JPH02189730A - Lens actuator for optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To constitute a moving part with simple structure and light weight and to reduce the split vibration by selecting an outer diameter of a cylindrical main body to be small and arranging a ring part provided to both sides of the cylindrical main body within one plane including the center axis of the cylindrical main body. CONSTITUTION:A moving part of a lens actuator 3 is made up of only a cylindrical main body 30 whose diameter is substantially far smaller and two blades 32, 32 projected to both sides of the cylindrical main body 30, then the entire weight is made light. Moreover, the cylinder with a smaller diameter in this way is a shape withstanding much any deformation and since the two blades 32, 32 are in existence within a plane determined by a focusing direction (a) and a tracking direction (b), a planer vibration hardly takes place. Thus, the moving part is formed with simple structure and light weight, and there is almost no factor of split vibration and uniform vibration characteristic up to a high frequency region is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lens actuator for a recording/reproducing device for recording or reproducing optical information.

[Conventional technology]

In recent years, optical recording and reproducing devices such as compact discs (CDs) have been rapidly becoming popular, and external memories for computers, cash cards, and the like are becoming optical. In such an optical recording/reproducing device,
Optical heads are required to record information on and read information from record carriers such as disks and cards.

Conventional examples of such optical heads are shown in FIGS. 3 and 4, respectively.

FIG. 3(A) shows the structure of an actuator for an optical pickup as an optical head. In this lens actuator 1, a lens supporter 11 is attached to the upper end of a cylindrical base 10. The objective lens 12 is mounted on the lens support section ll. A focus adjustment coil 13 is wound around the outer peripheral surface of the cylindrical base IO of the lens actuator 1, and further,
A tracking adjustment coil 14.14 consisting of a plurality of flat coils is disposed on the outer peripheral surface of this focus adjustment coil 13.
is fixed.

In the figure, 15 is a shaft that movably supports the lens actuator l with a spring or the like, and 16 is a balancer.

This lens actuator 1 is shown in FIGS.
) is arranged in the magnetic circuit shown in This magnetic circuit includes a cylindrical yoke 17a provided in the center, an arcuate yoke 17b arranged around the outer periphery of this cylindrical yoke 17a,
17b, and a magnet 18 fixed to the inner peripheral surface of the arcuate yoke 17b. And the third
The lens actuator 1 shown in FIG. 1A is arranged such that its cylindrical base 10 is inserted from above into the gap between the cylindrical yoke 17a and the magnets 18, 18 of the magnetic circuit.

Then, by passing current through the focus adjustment coil 13 and the tracking adjustment coil 14, which are attached to the outer peripheral surface of the cylindrical base lO of the lens actuator 1, the lens actuator 1 adjusts between the focusing direction a and the tracking direction. , and make each adjustment.

FIG. 4A shows another example of optical pickup, and the lens actuator 2 in this example is equipped with a cylindrical lens support 20 having a large diameter. And this lens support 2
An objective lens 21 is attached to the upper end surface of the lens support 20, and a focus adjustment coil 22 is wound and attached to the outer circumferential surface of the lens support 20. A tracking adjustment coil 23 is fixedly attached.

As shown in FIG. 4(B), CD), the magnetic circuit for this lens actuator 2 consists of a pair of yokes 24, 24 each having a rectangular cross section, and a flat plate-shaped portion at the rear end of this yoke 24. The magnet 25 is fixed to the inner surface of the portion 24a. The front end side of the yoke 24 is formed into an arcuate portion 24b, and the lens support 20 of the lens actuator 2 is disposed between the outer peripheral surface of the arcuate portions 24b, 24b and the magnet 25.

[Problem to be solved by the invention]

The two types of lens actuators 1.2 described above both have complicated structures, making it difficult to reduce their overall dimensions. Furthermore, the weight of the movable part of the lens actuator inevitably increases, resulting in poor vibration characteristics and a problem in that undesirable split resonance occurs frequently. FIG. 3(C) and FIG. 4(C) show the most basic resonance mode of each lens actuator.

