JPS61180943A - Optical system driver - Google Patents

Abstract

PURPOSE:To attain a 2-dimensional high-speed shift of an optical system by setting a pair of needles so that they can move independently along the direction of a line connecting both needles, and connecting the end of a coupling member extending obliquely to each needle together with the optical system supported by the other end of the coupling member, respectively. CONSTITUTION:When the DC current of the same direction are flowed to coils 22 and 24, these coils receive the force in the same direction X1-X2 owing to an interaction with a magnetic field produced by a magnet 18. Both needles 2 and 4 are guided by a guide member 6 and moved in the same direction. While an objective lens 16 is moved only in the tracking direction. When the reverse DC currents are flowed to both coils 22 and 24, these coils receive the reverse force in the direction X1-X2 owing to the magnetic field of the magnet 18. Then the needles 2 and 4 are guided by the member 6 up to the positions where they match with the elastic force produced by elastic matters 11 and 13 of coupling members 10 and 12, then moved reversely. The lens 16 is moved only in the focusing direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a drive device for moving an optical system, and more particularly to a drive device that can move an optical system two-dimensionally. Such a drive device can be effectively applied to an optical head used, for example, in an optical information recording/reproducing device to optically record information on a recording medium or optically read recorded information from a recording medium. Ru.

[Conventional technology]

In various optical instruments, the entire optical system or a part of the optical system is moved as necessary, and by such movement, the optical path can be changed and a desired imaging relationship can be obtained.

The movement of the optical system is achieved by focusing, which is realized as movement along the optical axis when the object moves in the direction of the optical axis, and tracking, which is realized when the object moves in the direction perpendicular to the optical axis. In some cases, this is realized as movement in a direction perpendicular to the optical axis.

A specific example of such optical system movement is an optical head of an optical information recording/reproducing device.

In an optical information recording/reproducing device, a laser beam emitted from a light source is focused by an optical system and irradiated onto a recording medium such as a disk, and at this time, by applying optical modulation to the beam, the laser beam is Information is recorded. In the case of a disk-shaped recording medium, this information recording is performed by forming minute pattern rows (information tracks) in a concentric or spiral shape while rotating the recording medium. As the micro-turn, unevenness, presence or absence of holes, change in light reflectance, direction of magnetization, etc. are used depending on the type of recording medium used.

When reproducing information recorded on a recording medium, a light beam of a certain intensity is irradiated onto the recording/arm turn of the recording medium, and the light beam modulated by the recording pattern is guided to a light receiving element by an optical system and is subjected to photoelectric conversion. Reproduction of small recorded information is performed.

An optical head is used as a device that includes an objective optical system for recording or reproducing optical information as described above.

By the way, in optical information recording and reproduction, since the recording pattern is minute, it is necessary to irradiate the recording medium with light beams in such a way as to obtain a sufficient focusing state (1) and during reproduction. In this case, it is necessary for the optical beam to follow the information track sufficiently. Therefore, in the optical head, there are 7 orcasing states on the recording medium, and
When the optical system of the optical head or a part of the optical system of the optical head is moved to maintain the proper focusing state and the tracking and king states, control is performed. It is.

For such focusing control, center and king control, conventional optical systems are provided with a focusing control drive means and a center and king control drive means, respectively, independently. Each drive means has a coil fixed to the objective lens and a magnet for generating a magnetic field at the position of the coil. Focusing control and tracking/king control are performed by controlling the amount of current applied to the coil. It is being done.

[Problem that the invention seeks to solve]

Therefore, in conventional optical systems such as those described above, access to the information track requires moving the entire device, including the relatively heavy driving means including the coil and magnet, using other driving means. It is being done. For this reason,
There is a problem in that the weight of the movable parts during access is large, making high-speed access difficult. Further, since the conventional optical head as described above requires many driving means, there is a problem that the number of parts is large, resulting in a large size and high cost.

As mentioned above, the problem that it is difficult to move an optical system two-dimensionally at high speed over a relatively long distance range and that it is difficult to make it compact is not limited to driving the optical system in the direction of light. It is present in all devices for driving the two-dimensional movement of a system.

[Means for solving problems]

According to the present invention, the above-mentioned problems can be solved and the optical system can be moved two-dimensionally over a desired distance at high speed with a relatively simple configuration. They are arranged so as to be able to move independently (by a driving source along the tying direction), and one end of a connecting member extending diagonally to the tying direction is connected to each movable element. An optical system drive characterized in that an υ optical system is supported by the other end of each connecting member, and each of the connecting members, the movable element, and the optical system substantially constitute a parallelogram link. Equipment is provided.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of an optical system driving device according to the present invention, and FIG. 2 is a cross-sectional view taken along line 1--2. This embodiment is applied to driving an objective lens of an optical head.

