JP2003222503A - Sensor for actuator of optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize the whole actuator equipped with a sensor by arranging efficiently the sensor for detecting the position or the moving speed of an optical sensor operated by the actuator. <P>SOLUTION: This sensor for the actuator of the optical element is equipped with an objective lens 100 for projecting first light L<SB>1</SB>to the object position and acquiring a light spot, support driving mechanisms 131-134, 151-154, 140a, 140b, 142 having a holder 110 for holding the lens 100 and supporting and driving the holder 110, a shielding bar 116 provided on the holder 110, and an LD 163 for receiving second light L<SB>2</SB>from an LED 164 through the shielding bar 116. The sensor is constituted so that the first light L<SB>1</SB>and the second light L<SB>2</SB>cross mutually. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to recording and / or reproducing information on an optical recording medium such as a magneto-optical disk drive, a write-once disk drive, a phase change disk drive, a CD-ROM, a DVD and an optical card. The present invention relates to an actuator that drivably supports an optical element such as an objective lens used in an information recording / reproducing apparatus, a coupling lens for an optical fiber used in optical communication, or an objective lens of a scanning microscope.

[0002]

2. Description of the Related Art In an actuator for an optical pickup used in an optical device such as the above information recording / reproducing device, an objective lens which is an optical element is supported so as to be drivable in two directions of a focus direction and a tracking direction which are orthogonal to each other. It is necessary to accurately position the light spot of (1) on the recording track of the recording medium. Therefore, as an actuator for supporting the optical element so as to be able to be driven in two directions, various actuators having high driving sensitivity have been proposed for the purpose of improving recording density and access speed.

For example, Japanese Utility Model Publication No. 8-7305 discloses that
An actuator as shown in FIGS. 10 and 11 has been proposed. This actuator fixes a holder 20 holding the objective lens 10 to a spring holder 40 via four springs 30, and the spring holder 40 is fixed to the base 4
It is attached to 2.

The holder 20 is provided with one focus coil 21 and one tracking coil 22 on both side surfaces thereof (side surfaces facing each other in the tangential direction Z orthogonal to the focus direction X and the tracking direction Y). 21 to the tracking coil 22 and the outer yoke 42a integrated with the base 42.
An effective magnetic field is directed from the magnet 43 provided at the outer yoke 42a and the inner yoke 42b.

Therefore, when a current is applied to the focus coil 21 and the tracking coil 22, the actuator drives the holder 20 in the focus direction X and the tracking direction Y by the interaction with the magnetic field generated by the magnet 43, so that the mirror 24 moves. The light spot of the objective lens 10 obtained by the reflected light can be accurately positioned on the recording track of the recording medium.

In this case, the position and the moving speed of the objective lens 10 are determined by the light shielding bar 20f provided on the side surface of the holder 20.
Is arranged between the LED (light emitting diode) 44 and the PD (photodiode) 45 to form a sensor, and the position and the moving speed of the light shielding bar 20f are detected from this sensor.

[0007]

However, it has been clarified that such a conventional sensor for detecting the position and the moving speed of the objective lens 10 has the following inconveniences.

In the above sensor, since the light shielding bar 20f is arranged on the side surface of the holder 20, a wide space is required around the objective lens 10. Therefore, for example, in the case of a sensor having such a configuration, this sensor interferes with the spindle motor that drives the recording medium, so that the objective lens 1
There arises a problem that 0 cannot be brought close to the spindle motor. Further, for example, since it is necessary to arrange the light incident on the objective lens so as not to interfere with the sensor, there is a problem that the actuator becomes large.

The present invention has been made to solve the above-mentioned problems, and by efficiently disposing a sensor for detecting the position or moving speed of an optical element operated by an actuator, It is an object of the present invention to reduce the size of the entire actuator including such a sensor.

[0010]

Therefore, an actuator sensor for an optical element according to the first aspect of the present invention includes an optical element that projects a first light at a target position to obtain a light spot, and an optical element that holds the optical element. Of a support drive mechanism having a holder for supporting and driving the holder, a light projection unit provided in the holder, and a light receiving element for receiving the second light from the light source via the light projection unit. In the actuator sensor, the first light and the second light are configured to intersect with each other.

A sensor for an actuator of an optical element according to a second aspect of the invention is characterized in that, in the first aspect of the invention, the light projecting portion is provided below the holder.

