JPH0676322A - Lens actuator - Google Patents

Abstract

PURPOSE:To make the required number of coils one-half of a conventional one and to provide a small sized and light weight lens actuator. CONSTITUTION:The right side part of a frame 11 having a throughhole 12 in the orthogonal direction to the wide surface of an actuator base 10 is fixed by means of a fixing pins 4 on the right side of the wide surface of the actuator base 10. The optical axis of an objective lens 2 is held in the orthogonal direction to the wide surface of the actuator base 10, a focusing coil 6 and tracking coils 7A-7B are held and a lens holder 3 connected to the frame 11 in the through-hole is provided by means of a double notched hinge part 53. Thin hinge parts 51A-51B, 52A-52B are provided in a through-hole 54 of the frame 11. A yoke 91 put through into the focusing coil 6 wound around the perpendicular axis to the wide surface of the actuator base 10 and being fixed on the actuator base at the lower end thereof, and a magnet 8 generating magnetic line of force run toward the yoke 91 are provided. The position of the objective lens 2 is mechanically modified by the current flowing through the coils.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens actuator, and more particularly, as a part of an optical head for irradiating a signal recording surface of an optical disk with light emitted from the outside and extracting reflected light from the recording surface. Lenses and actuators used

[0002]

2. Description of the Related Art A lens / actuator of the present invention records a signal on a disc surface by irradiating a signal recording surface on the disc surface of the optical disc with light output from an external light source perpendicularly to the disc surface of the optical disc by an objective lens. Used as part of an optical head that collects the light reflected from the surface by the objective lens described above and outputs it to the outside. When collecting the reflected light described above When the distance between the objective lens and the disc surface of the optical disk fluctuates , And when the signal recording portion of the target optical disc with respect to the objective lens is displaced in the radial direction of the optical disc, these are corrected.

FIG. 4 is a plan view showing an example of the structure of a conventional lens actuator of this type, and FIG. 5 (A) is a partial plan view of the frame 34 shown in FIG.
(B) is the front view.

As shown in FIG. 4, a conventional lens actuator of this type has a plate-shaped actuator base 31, and one end fixed to the actuator base 31 by a fixing pin 32 so that the wide surface is the aforementioned actuator base 31. The frame 34 that is parallel to the wide surface of 31 and the optical axis of the objective lens 2 are held while being held in a direction perpendicular to the wide surface of the actuator base 31, and the focus coil 3
8A to 38B and the lens holder 37 holding the track coils 41A to 41B and 42A to 42B, and one end of the lens holder 37 is fixed, and the other end is fixed to the upper surface which is the wide surface of the actuator base by the fixing pin 32. Is provided with a frame 34 that is parallel to the wide surface of the actuator base 31.

Further, this lens actuator is made of a magnetic material and has a rectangular parallelepiped outer shape. One end of the lens actuator is fixed to the upper wide surface of the actuator base 31, and the wide surface is kept in a direction perpendicular to the wide surface of the actuator base 31. Yokes 95A and 95B, and yokes 95A and 9
5B has magnets 39A and 39B each having an end face parallel to the wide face and having the bottom face fixed to the wide face of the actuator base 31 individually facing these yokes 95A and 95B. There is.

Further, in FIG. 4, a mirror (not shown) is fixed to the lower part of the actuator base 31 below the objective lens 2 (below the paper surface of FIG. 4), and the objective part within the actuator base 31 is fixed. A through hole is provided in a portion directly below the lens 2, and light incident from above the paper surface toward the objective lens 2 passes through the objective lens 2 and is reflected by the above-mentioned mirror to change its direction to the right parallel to the paper surface. It is designed to proceed. As shown in FIG. 5, the frame 34 has a substantially rectangular outer shape and has a through hole 63 that is parallel to the wide surface of the actuator base 31 and is orthogonal to the longitudinal direction of the frame 34. The vicinity is fixed to the actuator 31 with a fixing pin 32.

