JP5053194B2 - 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 is driven by a comb-shaped electrode provided between a hinge and a frame, 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. As the driving force, for example, an electrostatic force generated by applying a voltage to a pair of interdigitated electrodes formed between the movable plate and the fixed frame is used.

By the way, the comb electrode used in such an optical scanning mirror is composed of a large number of comb teeth formed to be extremely thin in order to generate a large electrostatic force. When vibration or impact is applied to the optical scanning mirror from the outside and the amount of displacement to the side of the movable plate increases, the comb teeth provided on the movable plate come into contact with the fixed frame or the like. The comb teeth are in contact with the movable plate. Since each comb tooth is thin and fragile, contact with the fixed frame, the movable plate, or the like in this way may cause damage.
JP 2004-13099 A

  The present invention has been made in view of the above problems, and can be easily manufactured, and even when an external impact is applied, the comb electrode is not easily damaged and has a high impact resistance. An object is to provide an optical scanning mirror using the same.

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 swing shaft of the movable plate, and a periphery of the movable plate. And the other end of each of the pair of hinges is connected so that the frame part supporting the hinges, a part of the movable plate and a part of the frame part opposed to the frame part engage with each other. In a movable structure including a comb-shaped electrode that is formed and swings the movable plate with respect to the frame portion , when the movable plate is displaced, it contacts other parts of the movable structure excluding the comb-shaped electrode And a stopper portion disposed so as to limit the amount of displacement of the movable plate in a direction parallel to the upper surface of the movable plate, and the stopper portion is arranged when the movable plate is displaced laterally. Possible to contact the stopper Are those configured such that the other parts the same potential of the structure.

  According to a second aspect of the present invention, in the first aspect of the present invention, the stopper portion is formed integrally with the movable plate or the frame portion.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, an R chamfered chamfered portion is formed at a corner of the stopper portion.

According to a fourth aspect of the present invention, in the invention according to any one of the first to third 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 .

According to a fifth aspect of the present invention, the movable structure according to any one of the first to fourth aspects is provided, and a mirror surface that reflects incident light is provided on the upper surface of the movable plate. .

  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 move the movable plate to the side. The amount of displacement is limited. Therefore, since the comb teeth of the comb-tooth electrode do not come into contact with the movable plate, the frame portion, etc., the comb-tooth electrode is prevented from being damaged, and the impact resistance of the movable structure can be improved. Since the impact resistance can be improved simply by providing the stopper portion in the vicinity of the comb electrode, the movable structure can be manufactured relatively easily.

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

  According to the invention of claim 3, 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, the stopper portion and the portion that contacts the stopper portion come 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 fourth aspect of the present 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 be swung. This can be prevented.

  According to the invention of claim 5, even if the movable plate is displaced to the side and the stopper portion comes into contact with another part of the movable structure, the occurrence of sticking is prevented by the sticking prevention film or the protrusion, It is possible to prevent the movable plate from becoming unable to swing.

  According to invention of Claim 6, the impact resistance of an optical scanning mirror can be improved, and an optical scanning mirror can be manufactured easily.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1, 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. As shown in FIG. 1, an SOI substrate 200 includes, for example, a conductive first silicon layer (active layer) 200a and a second silicon layer (substrate layer) 200b formed of a silicon oxide film (BOX (Buried OXide) layer). 3) a substrate having a three-layer structure. 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. 2, 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 millimeters 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 electrode 5 having a part of the electrodes 4 a of the fixed frame 4 and a stopper portion 6 formed on the movable plate 2 are provided. As shown in FIG. 3, a gap is provided below the movable plate 2, and the movable plate 2 swings with respect to the fixed frame 4 using the hinges 3 as swinging shafts while twisting the pair of hinges 3. It is supported via the hinge 3 as possible. 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 has a total of four locations on each side of the two comb electrodes 5 so that the two support portions 4b connected to the pair of hinges 3 in the fixed frame 4 are insulated from other portions. Is formed. The two support parts 4b are formed so that it may be located in the part which opposes the peripheral part except the site | part in which the electrode 2a is formed among the movable plates 2 so that it may mention later.

