JPS60136041A - Pickup for reproducing optical information - Google Patents

Abstract

PURPOSE:To improve productivity by uniting parts of the objective lens holder Assy of an actuator and reducing adhesive parts. CONSTITUTION:Yoke insertion parts 7-70 and 7-71 in a recessed groove shape are formed in flanks of an objective lens holder 7-26 in a quadrangular prism shape in parallel to an optical axis m-m. Focusing coil winding parts 7-27 and 7-35 are formed in a bobbin shape by forming a recessed groove with depth DELTA corresponding to the number of turns of focusing coil in four surfaces of the quadrangular prism. A suspension leaf spring fixing part 7-51 is formed in a flank difference from the flanks of said yoke insertion parts in level with upper and lower surfaces 7-31 and 7-32 of said recessed grooves. Then, 7-60 is the insertion part for an objective lens 7-1. Therefore, there are only three parts, i.e. the objective lens 7-1, the lens holder 7-26, and a balance weight 7-14 and only the balance weight 7-14 is adhered.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an optical information reproducing pickup that improves productivity and magnetic efficiency.

[Background of the invention]

For products that are mass-produced, such as home appliances, in order to reduce production costs, make them cheaper, and increase product value,
Improving productivity is important.

Particularly for products that are completed by combining many parts, it is necessary to average productivity for each part. For example, if the productivity of one part is low, the overall productivity will decrease. I will do it.

Optical information reproducing pickups are also composed of many optical components.

That is, a plurality of optical axes are set in a pickup case of an optical information reproducing pickup, and a plurality of optical components and actuators are mounted on each optical axis.

Since this pickup is mainly intended for home appliances that apply optics, such as CDs (compact disc players) and optical VDPs, it is necessary to have a highly productive structure suitable for mass production.

However, this pickup requires highly accurate alignment of the optical axes of the optical components, and the mass production and assembly of the actuator is extremely time-consuming.
This has become a major technical barrier to achieving high productivity, and has become a technical issue that must be resolved as soon as possible.

Among these, the present invention is aimed at high productivity of the actuator section.

A representative example is shown in FIG. 1 below, and an overview of the optical information reproducing pickup will be explained.

This optical information reproducing pickup has three optical axes l-1, m-m, and nn set in a pickup case 1.

On each optical axis, there is a light emitting source (laser diode) 2. Coupling lens 39 Diffraction grating 4. ...-7
Prism 5. A total reflection prism 6, an actuator 7, a cylinder lens 8, and a light receiving section 9 are provided. Further, the optical axes of these optical components are adjusted within a predetermined precision and assembled. Its outline is shown in Figure 2.

The actuator 7 has the following functions. That is, the actuator 7 is equipped with an objective lens 7-1, and the laser light emitted from the laser diode 2 is
Light enters the objective lens 7-1 through the plurality of optical systems described above, and is applied to the recording surface 12 of the disk 12 by the actuator 7.
The light is always focused on a spot of about 1 on the recording surface 12-1, and by tracing the pitches 12-2 on the track formed at a pitch of about 1.6 μm on the recording surface 12-1, Read out multiple signals from the signal plane.

The depth of focus of the objective lens 7-1 is set to several micrometers due to constraints such as the focal spot diameter and the weight of the lens, but on the other hand, the disk experiences a maximum surface deflection of about 0.5 m when the disk is rotating. .

Therefore, it is necessary to drive the objective lens 7-1 in the direction of the optical axis m-m in order to always focus the laser beam onto a spot of a predetermined diameter on the disk recording surface depending on the surface runout state of the disk. be.

In addition, the tracking accuracy of the laser beam is set to 0.1 μm for the tracks formed on the recording surface of the disk 12, and the tracking accuracy of the laser beam is set to 0.1 μm. The track experiences fluctuations of up to 0.3 degrees in the tracking direction.

Therefore, it is necessary to make the light spot follow this track variation.

In this way, the actuator 7 can displace the objective lens 7-1 in two directions: the optical axis m-m direction (focusing direction) in response to disk surface runout, and the direction perpendicular to the optical axis mm (tracking direction) in response to track fluctuations. , has a two-dimensional actuator structure.