Notches having a V-shaped cross section are provided in the upper and lower inner sides of the through hole 63 of the frame 34, in the direction closer to the fixing pin, in a direction orthogonal to the longitudinal direction of the frame 34 and parallel to the upper surface of the frame 34. , And thin hinge portions 61A and 61B are formed, respectively. The tips of the cut portions of the thin hinge portions 61A and 61B are located in a plane that is orthogonal to the wide surface of the frame 34 and parallel to the side edges. Similarly, thin hinges 62A and 62B are also provided on the upper and lower inner sides of the through hole 63 farther from the fixing pin 32 in one plane orthogonal to the wide surface that is the upper surface of the frame 34 in the longitudinal direction. Has been.

Further, in the vicinity of an end portion on the left side in the longitudinal direction of the frame 34, a notched hinge portion provided with notches having a V-shaped cross section from both sides orthogonal to the longitudinal direction of the frame 34. 35 is composed. Therefore, the frame 34
When the left end portion of the shaft receives a rotational force in the clockwise or counterclockwise direction about the axis perpendicular to the paper surface in FIG. 5 (A) from the outside, it rotates around the rotation center 50 in accordance with the above-described rotational force.
It will rotate within a limited range.

Further, in FIG. 5A, the frame 34
When an external force is applied to the vicinity of the left end of the thin vertical hinges 61A to 61B and 62, the thin hinges 61A to 61B and 62
The portions A to 62B are deformed and the left end portion of the frame 34 is displaced above the plane of the drawing.

A part of the lens holder 37 is fixed to the upper part of the left end of the frame 34 with, for example, an adhesive.

The objective lens 2 is fixed to the lens holder 37 so as to be located on the side opposite to the rotation center 50 with respect to the frame 34. Also, focus coils 38A and 3
In FIG. 4, 8B is located above and below the center of rotation 50, and is fixed to the lens holder 37 with the yokes 95A and 95B inserted therein.
Each of the focus coils 38A and 38B has a winding axis that is a straight line in a direction perpendicular to the wide surface of the actuator base 31 and has windings wound around these winding axes, and yokes 95A and 95B are provided in these windings, respectively. It is fixed to the above-mentioned lens holder 37 with and inserted.

A yoke 95A is formed on the surface of the magnet 39A.
Lines of magnetic force are directed to the yoke 95A from the surface facing to. Lines of magnetic force are also perpendicular to the yoke 95B from the surface of the magnet 39B facing the yoke 95B.
Further, the directions of these magnetic lines of force are set so that the magnets 39A and 39B are oriented in a direction orthogonal to the longitudinal direction of the frame 34.
Is fixed to the upper surface of the actuator base 31.

When current is applied to these focus coils 38A and 38B in a fixed direction, the focus coils 38A and 38B exert a force perpendicular to the actuator base and upward in the plane of FIG. 2 from the yokes 95A and 95B, respectively. Will receive.

When a current in the opposite direction to that described above is applied to these focus coils, the focus coils 38A and 38B respectively apply forces in the opposite directions to those described above to the yoke 9.
You will receive from 5A and 95B. Therefore, the lens holder 37 fixing these focus coils 38A and 38B also receives the same force from the yokes 95A and 95B when the above focus coils receive it.
Thin hinge portions 61A-B and 62A- of the frame 34
B is deformed so that the left end portion of the lens holder 37 and the frame 34 fixed to the lens holder 37 is displaced in the direction perpendicular to the wide surface of the actuator 31, and the focus position of the objective lens 2 can be corrected.

The winding axes of the above-mentioned track coils 41A and 41B are parallel to the magnetic lines of force extending from the magnet 39A to the yoke 95A, and in FIG.
A track coil 41A is arranged and fixed to the lens holter 37 so that the magnetic force lines emitted from the magnet 39A penetrate the right half portion of the winding A.