Further, in these lens actuators 1.2, for example, the focus adjustment coil 13.23 is wound around the outer peripheral surface of the cylindrical body, so the winding work is complicated, and it is particularly difficult to automate the work. It was difficult. Also, gluing another coil (for example tracking adjustment coil 14, 23) onto this winding was also relatively cumbersome because the surface of the winding was not flat.

Even in the relatively small optical pickups used in CD players and LD (optical video disc) players, which have recently become popular, the focus adjustment coil is wound around the outer circumferential surface of a cylindrical body. Therefore, its manufacture was relatively complicated.

[Means to solve the problem]

The present invention is intended to solve the above problems, and has the following features:
As shown in the figure, a lens support 30 has a cylindrical main body 30a to which a lens 31 is attached to one end, a pair of wing-shaped parts 32 and 32 provided on the side surfaces of this cylindrical main body 30a, and each of the wing-shaped A focus adjustment coil 33 and a tracking adjustment coil 34 are fixed to the part 32, and a magnetic flux generating means 36 is arranged to face each wing part 32. The focus adjustment coil 33 and the tracking adjustment coil 34 are arranged in one plane along the axial direction of the cylindrical main body portion 30, and each of the focus adjustment coil 33 and the tracking adjustment coil 34 is configured in a flat plate shape.
The magnetic flux generating means 36 is connected to the focus adjustment coil 3.
The present invention relates to a lens actuator for an optical recording/reproducing device, characterized in that the magnetic flux is provided so that the magnetic flux passes through a part or all of each of the tracking adjustment coil 34 and the tracking adjustment coil 34.

[Effect]

The lens actuator 3 configured as described above is, for example,
The cylindrical main body 30a is supported by a casing (not shown) with a spring or the like, and a focus adjustment coil 33
By supplying control currents to the tracking adjusting coil 34 and the tracking adjustment coil 34, the focusing direction A and the tracking direction A are moved.

〔Example〕

Hereinafter, an embodiment will be described in which the lens actuator for an optical recording/reproducing device according to the present invention is applied to a lens actuator for an optical pickup.

As shown in FIG. 1, the lens support 30 of the lens actuator 3 of the present invention has a cylindrical main body 30a, and an objective lens 31 is attached to the upper end surface of the cylindrical main body 30a. There is.

As shown in the figure, in the lens support 30 of this embodiment,
The cylindrical main body 30a has an outer diameter considerably smaller than that of the conventional one shown in FIGS. 3 and 4, and is close to the outer diameter of the objective lens 31. The objective lens 31 is attached to the upper end surface of the cylindrical main body 30 so as to be concentric with the cylindrical main body 30 . An optical path of an objective lens 31 is formed inside this cylindrical main body part 30.

As shown in the figure, a pair of wings 32, 32 are provided on the side surface of the cylindrical main body 30 on both sides of the cylindrical main body 30. Each wing-shaped portion 32 is formed into a rectangular flat plate shape, and these wing-shaped portions 32 are arranged so as to exist within one plane containing the central axis of the cylindrical main body portion 30.

A focus adjustment coil 33 and a tracking adjustment coil 34 are fixed to one surface of each wing-shaped portion 32, respectively. These coils 33 and 34 are so-called flat coils in which coated conductive wires are wound in advance into a rectangular parallelepiped flat plate and solidified with an adhesive or the like.
3.34 are fixed to each wing-shaped portion 32 with adhesive in a predetermined direction.

The magnetic circuit that drives the lens support 30 of the lens actuator 3 includes a pair of yokes 35 and 35 having a rectangular cross section, and magnets 3G and 36 fixed to the inner surface of the vertical wall of the yoke 35. It is composed of.

FIGS. 2(A) and 2(B) show the positional relationship between the lens support 30 and this magnetic circuit.
is arranged so that each of its wing-like parts 32 is located within the gap of each yoke 35, and the magnet 36 attached to these yokes 35 is arranged so that the coil attachment of each wing-like part 32 partially faces the surface. being done.

In a normal state, the coils of each wing-shaped portion 32 are attached so that about half of each of the focus adjustment coil 33 and the tracking adjustment coil 34, which are fixed to the surface, are inside this magnetic circuit.

By supplying control currents to these coils 33 and 34, the lens support 30 of the lens actuator 3 is driven in the focusing direction a and the tracking direction, respectively, and adjustments are made.

