* NOTICE *
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`/PO and INPIT are not responsible for any damages caused by the use of this translation.
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`1. This document has been translated by computer. So the translation may not reflect the original precisely.
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`2. *** shows 3 word which cannot be translated.
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`3. In the drawings, any words are not translated.
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`Publication Number
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`JP2003043385A
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`Bibliography
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`(19) [Publication country] JP
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`(12) [Kind of official gazette] A
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`(11) [Publication number] 2003043385
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`(43) [Date of publication of application] 26030213
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`(54) [Title of the invention] DAMPING STRUCTURE FOR GALVANO-MIRROR
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`(51) [international Patent Classification 7th Edition]
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`GO2B 26/08
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`GIIB 7/09
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`[Fa]
`GO2B 26/08
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`GtiB 7/08
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`E
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`E
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`(21) [Application number] 2001232155
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`(22) [Filing date] 20010734
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`(77) [Applicant]
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`[Name] OLYMPUS OPTICAL CO LTD
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`(72) [Inventor]
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`[Full namel IKEGAME TETSUO
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`[Full name] SAKAMOTO TETSUYUK!
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`[Theme code (referencse))
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`2HO44
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`§Di18
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`[F-term (reference) |
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`2HO4t AAT2 ABI4 ACO4 AZO4 AZO5
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`5D118 AAI2 AA23 DCO? EAQ2 EBO2 EDO1 FA27 FBOS
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`Abstract
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`

`

`(57) [Overview]
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`PROBLEM TO BE SOLVED: Ta provide a damping structure for a galvano-mirror which
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`can effectively suppress a vibration in a direction vertical to the reflective surface of a
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`reflector.
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`SOLUTION: The galvano-mirror 100 has a mirror 110 to reflect light, a mirror holder 114
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`to which the mirror 110 is attached, a spring part 7172 which supports the mirror holder
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`ii incinably to a magnet halder 120, and a plate 130 arranged on the back surface of
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`ine magnel noider 120. The plaie 130 nas a body pari 131 allached to the back surface
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`of the magnet holder 120, and a projection part 132 provided in the central part of the
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`nody part 131 and extending ai ihe back surface 110b of the mirror. A damping member
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`{damping member) 133, in contact with the back surface 110b of the mirror, is provided
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`at the tip part of the projection part 132.
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`o lain
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`iPatent Claims]
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`iCiaim 1] The galvano miror has a reflecting mirror which reflects light, a movable part
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`which has at least this reflecting mirror, and a supporting member which supporis the
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`reflecting mirror titably with respect to a fixed part.
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`A damping structure for a galvanomirror, comprising | a movable portion : and a damping
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`member that connecis the movable portion and the fixed portion in a direction
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`substantially perpendicular to a reflecting surface of the reflective mirror.
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`[Claim 2] A sensor for detecting an inclinalion of the reflecting mirror is arranged on a
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`back surface of the reflecting mirror.
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`A light source for irradiating light to the connecting part of the damping member or the
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`periphery of the contact part is arranged on the back of the reflecting mirror.
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`The atienuation structure of a gaivanomirror according to claim 1, wherein the inclination
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`af the reflecting mirror is detected by light passing through the connecting portion of the
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`attenuating member or around the contact portion.
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`{Claim 3] The attenuation structure of a galvanomirror according to claim 1 or 2, wherein
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`ine damping member is disposed so as io be in contact with a vicinity of a ulting center
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`of the movable portion.
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`[Ciaim 4] The galvano mirror has a reflecting mirror which reflects light and a supporting
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`member which supporis the reflecting mirror tiliably.
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`An atienuation structure for a galvanometer mirror, comprising : a body portion disposed
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`on a back surface of a reflector ; a protrusion portion extending from a front surface of
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`ine body portion to a rear surface of ihe reflector ; and an attenuation member provided
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`

