JP5049904B2 - Movable structure and optical scanning mirror using the same - Google Patents

Description

  The present invention relates to a movable structure having a movable plate that is pivotally supported by a hinge and configured to be swingable, and an optical scanning mirror using the movable structure.

  2. Description of the Related Art Conventionally, optical devices such as barcode readers and projectors that use an optical scanning mirror that swings a movable plate provided with a mirror surface and scans a light beam incident on the mirror surface are known. (For example, refer to Patent Document 1). As a light scanning mirror, for example, a small one having a movable structure formed by using a micromachining technique is known. Such a movable structure has a movable plate on which a mirror surface is formed when used as an optical scanning mirror, and a fixed frame that supports the movable plate. The movable plate and the fixed frame are connected to each other by a hinge. When a driving force is applied to the movable plate, the movable plate rotates with respect to the fixed frame while twisting the hinge, and swings about the hinge. Examples of the driving force include an electrostatic force generated by applying a voltage to a pair of interdigitated electrodes formed between the movable plate and the fixed frame, a force generated by a piezoelectric effect, an electromagnetic force, and the like. Used.

  By the way, in such an optical scanning mirror, in order to generate a driving force with a small driving voltage and secure a deflection angle necessary for scanning the light, the hinge is thinned and the spring constant in the torsion direction of the hinge is set. Just make it smaller. However, when the hinge is thinned in this way, the hinge becomes brittle. Therefore, when the movable plate is displaced when an impact is applied from the outside and the amount of deformation of the hinge increases, the hinge may be damaged, and the optical scanning mirror may become inoperable.

Note that Patent Document 1 discloses a micromirror device in which a pivot capable of supporting a central portion serving as a center of inclination of a movable plate is formed. However, this micromirror device has a problem that it is difficult to manufacture because the pivot needs to be accurately formed at a predetermined position so as to correspond to the central portion of the movable plate and close to the movable plate. is there.
JP 2003-57575 A

  The present invention has been made in view of the above problems, and can be easily manufactured. The movable structure has a high impact resistance in which a hinge is prevented from being damaged when an impact is applied from the outside. An object of the present invention is to provide an optical scanning mirror using the.

In order to achieve the above object, the invention of claim 1 is directed to a movable plate, a pair of hinges each having one end connected to the movable plate and constituting one swinging shaft of the movable plate, and the pair of hinges. Each of the other end portions is connected to a frame portion that supports the hinge, and the movable plate is configured to be swingable with respect to the frame portion while twisting the pair of hinges. In both sides of the hinge, a stopper portion is formed so as to protrude from the movable plate or the frame portion along the hinge, and when the movable plate is displaced , the stopper portion, Other parts of the movable structure excluding the hinge are in contact with each other, and the amount of displacement of the movable plate in a direction parallel to the upper surface of the movable plate is limited .

According to a second aspect of the present invention, in the first aspect of the present invention, the movable plate is provided with a recess formed so as to be recessed in the longitudinal direction of the hinge in the vicinity of a portion pivotally supported by the hinge. The stopper portion is formed integrally with the frame portion, and is formed so as to be positioned between the hinge and a side edge portion of the movable plate forming the concave portion .

According to a third aspect of the present invention, in the first aspect of the present invention, the movable plate protrudes toward the fixed frame at a position farther from the hinge than the stopper portion on both sides of the hinge. It has the contact protrusion formed .

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, a chamfered portion having an R chamfered shape is formed at a corner portion of the stopper portion.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the stopper portion is configured to have the same potential as the hinge portion.

  According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, at least a part of the stopper portion is prevented from sticking to a portion in contact with the stopper portion. A sticking prevention film or a protrusion is formed.

  A seventh aspect of the invention includes the movable structure according to any one of the first to sixth aspects, wherein a mirror surface that reflects incident light is provided on an upper surface of the movable plate. is there.