The return light reflected from the disk 12 passes through the actuator 7 and reaches the light receiving section 9 via a plurality of optical components.

Pit information, focus deviation information, and tracking deviation information on the disk surface are obtained by the laser beam incident on the light receiving section 9, and the information is tracked while correcting deviations in the focus direction and tracking direction through the light receiving section (not shown).

In this way, the actuator 7 has a two-direction drive mechanism in the focusing and tracking directions to always focus the laser beam onto a predetermined spot diameter on the disk recording surface while the disk 12 rotates, and to prevent it from deviating from the track. have

A conventional actuator will be described next.

In FIG. 3, actuator 7 includes actuator pace 7-2. Magnetic circuit component consisting of magnet and yoke 7-3. The objective lens holder As5y75+ is equipped with the objective lens 7-1, focus coil 7-6, racking coil 7-7, etc., and is composed of two types of parallel springs so that it can be displaced in two directions. The suspension consists of Aasy7-4.

In this actuator 7, the conventional objective lens holder As5y75 was configured as follows.

In FIG. 4, objective lens holder 7-5 is connected to objective lens holder 7-10. Pre-formed focus coil 7
-6, focus coil press plate 7-15, objective lens 7
-1. It was composed of seven parts: a suspension fixing plate 7-11, 7-12 and a balance weight 7-14.

The seven parts mentioned above were assembled as follows.

First, the focus coil 7 is attached to the objective lens holder 7-10.
-6 is fitted into the flange 7-10-1, and the lower end of the focus coil 7-6-1 is provided on the objective lens holder 7-10.
, 7-10-2 for positioning and adhesive fixation.

Next, the focus coil holding plate 7-16 is placed on top, and the claw 7-13-1 provided on the focusing coil holding plate 7-15 is
~7-13-4, position the focus coil by pressing the upper end 7-6-2. Next, after fitting and positioning the objective lens 7-1 t'' into the hole 7-13-5.7-10-3,
The claws 7-13-1 to 7-13-4, the objective lens holder 7-10°, and the objective lens 7-1. Objective lens holder 7
-10° hole 7-15-5 is fixed with adhesive.

Next, the legs 7-11-1, 7-11-2 and 7-12-1.7 provided on the suspension fixing plates 7-11 and 7-12
-12-2 is fitted into the recess provided in the focus coil holding plate 7-13 and the recess provided in the objective lens holder 7-10, and the focus coil Jt4F is inserted between the plate 7-13 and the objective lens holder. Assemble and adhesively fix 7-10, then balance weight 7-1
4. Glue and fix.

Objective lens holder As5y assembled in this way
The parallel spring 7-15 installed so as to be displaceable in the tracking direction is connected to the suspension fixing plate 7-11.7-12.
Position it and fix it with adhesive.

Finally, as shown in FIG. 5, the terminal wires 7-6-3 and 7-6-4 of the focus coil are attached to the suspension plate spring parts 7-15-1' and 7-15-2'. The assembly is then completed in the form shown in FIG.

As described above, the conventional objective once halter A11Iy has a large number of parts, and since the parts are positioned and fixed by adhesive, it takes a long time for the adhesive to harden.

In addition, variations in the adhesive layer and adhesive distortion may occur, making it impossible to perform stable and high-precision assembly, resulting in a significant decrease in yield. was a major hindrance, and the overall productivity was extremely poor.

[Purpose of the invention]

The present invention aims to provide an optical information reproducing actuator that solves the above-mentioned conventional drawbacks.

[Summary of the invention]

That is, the present invention provides an objective lens holder Aa of an actuator.
By integrating the parts that make up the SY, the number of parts can be reduced.
In addition, the assembly time is greatly reduced by reducing the number of adhesive parts, and the objective lens holder is formed into a rectangular prism. A yoke insertion part in the shape of a groove is provided perpendicular to the plane, and grooves with a depth corresponding to the number of turns of the focus coil are provided on the four sides of the objective lens holder formed into the square prism, thereby forming a bobbin-shaped focus coil winding part. A suspension leaf spring fixing part is provided so as to protrude from the opposite side surface, which is different from the side surface on which the yoke insertion part is provided, so as to be flush with the upper and lower side walls of the concave groove of this focus coil winding part. A feature of the lens holder is that an objective lens insertion hole is provided in the center of the lens holder.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below. First, the outline of this embodiment will be explained using FIG. 6.