A sensor for an actuator of an optical element according to a third aspect of the present invention is the sensor according to the first aspect of the present invention, wherein the light source and the light receiving element are arranged at positions sandwiching the holder.

[0013]

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

FIG. 1 is a perspective view showing a main part of a recording / reproducing apparatus for an optical disc according to a first embodiment of the present invention. 2 to 4 are a top view showing the entire first embodiment from the upper side, a cross-sectional view showing FIG. 2 from the tracking direction, and an exploded perspective view of FIG. 2, respectively.

This recording / reproducing apparatus is a recording / reproducing apparatus for an optical disc 1 (see FIG. 3) of a phase change recording system, in which an objective lens 100, which is an optical element, has a first direction (focus direction) X and a second direction orthogonal to each other. 2 directions (tracking direction)
It is supported so that it can be driven in two Y directions. As the optical disc 1, an existing one whose recording surface 1F is covered with a thin cover glass 1C of 0-0.1 (mm) is used.

As shown in FIGS. 3 and 4, the objective lens 100 has a high NA of 0.7 to 0.9, and the upper end of the holder 110 whose central axis O ₁ coincides with the optical axis of the objective lens 100. It is fixedly held in the mounting hole formed in. The holder 110 also fixedly holds the chromatic aberration correction lens 120 at its lower end, and the chromatic aberration correction lens 120
While functioning as a balancer in the focus direction X of the objective lens 100, the objective lens 100 functions as a balancer in the focus direction X of the chromatic aberration correction lens 120. In this case, the holder 110 does not need an extra balancer.

As shown in FIG. 4, the holder 110 includes two first mounting surfaces 111a and 111b arranged to face the holder 110 in the tracking direction Y and a third direction (which is orthogonal to the focus direction X and the tracking direction Y). Two second mounting surfaces 112a, 112 arranged to face the holder 110 in the tangential direction) Z.
b and.

The first mounting surface 111a has two protrusions protruding along the tracking direction Y, and the first flat coil (hereinafter referred to as the focus coil) 131, which is the first driving means, is formed by these protrusions. The first attachment surface 11 is positioned on the first attachment surface 111a.
It is bonded and fixed in parallel to the entire surface of 1a. In addition,
Similarly, the first mounting surface 111b also has a tracking direction Y.
Two protrusions (not shown) are formed to project along the first and second protrusions, which are the first driving means.
With the flat coil (hereinafter referred to as the focus coil) 132 positioned on the first mounting surface 111b, the first coil
It is adhered and fixed in parallel to the entire surface of the mounting surface 111b.

The second mounting surface 112a has two protrusions protruding along the tangential direction Z, and the second flat coil (hereinafter referred to as a tracking coil) 133 which is the first driving means by these protrusions. Is fixed to the second mounting surface 112a in parallel with the entire surface of the second mounting surface 112a. Similarly, the second mounting surface 112b also has two protrusions (not shown) protruding along the tangential direction Z, and these protrusions form a second flat coil (hereinafter, referred to as a first drive unit). Tracking coil)
In a state in which 134 is positioned on the second mounting surface 112b, it is adhesively fixed in parallel to the entire surface of the second mounting surface 112b.

That is, the focus coils 131 and 132
And the tracking coils 133 and 134 are the holder 1
As a first drive means for driving the holder 10, the holder 110
The first mounting surface 111 parallel to the central axis O ₁ of the objective lens 100, that is, four total focusing directions X provided so as to surround the optical axis of the objective lens 100 and face each other.
a, 111b and second mounting surfaces 112a, 112b
Mounted parallel to.

Further, the holder 110 is integrally provided with two fixing parts 115 extending along the focus direction X at two positions on the side of the tracking coil 133, and the fixing parts 115 respectively have springs 140a and 140b which are supporting members. One end of is glued and fixed. The springs 140a and 140b are
A thin plate made of beryllium copper having a thickness of about 0.05 (mm) is edging-processed, and springs 140a, 140
The intermediate portion of b surrounds the periphery of the objective lens 100, and together with the base 141 described later, the focus coils 131, 1
It is located so as to sandwich 32. And spring 140
The other end of each of a and 140b has a spring holder 14
Two spring fixing portions 142a and 142b, which are integrally formed with the spring holder 142, are adhesively fixed to the upper and lower ends of the spring holder 2.