  According to the first aspect of the present invention, for example, even when an impact from the outside is applied to the movable structure and the movable plate is displaced laterally, the stopper portion comes into contact with the other part to cause the movable plate to move laterally. The amount of displacement is limited. Accordingly, the movable plate is not greatly displaced and the hinge is prevented from being damaged, so that the impact resistance of the movable structure can be improved. Since the stopper portion is disposed in the vicinity of the hinge, even when the movable plate is inclined with respect to the frame portion, the lateral displacement of the movable plate can be effectively limited. In addition, since the degree of accuracy required for the position and shape of the stopper portion is low compared to the case of forming pivot-like protrusions and the like as in the prior art, the movable structure can be manufactured relatively easily. Since the stopper portion does not contact the hinge, the hinge can be reliably prevented from being damaged.

  According to the second aspect of the present invention, when the member constituting the movable plate or the frame portion is processed to form the movable plate or the frame portion, the stopper portion can be easily formed, and the movable structure can be manufactured more easily. Is possible.

  According to the invention of claim 3, when the movable plate is displaced, the amount of displacement of the movable plate can be limited by the stopper portion coming into contact with the side edge portion of the recess. Therefore, the structure for limiting the displacement amount of the movable plate can be configured more easily and robustly.

  According to the invention of claim 4, since the pointed shape disappears in the portion of the stopper portion that contacts the other portion of the movable structure when the movable plate is displaced, when the portion that contacts the stopper portion and the stopper portion comes into contact with each other It becomes difficult for stress to concentrate on these parts. Accordingly, it is possible to prevent damage to a portion that contacts the stopper portion or the stopper portion of the movable structure.

  According to the fifth aspect of the invention, even if the movable plate is displaced laterally and the stopper portion comes into contact with another part of the movable structure, sticking due to electrostatic attraction occurs and the movable plate cannot swing. This can be prevented.

  According to the invention of claim 6, even if the movable plate is displaced laterally and the stopper portion comes into contact with another part of the movable structure, the sticking prevention film or the protrusion prevents the sticking from occurring. Can be prevented from swinging.

  According to the invention of claim 7, the impact resistance of the optical scanning mirror can be improved, and the optical scanning mirror can be easily manufactured.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIGS. 1A, 1B, 2 and 3 show an example of an optical scanning mirror (movable structure) according to the present embodiment. The optical scanning mirror 1 is a small one mounted on an optical device such as a barcode reader, an external screen or the like, or an optical device such as an optical switch, and an external light source (not shown). Has a function of scanning a light beam or the like incident from.

  First, the configuration of the optical scanning mirror 1 will be described below. The optical scanning mirror 1 is a MEMS (Micro Electro Mechanical System) element manufactured by processing an SOI (Silicon on Insulator) substrate 200 using a so-called micromachining technique or the like. In the SOI substrate 200, for example, a conductive first silicon layer (active layer) 200a and a second silicon layer (substrate layer) 200b are bonded via a silicon oxide film (BOX (Buried OXide) layer) 220. A three-layer substrate. Since the oxide film 220 has an insulating property, the first silicon layer 200a and the second silicon layer 200b are insulated from each other. The thickness of the first silicon layer 200a is, for example, about 30 μm, and the thickness of the second silicon layer 200b is, for example, about 400 μm. As shown in FIG. 1A, the optical scanning mirror 1 is, for example, a rectangular parallelepiped element having a substantially square or rectangular shape with a side of about several mm when viewed from above.

  The optical scanning mirror 1 has a substantially rectangular shape when viewed from above, and a movable plate 2 having a mirror surface 10 formed on the upper surface, and one end of each of the movable plate 2 is connected to both sides of the movable plate 2. A pair of hinges 3 constituting the shaft, a fixed frame (frame part) 4 that surrounds the periphery of the movable plate 2 and supports the other end of each hinge 3, a part of the electrodes 2a of the movable plate 2, A comb-tooth electrode 5 having a part of the electrodes 4 a of the fixed frame 4 and a stopper portion 6 formed on the fixed frame 4 are provided. As shown in FIG. 1B, a gap is provided below the movable plate 2, and the movable plate 2 twists the pair of hinges 3 while using the hinges 3 as swinging axes with respect to the fixed frame 4. And is supported via the hinge 3 so as to be swingable. The pair of hinges 3 are formed such that the axes formed by them pass through the center of gravity of the movable plate 2 when viewed from above. The width of the hinge 3 is, for example, about several micrometers to several tens of micrometers. On the upper surface of the fixed frame 4, voltage application portions 10a and 10b made of, for example, a metal film are formed. The shapes of the movable plate 2 and the mirror surface 10 are not limited to rectangles, but may be other shapes such as a circle. For example, the optical scanning mirror 1 is mounted on the circuit board B or the like by bonding a glass substrate 110 or the like to the lower surface of the fixed frame 4.