In the figure, 7-26 is a square prism-shaped objective lens holder. Reference numerals 7-70 and 7-71 denote yoke insertion portions that are vertically provided in the form of grooves on opposing side surfaces of a square prism so as to be parallel to the optical axis m-m.

Reference numerals 7-27 and 7-55 denote focus coil winding parts, which are formed into a bobbin shape by horizontally providing grooves with a depth Δ corresponding to the number of turns of the focus coil on four sides of a square prism. 7-51 is a suspension plate spring fixing part, and the upper and lower side surfaces 7-31, 7 of the concave groove of the focus coil winding part
-32 so that the yoke insertion part 7-70 is flush with the
．． 7-71 is provided so as to protrude from the opposite side surface. 7-60 is a hole into which the objective lens 7-1 is inserted.

Therefore, the number of parts in this embodiment is as follows: objective lens 7-1, objective lens holder 7-26, and balance weight 7-14.
Of these, only the balance weight 7-14 is bonded.

The details of this embodiment will be explained in more detail below. In FIG. 6, the objective lens holder 7-26 includes the yoke insertion portion 7-70, 7-71, as explained in the above-mentioned overview.
A focus coil winding portion 7-27° 7-35, a suspension plate spring fixing portion 7-50° 7-51, and a hole portion 7-60 into which the objective lens 7-1 are inserted are provided.

The suspension plate spring fixing parts 7-50 to 7-53 (
Similarly, attach the suspension plate spring fixing part 7 to the target surface.
-52 and 7-53 are formed), narrow grooves 7-50-1 and 7-51-1 with a width δ are cut. Of course, narrow grooves 7-52-1 and 7-53-1 are also cut in the suspension leaf spring fixing parts 7-52 and 7-56, respectively. Further, the suspension plate spring identification portions 7-50 to 7-53 are formed with protruding portions in the shape of a wide dance.

7-15-1 to 7-15-4 are suspension plate springs, and the suspension plate spring fixing parts 7-50 to 7
-53 pores 7-50-1, 7-51-1,
A recessed portion having a thickness δ81 and a width W8 is formed so as to be fitted into and fixed to 7-52-1 and 7-53-1.

If the wire diameter of the coil winding is N, and the above-mentioned dimensional relationship is expressed by the following formula, the following formula is obtained.

We = WB + ΔS, δ = δs + Dw + Δ1゜ (
Δ'I +Δafi > 0, Δ88. Δ112 =
0) The corners of the upper and lower side walls 7-31 and 7-32 are chamfered 7-69 to facilitate winding of the focus coil.

7-60 is a hole for inserting an objective lens, and this hole 7-60 is a hole for inserting an objective lens.
A stepped portion 7-61 is provided so as to protrude from the inner periphery of 60,
Insert the objective lens 7-1 into the hole 7-60 and
By bringing the lower end surface 7-1-1 of the lens barrel of the objective lens 7-1 into surface contact with -61, the objective lens holder 7-26 and the objective lens 7-1 are positioned in the optical axis m-m direction. It has become so. Reference numeral 7-14 is a balance weight, which is press-fitted and fixed to the lower part of the objective lens holder 7-26. This balance weight 7-14 is omitted if the weight of the objective lens holder Assy can be balanced by itself.

The operation of this embodiment configured as above will be explained next. First, the focus coil is directly wound around the focus coil winding portions 7-27 and 7-35 provided on the objective lens holder 7-26.

At this time, the end treatment of the focus coil wire at the beginning and end of winding is performed as shown in FIG.

Immediately, suspension/john plate spring fixing part 7-50 to 7-56
Narrow grooves 7-50-1, 7-51-1, 7-5 provided in
2-1.7-53-1, focus coil wire 7-90
Insert the suspension plate spring 7-15-1~
7-15-4 is fitted from above to establish electrical continuity between the two. In this case, electrical continuity between the suspension plate spring and the coil end may be established within the narrow groove using a conductive adhesive or laser welding.

