JP2009265560A - Optical reflection element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the driving accuracy of an optical reflection element. <P>SOLUTION: An optical reflection element is provided with: a mirror 1; a pair of first tuning fork piezoelectric vibrators 3 connected to the mirror 1 via first support beams 2, respectively; a frame body 6 which is connected to the first tuning fork piezoelectric vibrators 3 via second support beams 5, respectively, and encloses the outer periphery of the pair of first tuning fork piezoelectric vibrators 3; second tuning fork piezoelectric vibrators 8 connected to the frame body 6 via third support beams 7, respectively; and a support body 11 connected to the second tuning fork piezoelectric vibrators 8 via fourth support beams 10, respectively, wherein the first tuning fork piezoelectric vibrators 3 have first and second arms 12 and 13 on both sides of the first support beams 2, respectively, at least either one of the pair of first tuning fork piezoelectric vibrators 3 has a first monitor electrode 17 on the first or the second arm 12 or 13. Thus, the driving accuracy of an optical reflection element can be improved. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  As a conventional optical reflecting element, there is an optical reflecting element as shown in FIG. The optical reflecting element includes a mirror unit 101, a frame body 103 that supports the mirror unit 101 via a torsion bar 102, a piezoelectric vibrator 104 that rotates the torsion bar 102 in the frame body 103, A support body 106 that supports the frame body 103 via a torsion bar 105 and a second piezoelectric vibrator 107 that rotates the torsion bar 105 in the support body 106 are provided. The rotation axis of the torsion bar 102 and the rotation axis of the torsion bar 105 are perpendicular to each other.

  This optical reflecting element can be used for a small display device or the like, and the mirror unit 101 is excited by the rotational torque of the torsion bars 102 and 105, and the laser beam is reflected by the rotating mirror unit 101. The laser beam is swept over the screen surface.

In addition, the following patent document 1 is mentioned as literature relevant to this technical field.
JP 2008-20701 A

  These optical reflective elements may have low driving accuracy.

  The reason is that the generated driving force varies due to design errors of the piezoelectric vibrators 104 and 107 and external environmental factors. Therefore, a desired driving force may not be obtained even when a predetermined electric signal is applied.

  Therefore, an object of the present invention is to improve the driving accuracy 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 having a rotation axis perpendicular to the rotation axis of the first tuning-fork type piezoelectric vibrator and being connected to the frame body by a third support portion. Each of the second tuning fork-shaped piezoelectric vibrators and a support body connected by a fourth support portion, and the first tuning-fork type piezoelectric vibrator is provided on both sides of the first support portion. Each of which has a first arm and a second arm. A third arm and a fourth arm are provided on both sides of the third support portion, and at least one of the pair of first tuning fork type piezoelectric vibrators is on the first arm or the second arm. The first monitor electrode was provided.

  Thereby, this invention can improve the drive precision of an optical reflective element.

  This is because the displacement of the first tuning fork type piezoelectric vibrator can be detected by the first monitor electrode. Therefore, if the signal from the first monitor electrode is detected and the electric signal input to the first tuning fork type piezoelectric vibrator is controlled, the first tuning fork type piezoelectric vibrator can be driven in a desired manner. it can. As a result, the driving accuracy of the optical reflecting element can be increased.

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

  As shown in FIG. 1, the optical reflecting element has a pair of first reflecting portions 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. One tuning fork type piezoelectric vibrator 3 and the vibration center 4 of these first tuning fork type piezoelectric vibrators 3 are connected to each other by a second support portion 5, and the outer periphery of the pair of first tuning fork type piezoelectric vibrators 3. A pair of second tuning fork-shaped piezoelectric vibrators 8 that face each other through the frame body 6 and are connected to the frame body 6 by a third support portion 7, and A vibration center 9 of the second tuning-fork type 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.

  In the present embodiment, the first tuning-fork type piezoelectric vibrator 3 has the X axis in FIG. 1 as a rotation axis, and the first support part 2 and the second support part 5 are arranged on the X axis. ing.

  The second tuning-fork type piezoelectric vibrator 8 has a Y axis perpendicular to the X axis as a rotation axis, and a third support portion 7 and a fourth support portion 10 are arranged on the Y axis.

  In the present embodiment, the X axis and the Y axis are formed so as to be orthogonal to each other substantially at the center of the mirror unit 1. As a result, the center of the mirror unit 1 becomes a fixed point, and if light is incident on this fixed part, the optical path length of the light projected on the screen becomes constant, and the image can be projected with high accuracy.