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`at a tip end of the protrusion partion and connected to or in contact with a back surface
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`of the reflector.
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`Description
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`iDetailed description of the invention]
`
`(O00 4}
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`[Technical field of invention] The present invention relates to a galvano mirror having a
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`reflecting mirror which reflects light and a supporting member which supports the
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`reflecting mirror titably.
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`{9002]
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`[Prior ar] The galvano mirror generally includes an information recording and
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`reproducing device for recording and / or reproducing information on an optical recording
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`medium such as a magneto-optical disk drive, a wrile-once disk drive, a phase-change
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`disk drive, a CD-ROM, a DVD, an optical card, or ihe like, and an optical device such as
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`an optical scanner, an aptical deflector for optical communication, or the like.
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`It is used
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`as @ part of an optical element support device which tits a light flux in a predetermined
`direction.
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`(OO03]For example, Japanese Unexamined Patent Publication No. 7 (1999) - 72409
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`discloses a small optical elament support device (hereinafter, referred to as a prior art 1)
`
`of a* as shown in FIG. 11,12. In this optical element supporting device, a vibrator 30 is
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`atlached to a glass substrate 34 farming an electrode via a spacer 35. The vibrator 30
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`comprises a movable plate 31 for arranging a reflecting mirror (mirror) integrally formed
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`by etching from silicon having a thickness of 0.3 0, and a frame 33 integrally attached to
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`the movable plate 21 vie an S-shaped span bound 32, and the thickness of the movable
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`plate 31 and the span bound 32 is 20 (Gm). Ai the vibrator 30, it is the movable plaie 37.
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`When a volage is applied between the electrade farmed on the glass substrate 34 and
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`the electrode, an electrostatic force acts between the electrodes, and the movable plate
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`31 is attracted to the electrade around the span bound 32 as an axis.
`
`(O004]in addition, Japanese Patent Laid-Open No. 7 (1995) - 72409 also discloses a
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`small optical element support device (hereinafter, referred to as a conventional art 2) of
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`a small * as shown in FIG. 13. In this optical element supporting device, a mirror which
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`is a reflecting mirror consists of a mirror outer peripneral part 42 whichis joined to a gap
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`forming part 43 formed on a glass substrate 44, and a mirror part 40 which is not in
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`contact with a gap forming part 43 supported via a beam 41 extended fram the mirrar
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`outer peripheral pari 42, and this mirror part 40 also functions as a movable plate.
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`

`

`(O005}
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`[Prabiem to be solved by the invention] However, each of the above-mentioned
`
`conventional techniques has suffered from a problem of *, as described below.
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`[(OO0O06]First, in the prior art 1, as shown in FIG. 11,12, since the span bound 32 is provided
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`on the side surface of the movable plate 31 serving as the * and the reflective surface,
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`the rigidity in the direction (perpendicular direction) perpendicular to the surface of the
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`movable plate 31
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`(perpendicular direction)
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`is
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`low and is easily vibrated in the
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`perpendicular direction. For this reason, inere has been a disadvantage in that the light
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`reflected by the surface of the movable plate 31 moves in parallel with respect to the
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`target position.
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`fO007]Nexi,
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`in the prior art 2, when vibration is applied in a direction (perpendicular
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`direction) perpendicular to the reflecting surface of the mirror portion 40, the back surface
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`of the mirror partion 40 collides with the gap farming portion 43, so that the rotation of
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`ine mirror portion 40 is not stabilized.
`
`in addition, since there is no restriction in the
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`direction in which the mirror portion 40 is separated from the gap forming portion 43, itis
`
`not possible to restrict ihe vibration in the direction in which the mirror portion 40 is
`
`separated from the gap forming portion 43. Further, since the beam 41 is positioned on
`
`the side surface of the mirror portion 40 and is bent in the perpendicular direction of the
`
`mirror portion 40, the beam is not very large in rigidity and easily vibrates. Therefore, in
`
`the prior art 2, there is a problem that the light reflected from the surface of the mirror
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`partion 40 causes a displacement of the target pasition.
`
`fO008]lt is an object of the present invention to provide an attenuation structure of a
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`galvano mirror capable of effectively suppressing vibration in a direction perpendicular
`
`io a reflecting surface of a reflecting mirror.
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`jooog]
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`[Means for solving the problem] For this reason, in the attenuation structure according
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`to the 1 aspect of the present invention, the attenuation structure of the galvano mirror
`
`includes a reflection mirror which reflects light, a movable portion which has at least this
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`reflection mirror, and a support member which supports the reflection mirror so as to be
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`ullable relative to the fixed portion. ii has a damping member which connects or coniacis
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`the reflective surface of the aforementioned reflecior perpendicularly substantially in the
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`aforementioned flexible region and the aforementioned holding part.
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`foO1O}According to a 2 aspect of the present invention, in the attenuation structure of a
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`galvanomirror, a sensor for detecting an inclination of the reflecting mirror is disposed on
`
`@ back surface of the reflecting mirror in the 7 aspect. A light source for illuminating light
`
`

