JP4983648B2 - Optical scanning device - Google Patents

Description

  The present invention relates to an optical scanning device that scans a light beam.

In recent years, various optical scanning devices using MEMS (Micro Electro Mechanical System) technology have been proposed for the purpose of downsizing the optical scanning device.
On the other hand, the applicant of the present application added the reflecting portion by generating an electrostatic force between the comb teeth provided on both sides of the reflecting portion made of silicon and the comb teeth arranged on the fixed side opposite to the comb teeth. The thing to shake is proposed (for example, refer patent document 1). However, in the technique described in Patent Document 1, the reflective portion and the comb teeth on both sides of the reflective portion vibrate integrally. For this reason, when the angular amplitude of the vibration of the reflecting portion increases, the comb teeth on the reflecting portion (hereinafter referred to as the reflecting portion side comb teeth) and the fixed comb teeth (hereinafter referred to as the fixed side comb teeth) do not face each other. . That is, the excitation does not act between the reflecting portion side comb teeth and the fixed side comb teeth. Therefore, it has been difficult to vibrate the reflecting portion greatly exceeding the angular amplitude at which the reflecting portion side comb teeth and the fixed side comb teeth face each other.

For such a problem, a reflecting portion having a reflecting surface for reflecting the light beam, a first frame that supports the reflecting portion so as to be swingable about a predetermined rotation axis, and the first frame with the predetermined rotation axis. A second frame that is pivotably supported at the center, a first drive mechanism that generates a driving force for swinging the reflecting portion with respect to the first frame, and a first frame that vibrates with respect to the second frame. There has been proposed an optical scanning device including a second driving mechanism that generates a driving force for the purpose (see, for example, Patent Document 2). In the optical scanning apparatus configured as described above, the angular amplitude of the vibration of the reflecting portion is the angular amplitude at which the reflecting portion vibrates with respect to the first frame, and the angular amplitude at which the first frame vibrates with respect to the second frame. The sum of For this reason, the angular amplitude of the vibration of the reflection part can be increased compared with the case where the reflection part is merely vibrated with respect to the first frame.
JP 2004-245890 A Japanese Patent Laid-Open No. 2005-88188

  However, in the technique described in Patent Document 2, a reflection portion is included inside the first frame. In order to vibrate the reflecting portion, in addition to providing a first driving mechanism for vibrating the reflecting portion outside the reflecting portion, a second driving mechanism for further vibrating the first frame is provided on the first frame. Provided outside. As a result, there is a problem that the overall size of the optical scanning device increases. Further, the second drive mechanism needs to vibrate the first frame and the reflecting portion at the same time in order to vibrate the first frame. That is, compared with the case where only the reflecting portion is vibrated, there is a problem that the mass of the object to be vibrated becomes large and the angular amplitude of vibration of the reflecting portion cannot be increased efficiently.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a technique capable of efficiently increasing the angular amplitude of vibration of the reflecting portion while suppressing an increase in the size of the entire optical scanning device. To do.

  In order to achieve the above object, an optical scanning device according to claim 1, further comprising: a reflecting portion having a reflecting surface for reflecting the light beam; and an elastically deformable first elastic connecting portion connected to the reflecting portion. And a first swinging support portion that swingably supports the reflecting portion with the first elastic coupling portion as a first rotation axis, and a first comb-like electrode portion that extends from the reflecting portion and is formed in a comb shape. And a second comb-shaped electrode portion formed in a comb-tooth shape that can mesh with the first comb-shaped electrode portion, and disposed at a position that can mesh with the first comb-shaped electrode portion, By applying a voltage between the tooth-like electrode part and the second comb-like electrode part, the reflecting part is vibrated at the first predetermined frequency by electrostatic attraction generated between the two electrode parts.

The second swing support portion supports the second comb-shaped electrode portion so as to swing about the second rotation shaft having the same axial direction as the first rotation shaft , and the vibration means further includes the second comb teeth. The electrode portion is vibrated with respect to the second swing support portion at a second predetermined frequency.
According to the optical scanning apparatus configured as described above, the vibrating means vibrates the second comb-shaped electrode portion around the second rotation axis having the same axial direction as the first rotation axis. The position of the electrode portion can be changed. Accordingly, the second comb-shaped electrode portion and the second comb-shaped electrode portion are opposed to each other in accordance with the position change of the first comb-shaped electrode portion due to the vibration of the first comb-shaped electrode portion. It becomes possible to change the position of the comb-shaped electrode portion. For this reason, when the reflecting portion is vibrated, the angular amplitude range in which the first comb-shaped electrode portion and the second comb-shaped electrode portion face each other, that is, the first comb-shaped electrode portion and the second comb-shaped electrode portion. The range of the angular amplitude in which electrostatic attraction can be generated between the electrode portion and the electrode portion can be increased as compared with a case where the position of the second comb-shaped electrode portion is not changed. Thereby, the angular amplitude of the vibration of the reflection unit can be increased, and the angle (scanning angle) at which the optical scanning device scans the light beam can be increased.

  The vibration means vibrates the second comb-shaped electrode portion with respect to the second swing support portion supporting the second comb-shaped electrode portion. That is, it is not necessary to vibrate the second swing support part in order to vibrate the second comb-like electrode part. For this reason, it is not necessary to provide the means for vibrating the 2nd comb-like electrode part, ie, the above-mentioned vibrating means outside the 2nd rocking support part. Thereby, the increase in the dimension of the whole optical scanning device can be suppressed.

