JP5853933B2 - Optical scanning apparatus and manufacturing method - Google Patents

Description

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

In recent years, various optical scanning devices using MEMS (Micro Electro Mechanical System) technology have been proposed for the purpose of downsizing the optical scanning device.
In contrast, the applicant of the present application provides a third frame having a reflective surface formed on the surface, a second frame provided with a predetermined gap with respect to the third frame, and a predetermined gap with respect to the second frame. And a 0th frame provided with a predetermined gap with respect to the first frame, and the third frame, the second frame, and the first frame are respectively connected to the respective rotation shafts. An optical scanning device having a three-degree-of-freedom coupled vibration system has been proposed (see, for example, Patent Document 1).

  In the optical scanning device configured as described above, the three-degree-of-freedom torsional vibrator can be brought into a resonance state by applying an inherent periodic excitation force to the first frame. Then, by superimposing periodic excitation forces corresponding to the vibrations of the second frame and the third frame, the second frame and the third frame are vibrated at different frequencies and amplitudes, respectively. The light can be scanned two-dimensionally by reflecting the light on the reflecting surface.

  By the way, a piezoelectric actuator can be used as a drive unit for applying a periodic excitation force unique to the first frame. This piezoelectric actuator is configured by laminating a drive layer formed by sandwiching a piezoelectric film layer between a first electrode layer and a second electrode layer, and a support layer that supports the drive layer. The displacement can be increased in proportion to the length (see, for example, Patent Document 2).

JP 2008-129068 A JP 2008-40240 A

  However, if the piezoelectric actuator used as the drive unit of the optical scanning device is lengthened, the area of the optical scanning device increases, and the advantage of using the MEMS technology may be impaired. In contrast, by thinning the support layer, the displacement of the piezoelectric actuator can be increased without lengthening the piezoelectric actuator.

  However, when the above-described piezoelectric actuator is used in the optical scanning device described in Patent Document 1, an elastically deformable member serving as a rotating shaft that supports the first frame so as to be torsionally vibrated and a support layer of the piezoelectric actuator are made of silicon. It is necessary to form using a substrate. That is, when the support layer of the piezoelectric actuator is thinned, the elastic deformation member is similarly thinned. When the elastic deformation member becomes thin, the processing error of the thickness of the elastic deformation member generally increases. As a result, the resonance frequency of the optical scanning device may be greatly deviated from the design value, and desired scanning characteristics may not be obtained. This is because the resonance frequency of the three-degree-of-freedom torsional vibrator changes according to the spring constant of the elastic deformation member, and this spring constant depends on the thickness of the elastic deformation member.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a technique capable of increasing the displacement of a piezoelectric actuator without reducing the thickness.

An optical scanning device made to achieve the above object includes a reflecting portion having a reflecting surface for reflecting a light beam, and a first elastic deformation member serving as a first rotation shaft for twisting and vibrating the reflecting portion, The optical scanning device scans the light beam reflected by the reflecting surface by swinging the reflecting portion around the first rotation axis.

  By the way, the resonance frequency f in the case where the reflecting portion is torsionally vibrated with the first elastic deformation member as the rotation axis is expressed by the following expression (1).

In Equation (1), k is the spring constant of the first elastic deformation member, and J is the moment of inertia of the reflecting portion.

  And the spring constant k of a 1st elastic deformation member is represented by the following Formula (2).

In Equation (2), β is a coefficient determined from the shape of the cross section of the first elastic deformation member. Further, a is the length of the long side of the cross section of the first elastic deformation member. Moreover, b is the length of the short side of the cross section of the first elastic deformation member. E is Young's modulus (lateral elastic modulus). Further, ν is a Poisson's ratio. L is the length of the first elastic deformation member.

  Therefore, when the first elastic deformable member is thinned (that is, when the length b of the short side of the cross section of the first elastic deformable member is reduced), the spring constant k of the first elastic deformable member is decreased, thereby the resonance frequency f. Decreases.

Also in the optical scanning apparatus, drive unit, a drive layer which is sandwiched therebetween formed between the piezoelectric film layer first electrode layer and the second electrode layer and a support layer for supporting the driving layer, the first rotating The driving unit is configured to be laminated along a direction perpendicular to the axis, and one end of the driving unit is fixed as a fixed end, and a voltage is applied between the first electrode layer and the second electrode layer. And the other end is displaced as a free end.

  The displacement δ of the drive unit when the voltage V is applied is expressed by the following expression (3).