  In the present embodiment, as shown in FIG. 1, each of the pair of first tuning fork-shaped piezoelectric vibrators 3 has a piezoelectric actuator 16 formed on the surface of the first arm 12 facing each other, and A first monitor electrode 17 is formed on the surface of the opposing second arm 13.

  As shown in FIG. 2, the piezoelectric actuator 16 is a thin film laminated type formed on a base material 18 and having a laminated structure of a lower electrode 19, a piezoelectric body 20 and an upper electrode 21. Thereby, the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8 of FIG. 1 can be made thinner.

  Further, as shown in FIG. 2, the first monitor electrode 17 is laminated on the piezoelectric body 20 like the upper electrode 21.

  In the present embodiment, as shown in FIG. 1, the second monitor electrode 22 is formed on the surface of the third arm 14 facing each other in each of the pair of second tuning fork type piezoelectric vibrators 8. In addition, piezoelectric actuators 16 are formed on the surfaces of the fourth arms 15 facing each other.

  The above-described second monitor electrode 22 is laminated on the piezoelectric body (20 in FIG. 2), similarly to the first monitor electrode 17.

  In the present embodiment, the lower electrode 19 and the piezoelectric body 20 shown in FIG. 2 are formed in common by the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8, and the first arm. 12, the upper electrode (not shown) on the fourth arm 15, the first monitor electrode 17, and the second monitor electrode 22 were formed so as to be electrically independent. The wirings of these electrodes are respectively drawn on the piezoelectric body 20 and drawn out to connection terminals 23 to 27 formed on the support body 11. The lower electrode 19 is also drawn out to the connection terminal 28 on the support 11. 2 shows the wiring 29 of the first monitor electrode 17, the wiring 30 of the upper electrode 21 formed on the first arm 12, and the upper electrode (not shown) formed on the fourth arm 15. Each wiring 31 is shown.

  In the present embodiment, each of the pair of first tuning fork type piezoelectric vibrators 3 has the upper electrode 21 on the first arm 12, and electric signals having the same phase are applied to these upper electrodes 21. Therefore, the wiring (30 in FIG. 2) of these upper electrodes 21 may be connected on the frame body 6, for example. Thereby, the number of wirings routed on the element can be reduced, and productivity is increased. In particular, the wiring 30 of the upper electrode 21 can be drawn out to the connection terminal 23 through the frame body 6 via the third support portion 7 and the fourth support portion 10. Since the support portion 10 is very fine, the patterning of the wiring becomes more difficult as the number of wirings increases. However, if a plurality of wirings can be merged on the frame 6 as described above, the number of wirings can be reduced, greatly contributing to productivity improvement, and by securing wiring space, other wirings and electrodes can be connected. It is possible to improve the electrical insulation between the two.

  Each of the first tuning-fork type piezoelectric vibrators 3 to be paired has a first monitor electrode 17 on the second arm 13, and these first monitor electrodes 17 output substantially the same electrical signals in the same phase. In order to detect, the wiring (29 in FIG. 2) of these first monitor electrodes 17 may be connected on the frame 6. Thereby, the number of wirings can be reduced, productivity can be improved, and electrical insulation between the wirings can be increased.

  In the present embodiment, the upper electrode (not shown) wiring 31 formed on the fourth arm 15 and the second monitoring electrode 22 wiring are also formed in pairs. Each may be linked.

  In the present embodiment, 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 are substantially the same frequency. Vibration design. Thereby, the mirror part 1 can be repeatedly rotationally vibrated efficiently.

  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.

  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 19 and the upper electrode 21 of the first arm 12 shown in FIG. 2, the piezoelectric body 20 expands and contracts in the plane direction, and the first arm 12 is applied to the substrate 18. On the other hand, it bends and vibrates vertically.

  At this time, if the resonance driving voltage of the first tuning-fork type piezoelectric vibrator 3 is applied to the upper electrode 21, the second arm 13 is driven in the opposite phase to the first arm 12 by the principle of resonance. That is, as shown in FIG. 3, the first arm 12 and the second arm 13 can be flexed and vibrated in directions (arrows 32A and 32B directions) whose phases are different by 180 degrees, that is, in opposite directions. 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 34 of the first tuning-fork type piezoelectric vibrator 3. As a result, the first tuning-fork type piezoelectric vibrator 3 performs repetitive rotational vibration (torsional vibration) at a predetermined frequency around the X axis with the straight X axis passing through the vibration center 4 as the rotation axis.