  Furthermore, it is not necessary to vibrate the first swing support part and the second swing support part in order to vibrate the reflection part. That is, only the reflecting portion needs to be vibrated in order to vibrate the reflecting portion. For this reason, in order to vibrate the reflection part, it is possible to suppress an increase in mass of the object to be vibrated to a minimum and efficiently increase the angular amplitude of vibration of the reflection part.

  In the optical scanning device according to claim 1, as described in claim 2, the first comb-shaped electrode portion and the second comb-shaped electrode portion are disposed on both sides of the reflecting portion with the first rotation axis interposed therebetween. It should be provided.

  According to the optical scanning device configured as described above, electrostatic attraction can be generated on both sides of the reflecting portion across the first rotation axis in order to vibrate the reflecting portion. As a result, the force for vibrating the reflecting portion can be distributed to both sides of the reflecting portion. Therefore, compared with the case where electrostatic attraction is generated only on one side of the reflecting portion across the first rotation axis, The voltage applied between the first comb-shaped electrode portion and the second comb-shaped electrode portion can be reduced. Furthermore, it is possible to apply an electrostatic attractive force evenly on both sides of the reflective portion, and therefore, the reflective portion can be vibrated stably as compared with a case where an electrostatic attractive force is applied only to one side of the reflective portion.

  Further, in the optical scanning device according to claim 1 or 2, as described in claim 3, the vibrating means is not opposed to the first comb-shaped electrode portion in the second comb-shaped electrode portion. Preferably, the piezoelectric element is fixed to one surface, and expansion / contraction means for expanding / contracting the piezoelectric element along a direction in which the second comb-shaped electrode portion extends.

  In the optical scanning device thus configured, the expansion / contraction means moves along one of the piezoelectric elements fixed to the surface of the second comb-shaped electrode portion along the direction in which the second comb-shaped electrode portion extends. By compressing, the second comb-shaped electrode portion is deformed toward the side where the compressed piezoelectric element is fixed. For this reason, by alternately repeating expansion and contraction of the piezoelectric element fixed to the two surfaces that are not opposed to the first comb-shaped electrode portion in the second comb-shaped electrode portion, The second comb-like electrode portion can be vibrated with respect to the second swing support portion along the opposing direction.

  According to the optical scanning device configured as described above, the second comb-shaped electrode portion is vibrated by the expansion and contraction of the piezoelectric element by the expansion / contraction means. Therefore, the second comb-shaped electrode portion is vibrated independently from the vibration of the reflection portion. Can be made.

In the optical scanning device according to any one of the first to third aspects, as described in the fourth aspect, the first predetermined frequency may be equal to the second predetermined frequency.
According to the thus configured optical scanning device, it is possible to synchronize the vibration of the first comb-shaped electrode portion of the reflecting portion with the vibration of the second comb-shaped electrode portion. Thereby, it becomes possible to vibrate the 2nd comb-tooth-shaped electrode part so that the 2nd comb-tooth-shaped electrode part exists in the advancing direction of the 1st comb-tooth-shaped electrode part of a reflection part. For this reason, since the reflection part vibrates with a larger angular amplitude, electrostatic attraction can be generated in a dominant direction. Therefore, the angular amplitude of the vibration of the reflecting portion can be further increased, and the angle (scanning angle) at which the optical scanning device scans the light beam can be further increased.

  Further, in the optical scanning device according to claim 1 or 2, as described in claim 5, the second swing support portion is a second elastically deformable second member connected to the second comb-shaped electrode portion. An elastic connecting portion is provided, and the second comb-like electrode portion is swingably supported using the second elastic connecting portion as a second rotation axis, and the vibration means extends from the second elastic connecting portion into a comb-like shape. The 3rd comb-tooth electrode part formed and the 4th comb tooth formed in the comb-tooth shape which can mesh with the 3rd comb-tooth electrode part, and installed in the position which can mesh with the 3rd comb-tooth electrode part And a voltage applying means for generating an electrostatic attractive force between the electrode portions by applying a voltage between the third comb-tooth electrode portion and the fourth comb-tooth electrode portion. It is good to.

  In the thus configured optical scanning device, the voltage applying means applies a voltage between the third comb-shaped electrode portion and the fourth comb-shaped electrode portion, thereby generating an electrostatic attractive force between both electrode portions. Due to this electrostatic attraction, the third comb-like electrode portion vibrates with the second elastic coupling portion as the second rotation axis. Since the second comb-like electrode portion is connected to the second elastic connecting portion, the second comb-like electrode portion is connected to the second elastic connecting portion in synchronization with the third comb-like electrode portion. Vibrates as two rotation axes.

  According to the optical scanning device configured as described above, unlike the optical scanning device according to the third aspect, it is not necessary to provide a piezoelectric element in order to configure the vibrating means, and the same material as that of the reflecting portion can be used. . Therefore, the manufacturing process can be simplified as compared with the optical scanning device according to the third aspect.

  By the way, the vibration of the reflection part has a resonance frequency determined by the moment of inertia of the reflection part and the spring constant of the first elastic coupling part, and is between the first comb-like electrode part and the second comb-like electrode part. By applying the voltage in synchronization with the resonance frequency, the reflection portion can be resonantly oscillated. Similarly, the vibration of the second comb-shaped electrode portion also has a resonance frequency determined by the moment of inertia of the second comb-shaped electrode portion and the third comb-shaped electrode portion and the spring constant of the second elastic coupling portion, By applying a voltage between the third comb-like electrode portion and the fourth comb-like electrode portion in synchronization with this resonance frequency, the second comb-like electrode portion can be caused to resonate and vibrate.