  As shown in FIG. 3, the movable plate 2 and the hinge 3 are formed in the first silicon layer 200a. The mirror surface 10 is a thin film made of aluminum, for example, and is formed on the upper surface of the movable plate 2 so as to be able to reflect a light beam incident from the outside. The movable plate 2 is formed in a substantially symmetric shape with respect to a plane perpendicular to the movable plate 2 and passing through the hinge 3, and is configured to swing smoothly around the hinge 3.

  The fixed frame 4 includes a first silicon layer 200a, an oxide film 220, and a second silicon layer 200b. In the present embodiment, a trench 101 is formed in the fixed frame 4 so as to divide the first silicon layer 200a into three portions insulated from each other, for example. The trench 101 is a void formed in a groove shape so as to communicate with the first silicon layer 200a from the upper end to the lower end of the first silicon layer 200a and reach the oxide film 220. Since the trench 101 is formed only in the first silicon layer 200a, the entire fixed frame 4 is integrally formed. The trench 101 is formed at four locations in the fixed frame 4 so that the two support portions 4b respectively connected to the pair of hinges 3 are insulated from other portions. Since the trench 101 is formed, the fixed frame 4 is connected to each of the pair of hinges 3 and has the same potential as the movable plate 2, and two support portions 4 b in which the voltage application portion 10 a is formed on the upper surface, and on the upper surface. Each is divided into two parts where the voltage application part 10b is formed. Since the trench 101 separates the first silicon layer 200a, these portions are insulated from each other. That is, as shown in FIG. 2 with each part having a pattern, the movable plate 2, the hinge 3, and the fixed frame 4 are composed of three parts insulated from each other.

  The electrode 2 a of the comb electrode 5 is formed on the side edge of the movable plate 2 on the free end side to which the hinge 3 is not connected, and the electrode 4 a is the side edge of the movable plate 2 of the fixed frame 4. It is formed in the part facing the part. The electrode 2a and the electrode 4a constituting the comb electrode 5 are formed so as to mesh with each other. The gap between the electrodes 2a and 4a is, for example, about 2 μm to 5 μm.

  The stopper portion 6 is provided in order to limit the amount of displacement in the direction substantially parallel to the upper surface of the SOI substrate 200 on the side of the movable plate 2, that is, substantially perpendicular to the swing axis formed by the hinge 3. As shown in FIG. 2, the stopper portion 6 is formed integrally with the fixed frame 4 on the first silicon layer 200 a, and extends from the fixed frame 4 to the movable plate 2 along the hinge 3 on both sides of the hinge 3. It is projecting toward. In the present embodiment, a portion of the movable plate 2 to which the hinge 3 is connected is provided with a recess 2e formed so as to be recessed in the direction away from the fixed frame 4, that is, the longitudinal direction of the hinge 3. In other words, the hinge 3 is connected to the inner edge of the recess 2 e provided in the movable plate 2. The stopper portion 6 is formed such that a tip portion close to the movable plate 2 is positioned between the side edge portion of the movable plate 2 that forms the hinge 3 and the recess 2e. The stopper portion 6 is formed to have a predetermined gap between the stopper 3 and the hinge 3 so as not to hinder the swinging of the movable plate 2 in a normal state where no external impact is applied to the optical scanning mirror 1. . Therefore, the hinge 3 does not come into contact with the stopper portion 6 and is not damaged. The stopper portion 6 protrudes from the support portion 4b to which the hinge 3 is connected in the fixed frame 4, and the movable plate 2, the hinge 3, and the stopper portion 6 are configured to have the same potential.

