Abstract:
The optical element drive device is provided which includes: (i) a plurality of movable members to which a plurality of optical elements having functions for changing a path of light are attached, respectively; (ii) a plurality of support mechanisms for independently supporting the plurality of movable members in a displacable condition, (iii) a plurality of drive mechanisms for driving the plurality of movable members, and (iv) a fixed member to which the plurality of movable members are mounted. The plurality of drive mechanisms have coils and magnets, and at least one component of the plurality of drive mechanisms is used to drive at least two of the plurality of movable members.

Description:
This application claims benefit of Japanese Application No. 2000-385619 filed on Dec. 19, 2000, the contents of which are incorporated by this reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a drive device for mirrors utilized in an optical system, such as an optical deflector for optical communications, an optical scanner, or a data recording and playback system for recording and/or playing back data relative to an optical recording medium, such as, for example, a magneto-optical disk drive, write-once-read-many (WORM) disk drive, phase-change disk drive, CD-ROM, DVD, or optical card. 
     2. Description of the Related Art 
     In an optical system, such as a data recording and playback system for recording and/or playing back an optical recording medium, such as CD-ROM, DVD, or optical card, a magneto-optical disk drive, WORM disk drive, phase-change disk drive, or an optical system, such as an optical scanner, a drive device for an optical element, such as a mirror, is utilized to skew a beam of light. 
     As an optical element support device, for example, a galvano-mirror  80  like that shown in FIG. 1 is disclosed in Japanese Unexamined Patent Application Publication No. 11-211969. 
     A hole is provided in the central part of a bottom wall portion  82  of a press-formed base member  81 , the bottom surface of this bottom wall portion  82  is spherical, and is used as the mounting surface  83  for mounting and adjusting this galvano-mirror  80 . 
     A spring assembly  84  is housed within this base member  81 . This spring assembly  84  is constituted from a cantilevered fixed member  85 , and a movable member  86 , which is supported in a freely moving condition on the front surface side of this fixed member  85 . This movable member  86  is supported by springs  87 ,  88  in a freely rotating condition around a mirror rotating axis R in parallel to axis Y as shown in FIG.  1 . 
     A mirror  89  is mounted to the front surface of this movable member  86 , a movable coil  90  is mounted so as to enclose the circumference of this mirror  89 , and these movable member  86 , mirror  89  and movable coil  90  constitute a movable portion. 
     Furthermore, the base member  81  of the front surface side of the mirror  89  is notched and open, and an open portion  91  through which light passes is formed. 
     A lead wire  92  is lead through from the upper and lower portions, respectively, of the above-mentioned movable coil  90 . 
     Further, magnets  93  are arranged and affixed in the empty space portions on both sides of the spring assembly  84 . Furthermore, each part in which each magnets  93  is housed forms a flat-shaped flat portion  94 . 
     The above-mentioned springs  87 ,  88  have an S-shaped spring portion  95 , which is shaped like the letter S, a not-shown reinforced conducting portion, which is formed by connecting to this S-shaped spring portion  95 , and a terminal portion. 
     Thus, this galvano-mirror  80  is constituted such that the mirror  89  and movable coil  90  are affixed to the movable member  86 , the opposite ends of the movable member  86  are linked to the fixed member  85  by means of two S-shaped springs  87  and  88 , two magnets  93  are arranged in the base member  81  side facing two sides of the movable coil  90 , the mirror  89  is supported in a rotatable condition around one axis, and the mirror  89  can be driven and rotated by applying current to the movable coil  90 . 
     In a drive device for an optical element such as a mirror, there are cases when it is desirable to line up a plurality of optical element drive devices corresponding to a plurality of optical paths. When a plurality of galvano-mirrors  80 , which are treated as the prior art optical element drive device shown in FIG. 1, are lined up, the pitch cannot be reduced. Another problem is that the number of parts increases. 
     Further, it is difficult to arrange systematically and compactly a plurality of the mirrors in the prior art shown in FIG.  1 . 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a drive device for small optical elements, which is either capable of reducing the pitch of a plurality of optical elements, or has a small number of parts. 
     Another object of the present invention is to provide a drive device for optical elements, which is well-suited to miniaturizing and arranging a plurality of optical elements. 
     The present invention has a plurality of movable members to which a plurality of optical elements, having a function for changing the path of light, are attached, respectively; a plurality of support mechanisms for supporting the above-mentioned plurality of movable members independently in a displacable condition; a plurality of drive mechanisms for driving the above-mentioned plurality of movable members; and a fixed member to which the above-mentioned plurality of movable mechanisms are attached, and is constituted such that the above-mentioned plurality of drive mechanisms have coils and magnets, and by using at least a part of the above-mentioned plurality of drive mechanisms in common for driving at least two of the movable members of the above-mentioned plurality of movable members, it is possible to reduce the number of parts, and to reduce the costs of miniaturization and assembly. 