  Here, the resonance frequency is expressed by the equation (1) where the moment of inertia is J and the spring constant kp.

したがって、請求項５に記載の光走査装置では、請求項６に記載のように、第１弾性連結部のバネ定数と反射部の慣性モーメントとの比は、第２弾性連結部のバネ定数と第２櫛歯状電極部および第３櫛歯状電極部の慣性モーメントとの比に等しいようにするとよい。

Therefore, in the optical scanning device according to claim 5, as described in claim 6, the ratio between the spring constant of the first elastic connecting portion and the moment of inertia of the reflecting portion is equal to the spring constant of the second elastic connecting portion. It is good to make it equal to ratio with the moment of inertia of the 2nd comb-tooth shaped electrode part and the 3rd comb-tooth shaped electrode part.

  In the optical scanning device configured as described above, the first predetermined frequency can be made equal to the second predetermined frequency when the reflection portion and the second comb-shaped electrode portion are caused to resonate and vibrate. Therefore, the same effect as that of the optical scanning device according to the fourth aspect can be obtained.

  In the optical scanning device according to any one of claims 1 to 6, as described in claim 7, the phase of the vibration of the first comb-shaped electrode portion is the vibration of the second comb-shaped electrode portion. It is preferable that the phase is opposite to the above phase.

  According to the optical scanning device configured in this way, the direction in which the first comb-shaped electrode portion is inclined by vibration and the direction in which the second comb-shaped electrode portion is inclined by vibration are reversed. It becomes possible to vibrate the second comb-shaped electrode portion so that the second comb-shaped electrode portion exists in the traveling direction of the first comb-shaped electrode portion of the reflecting portion. Therefore, the same effect as that of the optical scanning device according to the fourth aspect can be obtained.

  Further, in the optical scanning device according to any one of claims 1 to 7, as described in claim 8, the second rotation axis is a reflecting surface in a state where the phase angle of vibration of the reflecting portion is 0 °. It is good to arrange | position in the position which remove | deviated from the plane containing.

  In the optical scanning device configured as described above, there is a positional relationship in which there is a step between the first comb-shaped electrode portion and the second comb-shaped electrode portion in a state where the phase angle of vibration of the reflecting portion is 0 °. Become. For this reason, when the vibration is performed from the state where the phase angle of the vibration of the reflecting portion is 0 °, the second comb-shaped electrode portion exists in the traveling direction of the first comb-shaped electrode portion of the reflecting portion. Thereby, the direction of the electrostatic attraction generated between the first comb-shaped electrode portion and the second comb-shaped electrode portion becomes an effective direction for rotating the reflecting portion. That is, in order for the reflecting portion to vibrate with a larger angular amplitude than when the second rotation axis is located on a plane including the reflecting surface in a state where the phase angle of vibration of the reflecting portion is 0 °. The electrostatic attractive force can be generated in a dominant direction, and the angular amplitude of the vibration of the reflecting portion can be further increased.

(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a plan view showing a configuration of an optical scanning device 1 according to a first embodiment to which the present invention is applied, and FIG. 2 is a comb electrode portions 21 and 22 for explaining vibrations of the comb electrode portions 21 and 22. FIG.

  The optical scanning device 1 is manufactured by processing, for example, an SOI (Silicon On Insulator) wafer by a semiconductor process, and includes a light beam reflecting unit 2 that reflects a light beam and a support unit that supports the light beam reflecting unit 2. 3 and a driving unit 4 that applies a rotational driving force to the light beam reflecting unit 2.

  The light beam reflecting portion 2 includes a rectangular main body portion 11 having a mirror surface of an aluminum thin film formed on the surface, an elastically deformable elastic connecting portion 12 that connects the upper side 11a of the main body portion 11 and the support portion 3, and a main body. An elastically deformable elastic connecting portion 13 that connects the lower side 11b of the portion 11 and the support portion 3, a comb electrode portion 14 that is provided on the left side 11c of the main body portion 11 and is formed in a comb shape, and the main body portion 11 It is comprised from the comb-tooth electrode part 15 provided in the right side 11d of this, and was formed in the comb-tooth shape.

Among these, the elastic connection part 12 and the elastic connection part 13 are arrange | positioned on the same straight line, and become the rotating shaft KJ1 of the light beam reflection part 2. FIG.
Further, the comb teeth constituting the comb electrode portions 14 and 15 extend in a direction orthogonal to the rotation axis KJ1.

  Next, the support part 3 includes an upper support part 3a connected to the end part of the elastic connection part 12 on the side not connected to the upper side 11a, and an end part of the elastic connection part 13 on the side not connected to the lower side 11b. It is comprised from the lower side support part 3b connected.

  Further, the drive unit 4 is formed in a comb-teeth shape that is engaged with the comb-teeth electrode portion 14 with a predetermined interval and a comb-teeth electrode portion 21 that is engaged with the comb-teeth electrode portion 15 with a predetermined interval. The comb-shaped electrode part 22, the upper support part 3a and the lower support part 3b are connected to each other and the elastically deformable elastic connecting part 23 for supporting the comb-shaped electrode part 21 is provided. The upper support part 3a and the lower support part 3b and an elastically deformable elastic connecting part 24 for supporting the comb electrode part 22, a comb driving part 25 for driving the comb electrode part 21, and a comb driving for driving the comb electrode part 22 Part 26.

