JP2009258210A - Optical reflection element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical reflection element used in a laser scan unit or the like such as a laser printer and an electrophotographic apparatus for attaining a compact laser scan unit. <P>SOLUTION: The optical reflection element includes: a supporting body 1; a first supporting part 2 supported by the supporting body 1; a tuning fork oscillator 6 composed of a first arm 3 and a second arm 4 which are supported by the other end of the first supporting part 2; a second supporting part 11 supported at the oscillation center 9 of the tuning fork oscillator 6; and a mirror part 12 supported by the other end of the second supporting part 11; wherein the second supporting part 11 is formed into a meander shape and a monitoring piezoelectric element 8 is provided at a part of the second supporting part 11 for controlling oscillation. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical reflection element used in a laser scan unit or the like.

Conventionally, as a laser scanning unit that sweeps light emitted from a laser used in a laser printer or the like, a polygon mirror provided with a mirror on the side surface of a polygonal rotating body has been used. A laser beam was swept onto the scanning surface of the body drum (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 11-281908

  With such widespread use of color laser printers and miniaturization of printers, miniaturization of optical reflecting elements used in laser scan units has become a proposition. However, in a laser scanning unit using a polygon mirror, in addition to downsizing the polygon mirror, a separate drive device for driving the polygon mirror is required, and thus downsizing is very difficult. It was.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve such problems and to realize an optical reflecting element that can reduce the size of a laser scan unit and can perform high-precision control.

  In order to achieve this object, the present invention provides an optical reflecting element supported by a support, a first support part having one end supported by the support, and the other end of the first support part. A tuning fork vibrator having a first arm and a second arm, a second support part supported at one end at the vibration center of the tuning fork vibrator, and supported at the other end of the second support part. The second support part has a meander shape, and a monitoring piezoelectric element for controlling vibration is provided on a part of the second support part.

  By adopting such a configuration, the bending impulse and the torsional vibration are combined, and the vibration state of the tuning fork vibrator is feedback-controlled using the monitoring piezoelectric element to control the vibration of the mirror portion, so that the light beam can be accurately obtained. A small optical reflecting element for sweeping can be realized.

(Embodiment 1)
Hereinafter, the configuration of the optical reflecting element according to Embodiment 1 of the present invention will be described with reference to the drawings.

  FIG. 1 is a plan view of the optical reflecting element according to the first embodiment, FIG. 2 is a cross-sectional view of the AA portion of FIG. 1, and FIG. 3 is a conceptual diagram for explaining the operation principle of the optical reflecting element.

  1 to 3, the optical reflecting element includes a tuning fork vibrator 6 including a first support portion 2, a first arm 3, a second arm 4, and a connecting portion 5, and the first support portion. One end of 2 is fixed to the support body 1, one end of the second support portion 11 is fixed to the vibration center 9 of the tuning fork vibrator 6, and light such as a laser beam is reflected to the other end of the second support portion 11. A configuration having a mirror portion 12 for this purpose is basically used. The shape of the second support portion 11 is a meander, and a monitoring piezoelectric element 8 for controlling the vibration of the tuning fork vibrator 6 is provided in a part of the cantilever constituting the meander shape.

  By using the second support portion 11 as a support portion having a meander shape, the second support portion 11 is likely to be twisted to cause repetitive rotational vibration of the mirror portion 12, thereby causing resonance of the optical reflecting element. The frequency can be reduced, and downsizing of the optical reflecting element can be realized.

  Further, the monitoring piezoelectric element 8 provided on a part of the second support portion 11 having a meander shape is twisted from the monitoring piezoelectric element 8 when the connecting portion 5 of the tuning fork vibrator 6 is twisted about the rotation shaft 14. The electric signal output according to the magnitude of the signal is extracted, the phase and voltage as the electric signal are detected, and the electric signal for driving is feedback-controlled according to the detected electric signal, so that the tuning fork vibrator 6 As a result, the repetitive rotational vibration of the mirror unit 12 can be controlled with high accuracy, and a predetermined vibration state can be corrected with respect to a change with time or a temperature change.