     Further, by providing the present invention with a plurality of movable members to which a plurality of optical elements, having a function for changing an optical path, are attached, respectively; a plurality of support mechanisms for supporting the above-mentioned plurality of movable members in a rotatable condition; a common fixed member, which provides a plurality of storage portions for respectively storing each of the movable portions respectively supported by the above-mentioned support members; a plurality of drive mechanisms for magnetically and independently driving the above-mentioned plurality of movable portions, a plurality of optical elements can readily be assembled in a state, wherein this plurality of optical elements are arranged at a small pitch by storing the movable portions respectively supported by the support members in the plurality of storage portions formed in the common fixed portion. 
     Further, the present invention has a plurality of movable members respectively comprising optical elements, which have functions for changing an optical path; a plurality of support mechanisms for supporting the plurality of movable members independently in a displacable condition; and a plurality of magnetic drive mechanisms for driving the above-mentioned plurality of movable members, and is constituted such that by forming at least one member from the magnetic members constituting the above-mentioned plurality of movable members, plurality of support members, and plurality of magnetic drive mechanisms, as a common member, it is possible to reduce the number of parts, and to reduce the costs of miniaturization and assembly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagram showing the constitution of a galvano-mirror of the prior art; 
     FIG.  2  through FIG. 5 are related to a first embodiment of the present invention, and FIG. 2 is a schematic block diagram of an optical path switching apparatus comprising a first embodiment; 
     FIG. 3 is a perspective view showing the overall constitution of the galvo unit of the first embodiment; 
     FIG. 4 is a cross-sectional view showing the structure of one galvano-mirror; 
     FIG. 5 is a perspective exploded view of the movable portion of the galvano-mirror of FIG. 4; 
     FIG.  6 A through FIG. 9 are related to a second embodiment of the present invention, and FIG.  6 A and FIG. 6B are diagrams showing the overall constitution of a galvo unit of the second embodiment; 
     FIG. 7 is a perspective view showing a galvano-mirror being stored and affixed in a housing; 
     FIG. 8 is a diagram showing the structure of one galvano-mirror; 
     FIG. 9 is a diagram showing sensors arranged on both sides of a plane comprising incident light and reflected light; 
     FIG.  10  through FIG. 19B are related to a third embodiment of the present invention, and FIG. 10 is a perspective exploded view of the constitution of a galvo unit of the third embodiment; 
     FIG. 11 is a cross-sectional view showing the structure of a galvo unit; 
     FIG. 12 is a perspective view showing the backside of a galvano-mirror; 
     FIG. 13 is a schematic diagram showing an example of a constitution of an optical path switching apparatus constituted by combining the first and second embodiments; 
     FIG. 14 is a block diagram of FIG. 13 as seen from above; 
     FIG. 15 is a schematic perspective view showing a more concrete example of a constitution of an optical path switching apparatus; 
     FIG. 16 is a schematic diagram of FIG. 15 as seen from the side direction; 
     FIG. 17 is a diagram showing an example of a constitution of another optical path switching apparatus; 
     FIG. 18 is a perspective view showing the constitution of FIG. 17; and 
     FIG.  19 A and FIG. 19B are diagrams showing the constitution of a coupling device in FIG.  17 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiments of the present invention will be explained hereinbelow by referring to the figures. 
     (First Embodiment) 
     A first embodiment of the present invention will be explained in detail by referring to FIG.  2  through FIG.  5 . 
     As shown in FIG. 2, an optical path switching apparatus  10  for optical communications comprises a galvo unit  1  of the first embodiment (as an optical element drive device of the present invention). This galvo unit  1  comprises a plurality of galvano-mirrors, for example, four galvano-mirrors  2 . 
     And then a light emitted from one optical fiber  3  is formed into a collimated beam by a lens  4 , and this incident light  5  is projected at a mirror  6 , which constitutes a galvano-mirror  2 , and which changes the path of the light by reflecting it, and this reflected light  7  is selectively irradiated onto three lenses  8 - 1  through  8 - 3 , and is irradiated onto fibers  9 -i opposite each lens  8 -i (i=1-3). 
     By tilting mirror  6  around a rotation axis  11  (causing rotational displacement), light reflected by mirror  6  is deflected in the up-down direction as shown in FIG. 2, selectively irradiated onto three lenses  8 - 1 ,  8 - 2 ,  8 - 3 , and an optical fiber, which outputs light emitted from a fiber  3  at irradiating side, is selected from among three optical fibers  9 - 1 ,  9 - 2 ,  9 - 3 . 
     Each of four sets includes a fiber  3 , lens  4 , galvano-mirror  2 , three lenses  8 - 1 ,  8 - 2 ,  8 - 3 , and three fibers  9 - 1 ,  9 - 2 ,  9 - 3  and four sets are arranged in lines. Four galvano-mirrors  2  are lined up in the direction of the rotation axis  11 . 