`

`is provided on a rear surface of the reflecting mirror so as to irradiate the connecting
`
`portion or the vicinity of the contacting portion of the attenuating member, and the
`
`inclination of the reflecting mirror is detected by the light passing through the connecting
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`partion of the attenuating member or the periphery of the contacting portion.
`
`(001 1JAccording io a 3 aspect of ihe present invention, in the attenuation structure of a
`
`galvanomirror according to the 1 aspect or the 2 aspect, the damping member is
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`disposed so as fo be in contact with the vicinity of a center of inclination of the movable
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`portion.
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`(o012}According to a 4 aspect of ihe present invention, there is provided a gaivano mirror
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`including a reflecting mirror for reflecting light and a supporting member for supparting
`
`the reflecting mirror liably.
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`Ii has the body part placed at the back face of the
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`aforementioned reflector, a protruding part which extends at the back face of the
`
`aforementioned reflector from the front face of the body parl, and a damping member
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`which is provided at ine tip of ine aforementioned protruding par, and connects or
`contacts the back face of the aforementioned reflector.
`
`{0013}
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`[Embodiment of invention] Hereinafter, an embodiment of the invention is described in
`
`detail based on an accompanying drawing.
`
`(OO14)FIG. 1
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`is a system diagram schematicaily showing an operation of an optical path
`
`switching device 10 including a galvanomirror 100 according to a 1 embodiment of the
`
`present invention. FIG. 2 is a perspective view showing a galvanomirror 100 according
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`io a | embodiment of the present
`
`invention, FIG. 3 is an exploded view of the
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`galvanomirror 100, and FIG. 4 is a front view of the galvanomirror 100 ; FIG. 5 is an
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`internal view showing the mirror of the galvanomirror 100 from the inside, FIG. 6 is a
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`ansverse sectional view showing the periohery of the holder of ithe galvanomirror 100,
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`FIG. 7 is a transverse sectional view showing the galvanomirror 100, and FIG. 8 is a
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`iangitudinal sectional view showing the galvanomirror 100.
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`fOO15]As shown in FIG. 1, the optical path switching device 10 includes 1 optical fibers
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`20 to which light which is a transmission signal for* and optical cammiunication is emitted,
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`@ galvano mirror 100 which reflecis the light emitted from ihe optical fiber 20, and a
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`plurality of optical fibers 21 to 29 to which the reflected light is incident. An optical fiber
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`2U has a iens 20 a arranged so that an optical axis coincides with an optical axis, and
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`similarly, optical fibers 21 to 29 are arranged in a total of 9 rows of 3 stages on the same
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`plane and have lenses 21 ato 29 @ arranged so that the optical axes thereof coincide
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`wih each other at the tip of the 3 columns.
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`(OO16]A mirror 110 which is a reflecting mirror constituting a galvanomirror 100 is
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`