  As shown in FIG. 2A, the comb tooth drive unit 25 is provided on one surface P1 of the two surfaces P1 and P2 which are not opposed to the comb electrode portion 14 in the comb electrode portion 21. The piezoelectric element part 31 and the piezoelectric element part 32 provided on the other surface P2 are configured. The piezoelectric element portions 31 and 32 are configured by laminating electrodes 41 and 46, piezoelectric elements 42 and 47 (for example, PZT) and electrodes 43 and 48 in order from the surfaces P1 and P2, respectively.

  Similarly to the comb drive unit 25, the comb drive unit 26 is provided on one surface P3 of the two surfaces P3 and P4 which are not opposed to the comb electrode unit 15 in the comb electrode unit 22. The piezoelectric element portion 33 and the piezoelectric element portion 34 provided on the other surface P2 are configured. The piezoelectric element portions 33 and 34 are configured by laminating electrodes 51 and 56, piezoelectric elements 52 and 57 (for example, PZT) and electrodes 53 and 58 in the order close to the surfaces P3 and P4.

  Thus, when a voltage is applied between the electrodes 41 and 51 of the piezoelectric element portions 31 and 33 and the electrodes 43 and 53, respectively, as shown in FIG. 2 (b), the piezoelectric element 42, 52 is compressed (see arrow C1 in the figure), and the side where the piezoelectric element parts 31, 33 are disposed, That is, it is deformed so as to be inclined toward the planes P1 and P3 (see arrow R1 in the figure). On the other hand, when a voltage is applied between the electrodes 46 and 56 of the piezoelectric element portions 32 and 34 and the electrodes 48 and 58, respectively, as shown in FIG. 2 (c), the piezoelectric elements 47 and 57 (represented by the comb electrode portion 21) are compressed (see the arrow C2 in the figure), and the side where the piezoelectric element portions 32 and 34 are arranged, that is, It is deformed so as to incline toward the surfaces P2 and P4 (see arrow R2 in the figure).

Next, the electrical configuration of the optical scanning device 1 will be described. FIG. 3 is a block diagram showing an electrical configuration of the optical scanning device 1.
As shown in FIG. 3, the optical scanning apparatus 1 includes a reflection unit drive signal generation circuit 61 that outputs a pulse voltage as a drive signal for rotationally driving the light beam reflection unit 2, and a reflection unit drive signal generation circuit 61. A reflection part drive signal amplifier circuit 62 that amplifies the output drive signal and applies it to the comb electrode parts 21 and 22, and a comb that outputs a pulse voltage as a drive signal for driving the comb electrode parts 21 and 22 The tooth drive signal generating circuit 63, the comb drive signal amplifying circuit 64 for amplifying the drive signal output from the comb drive signal generating circuit 63 and applying it to the piezoelectric element units 31 to 34, and the light source of the light beam. The semiconductor laser 65 includes a control circuit 66 that controls the semiconductor laser 65 and controls the reflection portion drive signal generation circuit 61 and the comb drive signal amplification circuit 64.

Next, the operation of the optical scanning device 1 will be described.
When the reflection part drive signal generation circuit 61 outputs a drive signal based on the control by the control circuit 66, the voltage value of this drive signal is amplified by the reflection part drive signal amplification circuit 62 and applied to the comb electrode parts 21 and 22. The Thereby, a pulse voltage is applied between the comb-tooth electrode portions 21 and 22 and the comb-tooth electrode portions 14 and 15 to generate an electrostatic attractive force that periodically changes, and the elastic coupling portions 12 and 13 are elastically deformed. By being twisted, the main body 11 reciprocally vibrates about the elastic connecting portions 12 and 13 as the rotation axis KJ1.

  Here, the reflection part drive signal generation circuit 61 is twice the resonance frequency of the torsional vibrator (hereinafter also referred to as reflection part resonance frequency) determined by the moment of inertia of the main body part 11 and the spring constant of the elastic coupling parts 12 and 13. The drive signal of the frequency of is output. Thereby, the vibration system composed of the main body 11 and the elastic coupling parts 12 and 13 resonates, and the main body 11 reciprocates at the reflection part resonance frequency.

  When the main body 11 is irradiated with a light beam from the semiconductor laser 65 in this state, the light beam is emitted by being reflected by the mirror surface of the main body 11, and with the reciprocal vibration of the main body 11, Scanning is performed in a direction corresponding to the rotation angle of the main body 11.

  Further, the comb drive signal amplification circuit 64 outputs a drive signal so as to alternately apply a voltage between the piezoelectric element units 31 and 34 and the piezoelectric element units 32 and 33 at a frequency twice the resonance frequency of the reflection unit. As a result, the comb electrode portions 21 and 22 reciprocate at the reflection portion resonance frequency.

  Hereinafter, a method of applying a voltage to the piezoelectric element portions 31 to 34 will be described with reference to FIG. FIG. 4 is a cross-sectional view of the main body 11 and the comb electrode parts 21 and 22 for explaining the vibration of the main body part 11 and the comb electrode parts 21 and 22.

