A two-dimensional light deflector includes first and second deflectors that deflects a light beam, and a fixing member directly fixing both the first and second deflectors. The first deflector includes a light radiating portion, supported oscillatably around a first axis, to radiate the light beam toward the first axis along a first plane perpendicular to the first axis. The second deflector includes an oscillatable reflecting face that reflects the light beam. The reflecting face is inclined by 45 degrees to the first axis and a second axis coincident with a principal ray of the light beam from the radiating portion. The reflecting face is oscillatably supported around a third axis passing through an intersection of the first and second axes and perpendicular to both the first and second axes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a two-dimensional light deflector that two-dimensionally deflects a light beam.

2. Description of the Related Art

Two-dimensional light deflectors that two-dimensionally deflect a light beam include a deflector in which two galvano deflectors each having a mirror are orthogonally disposed. In such a two-dimensional light deflector, when the light beam is actually two-dimensionally deflected, the locus of the light beam is distorted on an image plane.

U.S. Pat. No. 4,838,632 discloses a two-dimensional light deflector with such reduced distortion.FIG. 18andFIG. 19show a two-dimensional light deflector disclosed in U.S. Pat. No. 4,838,632.FIG. 18is a side view of the two-dimensional light deflector, andFIG. 19is a front view of the two-dimensional light deflector. As shown inFIG. 18andFIG. 19, a two-dimensional light deflector500includes a first deflector510and a second deflector520. The first deflector510includes a movable plate512having a reflecting face and a bracket514that oscillatably supports the movable plate512around a first axis A1. The second deflector520causes the first deflector510to oscillate around a second axis A2orthogonal to the first axis A1. The first deflector510is fixed to the second deflector520so that the reflecting face of the movable plate512at the time of non-deflection is at an angle of 45 degrees with respect to the second axis A2. A light beam LB1to be deflected falls on the first deflector510parallel to the second axis A2. A light beam LB2reflected by the reflecting face of the movable plate512falls on an image plane534through a lens532.

The two-dimensional light deflector500achieves a reduction in the distortion of the trajectory of the light beam on the image plane while being extremely compact with a simple configuration.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a two-dimensional light deflector that deflects a collimated light beam two-dimensionally. The two-dimensional light deflector includes a first deflector that deflects the collimated light beam in a plane, a second deflector that deflects the collimated light beam in another plane, and a fixing member directly fixing both the first deflector and the second deflector. The first deflector includes a light radiating portion that generates the collimated light beam from light guided by a light guide and radiates it. The light radiating portion is supported oscillatably around a first axis extending outside of the light radiating portion, and radiates the collimated light beam toward the first axis along a first plane perpendicular to the first axis, so that an oscillation of the light radiating portion causes deflection of the collimated light beam along the first plane. The second deflector includes an oscillatable reflecting face that reflects the collimated light beam radiated from the light radiating portion. The reflecting face is inclined by 45 degrees with respect to a plane including the first axis at a time of non-oscillation, and is also inclined by 45 degrees with respect to a plane including a second axis that coincides with a principal ray of the collimated light beam radiated from the light radiating portion at the time of non-oscillation, so that the reflecting face converts deflection of the collimated light beam in the first plane into deflection of the collimated light beam along a second plane perpendicular to the second axis. The reflecting face is also oscillatably supported around a third axis passing through an intersection of the first axis and the second axis, and perpendicular to both the first axis and the second axis, so that an oscillation of the reflecting face around the third axis causes deflection of the collimated light beam in a third plane perpendicular to the third axis.

Advantages of the invention will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment

FIG. 1,FIG. 2, andFIG. 3respectively show a perspective view, a side view, and a top view of a two-dimensional light deflector100according to a first embodiment of the present invention. In the following explanation, a positional relationship, directions, and the like of each element will be explained in accordance with an XYZ-orthogonal coordinate system shown inFIG. 1. In addition, for the sake of convenience, according toFIG. 1, it is assumed that a +Y direction is an upward direction, a −Y direction a downward direction, the +X direction a frontward direction, and a −X direction a rearward direction. Furthermore, it is assumed that a plane parallel to a ZX-plane is a horizontal plane.

