JPH0973642A - Optical pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a movable body supporting means without being affected by friction and resistant to disturbance and the optical pickup device high in sensitivity. SOLUTION: The supporting means is composed of leaf springs 1a and 1b, bearings 2a and 2b and axes 3a and 3b, and is formed by integrating the leaf springs 1a and 1b in an approximately X-shape and the bearings 2a and 2b into one body, inserting the axes 3a and 3b into the bearings 2a and 2b respectively and then press-fitting the axes 3a and 3b into a holder 11 with a slight gap between the bearings 2a and 2b and the holder 11 respectively. Then, a movable body is turned and is driven in the direction of F by electromagnetic interaction between double-pole magnetized magnets 43a, 43b, 47a and 47b and air-core elliptical coils 41a, 41b, 45a and 45b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device in an optical recording / reproducing device.

[0002]

2. Description of the Related Art Various optical pickup devices are used in an optical recording / reproducing device, and these optical pickup devices are disclosed in, for example, Japanese Patent Publication No. 60-30017 and Japanese Patent Publication No.
Many were shown in -39743.

In the former known technology, the rotating body is supported so as to be rotatable around a certain axis and slidable along the axis.

In the latter known technique, the holder is supported by the two leaf spring portions having flexibility in the optical axis direction and the direction orthogonal to the optical axis, and the magnet magnetized in the thickness direction as the driving means. A part of the coil is arranged in the magnetic air gap of the magnetic circuit consisting of the yoke and the U-shaped yoke.

[0005]

However, in the above-mentioned supporting method of the prior art, the effect of friction load between the shaft and the bearing can be ignored when rotating with respect to the shaft, but the effect of friction load can be ignored. When it slides, it hinders the movement of the holder, which may cause a problem in controlling the drive of the holder. As a countermeasure against this, there is a method of reducing the friction coefficient of the sliding surface. However, not only the methods are insufficient, but the cost of parts is increased.

Further, there is a problem in that there is no means for determining the neutral position of the holder in the rotating direction.

Since the latter known technique is supported only by the spring, it is easily affected by external vibration or force. For example, when the optical pickup device is moved to a desired position on the recording medium, The holder may vibrate due to inertial force, and the next operation may not be possible until the vibration is stopped.

Further, since the magnetic pole is a single pole on one surface of the magnet facing the coil as the driving means, the ratio of the portion effective for generating the driving force of the coil is small and a large driving force can be generated. Since it is difficult, it is difficult to realize the optical pickup device in which the optical components such as the light emitting means, the light collecting means and the light receiving means of the present invention are mounted in the holder, and further, the optical pickup device in which only the light collecting means is mounted in the holder. However, there is a problem that it is difficult to realize a highly sensitive device.

In view of the above-mentioned prior art, the present invention (1) eliminates the adverse effect of friction, (2) maintains the neutral direction of the holder rotation direction, (3) is resistant to external vibration and external force, and (4) is a large drive. An object of the present invention is to provide an optical pickup device with high sensitivity by force.

[0010]

An optical pickup device according to the present invention comprises: (1) An axis center perpendicular to the plane of the recording medium, which has a holder holding a light-collecting element for irradiating a recording surface of the recording medium with a light spot. Has a first supporting means for rotatably supporting the holder and a second supporting means for movably supporting the holder in a direction orthogonal to the recording medium plane, and the second supporting means has the shaft. It is held by a fixing member arranged substantially radially from the center and symmetrically with respect to the recording medium tangent line and the radial direction,
Further, it is characterized in that it is composed of an elastic body carrying the first supporting means, and the first and second supporting means are respectively arranged above and below the holder.

(2) A holder holding at least optical components such as a light emitting element, a light converging element and a light receiving element for irradiating a light spot on the recording surface of the recording medium is centered on an axis perpendicular to the plane of the recording medium. It has first supporting means for rotatably supporting it and second supporting means for movably supporting the holder in a direction perpendicular to the plane of the recording medium, the second supporting means being substantially from the axis. The holder is composed of an elastic body that is held by fixing members that are radially and symmetrically arranged in the recording medium tangential line and in the radial direction, and that carries the first supporting means, and the first and second supporting means are each the holder. It is characterized by being placed above and below.

(3) The fixing member is arranged in four directions from the axis.