  When the posture of the main body 11 is expressed by a phase angle, the main body 11 is in a horizontal state (see FIG. 4A) 0 °, and is tilted to the left (see FIG. 4B) 90 °. Again, the horizontal state (see FIG. 4A) is 180 °, and the state inclined to the right (see FIG. 4C) is 270 °.

  First, when the phase angle is 0 ° or 180 °, no voltage is applied to the piezoelectric element portions 31 to 34. Accordingly, as shown in FIG. 4A, the comb electrode portions 21 and 22 are not deformed, and the comb electrode portions 14 and 15 and the comb electrode portions 21 and 22 of the main body portion 11 in the horizontal state are Opposite.

  Further, when the phase angle is 90 °, voltage is applied to the piezoelectric element portions 32 and 33, and voltage is not applied to the piezoelectric element portions 31 and 34. As a result, as shown in FIG. 4B, the comb electrode portions 21 and 22 are deformed toward the side where the piezoelectric element portions 32 and 33 are installed, and the main body portion 11 is in a state of being maximally inclined to the left. The comb electrode parts 14 and 15 and the comb electrode parts 21 and 22 face each other.

  Further, when the phase angle is 270 °, a voltage is applied to the piezoelectric element portions 31 and 34, and a voltage is not applied to the piezoelectric element portions 32 and 33. Thereby, as shown in FIG.4 (c), the comb-tooth electrode parts 21 and 22 deform | transform toward the side in which the piezoelectric element parts 31 and 34 are installed, and the main-body part 11 in the state inclined to the right at the maximum. The comb electrode parts 14 and 15 and the comb electrode parts 21 and 22 face each other.

  In the optical scanning device 1 configured as described above, the positions of the comb-tooth electrode portions 21 and 22 can be changed by causing the comb-tooth drive portions 25 and 26 to vibrate the comb-tooth electrode portions 21 and 22. Accordingly, the comb teeth so that the comb electrode portions 14 and 15 and the comb electrode portions 21 and 22 face each other in accordance with the change in position of the comb electrode portions 14 and 15 due to the vibration of the comb electrode portions 14 and 15. It becomes possible to change the positions of the electrode portions 21 and 22. For this reason, when the main body part 11 is vibrated, the range of angular amplitudes where the comb electrode parts 14 and 15 and the comb electrode parts 21 and 22 face each other, that is, the comb electrode parts 14 and 15 and the comb electrode part. The range of the angular amplitude that can generate electrostatic attraction between 21 and 22 can be increased compared to the case where the positions of the comb electrode portions 21 and 22 are not changed. . Thereby, the angular amplitude of the vibration of the main body 11 can be increased, and the angle (scanning angle) at which the optical scanning device 1 scans the light beam can be increased.

  In addition, the comb drive units 25 and 26 vibrate the comb electrode units 21 and 22 with respect to the support unit 3 that supports the comb electrode units 21 and 22. That is, it is not necessary to vibrate the support part 3 in order to vibrate the comb electrode parts 21 and 22. For this reason, it is not necessary to provide a means for vibrating the comb electrode portions 21 and 22 outside the support portion 3. Thereby, the increase in the dimension of the optical scanning device 1 whole can be suppressed.

  Further, it is not necessary to vibrate the comb electrode portions 14 and 15 and the comb electrode portions 21 and 22 in order to vibrate the main body portion 11. That is, only the main body 11 needs to be vibrated in order to vibrate the main body 11. For this reason, in order to vibrate the main-body part 11, the increase in the mass of what is made to vibrate can be suppressed to the minimum, and the angular amplitude of the vibration of the main-body part 11 can be efficiently increased.

  Further, the comb electrode portions 14 and 15 and the comb electrode portions 21 and 22 are provided on both sides of the main body portion 11 with the rotation axis KJ1 interposed therebetween. For this reason, in order to vibrate the main body part 11, electrostatic attraction can be generated on both sides of the main body part 11 with the rotation axis KJ1 interposed therebetween. Thereby, since the force for vibrating the main body part 11 can be distributed to both sides of the main body part 11, compared with the case where electrostatic attraction is generated only on one side of the main body part 11 with the rotation axis KJ1 interposed therebetween. The voltage applied between the comb electrode portions 14 and 15 and the comb electrode portions 21 and 22 can be reduced. Furthermore, since it is possible to apply electrostatic attraction evenly to both sides of the main body 11, the main body 11 can be vibrated more stably than when electrostatic attraction is applied only to one side of the main body 11. Can do.

  Further, since the comb electrode parts 21 and 22 are vibrated by expansion and contraction of the piezoelectric elements 42, 47, 52 and 57 by the comb tooth drive parts 25 and 26, the comb electrode parts 21 and 22 are independent of the vibration of the main body part 11. Can be vibrated.

  The vibration frequency of the main body 11 is equal to the vibration frequency of the comb electrode portions 21 and 22. Therefore, the vibrations of the comb electrode parts 14 and 15 of the main body 11 and the vibrations of the comb electrode parts 21 and 22 can be synchronized. Further, when the main body portion 11 is tilted to the maximum left, the comb electrode portions 21 and 22 are tilted to the maximum right (see FIG. 4B), and when the main body portion 11 is tilted to the maximum maximum right. The phase of the vibration of the comb electrode parts 14 and 15 of the main body 11 is such that the comb electrode parts 21 and 22 are inclined to the left (see FIG. 4C). The phase is opposite to the phase of the vibrations 21 and 22. Thereby, the comb electrode parts 21 and 22 can be vibrated so that the comb electrode parts 21 and 22 exist in the traveling direction of the comb electrode parts 14 and 15 of the main body part 11. For this reason, since the main-body part 11 vibrates with a larger angular amplitude, an electrostatic attractive force can be generated in a dominant direction. Therefore, the angular amplitude of vibration of the main body 11 can be further increased, and the angle (scanning angle) at which the optical scanning device 1 scans the light beam can be further increased.