The two-dimensional light deflector100is an optical device that deflects a collimated light beam two-dimensionally, and comprises a first deflector110that deflects the collimated light beam in a plane, for example, along a YZ-plane, a second deflector150that deflects the collimated light beam in another plane, for example, along an XY-plane, and a fixing member180directly fixing both the first deflector and the second deflector.

The fixing member180has two convex portions protruding upward from a base182, a first deflector fixing stand184and a second deflector fixing stand186. The first deflector fixing stand184has a first deflector fixing face184ato which the first deflector110is fixed, the first deflector fixing face184abeing parallel to the ZX-plane. On the other hand, the second deflector fixing stand186has a second deflector fixing face186ato which the second deflector150is fixed, the second deflector fixing face186abeing declined 45 degrees around the Z-axis with respect to the ZX-plane. Here, the expression 45 degrees includes a range in which a functional difference does not substantially occur.

The first deflector110comprises a light radiating portion120that generates and radiates a collimated light beam from light guided by an optical fiber130, which is a light guide, and a cantilever112supporting the light radiating portion120oscillatably around the first axis A1extending outside the light radiating portion120. Although not shown, the first deflector110also includes a drive mechanism or a drive for oscillatably driving the cantilever112. For driving the drive, any publicly-known drive such as an electromagnetic drive, an electrostatic drive, a piezoelectric drive, or the like may be adapted.

The cantilever112is fixed to the first deflector fixing face184aof the first deflector fixing stand184of the fixing member180in a cantilever fashion. The first axis A1extends through a fixed end112aof the cantilever112. The cantilever112has an extension114extending parallel to the first axis A1near its free end112b, and the light radiating portion120is provided at a distal end of the extension114. The light radiating portion120radiates a collimated light beam towards the first axis A1along the YZ-plane that is perpendicular to the first axis A1. Accordingly, the oscillation of the light radiating portion120around the first axis A1causes deflection of the collimated light beam along the YZ-plane. Furthermore, the collimated light beam radiated from the light radiating portion120always passes through the first axis A1.

The second deflector150has an oscillatable reflecting face152that reflects the collimated light beam radiated from the light radiating portion120. The reflecting face152is inclined by 45 degrees with respect to the ZX-plane including the first axis A1at the time of non-oscillation. The reflecting face152is also inclined by 45 degrees with respect to the YZ-plane including a second axis A2that coincides with a principal ray of the collimated light beam radiated from the light radiating portion120at the time of non-oscillation. Accordingly, the reflecting face152converts the deflection of the collimated light beam in the YZ-plane into a deflection of the collimated light beam along the XY-plane that is perpendicular to the second axis A2.

Furthermore, the reflecting face152is oscillatably supported around a third axis A3passing through an intersection of the first axis A1and the second axis A2, and perpendicular to both the first axis A1and the second axis A2. Accordingly, the oscillation of the reflecting face152around the third axis A3causes deflection of the collimated light beam along the XY-plane perpendicular to the third axis A3.

Therefore, the combination of the oscillation of the light radiating portion120around the first axis A1and the oscillation of the reflecting face152around the third axis A3deflects the collimated light beam two-dimensionally along the YZ-plane.

The second deflector150is configured by, for example, a MEMS deflector. The second deflector150configured by the MEMS deflector comprises a movable plate154provided with the reflecting face152, a pair of hinges156supporting the movable plate154oscillatably around the third axis A3, and a pair of supports158supporting the hinges156. The supports158are fixed to the second deflector fixing face186aof the second deflector fixing stand186through a spacer160. As a result, the movable plate154is oscillatably supported apart from the second deflector fixing face186a. Although not shown, the second deflector150also comprises a drive mechanism or a drive for oscillatably driving the movable plate154. For driving the drive, any publicly-known drive such as an electromagnetic drive, an electrostatic drive, a piezoelectric drive, or the like may be adapted. Since an actual MEMS deflector is provided with a drive, it is easily expected that the MEMS deflector is more complicated and larger than the illustrated configuration.