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`supported by a spring 112 (see FIG. 3) which is @ support member to be described later
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`freely rotatably around 2 rotation axes Ox and Oy which are orthogonal fo each other.
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`By applying a driving signal (current) to the exciting coils C 1 and C 2 to rotate the mirror
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`110 around the rotation axes Ox and Oy, it is possible to freely set the inclination of the
`mirror 110.
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`(0017}]For this reason, the optical path switching device 10 converts light emitted from
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`ine optical fiber 20 into parallel lighi by the lens 20 a, and projects the emitted light L 1
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`onto the front surface (reflecting surface} 110 f of the mirror 110, and reflects light L 2
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`fram the reflecting surface 110 f. By rotating the mirror 110 around the rotation axes Ox
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`and Oy by the drive signal, 1 of the 9 lenses 21 ato 29 a are selectively incident on ane
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`of the 9 aptical fibers 21 to 29.
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`O078)Thus, the optical path switching device 10 can select and outpul the light output
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`from the 1 optical fibers 20 io 1 of ine Q optical fibers 21 to 29. Note thal the incident light
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`Li and the reflected light L 2 are main light beams deflected by the mirror 110 of the
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`galvanomirror 100.
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`(O01 9}Specifically, the mirror 110 is titted around the rotation axis Ox, the reflected light
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`L 2 at the mirrar 110 is deflected in the X direction shown in FiG. 1, and the reflection
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`light L 2 at ihe mirror 110 is deflected in the Y direction shown in FIG.
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`1 by tilting the
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`mirror 110 around the rotation axis Oy. Thus, for example, the galvanomirror 100 can
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`change the direction of the reflected light L 2 from the lens 21 a to the lens 29 a, and
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`cause the reflecied light L 2 to enter the optical fiber 29 fram ihe optical floer 21. Note
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`that, the mirror 140 maytilt the reflected light L 2 by tilting only either around the rotation
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`axis Ox or around the rotation axis Gy.
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`o020)]Here, a gaivanomirror 100 according to a 1 embodiment of the present invention
`wil be described,
`
`(OO21]As shown in FIG. 2, ihe galvanomirror 100 is arranged at a central portion of the
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`magnetic holder 120, in which a * and a mirror 110 are attached to the front opening of
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`the housing 100 a, and a mirror 110 is arranged in parallel with the horizontal direction
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`A, TO provide a support driving mechanism which is rotatably supported around a rotation
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`axis Ox parallel to a vertical direction Y orthogonal to a horizontal direction X, and to
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`detect a rotational displacement around 2 rotation axes Ox and Oy of a mirror 110. A
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`position detection device is disposed in the housing 110 a on the backside of the mirror
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`100 (utilizing light for 2 dimensional or 2 directions).
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`o0221As shown in FiG. 2, the mirror 110 has a *, square (or rectangular) plate shape,
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`and a reflective surface 110 f on the front side is provided with a coating film so as to
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`

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`increase the reflectance with respect to the wavelength 1.3(um)-1.7(um of the main light
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`used for optical communication, for example. A coating film is provided an a back surface
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`110 > of the mirror 116 (see FIG. 3) so as to increase the reflectance of a laser 140 (see
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`FG. 3) for generating light for a sensor, for example, with respect to a wavelength 7380
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`(nm). Further, ihe mirror 110 is housed in a mounting concave portion 111 (see FIG. 3)
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`at the center of the mirror holder 111 in the form of a square frame, and the periphery
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`thereof is fixed in a state of being positioned.
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`(O023]The mirror holder 111 is Fig.6 ** specifically.
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`This device comprises 4 first part d74 a formed inte a rectangular frame shape on the
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`ouiside and a 2 part 111 b formed into a substantially square frame shape on the inside
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`of the part 111 a, and a mirror 110 is stored and fixed in a mounting recessed part 111
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`n formed in the front of the pari 111b. *. A part 111 ais formed in a siepped shape at a
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`substantially central position in the front-rear direction outside of ine part 1771 6b, and a
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`coil holder function for fixedly holding the 1 coil C 2 and the 2 cail C 1 by the step part of
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`the part 111 @ and the outer peripheral surface of the pari 174 b adiacent to the front and
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`rear of the part is provided.
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`(OO24}in addition, as shown in FIG. 3 4 springs 112 (412a,1120,112c) having a * and a
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`substantially arc shape are arranged at an outer peripheral position of the part 111 a,
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`and both ends of the spring 112 are separately shown in FIG. 5 by disassembling the
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`spring 112 and the magnet holder 120, bul are inserl-molded in the magnet holder 120.
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`(O025]|Specifically, as shown in FIG. 5, when a part 111 a of a“, a mirror holder 111 and
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`a magnet holder 120 are molded of plastics, a 20 (u m) thick foil of beryllium copper is
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`siched, and an inner part of the 4 springs 112 of which gold is plated wih gald is
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`subjected to an eiching process to obtain a part 111 a of a mirror holder 111. The outer
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`part is first insert molded into the magnet holder 120, and both ends thereof are held.
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`(O026]Next, a mirror 110 fixed to the mirror holder 114 and a 2 coil C 1 mounted on an
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`outer peripheral surface of the mirror holder and a 1 coil © 1 constitute a movable par
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`by insert-molding the 2 coil C 2 and the 111 coil C on both front and rear sides of the
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`spring 112 at the time of molding the part 1116.42.
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`[O027]|More specifically, as shown in FIG. 5, each of the 4 springs 112 has one end fixed
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`at each of the center of the upper surface and the center of the lower surface close to
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`the rotation axis Ox of the mirror holder 117, and the vicinity of the fixed end has a 1
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`deformation portion 112 a deformed so as to be parallel to the rotation axis Ox 2. In the
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`vicinity of the 1 deformation portion 112 a, a soldering partion h connected to the 1
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`deformation portion 112 4 inside the mirror holder 114 is arranged, and both terminals of
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`