  As shown in FIG. 2, a chamfered portion 6 a formed in an R chamfered shape is provided at a corner near the tip of the stopper portion 6. Further, a chamfered portion 2f formed in an R chamfered shape is also provided at a corner portion of the concave portion 2e facing the stopper portion 6. The stopper portion 6 is formed so that the gap between the stopper portion 6 and the recess 2 e of the movable plate 2 is narrower than the gap between the stopper portion 6 and the hinge 3. In the stopper portion 6, a sticking prevention film (not shown) is formed at a portion facing the movable plate 2. The anti-sticking film is provided, for example, by forming a DLC (Diamond Like Carbon) film or a SAM (Self-assembled Monolayer) on a portion of the stopper portion 6 facing the movable plate 2.

  Next, the operation of the optical scanning mirror 1 configured as described above will be described. The movable plate 2 of the optical scanning mirror 1 is driven when the comb electrode 5 generates a driving force at a predetermined driving frequency. The comb-tooth electrode 5 is, for example, a voltage application unit that has the same potential as the electrode 4a when the voltage application unit 10a disposed on the support unit 4b is connected to the ground potential and the electrode 2a of the movable plate 2 is at the reference potential. It is driven by periodically changing the potential of 10b and applying a voltage of a predetermined drive frequency between the electrodes 2a and 4a. When the potentials of the two electrodes 4a of the comb-teeth electrodes 5 are simultaneously changed to a predetermined driving potential (for example, several tens of volts), the two electrodes 2a provided at both ends of the movable plate 2 are respectively Simultaneously attracted to the opposing electrode 4a by electrostatic force. In the optical scanning mirror 1, for example, a pulse voltage having a rectangular wave shape is applied to the comb-teeth electrode 5, and the driving force by the comb-teeth electrode 5 is periodically generated.

  In the present embodiment, the optical scanning mirror 1 is configured to swing the movable plate 2 using, for example, an electrostatic force as a driving force. When a voltage is periodically applied between the electrodes 2a and 4a, an electrostatic attractive force acting in a direction attracting each other is generated between the electrodes 2a and 4a, and this electrostatic attractive force is generated at the free end of the movable plate 2. It acts in a substantially vertical direction with respect to the upper surface of the movable plate 2. That is, when the driving voltage is applied to the comb-tooth electrode 5 from the outside by changing the potentials of the voltage applying units 10a and 10b, torque around the hinge 3 is generated in the movable plate 2 by electrostatic force.

  In such an optical scanning mirror 1, generally, in many cases, an internal stress or the like is generated at the time of molding, so that the movable plate 2 is not in a horizontal posture but is tilted slightly, even in a stationary state. For this reason, even when the comb-tooth electrode 5 is driven even when in a stationary state, a driving force in a direction substantially perpendicular thereto is applied to the movable plate 2 and the movable plate 2 rotates about the hinge 3 as a rotation axis. Then, when the driving force of the comb-tooth electrode 5 is released when the movable plate 2 is in a posture such that the electrodes 2a and 4a are completely overlapped, the movable plate 2 twists the hinge 3 by its inertial force. Continue to rotate. Then, when the inertial force in the rotating direction of the movable plate 2 and the restoring force of the hinge 3 become equal, the rotation of the movable plate 2 in that direction stops. At this time, the comb-tooth electrode 5 is driven again, and the movable plate 2 starts to rotate in the opposite direction to that due to the restoring force of the hinge 3 and the driving force of the comb-tooth electrode 5. The movable plate 2 oscillates repeatedly by such rotation by the driving force of the comb electrode 5 and the restoring force of the hinge 3. The comb electrode 5 is driven by being applied with a voltage having a frequency approximately twice the resonance frequency of the vibration system constituted by the movable plate 2 and the hinge 3, and the movable plate 2 is driven with a resonance phenomenon, and the oscillation thereof. The moving angle is configured to be large. Note that the voltage application mode and the drive frequency of the comb electrode 5 are not limited to those described above. For example, even if the drive voltage is configured to be applied in a sine waveform, the electrodes 2a and 4a It may be configured such that the potentials change in opposite phases.