  In the embodiment described above, the main body portion 11 is the reflection portion in the present invention, the elastic connection portions 12 and 13 are the first elastic connection portion in the present invention, and the rotation axis KJ1 is the first rotation shaft and the elastic connection portion 12 in the present invention. 13 and the support part 3 are the first swing support part in the present invention, the comb electrode parts 14 and 15 are the first comb electrode parts, the comb electrode parts 21 and 22 and the elastic connection parts 23 and 24 in the present invention. In the present invention, the second comb-shaped electrode section and the support section 3 are the second swing support section, the comb drive signal generating circuit 63, the comb drive signal amplification circuit 64, and the comb drive sections 25 and 26 in the present invention. In the present invention, the vibrating means, electrodes 41, 43, 46, 48, 51, 53, 56, 58 are the expansion / contraction means in the present invention, and the reflection part resonance frequencies are the first predetermined frequency and the second predetermined frequency in the present invention.

(Second Embodiment)
A second embodiment of the present invention will be described below with reference to the drawings. In the second embodiment, only parts different from the first embodiment will be described.

  The optical scanning device 1 of the second embodiment is the same as the first embodiment except that the configuration of the drive unit 4 and the electrical configuration of the optical scanning device 1 are changed. FIG. 5 is a plan view showing the configuration of the optical scanning device 1 of the second embodiment to which the present invention is applied.

  As shown in FIG. 5, the driving unit 4 meshes with the comb electrode part 71 formed in a comb-like shape that meshes with the comb electrode part 14 with a certain interval, and with the comb electrode part 15 with a certain interval. An elastically deformable elastic connecting portion 73 that connects the comb-shaped electrode portion 72, the upper support portion 3a and the lower support portion 3b, and supports the comb-tooth electrode portion 71, and an upper support portion. 3a and the lower support portion 3b are connected to each other, and an elastically deformable elastic connecting portion 74 that supports the comb-shaped electrode portion 72, and a comb-shaped electrode portion 75 that is provided in the elastic connecting portion 73 and is formed in a comb shape. A comb-teeth electrode portion 76 provided in the elastic connecting portion 74 and formed in a comb-teeth shape; a comb-teeth electrode portion 77 formed in a comb-teeth shape that meshes with the comb-teeth electrode portion 75 at a predetermined interval; A comb-tooth electrode portion 78 formed in a comb-tooth shape that meshes with the comb-tooth electrode portion 76 at a predetermined interval. It consists of. The comb-teeth electrode part 71, the elastic coupling part 73, and the comb-teeth electrode part 75 are combined into a movable comb tooth 70a, and the comb-teeth electrode part 72, the elastic coupling part 74, and the comb-teeth electrode part 76 are grouped into a movable comb tooth. 70b.

Next, the electrical configuration of the optical scanning device 1 will be described. FIG. 6 is a block diagram showing an electrical configuration of the optical scanning device 1.
As shown in FIG. 6, the optical scanning device 1 includes a reflection part drive signal generation circuit 81 that outputs a pulse voltage as a drive signal for rotationally driving the light beam reflection part 2 and the comb electrode parts 71 and 72; A reflection part drive signal amplification circuit 82 that amplifies the drive signal output from the reflection part drive signal generation circuit 81 and applies the amplified drive signal to the comb electrode parts 71, 72, 75, and 76, and a semiconductor laser 83 that serves as a light beam emission source. And a control circuit 84 for controlling the semiconductor laser 83 and for controlling the reflection part drive signal generation circuit 81.

  Next, the operation of the optical scanning device 1 will be described. FIG. 7 is a cross-sectional view of the main body 11 and the movable comb teeth 70a and 70b for explaining the vibration of the main body 11 and the movable comb teeth 70a and 70b.

  When the reflection portion drive signal generation circuit 81 outputs a drive signal based on the control by the control circuit 84, the reflection portion drive signal amplification circuit 82 amplifies the voltage value of this drive signal and applies it to the comb electrode portions 71 and 72. The Thereby, a pulse voltage is applied between the comb-tooth electrode portions 71 and 72 and the comb-tooth electrode portions 14 and 15 to generate an electrostatic attractive force that periodically changes, and the elastic coupling portions 12 and 13 are elastically deformed. As a result, the main body 11 reciprocally vibrates about the elastic connecting portions 12 and 13 as the rotation axis KJ1.

  Here, the reflection part drive signal generation circuit 81 drives at a frequency twice the resonance frequency (reflection part resonance frequency) of the torsional vibrator determined by the moment of inertia of the main body part 11 and the spring constant of the elastic coupling parts 12 and 13. Output a signal. Thereby, the vibration system composed of the main body 11 and the elastic coupling parts 12 and 13 resonates, and the main body 11 reciprocates at the reflection part resonance frequency.

  When the main body 11 is irradiated with a light beam from the semiconductor laser 83 in this state, the light beam is emitted by being reflected by the mirror surface of the main body 11, and along with the reciprocal vibration of the main body 11, Scanning is performed in a direction corresponding to the rotation angle of the main body 11.