The spring holder 142 is bonded and fixed as a first fixing member in a state of being positioned with respect to an outer peripheral surface 141w ₁ of a side wall 141w of a base 141, which will be described later, by two bosses formed on its mounting surface 142f. ing.

As a result, the holder 110 holding the objective lens 100, the focus coils 131, 132 and the tracking coils 133, 134 are movably supported by the springs 140a, 140b as movable parts.

As shown in FIG. 2, the base 141 has a substantially cylindrical shape in which an iron plate having a thickness of 0.6 (mm) is drawn and formed integrally with a side wall 141w surrounding the movable portion. While the focus magnets 151 and 152, which are the second drive means polarized in the focus direction X, are bonded to the inner peripheral surfaces 141w ₂ of the side walls 141w that are arranged opposite to each other in the tracking direction Y,
Tracking magnets 153 and 154, which are second driving means magnetized in two poles in the tracking direction Y, are bonded to the inner peripheral surfaces 141w ₂ of the side walls 141w that are arranged to face each other in the tangential direction Z. In this case, it is convenient to use a two-pole magnetized magnet as the magnetic field generating means because it is possible to easily generate a magnetic field of a required magnitude.

That is, the focus magnet 151
Referring to FIG. 4, the magnetic pole of (152) faces the two working sides 131a and 131b (132a and 132b) of the focus coil 131 (132) extending in the tangential direction Z, and the tracking magnet 15
3 (154) has a tracking coil 133 (1
34) two action sides 13 extending in the focus direction X
It faces 3a and 133b (134a and 134b).

As shown in FIG. 3, the base 141 is integrally formed at its lower end with a spherical surface portion 141f for adjusting the inclination, and this spherical surface portion 141f is formed on the upper surface of the carriage 160 which is the second fixing member. The inclined conical surface 160f is inclinablely contacted. This allows the base 141
Is adjusted with respect to the carriage 160, and then the inner peripheral surface 160w of the side wall 160w provided on the carriage 160 is adjusted.
It is fixed to 1 via an adhesive 170. A reflection mirror 161 is housed in the conical surface 160f of the carriage 160, as shown in FIG.

Further, the base 141 is, as shown in FIG.
The sensor holder 162 is provided on the outer surface in the tracking direction Y.
Is fixed. The sensor holder 162 includes a PD (photodiode) 163 and an LED (light emitting diode) 164 having light-receiving surfaces divided in two in the tracking direction Y, at both ends facing each other in the tangential direction Z.

In the recording / reproducing apparatus of this embodiment, the light L1 from the laser 200 is incident on the hologram plate 201 as shown in FIG. 4, and then the 0th-order diffracted light is incident on the collimator lens 202 to form a parallel light L1. Becomes The parallel light L1 is reflected by the reflection mirror 161 fixed to the carriage 160, and the reflected light is passed through the chromatic aberration correction lens 120 as shown in FIG.
Recording surface 1F of the optical disc 1
A light spot can be connected to. Further, in the present embodiment, the reflected light from the recording surface 1F of the optical disc 1 is made to follow the reverse optical path to the objective lens 100, the chromatic aberration correction lens 120, and the reflection mirror 161, and is made incident on the hologram plate 201, and is reflected by the hologram plate 201. The first-order diffracted light is received by the light receiving element 203.
Of tracking error,
Focus error detection and RF signal detection can be performed. Since various optical systems have been proposed, detailed description thereof will be omitted.

Here, FIGS. 5 and 6 respectively show the relationship between the first light L1 used for recording / reproducing of the optical disc 1 and the second light L2 used for detecting the position of the objective lens 100 in the focus direction X. Alternatively, it is an operation diagram shown from the tangential direction Z.

The first light L1 is the light that is incident on the mirror 161 from the laser 200 through the hologram plate 201 and the collimator lens 202, and the second light L2 is also present.
Is the light incident on the PD 163 from the LED 164.

The second light L2 emitted from the LED 164.
5 is projected onto the light-shielding bar 116, which is a light projecting unit arranged at the lower end of the holder 110, as shown in FIGS.
Is incident on the light receiving part of. At this time, when the holder 110 moves in the tracking direction Y integrally with the objective lens 100, the light blocking bar 116 also moves in the tracking direction Y, so that the light receiving surfaces 163 a, 1 divided into two on the PD 163.
The position of the objective lens 100 in the tracking direction Y can be detected by taking the difference between the output signals of 63b.