  Since the trench 101 is formed in this way, 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 each having a voltage application portion 10 a formed on the upper surface thereof. The voltage application part 10b is formed on the upper surface and divided into two parts having the electrode 4a. 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. Each of the electrode 2a and the electrode 4a has a plurality of comb teeth. The comb teeth of the electrode 2a and the electrode 4a are formed so as to be as thin as possible in a limited space for providing the comb electrode 5. The electrode 2a and the electrode 4a are formed so that the comb teeth 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 movable plate 2 in the first silicon layer 200a. In the present embodiment, the stopper portion 6 protrudes from the four corners of the movable plate 2 located outside the arrangement direction of the comb-tooth electrodes 5 toward the fixed frame 4 facing the portion of the movable plate 2. . The stopper portion 6 is formed such that the tip portion close to the fixed frame 4 is close to the support portion 4 b of the fixed frame 4. The stopper portion 6 is formed so as not to hinder the swinging of the movable plate 2 in normal times when no external impact is applied to the optical scanning mirror 1. The stopper portion 6 projects from the fixed frame 4 toward the support portion 4b, 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. The stopper portion 6 is configured such that the gap between the stopper portion 6 and the support portion 4b is narrower than the gap between the electrode 2a and the fixed frame 4 or the gap between the electrode 4a and the movable plate 2. Is formed. 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. FIG. 4 shows the vicinity of the stopper portion 6. In a normal state in which no impact or the like is applied to the optical scanning mirror 1 from the outside, a state in which there is a gap between each stopper portion 6 and the support portion 4b facing each of them is maintained. 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 while deforming the hinge 3 as shown in FIG. It may be displaced in the direction perpendicular to the upper surface of the SOI substrate 200 (in the direction of the arrow in the figure). When the amount of displacement of the movable plate 2 to the side increases, the stopper portion 6 contacts the side edge of the support portion 4b, so that the displacement of the movable plate 2 in that direction is hindered, and the amount of displacement further increases. Nothing will happen. In the state where the stopper portion 6 is in contact with the side edge portion of the support portion 4b, the comb teeth of the electrode 2a do not contact the fixed frame 4, and the comb teeth of the electrode 4a do not contact the movable plate 2. Protected.

  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 displacement amount of the movable plate 2 is limited and the comb electrode 5 is prevented from being damaged. Impact properties can be improved. 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 displacement amount of the movable plate 2 in the direction parallel to the upper surface of the SOI substrate 200 can be substantially limited by providing such a stopper portion 6, and the comb-teeth electrode 5 is effectively damaged. Can be prevented. Further, the stopper portion 6 is provided with an R chamfered chamfered portion 6a, and the portion that can come into contact with the fixed frame 4 is not pointed, so that stress concentrates on the contact portion between the stopper portion 6 and the fixed frame 4. This makes it difficult to prevent the stopper 6 and the fixed frame 4 from being damaged.

  Further, the stopper portion 6 and the support portion 4b of the fixed frame 4 have the same potential, and a sticking prevention film is disposed on a portion of the stopper portion 6 that can contact the support portion 4b. Therefore, when the stopper portion 6 and the support portion 4b come into contact with each other, 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, since the stopper portion 6 can be formed integrally with the movable plate 2, the optical scanning mirror 1 can be manufactured relatively easily. In particular, in the present embodiment, the stopper portion 6 is formed at the same time in the process of forming the movable plate 2 by processing the first silicon layer 200a, so that an appropriate interval between the stopper portion 6 and the fixed frame 4 can be easily secured. Can be manufactured easily.

  In the first embodiment, sticking may be prevented by forming a protrusion on the stopper. FIG. 5 shows an example of a stopper portion having a protrusion. A serrated projection 16a is formed at a portion of the stopper portion 16 that can come into contact with the fixed frame 4 when the movable plate 2 is displaced laterally. Thus, since the protrusion part 16a is provided in the stopper part 16, when the stopper part 16 and the fixed frame 4 contact, a mutual contact area decreases. As a result, the influence of electrostatic attraction between the stopper portion 16 and the fixed frame 4 is reduced, thereby preventing the occurrence of sticking. The shape of the protrusion 16a is not limited to the sawtooth shape. The protrusion 16a is preferably formed in a shape such that when the stopper 16 and the fixed frame 4 are in contact, stress is not concentrated too much on the contact portion. Further, when the protrusion 16a is provided on the stopper portion 16 as described above, a sticking prevention film may be further formed on a portion where the stopper portion 16 and the fixed frame 4 can come into contact with each other. It can prevent more reliably.

  Next, a second embodiment of the present invention will be described. FIG. 6 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 circular movable plate 22 and a fixed frame 24 formed so as to surround the movable plate 22, and is formed at substantially the center of the free end of the movable plate 22. Two stopper portions 26 are provided. The fixed frame 24 is separated into three mutually insulated parts by forming the trench 101, but unlike the first embodiment, the fixed frame 4 facing the stopper part 26 is separated from the stopper part 26. It is not made to become the same electric potential. The support portion 24 b of the fixed frame 24 is disposed only at a portion that supports the hinge 3, and is not located at a portion that faces the movable plate 22. Note that the arrangement of the trench 101, the voltage application unit 10b, and the like may be changed so that the fixed frame 4 at a portion facing the stopper unit 26 has the same potential as the stopper unit 26. Other configurations of the optical scanning mirror 21 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 in which the stopper portion 26 is provided on the movable plate 22 by processing the first silicon layer 200a by a bulk micromachining technique.