Similarly, the magnetic field lines emitted from the magnet 39A are fixed to the lens holder 37 so as to pass through the inside of the left half of the track coil 42A.

A magnet 39B is provided on the right half of the winding portion of the track coil 41B and the left half of the track coil 42B.
The track coils 41B and 42B are positioned and fixed to the lens holder 37 in such a manner that the magnetic force lines toward the yoke 95B penetrate therethrough.

In this state, for example, when currents in opposite directions are respectively applied to the track coils 41A and 42A, the track coils 41A and 42A in FIG. 4 are formed between the magnet 39A and the magnetic force lines in the direction toward the yoke 95A. Means that the force toward the right or the left is received from the magnetic force lines formed by the magnet 39A. Here, it is assumed that the forces received by the track coils 41A and 42A are directed to the right in the figure. Such current is applied to the track coil 4
When the current is applied to 1A and 42A, a current is further applied to the track coils 41B and 42B to adjust the direction of the current, and the track coils 41B and 42B are moved from the magnet 39B to the yoke 95B by magnetic force lines in FIG. It is possible to receive a force to the left.
At this time, the lens holder 37 receives a torque directed counterclockwise as viewed from above the paper surface of FIG. 4 by the track coil described above, and the lens holder 3 rotates counterclockwise about the rotation center 50. Will move.

Therefore, the optical axis of the objective lens 2 is made orthogonal to the signal recording surface of the optical disc, the objective lens 2 is positioned on the signal recording surface side of the optical disc with respect to the actuator base 31, and the frame 34 If the longitudinal direction is arranged so as to be orthogonal to the radial direction of the optical disc, the objective lens 2 is moved by the above-mentioned actuators against the above-mentioned vertical movement of the optical disc surface relative to the objective lens 2 and radial movement of the optical disc. The position of can be modified.

[0020]

In the above-mentioned conventional lens actuator, the frame holding the lens holder on the actuator base has a rectangular shape, and the focus position of the objective lens is used as the displacement portion. During use, mechanical fluctuations are likely to occur due to rolling around a straight line in the longitudinal direction due to external force, which causes unnecessary fluctuations in the objective lens, thus degrading the output level and frequency characteristics of the signal focused by the objective lens. It has the drawback of

Further, since two focus coils and four track coils are used, it is difficult to make the outer shape small, and because the frame has the above-mentioned shape, it is not necessary to project the objective lens. Since it is difficult to install the mirror for changing the optical path of the incident light by 90 degrees to be parallel to the longitudinal direction of the frame on the wide surface side where the objective lens exists on the actuator base, It has to be installed on the side of the wide surface of the actuator base opposite to the objective lens, which has the drawback that the thickness of the lens actuator becomes large.

An object of the present invention is to reduce the number of focus coils and track coils described above to 1/2, to prevent the frame structure from being deformed by external force, and to use the mirror as a wide surface of the actuator base. It is to provide a lens actuator that can be provided on the same side as the objective lens, and can have a small outer shape and thickness.

[0023]