In Equation (3), ts is the thickness of the support layer, tp is the thickness of the piezoelectric film layer, Ys is the Young's modulus of the support layer, Yp is the Young's modulus of the piezoelectric film layer, and l is from the fixed end of the piezoelectric unimorph 4. It is the length along the direction toward the free end. The piezoelectric constant d31, which is one of the physical properties of the piezoelectric body, is a value indicating the ease of expansion and contraction along the electrode facing surface when a voltage is applied to the piezoelectric body. It is known that the value of the constant d31 increases.

  Therefore, the displacement δ of the drive unit can be increased as the thickness ts of the support layer is decreased. That is, reducing the thickness of the support layer is equivalent to lowering the bending rigidity in the direction in which the support layer and the drive layer are stacked (hereinafter referred to as the stacking direction).

In the optical scanning device, the support layer is formed with a plurality of recesses whose depth is the same as the thickness of the support layer. Thus, by providing a plurality of recesses in the support layer, the bending rigidity of the support layer in the stacking direction can be lowered. Thereby, the displacement of a drive part can be enlarged, without making a support layer thin.

Further, in the manufacturing method, in a first forming step, a recess by etching from one side of the first silicon substrate, in Formulation step, in one surface side of the first silicon substrate, a first The silicon substrate and the second silicon substrate are bonded to each other, a drive unit is formed on the other surface side of the first silicon substrate in the second forming step, and etching is performed from the other surface side of the first silicon substrate in the third forming step. Thus, the reflecting portion and the first elastic deformation member are formed, and in the fourth forming step, the surface where the first silicon substrate and the second silicon substrate are bonded is used as the bonding surface, and the bonding surface of the second silicon substrate Etching from the opposite surface side forms a space in which the reflective portion can vibrate and vibrate.

In the thus configured manufacturing method for an optical scanning device, it is possible to manufacture an optical scanning device with a drive which recess is formed, the same effect as the optical scanning device.

1 is a plan view showing a configuration of an optical scanning device 1. FIG. It is the side view and bottom view of piezoelectric unimorph 4x of 1st Embodiment. It is sectional drawing which shows the first half part of the manufacturing process of the optical scanning device 1 of 1st Embodiment. It is sectional drawing which shows the latter half part of the manufacturing process of the optical scanning device 1 of 1st Embodiment. It is a bottom view of piezoelectric unimorph 4x of a 2nd embodiment. It is a top view which shows the notch NC generate | occur | produced by the piezoelectric unimorph 4x. It is a bottom view of piezoelectric unimorph 4x of a 3rd embodiment. It is a graph which shows the relationship between displacement (delta) and (L2 / L3). It is a figure explaining displacement (delta) in the point Pa. It is a figure explaining displacement (delta) in the point Pb. It is a bottom view of piezoelectric unimorph 4x of a 4th embodiment. It is the side view and bottom view of piezoelectric unimorph 4x of 5th Embodiment. It is sectional drawing of the optical scanning device 1 in 6th Embodiment, and the bottom view of the mirror 13. It is a bottom view of piezoelectric unimorph 4x of another embodiment about a 2nd embodiment. It is a bottom view of piezoelectric unimorph 4x of another embodiment about a 3rd embodiment. It is a bottom view of piezoelectric unimorph 4x of another embodiment about a 4th embodiment. It is the top view and side view of piezoelectric unimorph 4x of another embodiment regarding 4th Embodiment. It is a bottom view of piezoelectric unimorph 4x of another embodiment about a 5th embodiment. 2 is a plan view showing a configuration of an optical scanning device 401. FIG.

(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the optical scanning device 1 includes a light beam scanning unit 2 that scans a light beam, a support unit 3 that supports the light beam scanning unit 2, and a drive unit 4 that rotationally drives the light beam scanning unit 2. With.

The light beam scanning unit 2 includes an outer gimbal 11, an inner gimbal 12, a mirror 13, elastic connecting portions 14a and 14b, elastic connecting portions 15a and 15b, and elastic connecting portions 16a and 16b.
Among these, the mirror 13 has a circular shape, and a mirror surface portion of an aluminum thin film is formed on the surface.