  In addition, as a substrate material constituting the optical reflecting element, it is preferable from the viewpoint of productivity that an elastic member having elasticity, mechanical strength, and high Young's modulus is configured as the base material 20. Quartz, glass or quartz is preferably used from the viewpoint of mechanical properties and availability. Further, by using silicon, titanium, stainless steel, Elinvar, or a brass alloy as the metal, an optical reflective element having excellent vibration characteristics and workability can be realized.

  A piezoelectric actuator 10 for causing flexural vibration is formed on at least one surface of the first arm 3 and the second arm 4 made of a base material 20 such as silicon. At this time, it is preferable from the viewpoint of productivity to simultaneously form the monitoring piezoelectric element 8. The piezoelectric actuator 10 and the monitoring piezoelectric element 8 are preferably thin film laminated piezoelectric actuators having a laminated structure of the first electrode layer 21, the piezoelectric layer 22 and the second electrode layer 23. As a result, the tuning fork vibrator 6 can be designed to be thin. Further, by making the thickness of the tuning fork vibrator 6 smaller than the width dimension of the first arm 3 and the second arm 4, a small optical reflecting element can be realized.

  The first electrode layer 21, the piezoelectric layer 22, and the second electrode layer 23 can be sequentially formed on the base material 20 on which the tuning fork vibrator 6 is formed by a thin film process such as a sputtering technique. . Therefore, it is preferable from the viewpoint of productivity that the piezoelectric actuator 10 and the monitoring piezoelectric element 8 are formed on the same surface of the tuning fork vibrator 6. The piezoelectric actuator 10 is more preferably formed on almost the entire surface of the tuning fork vibrator 6.

  The piezoelectric material used for the piezoelectric layer 22 is preferably a piezoelectric material having a high piezoelectric constant such as lead zirconate titanate (PZT).

  Further, the mirror part 12 can be efficiently designed by vibration design so that the resonance frequency of the tuning fork vibrator 6 and the resonance frequency of the torsional vibrator constituted by the mirror part 12 and the second support part 11 are substantially the same frequency. It is possible to realize an optical reflecting element that repeatedly rotates and vibrates.

  Furthermore, by making the widths of the first arm 3, the second arm 4 and the connecting portion 5 equal, it is possible to provide an optical reflecting element that suppresses unnecessary vibration modes, and the tuning fork vibrator 6 can be The optical reflection element having the same effect can be obtained by forming the letter shape. And the effect can be exhibited more by combining these.

  Further, by using the same material for the base material 20 of the first support part 2, the tuning fork vibrator 6, the second support part 11 and the mirror part 12, an optical reflection element having stable vibration characteristics and excellent productivity is realized. can do.

  Next, the 2nd support part 11 is demonstrated. By forming the second support portion 11 in a meander shape as shown in FIG. 1, it is possible to realize a small optical reflecting element. However, the meander-shaped axis center is the same as the rotation axis 14 of the mirror portion 12. By arranging them on the line, unnecessary vibrations such as shaking vibrations can be suppressed. Here, as shown in FIG. 1, in the second support portion 11 having a meander shape, the axis center is a portion that torsionally vibrates about the center portion of the meander shape when the second support portion 11 is twisted. FIG. 1 shows a central portion arranged on the same line of the rotating shaft 14.

  Further, by making the meander shape symmetrical with respect to the rotation shaft 14 or the axis center, an optical reflecting element that can suppress the occurrence of stable vibration and unnecessary vibration can be realized.

  Furthermore, by arranging the meander shape on the same plane as the surface direction of the tuning fork vibrator 6, an optical reflecting element with excellent productivity can be obtained. In this case, the shape of the complex meander-shaped second support portion 11 and the tuning fork vibrator 6 can be collectively produced in a plane on a plate-like substrate such as a silicon wafer by photolithography and etching.

  Next, the cross-sectional shape of the first support portion 2 is preferably circular. As a result, the vibration mode of torsional vibration is stabilized, unnecessary resonance can be suppressed, and an optical reflection element that is hardly affected by disturbance vibration can be realized.

  The mirror portion 12 can also be formed by mirror polishing the surface of the substrate 20, and more preferably, can be formed as a mirror film of a metal thin film of gold or aluminum having excellent light reflection characteristics. It is. The mirror film made of these metal thin films can be formed by a sputtering technique in the same manner as described above in the process of manufacturing the piezoelectric actuator 10.