  Here, since the optical scanning mirror 1 is provided with the stopper portion 6, the optical scanning mirror 1 has high impact resistance compared to the case where the stopper portion 6 is not provided. 4A and 4B show a portion of the optical scanning mirror 1 near the stopper portion 6. As shown in FIG. 4 (a), the hinge 3 is hardly bent and there is a gap between the stopper 6 and the side edge of the recess 2e in a normal state where no impact is applied from the outside. State. At this time, for example, when an external vibration or impact is applied to the optical scanning mirror 1, the movable plate 2 deforms the hinge 3 as shown in FIG. May be displaced toward (indicated by a black arrow). If the displacement amount is further increased, the stopper portion 6 comes into contact with the side edge portion of the recess 2e, so that the displacement of the movable plate 2 in that direction is prevented, and the deformation amount of the hinge 3 does not increase any more. In addition, the hinge 3 does not contact the stopper part 6 until the movable plate 2 is displaced from the normal state and the stopper part 6 contacts the side edge of the recess 2e.

  The optical scanning mirror 1 is manufactured as follows, for example. That is, first, the oxide film 220 is formed on the first silicon layer 200a, and the second silicon layer 200b is bonded to form the SOI substrate 200. Next, the first silicon layer 200a side of the SOI substrate 200 is processed by so-called bulk micromachining technology such as photolithography and etching, so that the movable plate 2, the hinge 3, the fixed frame 4, the comb-tooth electrode 5. Form a shape to be the stopper portion 6 (first step). Thus, by using the bulk micromachining technique, each part of the optical scanning mirror 1 can be easily formed including a fine shape. Thereafter, a metal film is formed on the upper surface of the first silicon layer 200a of the SOI substrate 200 by using a method such as sputtering. By patterning this metal film, the mirror surface 10 is formed on the upper surface of the movable plate 2, and the voltage applying portions 10 a and 10 b are formed on the upper surface of the fixed frame 4.

  Next, the second silicon layer 200b is similarly processed by a bulk micromachining technique to form a shape that becomes the fixed frame 4 (second step). After the first silicon layer 200a and the second silicon layer 200b are processed, the oxide film 220 is etched. For example, etching is performed from the lower surface side of the optical scanning mirror 1 to remove the oxide film 220 at portions other than the fixed frame 4 (third step). As a result, the movable plate 2 is pivotally supported by the fixed frame 4 via the hinge 3, and can be swung with respect to the fixed frame 4. Through the first to third steps, a plurality of optical scanning mirrors 1 are formed on the SOI substrate 200. After the third step, the plurality of optical scanning mirrors 1 formed on the SOI substrate 200 are individually cut. By this series of steps, it is possible to simultaneously manufacture a plurality of optical scanning mirrors 1 and reduce the manufacturing cost of the optical scanning mirrors 1. In addition, the manufacturing process of the optical scanning mirror 1 is not restricted to this, For example, you may shape | mold by laser processing, ultrasonic processing, etc., and may shape | mold one by one. Further, the processing of the second silicon layer 200b may be performed prior to the processing of the first silicon layer 200a.

  As described above, in the present embodiment, since the stopper portion 6 is provided, the movable plate 2 is not greatly displaced, and the hinge 3 is prevented from being damaged. Therefore, the impact resistance of the optical scanning mirror 1 is improved. Can be improved. Since the stopper portion 6 is disposed in the vicinity of the hinge 3, even when the movable plate 2 is inclined with respect to the fixed frame 4, the lateral displacement of the movable plate 2 is effectively limited. This can prevent the breakage of the hinge 3 more reliably. At this time, since the stopper portion 6 does not contact the hinge 3, the hinge 3 can be reliably prevented from being damaged. Since the movable plate 2 is pivotally supported by the hinge 3, the movable plate 2 is not easily displaced in the longitudinal direction of the swing shaft constituted by the hinge 3. Therefore, the amount of displacement of the movable plate 2 in the direction parallel to the upper surface of the SOI substrate 200 can be substantially limited by providing the stopper portion 6 in this way, effectively preventing the hinge 3 from being damaged. can do. Moreover, since the stopper part 6 is supported by the recessed part 2e at the time of the displacement of the movable plate 2, the robust structure for supporting the stopper part 6 can be comprised easily. Furthermore, the stopper portion 6 is provided with a chamfered portion 6a, and the portion that can come into contact with the side edge of the recess 2e is not pointed, and similarly, a chamfered portion 2f is provided at the side edge of the recess 2e. The portion that is provided and can come into contact with the stopper portion 6 is not pointed. Accordingly, it is difficult for stress to concentrate on the contact portion between the stopper portion 6 and the side edge portion of the recess 2e, and damage to the stopper portion 6 and the movable plate 2 can be prevented.