     The four galvano-mirrors  2  are mounted in a housing  12  as a fixing member (See FIG. 3) and constitute a galvo unit  1 . As shown in FIG. 3, this galvo unit  1  is constituted such that, for example, a housing  12  is formed in a substantially rectangular parallelepiped-shaped member, which has the horizontal direction as the longitudinal direction, by providing a long concave storage portion in the horizontal direction of the front surface thereof, and the movable portions of four galvano-mirrors  2  are stored in this concave storage portion so as to be aligned at a predetermined pitch such that the rotation axis  11  of each sits on one straight line, and are supported by support members (specifically, springs  16 ), each of which forms the rotation axis  11 . 
     As shown in FIG. 3, FIG.  4  and FIG. 5, each mirror  6  (which has a 1.5-μm thick coating layer with high light reflectance, applied to the outer surface) is inserted in the center portion of the frame of a holder  14 , which constitutes a square frame-like movable portion, and is affixed with adhesive. 
     Further, two coils  15 - 1 ,  15 - 2 , which are wound in a rectangular shape, and which form a magnetic drive mechanism for magnetically driving the respective movable portions, are stored in concave portions disposed on the upper surface and lower surface of the holder  14 , and are affixed with adhesive. Further, springs  16 , which, for example, are etched from beryllium copper foil and have S-shaped curved portions, are mounted in a fixed condition by insert molding to the central portions of both the right and left sides of the holder  14 , and the end portions of the springs  16 , which protrude from both sides of the holder  14 , are wide. 
     The holders  14  and the housing  12  are formed from a non-conductive plastic, such as, for example, a polycarbonate containing glass fibers and titanic acid whiskers, or a liquid crystal polymer. The eight springs  16  used in one galvo unit  1  are insert molded when the four holders  14  are formed. By making an opening in the portion of the housing  12  on the right side of the holder  14  shown FIG. 4, the eight springs  16  can also be insert molded when forming the four holders  14  and one housing  12 . 
     And, as shown in FIG. 3, each spring  16  becomes a support member for supporting a movable portion in a torsionally deformable condition along the rotation axis  11 . 
     In the housing  12 , two magnets  17  are affixed as magnetic members (more specifically, strong magnetic members) in positions facing the two coils  15 - 1 ,  15 - 2 . As shown in FIG. 4, each magnet  17  is polarized into two poles such that each force acts in the same direction corresponding to the direction of the current of a side of each coil, (the directions of current of two coils  15 - 1 ,  15 - 2  are opposite each other in the horizontal direction) so that mutually opposite direction forces act on the upper and lower coils  15 - 1  and  15 - 2 . 
     Further, each of the two magnets  17  is formed in the longitudinal direction in which the four galvano-mirrors  2  are lined up so as to face all the four coils  15 - 1  (or  15 - 2 ) in the movable portions of the four galvano-mirrors  2 , which are stored and held such that each is aligned inside the concave storage portion formed in the horizontal direction in housing  12 . 
     And, the galvo unit  1  is constituted such that applying current to the two coils  15 - 1  and  15 - 2 , which constitute a pair, enables torque to be generated around the rotation axis  11  relative to the two coils  15 - 1  and  15 - 2  by mutual interaction with the magnetic field from the magnets  17 . By torsionally deforming the springs  16 , which resiliently provide support in the direction of this rotation axis  11 , and by rotationally displacing around the rotation axis  11  a mirror  6 , which is mounted to the holder  14  constituting a movable portion, variable control of the angle of tilt of the mirror  6  is enabled. 
     Furthermore, as described hereinabove, the rotation axis  11  for each galvano-mirror  2  is parallel to the direction of alignment of the four galvano-mirrors  2 . Further, the respective movable portions of the four galvano-mirrors  2  are each independently supported by the springs  16 . 
     As shown in FIG. 4, for example, on the back side of mirror  6 , an LED (light-emitting diode)  19  and a PSD (photodetector)  20  are affixed to the housing  12 . A light from the LED  19  is projected to the back surface of mirror  6 , and the reflected light thereof is incident upon the PSD  20 . The constitution is such that, because the light on the PSD  20  moves in the up-down direction as shown in FIG. 4 according to the angle of tilt when the mirror  6  skews around the rotation axis  11 , it is possible to obtain from this PSD  20  a detection signal corresponding to the angle of tilt. 
     This embodiment is constituted so as to reduce the number of parts, lower costs, and facilitate miniaturization by using such a structure as four galvano-mirrors  2  use the magnets  17  in common. The magnets  17  constitute fixed-side drive members used together with coils  15 - 1 ,  15 - 2 , which are drive members for driving the respective movable portions of the four galvano-mirrors  2 . 
     Further, this embodiment is constituted so as to facilitate miniaturization and make assembly easier than a device that groups individual galvano-mirrors together as in a conventional example, by utilizing a structure, which systematically arranges, stores, and supports with support members the movable portions of a plurality of galvano-mirrors  2  in a concave storage portion formed inside a common housing  12 . 
     Further, this embodiment is constituted so as to enable the minimization of irregularities among products, and to make adjustment work easy by utilizing a structure, which systematically arranges a plurality of galvano-mirrors  2 . 
     The operation of this embodiment will be explained in accordance with a constitution such as this. 