However, in this recording / reproducing apparatus, the first light L1 and the second light L2 are arranged so as to intersect each other at right angles, as shown in FIGS. In the case of the present embodiment, the light shielding bar 116 is provided below the holder 110, and the light shielding bar 116, P is provided below the holder 110.
Since the D163 and the LED 164, the laser 200, the hologram plate 201, the collimating lens 202, and the mirror 161 can be arranged on substantially the same plane, the light shielding bar 116, the PD 163, and the sensor including the LED 164 are efficiently arranged below the holder 110. be able to.

Therefore, according to the present embodiment, the LED 164
The light L2 emitted from the objective lens 10 operated by the actuator is arranged so as to intersect the light L1 incident from the laser 200 on the reflection mirror 161 at a right angle.
By efficiently disposing the sensor for detecting the position of 0 or the moving speed, it is possible to reduce the size of the entire actuator including such a sensor.

Particularly, when the light shielding bar 116 is provided on the lower side of the holder 110, the light shielding bar 116, the PD 163 and the LED 164, the laser 200, the hologram plate are provided on the lower side of the holder 110 only by making a simple design change. The 201, the collimating lens 202, and the mirror 161 can be arranged on substantially the same plane. The shape of the light shielding bar 116 is not limited to the rod shape, and various shapes can be adopted.

Here, a method of finely adjusting the objective lens 100 will be described.

First, when the objective lens 100 is finely adjusted in the focus direction X, the focus coils 131 and 13 are used.
Power is supplied to 2 via springs 140a and 140b. At this time, the two working sides 131a of the focus coil 131,
The same force cooperating with the magnetic fields from the focus magnets 151 and 152 is generated along the focus direction X on the two action sides 132a and 132b of the 131b and the focus coil 132, respectively, so that the holder 110 moves in the focus direction X. By driving along, the objective lens 100 can be finely adjusted in the focus direction X.

Next, when finely adjusting the objective lens 100 in the tracking direction Y, the tracking coil 133,
Power is supplied to 134 via springs 140a and 140b. At this time, the working side 133a of the tracking coil 133,
133b and working edge 13 of tracking coil 134
Since the same force cooperating with the magnetic fields from the tracking magnets 153 and 154 is generated along the tracking direction Y in each of 4a and 134b, the holder 110 is driven along the tracking direction Y and the objective lens 100 is driven.
Can be finely adjusted in the tracking direction Y.

In addition, in the present embodiment, the effects as listed below can be obtained also in the configuration around the holder 110.

First, the holder 110 is respectively flattened on the first mounting surfaces 111a and 111b and the second mounting surfaces 112a and 112b provided on the holder 110 so as to surround the optical axis of the objective lens 100 which coincides with the central axis O _1. The focus coils 131, 132 and the tracking coils 133, 134 in the shape of a circle are respectively attached to the first mounting surface 1.
11a, 111b and second mounting surfaces 112a, 11
2b mounted parallel to the focus coil 13
1, 132 and tracking coils 133, 134 are used as magnetic field generation means for directing magnetic fields to focus magnets 151, 152 and tracking magnets 15.
3, 154 are associated with each other. In this case, the first
Mounting surfaces 111a, 111b and second mounting surface 1
12a and 112b, focus coils 131,
A sufficient space for disposing the 132 and the tracking coils 133 and 134 can be ensured.

Further, the holder 110 has driving coils 131 to ₁ on substantially the entire outer peripheral surface surrounding the central axis O _1.
By arranging 34, the useless empty space around the holder 110 is minimized, and the holder 110 is efficiently used.
Further, focus driving coils 131 and 132 and magnets 151 and 152, and tracking driving coils 133 and 134 and magnets 153 and 154.
Since and are not arranged on the same plane but are arranged on the respective separate mounting surfaces 111a, 111b, 112a, 112b which are perpendicular to each other, a large coil and magnet can be arranged on each.