`

`the PT coiwC 7 and the 4 coil C 2 are fixed to the soldering portions h at a total of 2 portions
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`with a conductive adhesive.
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`(O028]F urther, the other enc of the spring 112 is fixed at 2 positions on the left and right
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`side walls clase to the rotation axis Oy of the magnet holder 120, and the vicinity of the
`
`fixed end at ine other end has a 2 deformation portion 112 6 deformed so as to be parallel
`
`to the rotation axis Oy. Note that an end portion of the 2 deforming portion 112 b
`
`penetrates through a rectangular projecting portion 121 projecting from the left and right
`
`side surfaces of the magnet holder 120 and is inserted inio the magnet holder 120, but
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`the insert portion passes through the magnet holder 120 and reaches the 4 terminals t
`
`protruding fram ihe outer surface of the magnet holder 720.
`
`(OO29)}Further, the spring 112 has a connecting portion 112 c which connects the 1
`
`deforming portion 112 @ and the 2 deforming portion 112 6, and the connecting portion
`
`112 ¢ is arranged as a * surrounding the 4 corners of the mirror holder 117. Aspring 112
`
`having 4 deformation portions 112 a, a 2 deformation partion 112 6, and a connecting
`
`partion 112 ¢ serves as a support member in this embodiment.
`
`foO30}Dampers D t and D 1 which are ultraviolet curing silicon gels are provided on the
`
`first deforming portion 112 a, the soldering portion h, and the 2 deforming portion 1412 b
`
`and ihe projecting portion 121, and ihe damping function for the vibration of ihe both
`
`ends of the spring 112 is maintained. 2.
`
`(OOSTIAs shown in FiG. 3, FRG. 4, FIG. 6, and the like, the magnet holder 120 has 2
`
`magneis m 1 magnetized in the horizontal direction fixed to ine rear surface of the yoke
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`122, and the 1 coll C 4
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`is attached to the inside of the magnet m i at the fefi and right
`
`positions facing each other. Thus, a magnetic circuit
`
`in which the magnetic field
`
`generated by ihe magnet m 1 acts on the 1 coil C 1 disposed opposite io the inside
`thereof is constituted.
`
`(O0S2n addition, as shown in FIG. 3, the magnet holder 120 has 2 magneis m 2
`
`magnetized in the vertical direction, each of which fixes the yoke 123 to the back surface,
`
`and the 2 coil C 2 is attached to the inside of the magnet m 2 by an adhesive.
`
`(OO33]Thus, a movabie pari consisting of a mirror 110, a mirror holder 111 and 2 colis C
`
`j and C 2 is supported io be titable relative fo the magnet holder 120 via 4 springs 112
`
`aS @ suppart member. By soldering the flexible cable to the 4 terminals t (see FIG. 5) and
`
`supplying power via the flexible cable, the drive signals can be supplied to the 2 colls C
`
`j and © 2 via the 4 springs 112 and rotated. In other words, the mirror 110 can be titted
`
`by an amount corresponding ia the driving force generated in the 1 coll C 1 and the &
`
`coil C 2 via the mirror holder 117.
`
`