The inner gimbal 12 has a rectangular frame shape, and a mirror 13 is disposed in the frame. The outer gimbal 11 has a rectangular frame shape, and the inner gimbal 12 is arranged in the frame.
The elastic connecting portion 16 a is made of an elastically deformable material, and is disposed within the frame of the inner gimbal 12 to connect the mirror 13 and the inner gimbal 12. The elastic connecting portion 16b is made of an elastically deformable material, and is disposed in the frame of the inner gimbal 12. The mirror 13 and the inner gimbal 12 are connected to the opposite side of the elastic connecting portion 16a with the mirror 13 in between. Link. The elastic connecting portion 16 a and the elastic connecting portion 16 b are arranged on the same straight line passing through the center of gravity JS of the mirror 13 and serve as the rotation axis k of the mirror 13. Thus, the mirror 13 is configured to be able to twist and vibrate about the rotation axis k.

  The elastic connecting portion 15 a is made of an elastically deformable material, and is disposed in the frame of the outer gimbal 11 to connect the inner gimbal 12 and the outer gimbal 11. The elastic connecting portion 15b is made of an elastically deformable material, and is arranged in the frame of the outer gimbal 11. The inner gimbal 12 and the outer gimbal 11 are disposed on the opposite side of the inner connecting gimbal 12 from the elastic connecting portion 15a. And The elastic connecting portion 15 a and the elastic connecting portion 15 b are arranged on the same straight line passing through the center of gravity JS of the mirror 13 and the inner gimbal 12 and serve as the rotation axis j of the mirror 13. Accordingly, the inner gimbal 12 is configured to be capable of torsional vibration about the rotation axis j.

  The elastic connecting portion 14 a is made of an elastically deformable material, and connects the upper side 11 a of the outer gimbal 11 and the support portion 3. The elastic connecting portion 14b is made of an elastically deformable material, and connects the lower side 11b of the outer gimbal 11 and the support portion 3 on the opposite side of the elastic connecting portion 14a across the outer gimbal 11. The elastic coupling portion 14 a and the elastic coupling portion 14 b are arranged on the same straight line passing through the center of gravity JS of the mirror 13, the inner gimbal 12, and the outer gimbal 11, and serve as the rotation axis i of the outer gimbal 11. Accordingly, the outer gimbal 11 is configured to be able to twist and vibrate about the rotation axis i.

  Next, the support portion 3 includes an upper support portion 3a connected to an end portion of the elastic connection portion 14a on the side not connected to the upper side 11a, and an end portion of the elastic connection portion 14b on the side not connected to the lower side 11b. The lower support portion 3b to be connected, and the left support portion 3c and the right support portion 3d that support the drive portion 4 are configured.

  Furthermore, the drive part 4 is comprised from piezoelectric unimorph 4a, 4b, 4c, 4d. The piezoelectric unimorphs 4a, 4b, 4c, 4d are formed in a rectangular plate shape, and are arranged so that the longitudinal direction thereof is orthogonal to the rotation axis i.

  The piezoelectric unimorph 4 a has one end in the longitudinal direction fixed to the left support portion 3 c and the other end connected to the upper side 11 a of the outer gimbal 11. One end of the piezoelectric unimorph 4b in the longitudinal direction is fixed to the left support 3c, and the other end is connected to the lower side 11b of the outer gimbal 11. One end of the piezoelectric unimorph 4c in the longitudinal direction is fixed to the right support 3d, and the other end is connected to the upper side 11a of the outer gimbal 11. One end of the piezoelectric unimorph 4 d in the longitudinal direction is fixed to the right support portion 3 d and the other end is connected to the lower side 11 b of the outer gimbal 11.

  Accordingly, when a voltage is applied to the piezoelectric unimorphs 4a, 4b, 4c, and 4d, the end portion on the side connected to the outer gimbal 11 is bent and displaced, and the piezoelectric unimorphs 4a, 4b, 4c, and 4d are rotated along the rotation axis i. Thus, the outer gimbal 11 can be moved.

  The piezoelectric unimorph 4a and the piezoelectric unimorph 4b bend and vibrate in the same phase, the piezoelectric unimorph 4c and the piezoelectric unimorph 4d bend and vibrate in the same phase, and the piezoelectric unimorphs 4a and 4b and the piezoelectric unimorphs 4c and 4d are reversed. Voltage application to the piezoelectric unimorphs 4a, 4b, 4c, and 4d is controlled so as to bend and vibrate in phase. As a result, the outer gimbal 11 rotates and vibrates around the rotation axis i. Then, by vibrating the outer gimbal 11 at a predetermined resonance frequency, the light beam reflected by the mirror 13 can be two-dimensionally scanned based on the operating principle described below.