  Further, the stopper portion 6 and the side edge portion of the recess 2e are at the same potential, and a sticking prevention film is disposed on a portion of the stopper portion 6 that can come into contact with the side edge portion of the recess 2e. . Therefore, when the stopper portion 6 and the recess 2e come into contact, sticking due to electrostatic attraction is less likely to occur, and the movable plate 2 can be more reliably prevented from being unable to swing. Furthermore, the stopper portion 6 does not hinder the swinging of the movable plate 2 to the side of the hinge 3 and comes into contact with the concave portion 2e of the movable plate 2 when the movable plate 2 is displaced to the side. Since it is not necessary to position the stopper portion 6 with high accuracy, the optical scanning mirror 1 can be manufactured relatively easily. In particular, in the present embodiment, since the stopper portion 6 can be formed at the same time in the process of forming the fixed frame 4 by processing the first silicon layer 200a, an appropriate distance between the stopper portion 6 and the fixed frame 4 is set. It can be easily secured and can be easily manufactured.

  Next, a second embodiment of the present invention will be described. FIG. 5 shows an optical scanning mirror 21 according to the second embodiment. Hereinafter, the same components as those in the first embodiment described above are denoted by the same reference numerals, and only the portions different from those in the first embodiment will be described. The optical scanning mirror 21 has a movable plate 22 having a shape different from that of the movable plate 2 of the optical scanning mirror 1. That is, as shown in the figure, the movable plate 22 does not have the concave portion 2e, and protrudes toward the fixed frame 4 at positions on both sides of the hinge 3 that are further from the hinge 3 than the stopper portion 6. It has the contact protrusion 22e formed so that it may do. The other configuration of the movable plate 22 and the configuration of the optical scanning mirror 21 other than the movable plate 22 are the same as those of the optical scanning mirror 1 of the first embodiment. The optical scanning mirror 21 can also be easily manufactured by forming a shape including the contact protrusion 22e by processing the first silicon layer 200a by a bulk micromachining technique.

  6A and 6B show a portion of the optical scanning mirror 21 in the vicinity of the stopper portion 6. Each of the two contact protrusions 22e is disposed so as to be close to the side portion of the stopper portion 6 at a position closer to the hinge 3 than the contact protrusion 22e. As shown in FIG. 6A, in a normal state, the gap between the stopper portion 6 and the contact protrusion 22e is configured to be slightly narrower than the gap between the stopper portion 6 and the hinge 3. ing. Also, a chamfered portion 22f having an R chamfer shape is formed at a corner portion of the contact protrusion 22e on the stopper portion 6 side. As shown in FIG. 6B, when the movable plate 22 is displaced laterally, the one stopper portion 6 and the contact protrusion 22e come into contact with each other, and the movable plate 22 is not displaced further. Therefore, also in this embodiment, similarly to the first embodiment described above, the hinge 3 can be prevented from being damaged, and the impact resistance of the optical scanning mirror 21 can be improved. Since the stopper portion 6 does not contact the hinge 3, the hinge 3 can be reliably prevented from being damaged. Since the stopper portion 6 and the contact protrusion 22e have the same potential, sticking hardly occurs when the stopper portion 6 and the contact protrusion 22e come into contact with each other, and the optical scanning mirror 21 can be operated more reliably. Can be maintained.