The lens actuator of the present invention is entirely displaced by an external force applied to a signal recording portion of a track portion spirally provided on the surface of an optical disc. The light emitted from an external light source for tracking is irradiated onto the signal recording unit through an objective lens at a right angle to the board surface, and the light reflected from the board surface is condensed again through the objective lens to the board surface. When the disc surface is converted into a parallel optical path and is sent out to the outside and a minute displacement occurs in the direction perpendicular to the disc surface during the tracking, an electric current applied to a focus coil from the outside causes the objective lens and the disc surface to be separated from each other. The light radiated from the objective lens to the target signal recording section of the track section during the tracking is adjusted in the radial direction of the optical disc during the tracking. In the lens actuator for correcting the position of the optical disk in the radial direction by applying an externally applied current for track adjustment to the track coil, the flat plate having a magnetic material portion made of a magnetic material at least near one end. -Shaped actuator base, and a first through hole that is orthogonal to the first and second wide surfaces and is provided inside the first and second wide surfaces facing each other in the rectangular parallelepiped outer shape. One outer side of the first wide surface is defined as a first side, and a protrusion is provided near the first side so as to project outward in a direction orthogonal to the first wide surface. The protruding portion is fixed to the wide surface of the actuator base at a position distant from the magnetic body portion in a state where the surface faces the wide surface of the actuator base in parallel to each other, and the first portion is formed by the rectangular parallelepiped. A side surface and an inner side that is orthogonal to the first wide surface and is orthogonal to the first and second side surfaces that face each other in parallel to each other and that is parallel to the outer sides of the first and second side surfaces are cross-sectioned. A frame having a rectangular second through hole formed therein, and the first wide width of two inner sides of the second through hole parallel to the first wide surface. A first thin-walled hinge portion near the first side edge and having a groove portion having a V-shaped cross section in parallel with the first wide surface and the first side edge on the inner side farther than the surface; First
And a second thin-walled hinge portion farther from the side edge of the second through-hole is provided, and the other inner edge of the two inner edges in the second through-hole is directly below the first thin-walled hinge portion. A third thin-walled hinge portion whose part has a V-shaped cross-section that faces downwards in parallel with the first thin-walled hinge portion and a second thin-walled hinge portion that is directly below the second thin-walled hinge portion. Located V
A fourth part having a shape in which the tip end of the V-shaped cross section faces the first wide surface.
And a thin rectangular hinge made of a magnetic material, one end of which is fixed to the frame side within the wide width surface of the magnetic material portion of the actuator base, and the wide surface direction is orthogonal to the wide surface of the actuator base. A first yoke having a wide surface parallel to the first side of the frame, and a wide width of the first yoke facing the wide surface of the first yoke parallel to the first side. A magnet for generating a magnetic field line in a direction substantially perpendicular to the plane; the focus coil wound around an axis perpendicular to the wide surface of the actuator base, and the yoke inserted in the center of the winding; The magnetic field lines of the focus coil and the magnet are generated by winding around a center line parallel to the generated magnetic force lines, and the winding portions are adjacent to the focus coil and contact each other at their outer circumferences. In a cross section parallel to the first wide surface, with two track coils partially inserted between the two, and the objective lens held at one end and the focus coil and the two track coils fixed at the other end. The projection is connected to the inner side of the inner side of the first through hole of the frame which is parallel to the first side and is distant by the protrusion, The lens is held in the first through hole in a state where the optical axis of the lens is orthogonal to the first wide surface, and is generated at a joint portion between the protrusion and the first side edge and a far inner edge. When a current is passed through the track coil around a rotation axis orthogonal to the wide surface of the first lens, the track coil is rotated to correct the track position of the objective lens, and when a current is passed through the focus coil, the lens holder is moved to the first position. Displace in the direction perpendicular to the wide surface of 1 It is constituted by a Nzuhoruda.

[0024]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1A is a plan view showing the construction of an embodiment of the lens actuator of the present invention, and FIG.
FIG. 2 is a vertical sectional view of the embodiment shown in FIG.

As shown in FIGS. 1 (A) and 1 (B), the lens actuator of this embodiment has a flat actuator base 10, a substantially rectangular outer shape, and a fixing pin near the right side edge. The frame 11 fixed to the wide upper surface on the right side of the actuator base 10 by means of 4 and the lower end fixed to the actuator base such that the wide surface is parallel to the right side of the frame, The yoke 91 having a rectangular parallelepiped outer shape made of a magnetic material provided on the left side, and a wide surface parallel to the wide surface of the yoke 91, which is located further to the left of the yoke 91, and the magnetic field lines H have A magnet 8 having a rectangular parallelepiped outer shape for generating a magnetic field directed in a direction perpendicular to the wide surface, and a yoke made of a magnetic material for fixing the magnet 8 and the actuator base 10. And a 2.