Next, the operation principle of the optical scanning device 1 will be described.
The optical scanning device 1 is a three-degree-of-freedom torsional vibrator having a degree of freedom of twisting with respect to the rotation axes i, j, and k with the support portion 3 as a fixed end.

  A three-degree-of-freedom torsional vibrator theoretically has three vibration modes. That is, the three vibration modes have different resonance frequencies, and the ratio of the angular amplitude of the torsional vibration of each frame to each resonance frequency is different (this is called a vibration mode). Hereinafter, these three vibration modes are referred to as vibration mode 1, vibration mode 2, and vibration mode 3, respectively.

  If a periodic excitation force having a frequency corresponding to each of vibration mode 1, vibration mode 2, and vibration mode 3 is applied, the respective vibration modes can be excited. In addition, if a plurality of periodic excitation forces with a plurality of frequencies are superimposed and applied, a plurality of vibration modes can be excited simultaneously.

Here, for example,
The resonance frequency f1 of vibration mode 1 is 1000 Hz,
The resonance frequency f2 of vibration mode 2 is 5000 Hz,
The resonance frequency f3 of vibration mode 3 is 40000 Hz,
The amplitude ratio r1 of the outer gimbal 11, the inner gimbal 12, and the mirror 13 in the vibration mode 1 is “1: −20: 0.5”,
The amplitude ratio r2 of the outer gimbal 11, the inner gimbal 12, and the mirror 13 in the vibration mode 2 is set to “1: 0.5: −0.1”,
The amplitude ratio r3 of the outer gimbal 11, the inner gimbal 12, and the mirror 13 in the vibration mode 3 is “1: 0.01: −30”,
The operation of the three-degree-of-freedom torsional vibrator will be described.

  The amplitude ratio in each vibration mode is described in the order of the outer gimbal 11, the inner gimbal 12, and the mirror 13 from the left. For example, when the amplitude of the outer gimbal 11 is “1”, the amplitude ratio r1 indicates that the amplitude of the inner gimbal 12 is “−20” and the amplitude of the mirror 13 is “0.5”.

  In the resonance state of the three-degree-of-freedom torsional vibrator, the phase angle between the frames is theoretically 0 degree or 180 degrees. Therefore, when describing the amplitude ratio, the sign is “+” when the phase angle difference is 0 degree, and the sign is “−” when the difference is 180 degrees. For example, the amplitude ratio r1 indicates that the phase angle difference between the outer gimbal 11 and the mirror 13 is 0 degree, and the phase angle difference between the outer gimbal 11 and the inner gimbal 12 is 180 degrees.

  When the resonance frequency and amplitude ratio of each vibration mode are designed as described above, in the vibration mode 1, the inner gimbal 12 is largely torsionally vibrated at 1000 Hz. In the vibration mode 3, the mirror 13 mainly vibrates at 40,000 Hz.

  For this reason, the laser beam is reflected by the mirror surface portion of the mirror 13 and the vibration mode 1 and the vibration mode 3 are simultaneously excited, so that the vibration mode 3 is in the main scanning direction (40000 Hz) and the vibration mode 1 is in the sub-scanning direction ( 1000 Hz), the laser beam can be scanned two-dimensionally.

  Next, the structure of the piezoelectric unimorphs 4a, 4b, 4c, 4d will be described. Hereinafter, one piezoelectric unimorph representing the piezoelectric unimorphs 4a, 4b, 4c, and 4d is referred to as a piezoelectric unimorph 4x.

2A is a side view of the piezoelectric unimorph 4x, and FIG. 2B is a bottom view of the piezoelectric unimorph 4x. FIG. 2C is a side view showing a state in which the piezoelectric unimorph 4x is displaced.
As shown in FIG. 2A, the piezoelectric unimorph 4x includes a support layer 21 made of silicon as a material, an oxide film layer (silicon oxide in this embodiment) 22, and a piezoelectric film layer 31 (in this embodiment). The drive layer 23 formed by sandwiching lead zirconate titanate (PZT) between the upper electrode layer 32 and the lower electrode layer 33 is sequentially stacked along the stacking direction D1.