(4) It is characterized in that it has connection means for electrically connecting to the optical component, and the connection means is fixed at a plurality of locations near the fixing portion.

(5) First driving means for rotatably driving a holder, which holds a condenser for irradiating a light spot on the recording surface of the recording medium, about an axis perpendicular to the plane of the recording medium. A second drive means for driving the holder in a direction orthogonal to the recording medium plane, and one first drive means each in a direction orthogonal to the axis and parallel to a tangential direction of the recording medium. The magnetic poles of the magnets constituting the first driving means are substantially equally divided in a plane including the shaft center and parallel to the tangential direction.

(6) A holder, which holds at least optical components such as a light emitting element, a condensing element, and a light receiving element for irradiating a light spot on the recording surface of the recording medium, is centered on an axis perpendicular to the plane of the recording medium. A direction that is perpendicular to the axis and parallel to the tangential direction of the recording medium, which has a first driving unit that rotationally drives and a second driving unit that drives the holder in a direction orthogonal to the recording medium plane. One of the first driving means is arranged in each of the first and second driving means, and the magnetic poles of the magnets forming the first driving means are substantially equally divided in a plane including the shaft center and parallel to the tangential direction. And

(7) The invention is characterized in that the two second driving devices are respectively arranged in the radial direction of the recording medium.

(8) All or part of the holder is made of a metal containing magnesium as a main component.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an exploded perspective view of a main part of the present invention, and FIG. 2 shows a perspective view of the present invention. The holder 11 is made of a metal containing magnesium as a main component, and has an optical unit 21, which integrally includes a light emitting element, a light receiving element, a light diffraction element, and the like.
An optical component such as an objective lens 22 forming a light-collecting element is mounted to form a movable body.

Magnesium is lighter in weight than other light metal materials such as aluminum alloys and has high rigidity and high thermal conductivity as compared with resin materials such as PPS, so that high sensitivity and prevention of unnecessary resonance are achieved. Also, it is optimal for the requirements required of the optical pickup device such as high heat dissipation.

Light emitted from the optical unit 21 is emitted in the tangential direction of the recording medium 1 (X direction in the drawing, hereinafter X direction) and recorded by a mirror (not shown) arranged below the objective lens 22 of the holder 11. The optical path is changed in a direction orthogonal to the plane of the medium 51 (F direction in the figure, hereinafter F direction), and spot light is formed on the recording medium 1 via the objective lens 22. The reflected light from the recording medium 1 reaches the optical unit 21 through a path opposite to the above, is converted into an electric signal, and is transmitted as various electric signals to a circuit board (not shown) arranged in the fixed portion. In this embodiment, all electric signals are generated by the reflected light received by the optical unit 21, but a part of the reflected light may be received by the light receiving means provided in the fixed portion.

Next, the supporting means will be described.

Reference numeral 1a is a leaf spring, which is made of a copper spring material or a stainless steel spring material having a thickness of 10 to 50 μm and is formed into a substantially X shape. This makes it easy to bend in the F direction but hard to bend in the X and Y directions. That is, even if an external force is applied to the device, the movable body is less likely to be affected. A hole 101a is provided near the center of the substantially X shape,
The four spring ends are also provided with holes 102a to 105a, respectively.

Reference numeral 2a is a bearing made of a resin having excellent slidability, and has a hole 201a having a diameter smaller than that of the hole 101a in the center portion.
Is provided. In this embodiment, the bearing 2a is made of resin, but may be made of metal such as copper alloy.

The bearing 2a is integrated with the leaf spring 1a by adhesion or outsert molding.

Reference numeral 3a denotes a bearing 2 which is an axis and is integrated with the leaf spring 1a.
Although it is inserted into the hole 201a of a and further press-fitted into the hole provided in the holder 11, at this time, a slight gap between the upper surface of the holder 11 and the lower surface of the bearing 2a is sufficient to allow the holder to smoothly rotate. Press in.

In the present embodiment, the shaft 3a is directly press-fitted into the holder 11, but the shaft 3a may be press-fitted into another member and then that member may be fixed to the holder. Alternatively, the holder may be provided with a columnar protrusion serving as a shaft, and after the bearing is fitted to the protrusion, a retaining process (for example, E-ring) may be performed.