The second deflector150configured by the MEMS deflector is used as a high-speed scanning side in a raster scan. In high-speed scanning, adopting resonance driving, which can utilize a gain of a Q value, can further reduce power consumption. In addition, since a main material of the second deflector150is manufactured by MEMS technology, in many cases, a silicon substrate is used as the main material. However, for the hinges156, a silicon compound such as silicon nitride, or an organic material such as polyimide may be adapted as well silicon. In addition, in the drawing, each hinge156has a straight shape, but may also be configured by a bending hinge or the like.

As shown inFIG. 2, the height of the first deflector fixing face184aof the first deflector fixing stand184is designed so as to be exactly the same as an oscillation axis of the reflecting face152of the second deflector150. As shown inFIG. 3, the cantilever112is disposed so that, when the center of the thickness of the cantilever112(in the Z-axis direction) is extended in the direction of the second deflector150, the center line of the thickness of the cantilever112crosses the center of the reflecting face152of the second deflector150. This design has a desirable positional relationship from the viewpoint of reducing the moment of inertia (speeding up) of the movable plate154of the second deflector150.

As shown inFIG. 2, the length (the dimension in the Y-axis direction) of the cantilever112is designed so that the height of the free end112bof the cantilever112is higher than the height of the second deflector fixing face186a. The extension114provided near the free end112bof the cantilever112extends frontward, that is, in the +X direction toward the second deflector150. The light radiating portion120provided at the end of the extension114is located above the reflecting face152of the second deflector150, that is, in the +Y direction.

As shown inFIG. 4, the cantilever112, in particular the extension114, includes a cladding fixing portion116fixing a cladding134of the optical fiber130. The cladding fixing portion116has a cavity116ain which the cladding134of the optical fiber130is fitted and is accommodated. The cavity116aextends parallel to the first axis A1. The cavity116ais configured by, for example, a groove or a through hole. The cladding134of the optical fiber130is fixed to the groove or the through hole by adhesion.

The portion of the optical fiber130inserted into the cavity116aof the cladding fixing portion116is a cladding134from which a jacket138and a coating portion136are stripped off of the optical fiber130. Since the diameter of the coating portion136and the jacket138of the optical fiber130has a large tolerance, if the diameter of the cavity116ais increased in accordance with the diameter of the coating portion136and the jacket138, it would be difficult for the optical fiber130to be fixed while achieving good reproducibility of a light radiating direction from the optical fiber130. On the other hand, since the tolerance of the diameter of the cladding134is smaller than that of the coating portion136and the jacket138, the diameter of the cavity116acan be appropriately designed; high reproducibility of the light radiating direction from the optical fiber130can be obtained.

As shown inFIG. 4andFIG. 5, the light radiating portion120comprises a collimating lens122that shapes the light radiated from the optical fiber130into a collimated light beam. Accordingly, the collimated light beam is radiated from the collimating lens122along the first axis A1. The light radiating portion120further comprises a prism124that deflects the collimated light beam radiated from the collimating lens122along the first axis A1toward the reflecting face along the second axis A2. The prism124is fixed to the extension114through a prism attaching portion124a.

The collimating lens122is fixed directly to the optical fiber130as shown in, for example,FIG. 4. As shown inFIG. 5, it may be configured that the cladding fixing portion116includes an optical fiber positioning part116bthat has a smaller diameter than that of the cavity116aat the front end of the cavity116a, the extension114further includes a propagating portion118with a diameter that would not affect the light radiated from the optical fiber130at the front of the optical fiber positioning part116b, and the collimating lens122is attached to the distal end of the extension114, which is the front end of the propagating portion118. In this case, the optical fiber positioning part116band the propagating portion118are designed so as to have a diameter that would not affect the light radiated from the optical fiber130.