Further, as shown in FIGS. 2A and 2B, the support layer 21 is provided with a plurality of (four in this embodiment) concave portions 41, 42, 43, 44.
As shown in FIG. 2A, the recesses 41, 42, 43, and 44 penetrate the support layer 21 along the stacking direction D1. That is, the depth of the recesses 41, 42, 43, 44 is the same as the thickness of the support layer 21. Further, as shown in FIG. 2B, the recesses 41, 42, 43, and 44 penetrate the support layer 21 along the short direction D2 of the piezoelectric unimorph 4x formed in a rectangular plate shape. Accordingly, the cross-sections of the recesses 41, 42, 43, and 44 are such that the length L1 along the short direction D2 of the piezoelectric unimorph 4x (hereinafter referred to as the longitudinal length L1) is the length in the short direction D2 of the piezoelectric unimorph 4x. A rectangular shape equal to.

  The recesses 41, 42, 43, and 44 are formed so that the length L2 (hereinafter referred to as the lateral length L2) along the longitudinal direction D3 of the piezoelectric unimorph 4x is equal to each other. It arrange | positions at equal intervals along the direction D3.

  As shown in FIG. 2C, the displacement δ of the piezoelectric unimorph 4x when the voltage V is applied is expressed by the following equation (3).

In Equation (3), ts is the thickness of the support layer 21, tp is the thickness of the piezoelectric film layer 31, Ys is the Young's modulus of the support layer 21, Yp is the Young's modulus of the piezoelectric film layer 31, and l is the piezoelectric unimorph 4x. Is the length in the longitudinal direction. The piezoelectric constant d31, which is one of the physical properties of the piezoelectric body, is a value indicating the ease of expansion and contraction along the electrode facing surface when a voltage is applied to the piezoelectric body. It is known that the value of the constant d31 increases.

Next, a method for manufacturing the optical scanning device 1 will be described with reference to FIGS.
In order to manufacture the optical scanning device 1, first, as shown in FIG. 3A, a thermal oxidation process is performed on the silicon substrate 100. Thereby, the thermal oxide film 110 is formed on the surface of the silicon substrate 100 and the thermal oxide film 120 is also formed on the back surface of the silicon substrate 100.

  Then, as shown in FIG. 3B, trenches 121 are formed in the portions where the recesses 41, 42, 43, 44 are formed on the back surface side of the silicon substrate 100. The trench 121 penetrates the thermal oxide film 120 and the silicon substrate 100.

  Next, as shown in FIG. 3C, the thermal oxide film 120 on the back side of the silicon substrate 100 is brought into contact with the surface of the silicon substrate 140 on which the thermal oxide film 130 is formed on the back side. The substrate 140 is bonded to the silicon substrate 100.

  Then, a Ti / Pt layer 150 is deposited on the thermal oxide film 110, a PZT layer 160 is further deposited on the Ti / Pt layer 150, and then patterned. As a result, as shown in FIG. 3D, the piezoelectric film layer 31 and the lower electrode layer 33 of the piezoelectric unimorph 4x are formed above the trench 121.

  Further, a Ti / Au layer 170 is deposited and patterned. Thereby, as shown in FIG. 3E, the upper electrode layer 32 of the piezoelectric unimorph 4x and the mirror surface portion 175 of the mirror 13 are formed.

  Then, as shown in FIG. 3 (f), the silicon in the region corresponding to the gap of the optical scanning device 1 (in FIG. 3 (f), the gap between the elastic coupling portion 14a or the elastic coupling portion 14b and the piezoelectric unimorph 4x). The substrate 100 and the thermal oxide film 110 are etched by DRIE.

  Thereafter, as shown in FIG. 4A, regions corresponding to the light beam scanning unit 2 and the driving unit 4 in the thermal oxide film 130 on the back surface of the silicon substrate 140 are removed by etching, and then the heat that has not been removed is removed. By etching the silicon substrate 140 using the oxide film 130 as a mask, a recess 180 is formed in the silicon substrate 140.

  Further, as shown in FIG. 4B, the region of the recess 180 in the thermal oxide film 120 and the thermal oxide film 130 on the back surface of the silicon substrate 140 are removed by etching. Thus, the optical scanning device 1 is configured so that the light beam scanning unit 2 can rotate, and the concave portions 41, 42, 43, and 44 are formed in the piezoelectric unimorph 4x.

  The optical scanning device 1 configured as described above includes a mirror 13 having a reflecting surface for reflecting a light beam, elastic coupling portions 16a and 16b serving as a rotation axis k for torsionally vibrating the mirror 13, and a rotation axis k. A piezoelectric unimorph 4x that generates a driving force for torsionally oscillating the mirror 13 about the center is provided, and the light beam reflected by the reflecting surface is scanned by swinging the mirror 13 about the rotation axis k. .

