JPS6057569B2 - movable mirror device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a movable mirror device for reflecting laser light or the like in a predetermined optical axis direction in an optical information recording/reproducing device such as an optical video disc player.

[Prior Art] A conventional movable mirror device includes a movable permanent magnet provided in a magnetic field formed by a fixed coil portion, and a mirror adhered to the surface of the movable permanent magnet.

However, such a movable mirror device has the disadvantage that it is susceptible to the influence of an external magnetic field generated by an objective lens driving device, etc. that converges a laser beam or the like onto the disk surface. Furthermore, if you simply attach a movable coil to the mirror and try to rotate it, it will be necessary to generate a couple on the mirror, which will complicate the configuration of the magnetic circuit that generates the magnetic flux, and the magnetic flux will not be sufficient for the magnetic gap. I couldn't concentrate.

[Summary of the invention]

The present invention eliminates such drawbacks and provides a more efficient movable mirror device, and more specifically, a single permanent magnet with one end magnetized as a north pole and the other end as a south pole, a pair of yokes abutting one end and the other end of the permanent magnet, respectively;
A flat plate is disposed with a gap between the open ends of each of the pair of yokes, and cooperates with the permanent magnet and the pair of yokes to form a closed magnetic circuit in which a magnetic flux circulates; In the generated magnetic field, a circular coil is arranged to cross the magnetic flux generated in this magnetic field, a circular mirror part is formed with a surface that reflects the light flux, and a fixed fulcrum is formed with a contact surface. , a movable part including the coil and a mirror part, a single base for positioning the permanent magnet, the pair of yokes, the plate, and the rotation fulcrum, and responds to the signal supplied to the coil. It is an object of the present invention to provide a movable mirror device in which the movable portion rotates about the pivot point to deflect the reflected light in a predetermined direction.

〔Example〕

A movable mirror device including an embodiment of the present invention will be explained below.

The movable mirror device basically includes a base 1, a permanent magnet section 2, a yoke 3, a plate 29, and a movable section 4.

At the rear of the base 1, a permanent magnet part 2 is magnetized with one end being magnetized to an N pole and the other end being magnetized to an S pole, and a pair of yokes 3 are fixed in contact with both ends of the permanent magnet part 2 in between. The movable part 4 includes a mirror part 6 bonded to a mirror substrate 22 made of aluminum or the like with double-sided tape or the like, and a mirror part 6 that is wrapped around the mirror substrate 22 in an annular shape.
An annular plate 21 made of aluminum or the like, a coil part 7 wound on the annular plate 21, a core part 12 made of an elastic material such as rubber whose one end is fixed to the back surface of the mirror substrate 22, By means of a locking part 11 made of aluminum or the like fixed to a core part 12 near the free end. configured. Plane 3 of core 12
3 does not cover the entire back surface of the mirror substrate 22,
The back surface 28 of the mirror substrate 22 is formed to be exposed. A conical recess 26 and a ■-shaped long groove 27 are formed on the plane 33.
A trapezoidal protrusion 25 is provided at the center. The rear peripheral part 23 of the mirror substrate 22 and the locking part 1
The inner ends 24 of each mirror substrate 22 are formed at an angle of approximately 45 degrees with respect to the plane 28 of the mirror substrate 22. A plate 29 is bonded to the base 1, and serves as a path for magnetic flux that travels from the permanent magnet portion 2, which is magnetized in the direction of the surface in contact with the yoke 3, through the yoke 3.

That is, the magnetic flux emitted from one end of the permanent magnet section 2 is
The plate 2 reaches the open end of the pair of yokes 3 via one side, and faces the plate 2 from the open end via a magnetic gap.
Return to one end of 9.

Further, the magnetic flux reaches the other end of the plate 29 and returns to the other end of the permanent magnet section 2 via the other open end of the pair of yokes 3 via the magnetic gear j knob again. Therefore, the permanent magnet, the pair of yokes, and the plate constitute a closed magnetic circuit in which the magnetic flux circulates once.

Here, the direction of the magnetic flux crossing the two magnetic gaps is the same, but since the coil portion 7 disposed there is formed in an annular shape, the current with respect to the magnetic flux generated in the two magnetic gaps is The flowing directions are opposite to each other, and a couple of forces that rotate the mirror portion can be obtained.