     A galvo unit  1  is arranged as shown in FIG. 2, and incident a light  5  from, for example, left-most optical fiber  3  is irradiated on a mirror  6  of a left-most galvano-mirror  2  of the galvo unit  1 , and a current value applied to coils  15 - 1  and  15 - 2  and the polarization thereof are controlled by a detection signal of a PSD  20  such that the reflected light  7  thereof is irradiated on left-most optical fiber  9 - 1  of the desired three arranged optical fibers  9 - 1 ,  9 - 2 ,  9 - 3 . Control is the same for other galvano-mirrors  2  as well. 
     In this case, since this embodiment systematically arranges and stores the respective movable portions of a plurality of galvano-mirrors  2  inside a common housing  12 , the array pitch can be kept small and miniaturization can be achieved, and, in addition, the arrangement of the incident-side optical fiber  3  and lens  4 , and the arrangement of the optical path switching-side lens  8  and optical fiber  9  can be performed systematically, and the optical path switching apparatus  10  can be made compact. 
     Further, adjustments and so forth can be made simple (When a plurality of individual galvano-mirrors are combined as in conventional examples, and constituted as shown in FIG. 2, the job of setting the individual galvano-mirrors becomes troublesome.). 
     Further, because this embodiment adopts a structure, in which the fixed-side magnetic members constituting drive mechanisms for a plurality of galvano-mirrors  2  are used in common by the plurality of galvano-mirrors  2 , the number of parts can be reduced, assembly can be made easy, and costs can be reduced. 
     This embodiment has the following effects. 
     Since this embodiment adopts a structure, which puts one magnet  17  to combined use in the rotational driving of the movable portions of four galvano-mirrors  2 , the number of magnets  17  can be markedly reduced, and parts and assembly costs can be lowered. 
     Because the movable portions of four galvano-mirrors  2  are respectively supported in a freely movable condition by support members, four mirrors  6  can be skewed independently. 
     Further, because the movable portions of the four galvano-mirrors  2  each have tilt sensors for detecting the tilt of the respective movable portions of the four galvano-mirrors  2 , skewing control is easy, and skewing mirror  6  to make it correspond to three lenses  8 - 1 ,  8 - 2 ,  8 - 3  can be done easily. 
     Further, four holders  14  can be integrally molded together with springs  16 . It is therefore possible to carry out forming, which makes for outstanding volume production capabilities, and enables the respective galvano-mirrors  2  to be arrayed having a small pitch. It is also possible to increase the precision of the mutual positions, skews and pitches of the four galvano-mirrors  2 . 
     (Second Embodiment) 
     Next, a second embodiment of the present invention will be explained by referring to FIG.  6 A through FIG.  9 . Furthermore, portions other than those explained hereinbelow are the same constitution as the first embodiment. 
     As shown in FIG.  6 A and FIG. 6B, a galvo unit  30  of the second embodiment is constituted such that, for example, eight galvano-mirrors  32  are arranged and stored in a common housing  31 . Furthermore, FIG. 6A shows a diagram of the second embodiment as seen from above without skew sensors, and FIG. 6B shows a front view. 
     As shown in FIG. 7, the respective galvano-mirrors  32 , for example, are systematically arrayed in the left-right direction perpendicular to the up-down direction of a rotation axis  33 . In other words, in this embodiment, the galvano-mirrors  32  are arrayed perpendicular to the rotation axis  33 . (By contrast, in the first embodiment, the galvano-mirrors  2  were arrayed parallel to the rotation axis  11 .) 
     The movable portion of each galvano-mirror  32  is formed by affixing a square or rectangular plate-like mirror  35  with adhesive or the like to the center of a mirror holder  34 , and affixing a square frame-like coil  36  such that it makes contact with the circumference thereof. 
     The top and bottom ends of this mirror holder  34  are connected to a galvano-mirror holder  38  via springs  37 , which constitute the movable portion support members, and the mirror holder  34  of the movable portion is supported in a torsionally deformable condition around the rotation axis  33  by the springs  37 . Eight holders  38  are positioned and affixed in respective holder concave storage portions  39  respectively formed at a predetermined pitch in the horizontal direction of housing  31 . 
     In the protruding portions  40  at both sides of the holder concave storage portion  39 , magnet storage portions  40   a  are provided so as to face the coil side in a direction that parallels the rotation axis  33  of the coil  36  of the galvano-mirror  32 , which is stored and affixed in this holder concave storage portion  39 , and a rectangular, plate-shaped magnet  41  is stored and affixed, respectively, therein. 
     That is, the magnet  41  is arranged between two adjacent coils  36 , and the constitution is such that this magnet  41  is used by the coils  36  of the two galvano-mirrors  32  between which the magnet  41  is aligned. 
     Furthermore, a total of nine magnets  41  are utilized with the eight galvano-mirrors  32 , and of these, the two magnets  41  at either end of the housing  31  are used exclusively for the galvano-mirrors  32  at either end, but the seven magnets  41  other than these serve a dual purpose. 