  Next, the vibration energy of this repetitive rotational vibration is transmitted to the first support part 2 joined to the connecting part 34, and the torsional vibrator composed of the first support part 2 and the mirror part 1 Torsional vibration occurs in the direction of arrow 33 around the axis. As a result, the mirror unit 1 causes repetitive rotational vibration about the X 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 first monitor electrode 17 shown in FIG. 1 detects the displacement of the second arm 13 as an electric signal. At this time, as described above, the electrical signal detected by the first monitor electrode 17 has an opposite phase to the electrical signal applied to the upper electrode 21 of the first arm 12, so that the electrical signal detected by the first monitor electrode 17 is detected. If the electrical signal is input to the upper electrode 21 of the first arm 12 via the feedback circuit, the first tuning-fork type piezoelectric vibrator 3 can be driven by self-excitation. Further, if the input signal to the upper electrode 21 is controlled by the electrical signal detected by the first monitor electrode 17, it can be driven with high accuracy.

  The second tuning fork type piezoelectric vibrator 8 shown in FIG. 1 also applies the resonance driving voltage of the second tuning fork type piezoelectric vibrator 8 between the lower electrode and the upper electrode of the fourth arm 15, and the third arm. The torsional vibration is caused about the Y axis passing through the vibration center 9 by causing the 14 and the fourth arm 15 to bend and vibrate in directions different in phase by 180 degrees.

  When this vibration energy propagates to the third support portion 7 via the connecting portion 35, the torsional vibrator composed of the third support portion 7 and the frame body 6 is moved around the Y axis to the second tuning fork. It can be repeatedly rotated and oscillated in the opposite phase to the 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.

  The second monitor electrode 22 detects the displacement of the third arm 14 as an electric signal. At this time, if the electric signal detected by the second monitor electrode 22 is input to the upper electrode on the fourth arm 15 via the feedback circuit as described above, the second tuning-fork type piezoelectric vibrator 8 is automatically moved. It can be driven. Further, if the input signal to the fourth arm 15 is controlled by the electric signal detected by the second monitor electrode 22, it can be driven with high accuracy.

  The optical reflecting element can be applied to an image projection apparatus as shown in FIG. That is, light is incident from a light source 36 such as a laser light source or an LED light source on the mirror unit 1 that vibrates in the biaxial direction. Can be projected. In addition, it can be used for a laser exposure machine.

  In the present embodiment, light is scanned in the horizontal direction by driving by the first tuning-fork type piezoelectric vibrator 3 in FIG. 1, and light is scanned in the vertical direction by driving by the second tuning-fork type piezoelectric vibrator 8 in FIG. .

  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 0.5 mm to be the base material 18 is prepared, and a lower electrode 19 made of a platinum electrode is formed thereon using a thin film process such as sputtering or vapor deposition. The base material 18 is preferably made of a material having elasticity, mechanical strength and high Young's modulus such as metal, glass or ceramic substrate from the viewpoint of productivity. For example, the base material 18 is made of metal, crystal, glass, quartz or It is preferable to use a ceramic material from the viewpoint of mechanical properties and availability. 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.

  Thereafter, the piezoelectric body 20 is formed on the lower electrode 19 by sputtering or the like using a piezoelectric material having a high piezoelectric constant such as lead zirconate titanate (PZT). At this time, it is preferable to use an oxide dielectric containing Pb and Ti as an orientation control layer between the piezoelectric body 20 and the lower electrode 19, and orientation control composed of titanic acid, magnese, lanthanum, and lead (PLMT). It is more preferable to form a layer. Thereby, the crystal orientation of the piezoelectric body 20 is further increased, and the piezoelectric actuator 16 having excellent piezoelectric characteristics can be realized.

  Next, the upper electrode 21 made of titanium (Ti) / gold (Au), the first monitor electrode 17 and the second monitor electrode 22 are formed on the piezoelectric body 20.

  At this time, titanium below the upper electrode 21, the first monitor electrode 17, and the second monitor electrode 22 is formed to increase the adhesion with the piezoelectric body 20 such as a PZT thin film. A metal such as can be used. As a result, a bonding layer as a laminated body is enhanced because it has excellent adhesion to the piezoelectric body 20 and forms a strong diffusion layer with the gold electrode.