InFIG. 1toFIG. 3, in the two-dimensional light deflector100configured in the manner above, the light radiated from the optical fiber130is converted into a collimated light beam by the collimating lens122while traveling in the +X-axis direction, subsequently reflected by the prism124and deflected in the −Y-axis direction, and then reaches the reflecting face152of the second deflector150.

The cantilever112oscillates around the first axis A1that is parallel to the X-axis and passes through the first deflector fixing face184a. Since the first deflector fixing face184ais at the same height as the oscillation axis of the reflecting face152of the second deflector150, although a traveling direction of the collimated light beam reflected by the prism124changes in response to the oscillation of the cantilever112, the collimated light beam reflected by the prism124always travels toward an intersection of the first axis A1and the third axis A3. Subsequently, the collimated light beam is reflected frontward, that is, in the +X direction by the reflecting face152that is disposed at the intersection of the first axis A1and the third axis A3. The collimated light beam reflected by the reflecting face152is deflected in the second plane by the oscillation of the light radiating portion120, and is deflected in the third plane by the oscillation of the reflecting face152.

Hereinafter, a deflection operation of the collimated light beam in the two-dimensional light deflector100will be explained in detail with reference toFIG. 6toFIG. 8. In the following explanation, a plane perpendicular to the first axis A1is referred to as a first plane P1, a plane perpendicular to the second axis A2is referred to as a second plane P2, and a plane perpendicular to the third axis A3is referred to as a third plane P3.

The light radiating portion120is disposed on the first plane P1in an oscillatable manner around the first axis A1. When oscillating, the light radiating portion120reciprocates in a predetermined angular range on a circumference having a constant radius from the first axis A1. Since the light radiating portion120radiates the collimated light beam toward the first axis A1on the first plane P1, the collimated light beam radiated from the light radiating portion120always reaches an intersection of the first axis A1and the first plane P1. The reflecting face152is disposed on the intersection of the first axis A1and the first plane P1. The reflecting face152is disposed in an oscillatable manner around the third axis A3. The third axis A3passes through the intersection of the first axis A1and the first plane P1and extends perpendicularly to both the first axis A1and the second axis A2. The reflecting face152is inclined by 45 degrees with respect to the first plane P1around the third axis A3at the time of non-oscillation.

The collimated light beam radiated from the light radiating portion120at the time of non-oscillation travels along the second axis A2, falls on the reflecting face152, and is reflected along the first axis A1by the reflecting face152at the time of non-oscillation.

As shown inFIG. 6, when the light radiating portion120is oscillated around the first axis A1, the collimated light beam reflected by the reflecting face152at the time of non-oscillation is deflected in the second plane P2.

Furthermore, as shown inFIG. 7, when the reflecting face152is oscillated around the third axis A3, the collimated light beam radiated from the light radiating portion120at the time of non-oscillation and reflected by the reflecting face152is deflected in the third plane P3.

Accordingly, combining the oscillation of the light radiating portion120around the first axis A1and the oscillation of the reflecting face152around the third axis A3allows the collimated light beam reflected by the reflecting face152to be two-dimensionally scanned, as shown inFIG. 8.

Now, a case in which a raster scan is performed using the two-dimensional light deflector100will be explained. Here, the first deflector110is adapted for a low-speed scan and the second deflector150is adapted for a high-speed scan. The collimated light beam radiated from the light radiating portion120and reflected by the reflecting face152is scanned in a low-speed scan SL direction shown inFIG. 8by the oscillation of the light radiating portion120. The collimated light beam radiated from the light radiating portion120and reflected by the reflecting face152is scanned in a high-speed scan SH direction shown inFIG. 8by the oscillation of the reflecting face152. Combining the oscillation of the light radiating portion120and the oscillation of the reflecting face152allows the collimated light beam to be raster-scanned. In this case, the oscillation frequency is assumed to be, for example, 4 kHz or 8 kHz for the high-speed scan and 15 Hz to 60 Hz for the low-speed scan.