The region of the actuator base 10 connecting the fixed portions of the yokes 91 and 92 and the fixed portions of these yokes is made of a magnetic material.

The frame 11 is provided with a through hole 12 having a rectangular cross section which is orthogonal to the wide surface of the actuator base 10 (the surface parallel to the paper surface of FIG. 1A). Further, this lens actuator holds the objective lens 2 inside the through hole 12 provided in the frame 11 and is connected to the frame 11 inside the through hole 12 near the left side of the frame 11. It has a holder 3. The lens holder 3 has a focus coil 6 and a track coil 7A, which will be described later, on the left side outside the frame 11.
And holds 7B.

The focus coil 6 is wound around a winding axis perpendicular to the paper surface of FIG. 1 (A) and a yoke 91 is inserted therein. Also, the track coil 7A
7B and 7B have the same structure, and a straight line orthogonal to the left side of the frame 11 is used as the winding axis. These winding axes are defined by the objective lens 2 within a straight line in the lateral (left and right) direction of FIG.
Are equidistant above and below the straight line passing through the center of. The magnetic field lines H emitted from the magnet 8 are transmitted through the lower half of the track coil 7A and the upper half of the track coil 7B.

The lens actuator shown in FIGS. 1A and 1B is further provided with a mirror holder 13 fixed directly below the objective lens 2 on the wide surface above the actuator base 10. The back surface of the mirror 1 is fixed.

The mirror 1 converts the direction of the light Z incident on the upper wide surface of the actuator base 10 in parallel from the right direction to the left direction in the figure by 90 degrees and directs it toward the optical axis direction of the objective lens 2, and Light incident from the direction perpendicular to the actuator base 10 toward the objective lens 2 is converted into the direction of the light Z shown in the drawing. A through hole through which the light Z passes is provided in the lower part of the right side of the frame 11.

In the frame 11 described above, a through hole 5 having a substantially rectangular cross section that penetrates perpendicularly to the side surfaces 11A and 11B shown in FIG.
4 are provided. The thin-walled hinge portions 51A to 51B and the thin-walled hinge portion having a uniform V-shaped cross section in a plane parallel to the side surface 11A are provided on the two inner sides of the through hole 54 parallel to the wide surface of the actuator base 10. 52A-5
2B is provided. Thin hinge parts 51A and 51B
Means that the tip of the V-shaped cross section is located near the right side of the frame 11 and is located in a plane parallel to the side.

The thin-walled hinge portions 52A and 52B have a cross-sectional shape similar to the thin-walled hinge portions 51A and 51B near the left side of the frame 11 described above, and the V-shaped tip is parallel to the thin-walled hinge portion 51A. Is provided on the inner side of the through hole 54.

The lens holder 3 and the frame 11 have a cross section parallel to the wide surface of the actuator base 10 in the inner side portion on the left side of the through hole 12 of the frame 11, and the cross section from both the upper and lower sides in FIG. They are connected by both notched hinge portions 53 having a V-shaped notch.

Therefore, as shown in FIG.
When an external force parallel to the paper surface of (A) is applied, it is rotated about a rotation center 9 that passes through the centers of the notch hinge portions 53 and is orthogonal to the wide surface of the actuator base 10.

FIG. 2 shows that an external force is applied to the lens holder 3 of the lens actuator of the embodiment of the present invention shown in FIGS. 1A and 1B in a direction perpendicular to the wide surface of the actuator base 10. It is a side view which shows the state when it is twisted.

The lens holder 3 is the actuator base 1.
When receiving an external force in a direction perpendicular to the wide surface of 0 and away from the actuator base 10, the thin hinge portions 51A to 51B and the thin hinge portions 52A to 52B provided on the frame 11 are parallel to the paper surface of FIG. It is deformed inside and the lens holder 3 is displaced in a direction away from the actuator base 10. In such cases,
The direction of the optical axis of the objective lens 2 held by the lens holder 3 is kept substantially perpendicular to the wide surface of the actuator base 10.