  In this embodiment, the thickness of the platinum lower electrode 19 is 0.2 μm, the piezoelectric body 20 made of PZT is 3.5 μm, the upper electrode 21, the first monitor electrode 17, and the titanium of the second monitor electrode 22. The portion is 0.01 μm, and the gold electrode portion is 0.3 μm.

  Next, the lower electrode 19, the piezoelectric body 20, the upper electrode 21, the first monitor electrode 17, and the second monitor electrode 22 are etched using a photolithographic technique to form a pattern.

  At this time, as an etching solution for the upper electrode 21, the first monitor electrode 17, and the second monitor electrode 22, an etching solution comprising an iodine / potassium iodide mixed solution, ammonium hydroxide, and hydrogen peroxide mixed solution is used. The electrode pattern was formed.

  Further, as an etching method used for the lower electrode 19 and the piezoelectric body 20, 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 body 20 is patterned by wet etching using a mixed solution of hydrofluoric acid, nitric acid, acetic acid and hydrogen peroxide, and then the lower electrode 19 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 patterning to form a base material 18 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 unit 1, the first support unit 2, the first tuning fork-shaped piezoelectric vibrator 3, the second support unit 5, the frame 6, the third support unit 7, the second tuning fork. The piezoelectric resonator 8, the fourth support portion 10, and the base material 18 of the support body 11 can be integrally formed from the same base material 18, realizing an optical reflective element excellent in vibration characteristics and productivity. can do.

  In addition, the optical reflecting element in the present embodiment can be manufactured at once with high accuracy by applying a semiconductor process such as a thin film process or a photolithographic technique on the base material 18 such as a silicon wafer. 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 18, but a gold or aluminum metal thin film excellent in light reflection characteristics can also be formed as a mirror film. In the present embodiment, since gold is used for the upper electrode 21, the first monitor electrode 17, and the second monitor electrode 22, this gold film can be used as it is as a mirror film, and the production efficiency is increased.

  The effect of this embodiment will be described below.

  In the present embodiment, the driving accuracy of the optical reflecting element can be increased.

  The reason is that the amplitude generated in the first tuning-fork type piezoelectric vibrator 3 can be detected by the first monitor electrode 17, and the amplitude generated in the second tuning-fork type piezoelectric vibrator 8 is detected as the second monitor electrode. This is because it can be detected at 22.

  That is, when the piezoelectric vibrator has a different shape due to a design error or the like, or an external environmental factor changes, the output driving force also fluctuates. Therefore, a desired driving force may not be obtained even when a predetermined electric signal is applied. In particular, when the piezoelectric vibrator is driven to resonate, the vibration frequency inherent to the piezoelectric vibrator changes due to a slight difference in shape, and the piezoelectric vibrator may not be driven even if an electric signal having a predetermined frequency is input.

  In contrast, in the present embodiment, the first monitor electrode 17 can detect the displacement of the second arm 13, that is, the first tuning-fork type piezoelectric vibrator 3, as an electrical signal.

  Here, since the vibration of the first tuning fork type piezoelectric vibrator 3 and the mirror unit 1 are interlocked, if the driving of the first tuning fork type piezoelectric vibrator 3 is known, the first tuning fork type piezoelectric vibrator 3 rotates about the X axis of the mirror unit 1. You will also see the drive. Therefore, if the signal from the first monitor electrode 17 is detected and the electric signal input to the first arm 12 is controlled, the first tuning-fork type piezoelectric vibrator 3 can be driven to be displaced as desired. As a result, the mirror unit 1 can also be driven in a desired manner. As a result, the driving accuracy of the optical reflecting element can be increased.

  Similarly, in the present embodiment, the displacement of the third arm 14 can be detected by the second monitor electrode 22. If the driving of the second tuning-fork type piezoelectric vibrator 8 is known, the displacement of the frame 6 and the mirror portion 1 that rotates about the Y axis can also be known.

  Therefore, if a signal from the second monitor electrode 22 is detected and an electric signal input to the piezoelectric actuator 16 of the fourth arm 15 is controlled, the second tuning-fork-type piezoelectric vibrator 8 and the frame 6 and the mirror portion are controlled. 1 can be driven by a desired displacement. As a result, the driving accuracy of the optical reflection element can be increased.

  In the present embodiment, the driving of the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8 is detected by the first monitor electrode 17 and the second monitor electrode 22, respectively. By providing the monitor electrode on at least one of them, it is possible to drive the tuning fork type piezoelectric vibrator on which the monitor electrode is provided with high accuracy, which contributes to improvement of the driving accuracy of the optical reflecting element.