  The optical reflecting element having such a configuration can be manufactured in a lump with high accuracy by applying a semiconductor process such as a thin film process or a photolithography technique on the base material 20 such as a silicon wafer. Therefore, it is possible to realize an optical reflecting element that is small in size, high in accuracy, and excellent in production efficiency.

  Further, by utilizing the torsional vibration of the torsional vibrator composed of the second support part 11 having a meander shape and the mirror part 12, the resonance frequency is reduced, and the vibration of the mirror part 12 can be achieved while having a small device structure. An optical reflection element that can increase the angle can be realized.

  Further, the bending vibration of the first arm 3 and the second arm 4 constituting the tuning fork vibrator 6 which is a vibration driving part, the second support part 11 having a meander shape, and the torsion formed by the mirror part 12. An optical reflecting element capable of designing a wide range of drive frequencies, deflection angles, etc. of the mirror portion 12 by improving the degree of freedom of design due to the configuration of the vibrator, and devising the respective dimensions and shapes. Can be realized.

  The lead electrodes of the first electrode layer 21 and the second electrode layer 23 of the piezoelectric actuator 10 formed on the first arm 3 and the second arm 4 are individually provided with lead lines (not shown). While forming, it is connected to the connection terminal 25. As a result, opposite electrical signals can be applied to each piezoelectric actuator 10.

  Next, the operation principle of the optical reflecting element having such a configuration will be described. FIG. 3 is a conceptual diagram for explaining the vibration state of the optical reflecting element according to the first embodiment. As shown in FIG. 1 to FIG. 2, by applying an alternating drive voltage between the first electrode layer 21 and the second electrode layer 23 constituting the piezoelectric actuator 10, Expansion and contraction occur, and deformation of the piezoelectric actuator 10 causes bending vibration in directions (arrow directions 7a and 7b) in which the phases of the first arm 3 and the second arm 4 are different by 180 degrees. At this time, the first arm 3 and the second arm 4 are applied by applying the opposite polarity of the drive signal applied to each piezoelectric actuator 10 formed on the first arm 3 and the second arm 4. It will bend and vibrate in the opposite direction.

  The vibration energy of the first arm 3 and the second arm 4 is propagated to the connecting portion 5 of the tuning fork vibrator 6. As a result, the tuning fork vibrator 6 repeats rotational vibration (torsional vibration) at a predetermined frequency with the vibration center 9 of the tuning fork vibrator 6 as a vibration axis. At this time, a monitoring piezoelectric element 8 for monitoring the vibration state of the tuning fork vibrator 6 is provided in a part of the second support portion 11 having a meander shape, and an electric signal of the monitoring piezoelectric element 8 is provided. By electrically driving and controlling the tuning fork vibrator 6 using the, the vibration of the tuning fork vibrator 6 can be controlled with high accuracy.

  Next, the vibration energy of the repetitive rotational vibration is transmitted to the second support portion 11 having a meander shape joined to the connecting portion 5, and the second support portion 11 and the mirror are centered on the rotation shaft 14. As a torsional vibrator composed of the portion 12, torsional vibration is caused. As a result, repetitive rotational vibration is generated in the mirror section 12 in the arrow direction 13 with the rotation shaft 14 as the axis. At this time, the direction of the repetitive rotational vibration of the tuning fork vibrator 6 and the direction of the repetitive rotational vibration of the torsional vibrator composed of the second support part 11 and the mirror part 12 vibrate in opposite directions that are 180 degrees different in phase. It becomes.

  By constructing a vibrator having such a vibration mode and inputting a light beam generated from a laser light source or an LED light source to the mirror part 12, a small optical reflection element capable of increasing the deflection angle of the mirror part 12 is realized. can do. By designing the vibration of these vibration parts, the reflection angle of the output light can be greatly changed, and an optical reflection element capable of sweeping input light such as a laser beam to a predetermined design value is realized. be able to.

  In this way, the vibration source is the tuning fork vibrator 6 having a high Q value, and the vibration state of the tuning fork vibrator 6 can be electrically feedback-controlled using the monitoring piezoelectric element 8, and this stable vibration energy is supplied to the second vibration vibration source. By supplying it as excitation energy for generating torsional vibration to the torsional vibrator comprising the support portion 11 and the mirror portion 12, stable repetitive rotational vibration can be generated in the mirror portion 12.