     The orientations of the magnetic poles of the two magnets  41  utilized for one galvano-mirror  32  are such that opposite poles are faced, and, as shown in FIG.  6  and FIG. 7, the orientations of the magnetic poles of the nine magnets  41  are oriented in the same direction. Thus, because the magnetic poles of all the galvano-mirrors  32  are the same even though one magnet  41  is used for two adjoining galvano-mirrors  32 , making the polarization of all the coils  36  the same will enable each galvano-mirror  32  to be driven independently and in the same manner. 
     Further, as shown in FIG.  6 B and in more detail in FIG. 8, sensors for detecting the tilt of a mirror  35  are provided in positions diagonally above and below each mirror  35 , respectively. Furthermore, in FIG. 6B, only two sensors on the right side are shown, but the other sensors are provided in the same manner. 
     As shown in FIG. 8, an LED holder  44  and a PD holder  45  for mounting an LED  42  and a PD  43 , respectively, are affixed to the upper side and lower side of holder  38  in the housing  31 . 
     Furthermore, eight LED  42  are mounted in one LED holder  44 , and eight PD  43  are also mounted in one PD holder  45 . 
     As shown in FIG. 9, a light emitted from the LED  42  is reflected by a reflecting surface  35   a  of the mirror  35  and irradiated onto the PD  43 , the surface of which is partitioned in two. When mirror  35  rotates around the rotation axis  33 , the light incident on the PD  43  moves in the direction of one of the two halves of the partitioned PD  43  (the directions of arrow B). Thus, if the differential output of the two light-receiving surfaces of the partitioned PD  43  is detected, a signal corresponding to the angle of rotation of the mirror  35  can be produced. 
     An incident light  5  for switching an optical path having an optical communications signal, which is emitted from the optical fiber  3  (See FIG. 2) from a direction perpendicular to the rotation axis  33  of the mirror  35 , is irradiated onto the reflecting surface  35   a  of the mirror  35 , and is reflected. The plane comprising this incident light  5  and reflected light  7  is perpendicular to the rotation axis  33 . By contrast, the plane formed by the light from the LED  42 , used as a sensor, via the mirror  35  to the PD  43  is parallel to the rotation axis  33 , and perpendicular to the plane comprising the incident light  5  and the reflected light  7 . Further, the constitution is such that the LED  42  and the PD  43  are arranged so as to sandwich the plane comprising the incident light  5  and the reflected light  7 . 
     Therefore, the LED  42  and the PD  43  can be easily arranged in locations, which do not obstruct the incident light  5  and the reflected light  7 . 
     Furthermore, although the direction in which the galvano-mirrors  32  are arrayed relative to the direction of the rotation axis  33  differs from that of the first embodiment, in this embodiment, too, the lenses  8 - 1  through  8 - 3  and optical fibers  9 - 1  through  9 - 3  of FIG. 2 are arranged in the direction in which the reflected light  7  proceeds within the plane comprising the incident light  5  and the reflected light  7 . 
     As for the effects of this embodiment, the number of galvano-mirrors  32  differs, but by controlling the current value applied to the coil  35  of each galvano-mirror  32 , and the polarization thereof, by the differential output of PD  43  instead of the output signal of PSD  20 , switching can be performed such that a reflected light is irradiated onto a desired optical fiber  9 - 1  through  9 - 3 . 
     This embodiment has the following effects. 
     Dual utilization of the magnets  41  is possible even though the array of the galvano-mirrors  32  (mirrors  35 ) is in a direction perpendicular to the rotation axis  33 . 
     Further, since the constitution is such that the respective galvano-mirrors  32  are stored and affixed in storage portions sytematically formed in the common housing  31 , a galvo unit, which has a plurality of galvano-mirrors  32  in a systematically arrayed condition, can be miniaturized, and, in addition, manufacturing can be done more simply and at lower cost. 
     Further, the LED  42  and the PD  43 , which form an angle sensor of the mirror  35 , can be readily arranged in locations that do not obstruct the incident light  5  and the reflected light  7 . 
     (Third Embodiment) 
     Next, a third embodiment of the present invention will be explained by referring to FIG.  10  through FIG.  19 B. Furthermore, portions other than those explained hereinbelow are the same constitution as the first embodiment. 
     As shown in FIG.  10  and FIG. 11, a galvo unit  61  of the third embodiment is formed by storing and affixing magnets  63  by way of a common yoke  64  in a housing  62  having a bottom, and affixing a mirror plate  66 , which provides a plurality of mirrors  65 , and which constitutes a movable portion, so as to face these magnets  63 . 
     For example, the four mirrors  65  are formed in a mirror plate  66  by etching a thin plate of stainless steel, polysilicon or single-crystal silicon. In this case, each square or rectangular plate-like mirror  65  is etched so that a linear part remains in the center in the left-right direction of the top side and bottom side thereof, and each mirror  65  is resiliently connected to the mirror plate  66  and supported in a rotationally deformable condition by springs  67  formed by these linear parts. In other words, the respective mirrors  65  are supported by treating the central axis that passes through each spring  67  as a rotation axis  68 . 