  As shown in the figure, the comb-tooth electrode 5 is disposed on both side portions of the stopper portion 26 formed substantially at the center of the free end of the movable plate 22 so as to be along the edge portion of the movable plate 22. In other words, the stopper portion 26 is disposed in the vicinity of the side of the comb electrode 5. As in the first embodiment, the stopper portion 26 is movable between the fixed frame 24 and the gap between the electrode 2a of the comb-tooth electrode 5 and the fixed frame 24 or the electrode 4a in the normal state. It is formed to be slightly narrower than the gap between the plate 22. Further, an anti-sticking film is formed at a portion of the stopper portion 26 that can come into contact with the fixed frame 24, and an R chamfered chamfered portion 26a is formed at a corner portion thereof.

  Also in the second embodiment, when an impact, vibration, or the like is applied from the outside and the movable plate 22 is displaced laterally, one stopper portion 26 contacts the fixed frame 24, and the movable plate 22 is not displaced further. Therefore, also in this embodiment, similarly to the first embodiment described above, the comb electrode 5 can be prevented from being damaged and the impact resistance of the optical scanning mirror 21 can be improved. Since the stopper portion 26 is provided with a sticking prevention film, sticking hardly occurs when the stopper portion 26 comes into contact with the fixed frame 24. Further, since the chamfered portion 26a is formed in the stopper portion 26, the stopper portion 26 and the fixed frame 24 can be prevented from being damaged.

  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 stopper portion is not limited to the one provided integrally with the movable plate. For example, the stopper portion is formed integrally with the fixed frame formed to protrude from the fixed frame toward the movable plate in the vicinity of the comb electrode. It may be a thing. Even in this case, when the movable plate is displaced laterally, the stopper portion comes into contact with the movable plate, the displacement amount of the movable plate is limited, and the comb electrode can be protected.

  Further, 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 so as to be swingable with respect to the fixed frame, for example. A biaxial gimbal type in which a mirror portion provided with a mirror surface swingably with respect to the frame is pivotally supported may be used. In this case, by disposing the stopper portion in the vicinity of the comb electrode between the movable frame and the fixed frame, the displacement amount of the movable plate including the movable frame and the mirror portion is limited, and the comb electrode is protected. be able to. Similarly, by forming the stopper part near the comb electrode between the mirror part and the movable frame, the displacement of the mirror part as a movable plate with respect to the movable frame is limited, and the comb electrode is protected. can do. Further, the optical scanning mirror may be composed of a single silicon substrate or a metal plate instead of the SOI substrate. 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 this case as well, the lateral displacement of the movable plate can be limited by forming the stopper portion in the vicinity of the comb electrode between the movable plate and the surrounding frame portion. Can be prevented, and 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 forming the stopper portion in the vicinity of the comb electrode between the movable plate and the frame portion.

The perspective view which shows the optical scanning mirror which is a movable structure which concerns on 1st Embodiment of this invention. The top view of the said optical scanning mirror. FIG. 3 is a sectional view taken along line AA in FIG. 2. The top view which shows the stopper part vicinity site | part of the said optical scanning mirror. The top view which shows the stopper part of the modification of the said optical scanning mirror. The perspective view which shows the optical scanning mirror which concerns on 2nd Embodiment of this invention.

Explanation of symbols

1,21 Optical scanning mirror (movable structure)
2,22 Movable plate 3 Hinge 4,24 Fixed frame (frame part)
5 Comb electrode 6, 16, 26 Stopper 6a, 26a Chamfer 10 Mirror surface 16c Projection

Claims (5)

A movable plate,
A pair of hinges each having one end connected to the movable plate and constituting one swing axis of the movable plate;
A frame portion disposed around the movable plate, connected to the other end of each of the pair of hinges, and supporting the hinges;
In a movable structure including a comb-shaped electrode that is formed so as to mesh with a part of the movable plate and a part of the frame part facing the movable plate and swings the movable plate with respect to the frame part,
When the movable plate is displaced, the movable plate is disposed so as to come into contact with other parts of the movable structure excluding the comb electrode and limit the amount of displacement of the movable plate in a direction parallel to the upper surface of the movable plate. Further provided with a stopper portion,
The movable structure, wherein the stopper portion is configured to have the same potential as other portions of the movable structure that come into contact with the stopper portion when the movable plate is displaced laterally.   The movable structure according to claim 1, wherein the stopper portion is formed integrally with the movable plate or the frame portion.   The movable structure according to claim 1 or 2, wherein a chamfered portion having an R-chamfered shape is formed at a corner portion of the stopper portion.   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. 4. The movable structure according to any one of 3 above. The movable structure according to any one of claims 1 to 4,
An optical scanning mirror characterized in that a mirror surface for reflecting incident light is provided on the upper surface of the movable plate.

Images