JPH07254159A - Objective lens drive - Google Patents

Abstract

(57) [Abstract] [Purpose] Achieves accurate focus control and tracking control without causing resonance during driving, with good response even at high frequency servo currents, and with durability against temperature changes. . A bobbin 36 having an objective lens 33 attached thereto is moved in the optical axis direction of the objective lens 36 by first and second displacement members 41a and 41b arranged in parallel to a direction orthogonal to the optical axis direction of the objective lens 36. A supporting member 4 which is displaceably supported, is located between the first and second displacement members 41a and 41b, and supports the first and second displacement members 41a and 41b.
The third elastic member 43 having the hinge portion 46 integrally provided on the one side surface of 0 is rotatably supported in the direction orthogonal to the optical axis direction of the objective lens 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates an optical recording medium such as an optical disc for recording information signals such as audio signals and video signals with a light beam to reproduce the information signals recorded on the optical recording medium. Alternatively, the present invention relates to an objective lens driving device used for an optical pickup device of a recording and / or reproducing device for recording an information signal on the optical recording medium.

[0002]

2. Description of the Related Art Conventionally, in a recording and / or reproducing apparatus such as an optical disc player for recording and / or reproducing an information signal on an optical recording medium by using a light beam such as a laser beam, the light beam is optically recorded. An optical pickup device is used which irradiates a medium and detects a return light beam from the optical recording medium.

In this optical pickup device, a light beam emitted from a light source such as a semiconductor laser is accurately focused on a signal recording surface of an optical disc rotated at a high speed, and a recording track of the optical disc is accurately tracked. For,
Objective lens driving device for performing tracking control and focusing control for driving and displacing the objective lens for focusing the light beam on the signal recording surface of the optical disc in the focusing direction parallel to the optical axis and in the tracking direction orthogonal to the optical axis. Is provided.

In the optical pickup device used in the recording and / or reproducing device, an objective lens is orthogonal to each other in a direction parallel to the optical axis and a direction orthogonal to the optical axis on an optical system block containing a semiconductor laser. An objective lens driving device for driving and displacing in two axial directions to control tracking and focusing is attached.

As this objective lens driving device, a device configured as shown in FIGS. 11 and 12 is used. The objective lens driving device shown in FIGS. 11 and 12 is curved in an arc shape on a mounting substrate 1 made of a high magnetic permeability material such as soft iron that is a mounting portion to an optical system block and constitutes a yoke of a magnetic circuit portion. The pair of formed fan-shaped first outer peripheral side yokes 2, 2 and the pair of inner peripheral side yokes 3, 3 are arranged at a predetermined interval so as to face each other and form a magnetic gap, and Focusing magnets 4 and 4 are arranged below the first outer yokes 2 and 2. Then, the tracking magnets 6 are bonded and compounded to the opposing surfaces of the pair of second outer peripheral yokes 5 and 5 which are erected so as to be located between the first outer peripheral yokes 2 and 2, and the magnetic circuit portion is formed. Make up 7.

A spindle 8 is planted on the mounting substrate 1 having the magnetic circuit portion 7 as described above so as to be located at the center of the magnetic circuit portion 7. A cylindrical bobbin 1 in which an objective lens 10 held by a lens barrel 9 is attached to the support shaft 8 at a position separated from the axial center, that is, at a decentered position.
1 is rotatable and displaceable via a cylindrical boss portion provided at the axis,
Further, it is inserted and supported so as to be slidable in the axial direction of the support shaft 8. The bobbin 11 thus supported by the support shaft 8 is a rubber that is elastically displaceable so that the optical axis of the objective lens 10 and the optical axis of the optical system block coincide with the tracking direction at the neutral point, which is the inoperative state position. It is held by an elastic holding member 12 made of a material or the like. This elastic holding member 12 is L
The base end portion bent in a letter shape is attached to the attachment substrate 1 by joining or the like. On the other hand, a support pin 13 is vertically attached to the bobbin 11 at a position symmetrical with respect to the objective lens 10 about the support shaft 8. And the bobbin 11
Is held at the neutral point as described above by fitting and supporting the lower end of the support pin 13 in the fitting hole 14 formed in the holding portion of the elastic holding member 12.