  Note that the optical reflecting element in the case where the piezoelectric actuator 10 is formed on one surface of the first arm 3 and the second arm 4 in order to cause repetitive rotational vibration of the tuning fork vibrator 6 has been described as an example. By forming the piezoelectric actuator 10 on only one of them, it is possible to realize the same operation of the optical reflecting element as described above. This utilizes the vibration characteristics of the tuning fork, and when one of the arms is excited, kinetic energy is transmitted to the other arm via the connecting portion 5 so that the other arm can be vibrated. It is an application of properties.

  Next, the configuration of the monitoring piezoelectric element 8 provided on the second support portion 11 will be described in detail with reference to the drawings. FIG. 4 is a conceptual diagram for explaining the configuration of the monitoring piezoelectric element 8, and its dimensional shape ratio is arbitrary and is different from FIG. 1. In FIG. 4, the position where the monitoring piezoelectric element 8 is provided is preferably provided in a part of the cantilever constituting the second support portion 11 so as to be orthogonal to the rotation shaft 14. In the case where there are a plurality of cantilevers orthogonal to the rotating shaft 14, the function can be exhibited by providing at least one of the cantilevers. Which cantilever is provided can be selected as appropriate. The reason why it is preferable to form the monitoring piezoelectric element 8 on one cantilever of the second support portion 11 orthogonal to the rotating shaft 14 is that the cantilever constituting the second support portion 11 is disposed at a position where it can bend and vibrate. By doing so, a large output can be obtained, and it becomes easy to configure a detection circuit having excellent noise characteristics.

  The second electrode layer 23 of the monitoring piezoelectric element 8 is connected to the wiring pattern 17 and then connected to the terminal electrode 25c.

  Further, the second electrode layer 23 of the piezoelectric actuator 10a is connected to the terminal electrode 25b after being connected to the wiring pattern 18, and the second electrode layer 23 of the piezoelectric actuator 10b is connected to the terminal electrode 25d after being connected to the wiring pattern 19. Connected.

  On the other hand, the first electrode layer 21 is a common electrode as a ground electrode and is connected to the terminal electrode 25a (this wiring pattern is not shown).

  At this time, the second electrode layer 23 of the monitoring piezoelectric element 8 only needs to have a width of at least 20 μm. By forming the monitoring piezoelectric element 8 having such an electrode pattern, feedback control is performed. A circuit can be configured and the vibration of the tuning fork vibrator 6 can be controlled.

  The piezoelectric layer 22 can also be formed as the monitoring piezoelectric element 8 independently.

  As an application of the optical reflecting element having the above-described configuration, a laser beam printer can be cited as an example. The photosensitive unit used in this laser beam printer, etc., sensitizes the laser beam by reflecting the laser beam and changing the direction of reflection of the laser, the photosensitive drum irradiated with the laser beam emitted from the laser. It consists of an optical reflection element that sweeps the scanning surface of the drum. The optical reflection element used in this photosensitive unit is a small laser beam printer by using the optical reflection element having the structure shown in FIGS. Can be realized.

  Next, a method for manufacturing the optical reflecting element in the first embodiment will be described.

  First, a silicon substrate 20 having a thickness of 0.3 mm is prepared, and a first electrode layer 21 made of a platinum electrode is formed thereon using a thin film process such as sputtering or vapor deposition. At this time, the thickness of the silicon substrate 20 may be thick. As a result, a silicon substrate 20 having a large wafer shape can be used, and since warpage and the like are small, a highly accurate optical reflecting element can be efficiently manufactured.

  Thereafter, a piezoelectric layer 22 is formed on the first electrode layer 21 by a sputtering method or the like using a piezoelectric material such as lead zirconate titanate (PZT). At this time, it is preferable to use an oxide dielectric containing Pb and Ti as the orientation control layer between the piezoelectric layer 22 and the first electrode layer 21, and it is more preferable to form an orientation control layer made of PLMT. . Thereby, the crystal orientation of the piezoelectric layer 22 is further improved, and the piezoelectric actuator 10 and the monitoring piezoelectric element 8 having excellent piezoelectric characteristics can be realized.

  Next, a second electrode layer 23 made of titanium / gold is formed on the piezoelectric layer 22. At this time, titanium under the gold electrode is formed in order to increase the adhesion with the piezoelectric layer 22 such as a PZT thin film, and a metal such as chromium can be used in addition to titanium.

  As a result, the piezoelectric actuator 10 having excellent adhesion with the piezoelectric layer 22 and having a strong diffusion strength with the gold electrode can be formed. At this time, the platinum electrode is 0.2 μm thick, the PZT thin film is 3.5 μm, the titanium electrode is 0.01 μm, and the gold electrode is 0.3 μm.

  Next, a patterned first electrode layer 21, piezoelectric layer 22 and second electrode layer 23 are formed by etching using a photolithographic technique. At this time, a predetermined electrode pattern was formed using an etchant composed of an iodine / potassium iodide mixed solution, ammonium hydroxide, and hydrogen peroxide mixed solution as an etchant for the second electrode layer 23.

Moreover, as an etching method used for the first electrode layer 21 and the piezoelectric layer 22, any one of a dry etching method and a wet etching method, or a combination of these methods can be used. For example, in the case of a dry etching method, a fluorocarbon-based etching gas or SF ₆ gas can be used. The piezoelectric thin film layer is subjected to wet etching using an etching solution made of a mixed solution of hydrofluoric acid, nitric acid, acetic acid and hydrogen peroxide, thereby forming a patterned piezoelectric layer 22. Thereafter, the patterned first electrode layer 21 is further formed by etching the lower electrode thin film layer by dry etching, whereby the piezoelectric actuator 10 and the monitoring piezoelectric element 8 as shown in FIG. Can be formed.

Next, unnecessary silicon is removed by isotropically dry-etching the silicon substrate 20 using XeF ₂ gas, and an optical reflecting element having a shape as shown in FIG. 1 can be formed. . At this time, by arranging the second support part 11 having the meander shape and the tuning fork vibrator 6 on the same surface, the etching process collectively processes the optical reflecting element into a predetermined size and shape with high accuracy. be able to. Thereby, even a complicated meander shape can be easily processed.

Further, when a silicon substrate or the like is etched with high accuracy by utilizing anisotropy by dry etching, SF ₆ gas that promotes etching and C ₄ F ₈ gas that suppresses etching are used to make it more linear. Etching is preferably performed. In the etching, a mixed gas using the gas can be used, or an etching method in which the gas is alternately switched to perform dry etching is possible, and these methods are matched to the dimensional shape and processing accuracy. It is possible to select and perform etching appropriately.

  By the manufacturing method as described above, it is possible to efficiently produce a small and highly accurate optical reflecting element collectively.

  Further, by the manufacturing process as described above, the length of the first and second arms 3 and 4; 1.0 mm, width; 0.3 mm, and the length of the first support portion 2; 0.2 mm, width; 0.1 mm, linear length of the second support portion 11; 0.4 mm (effective length including bending; 1.6 mm), width; 0.1 mm, mirror portion 12; 1.0 × 1.0 mm, When the piezoelectric element 8 for monitoring has a length of 0.3 mm and a width of 0.05 mm, the driving frequency is 6 kHz, the deflection angle of the mirror section 12 is ± 10 degrees, and the deflection angle is stable. An optical reflection element excellent in the above could be produced.

(Embodiment 2)
Hereinafter, the configuration of the optical reflecting element according to Embodiment 2 of the present invention will be described with reference to the drawings.

  FIG. 5 is a plan view of the optical reflecting element according to the second embodiment.

  The basic configuration of the optical reflecting element in the second embodiment is substantially the same as that of the first embodiment, and detailed description of the same components is omitted, and the optical reflecting element in the second embodiment is implemented. The structure of the characteristic part which is greatly different from the first embodiment will be described with reference to the drawings.

  FIG. 5 is characterized in that the first support portion 2 has a meander shape, which is largely different from the configuration of FIG. As a result, the resonance characteristics of the torsional vibration of the tuning fork vibrator 6 and the torsional vibration of the mirror section 12 are improved, and a torsional vibrator having a high Q value can be obtained, and the influence of unnecessary disturbance vibration can be eliminated. A reflective element can be realized. Further, since the high Q value can be realized, the driving voltage can be set to low voltage driving. The monitoring piezoelectric element 8 is formed on a part of the second support portion 11.

  Then, the center of the meander shape of the first support portion 2 is arranged on the same line as the rotation axis 14 of the mirror portion 12 in the same manner as described for the feature of the second support portion 11 having the meander shape. Further, it is preferable that the meander shape is symmetrical with respect to the rotation axis 14. Further, by arranging the meander shape on the same plane as the tuning fork vibrator 6, an optical reflecting element having excellent productivity can be obtained.

  As described above, by forming the first support portion 2 and the second support portion 11 in a meander shape, it is possible to realize an optical reflecting element having a high Q value, thereby reducing the influence of disturbance vibration. It is possible to realize an optical reflecting element that is difficult to receive and can be driven at a low voltage.

  INDUSTRIAL APPLICABILITY The present invention is advantageous in that the optical reflecting element is miniaturized and enables highly accurate vibration control, and is particularly useful for electrophotographic copying machines, laser printers, and optical scanners.

The top view of the optical reflection element in Embodiment 1 of this invention Sectional view in the AA part of FIG. Schematic diagram for explaining the operation state The top view for demonstrating the structure of the piezoelectric element for monitors The top view of the optical reflective element in Embodiment 2 of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support body 2 1st support part 3 1st arm 4 2nd arm 5 Connection part 6 Tuning fork vibrator 7a, 7b Arrow 8 Monitor piezoelectric element 9 Vibration center 10, 10a, 10b Piezoelectric actuator 11 Second support Part 12 Mirror part 13 Arrow 14 Rotating shaft 17, 18, 19 Wiring pattern 20 Base material 21 First electrode layer 22 Piezoelectric layer 23 Second electrode layer 25, 25 a, 25 b, 25 c, 25 d Connection terminal

Claims (18)

A support, a first support having one end supported by the support, a tuning fork vibrator having a first arm and a second arm supported by the other end of the first support, and A second support part having one end supported at the vibration center of the tuning fork vibrator, and a mirror part supported by the other end of the second support part, the second support part having a meander shape, An optical reflecting element in which a monitoring piezoelectric element for controlling vibration is provided on a part of the second support portion. The optical reflecting element according to claim 1, wherein the monitoring piezoelectric element is provided so as to be orthogonal to the rotation axis of the mirror portion of the tuning fork vibrator. 2. The optical reflecting element according to claim 1, wherein the first arm and the second arm are flexibly vibrated in directions in which the phases of the first arm and the second arm are different by 180 degrees, and the tuning fork vibrator is vibrated so that the tuning fork vibrator is torsionally vibrated about the rotation axis. . The optical reflection element according to claim 1, wherein the resonance frequency of the tuning fork vibrator and the resonance frequency of the torsional vibrator formed of the mirror part and the second support part are substantially the same frequency. The optical reflection element according to claim 1, wherein the meander-shaped axis center is arranged on the same line as the rotation axis of the mirror portion. The optical reflection element according to claim 1, wherein the meander shape is symmetrical with respect to the rotation axis. The optical reflecting element according to claim 1, wherein the meander shape is arranged on the same plane as the tuning fork vibrator. The optical reflection element according to claim 1, wherein the first support portion has a meander shape. The optical reflection element according to claim 8, wherein the meander-shaped axis center is arranged on the same line as the rotation axis of the mirror portion. The optical reflection element according to claim 8, wherein the meander shape is bilaterally symmetrical about the rotation axis. The optical reflecting element according to claim 8, wherein the meander shape is arranged on the same plane as the tuning fork vibrator. The optical reflective element according to claim 1, wherein the base material of the first support part, the tuning fork vibrator, the second support part, and the mirror part is made of the same material. The optical reflective element according to claim 1, wherein the base material of the optical reflective element is an elastic member. The optical reflecting element according to claim 13, wherein the elastic member is made of metal, quartz, glass, or quartz. The optical reflective element according to claim 14, wherein the metal is silicon, titanium, stainless steel, Elinvar, or a brass alloy. The optical reflective element according to claim 1, wherein a piezoelectric actuator is provided on at least one surface of the first arm and / or the second arm. The optical reflective element according to claim 16, wherein the piezoelectric actuator is a laminated piezoelectric thin film comprising a first electrode layer, a piezoelectric layer, and a second electrode layer. The optical reflecting element according to claim 17, wherein a piezoelectric actuator is provided on the same surface of the tuning fork vibrator.

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