When a current in a fixed direction is passed through the focus coil 6 of the lens actuator shown in FIGS. 1A and 1B, the magnetic field lines H and the current flowing through the focus coil 6 are The focus coil 6 and the lens holder 3 fixing this coil are fixed to the actuator base 10 by the interaction between the current flowing in the focus coil 6 between the yoke 91 and the magnet 8.
Receives a force in a direction perpendicular to the wide surface of the actuator, and this force displaces the frame 11 in a direction perpendicular to the wide surface of the actuator base 10. That is, the focus of the objective lens 2 can be corrected by appropriately adjusting the direction and magnitude of the current flowing through the focus coil 6.

When currents in opposite directions are applied to the track coils 7A and 7B, a current component parallel to the plane of the paper of FIG. The forces are opposite to each other and cancel each other out, and a current component flowing in a direction perpendicular to the paper surface causes a force in a direction orthogonal to the magnetic field lines H and parallel to the paper surface to act in the same direction on the track coils 7A and 7B. When working
The lens holder 3 will rotate around the rotation center 9.

If the longitudinal direction (light Z) of the actuator base 10 is made to coincide with the direction orthogonal to the radial direction of the target optical disk, the track coils 7A and 7B will have a proper size and orientation. By passing a current having the above value, it is possible to correct this deviation when the irradiation position of the light output from the objective lens 2 on the optical disk deviates from the radial direction of the optical disk.

FIG. 3A is a plan view showing the structure of another embodiment of the present invention, and FIG. 3B is a vertical sectional view thereof.

In the embodiment of the present invention shown in FIG. 3A, the point that the lens holder 3A is attached to the frame 11C by this part where both the notch hinge portions 53 are provided on the left outer side of the frame 11C is shown. 1A has the same configuration as that of the embodiment shown in FIG. 1A except that the embodiment shown in FIG.

Therefore, even with the lens actuator having the structure shown in FIGS.
Obviously, the same operation as the lens actuator shown in FIGS. 1A and 1B can be performed.

[0044]

As described above, the lens of the present invention
The actuator can perform the same operation as a conventional lens actuator of this type even if the required amount of the focus coil and the track coil is halved compared with the conventional one, so that the overall size and weight can be reduced. Since the frame has a structure in which the distance between the outer surfaces parallel to the optical path Z is large, it is possible to reduce the rolling of the frame due to an external force, and the mirror is on the same wide side of the actuator base as the objective lens. By arranging the lens actuator in the above-mentioned manner, it is possible to realize a lens actuator in which the thickness of the actuator base in the direction perpendicular to the wide surface can be reduced.

[Brief description of drawings]

FIG. 1A is a block diagram showing the configuration of an embodiment of a lens actuator of the present invention. Figure 1 (B)
FIG. 2 is a vertical sectional view of FIG.

FIG. 2 is a side view showing a deformed state of the lens holder and the frame shown in FIGS. 1 (A) and 1 (B).

FIG. 3 (A) is a plan view showing a configuration of an embodiment of the present invention different from that of FIG. FIG. 3B is a vertical sectional view of FIG.

FIG. 4 is a plan view showing an example of a conventional lens actuator of this type.

5 (A) is a plan view of the frame in FIG. 4. FIG. FIG. 5 (B) is a side view of FIG. 5 (A).

[Explanation of symbols]

 1 Mirror 2 Objective Lens 3 Lens Holder 4 Fixing Pin 6 Focus Coil 7A-7B Track Coil 8 Magnet 10 Actuator Base 11 Frame 11C Frame 91 Yoke 92 Yoke

Claims (2)