  In the present embodiment, since both the first tuning-fork type piezoelectric vibrator 3 and the second tuning-fork type piezoelectric vibrator 8 are driven to resonate, either the first arm 12 or the second arm 13 is used. If the piezoelectric actuator 16 is arranged on one side and either the third arm 14 or the fourth arm 15, the other arm can be driven to resonate. Therefore, if a monitor electrode is disposed on the other arm, driving can be monitored by effectively utilizing the space of the element.

  Further, since the first arm 12, the second arm 13, the third arm 14, and the fourth arm 15 are driven in opposite phases, if a monitor electrode is arranged on either one, detection is made from this monitor electrode. An electric signal can be input to the other arm, and the element can be self-excited.

  For example, when the piezoelectric actuator 16 is disposed on the first arm 12 of one first tuning-fork type piezoelectric vibrator 3 and the first monitor electrode 17 is disposed on the other first arm 12, the output signal And the input signal have the same phase. Therefore, in this case, the electric signal detected by the first monitor electrode 17 is inverted, and then input to the piezoelectric actuator 16 of the second arm 13 to be driven by self-excitation.

  Furthermore, in the present embodiment, the first tuning-fork type piezoelectric vibrator 3 to be paired is provided with the first monitor electrodes 17 on the arms facing each other, that is, at positions where the displacement driving is performed with the same phase. (29 in FIG. 2) can be merged on the element. Therefore, for example, if the merging is performed on the frame body 6, the number of wirings routed to the minute third support portion 7 and the fourth support portion 10 can be reduced, which contributes to improvement in productivity. Furthermore, when the number of wirings is reduced, these wiring spaces can be secured and the electrical insulation between the wirings can be improved.

  For the same reason, the wiring 30 of the upper electrode 21 of the first arm 12 also flows in the same phase, so that the paired wirings 30 can be merged, for example, on the frame 6 to improve productivity. This contributes to improving the electrical insulation between the wiring.

  Note that the wiring of the second monitor electrode 22 and the wiring 31 of the upper electrode of the fourth arm 15 can also be merged on the paired wiring and the element. If the electrical signals are merged and drawn, the S / N ratio can be increased.

  Furthermore, in this embodiment, the optical reflecting element can be reduced in size.

  That is, by using the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8, the first arm 12, the second arm 13, the third arm 14, and the fourth arm 15, respectively. This is because it is possible to repeatedly rotate and vibrate the mirror unit 1 by using the bending vibration of the above.

  Therefore, for example, the mirror unit 1 can be excited without using a magnet having a large arrangement area, such as an electromagnetically driven optical reflecting element, 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.

  Moreover, in this Embodiment, since the 1st, 2nd, 3rd, 4th arm 12-15 is each linear shape, a process is also easy.

  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 first monitor electrode 17 is formed on the second arm 13, but is formed on the first arm 12, and the piezoelectric actuator 16 is formed on the second arm 13. Also good. The second monitor electrode 22 is formed on the third arm 14, but may be formed on the fourth arm 15, and the piezoelectric actuator 16 may be formed on the fourth arm 15.

  Moreover, in the said embodiment, although all the 1st support part 2, the 2nd support part 5, the 3rd support part 7, and the 4th support part 10 were made into the rod shape, for example, as shown in FIG. It may be a meander shape. Thus, by making a support part into a meander type | mold, resonator length can be lengthened and a displacement amount can be enlarged. In particular, if the third support portion 7 and the fourth support portion 10 are of a meander shape, the resonance frequency of the second tuning fork type piezoelectric vibrator 8 can be increased. Therefore, the vibration frequency ratio between the vertical direction and the horizontal direction can be increased, and a highly accurate image can be projected.

(Embodiment 2)
The difference between the present embodiment and the first embodiment is that, as shown in FIG. 6, the piezoelectric actuator 16 includes a first tuning fork type piezoelectric vibrator 3 that forms a pair and a second tuning fork type piezoelectric vibrator that forms a pair. The first and second monitor electrodes 17 and 22 are arranged on either one of the first and second tuning-fork type piezoelectric vibrators 3 and 8, respectively.

  In the present embodiment, a piezoelectric actuator 16 is formed on the first arm 12 of one first tuning-fork type piezoelectric vibrator 3, and the second arm 13 of the other first tuning-fork type piezoelectric vibrator 3 is formed. A first monitor electrode 17 was formed.