  Further, the voltage value of the drive signal is amplified by the reflection portion drive signal amplification circuit 82 and applied to the comb electrode portions 75 and 76, whereby the comb electrode portions 75 and 76, the comb electrode portions 77 and 78, and During this period, a pulse voltage is applied to generate an electrostatic attractive force that changes periodically. As a result, the elastic connecting portions 73 and 74 are elastically deformed and twisted, and the movable comb teeth 70a and 70b reciprocally vibrate using the elastic connecting portions 73 and 74 as the rotation axes KJ2 and KJ3, respectively.

  Here, the resonance frequency of the torsional vibrator (hereinafter also referred to as a comb tooth resonance frequency) determined by the moment of inertia of the comb electrode parts 71, 72, 75, 76 and the spring constant of the elastic coupling parts 73, 74 is the reflection part. The moment of inertia of the comb electrode portions 71, 72, 75, and 76 and the spring constant of the elastic coupling portions 73 and 74 are set so as to be equal to the resonance frequency. As a result, the vibration system composed of the comb electrode portions 71, 72, 75, 76 and the elastic coupling portions 73, 74 resonates, and the movable comb teeth 70a, 70b have a comb tooth resonance frequency equal to the reflection portion resonance frequency. Vibrates back and forth.

  Therefore, the movable comb teeth 70a and 70b are in a horizontal state when the main body portion 11 is in a horizontal state (see FIG. 7A), and the movable comb teeth 70a are in a state in which the main body portion 11 is tilted to the left to the maximum. 70b is tilted to the right (see FIG. 7B), and when the main body 11 is tilted to the right, the movable comb teeth 70a, 70b are tilted to the left (see FIG. 7). 7 (c)). Thereby, while the main-body part 11 is vibrating, the comb-tooth electrode parts 14 and 15 and the comb-tooth electrode parts 71 and 72 are always made to oppose.

  In the optical scanning device 1 configured as described above, it is not necessary to provide a piezoelectric element to vibrate the comb electrode portions 71 and 72, and the same material as that of the main body portion 11 can be used. Therefore, the manufacturing process can be simplified as compared with the optical scanning device 1 of the first embodiment.

  In addition, the resonance frequency (comb tooth resonance frequency) of the torsional vibrator determined by the moment of inertia of the comb electrode portions 71, 72, 75, 76 and the spring constant of the elastic coupling portions 73, 74 is the moment of inertia of the main body portion 11. And the moment of inertia of the comb-tooth electrode portions 71, 72, 75, 76 and the elastic connecting portion 73, so as to be equal to the resonance frequency (reflecting portion resonance frequency) of the torsional vibrator determined by the spring constant of the elastic connecting portions 12, 13. A spring constant of 74 is set. For this reason, the vibration frequency of the main body 11 is equal to the vibration frequency of the comb electrode portions 71 and 72. Therefore, the vibrations of the comb electrode portions 14 and 15 of the main body 11 and the vibrations of the comb electrode portions 71 and 72 can be synchronized. Thus, the comb electrode portions 71 and 72 can be vibrated so that the comb electrode portions 71 and 72 exist in the traveling direction of the comb electrode portions 14 and 15 of the main body portion 11. For this reason, since the main-body part 11 vibrates with a larger angular amplitude, an electrostatic attractive force can be generated in a dominant direction. Further, frictional resistance and viscous pressure resistance due to air generated between the comb electrode portions 17 and 18 and the comb electrode portions 71 and 72 can also be reduced. Therefore, the angular amplitude of vibration of the main body 11 can be increased, and the angle (scanning angle) at which the optical scanning device 1 scans the light beam can be increased.

  In the embodiment described above, the comb electrode portions 71 and 72 and the elastic connecting portions 73 and 74 are the second comb electrode portions according to the present invention, and the support portion 3 is the second swing support portion according to the present invention, the rotation axis KJ2. , KJ3 is the second rotation shaft in the present invention, elastic connection portions 73 and 74 are the second elastic connection portions in the present invention, and the comb electrode portions 75 and 76 are the third comb electrode portions and the comb electrode portions in the present invention. Reference numerals 77 and 78 denote the fourth comb-tooth electrode portion, the reflection portion drive signal generation circuit 81 and the reflection portion drive signal amplification circuit 82 in the present invention, which are voltage application means in the present invention.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken.
For example, in the second embodiment, as shown in FIG. 7A, when the main body 11 is in a horizontal state (that is, in a state where the phase angle is 0 °), on the plane JP including the main body 11. Fig. 1 shows the one where the rotation axes KJ1, KJ2, and KJ3 are arranged. However, as shown in FIGS. 8A and 8B, the rotation axes KJ2 and KJ3 may be arranged at positions deviating from the plane JP. When the rotation shafts KJ1, KJ2, and KJ3 are arranged in this way, as shown in FIG. 8C, the comb-like electrode portions 14 and 15 of the main-body portion 11 and the comb-tooth electrodes when the main-body portion 11 is horizontal. There is a positional relationship in which there is a step DF between the portions 71 and 72. For this reason, when the vibration is performed from the state where the phase angle of the vibration of the main body 11 is 0 °, the comb electrode portions 71 and 72 exist in the traveling direction of the comb electrode portions 14 and 15 of the main body portion 11. . Thereby, the direction of the electrostatic attractive force generated between the comb electrode portions 14 and 15 and the comb electrode portions 71 and 72 becomes an effective direction for rotating the main body portion 11. That is, the main body 11 has a larger angular amplitude than the case where the rotation axes KJ2 and KJ3 are positioned on a plane including the main body 11 in a state where the phase angle of vibration of the main body 11 is 0 °. An electrostatic attractive force can be generated in a dominant direction for vibration, and the angular amplitude of vibration of the main body 11 can be further increased.