Here, the third axis A3, which is the oscillation axis of the reflecting face152of the second deflector150, is not exactly on the reflecting face152of the second deflector150, but is located at the center of a cross-section of the hinges156, so that there is an offset d between the third axis A3and the reflecting face152, as shown inFIG. 9andFIG. 10. However, since the thickness of the hinges156of the second deflector150manufactured by the MEMS technology is generally small, this offset d can be ignored in reality. That is, in the present specification, the reflecting face's152oscillating around the third axis A3allows the reflecting face152to oscillate around the third axis A3off the reflecting face152within a range that would cause no defects.

Although the two-dimensional light deflector100of the present embodiment is not configured in a manner that a deflector is mounted on another deflector as in the two-dimensional light deflector500of the conventional example disclosed in U.S. Pat. No. 4,838,632, a raster scan can be achieved with a substantially rectangular scanning surface in the same manner as the two-dimensional light deflector500of the conventional example. On the other hand, since the elements mounted on the cantilever112are only the optical fiber130, the collimating lens122, and the prism124, which are compact and lightweight, the moment of inertia of the cantilever112is greatly reduced as compared to the two-dimensional light deflector500of the conventional example. Therefore, even when securing the same responsiveness as the two-dimensional light deflector500of the conventional example, the driving force required thereby is greatly reduced, so that the power consumption required for oscillation is greatly reduced. In addition, as the driving force is reduced, the volume required for driving is also reduced, which enables to achieve significant downsizing from the two-dimensional light deflector500of the conventional example.

Modified Example

FIG. 11shows a modified example of the first embodiment. In the two-dimensional light deflector100shown inFIG. 1, since the cantilever112has the extension114on one side, the extension114may move unexpectedly due to an impact or the like by an external force. A two-dimensional light deflector100A of the present modified example includes, as shown inFIG. 11, a cantilever112A that has an adjusting extension119extending parallel to a first axis A1in a direction opposite to an extension114near its free end. The adjusting extension119has the same mechanical characteristics as the extension114. For example, the adjusting extension119has the same length and the same mass as the extension114. As described above, since the cantilever112A has the adjusting extension119similar to the extension114on the opposite side of the extension114, the balance against vibration etc. is improved, so that the cantilever112A is strong against an external impact.

Second Embodiment

FIG. 12andFIG. 13respectively show a side view and a top view of a two-dimensional light deflector according to a second embodiment of the present invention. InFIG. 12andFIG. 13, members denoted by the same reference numerals as those shown inFIG. 1toFIG. 3are the same members, for which detailed explanations will be omitted. The following explanations will be provided while placing importance on the parts different from those inFIG. 1toFIG. 3. That is, portions not mentioned in the following explanation are the same as those in the first embodiment.

In the first embodiment, the mechanism that oscillates the light radiating portion120is configured using the cantilever; however, in the present embodiment, the mechanism is configured using a movable plate.

A two-dimensional light deflector200comprises a first deflector210that deflects a collimated light beam in a plane, for example, along the YZ-plane, the second deflector150that deflects the collimated light beam in another plane, for example, along the XY-plane, and a fixing member280directly fixing both the first deflector and the second deflector.

The fixing member280includes two convex portions protruding upward from a base282, a support284and a second deflector fixing stand286. The second deflector fixing stand286has the same configuration as the second deflector fixing stand186of the first embodiment. In other words, a second deflector fixing face of the second deflector fixing stand286is inclined by 45 degrees with respect to the YZ-plane around a Z-axis. The second deflector150is as explained in the first embodiment.