  FIG. 7 shows an optical scanning mirror 41 according to the third embodiment of the present invention. The optical scanning mirror 41 includes a movable plate 42 having a stopper portion 46 formed along the hinge 3 in place of the movable plate 2 of the optical scanning mirror 1. In addition, a contact protrusion 44 e is provided on the support portion 4 b of the fixed frame 4. The contact protrusions 44e are formed so as to protrude toward the movable plate 42 on both sides of the hinge 3 and at a position farther from the hinge 3 than the stopper portion 46, respectively. The configuration of the optical scanning mirror 41 other than the movable plate 42 and the contact protrusion 44e is the same as that of the optical scanning mirror 1 of the first embodiment. The optical scanning mirror 41 can also be easily manufactured by forming the shape including the movable plate 42 and the contact protrusion 44e by processing the first silicon layer 200a by the bulk micromachining technique.

  8A and 8B show the vicinity of the stopper portion 46 in the optical scanning mirror 41. FIG. The two contact protrusions 44e are arranged so as to be close to the side portion of the stopper portion 46 at a position closer to the hinge 3 than the contact protrusion 44e. As shown in FIG. 6A, in a normal state, the gap between the stopper portion 46 and the contact protrusion 44e is configured to be slightly narrower than the gap between the stopper portion 46 and the hinge 3. ing. The contact protrusion 44e and the stopper portion 46 include a chamfered portion 44f and a chamfered portion 46a, respectively, similarly to the chamfered portion 2f for the concave portion 2e of the optical scanning mirror 1 and the chamfered portion 6a for the stopper portion 6. Is formed. As shown in FIG. 6B, when the movable plate 42 is displaced laterally, one stopper portion 46 and the contact protrusion 44e come into contact with each other, and the movable plate 42 is not displaced any more. Therefore, also in the present embodiment, similarly to the first and second embodiments described above, the hinge 3 can be prevented from being damaged and the impact resistance of the optical scanning mirror 41 can be improved. Moreover, since the stopper part 46 does not contact the hinge 3, the damage of the hinge 3 can be prevented reliably. Furthermore, since the chamfered portion 44f is formed on the contact projection 44e and the chamfered portion 46a is formed on the stopper portion 46, the stopper portion 46 and the contact projection 44e can be prevented from being damaged. it can.

  FIG. 9 shows the vicinity of the stopper 56 of the optical scanning mirror according to the fourth embodiment of the present invention. In the fourth embodiment, the entire configuration of the optical scanning mirror is the same as that of the optical scanning mirror 1 of the first embodiment, and a description thereof will be omitted. In the fourth embodiment, instead of the stopper portion 6 provided with the anti-sticking film, a stopper portion 56 formed with a protrusion 56c is provided. As shown in the figure, the protrusion 56c is provided in a sawtooth shape, for example, when viewed from above, and a portion of the stopper 56 that contacts the side edge of the recess 2e when the movable plate 2 is displaced. Is provided.

  In 4th Embodiment, since the projection part 56c is provided in the stopper part 56, when the stopper part 56 and the side edge part of the recessed part 2e contact, a mutual contact area decreases. As a result, the influence of electrostatic attraction between the stopper portion 56 and the recess 2e is reduced, and sticking is prevented from occurring. The shape of the protrusion 56c is not limited to the sawtooth shape. The protrusion 56c is preferably formed in a shape such that stress does not concentrate too much on the contact portion when the stopper 56 contacts the recess 2e. Furthermore, in the fourth embodiment, an anti-sticking film may be further formed on a portion where the stopper portion 56 and the side edge of the recess 2e can come into contact with each other, thereby more reliably preventing the occurrence of sticking. be able to.

  In addition, this invention is not limited to the structure of the said embodiment, A various deformation | transformation is possible suitably in the range which does not change the meaning of invention. For example, the optical scanning mirror is not swingable about one axis as in the above embodiment, but has a movable frame (frame portion) pivotally supported with respect to a fixed frame, for example. On the other hand, it may be of a biaxial gimbal type in which a mirror portion provided with a mirror surface so as to be swingable is supported. In this case, the amount of displacement of the movable plate including the movable frame and the mirror portion can be limited by forming the stopper portion along the hinge on which the movable frame is pivotally supported. Similarly, the amount of displacement of the mirror portion as the movable plate with respect to the movable frame can be limited by forming the stopper portion along the hinge on which the mirror portion is pivotally supported. Further, the optical scanning mirror may be composed of a single silicon substrate or a metal plate instead of the SOI substrate, and the driving force for swinging the movable plate is not the electrostatic force acting between the comb electrodes. Further, it may be an electrostatic force acting between the plate electrodes, electromagnetic force, electrostrictive force, or thermal strain force. Furthermore, the stopper portion may not be formed integrally with the movable plate or the frame portion, and may be arranged so as to be able to limit the displacement amount of the movable plate apart from the movable plate or the frame portion. In either case, by forming the stopper part on the side of the hinge that pivotally supports the movable plate, the displacement of the movable plate to the side can be limited, preventing damage to the hinge. In addition, the impact resistance of the optical scanning mirror can be improved.