In FIGS. 1 and 2, 2 and 4 represent a 1° pair of movers. In this embodiment, two pairs of movers 2° and 4 are used. Each pair of movers 2 and 4 is a hollow cylindrical body having an axis of symmetry in the direction connecting them (namely, the xi-x direction). Each mover 2.4 in each pair is XI-X! Two guide members 6 extending in a straight line in the Y direction and arranged in parallel penetrate through each of the guide members 6 . The cough guide member 6 is the mover 2
, 4 has an outer shape corresponding to the hollow cylindrical shape of
It can move along the -Xs direction.

However, one movable element 2 of each pair is connected to each other by a connecting member 8, and the other movable elements 4 are connected to each other by a connecting member 9. Therefore, one movable body is composed of the two movable elements 2 and the connecting member 8, and similarly, the two movable elements 4 and the connecting member 8 constitute one movable body.
and the connecting member 9 constitute another movable body.

Connecting members 8 and 9 are connected to one end of connecting members 10 and 12, respectively. The connecting member 10 consists of two rigid plate-like bodies 10a and 1Ob, and similarly the connecting member 12 consists of two rigid plate-like bodies 12a and 12b.

These connecting members 10°12 are arranged obliquely to the xl-x direction, and these connecting members 10.
An optical system support member 14 is fixed to the end opposite to the connecting end of the connecting member 12. An objective lens 16, which is an optical system, is fixedly supported by the support member 14. Y is the optical axis of the objective lens 16 and is perpendicular to the xi-x direction.

As shown in FIG. 2, each plate-shaped body 10 a p 10
b.

Both ends of 12m and 12b are formed into a claw shape that is substantially perpendicular to the length direction, and the claw-like ends are inserted into the V-shaped grooves formed in the connecting members 8 and 9 and the optical system support member 14. is engaged with. The claw-like end and the groove are the second
It exists over an appropriate width in the direction perpendicular to the plane of the drawing. Further, the shape of the claw-like end portion is a sharp, sharp angle, while the shape of the V-shaped groove is formed at a larger angle than the angle of the claw-like end portion.

Note that the plate-like bodies 10m and 10b are elastic bodies (for example, rubber).
11. The elastic body 11 has a belt-like and annular shape, and a part of its outer peripheral surface is formed by plate-like bodies 10m, 10
It is attached to one side of b. Then, the elastic body 11
As a result, the plate-shaped bodies 10m and 10b are subjected to forces that attract each other.

Therefore, the claw-like ends of the plate-shaped bodies 10&, lOb are held and held in the V-shaped groove of the connecting member 8 and the V-shaped groove of the optical system support member 14 with a predetermined force. Further, the length between the two claw-like ends of the plate-like body 10& and the length between the two claw-like ends of the plate-like body 10b are the same υ, and the length between the two grooves of the connecting member 8 is the same. The plate-shaped bodies 10m and 10 of the optical system support member 14
The length between the two grooves that engage b is the same. In this way, the plate-shaped bodies 10m and 10b, the connecting member 8, and the optical system support member 14 constitute a parallelogram link, and the engaging portions of the four claws and grooves are the rotation axes.Similarly, The plate-shaped bodies 12m and 12b are connected by an elastic body 13, and the plate-shaped bodies 12m and 12b, the connecting member 9, and the optical system support member 14 constitute a parallelogram link.

A magnet 18 for generating a magnetic field is arranged near the movers 2 and 4, and 20 is a yoke. These generate a magnetic field as shown by the dotted line in FIG.

On the other hand, coils 22.
The coils 22 and 24 are each independently connected to an external power source (not shown).

Reference numeral 26 denotes an optical disk, which is an optical information recording medium, which is driven and rotated by an appropriate means in a plane perpendicular to the Y direction, so that at a position P where it intersects the optical axis Y, the information track is aligned in the Xl-Xs direction. It rotates so that it runs in a vertical direction. The light source is located below in Figure 2 and the optical axis Y
A parallel beam of light is irradiated upward along the path, and is condensed by the objective lens 16 to form a minute spot at position P.

3 and 4 are rounded cross-sectional views illustrating the operation of the optical system driving device of this embodiment.

In FIG. 3, each coil 22.degree.
．． 24 experience forces in the same direction in the X, -X, directions as a result of interaction with the magnetic field generated by magnet 18. In this way, the movers 2 and 4 are guided by the guide member 6 and moved in the same direction. In addition, each fill 2
By appropriately setting the characteristics of 2.24, it is possible to make the movement amounts of the four movable elements 2 and 4 the same when the current is applied for the same time, and in this case, the objective lens 16 is moved in the tracking direction (i.e., XI -X direction) and does not move in the focusing direction.

In FIG. 4, each coil 22.
4 receives an opposite force in the Xl-X type direction due to the magnetic field of the magnet 18. Thus, the movers 2 and 4 are connected to the connecting member 1.
It is guided by the guide member 6 and moved in the opposite direction to a position where it meets the elastic force generated by the elastic bodies 11.about.13 having a diameter of 0.12. In this case as well, there are four movers 2,
4 can be made the same amount of movement, thus the objective lens 16 moves only in the scanning direction and does not move in the tracking direction.