That is, the focus coils 131 and 132
Since the tracking coils 133 and 134 can be set to have large outer dimensions, the respective action sides 131a, 131b, 132a, 132b, 133 are actuated.
a, 133b, 134a, and 134b can be increased in length and volume, and the focus magnets 151 and 152 and the tracking magnet 1 corresponding to the coils can be increased.
Since 53 and 154 can also be made large according to the coil, the objective lens 100 can be driven with high sensitivity in two directions of the focus direction X and the tracking direction Y.

Moreover, the focus coil 131 (13
2) corresponds to the focus magnet 151 (152), and the tracking coil 133 (134) corresponds to the tracking magnet 153 (154). Therefore, the magnetic field from the focus magnet 151 (152) and the tracking magnet 153 (154) The magnetic fields that generate different forces, such as the magnetic field of, do not interfere with each other. Therefore, for example, when finely adjusting the objective lens 100 in the focus direction X, the focus coil 131 (1
32) Even if a current is applied to the tracking magnet 153
Since the magnetic field acting from (154) to the focus coil 131 (132) is very small, the unwanted objective lens 1
The movement of 00 can be prevented.

Further, the focus coil 131 (132)
The tracking coil 133 (134) is flattened, and the flat surface is fixed to the holder 110.
111b and the second mounting surfaces 112a, 112b are mounted parallel to each other, so that the rigidity of the focus coil 131 (132) and the tracking coil 133 (134) mounted on the holder 110 is significantly increased, and the coil itself is deformed. The resonance frequency becomes very high. Further, the holder 110 itself has a rectangular block shape and high rigidity, and the central opening is reinforced by the objective lens 100 and the chromatic aberration correction lens 120, and the outer peripheral part is reinforced by the flat coil, so the rigidity is high, The resonance frequency also becomes high.

The magnetism generating means constitutes an open magnetic circuit having no yoke forming a magnetic gap, which is composed of the focus magnets 151 and 152 and the tracking magnets 153 and 154 which are magnetized in two poles. In this case, since it is not necessary to provide the holder 110 with an opening for disposing the yoke, the rigidity of the holder 110 can be increased by the rigidity of the opening.

The support member that drivably supports the holder 110 with respect to the base 141 is the focus coil 13
Springs 140a, 1 arranged so as to sandwich 1, 132
Since it is 40b, the width of the holder 110 in the tracking direction can be set small without increasing the width of the supporting member.

Further, the base 141 is of a cylindrical shape, and since there is no inner yoke that directly faces the focus magnet and the tracking magnet, a cantilever-shaped yoke or the like is not required, so that the rigidity of the base 141 is increased. be able to.

7 and 8 are a partial cross-sectional view showing a part of the recording / reproducing apparatus for an optical disk according to the second embodiment of the present invention from the upper side and a partial cross-sectional view showing the apparatus from the side, respectively. Further, FIG. 9 is an enlarged view of a main part showing a region A of FIG. 7. In the following embodiments, the above-mentioned first
The same parts as those in the second embodiment have the same reference numerals and the description thereof will be omitted.

Similar to the first embodiment, this recording / reproducing apparatus is a recording / reproducing apparatus for the optical disk 1 of the phase change recording system, in which the objective lens 300 is perpendicular to the focus direction X.
And, it is supported so as to be drivable in two directions of the tracking direction Y.

The holder 310 has a tangential direction Z.
2 has two mounting surfaces 311a and 311b arranged to face the holder 310, and two tracking coils 331 and one focus coil 332 are adhesively fixed to these mounting surfaces 311a and 311b, respectively.

In the holder 310, one ends of springs 340a and 340b, which are supporting members, are fixed. Spring 34
The intermediate portions of 0a and 340b extend along the outside of the holder 310 and are positioned so as to sandwich the holder 310. The other ends of the springs 340a and 340b are fixed to the fixing member 350 at two positions in the vertical direction, that is, at a total of four positions.

Further, the fixing member 350 includes a holder 310.
A magnet 360 is fixed via a yoke 370 at a position facing the tracking coil 331 and the focus coil 332 attached to the.

As a result, the holder 310 holding the objective lens 300, the tracking coil 331 and the focus coil 332 serve as a movable part and the spring 340.
a and 340b are drivably supported.

The holder 310 is provided with openings 312 and 313 as light projecting portions on both sides in a direction oblique to the tracking direction Y by about 45 degrees, and fixed to the fixing member 350 on the outside thereof. An LED (light emitting diode) 351 and a PD (photodiode) 352 are arranged. Note that the LED 351 has a second light L2.
The PD 352 is a light source for emitting the second light L
It has a light-receiving surface divided into two along the tangential direction Z for receiving 2.