The hole 9 has a screw 13 that screws together with the base 1;
By adjusting the screw 13, the screw 13 is inserted into the hole 31 and comes into contact with the locking portion 11, thereby locking the movable portion 4 in a predetermined position. The screw 17 is fixed to the base 1, but the screws 14 to 16 are threadedly connected to the base 1, and can be moved back and forth by rotation. screw 1
The tip of the screw 17 fits into the V-shaped long groove 27, and the tip of the screw 17 fits into the conical recess 26, and the pivot point of the movable portion 4 is determined by both. The tips of the screws 15 and 16 come into contact with the back surface 28 of the mirror substrate 22 to limit the rotation limit of the movable part 4. The base 1 has mutually orthogonal surfaces X'', Y'', and Z'' as contact reference surfaces between the permanent magnet part 2 and the yoke 3. A notch 32 is provided at the joint between the x'' plane of the base 1 and the Y'' plane, which is also orthogonal to each other. A predetermined step is formed between the upper part of the base 1 and the uppermost part of the coil part 7. The bottom squares 34 to 37 of the base 1 are each cut at an angle of about 45 degrees.The bottom of the base 1 has screw mounting holes 38 and 39 and half holes. An oval groove 19 is formed.When a current is passed from the terminal 5 to the coil portion 7 via the lead wire 8, the permanent magnet portion 2, the yoke 3 and the plate 2
By the electromagnetic force generated by the magnetic field formed through the screws 14 and 17, the fulcrum is defined by the tips of the screws 14 and 17 and the two receiving parts of the V-shaped long groove 27 and the conical recess 26. The movable part 4 rotates in the direction of the arrow in FIG. 4 about the axis. As a result, the optical axis direction of the beam reflected by the mirror portion can be changed in a predetermined direction. The rotation limit is determined by adjusting the screws 15 and 16 and moving them back and forth to change the position in contact with the plane 28 of the mirror substrate. When current no longer flows through the coil portion 7, the elasticity of the core portion 12 causes the movable portion 4 to return to its original position. In order to mount such a movable mirror device on a predetermined substrate (not shown) of an optical information recording/reproducing device, a boss is formed on the substrate corresponding to the semi-elliptical groove 19 of the movable mirror device. .

The boss has a diameter that is approximately the same as the width of the semi-elliptic groove 19, and the movable mirror device can be slid by fitting the boss into the semi-elliptic groove 19. Furthermore, oval holes are formed on the substrate in correspondence with the screw mounting holes 38 and 39 of the movable mirror device so that the movable mirror device can be slid therein. After the movable mirror device is regulated in the left-right direction by the boss and the screw, it is slid in the front-rear direction and is finally fixed by firmly tightening the screw at a predetermined position. The movable mirror device is regulated at three points, so there is little misalignment, and one of those points is a sliding contact pair between a boss and a semi-elliptical groove instead of a screw, and the remaining two points are fixed with screws, so it can be fixed at the specified position. It is possible to fix it accurately in the position. Since the squares 34 to 37 of the base 1 are cut into approximately 45 squares, it can be mounted in a relatively narrow space without coming into contact with other devices.

Since the pivot points are formed at the tips of the screws 14 and 17, they can be aligned accurately with the receiving grooves 26 and 27.