`

`(O034]The mirror holder 111 and the magnet holder 120 are formed of a non-conductive
`
`plastic (e.g., a liquid crystal polymer containing tHanium tftanate whisker). The magnet
`
`holder 120 has a substantially rectangular frame shape and is bonded to a mounting
`
`surface 100 f which is opened at a front surface of a housing 100 a formed by, for
`
`example, zinc die-casting,
`
`fOOS5Hn this embodiment, a* and a plate 130 are fixed to the rear surface of the magnet
`
`holder 120 as shown in FIG. 3. The plate 130 includes a body portion 131 attached to
`
`ine rear Sufface of ihe magnet holder 120, and a central portion of the body portion 7137.
`
`The front end of the projection 132 extends from the front surface of the magnet holder
`
`720 to the rear surface 110 6 of the mirror 110, and the front end of the projection 132
`
`has * and mirror as shown in FIGS. 6 to 8.
`
`A damping member (damping member) 133 is provided in cantact with 110 of the back
`
`surface 116 b.
`
`[OO36}in this embodiment, the projection 132 of the plate 130 is located at a central
`
`partion of the body portion 131, and the periphery of the projection portion 132 is
`
`connected to the outer peripheral portion 130 a of the plate 131 by 4 thin connecting
`
`portions 130 b.
`
`{O037]In addition,
`
`in the present embodiment, when the plate 120 is fixed on the back
`
`surface of the magnet holder 120, a small gap Ac (e.g., 0.2 to 1} is formed between the
`
`pack surface 110 b ofihe mirror 110 and the tip ofthe projection 122. Thus, the damping
`
`member 133 of the present embodiment is integrally molded, for exampie, by filing a
`
`damping material made of a UV curing gel or the like into the gap Ac and then curing if.
`
`OOS8]As described above, ihe mirror 110, the mirror holder 111, and the 1 and 2 coils ©
`
`i and © 2 constiuie movable paris, and as shown in FIG. &, ihe center of gravity G of
`
`the movable part is on the rotation axis Ox and on the rotation axis Oy. In addition, the
`
`principal axis of inerlia of the movable portion coincides with the rotational axis Ox and
`
`the rotational axis Oy. Further, the damping member 133 is disposed at a position very
`
`close to the center of gravity G and the rotational axes Ox, Oy.
`
`(O039]Furiner, the spring 112 is arranged so as to coincide with a plane defined by the
`
`rotation axis Ox and the rotation axis Oy.
`
`In addition, the 2 deformation portion 112 a
`
`shown in FIG. 5 is dispased at @ position substantially coinciding with the rotation axis
`
`Ox, and the 1 deformation portion 112 6b
`
`is disposed at a position substaniially
`
`corresponding to the rotation axis Oy.
`
`OO40}As shown in FIG. 6, a spring 112 is not disposed at a central position of the 1 coil
`
`& 1 and the 2 coil C 2 mounted in front and rear. A spring 112 is arranged at a position
`
`