Second light L2 emitted from the LED 351
After passing through the opening portion 312 formed in the holder 310, the light becomes larger than the opening area of the opening portion 313, and a part of the light passes through the opening portion 313 and the PD 352.
Is incident on. At this time, when the holder 310 moves integrally with the objective lens 300 in the tracking direction Y, as shown in FIG. 9, the opening 313 also moves in the tracking direction Y and comes to the position of the reference numeral 313 'shown by the broken line. Three
The second light L2 (out) that has passed through 13 at an angle of 45 degrees also moves in the tracking direction Y to reach the position indicated by the symbol L2 (out) 'shown by the broken line. Therefore, the position of the objective lens 300 in the tracking direction Y can be detected by calculating the difference between the output signals of the two light receiving surfaces 352a and 352b on the PD 352.

However, in this recording / reproducing apparatus, the first light L1 and the second light L2 are arranged so as to intersect each other at right angles, as shown in FIG. In this case, the holder 3
LED351 and PD352 are arrange | positioned in the position which sandwiches 10, and holder 310, LED351 and PD35 are arrange | positioned.
2 can be arranged almost on the same plane, the openings 312,
A sensor including 313, the LED 351 and the PD 352 can be efficiently arranged around the holder 310.

Therefore, according to the present embodiment, as in the first embodiment, the light L2 emitted from the LED 351 is arranged so as to intersect the light L1 entering the reflection mirror 161 from the laser 200 at a right angle, and is operated by the actuator. By efficiently disposing the sensor for detecting the position or the moving speed of the objective lens 300, it is possible to reduce the size of the entire actuator including such a sensor.

In particular, in this embodiment, the optical axis of the sensor (second light L2) is arranged obliquely with respect to the tracking direction Y. Therefore, when the drive system such as the magnet and the coil is arranged in the tangential direction Z with respect to the holder 310 as in the present embodiment, even if the sensor is arranged in the space existing in the tracking direction Y of the holder 310. The position and the moving speed of the objective lens 300 in the tracking direction Y can be detected by this sensor.

In addition, in the present embodiment, as shown in FIG. 9, tapered surfaces 313t1 and 313t2 that extend outward of the holder 310 are formed in the opening 313. In this case, the LEDs 351 of the tapered surfaces 313t1 and 313t2
The shape of the light incident on the PD 352 is determined by the side edge shape. Therefore, it is easy to set the shape of light on the PD 352. The holes of the openings 312 and 313 can adopt various shapes such as a circle and a polygon.

This embodiment can also be used in combination with the first embodiment, and the focus direction X
Alternatively, one of the tracking directions Y may be driven by a moving coil and the other may be driven by a moving magnet. Not only the focus coils 131 and 132, but also the tracking coils 133 and 134 or the focus coils 131 and 132 and the tracking coil 1
Both 33 and 134 may be capable of controlling the direction of the current flowing through the coil.

The above description merely shows the preferred embodiments of the present invention, and those skilled in the art can make various modifications within the scope of the claims. For example, in the first and second embodiments, the center axis O _{1 of the} holder is aligned with the optical axis of the objective lens 100 (300) so that fine adjustment of the objective lens 100 (300) is facilitated. The central axis O _{1 of the} holder is not necessarily the objective lens 100 (30
It is not necessary to match the optical axis of 0).

Although the magnets magnetized with two poles are opposed to each other on the two sides of the focus coil and the tracking coil, the single pole magnet may be opposed to only one side.
Further, in the support drive mechanism, the holder 110 (31
The support method of 0) is not limited to a leaf spring, and may be, for example, a wire having a circular cross section, a hinge made of a synthetic resin such as plastic, or the like, and various methods can be used. Further, the holder 110 (31
The driving method of 0) is not limited to the coil or the magnet, and various driving methods such as driving using a piezoelectric element and electrostatic driving can be used.

The light source and the light receiving element constituting the sensor are also
An LD (laser diode) may be used instead of the LED (light emitting diode), and a PSD (semiconductor position detector) may be used instead of the PD (photodiode).