     Reflectance is enhanced by forming a coating layer of, for example, metal or a multi-layered dielectric film on the surface constituting the reflecting surface of each mirror  65 . An insulating layer is formed on the surface of the backside of the reflecting surface by forming a thin polyimide coating layer, and a coil  69  shown in FIG. 12 is formed by electroforming. 
     As shown in FIG. 10, this mirror plate  66  is provided with positioning holes  70  at each of four corner locations, and, using the respective positioning holes  70  as a reference, is positioned and affixed by inserting thereinto pins  71  provided at the four corners of the upper surface of the housing  62 . 
     Beneath the mirrors  65 , a member, which attaches the yoke  64  to one magnet  63 , which is polarized at  10  poles in the forming direction in which a plurality of mirrors  65  are formed, is stored and affixed inside housing  62 . 
     As shown in FIG. 11, the effective sides  69   a  of the coil  69  are positioned on the boundaries of the magnetic poles of the magnet  63 . Thus, the direction of a magnetic field acting on the effective side  69   a  constitutes a substantially horizontal direction of FIG.  11 . Therefore, when current is applied to the coil  69 , currents of opposite directions flow through the two effective sides  69   a  of each coil  69 , thus generating torque, which cause the mirror  65  to rotate around the rotation axis  68  thereof. 
     The constitution is such that magnetic flux from adjacent magnetic poles acts in common on the two coils  69  used in the two adjacent mirrors  65 . 
     This embodiment has the following effects. 
     Because one magnet  63  is being used to drive a plurality of mirrors  65 , the number of parts is further reduced, and assembly is improved. 
     Since the constitution is such that the magnet  63  is arranged parallel to the reflecting surfaces of the mirrors  65 , and the mirrors  65 , magnet  63  and housing  62  are stacked in one direction, assembly becomes easy. 
     Further, a plurality of mirrors  65 , which constitute movable portions, can be formed simply together with respective support members by etching the common mirror plate  66 , and, in addition, the mirrors  65  can be formed and arrayed at a desired pitch, and a galvo unit, which arrays a plurality of small galvano-mirrors, can be realized at low cost. 
     The above-described embodiments are not limited to the constitutions of the embodiments. For example, the mirrors can be silicon mirrors, plastic molded products, or prisms. 
     Further, as long as there are two or more, there can be as many arranged galvano-mirrors or mirrors as desired. 
     Further, galvano-mirrors or mirrors arranged in a single row were described, but these mirrors can also be arranged two-dimensionally as a plurality of rows. For example, in FIG. 4 of the first embodiment, a 4×2 array of galvano-mirrors can be achieved by arranging yet another magnet (labeled  17   a ) above the top-side magnet  17 , and arranging another row of four galvano-mirrors  2  between the top side magnet  17  and this magnet  17   a . In this case, the top-side magnet  17  is used to drive the eight galvano-mirrors  2 . 
     Further, the present invention is not limited to optical communications, but rather can also be applied to galvano-mirrors for use in optical disk pickup, such as, for example, various tracking via multi-track readouts using multiple beams, and can also be applied to optical scanners in other measuring instruments. 
     FIG. 13 shows an example of a constitution of an optical path switching apparatus for use as an optical switch for optical communications using a galvo unit  1  of the first embodiment and a galvo unit  30  of the second embodiment. 
     In this embodiment, signal light from four optical fibers for inputting is selectively switched to four optical fibers for outputting. 
     This embodiment utilizes two sets of one galvo unit  1  having four galvano-mirrors  2  of the first embodiment, and a device that only uses four galvano-mirrors  32  in the galvo unit  30  of the second embodiment. 
     In this embodiment, an optical path from an optical fiber for inputting to an optical fiber for outputting is arranged parallel to the array direction of the optical fiber for inputting. 
     Light emitted from each optical fiber  3 -i (i=1 to 4) is formed into a collimated light by a lens  4 -i, and this incident light  5 -i is projected onto a mirror  35 -i of a galvano-mirror  32 -i of a galvo unit  30 A having a vertical rotation axis  33 . The reflected light thereof is projected onto mirror  35 - 1  in galvano mirror  32  of a galvo unit  30 B having yet another vertical rotation axis  33 . 
     The reflected light thereof is projected onto mirror  6 -i of galvano-mirror  2  of the galvo unit  1 , which has a horizontal rotation axis  11 , the reflected light thereof is transmitted through a beam splitter  101  constituting a parallel flat plate and irradiated onto a lens  8 -i, and irradiated once more onto an optical fiber  9 -i. 
     Further, a portion of the light incident on the beam splitter  101  (around 1 to 20%) is reflected, and this reflected light is intercepted by a PSD  99 -i arranged therebelow. Each PSD  99 -i detects the position of the light on the light-receiving surface thereof in two directions. Four PSD  99 - 1  through  99 - 4  are arranged corresponding to four incident lights  5 - 1  through  5 - 4 , and these PSD are arranged on a single substrate  100 . 