  By the way, the resonance frequency f when the mirror 13 is torsionally oscillated with the elastic coupling portions 16a and 16b as the rotation axes is expressed by the following equation (1).

In equation (1), k is the spring constant of the elastic connecting portions 16a and 16b, and J is the moment of inertia of the mirror 13.

  And the spring constant k of the elastic connection parts 16a and 16b is represented by the following formula (2).

In equation (2), β is a coefficient determined from the cross-sectional shape of the elastic coupling portions 16a and 16b. Moreover, a is the length of the long side of the cross section of the elastic connection parts 16a and 16b. Moreover, b is the length of the short side of the cross section of the elastic connection parts 16a and 16b. E is Young's modulus (lateral elastic modulus). Further, ν is a Poisson's ratio. In addition, l is the length of the elastic connecting portions 16a and 16b.

  Accordingly, when the elastic connecting portions 16a and 16b are thinned (that is, when the length b of the short side of the cross section of the elastic connecting portions 16a and 16b is reduced), the spring constant k of the elastic connecting portions 16a and 16b is decreased. The resonance frequency f decreases.

  In the optical scanning device 1, the piezoelectric unimorph 4 x includes a driving layer 23 formed by sandwiching the piezoelectric film layer 31 between the upper electrode layer 32 and the lower electrode layer 33, and a support layer 21 that supports the driving layer 23. Are stacked in a direction perpendicular to the rotation axis k, and one end of the piezoelectric unimorph 4x is fixed as a fixed end, and a voltage is applied between the upper electrode layer 32 and the lower electrode layer 33. Is bent when applied, and the other end is displaced as a free end.

  The displacement δ of the piezoelectric unimorph 4x when the voltage V is applied is expressed by the following equation (3).

In Equation (3), ts is the thickness of the support layer 21, tp is the thickness of the piezoelectric film layer 31, Ys is the Young's modulus of the support layer 21, Yp is the Young's modulus of the piezoelectric film layer 31, and l is the piezoelectric unimorph 4x. It is the length along the longitudinal direction D3. The piezoelectric constant d31, which is one of the physical properties of the piezoelectric body, is a value indicating the ease of expansion and contraction along the electrode facing surface when a voltage is applied to the piezoelectric body. It is known that the value of the constant d31 increases.

  Therefore, the displacement δ of the piezoelectric unimorph 4x can be increased as the thickness ts of the support layer 21 is reduced. That is, making the support layer 21 thin is equivalent to lowering the bending rigidity in the stacking direction D1.

  In the optical scanning device 1, recesses 41, 42, 43, 44 having the same depth as the thickness of the support layer 21 are formed in the support layer 21. Thus, by providing the support layer 21 with the recesses 41, 42, 43, and 44, the bending rigidity of the support layer 21 in the stacking direction D1 can be lowered. Thereby, the displacement δ of the piezoelectric unimorph 4x can be increased without making the support layer 21 thin.

  Further, since the piezoelectric film layer 31 is made of lead zirconate titanate (PZT) having the largest piezoelectric constant d31 among the piezoelectric materials generally used, the displacement amount of the mirror 13 by the piezoelectric unimorph 4x can be increased. .

  Further, the concave portions 41, 42, 43, and 44 are formed by etching from one surface side of the silicon substrate 100 (see FIGS. 3A and 3B), and one surface side of the silicon substrate 100 is formed. Then, the silicon substrate 100 and the silicon substrate 140 are bonded together (see FIG. 3C), and the piezoelectric unimorph 4x is formed on the other surface side of the silicon substrate 100 (FIGS. 3D and 3E). The mirror 13 and the elastic coupling portions 16a and 16b are formed by etching from the other surface side of the silicon substrate 100 (see FIG. 3F), and the surface opposite to the bonding surface of the silicon substrate 140 Etching from the side forms a recess 180 in which the mirror 13 can be torsionally vibrated (see FIGS. 4A and 4B), so that the depth is equal to the thickness of the support layer 21. One recess 41, 42, 43, 44 is an optical scanning device 1 formed in the support layer 21 is manufactured. Thereby, the displacement δ of the piezoelectric unimorph 4x can be increased without making the support layer 21 thin.