In addition, since the grooves for receiving the tip numbers of the screws 14 and 17 are a conical recess 26 on one side and a V-shaped long groove 27 on the other, the distance between the screws 14 and 17 is the same as that of the conical recess 26 and the ■-shaped groove. Even if the distance to the long groove 27 does not exactly match, if the length of the V-shaped long groove 27 is appropriately selected, manufacturing dimensional variations can be absorbed. The pivot points are screws 14 and 17 made of metal or the like, and a receiving groove 26 made of rubber or the like.
27, whereas the rotation limit is defined by the contact between the screws 15 and 16 made of metal or the like and the back surface 28 of the mirror board made of metal or the like, so the rotation fulcrum may resonate or rotate. There is no risk that the limits will become unclear. Further, since the trapezoidal protruding portion 25 is formed to protrude from the plane 33 of the core portion 12, the bending point of the core portion 12 can be located at the rear, and the restoring force of the movable portion is increased. Further, since the rear surface peripheral portion 23 of the mirror 1-substrate 22 is formed at an angle of approximately 45 plates with respect to the plane 28, the mirror substrate 22 can be lightened while providing sufficient strength to the peripheral portion. Furthermore, since the inner end 24 of the locking part 11 is also formed to have a diameter of about 45, it is possible to inject rubber or the like into a predetermined mold when joining the mirror substrate 22 and the locking part 11 with the core part 12. The locking portion 11 can be fixed at an accurate position with respect to the mirror substrate 22. [Results] The movable mirror device according to the present invention does not use a permanent magnet in its movable part, so its mass is small, and the distance between the mirror part and the rotational fulcrum can be shortened, so the movable part does not make minute changes. can be followed, and the influence of external magnetic fields can be reduced.

Furthermore, since a permanent magnet, a pair of yokes, and a plate form a closed magnetic circuit in which the magnetic flux circulates, there is less magnetic flux leakage and it is possible to increase the magnetic flux density in the gap formed between the yoke and the plate. As a result, the magnetic circuit and the entire movable mirror can be downsized. Since the base 1 has three mutually perpendicular surfaces x'', Y'' and Z'', the permanent magnet portion 2 and the yoke 3 can be accurately fixed with an adhesive or the like without using a jig.

In addition, when the yoke 3 is formed as shown in FIG. 7, its bent portions 3a to 3d may protrude from the reference plane, but the base has a notch at the joint between the X'' plane and the Y'' plane. 32, and a predetermined step is provided between the Z plane and the plane 30, so that the yoke 3 can be fixed without being affected by these protruding parts. Further, although the coil portion 7 is exposed to the outside, the base 1 has a protruding portion 10.
When the movable part 4 is attached to the base 1, the coil part 7
Since the height is approximately the same as or higher than the top of the base 1, the protrusion 10 and the bottom of the base 1 can be grasped with fingers, and the coil portion 7 may be inadvertently touched with the fingers. There is no risk of contaminating or damaging the coil part by grabbing it.

[Brief explanation of drawings]

Each figure shows a movable mirror device including an embodiment of the present invention, and FIGS. 1 to 6 are a front view, right side view, bottom view, top view, rear view, and front view of the movable mirror device. Each represents a central longitudinal cross-sectional view. FIG. 7 shows a perspective view of the yoke 3, and FIGS. 8 to 11 show a front view, a top view, a right side view, and a rear view, respectively, with the movable part removed. 12 to 15 show a front view, a right side view, a rear view, and a front view center cross-sectional view of the movable portion, respectively. DESCRIPTION OF SYMBOLS 1... Base, 2... Permanent magnet part, 3... Yoke, 4... Movable part, 5... Terminal, 6・・・・・・Mirror part, 7
・・・・・・Coil part.

Claims (1)

[Scope of Claims] 1. A movable mirror device capable of deflecting reflected light in a predetermined direction, comprising a single permanent magnet with one end magnetized as an N pole and the other end as an S pole, and one end of the permanent magnet. and a closed magnetic field, which is disposed with a gap between a pair of yokes abutting the other end and each open end of the integrated yokes, and where the magnetic flux circulates in cooperation with the permanent magnet and the pair of yokes. A flat plate forming the circuit, an annular coil placed in the magnetic field generated in the gap so as to cross the magnetic flux generated by this magnetic field, and a disk-shaped mirror with a surface that reflects light flux. a single base for positioning the permanent magnet, the pair of yokes, the plate, and the rotation fulcrum; A movable mirror device characterized in that the movable portion deflects the reflected light in a predetermined direction by rotating about the pivot point in response to a signal supplied to the coil. 2 The yoke has three orthogonal planes, and the base has three orthogonal planes corresponding to the three planes formed on the yoke.
The movable mirror according to claim 1, wherein the movable mirror has a flat surface, and the relative positional relationship between the yoke and the base is defined by bringing the pair of three flat surfaces into contact with each other. Device. 3. Claims 1 or 2, characterized in that the base has a protrusion that protrudes outward beyond the annular coil when the movable part is attached to the base. The movable mirror device described.