objective lens of an optical pickup, which allows the leaf spring to be cut without causing sagging, cracking, or deformation. The purpose is to provide a cutting method.

Summary of the invention The present invention is a YAG laser and a carbon dioxide laser.

The above object of the present invention is achieved by cutting a leaf spring from a temporary spring material using a laser beam such as a ruby laser.

Embodiments Hereinafter, embodiments of the present invention will be described in detail using the drawings from Figure S1 onwards.

FIG. 1 is a perspective explanatory view showing a method of cutting a plate spring for holding an objective lens of an optical pickup according to the present invention C1.

As shown in the figure, the present invention cuts a leaf spring material (leaf spring base material) 23 on a processing table 22 vertically and horizontally using a laser beam (laser beam) 21 to obtain a leaf spring 24 of predetermined dimensions. It is something.

As the laser beam 21, a YAG laser, a carbon dioxide laser, a ruby laser, etc. are used, and the laser beam 21 is narrowed down to a minute diameter of 10 μm 8f to cut the plate spring material 22, which is the workpiece. .

The plate spring material 23, which is the workpiece, is placed on a processing table 22 that has a groove cut in the part of the base material to be cut in advance, and is shaped like a C2 so as to be cut. The structure is designed to avoid the effects of turbulence and fusion of the base material to the processing table 22, and to improve the escape of spatter.

And, uh, ka. Engineering, □2. ) Oh'l'f,! :L
-Yo, □, Yau.

However, when using a laser whose wavelength is outside the absorption band of glass, such as a YAG laser or a ruby laser, the material of the processing table can be glass, and in this case, the laser beam 21 The influence of the base material on the processing table and the influence of the base material on the processing table are eliminated.

The cut peripheral part of the leaf spring 24 cut by the above method is shown in FIG. 2. As shown in the figure, according to this method, the rubber Wj2
The upper and lower copper alloy spring plate parts 26, 26 sandwiching the rubber layer 25 are melted by the laser beam 21C, and the cut surface of the rubber layer 25 can be covered with the melted copper alloy spring plate parts 28, 26. be. Therefore, according to the one method, FIG.
The protrusion of the rubber layer as shown in Fig. 2 is completely eliminated, and the problem of poor control of the objective lens caused by such protrusion of the rubber layer is solved, and the controllability of the objective lens and leaf spring 2 are improved.
4. Assembling property to the actuator 2. The dimensional accuracy of the product after assembly can be improved.

In addition, since the melting and scattering process is performed by heating via the laser beam 21, there is no occurrence of cracks as shown in FIG. Since such external forces are not applied, sag as shown in FIG. 7 (at) does not occur.

Therefore, it is possible to prevent processing distortion from occurring.

Further, deformation as shown in FIG. 7(d) does not occur, and the dimensional accuracy is 0.01 wm 8g, which is significantly improved compared to conventional press cutting. As a result, Paris
It is possible to prevent poor control of the objective lens due to sag or deformation due to dimensional defects, improving the controllability of the objective lens.

It is possible to improve the ease of assembly, improve the misalignment accuracy between the objective lens and the leaf spring fixing part, and improve the dimensional accuracy of the product after assembly. Furthermore, since the leaf spring material 23 is cut simply by being placed on the processing table 22, the entire leaf spring material 23 can be effectively manufactured into a product, and all parts other than the parts melted and scattered due to heating can be manufactured into products. It can be used as As a result, the yield of the leaf spring material 23 can be significantly improved to 90% or more.

Effects of the Invention As described above, according to the present invention, the following effects can be achieved.

m There is no cracking, sag, deformation, or protrusion of the rubber layer during cutting, and the dimensional accuracy of the leaf spring can be kept within 0.01 steel.

(2) As a result, it is possible to improve the controllability of the objective lens, the ease of assembling the leaf spring to the actuator, the assembling strength, and the dimension of the assembled product by 17 degrees.

(3) Significant improvement in yield of leaf spring materials can be seen.

[Brief explanation of drawings]

° Figure 1 is a perspective view showing an embodiment of the method according to the present invention, Figure 2 is a sectional view of the method according to the present invention (2) is a cross-sectional view of the cut section, and Figure 3 is a schematic diagram of a general optical pickup. 532 and 4 are cross-sectional views of the actuator gun, FIG. 5 is a structural view of the plate spring for holding the objective lens of the optical pickup, FIG. 6 is a cross-sectional explanatory view showing the conventional cutting method, and FIG. 7 (a) ),
(b), (cl, (d), (el is an explanatory diagram showing the problems of the conventional technology. 21...Laser beam 22...Processing table (F&I table) 23. ...Plate spring material 24...Plate spring (after cutting) Fig. 8 1, 1 Fig. 4 Fig. 5 Fig. 6 q 1 tl'l) + 20 7th (a ) (d' (b) (e)

Claims (3)

[Claims] (1) In a method for cutting a leaf spring for holding an objective lens of an optical pickup, the leaf spring for holding an objective lens of an optical pickup is constructed by having the upper and lower surfaces made of copper alloy spring plates and interposing a rubber layer between the copper alloy spring plates. A method for cutting a leaf spring for holding an objective lens of an optical pickup, characterized in that a base material of the leaf spring is cut using a laser beam such as a YAG laser, a carbon dioxide laser, or a ruby laser. (2) Cutting a leaf spring for holding an objective lens of an optical pickup according to claim 1, wherein the laser beam is narrowed down to a minute diameter of about 10 μm and irradiated onto the leaf spring base material. Method. (3) The objective of the optical pickup according to claim 1, wherein the plate spring base material is cut while the plate spring base material is simply placed on a mounting table. How to cut a leaf spring for holding a lens.