     The position on PSD  99 -i of a state, wherein the position of light to be irradiated on optical fiber  9 -i is optimum, that is, the light spot irradiated from a lens  8 -i to an optical fiber  9 -i is positioned in the center of optical fiber  9 -i, and the quantity of light transferred from optical fiber  9 -i is the maximum, is stored. 
     The respective light for communications, which passed through the four optical fibers  3 - 1  through  3 - 4  is selectively irradiated onto any of the four optical fibers  9 - 1  through  9 - 4 . 
     The optical fibers  3 - 1  through  3 - 4 , lenses  4 - 1  through  4 — 4 , galvo unit  30 A, galvo unit  30 B, galvo unit  1 , beam splitter  101 , lenses  8 - 1  through  8 - 4 , and optical fibers  9 - 1  through  9 - 4  are arranged on a single plane, and are constituted as substantially letter M shapes as shown in FIG.  15 . Further, these members are arranged inside optical switch box  103 . 
     Therefore, the optical switch box  103  can be made thin. Optical fibers for inputting  3 - 1  through  3 - 4  and optical fibers for outputting  9 - 1  through  9 - 4  are arranged on the same plane of the optical switch box  103 . Thus, the input-output optical fibers can be readily accessed even when the optical switch box  103  is arranged vertically or horizontally. 
     Next, the operation of the optical switch of this embodiment will be explained. 
     At initialization, as shown in FIG. 13, the output of an angle sensor constituting either an LED  42  and PD  43  or an LED  19  and PSD  20 , which each mirror has, is maintained at an output such that the respective angles of the four mirrors  35 - 1  through  35 - 4  of the galvo unit  30 A, the four mirrors  35 - 1  through  35 - 4  of galvo unit  30 B, and the four mirrors  6 - 1  through  6 - 4  of galvo unit  1  become approximately 0 so that light from optical fibers  3 - 1  through  3 - 4  is incident on the optical fibers  9 - 1  through  9 - 4 , respectively. 
     When light for communications is emitted from an optical fiber  3 -i, the respective angles of a mirror  35 -i of the galvo unit  30 A, a mirror  35 -i of the galvo unit  30 B and a mirror  6 -i of the galvo unit  1  are fine tuned so that the position of the light on a PSD  99 -i is ideal. The respective mirrors are driven and controlled so as to maintain the output of the angle sensor arranged at each mirror so that the angles of the respective mirrors are maintained in this state. 
     Next, the operation for switching the light  5 - 1  of optical fiber  3 - 1  to the optical fiber  9 - 4  instead of  9 - 1  will be explained. 
     A mirror  35 - 1  of the galvo unit  30 A uses output from its own angle sensor to tilt so as to achieve a predetermined angle θA. A mirror  35 - 4  of the galvo unit  30 B uses output from its own angle sensor to tilt so as to achieve a predetermined angle θB. As a result of this, light reflected by the mirror  35 - 1  of the galvo unit  30 A is directed toward the mirror  35 - 4  instead of the mirror  35 - 1  of the galvo unit  30 B, and the reflected light thereof is directed toward a mirror  6 - 4  of the galvo unit  1 . 
     The angles of the three mirrors are fine tuned so that the output of a PSD  99 - 4  is ideal, and the respective mirrors are driven and controlled so as to maintain the output of the angle sensor arranged at each mirror so that the angles of the respective mirrors are maintained in this state. 
     As a result of this, the light  5 - 1  outputted from an optical fiber  3 - 1  is switched from optical fibers  9 - 1  to  9 - 4  and outputted. 
     Similarly, it becomes possible for the respective communications lights that have passed through the four optical fibers  3 - 1  through  3 - 4  to be selectively irradiated onto any of the four optical fibers  9 - 1  through  9 - 4 . 
     Furthermore, FIG. 14 shows a case in which the mirror angles are such that a light  5 - 4  of an optical fiber  3 - 4  is switched to an optical fiber  9 - 1  and outputted. 
     Furthermore, in this embodiment, four optical fibers were arranged for input-output, but the number of fibers can be a number other than four as well. For example, there can be one input fiber and two output fibers. In this case, one mirror  35  can be arranged in a galvo unit  30 A, two mirrors  35 - 1 ,  35 - 2  can be arranged in a galvo unit  30 B, and two mirrors  6 - 1 ,  6 - 2  can be arranged in a galvo unit  1 . Further, the number of respective mirrors corresponding to the number of input-output optical fibers can also be arranged according to circumstances. 
     FIG.  15  and FIG. 16 show examples of the constitution of another optical path switching device. FIG. 15 shows a perspective view of a schematic constitution thereof, and FIG. 16 shows the constitution as seen from the side. Furthermore, in FIG. 16, only one of the four optical fibers  3 - 1  through  3 - 4  is shown. In this variation, the optical paths from the optical fibers for inputting to the optical fibers for outputting are arranged perpendicular to the direction in which the optical fibers for inputting are arrayed. In this case, as shown in FIG. 15, there is an effect, which enables the width W of the optical switch box  103  to be made narrower. 
     This embodiment is an optical path switching apparatus shown in FIG.  15  and FIG. 16, and more specific examples of the constitution will be given. 