Thus, according to the device of this embodiment, by appropriately setting the magnitude of the DC voltage applied to the coils 22, 24 wound around each movable element 2.4 and the direction of application of the voltage with respect to the coil winding direction, the objective The lens e16 can be moved two-dimensionally in the direction of its optical axis and in the direction perpendicular thereto, thereby making it possible to simultaneously perform tracking control and focusing control of the optical information recording/reproducing apparatus.

Further, according to the apparatus of this embodiment, the objective lens 16 can be moved along the Xt-Xs direction and the Y direction over a short stroke, and random access to the information track is possible.

According to the device of this embodiment, since the movable element is moved while being guided by the guide member, the movement of the optical system can be accurately controlled without the movable element moving in a direction perpendicular to the direction of the guide member. I can do it. 'Furthermore, according to the device of this embodiment, the magnetic circuit for drive control for the tiger, king, and focusing can be shared.

Furthermore, according to the apparatus of this embodiment, since the elastic bodies 11 and 13 act as dampers, it is possible to prevent resonance from occurring during movement of the objective lens I6.

FIG. 5 is a partial sectional view showing a second embodiment of the device of the present invention. In this embodiment, the plate-shaped body 1 of the connecting member 12 is
The shape of the claw-like end of 2m and 12b is rounded,
The groove of the connecting member 9 that engages with the end portion and the optical system supporting member 1
The only difference from the first embodiment is that the groove No. 4 is also rounded.

In the above embodiments, the case where the optical system to be driven is an objective lens has been shown, but it goes without saying that the optical system driven by the driving device of the present invention is not limited to an objective lens; Any component of the optical system that constitutes at least a part of the optical system may be used, and it may be a concave lens other than a convex lens, a reflecting mirror, a prism, or the like.

Further, although the above embodiments are applied to driving the objective lens of an optical head, the driving device of the present invention can be applied to driving the optical system of all other optical devices.

Further, in the above embodiment, the optical system is arranged in the direction (i.e., X, - Although a case is shown in which the optical axis is in a direction perpendicular to the focusing direction (i.e., the Y direction), thereby moving the optical system in the focusing direction and one direction perpendicular thereto, the present invention is not limited to such an optical system driving device;
It also includes things that move dimensionally.

In the above embodiment, the coils 22, 24 and the magnet 18 are used as the driving force for the movers 2 and 4, but the driving force for moving the mover in the drive device of the present invention is the same as that in the above embodiment. There is no limitation, and other suitable driving force generating means such as other electromagnetic means, electrostatic means, piezoelectric means, mechanical means, etc. can be used.

Further, although the above embodiment shows a case where there are two pairs of movers, the apparatus of the present invention may have one pair of movers, or three or more pairs of movers may be arranged. From the above embodiment, when two or more pairs of movers are arranged like a molecule, the six pairs of movers move in parallel, connecting one of the six pairs of movers and connecting the other one to each other. Then, a connecting member is connected to these two connected movable element groups.

〔Effect of the invention〕

According to the apparatus of the present invention as described above, the following effects can be obtained.

(1) There are few moving parts and the optical system can be moved two-dimensionally over a short distance.

(2) Since the weight of the movable part is relatively small, the moving speed can be increased, and especially when a pair of movable elements move in the same direction, a large acceleration can be obtained.

(3) Optical system connected to IJ by rigid connecting member
Since the optical system is supported by forming a link, the resonant frequency for moving the optical system is higher than when supporting using a spring, and the adverse effects of resonance can be reduced.

[Brief explanation of the drawing]

Figure 1 is a plan view of the device of the present invention, and Figure 2 is a plan view of the device of the present invention.
■It is a sectional view. 3 and 4 are partial cross-sectional views of the device of the present invention in an operating state. FIG. 5 is a partial sectional view of the device of the present invention. 2.4: Mover, 6: Guide member, 8, 9: Connection member,
10.12: Connection member, 10m+10tz12m, 12
b: plate-shaped body, 11.13: elastic body, 14: support member, 1
62 objective lens, 18: magnet, 22.24 = coil. Agent Patent Attorney Jo Taira Yamashita Figure 1 Figure 2 Figure 3 Figure 4

Claims (4)

[Claims] (1) At least one pair of movers is arranged so as to be movable independently by a driving source along the direction in which they are connected, and each mover is provided with a movable element extending in a direction diagonal to the direction in which they are connected. One end of the connecting member is connected, and the optical system is supported by the other end of each connecting member, and each of the connecting members, the mover, and the optical system substantially constitute a parallelogram link. An optical system drive device characterized by: (2) The optical system driving device according to claim 1, wherein the optical system has an optical axis in a direction perpendicular to a direction connecting the pair of movers in a plane determined by the direction of the pair of connecting members. (3) the mover is moved along the guide member;
An optical system driving device according to claim 1. (4) The optical system drive device according to claim 1, wherein the connecting member has an elastic member for maintaining the link shape.