`

`close to the 1 coll © 1
`
`in which the mirror 110 is arranged, so that the center of gravity
`
`including the mirror 110 can be made coincident with the rolation axes Ox and Oywithout
`a balancer.
`
`[(OO41]F IG. 6 is a cross-sectional view showing a horizontal plane incluciing the rotation
`
`axis Oy. As shown in FIG. 6, a force is generated in the 1 coil C 1 along the vertical
`
`direction of the drawing with respect to the * and the driving point F 1. Therefore, a torque
`
`is generated around a midpoint Fm 1 connecting the 2 drive points F 1 and F 1 on both
`
`sides of the first coil C 1. Then, the torque around the driving point F 1 and ine middie
`
`point Fim 1
`
`is on a horizonial plane including the rotation axis Oy.
`
`[004214 force is generated on a side of the 2 coil C 2 in the front-back direction of FIG.
`
`6, and ine force is generated in the veriical direction on the upper and lower surfaces
`
`perpendicular to the paper surface of FIG. 6 with respect to the driving point F 2 of FIG.
`
`6, Therefore, a torque is generated centering on a midpoint Fm 2 Gin FIG. 6, the 2 drive
`
`points F 2 and F 2 and the middie point Fm 2 coincide with each other that connect the
`
`2 drive points F 2 and F 2 an both sides of the first call C 2. FIG. 8 is a sectional view
`
`showing a vertical plane including the rotation axis Ox, and from FIG. &, itis understood
`
`that the torque around the drive point F 2 and the midpoint Fm 2 is on a vertical plane
`
`including the rotation axis Ox.
`
`[O043}in other words, as shown in FIG. 6, the torque around the midpoint F 1 (m) and
`
`the torque around ihe midpoint Fm 2 are farmed $0 as to be close to the center of gravity
`
`G.
`
`fo044}The housing 100 a is provided with a sensor for detecting an inclination of the
`
`mirror 110 caused by rotation around the rotation axes Ox.
`
`In the housing 100 a, as
`
`shown in FIG. 3,7, a laser (diode) 140 serving as a light source for a “ and a sensor is
`
`fixed to an opening 100 6 at a rear end of the housing 100 a by press-fitting. in addition,
`
`a PBS (polarizing beam splitter) 154 having a 1/4 A plate 151 bonded thereta is disposed
`
`in front of the laser 140, and one sicie surface (adhesive surface) 152 b of ihe PBS 152
`
`is bonded and fixed to the (one) inner wall surface of the housing 100 a.
`
`(O045]Furiher, the housing 100 a adhesively fixes the lens 153 in front of ihe PBS 742.
`
`Then, ihe laser beam from the laser 140 passes through the PBS152, 1/4A plate 157 and
`
`the lens 153. Light that is irradiated on a plate 130 fixed to a magnet holder 120 and can
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`pass around a projection 132 formed on ihe plate 130 is incident on a rear surface 111
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`b of a mirror 110 held by a lens holder 110. Note that an inner wall shape of the back
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`surface side of the lens holder 111 forms a circular opening 1174 6 (see FIG. 4).
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`(O046]Furiher, as shown in FiG, 7, the housing 100 a is opened at a position onpasiie to
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`an inner wall surface to which the side surface 151 b of the PBS 152 is adhered, and a
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`position detection sensor (PSD) 154 which detects the center position of light irradiation
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`of the projected light in 2 directions is adhered and fixed to the opening portion of the
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`housing 1 a, as shown in FIG. *. The PSD 154 is a 2 dimensional position sensor which
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`ouipuis a center position of light projected onto the light receiving portion 154 a in 2
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`directions (* and Y directions) with a voltage.
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`(O047]Next, an operation of the galvanomirror 100 will be described. When a4 current is
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`supplied to the 1 coil C 4 through 2 of ihe 1 springs 112, a rotational torque is generated
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`ground the rotational axis Ox by the magnetic field received from the magnet m 1
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`disposed on the lefi and right sides of ihe magnet M 1, so that the first deformable portion
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`112 a is subjected to the torsional deformation and the movable portionis tilled (rotaied).
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`(oO48}When a current is supplied to the 2 coil C 4 through the 2 other springs 112, a
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`rotation torque is generated around the rotation axis Oy by the magnetic field received
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`from the magnets m 2 disposed on ihe upper and lower sides of the first coil C 2, and
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`mainly the 2 deformation portion 112 b is subjected to the torsional deformation of the
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`rotation shaft Oyto tilt (rotate) the movable portion.
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`fOO49}The laser beam generated by the laser 140 is incident on the PBS 152 by the P
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`polarized light, passes through the polarization plane 152 a almost 100 percent,
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`becomes a circularly polarized light through the 71/4 A plate 151, is incident on ihe lens
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`153, is condensed by the lens 153, and enters the back surface 110 b of the mirror 410.
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`Light reflected by the rear surface 110 bis 1/4 A.
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`After passing through the plaie 151, the S-polarized light is rotated by 90 degrees and is
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`incident on the polarization plane 184 a by the S-palarized light, so that the S-polarized
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`light is reflected by almost 100 percent and eniers the light-receiving surface 154 a of
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`the PSD 154 in a spot-like manner.
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`[OOSOIA * where the mirror 110 tits about the rotation axis Ox and a light on the light
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`receiving surface 154 a movein the X direction of FIG. 3 (lefi and right directions in FIG.
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`7), and since the mirror 110, which tilts the mirror 154 around the rotation shaft Oy, and