The focusing coil can be wound by rotating the objective lens holder 7-26 around the optical axis mm, or by fixing the objective lens holder 7-26 and rotating a wire around it. It may be wound around 1.

FIG. 7 shows a state in which the focus coil is wound in this manner. In the figure, 7-80 is a wound focus coil. Also, suspension board No. 17-15-1 to 7-15
-4 is in electrical continuity with the focus coil 7-80, and the suspension plate screw fixing portions 7-50 to 7-
It is fixed at 56. Further, the objective lens 7-1 has a hole 7
-60, it is held in alignment with the optical axis of the objective lens holder 7-26.

”T-spension board bar $7-15-1 to 7-15-
4 is assembled as follows. First, install the lower suspension leaf springs 7-15-1 and 7-15-4,
Place the objective lens holder Aasy on top of it, and
50-1, and 7-53-1.

Next, move the upper suspension plate bar * 7-15-2 upwards to the door 15-3, and similarly move the narrow grooves 7-51-1 and 7-5.
Insert into 2-1.

In this way, the suspension plate springs are assembled by mounting them in order from top to bottom.

Next, as shown in FIG. 8, the yoke insertion part 7-70°7-
The yoke 7-7, 7-8 is inserted into the yoke 71, and the assembly of the actuator 7 is completed.

Further, in FIG. 8, the gap Gm where the magnetic field is formed between the yoke 7-8 and the magnet 7-6 degrees and between the yoke 7-7 and the magnet 7-5 can be made sufficiently narrow. In other words, the magnetic efficiency is considered to be inversely proportional to the distance between the magnet 7-6.7-5 and the yoke 7-7.7-8, so by making this gap as narrow as possible, the magnetic efficiency can be increased. improves.

Although the tracking coil was not specifically explained, it may be wound on the focus coil 7-80.
Even in this case, the distance between the axes can be made sufficiently narrow.

〔Effect of the invention〕

According to the actuator of the present invention as described in detail above, the number of parts and the number of bonding steps are reduced, so that assembly accuracy and productivity can be greatly improved.

Furthermore, since the distance between the yoke and the magnet could be narrowed, a direct winding structure of the focus coil with high magnetic efficiency could be achieved.

Improving the assembly accuracy, productivity, and magnetic efficiency of the actuator in this way will improve the productivity and reliability of the optical information reproducing big Arab, and will have a great industrial effect.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing a typical example of an optical information reproducing pickup for explaining its outline. FIG. 2 is a perspective view of the assembled optical information reproducing pickup. FIG. 6 is a perspective view of the actuator section. FIG. 4 is an exploded perspective view of a conventional actuator. FIG. 5 is a perspective view showing the appearance when the device shown in FIG. 4 is assembled. 6 to 9 show one embodiment of the present invention, FIG. 6 is an exploded perspective view of the objective lens holder As@y, and FIG.
The figure is a perspective view showing the assembled appearance, FIG. 8 is a perspective view showing the magnetic circuit section installed in the objective lens holder Asay, and FIG. 9 is a partially enlarged view of the suspension plate screw fixing section. FIG. 7-1... Objective lens, 7-26... Objective lens holter, 7-27, 7-35... Focus coil winding part, 7-70, 7-71... Yoke insertion part, 7
-50 to 7-56... Suspension plate nook fixing part, 7-60... Hole part. Agent Patent Attorney Tadashi Akimoto Figure 1 19-I Figure 2 14-1 Figure 4 715 1 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. A groove-shaped yoke insertion portion provided perpendicularly to a plane perpendicular to the optical axis so as to be parallel to the optical axis on opposing sides of an objective lens holder formed in a square prism; , a bobbin-shaped focus coil winding portion with grooves having a depth corresponding to the number of turns of the focus coil on four sides of the objective lens holder formed in the shape of a rectangular prism; A suspension plate spring fixing part and an objective lens holter are provided so as to protrude from a side face different from the side face on which the yoke insertion part is provided so as to be flush with the side wall. An optical information reproducing pickup consisting of an objective lens insertion hole provided in the center of the i=. 2. The suspension plate spring fixing part according to claim 1, wherein the suspension plate spring fixing part is provided with a thin groove into which the suspension plate spring is inserted together with the end of the coil wire. Pickup for information reproduction.