The first deflector210comprises two torsion hinges214extending from the fixing member280along the first axis A1, an oscillation member212supported by the torsion hinges214, and the light radiating portion120attached to the oscillation member212. The configuration of the light radiating portion120is as explained in the first embodiment. Although not shown, the first deflector210also comprises a drive mechanism or a drive for oscillatably driving the oscillation member212. For driving the drive, any publicly-known drive such as an electromagnetic drive, an electrostatic drive, a piezoelectric drive, or the like may be adapted.

One torsion hinge214extends from the support284of the fixing member280along the first axis A1, while the other torsion hinge214extends from the second deflector fixing stand286along the first axis A1. The two torsion hinges214are disposed coaxially so that their center axes are aligned with each other. The two torsion hinges214oscillatably support the oscillation member212around the first axis A1with respect to the fixing member280.

The oscillation member212has an extension216extending frontward, that is, in a +X direction parallel to the first axis A1, at the end on the upper side, that is, on a +Y direction side, and the light radiating portion120is provided at the distal end of the extension216. As in the first embodiment, the extension216has a cladding fixing portion fixing a cladding of an optical fiber130, which is a light guide. Although not shown, the cladding fixing portion provided in the extension216has the same structure as the cladding fixing portion116explained in the first embodiment.

The oscillation member212further has an adjusting extension218extending parallel to the first axis A1in the backward direction, that is, in a −X direction, and parallel to the first axis A1in a direction opposite to the extension216, at the end on the lower side, that is, on the side in a −Y direction. The adjusting extension218has the same mechanical characteristics as the extension216. The extension216and the adjusting extension218are symmetrically disposed with respect to a point on the first axis A1. That is, the extension216and the adjusting extension218are positioned on opposite sides with reference to the first axis A1, and extend in mutually opposite directions.

Since the adjusting extension218is also formed at the end of the oscillation member212on the side opposite to the side on which the light radiating portion120is provided in the above manner, the oscillation member212is configured to have the same moment of inertia on both sides thereof, with the center at the center axis of the torsion hinge214.

In the two-dimensional light deflector200of the present embodiment, the oscillation axis of the first deflector210extends on the first axis A1, the oscillation axis of the reflecting face152of the second deflector150is located on the third axis A3, and the third axis A3crosses through a point on the first axis A1and extends perpendicular to the first axis A1.

Similar to the two-dimensional light deflector100of the first embodiment, in the two-dimensional light deflector200of the present embodiment, such configuration allows the collimated light beam radiated from the light radiating portion120to always fall on the reflecting face152of the second deflector150on its oscillation axis. The collimated light beam reflected by the reflecting face152of the second deflector150is deflected along the YZ-plane by the oscillation member212of the first deflector210oscillating around the first axis A1, and is deflected along the XY-plane by the reflecting face152of the second deflector150oscillating around the third axis A3.

In the same manner as in the two-dimensional light deflector100of the first embodiment, the two-dimensional light deflector200of the present embodiment can achieve a raster scan with a substantially rectangular scanning surface, in the same manner as in the two-dimensional light deflector500of the conventional example, in which a deflector is mounted on another deflector, disclosed in U.S. Pat. No. 4,838,632. On the other hand, since the elements mounted on the oscillation member212are only the optical fiber130, the collimating lens122, and the prism124, which are compact and lightweight, the moment of inertia of the oscillating member212is greatly reduced as compared to the two-dimensional light deflector500of the conventional example. Therefore, even when securing the same responsiveness as the two-dimensional light deflector500of the conventional example, the driving force required thereby is greatly reduced, so that the power consumption required for oscillation is greatly reduced. In addition, as the driving force is reduced, the volume required for driving is also reduced, which enables to achieve significant downsizing from the two-dimensional light deflector500of the conventional example.