     The optical path switching apparatus for optical communications is constituted comprising galvo units  30 A and  30 B, which move mirrors  35 , respectively; a galvo unit  1 , which moves a mirror  6 ; and two coupling devices  104 A and  104 B for coupling an optical fiber  3  and a spherical lens  4 , and an optical fiber  9  and a spherical lens  8 . 
     For example, coupling device  104 A has a constitution such as that shown in FIG.  19 A and FIG.  19 B. FIG. 19A shows a perspective view of the coupling device  104 A, and FIG. 19B shows a cross-sectional view. 
     Anisotropic etching of a thin silicon wafer  104  is performed along the ( 111 ) plane on the ( 100 ) plane single-crystal Si substrate forming a plurality (FIG. 19A, for example, illustrates a case in which there are four) of evenly-spaced square pyramid-shaped concave portions  104   a  and V-grooves  104   b  linking to the respective concave portions  104   a . Following etching, cutting is performed using a dicing saw at a position approximately ⅔ from the center of the intersection point of the right inclined face with the left inclined face on the ( 111 ) plane in the figure, which is the end portion  104   c  of the respective square pyramid-shaped concave portions  104   a . In other words, the part indicated by a dotted line in FIG. 19A is cut and the end portion  104   c  side is discarded, preventing a shading for an optical path. 
     Then, a spherical-shaped lens (described as a spherical lens as hereinabove)  4  is used, and this spherical lens  4  is affixed with adhesive to a square pyramidal concave portion  104   a  as shown in FIG.  19 B. Instead of cutting off an end portion  104   c , a V-groove that is deeper than a V-groove  104   b  can be formed, so that an optical path through lens  4  is maintained. 
     An optical fiber  3  has a core diameter of eight microns, and a cladding diameter of 125 microns, and is positioned in the V-groove  104   b . And then, the position of the optical fiber  3  is adjusted in the C direction shown in the figure, the degree of parallelism of the light emitted from the spherical lens  4  is adjusted, the optical fiber  3  is affixed using an adhesive, and a coupling device  104 A is formed. Furthermore, a coupling device  104 B also has the same constitution. 
     Further, as shown in FIG.  17  and FIG. 18, a sensor holder  106 , in which is integrated a half mirror  101 , constituting a multi-layered dielectric film on the surface of a sheet-like parallel flat plate, and a photodetector (PSD)  99  for monitoring the quantity of emitted light of a light beam, is arranged in front of the coupling device  104 B. In addition, two housings  12  shown in FIG. 3 for the first embodiment are used. 
     In the optical path switching device of this embodiment, a plurality of optical fibers  3 , a plurality of optical fibers  9  and a galvo unit  30 B constitute a three-tiered structure, and a galvo unit  30 A and a galvo unit  1  constitute a two-tiered structure. 
     Further, to hold either optical fibers  3  that extend from the coupling device  104 A, or optical fibers  9  that extend from the coupling device  104 B via an optical switch box  103 , a plurality of V-grooves  110  (See FIG. 18) for affixing either the respective optical fibers  3  or optical fibers  9  are formed in a right-side wall portion  103   a , and either optical fibers  3  or  9  are affixed with adhesive in the respective V-grooves  110 . The plurality of optical fibers  3  and  9 , respectively, are protected by a packing  109  comprising a rubber material. 
     As shown in FIG. 17, the top surface and bottom surface of optical switch box  103  are covered, respectively, by covers  105 . 
     Further, as shown in FIG. 18, positioning pins  111  are arranged in a standing condition on unit mounting surfaces inside the optical switch box  103 , respective pin holes are provided in the galvo unit  30 A and the coupling device  104 A, the galvo unit  30 A and the coupling device  104 A are positioned by inserting the positioning pins  111  into the respective pin holes, and are affixed using screws and washers. 
     This device has the following effects. 
     Light irradiated from the tip of optical fiber  3  is formed into a substantially collimated beam by the spherical lens  4 , and reflected by a mirror  35  of the galvo unit  30 A, which is arranged in an opposing position, and the reflected light thereof is reflected by the mirror  35  of the galvo unit  30 B, which is arranged beneath the coupling device  104 A. The reflected light thereof is reflected by a mirror  6  of the galvo unit  1 , which is arranged below the galvo unit  30 A, and irradiated onto a sensor holder  106 , which is arranged below the galvo unit  30 B. 
     The light incident upon this sensor holder  106  is split into two beams by the half mirror  101 , one side is transmitted, converged by a spherical lens  8  and irradiated onto an optical fiber  9 , passes through the inside of this optical fiber  9 , and is sent to the outside. Further, the light reflected by the half mirror  101  is monitored by the PSD  99 . 
     According to this embodiment, there is an effect that makes it possible to constitute a compact optical path switching apparatus. 
     Having described the preferred embodiments of the invention referring to the accompanying drawings, it should be understood that the present invention is not limited to those precise embodiments, and various changes and modifications thereof could be made by one skilled in the art without departing from the spirit or scope of the invention as defined in the appended claims.