The supporting means described above is similarly constructed on the lower surface of the holder 11 by the leaf springs 1b, the bearings 2b and the shafts 3b, and four leaf springs 1a and 1b are provided near the ends of the fixing portions. Holes 102a-105a, 102b
.About.105b and the pins 31a to 31d, which form a fixed portion and are arranged at positions substantially equal in distance from the rotation axis, serve as positioning means for the movable body, and each of the four spring ends is fixed to the fixed portion.

As a result, the movable body is supported by the shaft and the bearing so as to be rotatable in the R direction in the drawing and to be movable in the F direction by the leaf spring. In the present embodiment, the above-mentioned positioning means for the movable body is performed by means of holes and pins, but positioning by means of contact or the like may also be used.

Further, the plane shape of the leaf spring may be a shape which is line-symmetric with respect to the X- and Y-direction axes and has the same spring constant in each flexible portion, and as shown in FIG. 3, the flexible portion 106a.
The same effect can be obtained by bending ~ d.

Reference numeral 4 denotes a flexible printed circuit (connecting means) which electrically connects the optical unit 21 and a coil (which will be described later in detail) which constitutes the driving means, and an electric circuit board (not shown) arranged in the fixed portion. Hereinafter FPC).

The FPC 4 is fixed at four points on the side surface in the Y direction of the movable body constituted by the holder 11 and the like, and is then fixed to the fixed portions near the pins 31a to 31d while being bent in a U shape. As a result, the moments about the X, Y, and F axes applied to the movable body by the reaction force of the FPC 4 cancel each other out, so that the movable body is stabilized and further, the movable body can be always held at a constant position. .

In this embodiment, the FPC 4 is connected to the movable body Y.
Although it is drawn from four points on the side surface in the direction, the same effect can be obtained by drawing it from the side surface in the X direction.

Next, the driving means will be described.

41a and 41b are rotary coils which are wound into an air-core oval or rectangular shape, and are then bent to form a cylindrical surface having a radius substantially equal to the distance from the rotary shaft as a radius. . The rotating coils a and b are fixed to the bobbins 42a and 42b, respectively, with the major axis direction being the F direction, and then the X of the holder 11 is moved.
Mount on each side. At this time, the rotating coil 41
Although a and b may be directly mounted on the holder 11, in order to prevent the temperature rise of the movable body due to heat generation of the coil, bobbins 42a and 42b are used in this embodiment.

Numerals 43a and 43b are rotating magnets, and a cylindrical surface having a radius of a length substantially equal to the distance from the rotating shaft is a surface facing the coil, and an XF plane including the rotating shaft in the cylindrical surface. Since the rotating coils 41a and 41b are magnetized in two poles with respect to the boundary, the rotating coils 41a and 41b receive a magnetic flux effective for generating a rotating driving force by an electromagnetic action and generate a large driving force.

The rotating magnets 43a and 43b are respectively provided with a yoke 44.
It is fixed to a and b by adhesion or the like, and further fixed to a fixing plate 32 that constitutes a fixing portion.

Focusing coils 45a and b, 47
Reference numerals a and b are focusing magnets and reference numerals 48a and 48 are focusing yokes, which constitute a driving means for driving the movable body in the F direction. The focusing coils 45a and 45b and the focusing magnets 47a and 47b have cylindrical surfaces similar to those of the rotating coil and the rotating magnet, respectively, and face each other with the cylindrical surfaces facing each other. The focusing coils 45a and 45b are mounted on the side surfaces of the holder 11 in the Y direction with the major axis in the X direction via bobbins 46a and 46b, respectively. Further, since the focusing magnets 47a and 47b are substantially equally divided by the XY plane on the cylindrical surface and are each magnetized to have two poles,
A large driving force can be obtained similarly to the above-mentioned rotation driving means.

The focusing magnets 47a, 47b are fixed to the fixed portion via focusing yokes 48a, 48b, respectively.

As described above, the movable body is rotated in the R direction and driven in the F direction.

In this embodiment, the coil is mounted on the movable body and the magnet is arranged on the fixed portion side. However, the same effect can be obtained by fixing the coil on the fixed portion and mounting the magnet on the movable body. .

Further, in this embodiment, the holder is provided with the optical components such as the light emitting element, the light collecting element and the light receiving element,
For example, the same effect can be obtained when only the objective lens forming the light-collecting element is mounted on the holder.