  A second monitor electrode 22 is formed on the third arm 14 of one second tuning-fork type piezoelectric vibrator 8, and a piezoelectric actuator 16 is provided on the fourth arm 15 of the other second tuning-fork type piezoelectric vibrator 8. Formed.

  In the present embodiment, first, one of the first arms 12 provided with the piezoelectric actuator 16 is driven to resonate, whereby this vibration propagates to the adjacent second arm 13 via the connecting portion 34, The arm 13 can be driven in the opposite phase.

  The vibration energy of the one first tuning fork type piezoelectric vibrator 3 propagates to the other first tuning fork type piezoelectric vibrator 3 via the first support part 2 and the mirror part 1. The other first tuning-fork type piezoelectric vibrator 3 can be similarly driven to resonate.

  As described above, in this embodiment, the piezoelectric actuator 16 is provided on one of the first tuning fork-shaped piezoelectric vibrators 3 and the first monitor electrode 17 is provided on the other, so that these wirings are different from each other. The support portion 5, the third support portion 7, and the fourth support portion 10 can be routed to each other, so that productivity can be maintained even when the element is downsized and electrical insulation between wirings is improved. It can be made.

  The second tuning fork type piezoelectric vibrator 8 also drives the resonance of one of the fourth arms 15 to drive the four arms of the pair of second tuning fork type piezoelectric vibrators 8 in resonance.

  Since the piezoelectric actuator 16 is provided on one of the pair of second tuning-fork type piezoelectric vibrators 8 and the second monitor electrode 22 is provided on the other, the number of wires can be reduced, and the wiring can be easily routed. In addition, the wiring space can be expanded and the electrical insulation between the wirings can be improved.

  Furthermore, in this embodiment, the piezoelectric actuators 16 are each formed in an L shape. In other words, in the present embodiment, the piezoelectric actuator 16 is extended to the connecting portions 34 and 35 and is formed widely up to the vibration centers 4 and 9. Since the area of the piezoelectric actuator 16 is thus increased, the driving force is increased, and the four arms can be efficiently driven by the single piezoelectric actuator 16. In addition, since the first monitor electrode 17 and the second monitor electrode 22 are also formed in an L shape, the area can be effectively used and the detection can be performed efficiently.

  The arrangement of the piezoelectric actuator 16, the first monitor electrode 17, and the second monitor electrode 22 is not limited to this form. For example, only the first tuning-fork type piezoelectric vibrator 3 is the same as in the first embodiment. The monitor electrode 17 and the piezoelectric actuator 16 are arranged in pairs, and the second tuning fork type piezoelectric vibrator 8 may be arranged with the second monitor electrode 22 and the piezoelectric actuator 16 one by one as in the present embodiment. Good.

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

(Embodiment 3)
The difference between the present embodiment and the first embodiment is the number and location of the piezoelectric actuator 16 and the first and second monitor electrodes 17 and 22.

  That is, in the present embodiment, as shown in FIG. 7, one of the pair of first tuning fork type piezoelectric vibrators 3 is formed with a piezoelectric actuator 16 on the first arm 12 as in the first embodiment. The first monitor electrode 17 is formed on the second arm 13. However, the other first tuning-fork type piezoelectric vibrator 3 has piezoelectric actuators 16 formed on the first and second arms 12 and 13, respectively.

  One of the pair of second tuning fork type piezoelectric vibrators 8 has a second monitor electrode 22 formed on the third arm 14 and a piezoelectric element on the fourth arm 15 as in the first embodiment. An actuator 16 is formed. However, the other second tuning-fork type piezoelectric vibrator 8 has piezoelectric actuators 16 formed on the third and fourth arms 14 and 15, respectively.

  The driving method of this embodiment will be described below.

  That is, in the present embodiment, the first tuning fork-shaped piezoelectric vibrator 3 in which the piezoelectric actuator 16 is formed on either the first arm 12 or the second arm 13 includes the first arm 12 and the second arm 12. If electrical signals having opposite phases are applied to the arms 13, the first arm 12 and the second arm 13 can be flexed and vibrated in directions different by 180 degrees. The driving method of the first tuning-fork type piezoelectric vibrator 3 in which the piezoelectric actuator 16 is formed on the first arm 12 and the first monitor electrode 17 is formed on the second arm 13 is the same as in the first embodiment. It is.