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`ine light on the light receiving surface 7 A move in the ¥ direction (vertical direction in
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`FiG.), the inclination of ihe mirror 110 in 2 directions can be detected by the output of
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`the PSD 154. *.
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`(005 1jAccordingly, by supplying a driving signal for bringing the position detection signal
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`fram the PSD 154 to a desired value forthe T colic 1 and the 2 cod C 2, itis possible to
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`control the inclination angle of the mirrar 110 (the reflecting surface 110 6 of the mirran
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`io a desired value iogether with the movable portion.
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`(O052}The damping member 133 is disposed in a direction perpendicular to the reflecting
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`surface 110 fofihe mirror 1710 and in a direction in which the rigidity of the spring 112 Is
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`iow. Thus, the rigidity in the direction perpendicular to the reflecting surface 110 f of ihe
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`mirror 110, which is a direction in which the rigidity of the 4 springs 112 is low, can be
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`increased remarkably because the damping member 133 serves as a supporiing
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`member in this direction. Therefore, the amplitude of vibration of the mirror 110 in a
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`direction perpendicular to the reflecting surface 110 f of the mirror 110 can be reduced,
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`and the reflected light L 2 is not unnecessarily displaced.
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`(O053}The damping member 133 is positioned in a direction perpendicular io the
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`reflecting surface 110 f of the mirror 110 and at the center of the rear surface 110 b, and
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`is further set at a position closer to the center of rotation of the movable portion.
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`Accordingly, it is possible fo effectively suppress vibration of the movable portion when
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`the movable portion including the mirror 1170 receives external vibration in a direction
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`perpendicular to the reflective surface 110 b of the mirror 110. Also, since the damping
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`member 133 is deformed when the movable partion ratates around the rotation axis Ox
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`ar the rotation axis Oy, vibration in this direction can be suppressed,
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`(0054)F urther, the damping member 133 is disposed close to the center of rotation of the
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`movable partion. Therefore, ihe amount of deformation received by the damping member
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`1338 during * when ihe movable portion is inclined does nol become excessive, and the
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`sensitivily of the movement of the movable portion is not significantly reduced. Further,
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`since the damping member 133 is disposed anly at the center partion af the mirror 110,
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`it is possible to detect the inclination of the mirror 110 by the light passing through the
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`periphery thereof.
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`O055hin a galvano mirror 100 which tits a mirror 170 around a 2 axis, a member which
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`supporis 2 kinds of cails C 1 and C 2 which are formed integrally with the mirror 110 and
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`inclined in directions of 2 axes is arranged so as to sandwich a spring 112 including a
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`center of rotation in 2 directions in a direction perpendicular to a reflecting surface 770 f
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`of a mirror 110. Therefore, the center of the driving torque of the coils C 1 and C 2 can
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`be set so as not to deviate significantly fram the supporling member and the center of
`rotation.
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`{OO56}in addition, it is possible to easily align the center of gravity of the movable portion
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`including the 2 types of coils C 1 and C 2 at the centerof rotation.
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`Therefore, in the driving characteristic of the inclination of the mirror 110, generation of
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`resonance can be suppressed, and servo characteristics can be improved.
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`(O057]Furiner, ihe coils C 1, C 2, which are inclined in 2 directions, aré arranged on both
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`sides of the support member and are vertically spaced from the reflection surface 110 f
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`of ine mirror 110. Therefore, the 2 coils C 1 and C 2 and the magneis m 1 and m 2
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`constituting each magnetic circuit can be easily arranged without interference. With this
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`arrangement, even if the 2 coils C 1 and C 2 are vertically spaced from the reflecting
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`surface 110 f of ihe mirror 110, it is possible to reduce the deviation from the supporting
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`point. Therefore, it is possible to easily arrange the 2 magnets m 1 and m 2 for rotation
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`in the 2 direction, to reduce the mutual magnetic interference of the magnets m 1 and m
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`2 for rotation in the 2 directions, and to reduce the disturbance of ihe magnetism acting
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`an the coils C 1 and ¢ 2.
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`(O058lin this embodiment, since the number of springs 112 is 4, a total of 4 power supply
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`lines (drive lines) ofihe coils C 1 and C 2 generating a driving force in