The mounting surfaces 111a, 111b, 112a, 112b (31) provided on the holder 110 (310)
1a, 311b) is not limited as long as it is arranged so as to surround the central axis O ₁ of the holder 110 (310) so as to generate an equal force in the same direction on the two focus or tracking coils or the two focus or tracking magnets. The focusing direction X or the tracking direction Y need not be opposed to each other.

For this reason, in the present embodiment, the actuator of the objective lens used in the recording / reproducing apparatus for the optical disc is exemplified, but the optical element is not limited to the objective lens, but may be a collimator lens or an LD (laser diode). However, the device is also applicable to an actuator of a collimating lens for coupling with a fiber of an optical communication device.

[Brief description of drawings]

FIG. 1 is a perspective view showing a recording / reproducing apparatus for an optical disc according to a first embodiment of the present invention.

FIG. 2 is a top view showing the entire first embodiment from the upper side.

FIG. 3 is a cross-sectional view showing FIG. 2 from the tracking direction.

FIG. 4 is an exploded perspective view of the first embodiment.

FIG. 5 is a first light L1 used for recording / reproducing an optical disk and a second light L2 used for detecting the position of the objective lens.
FIG. 7 is an operation diagram showing the relationship between and in the focus direction X.

FIG. 6 is a first light L1 used for recording / reproduction of an optical disc and a second light L2 used for detecting the position of the objective lens.
FIG. 11 is an operation diagram showing a relationship with and from the tangential direction Z.

FIG. 7 is a partial cross-sectional view showing the recording / reproducing apparatus for an optical disc according to the second embodiment of the present invention from the upper side.

FIG. 8 is a partial cross-sectional view showing a recording / reproducing apparatus for an optical disc according to a second embodiment of the present invention from a side surface.

9 is an enlarged view of a main part showing a region A of FIG.

FIG. 10 is a perspective view showing an actuator of an optical element according to a conventional technique.

FIG. 11 is an exploded perspective view of the above conventional technique.

[Explanation of symbols]

1 Optical Disc 100 Objective Lens 110 Holders 111a, 111b First Attachment Surfaces 112a, 112b Second Attachment Surface 115 Fixed Part 116 Light-shielding Bar (Light Projection Part) 120 Chromatic Aberration Correction Lenses 131, 132 Focus Coils 133, 134 Tracking Coils 140a, 140b Spring 141 Base 141f Spherical part 141w Side wall 141w ₁ Outer peripheral surface 141w ₂ Inner peripheral surface 142 Spring holders 142a, 142b Spring fixing parts 151, 152 Focus magnet 153, 154 Tracking magnet 160 Carriage 160w Side wall 160w ₁ Inner peripheral surface 161 Reflecting mirror 162 Sensor Holder 163 PD (photo diode) 164 LED (light emitting diode) 170 Adhesive 200 Laser 201 Hologram plate 202 Collimator lens Reference numeral 203 Light receiving element 241 Base 241w Side wall 241w ₁ Outer peripheral surface 241w ₂ Inner peripheral surface (side surface of movable part) 300 Objective lens 310 Holders 311a, 311b Attachment surfaces 312, 313 Openings 331 Focus coil 332 Tracking coils 340a, 340b Spring 350 fixed part 351 LED (light emitting diode) 352 PD (photo diode) 360 Magnet 370 Inner yoke L1 First light L2 Second light

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2F065 AA03 AA06 CC22 DD02 EE08                       FF02 FF48 GG04 GG07 GG13                       HH15 JJ01 JJ05 JJ18 LL04                       LL10 LL12 LL42 LL51 NN20                 2H044 DA01 DB00 DC01 DE06                 5D118 AA01 AA13 BA01 CF00

Claims (3)

[Claims] 1. An optical element for projecting a first light to a target position to obtain a light spot, a support drive mechanism having a holder for holding the optical element and supporting and driving the holder, and the holder provided on the holder. In an actuator sensor of an optical element including a light projection unit and a light receiving element that receives the second light from the light source via the light projection unit, the first light and the second light may intersect with each other. A sensor for an actuator of an optical element, which is configured as described above. 2. The sensor for an actuator of an optical element according to claim 1, wherein the light projection unit is provided below the holder. 3. The actuator sensor for an optical element according to claim 1, wherein the light source and the light receiving element are arranged at positions sandwiching the holder.