[Claims] 1. A light emitted from an external light source is tracked by displacing the whole of a signal recording portion of a track portion spirally provided on the surface of an optical disc by an external force. The signal recording unit is irradiated through the objective lens orthogonally to the board surface, and the light reflected from the board surface is condensed again through the objective lens, converted into an optical path parallel to the board surface, and sent to the outside. When the disc surface undergoes a minute displacement in a direction perpendicular to the disc surface during the tracking, the distance between the objective lens and the disc surface is adjusted by an electric current applied to a focus coil from the outside, and the track portion is adjusted during the tracking. When the light radiated from the objective lens to the target signal recording portion of (1) is displaced in the radial direction of the optical disc, track adjustment applied from the outside is performed. In a lens actuator for applying a current for use in a track coil to correct the position of the optical disc in the radial direction, a flat plate-shaped actuator base having a magnetic material portion made of a magnetic material at least near one end and a rectangular parallelepiped outer shape. A first through hole orthogonal to the first and second wide surfaces is provided inside the first and second wide surfaces facing each other, and one outer side of the first wide surface is defined as a first through hole. The first wide side is parallel to the wide side of the actuator base, and the first side is parallel to the first wide side. Fixed to a position farther from the magnetic body portion with the wide surface of the actuator base, the rectangular parallelepiped is orthogonal to each of the first side and the first wide surface. In addition, a rectangular second through hole is provided which is orthogonal to the first and second side surfaces facing each other in parallel and has an inner side in cross section which is parallel to the outer sides of the first and second side surfaces. Of the two inner sides of the frame and the inner side of the second through hole which are parallel to the first wide surface, the inner side of the inner side farther than the first wide surface has the first wide width. A first thin-walled hinge portion that is parallel to the surface and the first side edge and has a V-shaped groove in cross section, and is close to the first lateral edge; and a second thin-walled hinge portion that is farther from the first lateral edge. Is provided, and the other inner side of the two inner sides in the second through hole is parallel to the first thin-walled hinge portion at a portion directly below the first thin-walled hinge portion, respectively. The tip of the V-shaped cross section is parallel to the third thin-walled hinge portion facing downward and the second thin-walled hinge portion, and is located immediately below the second thin-walled hinge portion. And a fourth thin-walled hinge portion having a shape of a letter-shaped cross-section facing the first wide surface, the rectangular parallelepiped shape made of a magnetic material, and one end of the wide surface of the magnetic material portion of the actuator base. A first yoke fixed to the frame side and having a wide surface whose direction of the wide surface is orthogonal to the wide surface of the actuator base and parallel to the first side of the frame; and parallel to the first side. A magnet that faces the wide surface of the first yoke and generates magnetic lines of force in a direction substantially perpendicular to the wide surface of the first yoke; and the winding wound around an axis perpendicular to the wide surface of the actuator base. The focus coil, in which the yoke is inserted in the center of the line, and the winding part wound around the center parallel to the magnetic force line generated by the magnet, are adjacent to the focus coil and contact each other with their outer circumferences. The two track coils partially inserted between the focus coil and the surface of the magnet that generates the magnetic force lines, and the objective lens held at one end and the focus coil and the two track coils fixed at the other end Within the inner side of the first through hole of the frame, which is parallel to the first side and is far from the inner side of the first through hole, which protrudes in a direction orthogonal to the first side in a cross section parallel to the first wide surface. The projection is connected to the inner side and is held in the first through hole in a state where the optical axis of the objective lens is orthogonal to the first wide surface, and the inner side is far from the protrusion and the first side. When a current is passed through the track coil around a rotation axis orthogonal to the first wide surface generated at the junction with the side, the track coil is rotated to correct the track position of the objective lens, and the focus coil is moved to the focus coil. The lens when the current is applied Lens actuator, comprising a lens holder for displacing in a direction perpendicular to the first wide plane holder. 2. The lens actuator according to claim 2, wherein the protrusion of the lens holder is connected to a second side of the outer peripheral portion of the frame parallel to the first side outside the frame. The optical axis of the objective lens is orthogonal to the first wide surface by the lens holder and is held in the first through hole, and the focus coil and the two track coils are provided outside the frame. And a state in which the yoke is inserted inside the focus coil.