As described above, the support shaft 8 and the elastic holding member 12 are provided.
A focusing drive coil 15 for slidingly displacing the bobbin 11 in the axial direction to drive the objective lens 10 in the focusing direction on the outer peripheral surface of the bobbin 11 supported by.
Further, a tracking drive coil 16 is provided which rotationally displaces the bobbin 11 in the direction around the axis to rotationally drive the objective lens 10 in the tracking direction. The focusing drive coil 15 is wound so as to generate a driving force for driving the bobbin 11 in the axial direction of the support shaft 8 in combination with the direction of the magnetic fields of the focusing magnets 4 and 4, and the tracking drive coil 16 is wound. Is wound so as to generate a driving force for driving the bobbin 11 around the support shaft 8 in combination with the direction of the magnetic field of the tracking magnets 6, 6.

On the lower surface side of the mounting substrate 1, when the objective lens driving device is mounted on the optical block, the optical axis of the objective lens 10 and the optical axis of the light beam transmitted through the optical system block may coincide with each other. As described above, the ring-shaped positioning adjusting member 17 for adjusting and positioning the mounting position of the objective lens driving device with respect to the optical block is mounted by the screw 18. The positioning adjustment member 17 includes the support shaft 8
When the objective lens driving device is attached to the optical system block, it is fitted eccentrically with respect to the optical system block. By rotationally adjusting the positioning adjustment member in the positioning recess, the objective lens and the optical axis of the light beam are aligned with each other.

In the objective lens driving device constructed as described above, a servo current corresponding to the error detection output in the focusing direction and the tracking direction, which is obtained by detecting the returning light beam reflected from the optical disk surface, is supplied to each drive coil. 1
5 and 16 are selectively supplied to drive the bobbin 11 in the axial direction of the support shaft 8 and the direction around the axis, whereby the objective lens 1
0 is moved and displaced in the focusing direction and the tracking direction, and the beam spot of the light beam focused on the signal recording surface of the optical disc is controlled so as to accurately follow and match the recording track of the optical disc.

[0010]

In the objective lens driving device constructed as described above, the bobbin 11 having the objective lens 10 mounted at the eccentric position is centered on the support shaft 8 provided at the shaft center. Since it is configured to rotate by sliding,
Does not have fixed support points. Therefore, resonance may occur when the bobbin 11 is driven and displaced in the focusing direction and the tracking direction, and the objective lens 10 cannot be moved and displaced according to the error detection output in the focusing direction and the tracking direction. There is a possibility that focusing on the signal recording surface of the optical disc and tracking scanning of the recording track cannot be performed.

Further, since the bobbin 11 is slidably displaced in the axial direction of the support shaft 8, so-called stick slip occurs during driving, and smooth movement displacement of the support shaft 8 in the axial direction cannot be realized.

Further, since the optical axis of the objective lens and the optical axis of the light beam are accurately aligned with each other, it is required that the support shaft 8 for supporting the bobbin 11 be attached with high precision, and the bobbin 11 is loose against the support shaft 8. In order to smoothly move without supporting, the dimensional accuracy of the shaft diameter of the support shaft 8 and the hole diameter of the insertion hole through which the support shaft 8 is inserted needs to be processed with high accuracy, and the processing is extremely difficult.

Furthermore, the above-mentioned objective lens driving device is
A positioning member 17 is mounted on the lower surface of the mounting substrate 1 to position the mounting position on the optical block.
The positioning member 17 and the bobbin 11 need to be mounted in two directions with the mounting substrate 1 interposed therebetween, which complicates the assembly process.

Therefore, according to the present invention, resonance does not occur during driving, responsiveness is high even with a servo current having a high frequency, durability against temperature change is provided, and accurate focus control and tracking control can be performed. An object is to provide an objective lens driving device.

A further object of the present invention is to provide an objective lens driving device which can reduce the number of parts, can be easily assembled and can be miniaturized.

[0016]

In order to achieve the above-mentioned object, an objective lens driving device according to the present invention has a bobbin to which an objective lens is attached, and a bobbin facing the outer peripheral surface of the bobbin on a substrate. A magnet provided and a coil provided at a position facing the magnet of the bobbin, and supplied with a drive current for driving the bobbin in an optical axis direction of the objective lens and a direction orthogonal to the optical axis direction; A pair of first and second members arranged above the substrate so as to be parallel to a direction orthogonal to the optical axis direction of the objective lens and supporting the bobbin at one end side so as to be displaceable in the optical axis direction of the objective lens. A second displacing member, a third displacing member provided with a hinge part, and rotatably supporting the bobbin around the hinge part in a direction orthogonal to the optical axis direction of the objective lens; Serial with the other end of the first and second displacement member is attached to the upper and lower respectively than one direction side,
A support member having the third displacement member integrally provided on the side surfaces of the first and second displacement members on the mounting direction side, the third displacement member being the same as the first displacement member. It is arranged between the second displacement member and the second displacement member so as to be parallel to the optical axis direction of the objective lens.

[0017]

In the objective lens driving device according to the present invention, when the servo signal in the focusing direction for driving the objective lens in the direction parallel to the optical axis of the objective lens is supplied to the coil, the bobbin to which the objective lens is attached is moved to the objective lens. The pair of first and second displacement members arranged in parallel to each other in the direction orthogonal to the optical axis direction of (1) is displaced to drive and displace in the direction parallel to the optical axis of the objective lens.

When a servo signal in the tracking direction for driving the objective lens in the direction orthogonal to the optical axis is supplied to the coil, the bobbin is centered around the hinge portion provided on the third displacement member. Drive displacement in a direction orthogonal to the optical axis of.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

The objective lens driving device according to the present invention is shown in FIG.
Further, as shown in FIG. 2, a magnetic circuit portion is formed on a mounting substrate 21 which is a mounting portion to an optical system block (not shown) in which a semiconductor laser as a light source for emitting a light beam and other optical parts are built. The first and second yokes 22 and 23 having a letter shape are attached so as to face each other. The yokes 22 and 23 are fitted into the positioning groove 24 provided on the mounting substrate 21 on the side of the connecting portions 22a and 23a, and the fitting recesses 25 and 2 provided on the lower surfaces of the connecting portions 22a and 23a.
Positioning projection 2 in which 6 is provided in the positioning groove 24
7 and 27 are fitted and attached (see FIG. 3), and the attachment direction and the attachment position with respect to the attachment substrate 21 are determined and fixed. On the inner side surfaces of the rising pieces 22b and 23b located outside the yokes 22 and 23,
The magnets 28 and 28 are arranged so as to be joined together.

The mounting board 21 is located at the center between the first and second yokes 22 and 23.
An optical window 29 through which a light beam emitted from a semiconductor laser built in the optical system block passes is opened. Further, mounting tongue pieces 30, 30 serving as fixing portions to the optical system block are formed on both sides of the mounting board 21. These mounting tongue pieces 30, 30 have screw insertion holes 3
1 and 31 are provided, and the mounting substrate 2 is fixed by fixing screws 32 and 32 which are inserted through these screw insertion holes 31 and 31.
1 is fixed to the optical system block.

The objective lens 33, which is arranged so as to face the optical disk which is the optical recording medium and focuses the beam spot of the light beam on the signal recording surface of the optical disk,
A cylindrical lens barrel 35 having a flange portion 34 on the outer periphery
It is attached to the bobbin 36 having a rectangular shape via. The bobbin 36 is made of synthetic resin, and has a fitting hole 37 formed in the center thereof, into which the lens barrel 35 is tightly fitted. Then, the lens barrel 35 is attached by fitting the lower end side thereof into the fitting hole 37. On the outer peripheral surface of the bobbin 36, a focusing drive coil 38 for obtaining a driving force for driving and displacing the objective lens 33 in a focusing direction which is a direction parallel to the optical axis of the objective lens 33, and the objective lens 33.
Four tracking drive coils 39 for obtaining a driving force for driving and displacing the optical disc in the radial direction of the optical disc in a direction orthogonal to the optical axis of the objective lens 33 are arranged so as to face the magnets 28, 28, respectively. There is.

Then, the focusing drive coil 3 is provided.
8 is wound in the circumferential direction of the bobbin 36 so as to generate a driving force for driving the objective lens 33 in the focusing direction in cooperation with the magnetizing directions of the magnets 28, 28. , The magnet 2
The bobbin 36 is wound in a square shape so as to generate a driving force for driving the objective lens 33 in the tracking direction in combination with the magnetizing directions of 8 and 28, and is provided over each corner portion of the bobbin 36.

The objective lens 33 is attached as described above, and the focusing and tracking drive coils 38,
The bobbin 36 provided with 39 is a pair of first and second displacing members that are fixedly mounted at their base ends to a supporting member 40 that is fixed to the mounting substrate 21 via the second yoke 23. 1 leaf spring 41a and 2nd leaf spring 41b
Supported by. These first and second leaf springs 41
The support member 40 to which a and 41b are fixed has a leaf spring mounting portion 42 having upper and lower end surfaces 42a and 42b parallel to each other and formed by molding synthetic resin or the like. On one side surface 42c of the second spring 42, which faces the second yoke 23, a continuous piece portion 43, which is continuous in the height direction of the leaf spring attachment portion 42 and constitutes a third displacement member, is provided. As shown in FIG. 2, a fitting piece 45 is integrally formed on the tip side of the continuous piece 43. This fitting piece 45 has a magnet 2 of the second yoke 23 on both sides.
By being fitted between a pair of L-shaped holding pieces 44, 44 provided facing each other on the outer side surface side of the rising piece to which 8 is joined, it is attached to and supported by the second yoke 23. .
The support member 40 thus mounted and supported on the second yoke 23 is separated from the mounting substrate 21, and is fixed to the mounting substrate 21 via the second yoke 23 fixed to the mounting substrate 21. The continuous piece 43 of the support member 40 is provided with a hinge portion 46 formed by thinning a part of the continuous piece 43 so as to be continuous in the height direction. By providing the hinge portion 46 in this way,
The objective lens 33 attached to the bobbin 36 can be displaced in the direction orthogonal to the optical axis about the hinge portion 46.

The first and second leaf springs 41a and 41b arranged in parallel with each other have base end portions 41a and 41a on the upper and lower end surfaces 42a and 42b of the leaf spring mounting portion 42 of the supporting member 40, respectively. It is fixedly installed. A fitting hole 48 is formed in each of the base end portions 41a, 41a so as to be fitted into a fitting protrusion 47 formed on each of the upper and lower end surfaces 42a, 42b of the leaf spring mounting portion 42 which are parallel to each other. .
Then, the leaf springs 41, 41 are attached by fitting the fitting holes 48 into the fitting protrusions 47. At this time, the fitting protrusion 47 is heated and crushed, and the first and second leaf springs 41a and 41b are fixed so that they are prevented from coming off the leaf spring mounting portion 42. The pair of first and second leaf springs 41a and 41b thus mounted are parallel to each other and to the surface of the mounting substrate 21.

The pair of first and second leaf springs 41a, 41a,
An opening 49 for adjusting the elastic force is provided in the central portion of 41b so that the second yoke 23 faces when attached to the leaf spring attaching portion 42.

The bobbin 36 has an upper and lower surface 51, which is a plane orthogonal to the optical axis of the objective lens 33, by bobbin mounting portions 50, 50 provided at the tip ends of the pair of first and second leaf springs 41a, 41b. , 52 are clamped and attached. The bobbin mounting portions 50, 50 are provided with a through hole 53 facing the objective lens 33 mounted on the bobbin 36 and a through hole 54 facing the optical window 29 opened in the mounting substrate 21, respectively. Around the perforations 53 and 54, there are formed fitting holes 56 into which the fitting projections 55 formed on the upper and lower surfaces 51 and 52 of the bobbin 36 fit. And
The bobbin 36 fits the fitting protrusions 55 into the fitting holes 56 and crushes the fitting protrusions 55 to prevent the bobbin from slipping out, thereby bobbins of the first and second leaf springs 41a and 41b. It is supported and fixed to the mounting portions 50, 50.

The bobbin 36 has first and second bobbins 36.
The yoke insertion holes 57 and 58 through which the inward rising pieces 22c and 23c, which face the rising pieces 22b and 23b to which the magnets 28 and 28 of the yokes 22 and 23 are joined, are formed, and the first and second yoke insertion holes 57 and 58 are formed. Riser 22 on the inner side of each yoke 22, 23 when supported by the leaf springs 41a, 41b of
c and 23c are inserted and fitted. The focusing and tracking drive coil 3 provided on the bobbin 36
8, 39 are magnets 28, 28 and yokes 22, 2
A predetermined magnetic gap is held and supported in the gap between the inner rising pieces 22c and 23c.

The lens barrel 35 holding the objective lens 33 attached to the bobbin 36 is fitted into the fitting hole 37 while the bobbin 36 is supported by the first and second leaf springs 41a and 41b. The flange portion 34 is attached by being locked to the smooth surface of the first leaf spring 41a, and the objective lens 33 is positioned in the optical axis direction.

The objective lens drive constructed as described above is
When a driving current is supplied to the focusing driving coil 38, a driving force in the direction of arrow F in FIG. Driven in the same direction. At this time, moments in directions opposite to each other act on the pair of first and second plate springs 41a and 41b that support the bobbin 36 and are parallel to each other.
If 41b having the same compliance is used, the moments cancel each other and move while maintaining the parallel state, and move the bobbin 36 in the direction parallel to the optical axis direction of the objective lens 33. Then, the focus control of the objective lens 33 that focuses the light beam on the signal recording surface of the optical disc is performed.

When a drive current is supplied to the tracking drive coil 39, a force in the direction of arrow T in FIG. 1 is generated by magnetic action from the direction of the current flowing in the coil 39 and the direction of the magnetic flux from the magnet 28. And bobbin 36
Hinge portion 46 of support member 40 supporting this bobbin 36
Driven in the same direction around. Then, the objective lens 33 is moved in a direction orthogonal to the optical axis direction parallel to the signal recording surface of the optical disc, and tracking control is performed.

In the above-described embodiment, the support member 40 is mounted by fitting the fitting piece 45 between the holding pieces 44, 44 provided on the second yoke 23.
4, the fitting piece 45 may be attached to the outer rising surface of the second yoke 23 by an adhesive or the like as shown in FIG.

Further, in the above embodiment, the support member 40 is used.
Is fixed to the mounting substrate 21 via the second yoke 23, but it may be mounted via a support shaft that is erected on the mounting substrate 21 as shown in the embodiments described below.

Below, the support shaft 60 is set up on the mounting substrate 21.
An embodiment in which the support member 40 is attached by using will be described. In addition, about the common part with the above-mentioned embodiment,
The same reference numerals are given and detailed description is omitted.

In the objective lens driving device shown in FIGS. 5 and 6, the support shaft 40 for fixing the support member 40 is planted on the mounting substrate 21 to which the first and second yokes 22 and 23 are mounted. The support shaft 60 is located and erected on the outer side of the second yoke 23 forming the magnetic circuit section. Then, the support member 4 fixed to the mounting substrate 21 via the support shaft 60.
0 is the objective lens 33 as shown in FIGS. 7, 8 and 9.
A pair of leaf springs 4 supporting the bobbin 36 to which the
The plate-shaped plate spring mounting portion 42 having upper and lower end surfaces 42a and 42b parallel to each other, to which the base end portions 41a and 41a of the plate springs 1 and 41 are fixed, and the second yoke 23 of the plate spring mounting portion 42 are opposed to each other. It is composed of a fixing portion 62 having a support shaft fitting hole 61 provided through a continuous piece portion 43 provided on one side surface so as to be orthogonal to the height direction.

The continuous piece 43 is a leaf spring mounting portion 42.
A hinge portion 46 is provided at the center position of the hinge portion and is continuous in the height direction and is partially thinned. Further, the support shaft fitting hole 6 on the lower end surface of the fixing portion 62.
At a position eccentric with respect to 1, the rotation adjusting member 64 of the optical axis aligning mechanism 63 for adjusting the alignment between the optical axis of the objective lens 33 and the optical axis of the light beam transmitted from the optical system block is provided. An engagement pin 66 that engages with the fitting recess 65 is provided in a protruding manner.

A bobbin 36 to which the objective lens 33 is attached
Pair of first and second leaf springs 41a, 41b supporting
The support member 40 to which is fixed is press-fitted into the support shaft 60 through the support fitting hole 61 formed in the fixing portion 62 and fixed to the mounting substrate 21.

On the mounting substrate 21, the objective lens 33 and the optical axis alignment mechanism 63 for aligning the optical axis of the light beam are provided as described above. This optical axis adjusting mechanism 63
A through hole 68 provided at a position eccentric to a fitting recess 67 that fits into a flange portion 60a formed at the base end of the support shaft 60.
Is attached by being inserted through a fixing screw 69 screwed to the mounting substrate 21, and is constituted by a rotation adjusting member 64 which is eccentrically rotated with respect to the support shaft 60. This rotation adjusting member 64
An engaging recess 65 is provided at one end opposed to the through hole 68, and an engaging pin 66 protruding from the support 40 is engaged with the engaging recess 65. A gear portion 70 is formed on the outer peripheral surface of the rotation adjusting member 64. Then, as shown in FIG. 10, when the gear portion 70 is rotated by the adjusting driver D, the support member 40 is rotated around the support shaft 60. A pair of first and second leaf springs 4 are attached to the support member 40.
The objective lens 33 attached to the bobbin 36 supported by 1a and 41b is rotated in the direction of arrow A in FIG. 10 to align the optical axis with the optical axis of the light beam transmitted from the optical system block. . Then, when the optical axis is aligned, the fixing screw 69 is tightened and the rotation adjusting member 64 is fixed to the mounting substrate 21, so that the objective lens 33 and the optical axis of the light beam are accurately aligned. The device is configured.

The objective lens drive constructed in this way is
Even if there is a variation in the processing accuracy of the hinge portion 46 and the optical axis of the light beam is displaced from the objective range 33, the variation in the processing accuracy of the hinge portion 46 is absorbed and the optical axis is aligned accurately. It becomes possible.

In the above embodiment, the support member 40
Is attached by press-fitting to the support shaft 60, but a retaining ring may be fitted to the tip of the support shaft 60 to prevent the support shaft from coming off.

Further, instead of the support shaft 60, a long screw may be inserted into a support shaft fitting hole 61 formed in the fixing portion 62, and the support member 40 may be attached by this screw.

Furthermore, the processing accuracy of the hinge portion 46 provided on the support member 40 can be sufficiently obtained, and the objective lens 33 can be obtained.
The support member 40 to which the pair of first and second leaf springs 41a and 41b for supporting the bobbin 36 to which is attached is fixed is the support shaft 6
If the objective lens 33 and the optical axis of the light beam can be aligned only by fixing the optical axis to 0, it is not necessary to provide the optical axis alignment mechanism 63.

[0043]

As described above, in the objective lens driving device according to the present invention, the bobbin to which the objective lens is attached is made parallel to the optical axis of the objective lens by the first and second displacement members arranged in parallel with each other. Since it is movably supported in any direction, the objective lens can be accurately moved in a direction parallel to the optical axis direction without causing an inclination of the optical axis, and smooth movement is realized. Furthermore, since the bobbin is rotatably supported by the third displacement member provided with the hinge portion in the direction orthogonal to the optical axis of the objective lens,
Resonance hardly occurs during driving, and stable tracking operation can be realized.

Particularly, the first and second displacement members for supporting the bobbin so as to be displaceable in the optical axis direction of the objective lens are opposed to each other and are parallel to the same direction, and are attached to and supported by the support member so that the bobbin is an objective. Since the third displacement member, which is rotatably supported in the direction orthogonal to the optical axis direction of the lens, is disposed between the first displacement member and the second displacement member, each displacement member is arranged. The space of the arrangement is saved, and the miniaturization of the device itself is achieved.

Further, a magnet for generating a driving force for driving the bobbin in the optical axis direction of the objective lens and in a direction orthogonal to the optical axis direction together with the driving current supplied to the coil provided on the bobbin is provided on the outer circumference of the bobbin. Since the bobbin is arranged on the surface side, the bobbin can be reduced in size and weight. Since the bobbin is smaller and lighter,
In addition to contributing to further downsizing of the device itself, driving can be performed with a small driving current, and efficient driving displacement of the objective lens is realized.

Further, a third displacing member is integrally provided on one side surface of the support member to which the other ends of the first and second displacing members are attached, and is located between the first and second displacing members. Since the objective lens is arranged in the direction of the optical axis, the radius of rotation when the lens is rotationally displaced in the direction orthogonal to the optical axis direction can be reduced, and the apparatus itself can be further downsized.

Furthermore, the first and second displacement members are
Since the support members are extended in parallel with each other in the same direction, the expansion and contraction directions and the expansion and contraction amounts due to temperature changes are substantially the same, so that the objective mounted on the bobbin supported by the first and second displacement members is mounted. The inclination of the optical axis of the lens and the deviation of the optical axis are prevented, and further the positional deviation between the magnet and the coil of the bobbin is prevented, so that the driving displacement of the objective lens can be performed with high accuracy.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an objective lens driving device according to the present invention.

FIG. 2 is an exploded perspective view of the objective lens driving device.

FIG. 3 is a side sectional view of the objective lens driving device.

FIG. 4 is a perspective view showing another example of a mounting state of a support member on a yoke.

FIG. 5 is a perspective view showing another embodiment of the present invention.

FIG. 6 is a perspective view showing an assembled state of another embodiment of the present invention.

FIG. 7 is a front view showing a supporting member used in another embodiment of the present invention.

FIG. 8 is a plan view of the support member.

FIG. 9 is a side view of the support member.

FIG. 10 is a plan view showing an optical axis position adjustment state of an objective lens in another example of the present invention.

FIG. 11 is a perspective view showing a conventional objective lens driving device.

FIG. 12 is a side sectional view of the conventional objective lens driving device.

[Explanation of symbols]

 21 Mounting Substrate 22 First Yoke 23 Second Yoke 28 Magnet 33 Objective Lens 36 Bobbin 38 Focusing Drive Coil 39 Tracking Drive Coil 40 Supporting Member 41a First Leaf Spring 41b as a First Displacement Member 41b Second Displacement Member Second leaf spring 43 that is a continuous displacement piece that is a third displacement member 45 fitting piece 46 hinge portion

Front page continued (72) Inventor Kenji Shintani 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (1)

[Claims] 1. A bobbin to which an objective lens is attached, a magnet provided on a substrate so as to face an outer peripheral surface of the bobbin, and a magnet provided on the bobbin so as to face the magnet. A coil to which a drive current for driving the bobbin is supplied in the optical axis direction and in a direction orthogonal to the optical axis direction, and is arranged above the substrate so as to be parallel to the direction orthogonal to the optical axis direction of the objective lens. A pair of first and second displacement members for supporting the bobbin at one end side so as to be displaceable in the optical axis direction of the objective lens, and a hinge portion are provided, and the bobbin is centered around the hinge portion. A third displacing member rotatably supporting the objective lens in a direction orthogonal to the optical axis direction, and the other end sides of the first and second displacing members are respectively attached vertically from one direction side. The first and second
A supporting member integrally provided with the third displacing member on a side surface of the displacing member on the mounting direction side, the third displacing member including the first displacing member and the second displacing member.
The objective lens driving device, which is located between the displacing member and the displacing member and is parallel to the optical axis direction of the objective lens.