At this time, in the configuration of this embodiment, the movable part of the lens actuator 3 is substantially composed of a cylindrical main body 30 having a considerably small diameter and two pieces protruding from both sides of the cylindrical main body 30. Due to only the wing sections 32, 32, its overall weight can be made very light. Further, such a small diameter cylinder has a shape that is extremely resistant to deformation, and the two wing-shaped portions 32, 32 are aligned in the focusing direction a.
Since the lens actuator 3 of this embodiment is configured to exist within a plane determined by the tracking direction and the tracking direction, the plane vibration is least likely to occur.Therefore, in the lens actuator 3 of this embodiment,
There are almost no split vibration elements, and uniform vibration characteristics can be obtained up to the high frequency range.

In addition, in this embodiment, the focus adjustment coil 3
3 and the tracking adjustment coil 34, and since these coils are fixed to a flat surface by adhesive, manufacturing thereof is very easy. In other words, it is difficult to automate the conventional method of winding a cylindrical body, but a flat coil like the one in this example can be mass-produced, and it can be attached by bonding it to a flat surface. Automation is possible because all you have to do is Therefore, the lens actuator 3 of this embodiment has good productivity and can be manufactured at low cost.

Although not shown in the drawings, the lens support body 30 of the lens actuator 3 is coupled and held by a spring to a casing surrounding the lens actuator 3.

Above, an embodiment in which the lens actuator for an optical recording/reproducing device according to the present invention is applied to a lens actuator for an optical pickup has been described, but the present invention can also be applied to a lens actuator for an optical head for writing optical information. It is possible.

〔Effect of the invention〕

According to the present invention, the movable part of the lens actuator can be constructed with a simple structure and lightweight, and its divided vibration can be significantly reduced, so the lens actuator has uniform vibration characteristics up to a high frequency range. can be provided.

Furthermore, since the focus adjustment coil and the tracking adjustment coil can be manufactured and attached very easily, automation thereof becomes possible, and lens actuators can be manufactured in large quantities at low cost.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing the configuration of a lens actuator of an optical pickup according to an embodiment of the present invention, and FIG.
A) is a side view showing the positional relationship between the lens support body and the magnetic circuit, and FIG. 2(B) is a top view of the same. Figure 3 (A) is a side view showing the configuration of a conventional lens actuator, Figure 3 (B) is a top view showing the configuration of the same magnetic circuit as above, and Figure 3 (C) is the fundamental resonance mode of this lens actuator. 3(D) is a side view of FIG. 3(B). FIG. 4(A) is a side view showing the configuration of another conventional lens actuator, FIG. 4(B) is a top view showing the configuration of the same magnetic circuit, and FIG. 4(C) is the basics of this lens actuator. A conceptual diagram showing the resonance mode, FIG. 4(D) is a side view of FIG. 4(B). DESCRIPTION OF SYMBOLS 3... Lens actuator, 30... Lens support body, 30a... Cylindrical main body part, 31... Objective lens, 32... Wing-shaped part, 33... Focus adjustment coil, 34...・Tracking adjustment coil, 36...
・Magnet. Patent Applicant: Japan Victor Co., Ltd. Representative Kakiki Japanese Diagram (8) Diagram (D) (v no (v) 1) λ Day 2, Name of the Invention: Lens Actuator for Optical Recording and Reproduction Design 3° Correction Person Case and Relationship

Claims (1)

[Claims] A lens support body having a cylindrical main body to which a lens is attached at one end, a pair of wing-shaped parts provided on the side surface of the cylindrical main body, and a focus adjustment coil and a tracking adjustment coil fixed to each of the wing-shaped parts. Each of the wing-shaped parts includes a coil and a magnetic flux generating means arranged opposite to each wing-shaped part, and the pair of wing-shaped parts are arranged in one plane along the axial direction of the cylindrical main body part, The focus adjustment coil and the tracking adjustment coil are each formed into a flat plate shape, and the magnetic flux generating means is provided so that the magnetic flux passes through a part or all of each of the focus adjustment coil and the tracking adjustment coil. A lens actuator for an optical recording/reproducing device, which is characterized by: