JP2009192781A - Optical reflection element - Google Patents

Abstract

An object of the present invention is to downsize an optical reflecting element.
In order to achieve this object, the present invention is directed to a first mirror portion, which is opposed to the mirror portion 1 via the mirror portion 1, and is connected to the mirror portion 1 by a first support portion 2, respectively. The tuning fork-shaped piezoelectric vibrator 3 and the frame 6 surrounding the outer periphery of the first tuning-fork piezoelectric vibrator 3 are connected to the vibration center of the first tuning-fork piezoelectric vibrator 3 by the second support portion 5. And the second tuning-fork type piezoelectric vibrator 8 which is opposed to each other through the frame body 6 and is connected to the frame body 6 by a third support portion 7 and the second tuning-fork type piezoelectric vibrations. A vibration center of the child 8 and a support body 11 connected by a fourth support portion 10 are provided. The opposing direction of the pair of first tuning fork type piezoelectric vibrators 3 and the pair of second tuning fork type piezoelectric vibrators. It was assumed that there was a relationship orthogonal to the facing direction of 8. Thereby, this invention can implement | achieve a small optical reflective element.
[Selection] Figure 1

Description

  The present invention relates to an optical reflection element used for a laser display or the like.

  Conventionally, a galvanometer mirror etc. are mentioned as an optical reflective element which sweeps the light emitted from the laser used for a laser display etc.

  The galvano mirror includes a mirror part, a coil arranged on the outer periphery of the mirror part, and a magnet arranged outside the coil, generates a magnetic field inside the magnet, and supplies a current to the coil in the magnetic field. Electromagnetic force is generated by flowing. And a mirror part is driven by this electromagnetic force, and a laser beam is swept on a screen surface by reflecting a laser beam by the rotating mirror part (for example, refer patent document 1).

In recent years, with the miniaturization of such a laser display, miniaturization of the optical reflecting element has become a proposition.
JP 7-218857 A

  It is difficult to reduce the size of conventional optical reflecting elements.

  This is because a magnet for driving the mirror portion requires a large arrangement area.

  Therefore, an object of the present invention is to reduce the size of the optical reflecting element.

  In order to achieve this object, the present invention provides a pair of first tuning fork-shaped piezoelectric elements that are opposed to each other via a mirror part and are connected to the mirror part by a first support part. The vibrator is connected to the vibration center of each of the first tuning fork-shaped piezoelectric vibrators by the second support portion and surrounds the outer periphery of the pair of first tuning-fork piezoelectric vibrators, And a pair of second tuning-fork type piezoelectric vibrators connected to the frame body by a third support portion, and the vibration centers of the second tuning-fork type piezoelectric vibrators, respectively, Each of the first tuning fork-type piezoelectric vibrators has a first arm and a second arm on both sides of the first support portion, respectively, and a second tuning fork. Each piezoelectric vibrator has a third arm and a fourth arm on both sides of the third support part. And the opposing direction of the first tuning fork piezoelectric vibrator pair was assumed to be in a relationship perpendicular to the opposing direction of the pair second tuning fork piezoelectric vibrator.

  Thereby, the present invention can reduce the size of the optical reflecting element.

  The reason is that the mirror portion can be excited by bending and vibrating the arm of the tuning fork type piezoelectric vibrator by piezoelectric driving. As a result, the optical reflecting element can be reduced in size.

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

  In FIG. 1, the optical reflecting element is a pair of first tuning fork shapes that are opposed to the mirror portion 1 via the mirror portion 1 and are connected to the mirror portion 1 by the respective first support portions 2. A frame body that is connected to the piezoelectric vibrator 3 and the vibration center 4 of the first tuning-fork type piezoelectric vibrator 3 by the second support portion 5 and surrounds the outer periphery of the pair of first tuning-fork type piezoelectric vibrators 3. 6 and a pair of second tuning-fork-type piezoelectric vibrators 8 which are opposed to each other via the frame body 6 and are connected to the frame body 6 by a third support portion 7, respectively. A vibration center 9 of the piezoelectric vibrator 8 and a frame-shaped support body 11 each connected by a fourth support portion 10 are provided.

  The first tuning-fork type piezoelectric vibrator 3 has a first arm 12 and a second arm 13 on both sides of the first support part 2, respectively. Each has a third arm 14 and a fourth arm 15 on both sides of the third support portion 7.

  Moreover, in this Embodiment, the 1st support part 2 and the 2nd support part 5 are on the straight line parallel to the X-axis of FIG. 1, and the 3rd support part 7 and the 4th support part 10 are , On a straight line parallel to the Y-axis of FIG. The opposing direction of the pair of first tuning fork type piezoelectric vibrators 3 is parallel to the X axis, and the opposing direction of the pair of second tuning fork type piezoelectric vibrators 8 is parallel to the Y axis. They are orthogonal.

  In the present embodiment, the first tuning fork type piezoelectric vibrator 3 has a rotation axis parallel to the X axis in FIG. 1, and the second tuning fork type piezoelectric vibrator 8 has a rotation axis parallel to the Y axis. The rotation axis of the first tuning fork type piezoelectric vibrator 3 and the rotation axis of the second tuning fork type piezoelectric vibrator 8 are formed so as to be orthogonal to each other substantially at the center of the mirror portion 1.

  In this embodiment, as shown in FIG. 2, the substrate 16 of the optical reflecting element is made of a material having elasticity, mechanical strength, and high Young's modulus, such as a metal, glass, or ceramic substrate. From the viewpoint of mechanical properties and availability, for example, it is preferable to use a metal, quartz, glass, quartz, or ceramic material. Furthermore, if a metal such as silicon, titanium, stainless steel, Elinvar, or a brass alloy is used, an optical reflecting element having excellent vibration characteristics and workability can be realized.

  And in this Embodiment, as shown in FIG. 1, the 1st arm 12, the 2nd arm 13, the 3rd arm 14, and the 4th comprised with base materials, such as silicon | silicone (16 of FIG. 2). Each of the arms 15 is formed with a piezoelectric actuator 17 on at least one surface for causing flexural vibration.

  In this embodiment, as shown in FIG. 2, the piezoelectric actuator 17 is a thin film laminated piezoelectric actuator 17 having a laminated structure of a lower electrode layer 18, a piezoelectric layer 19, and an upper electrode layer 20. Thereby, the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8 can be made thinner. In the present embodiment, the lower electrode layer 18 and the piezoelectric layer 19 are formed in common by the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8, and the upper electrode layer 20 is respectively formed. It was formed so as to be electrically independent.

  Further, by making the thickness of the first tuning-fork type piezoelectric vibrator 3 smaller than the width dimension of the first arm 12 and the second arm 13 shown in FIG. Can be realized. Similarly, by making the thickness of the second tuning-fork type piezoelectric vibrator 8 smaller than the width dimension of the third arm 14 and the fourth arm 15 shown in FIG. 1, it contributes to miniaturization of the optical reflecting element.

  The lower electrode layer 18, the piezoelectric layer 19, and the upper electrode layer 20 are sequentially sputtered on the base material 16 that forms the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8. It can form by thin film processes, such as. Therefore, the piezoelectric actuator 17 is preferably formed on the surfaces of the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8 from the viewpoint of productivity.

  The piezoelectric material used for the piezoelectric layer 19 is preferably a piezoelectric material having a high piezoelectric constant such as lead zirconate titanate (PZT).

  Further, the resonance frequency of the first tuning-fork type piezoelectric vibrator 3 and the resonance frequency of the torsional vibrator constituted by the mirror part 1 and the first support part (2 in FIG. 1) are substantially the same frequency. By designing the vibration, it is possible to realize an optical reflection element that efficiently and repeatedly vibrates the mirror unit 1.

  Similarly, the resonance frequency of the second tuning-fork type piezoelectric vibrator 8 and the resonance frequency of the torsional vibrator constituted by the frame body 6 and the third support portion 7 are designed to be substantially the same frequency. Is preferred.

  Moreover, in this Embodiment, the 2nd support part 5 is formed so that it may enter into the frame 6 side. That is, in order to efficiently torsionally vibrate the mirror part 1 and the first support part 2, it is necessary to make the resonator lengths of the second support part 5 and the first support part 2 as equal as possible. By inserting the second support portion 5 into the inside of the frame body 6, the second support portion 5 can be disposed in a space-saving manner even if the second support portion 5 is long, and the optical reflecting element can be made compact. Can be

  Further, in the present embodiment, since the second support portion 5 is inserted into the frame body 6 side, the width of the frame body 6 is narrow, but the width of the first tuning fork type piezoelectric vibrator 3 is It has not changed. That is, in a narrow region, stress concentrates locally and an unnecessary vibration mode may occur. However, in the present embodiment, the first tuning-fork type piezoelectric vibrator 3 has substantially the same width as a whole. Therefore, the stress can be evenly distributed and can be vibrated stably.

  Furthermore, in the present embodiment, the third support portion 7 enters the frame body 6 and the second tuning fork-shaped piezoelectric vibrator 8 side, and the fourth support portion 10 enters the support body 11 side. is there. As a result, the optical reflecting element can be reduced in size, and the width of the second tuning-fork type piezoelectric vibrator 8 can be prevented from changing locally, and can be vibrated stably.

  Further, it is preferable that the third support portion 7 is inserted into the frame body 6 side longer than the second tuning-fork type piezoelectric vibrator 8 side. Conversely, if the second tuning fork type piezoelectric vibrator 8 is inserted long, the shape in the vicinity of the vibration center 9 becomes complicated, and an unnecessary vibration mode may occur in the second tuning fork type piezoelectric vibrator 8 in some cases. It is.

  Furthermore, by making the widths of the first arm 12, the second arm 13, and their connecting portions 21 and the third arm 14, the fourth arm 15 and their connecting portions 22 equal, Unnecessary vibration modes generated in the reflective element can be reduced.

  Unnecessary vibration modes can also be suppressed by making the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8 U-shaped.

  In the present embodiment, the upper electrode layers of the piezoelectric actuators 17 formed on the first arm 12, the second arm 13, the third arm 14, and the fourth arm 15 shown in FIG. The extraction electrodes of the lower electrode layer are connected to the connection terminals 23A to 23D, 24 while individually forming extraction lines (not shown). As a result, opposite electrical signals can be applied to the first arm 12 and the second arm 13, and opposite electrode signals can be applied to the respective piezoelectric actuators 17 to the third arm 14 and the fourth arm 15. it can.

  In the present embodiment, monitor electrodes (not shown) are arranged on the first arm 12, the second arm 13, the third arm 14, and the fourth arm 15, respectively, and these are also the same as the upper electrode. It was connected to connection terminals 25A to 25D while being routed on the element. As a result, the input signal can be adjusted while detecting the amplitude of each of the first, second, third, and fourth arms 12, 13, 14, and 15, and stable self-excited drive can be realized.

  Note that the lead lines of the piezoelectric actuator 17 and the monitor electrodes and the lead lines thereof are not shown in FIG.

  Next, the operation principle of the optical reflecting element having such a configuration will be described.

  When an alternating drive voltage is applied between the lower electrode layer 18 and the upper electrode layer 20 shown in FIG. 2, the piezoelectric layer 19 expands and contracts in the plane direction, and the first arm (12 in FIG. 1) and the first The second arm 13 bends and vibrates in the direction perpendicular to the substrate 16.

  At this time, if a drive signal opposite to the positive and negative is applied to each piezoelectric actuator 17 formed on the first arm 12 and the second arm 13, as shown in FIG. The arm 13 can be flexibly vibrated in a direction (in the direction of arrows 26 and 27) that is 180 degrees out of phase, that is, in the opposite direction. Here, in the present embodiment, the first and second arms 12 and 13 can be greatly bent and vibrated because of the cantilever structure having the distal ends thereof as free ends.

  The vibration energy of the first arm 12 and the second arm 13 is propagated to the connecting portion 21 of the first tuning-fork type piezoelectric vibrator 3. As a result, the first tuning-fork type piezoelectric vibrator 3 repeats rotational vibration (torsional vibration) at a predetermined frequency about the rotation axis 28 with the straight line passing through the vibration center 4 as the rotation axis 28.

  Next, the vibration energy of this repetitive rotational vibration is transmitted to the first support part 2 joined to the connecting part 21, and the torsional vibrator constituted by the first support part 2 and the mirror part 1 The torsional vibration is caused in the arrow direction 29 around the rotation shaft 28. As a result, repetitive rotational vibration is caused in the mirror unit 1 with the rotation shaft 28 as the axis. At this time, the direction of the repetitive rotational vibration of the first tuning-fork type piezoelectric vibrator 3 and the direction of the repetitive rotational vibration of the torsional vibrator composed of the first support part 2 and the mirror part 1 are opposite to each other by 180 degrees. It will vibrate in the direction.

  The second tuning-fork type piezoelectric vibrator 8 shown in FIG. 1 also applies a voltage between the lower electrode layer and the upper electrode layer, and causes the third arm 14 and the fourth arm 15 to have directions that are 180 degrees different from each other. Torsional vibration is caused around the rotation axis passing through the vibration center 9.

  Then, when this vibration energy propagates to the third support portion 7 via the connecting portion 22, the torsional vibrator composed of the third support portion 7 and the frame body 6 is moved to the second center around the rotation axis. It is possible to repeatedly rotate and vibrate in the opposite phase to the tuning fork type piezoelectric vibrator 8.

  When the frame body 6 is tilted, the mirror portion 1 supported by the frame body 6 is also tilted, and the mirror portion 1 can be repeatedly rotated and vibrated.

  A light beam generated from, for example, a laser light source or an LED light source is input to the mirror unit 1 and reflected by the vibrating mirror unit 1 to scan the light beam on the screen. In the present embodiment, since the rotation axes of the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8 are orthogonal to each other, the light emitted from the mirror unit 1 is directed in the vertical and horizontal directions of the screen. Can be scanned.

  In the present embodiment, light is scanned in the horizontal direction by driving by the first tuning fork type piezoelectric vibrator 3, and light is scanned in the vertical direction by driving by the second tuning fork type piezoelectric vibrator 8.

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

  First, a silicon substrate having a thickness of about 0.3 mm to be the base material 16 is prepared, and a lower electrode layer 18 made of a platinum electrode is formed thereon using a thin film process such as sputtering or vapor deposition.

  Thereafter, a piezoelectric layer 19 is formed on the lower electrode layer 18 by a sputtering method or the like using a piezoelectric material such as lead zirconate titanate (PZT). At this time, an oxide dielectric containing Pb and Ti is preferably used as the orientation control layer between the piezoelectric layer 19 and the lower electrode layer 18, and an orientation control layer made of PLMT is more preferably formed. . Thereby, the crystal orientation of the piezoelectric layer 19 is further increased, and the piezoelectric actuator 17 having excellent piezoelectric characteristics can be realized.

  Next, an upper electrode layer 20 made of titanium / gold is formed on the piezoelectric layer 19.

  At this time, titanium below the upper electrode layer 20 is formed in order to increase the adhesion with the piezoelectric layer 19 such as a PZT thin film, and a metal such as chromium can be used in addition to titanium. As a result, since a diffusion layer that is excellent in adhesion to the piezoelectric layer 19 and is strong with the gold electrode is formed, the piezoelectric actuator 17 having high adhesion strength can be formed. In this embodiment, the thickness of the platinum lower electrode layer 18 is 0.2 μm, the piezoelectric layer 19 made of PZT is 3.5 μm, the titanium portion of the upper electrode layer 20 is 0.01 μm, and the gold electrode portion. Is formed at 0.3 μm.

  Next, the lower electrode layer 18, the piezoelectric layer 19, and the upper electrode layer 20 are etched using a photolithographic technique, and the piezoelectric actuator 17 is patterned.

  At this time, a predetermined electrode pattern was formed using an etching solution composed of an iodine / potassium iodide mixed solution, ammonium hydroxide, and hydrogen peroxide mixed solution as an etching solution for the upper electrode layer 20.

  Moreover, as an etching method used for the lower electrode layer 18 and the piezoelectric layer 19, 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.

  In addition, there is a method in which the piezoelectric layer 19 is patterned by wet etching using a mixed solution of hydrofluoric acid, nitric acid, acetic acid and hydrogen peroxide, and then the lower electrode layer 18 is further etched and patterned by dry etching. .

Next, the silicon substrate is isotropically dry-etched using XeF ₂ gas to remove unnecessary silicon portions and perform patterning to form the base material 16 as shown in FIG. An optical reflection element having a shape as shown can be formed.

In addition, when etching a silicon substrate with higher accuracy, dry etching utilizing the anisotropy of silicon is preferable. In this case, etching can be performed more linearly by using a mixed gas of SF ₆ gas that promotes etching and C ₄ F ₈ gas that suppresses etching, or by alternately switching these gases.

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

By the manufacturing process as described above, for example, the size of the mirror portion 1 is 1.0 mm × 1.0 mm, the size of the support 11 is 5.8 mm × 5.8 mm, the thickness is 0.03 mm, the driving frequency; f _H An optical reflecting element having characteristics of (horizontal) 22 kHz, f _V (vertical) 0.5 kHz, deflection angle of the mirror section 1; θ _H (horizontal) ± 5 degrees, θ _V (vertical) ± 5 degrees is manufactured. be able to.

  In the present embodiment, the mirror part 1, the first support part 2, the first tuning fork-shaped piezoelectric vibrator 3, the second support part 5, the frame 6, the third support part 7, and the second tuning fork form. By integrating the piezoelectric vibrator 8, the fourth support portion 10, and the base material 16 of the support body 11 from the same base material 16, a stable vibration characteristic and an optical reflective element with excellent productivity can be realized. can do.

  Further, the optical reflecting element in the present embodiment can be manufactured in a lump with high precision by applying a semiconductor process such as a thin film process or a photolithographic technique on the base material 16 such as a silicon wafer, and the optical reflecting element. It is possible to realize an optical reflective element that is small in size, high in accuracy, and excellent in production efficiency.

  The mirror portion 1 can also be formed by mirror polishing the surface of the substrate 16, but a gold or aluminum metal thin film having excellent light reflection characteristics can also be formed as a mirror film. In this embodiment, since gold is used as the upper electrode layer 20, this gold film can be used as a mirror film as it is, and the production efficiency is also increased.

  The effect of this embodiment will be described below.

  In the present embodiment, the optical reflecting element can be reduced in size.

  The first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8 as shown in FIG. 1 are used, so that the first arm 12, the second arm 13, and the third arm are respectively used. 14 because the mirror unit 1 can be repeatedly rotated and vibrated by utilizing the flexural vibration of the fourth arm 15.

  Therefore, the mirror unit 1 can be excited without using a magnet having a large arrangement area, which contributes to miniaturization of the element.

  Further, since the tip of the arm becomes a free end by making the drive source a tuning fork, the deflection angle of the mirror portion 1 can be efficiently increased even if it is small.

  Further, by making the vibration source a tuning fork having a high Q value, a large vibration energy can be obtained with a small energy, which contributes to the miniaturization of the element.

  Further, by designing the vibration of the first tuning-fork type piezoelectric vibrator 3 and the second tuning-fork type piezoelectric vibrator 8, the reflection angle of the output light can be greatly changed, and the input light such as a laser beam is predetermined. It is possible to realize an optical reflecting element that can be swept so that the design value becomes.

  Further, in the embodiment, the mirror unit 1 is surrounded by a pair of first tuning fork type piezoelectric vibrators 3 from both sides thereof, and the outer periphery of these first tuning fork type piezoelectric vibrators 3 is surrounded by a frame body 6. 6 is surrounded by a pair of second tuning fork type piezoelectric vibrators 8 from both sides, and the outer periphery of these second tuning fork type piezoelectric vibrators 8 is surrounded by a support 11, so that each member is interposed through a small gap. The structure is such that it is wound in several layers, reducing the dead space of the entire device and reducing the size of the device.

  In the present embodiment, the first, second, third, and fourth arms 12, 13, 14, and 15 are easy to process because they are each linear.

  In the present embodiment, since the first tuning fork-shaped piezoelectric vibrator 3 is symmetrically disposed on both sides of the mirror unit 1, the mirror unit 1 can be excited stably and bilaterally. Since the center is a fixed point, light can be scanned stably.

  Moreover, since the mirror part 1 has a both-end support structure in which both ends are supported by the first support part 2, unnecessary resonance of the mirror part 1 can be suppressed, and the influence of disturbance vibration can be reduced.

  Further, in the present embodiment, since the second tuning fork-shaped piezoelectric vibrator 8 is symmetrically disposed on both sides of the frame body 6, the center of the frame body 6 can be excited with the fixed point.

  Further, since the frame body 6 has a both-end support structure in which both ends are supported by the third support portion 7, unnecessary resonance of the frame body 6 can be suppressed, and the influence of disturbance vibration can be reduced.

  In the above embodiment, the piezoelectric actuators 17 are formed on both the first arm 12 and the second arm 13, but the piezoelectric actuators 17 may be formed only on at least one of them. This utilizes the characteristics of a tuning fork type piezoelectric vibrator. When one of the arms vibrates, the kinetic energy propagates to the other arm via the connecting portion 21, and the other arm can be excited. Because it can.

  Similarly, the second tuning-fork type piezoelectric vibrator 8 is operated in the same manner as when the piezoelectric actuator 17 is formed only on one of the third arm 14 and the fourth arm 15. be able to.

  In the present embodiment, the piezoelectric actuator 17 is formed only on one side of the arm in both the first and second tuning-fork type piezoelectric vibrators 3 and 8, but may be formed on both sides. Further, since the first tuning fork type piezoelectric vibrator 3 has a smaller area than the second tuning fork type piezoelectric vibrator 8 and a weak driving force, only the first tuning fork type piezoelectric vibrator 3 is provided on both surfaces of the substrate 16. The piezoelectric actuator 17 may be formed.

  In addition, if each cross-sectional shape of the 1st support part 2, the 2nd support part 5, the 3rd support part 7, and the 4th support part 10 is circular, the vibration mode of torsional vibration will be stabilized, Unnecessary resonance can also be suppressed, and an optical reflection element that is hardly affected by disturbance vibration can be realized.

  The optical reflection element as described above can be applied to, for example, an image projection apparatus. That is, light can be incident on the mirror unit 1 that vibrates in the biaxial direction, the light can be reflected by the mirror unit 1, and the light can be projected two-dimensionally to project a drawing. In addition, it can be used for a laser exposure machine.

(Embodiment 2)
The main difference between the optical reflecting element in the present embodiment and the optical reflecting element in the first embodiment is the shape and location of the piezoelectric actuator 17 as shown in FIG.

  That is, in the present embodiment, in the first tuning-fork type piezoelectric vibrator 3, the piezoelectric actuator 17 is extended to the connecting portion 21 between the first arm 12 and the second arm 13 and configured in an L shape. . The first arm 12 and the second arm 13 are applied with signals having opposite phases, respectively, so that the drive electrodes of the piezoelectric actuator 17 formed thereon are not electrically short-circuited with each other. The vibration is interrupted at the vibration center 4 of the piezoelectric vibrator 3.

  Similarly, in the second tuning-fork type piezoelectric vibrator 8, the piezoelectric actuator 17 is extended to the connecting portion 22 between the third arm 14 and the fourth arm 15.

  Thus, by forming the piezoelectric actuator 17 up to the connecting portion 22, the area can be effectively used and a large drive source can be obtained.

  In the present embodiment, the shape of the piezoelectric actuator 17 is L-shaped for both the first tuning-fork type piezoelectric vibrator 3 and the second tuning-fork type piezoelectric vibrator 8, but only one of them may be formed. In either case, the tuning fork-shaped piezoelectric vibrators to be paired can have the same shape of the piezoelectric actuator 17 to stably excite the mirror unit 1 with the center as a fixed point.

  Description of other configurations and effects similar to those of the first embodiment will be omitted.

(Embodiment 3)
The main difference between the present embodiment and the first embodiment is that, as shown in FIG. 5, each first tuning-fork type piezoelectric vibrator 3 includes a first arm 12 and a second arm 13, and A fifth support 30 is provided between the first support 2 and each second tuning-fork type piezoelectric vibrator 8 includes a third arm 14 and a fourth arm 15 and a third support. The sixth support portion 31 is provided between the portion 7 and the portion 7.

  The fifth support portion 30 and the first support portion 2 are orthogonal to each other, and the sixth support portion 31 and the third support portion 7 are orthogonal to each other.

  In the present embodiment, the energy of repetitive rotational vibration of the first tuning-fork type piezoelectric vibrator 3 propagates to the first support part 2 via the fifth support part 30, and this first support part 2 Can be efficiently torsionally vibrated, contributing to the miniaturization of the optical reflecting element. The energy of repetitive rotational vibration of the second tuning-fork type piezoelectric vibrator 8 is also propagated to the third support portion 7 via the sixth support portion 31 and efficiently torsionally vibrates the third support portion 7. I can do it.

  The fifth support portion 30 is preferably provided in a vibration node portion of a higher-order standing wave having a resonance frequency of the torsional vibrator constituted by the first support portion 2 and the mirror portion 1. That is, this standing wave appears as an integral number as shown by 1/2, 1/3, and 1/4, and a fifth support portion is added to the vibration node of the predetermined standing wave. By providing 30, vibration energy can be propagated more efficiently.

  In addition, the fifth support portion 30 is a fixed end side of the first arm 12 and the second arm 13, that is, the vibration center 4 of the first tuning-fork type piezoelectric vibrator 3 than the mirror portion 1. It is more preferable to form at a position close to. This is because if the fifth support portion 30 is formed on the free end side, the flexural vibrations of the first arm 12 and the second arm 13 are constrained, and the amplitude becomes smaller.

  Further, for the same reason, the sixth support portion 31 is preferably provided at the vibration node portion of the higher-order standing wave of the resonance frequency of the torsional vibrator constituted by the third support portion 7 and the frame body 6, Further, it is preferable to form it at a position closer to the vibration center 9 of the second tuning-fork type piezoelectric vibrator 8 than the frame body 6.

  As described above, in the present embodiment, an optical reflecting element having a large amplitude can be realized by the fifth support portion 30 and the sixth support portion 31, which contributes to downsizing.

  In addition, in this Embodiment, although both the 5th support part 30 and the 6th support part 31 were formed, either one may be sufficient. Also in this case, for example, when the fifth support portion 30 is provided, it is desirable that the fifth support portion 30 be formed on both of the first tuning fork type piezoelectric vibrators 3 to be paired. Thereby, it can be rotated symmetrically by making the center of the mirror part 1 into a fixed point.

  Description of other configurations and effects similar to those of the first embodiment will be omitted.

(Embodiment 4)
The main difference between the present embodiment and the first embodiment is that, as shown in FIG. 6, the pair of first tuning fork-shaped piezoelectric vibrators 3 are arranged between the opposed first arms 12 and the opposed second arms. The arms 13 are connected by elastic bodies 32.

  The elastic body 32 has a smaller elasticity (softer) than the base material of the optical reflecting element, and is formed of a stretchable resin film in the present embodiment, and the first arm 12 or the second arm 13. Is pasted.

  As this resin film, a material having higher elasticity in the direction parallel to the extending direction of the first arm 12 and the second arm 13 is preferable.

  In this embodiment, a resin is used as the elastic body, but other materials such as a rubber material or a metal having a small elasticity and a small thickness may be used.

  In this way, by connecting the first arm 12 and the second arm 13 with the elastic body 32, a slight shift in the resonance frequency of the opposing first tuning-fork type piezoelectric vibrator 3 can be corrected. Can do. Further, the symmetry of flexural vibration is increased, unnecessary vibration at the free end of the arm can be suppressed, and the driving force is increased.

  In the present embodiment, the first arm 12 and the second arm 13 of the first tuning fork type piezoelectric vibrator 3 are connected by the elastic body 32. The third arm 14 and the fourth arm 15 may be connected by an elastic body 32. In this case, it is preferable to use a material having higher elasticity in the direction parallel to the extending direction of the third arm 14 and the fourth arm 15 as the elastic body 32.

  By providing the elastic body 32 in this way, it is possible to correct the deviation of the resonance frequency of the opposing second tuning-fork-type piezoelectric vibrator 8 and to improve the symmetry of flexural vibration, thereby suppressing unnecessary vibration of the arm. This increases the driving force.

  Description of other configurations and effects similar to those of the first embodiment will be omitted.

(Embodiment 5)
As shown in FIG. 7, the main difference between the present embodiment and the first embodiment is that the first tuning fork-shaped piezoelectric vibrator 3 has an interval between the tips of the first arm 12 and the second arm 13. d ₁ is a point shorter than the maximum length d ₂ (diameter) of the mirror portion 1 perpendicular to the first and second arms 12 and 13.

  That is, in the present embodiment, the first and second arms 12 and 13 of the first tuning fork-shaped piezoelectric vibrator 3 do not surround the outer periphery of the mirror portion 1 and are enclosed more inside. As a result, the optical reflecting element can be reduced in size.

  The second tuning fork-shaped piezoelectric vibrator 8 has a maximum length of the frame 6 in which the distance between the third arm 14 and the fourth arm 15 is perpendicular to the third and fourth arms 14 and 15. That is, it is good also as a structure shorter than the length of the side which the 3rd support part 7 of the frame 6 has joined.

  Description of other configurations and effects similar to those of the first embodiment will be omitted.

  The present invention has an effect that the optical reflecting element can be miniaturized, 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 of the optical reflecting element (cross section AA in FIG. 1) Schematic diagram showing the operating state of the optical reflection element The top view of the optical reflective element in Embodiment 2 of this invention The top view of the optical reflective element in Embodiment 3 of this invention The top view of the optical reflective element in Embodiment 4 of this invention Plan view of an optical reflecting element in Embodiment 5 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mirror part 2 1st support part 3 1st tuning fork type piezoelectric vibrator 4 center of vibration 5 2nd support part 6 Frame 7 3rd support part 8 2nd tuning fork type piezoelectric vibrator 9 center of vibration 10 1st Four support portions 11 Support body 12 First arm 13 Second arm 14 Third arm 15 Fourth arm 16 Base material 17 Piezoelectric actuator 18 Lower electrode layer 19 Piezoelectric layer 20 Upper electrode layer 21 Connection portion 22 Connection Part 23A-23D Connection terminal 24 Connection terminal 25A-25D Connection terminal 26, 27 Arrow 28 Rotating shaft 29 Arrow 30 Fifth support part 31 Sixth support part 32 Elastic body

Claims (18)

Mirror part,
A pair of first tuning fork-shaped piezoelectric vibrators that are opposed to each other through the mirror part and are connected to the mirror part by a first support part,
A frame body that is connected to a vibration center of each of the first tuning fork type piezoelectric vibrators by a second support portion and surrounds an outer periphery of the pair of first tuning fork type piezoelectric vibrators;
A pair of second tuning-fork type piezoelectric vibrators opposed to each other through the frame body and connected to the frame body by a third support portion;
The vibration center of these second tuning-fork type piezoelectric vibrators and a support body respectively connected by a fourth support portion,
Each of the first tuning fork-shaped piezoelectric vibrators has a first arm and a second arm on both sides of the first support part,
The second tuning-fork type piezoelectric vibrator has a third arm and a fourth arm on both sides of the third support part,
An optical reflecting element in which a facing direction of the pair of first tuning fork type piezoelectric vibrators is orthogonal to a facing direction of the pair of second tuning fork type piezoelectric vibrators. The first tuning-fork type piezoelectric vibrator is
The first arm and the second arm are driven to bend and vibrate in directions different in phase by 180 degrees, and torsionally vibrate around the rotation axis,
The second tuning-fork type piezoelectric vibrator is
The third arm and the fourth arm are flexed and vibrated in directions different in phase by 180 degrees,
The optical reflecting element according to claim 1, wherein the optical reflecting element is driven to torsionally vibrate about the rotation axis. The optical reflection element according to claim 1, wherein the resonance frequency of the first tuning-fork type piezoelectric vibrator and the resonance frequency of the torsional vibrator constituted by the mirror part and the first support part are substantially the same frequency. . The optical reflection element according to claim 1, wherein a resonance frequency of the second tuning-fork type piezoelectric vibrator and a resonance frequency of a torsional vibrator constituted by the frame and the third support part are set to substantially the same frequency. . At least one of the first arm and the second arm;
The optical reflecting element according to claim 1, wherein a piezoelectric actuator is provided on at least one of the third arm and the fourth arm. At least one of the first arm and the second arm is provided with a piezoelectric actuator,
This piezoelectric actuator
The optical reflection element according to claim 1, wherein the optical reflection element extends to a connecting portion between the first arm and the second arm. At least one of the third arm and the fourth arm is provided with a piezoelectric actuator,
This piezoelectric actuator
The optical reflection element according to claim 1, wherein the optical reflection element extends to a connection portion between the third arm and the fourth arm. The optical reflection element according to claim 1, wherein the second support portion enters the frame body side. 2. The optical reflecting element according to claim 1, wherein the third support portion enters at least one of the frame body side and the second tuning fork-shaped piezoelectric vibrator side. The third support part enters the second tuning-fork type piezoelectric vibrator side,
The optical reflection element according to claim 1, wherein the fourth support portion has a shape that enters the support side. Each of the first tuning-fork type piezoelectric vibrators is
The optical reflective element according to claim 1 which has a 5th support part between said 1st arm and 2nd arm, and the 1st support part. 12. The fifth support portion according to claim 11, wherein the fifth support portion is provided in a vibration node portion of a higher-order standing wave having a resonance frequency of a torsional vibrator constituted by the mirror portion and the first support portion. Optical reflective element. Each of the second tuning-fork type piezoelectric vibrators is
The optical reflective element according to claim 1 which has a 6th support part between said 3rd arm and the 4th arm, and the 3rd support part. 14. The sixth support portion according to claim 13, wherein the sixth support portion is provided in a vibration node portion of a higher-order standing wave having a resonance frequency of a torsional vibrator constituted by the frame body and a third support portion. Optical reflective element. The first tuning-fork type piezoelectric vibrator of the pair is
The optical reflective element according to claim 1, wherein the first arm facing each other and the second arm facing each other are connected by an elastic body. The second tuning-fork type piezoelectric vibrator of the pair is
The optical reflecting element according to claim 1, wherein the third arm facing each other and the fourth arm facing each other are connected by an elastic body. The first tuning-fork type piezoelectric vibrator is
The distance between the tips of the first arm and the second arm is
The optical reflecting element according to claim 1, wherein the optical reflecting element is shorter than a maximum length of a mirror portion perpendicular to the first arm and the second arm. The second tuning-fork type piezoelectric vibrator is
The distance between the tips of the third arm and the fourth arm is
The optical reflecting element according to claim 1, wherein the optical reflecting element is shorter than a maximum length of a frame perpendicular to the third arm and the fourth arm.

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