  Further, in the present embodiment, the third arm 14 and the fourth arm 15 are included in the second tuning-fork type piezoelectric vibrator 8 in which the piezoelectric actuator 16 is formed on each of the third arm 14 and the fourth arm 15. It is only necessary to apply electric signals having opposite phases to each other.

  The method for driving the second tuning-fork type piezoelectric vibrator 8 in which the second monitor electrode 22 is formed on the third arm 14 and the piezoelectric actuator 16 is formed on the fourth arm 15 is the same as in the first embodiment. It is.

  Also in the present embodiment, the optical reflecting element can be driven with high accuracy as in the first embodiment.

  Further, each of the first tuning fork type piezoelectric vibrator 3 and the second tuning fork type piezoelectric vibrator 8 can be provided with three piezoelectric actuators 16 and can obtain a large driving force as compared with the first embodiment. I can do it.

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

  INDUSTRIAL APPLICABILITY The present invention has an effect that the optical reflecting element can be miniaturized, and for example, a small display device that can also be used for a mobile phone terminal, a vehicle-mounted head-up display device, an electrophotographic copying machine, a laser printer, and an optical scanner. Useful for applications.

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 figure which shows the principle of the image projector using the optical reflection element The top view of the optical reflective element of another example in Embodiment 1 of this invention 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 Plan view of a conventional optical reflecting element

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 Piezoelectric actuator 17 First monitor electrode 18 Base material 19 Lower electrode 20 Piezoelectric body 21 Upper electrode 22 First Second monitor electrode 23 to 27 Connection terminal 28 Connection terminal 29 Wiring 30 Wiring 31 Wiring 32A, 32B Arrow 33 Arrow 34 Connecting portion 35 Connecting portion 36 Light source 37 Screen

Claims (7)

A pair of first tuning-fork type piezoelectric vibrators that face each other through the mirror part and are connected to the mirror part by a first support part, and these first tuning-fork type piezoelectric vibrations A frame that is connected to the vibration center of each child by a second support and surrounds the outer periphery of the pair of first tuning fork-shaped piezoelectric vibrators, is opposed to the frame through the frame, and A pair of second tuning fork-type piezoelectric vibrators connected by three support portions and having a rotation axis perpendicular to the rotation axis of the first tuning-fork type piezoelectric vibrator, and these second tuning-fork type piezoelectric vibrations A vibration center of the child and a support body respectively connected by a fourth support portion;
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, and each of the second tuning fork type piezoelectric vibrators is provided with the third tuning fork type piezoelectric vibrator. A third arm and a fourth arm on both sides of the support portion of the
At least one of the pair of first tuning-fork type piezoelectric vibrators is an optical reflecting element having a first monitor electrode on the first arm or the second arm. The first monitor electrode is formed on either the first arm or the second arm,
The optical reflective element according to claim 1, wherein a piezoelectric actuator is formed on the other side. 2. The optical reflecting element according to claim 1, wherein the first monitor electrode is formed on the opposing first arm or the opposing second arm. 3. A pair of first tuning-fork type piezoelectric vibrators that face each other through the mirror part and are connected to the mirror part by a first support part, and these first tuning-fork type piezoelectric vibrations A frame that is connected to the vibration center of each child by a second support and surrounds the outer periphery of the pair of first tuning fork-shaped piezoelectric vibrators, is opposed to the frame through the frame, and A pair of second tuning fork-type piezoelectric vibrators connected by three support portions and having a rotation axis perpendicular to the rotation axis of the first tuning-fork type piezoelectric vibrator, and these second tuning-fork type piezoelectric vibrations A vibration center of the child and a support body respectively connected by a fourth support portion;
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, and each of the second tuning fork type piezoelectric vibrators is provided with the third tuning fork type piezoelectric vibrator. A third arm and a fourth arm on both sides of the support portion of the
At least one of the second tuning-fork type piezoelectric vibrators of the pair is an optical reflecting element having a second monitor electrode on the third arm or the fourth arm. The second monitor electrode is formed on either the third arm or the fourth arm,
The optical reflection element according to claim 4, wherein a piezoelectric actuator is formed on the other side. The optical reflection element according to claim 4, wherein the second monitor electrode is formed on the third arm facing or the fourth arm facing each other. 5. The optical reflecting element according to claim 4, wherein at least one of the pair of first tuning-fork type piezoelectric vibrators has a first monitor electrode on the first arm or the second arm.

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