  In the embodiment described above, the mirror 13 is the reflection portion in the present invention, the rotation axis k is the first rotation shaft in the present invention, and the elastic connection portions 16a and 16b are the first elastic deformation members in the present invention, the piezoelectric unimorphs 4a, 4b, Reference numerals 4c and 4d denote driving units in the present invention, the upper electrode layer 32 is a first electrode layer in the present invention, and the lower electrode layer 33 is a second electrode layer in the present invention.

  Further, the inner gimbal 12 is the first support portion in the present invention, the elastic connecting portions 15a and 15b are the second elastic deformation members in the present invention, the rotation axis j is the second rotation shaft in the present invention, and the outer gimbal 11 is the first in the present invention. 2 is a third elastic deformation member in the present invention, the rotation shaft i is a third rotation shaft in the present invention, and the support portion 3 is a third support portion in the present invention.

  Further, the process of changing the state of FIG. 3 (a) to the state of FIG. 3 (b) is the first forming step in the present invention, and the process of changing the state of FIG. 3 (b) to the state of FIG. The bonding process in FIG. 3, the process of changing the state of FIG. 3 (c) to the state of FIG. 3 (e) is the second forming process in the present invention, the process of changing the state of FIG. 3 (e) to the state of FIG. Is the third forming step in the present invention, the process of changing the state of FIG. 3 (f) to the state of FIG. 4 (b) is the fourth forming step in the present invention, and the silicon substrate 100 is the first silicon substrate and silicon substrate in the present invention. Reference numeral 140 denotes a second silicon substrate in the present invention.

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

The optical scanning device 1 in the second embodiment is the same as that in the first embodiment except that the configuration of the piezoelectric unimorph 4x is changed.
The piezoelectric unimorph 4x of the second embodiment is the same as that of the first embodiment except that recesses 51, 52, 53, and 54 are formed instead of the recesses 41, 42, 43, and 44, as shown in FIG. The same.

The recesses 51, 52, 53, and 54 are the same as the recesses 41, 42, 43, and 44 except that the length L1 in the longitudinal direction is shorter than the length in the short direction D2 of the piezoelectric unimorph 4x.
The recesses 51, 52, 53, and 54 are all arranged inside the piezoelectric unimorph 4x on all four sides forming a rectangular cross section. That is, unlike the recesses 41, 42, 43, and 44, the recesses 51, 52, 53, and 54 do not intersect the long sides of the piezoelectric unimorph 4x formed in a rectangular plate shape, and are formed in a square hole shape. Yes.

  In the optical scanning device 1 configured in this way, the lengths (longitudinal length L1) along the short direction D2 of the recesses 51, 52, 53, 54 are along the short direction D2 of the support layer 21. Shorter than length.

  As a result, when the concave portion is formed, the concave portion is displaced in the short direction D2 of the piezoelectric unimorph 4x, so that the long side of the piezoelectric unimorph 4x formed in a rectangular plate shape intersects with the concave portion as shown in FIG. It is possible to suppress the occurrence of the situation (see the broken-line rectangle in FIG. 6). For this reason, it can suppress that the area | region of the recessed part in the piezoelectric unimorph 4x reduces, and generation | occurrence | production of the notch NC in the piezoelectric unimorph 4x.

  Accordingly, it is possible to suppress the bending rigidity of the piezoelectric unimorph 4x from deviating from the design value and the displacement of the piezoelectric unimorph 4x from the design value, and it is possible to suppress the breakage starting from the notch NC.

In the embodiment described above, the longitudinal direction D3 of the piezoelectric unimorph 4x is the first direction in the present invention, and the short direction D2 of the piezoelectric unimorph 4x is the second direction in the present invention.
(Third embodiment)
A third embodiment of the present invention will be described below with reference to the drawings. In the third embodiment, parts different from the second embodiment will be described.

The optical scanning device 1 in the third embodiment is the same as that in the second embodiment except that the configuration of the piezoelectric unimorph 4x is changed.
And the piezoelectric unimorph 4x of 3rd Embodiment is the same as 2nd Embodiment except the point which the recessed parts 61 and 62 are formed instead of the recessed parts 51, 52, 53, 54, as shown in FIG.

  The recesses 61 and 62, like the recesses 51, 52, 53 and 54, have a longitudinal length L1 which is shorter than the length of the piezoelectric unimorph 4x in the short direction D2 and forms a rectangular shape in the cross section of the recesses 61 and 62. All are arranged inside the piezoelectric unimorph 4x.