  Moreover, in the said embodiment, although the thing in which the comb-tooth electrode part was provided in both the left side 11c side and the right side 11d side of the main-body part 11 was shown, a comb tooth is provided in either the left side 11c side or the right side 11d side. An electrode part may be provided.

It is a top view which shows the structure of the optical scanning device 1 of 1st Embodiment. It is sectional drawing of the comb-tooth electrode part 21 and 22 of 1st Embodiment. 1 is a block diagram illustrating an electrical configuration of an optical scanning device 1 according to a first embodiment. It is sectional drawing of the main-body part 11 and the comb-tooth electrode parts 21 and 22 of 1st Embodiment. It is a top view which shows the structure of the optical scanning device 1 of 2nd Embodiment. It is a block diagram which shows the electric constitution of the optical scanning device 1 of 2nd Embodiment. It is sectional drawing of the main-body part 11 and movable comb-tooth 70a, 70b of 2nd Embodiment. It is sectional drawing of the main-body part 11 and movable comb-tooth 70a, 70b of another embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical scanning device, 2 ... Light beam reflection part, 3 ... Support part, 4 ... Drive part, 11 ... Main-body part, 12, 13, 23, 24, 73, 74 ... Elastic connection part, 14, 15, 21, 22, 71, 72, 75, 76, 77, 78 ... comb-teeth electrode part, 25, 26 ... comb-teeth drive part, 31, 32, 33, 34 ... piezoelectric element part, 41, 43, 46, 48, 51, 53, 56, 58 ... electrodes, 42, 47, 52, 57 ... piezoelectric elements, 61, 81 ... reflection part drive signal generation circuit, 62, 82 ... reflection part drive signal amplification circuit, 63 ... comb tooth drive signal generation circuit, 64 ... comb tooth drive signal amplifier circuit, 65, 83 ... semiconductor laser, 66, 84 ... control circuit, 70a, 70b ... movable comb teeth, KJ1, KJ2, KJ3 ... rotating shaft

Claims (8)

A reflecting portion having a reflecting surface for reflecting the light beam;
A first swing support portion that has an elastically deformable first elastic connection portion that is connected to the reflection portion, and that supports the reflection portion in a swingable manner using the first elastic connection portion as a first rotation axis;
A first comb-like electrode portion extending from the reflecting portion and formed in a comb-teeth shape;
A second comb-like electrode portion that is formed in a comb-like shape that can mesh with the first comb-like electrode portion and is disposed at a position that can mesh with the first comb-like electrode portion;
By applying a voltage between the first comb-shaped electrode portion and the second comb-shaped electrode portion, the reflecting portion is vibrated at a first predetermined frequency by electrostatic attraction generated between the two electrode portions. An optical scanning device configured as described above,
A second swing support portion that swingably supports the second comb-shaped electrode portion around a second rotation shaft having the same axial direction as the first rotation shaft ;
And an oscillating means for oscillating the second comb-like electrode portion with respect to the second oscillating support portion at a second predetermined frequency. 2. The optical scanning device according to claim 1, wherein the first comb-shaped electrode portion and the second comb-shaped electrode portion are provided on both sides of the reflecting portion with the first rotation axis interposed therebetween. The vibration means includes
A piezoelectric element fixed to two surfaces of the second comb-shaped electrode portion that is not opposed to the first comb-shaped electrode portion;
3. The optical scanning device according to claim 1, wherein the piezoelectric element is configured by expansion / contraction means that expands / contracts the piezoelectric element along a direction in which the second comb-shaped electrode portion extends. The optical scanning device according to any one of claims 1 to 3, wherein the first predetermined frequency is equal to the second predetermined frequency. The second swing support part is
A second elastic coupling part capable of linked elastically deformed to the second comb-shaped electrode portions, swingable said second comb-shaped electrode portions of the second elastic connecting portions as said second rotary shaft To support
The vibration means includes
A third comb-like electrode portion extending from the second elastic coupling portion and formed in a comb-teeth shape;
A fourth comb-shaped electrode portion formed in a comb-tooth shape engageable with the third comb-shaped electrode portion, and disposed at a position engageable with the third comb-shaped electrode portion;
And a voltage applying means for generating an electrostatic attractive force between the electrode parts by applying a voltage between the third comb-like electrode part and the fourth comb-like electrode part. The optical scanning device according to claim 1 or 2. The ratio between the spring constant of the first elastic connecting portion and the moment of inertia of the reflecting portion is the spring constant of the second elastic connecting portion and the inertia of the second comb-like electrode portion and the third comb-like electrode portion. The optical scanning device according to claim 5, wherein the optical scanning device is equal to a ratio with a moment. 7. The phase of vibration of the first comb-like electrode part is opposite to the phase of vibration of the second comb-like electrode part. 7. Optical scanning device. The second rotation axis is
8. The optical scanning device according to claim 1, wherein the optical scanning device is disposed at a position deviating from a plane including the reflecting surface in a state where the phase angle of vibration of the reflecting portion is 0 °. .

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