  Furthermore, the present invention is not limited to an optical scanning mirror having a mirror surface and scanning light, but a movable structure in which a movable plate configured to be swingable with respect to a fixed frame by a pair of hinges is formed on a semiconductor substrate. Widely applicable to the body. That is, the impact resistance of the movable structure can be improved by providing the stopper portion along the hinge on the side of the hinge.

(A) is a perspective view which shows the upper surface side of the optical scanning mirror which is a movable structure which concerns on 1st Embodiment of this invention, (b) is a perspective view which shows the lower surface side of the optical scanning mirror. The top view of the said optical scanning mirror. FIG. 3 is a sectional view taken along line AA in FIG. 2. (A) is a top view which shows the stopper part vicinity part of the said optical scanning mirror, (b) is a top view which shows the same part when a movable plate displaces from normal. The perspective view which shows the optical scanning mirror which concerns on 2nd Embodiment of this invention. (A) is a top view which shows the stopper part vicinity part of the said optical scanning mirror, (b) is a top view which shows the same part when a movable plate displaces from normal. The perspective view which shows the optical scanning mirror which concerns on 3rd Embodiment of this invention. (A) is a top view which shows the stopper part vicinity part of the said optical scanning mirror, (b) is a top view which shows the same part when a movable plate displaces from normal. The top view which shows the stopper part vicinity site | part of the optical scanning mirror which concerns on 4th Embodiment of this invention.

Explanation of symbols

1, 21, 41 Optical scanning mirror (movable structure)
2, 22, 42 Movable plate 2e Recess 3 Hinge 4 Fixed frame (frame part)
6, 46, 56 Stopper 6a, 46a Chamfer 10 Mirror surface 56c Projection

Claims (7)

A movable plate, a pair of hinges each having one end connected to the movable plate and constituting one swing shaft of the movable plate, and the other ends of the pair of hinges are connected to support the hinge And a frame part
In the movable structure in which the movable plate is configured to be swingable with respect to the frame portion while twisting the pair of hinges,
A stopper portion is formed on both sides of the hinge so as to protrude from the movable plate or the frame portion along the hinge, and when the movable plate is displaced , the stopper portion and the hinge A movable structure characterized in that a displacement amount of the movable plate in a direction parallel to the upper surface of the movable plate is limited by contact with other parts of the movable structure except for the above . The movable plate is provided with a recess formed to be recessed in the longitudinal direction of the hinge in the vicinity of the portion pivotally supported by the hinge.
The said stopper part is integrally formed in the said frame part, and is formed so that it may be located between the hinge and the side edge part of the movable plate which forms the said recessed part. The movable structure described in 1.   The movable plate has contact protrusions formed on both sides of the hinge at positions farther from the hinge than the stopper, respectively, so as to protrude toward the fixed frame. Item 10. A movable structure according to Item 1.   The movable structure according to any one of claims 1 to 3, wherein a chamfered portion having an R chamfered shape is formed at a corner portion of the stopper portion.   The said stopper part is comprised so that it may become the same electric potential as the other site | part of the movable structure which contacts the said stopper part when the said movable plate displaces to a side. Item 5. The movable structure according to any one of Items 4.   The sticking prevention film or the projecting portion is formed on at least a part of the stopper portion so as not to cause sticking between the stopper portion and a portion in contact with the stopper portion. The movable structure according to claim 5. The movable structure according to any one of claims 1 to 6,
An optical scanning mirror characterized in that a mirror surface for reflecting incident light is provided on the upper surface of the movable plate.

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