Further, although the disk-shaped recording medium is shown in the present embodiment, the optical pickup device of the present invention can obtain the same effect even in a non-disk-shaped recording medium such as an optical card. . In the case of a non-disc-shaped recording medium, the T direction in the drawing is the data array direction.

[0044]

As described above, according to the present invention, the following effects can be obtained. (1) Since the leaf spring, the bearing and the shaft are used as the supporting means, the influence of friction can be eliminated and the movable body can be moved or rotated smoothly.

(2) The substantially X-shaped leaf spring enables a device resistant to lateral vibration and external force.

(3) The movable body can be held at a fixed position by the FPC.

(4) A magnet with two poles and an air-core elliptical coil generate a large driving force, and a lightweight movable body realizes a highly sensitive device.

(5) A movable body having a high heat dissipation property can be realized by a holder containing magnesium as a main component.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of essential parts of an optical pickup device of the present invention.

FIG. 2 is a perspective view of an essential part of the optical pickup device of the present invention.

FIG. 3 is a plan view showing another embodiment of the leaf spring of the present invention.

[Explanation of symbols]

 1a, b Leaf spring 2a, b Bearing 3a, b Axis 4 Flexible printed circuit (FPC) 11 Holder 21 Optical unit 22 Objective lens 31a-d pin 32 Fixing plate 41a, b Rotating coil 42a, b Rotating bobbin 43a, b Rotating magnet 44a, b Rotating yoke 45a, b Focusing coil 46a, b Focusing bobbin 47a, b Focusing magnet 48a, b Focusing yoke 51 Optical recording medium

Claims (8)

[Claims] 1. A first supporting means for supporting a holder, which holds a light collecting element for irradiating a light spot on a recording surface of a recording medium, so as to be rotatable about an axis perpendicular to the plane of the recording medium. An optical pickup device having second supporting means for movably supporting the holder in a direction orthogonal to the recording medium plane, the second supporting means being substantially radial from the axis and tangential to the recording medium. And an elastic body which is held by fixing members symmetrically arranged in the radial direction and which carries the first supporting means, and the first and second supporting means are respectively arranged above and below the holder. An optical pickup device characterized by: 2. A holder, which holds at least optical components such as a light emitting element, a light converging element, and a light receiving element for irradiating a light spot on a recording surface of a recording medium, is rotated about an axis perpendicular to the plane of the recording medium. An optical pickup device having a first supporting means for movably supporting the holder and a second supporting means for movably supporting the holder in a direction orthogonal to the plane of the recording medium, wherein the second supporting means is The first and second supports are formed of an elastic body that is held by fixing members that are substantially radial from the axis and symmetrical about the recording medium tangent line and the radial direction and that carries the first supporting means. An optical pickup device characterized in that means are respectively arranged above and below the holder. 3. The optical pickup device according to claim 1, wherein the fixing member is arranged in four directions from the axis. 4. The optical pickup device according to claim 2, further comprising connecting means for electrically connecting to the optical component, wherein the connecting means is fixed at a plurality of locations near the fixing portion. 5. A first driving means for rotatably driving a holder, which holds a light collecting element for irradiating a light spot on a recording surface of a recording medium, around an axis perpendicular to the plane of the recording medium. An optical pickup device having a second drive means for driving a holder in a direction orthogonal to the recording medium plane, wherein the first drive is orthogonal to the axis and parallel to a tangential direction of the recording medium. Place one means each,
An optical pickup device characterized in that the magnetic poles of a magnet constituting the first driving means are divided substantially equally in a plane including the shaft center and parallel to the tangential direction. 6. A holder, which holds at least optical components such as a light emitting element, a condensing element, and a light receiving element for irradiating a light spot on a recording surface of a recording medium, is rotated about an axis perpendicular to the plane of the recording medium. An optical pickup device having a first driving means for driving dynamically and a second driving means for driving the holder in a direction orthogonal to the plane of the recording medium, the optical pickup device being orthogonal to the axis and tangential to the recording medium. One each of the first driving means is arranged in a direction parallel to the direction,
An optical pickup device characterized in that the magnetic poles of a magnet constituting the first driving means are divided substantially equally in a plane including the shaft center and parallel to the tangential direction. 7. The optical pickup device according to claim 5, wherein the two second driving devices are respectively arranged in the radial direction of the recording medium. 8. The optical pickup device according to claim 2, wherein all or part of the holder is made of a metal containing magnesium as a main component.