Furthermore, the two-dimensional light deflector200of the present embodiment has a configuration that is more robust against external forces than the two-dimensional light deflector100of the first embodiment. In the case where the first deflector110includes the cantilever112as in the first embodiment, strong vibration from the outside may cause unexpected oscillation of the collimated light beam from the optical fiber130. On the contrary, in the present embodiment, since the oscillation member212is balanced with the same moment of inertia on both sides, with the torsion hinge214at the center, it is difficult for unexpected oscillation to occur due to external vibration. Therefore, the two-dimensional light deflector200according to the present embodiment, in which the first deflector210includes the oscillation member212, has a configuration with higher robustness against external forces as compared to the two-dimensional light deflector100of the first embodiment, in which the first deflector110includes the cantilever112.

Third Embodiment

FIG. 14andFIG. 15respectively show a side view and a top view of a two-dimensional light deflector according to a third embodiment of the present invention. InFIG. 14andFIG. 15, members denoted by the same reference numerals as those shown inFIG. 1toFIG. 3are the same members, for which detailed explanations will be omitted. The following explanations will be provided while placing importance on the parts different from those inFIG. 1toFIG. 3. That is, portions not mentioned in the following explanation are the same as those in the first embodiment.

A two-dimensional light deflector300of the present embodiment comprises a galvano deflector312in the same manner as the two-dimensional light deflector500of the conventional example disclosed in U.S. Pat. No. 4,838,632. However, the second deflector150is not mounted on the galvano deflector312.

The two-dimensional light deflector300comprises a first deflector310that deflects a collimated light beam in a plane, for example, along the YZ-plane, the second deflector150that deflects the collimated light beam in another plane, for example, along the XY-plane, and a fixing member380directly fixing both the first deflector and the second deflector.

The fixing member380includes two convex portions protruding upward from a base382, a first deflector fixing stand384and a second deflector fixing stand386. The second deflector fixing stand386has the same configuration as the second deflector fixing stand186of the first embodiment. That is, a second deflector fixing face of the second deflector fixing stand386is inclined by 45 degrees with respect to the YZ-plane around the Z-axis. The second deflector150is as explained in the first embodiment.

The first deflector310comprises the galvano deflector312fixed to the first deflector fixing stand384. The galvano deflector312has a rotating shaft312athat is oscillatable around the first axis A1. The first deflector310further comprises an optical fiber fixing jig314fixing an optical fiber, which is a light guide attached to the rotating shaft312aof the galvano deflector312, and the light radiating portion120provided on the optical fiber fixing jig314.

The optical fiber fixing jig314has an extension316extending parallel to the first axis A1. The light radiating portion120is provided at a distal end of the extension316. The light radiating portion120includes the optical fiber130inserted and fixed in a through hole formed at the distal end of the extension316, and the collimating lens122provided at a distal end of the optical fiber130.

Although not shown in detail inFIG. 14andFIG. 15, the extension316includes a cladding fixing portion320fixing the cladding of the optical fiber130. As in the first embodiment, the cladding fixing portion320has a cavity in which the cladding of the optical fiber130is fitted and is accommodated. The cavity is configured by, for example, a groove or a through hole. The optical fiber130is fixed to the optical fiber fixing jig314by inserting the cladding into the cavity formed in the extension316and then adhering the same. The cavity in which the cladding of the optical fiber130is accommodated penetrates a distal end of the extension316, and extends toward the first axis A1. Therefore, the collimated light beam radiated from the light radiating portion120always passes through the first axis A1.

The optical fiber fixing jig314further has an adjusting extension318on a portion opposite to the extension316with reference to the first axis A1. The adjusting extension318has the same mechanical characteristics as the extension316, for example, the weight, and is designed so that the moment of inertia is balanced with the center at an oscillation axis. The adjusting extension318may be of course adjusted in the moment of inertia by changing the thickness.

The second deflector150is disposed so that the oscillation axis of the reflecting face152crosses through a point on the first axis A1. Therefore, the collimated light beam radiated from the optical fiber130is configured to falls on an intersection point of the oscillation axis of the galvano deflector312and the oscillation axis of the second deflector150. Although a direction in which the collimated light beam falls on the reflecting face152of the second deflector150varies depending on the oscillation of the galvano deflector312, a position on the reflecting face152of the second deflector150on which the collimated light beam falls does not change. The collimated light beam reflected by the reflecting face152of the second deflector150is deflected along the ZX-plane by the first deflector310, that is, by an oscillation of the optical fiber fixing jig314, and is deflected along an XY-plane by the second deflector150, that is, by an oscillation of the reflecting face152. Therefore, combining these oscillations allows the collimated light beam reflected by the reflecting face152of the second deflector150to be two-dimensionally scanned. Here, the galvano deflector312is adapted for a low-speed scan and the second deflector150is adapted for a high-speed scan, which achieves a favorable raster scan.

With the above configuration, in the same manner as the first and second embodiments, a raster scan with a substantially rectangular scanning surface can be achieved in the same manner as the two-dimensional light deflector500of the conventional example, in which a deflector is mounted on another deflector, disclosed in U.S. Pat. No. 4,838,632. On the other hand, since the elements mounted on the galvano deflector312are only the optical fiber fixing jig314, the optical fiber130, and the collimating lens122, which are small and lightweight, the moment of inertia applied to the rotating shaft312aof the galvano deflector312is greatly reduced as compared to the two-dimensional light deflector500of the conventional example. Therefore, even when securing the same responsiveness as the two-dimensional light deflector500of the conventional example, the driving force required thereby is greatly reduced, so that the power consumption required for oscillation is greatly reduced.

The configuration of the two-dimensional light deflector300according to the present embodiment is close to the configuration of the conventional two-dimensional light deflector500of the conventional example, in which a second deflector is disposed on a galvano deflector. Furthermore, the galvano deflector312is generally commercially available, and it is easy to switch from the configuration in which the second deflector is disposed on the galvano deflector.

Modified Example

FIG. 16andFIG. 17respectively show a side view and a front view of a modified example of the third embodiment of the present invention. InFIG. 16andFIG. 17, members denoted by the same reference numerals as those shown inFIG. 14andFIG. 15are the same members; therefore, a detailed explanation thereof will be omitted. The following explanations will be provided while placing importance on the parts different from those inFIG. 14andFIG. 15.

A two-dimensional light deflector300A of the present modified example is provided with a first deflector310A instead of the first deflector310shown inFIG. 14andFIG. 15. The first deflector310A comprises an optical fiber fixing jig314A instead of the optical fiber fixing jig314shown inFIG. 14andFIG. 15.

In the two-dimensional light deflector300A of the present modified example, the optical fiber fixing jig314A has an extension316A extending parallel to the first axis A1. A light radiating portion120is provided at a distal end of the extension316A.

Although not shown in detail inFIG. 16andFIG. 17, the extension316A has a cladding fixing portion320A fixing the cladding of the optical fiber130. As in the first embodiment, the cladding fixing portion320A has a cavity in which the cladding of the optical fiber130is fitted and is accommodated. The cavity is configured by, for example, a groove or a through hole. The optical fiber130is fixed to the optical fiber fixing jig314A by inserting the cladding into the cavity formed in the extension316A and then adhering the same. The cavity accommodating the cladding of the optical fiber130extends parallel to the first axis A1near at least a distal end of the extension316A.

The light radiating portion120comprises the collimating lens122that shapes light radiated from the optical fiber130into a collimated light beam, and the prism124that deflects the collimated light beam radiated from the collimating lens122along the first axis A1toward a reflecting face along the second axis A2. The light radiating portion120is configured in the same manner as in the first embodiment.

In the two-dimensional light deflector300A of the present modified example, the cavity316afor installing the optical fiber130is longer than that of the two-dimensional light deflector300shown inFIG. 14andFIG. 15. Therefore, the reproducibility of the direction of the collimated light beam radiated from the optical fiber130is improved; the optical fiber130can be easily fixed in a desired direction, and the assemblability is improved.