The recesses 61 and 62 are arranged so that L2 is 0.8 to 0.9 times L3, where L3 is the sum of the lateral length L2 of the recesses and the interval between the adjacent recesses.
In the optical scanning device 1 configured as described above, the piezoelectric unimorph 4x can be displaced efficiently. The reason for this will be described below.

  FIG. 8 is a graph showing the relationship between the displacement δ of the piezoelectric unimorph 4x and (L2 / L3) for each thickness tp of the piezoelectric film layer 31. FIG. 8 shows a simulation result when the thickness tp of the piezoelectric film layer 31 is 1.5 μm (see the curve CL1), 3 μm (see the curve CL2), and 4.5 μm (see the curve CL3).

  As shown in FIG. 8, regardless of the thickness tp of the piezoelectric film layer 31, the displacement δ increases as (L2 / L3) increases, and the displacement occurs when (L2 / L3) is 0.8 to 09. δ is the maximum value or a size near the maximum value. Further, when (L2 / L3) exceeds 0.9, the displacement δ decreases as (L2 / L3) increases.

  FIG. 9A is an enlarged view of the curve CL1 in the graph of FIG. FIG. 9B is a perspective view of the piezoelectric unimorph 4x showing the displacement δ at the point Pa in FIG. 9A. FIG. 9C is a graph showing the relationship between the length in the longitudinal direction and the displacement δ for the piezoelectric unimorph 4x in FIG. 9B. A point Pa shown in FIG. 9A is a point at which the displacement δ is maximum.

  As shown in the perspective view of FIG. 9B and the curve CL11 of FIG. 9C, the displacement δ increases as the distance from the fixed end E1 of the piezoelectric unimorph 4x (the longitudinal length of the piezoelectric unimorph 4x) increases. The displacement δ is maximum at the free end E2.

  Further, FIG. 10A is an enlarged view of the curve CL1 in the graph of FIG. FIG. 10B is a perspective view of the piezoelectric unimorph 4x showing the displacement δ at the point Pb in FIG. FIG.10 (c) is a graph which shows the relationship between the longitudinal direction length of piezoelectric unimorph 4x, and the displacement (delta) about FIG.10 (b). Note that a point Pb shown in FIG. 10A is a point where (L2 / L3) is larger than the point Pa.

  As shown in the perspective view of FIG. 10B and the curve CL12 of FIG. 10C, the displacement δ increases as the distance from the fixed end E1 of the piezoelectric unimorph 4x (the longitudinal length of the piezoelectric unimorph 4x) increases. The displacement δ is maximum at the free end E2. However, as shown in FIG. 10C, the displacement δ at the point Pb (see the curve CL12) is smaller than the displacement δ at the point Pa (see the curve CL11). . This is because the piezoelectric unimorph 4x is greatly bent in the region where the recesses 61 and 62 are formed (see the thin film regions R1 and R2 in FIG. 10B) and is not efficiently converted into the displacement of the piezoelectric unimorph 4x.

In the embodiment described above, the recess 61 is the first recess in the present invention, and the recess 62 is the second recess in the present invention.
(Fourth embodiment)
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. In the fourth embodiment, parts different from the first embodiment will be described.

The optical scanning device 1 in the fourth embodiment is the same as that in the first embodiment except that the configuration of the piezoelectric unimorph 4x is changed.
And the piezoelectric unimorph 4x of 4th Embodiment has the recessed parts 71, 72, 73, 74, 75, 76, 77 formed in place of the recessed parts 41, 42, 43, 44 as shown in FIG. Is the same as in the first embodiment.

The recesses 71, 72, 73, 74, 75, 76, and 77 are the same as the recesses 41, 42, 43, and 44 of the first embodiment except that the arrangement is changed.
That is, as the recesses 71, 72, 73, 74, 75, 76, 77 approach the fixed end E1 of the piezoelectric unimorph 4x along the longitudinal direction D3 of the piezoelectric unimorph 4x, the interval between the adjacent recesses becomes longer. The points are the same as those of the first embodiment except that they are arranged in the first embodiment. The fixed end E1 is a short side on the side fixed to the support portion 3 among two short sides constituting the rectangle of the piezoelectric unimorph 4x.

  Specifically, first, the concave portion 71, the concave portion 72, the concave portion 73, the concave portion 74, the concave portion 75, the concave portion 76, and the concave portion 77 are arranged in the order from the fixed end E1 along the longitudinal direction D3. The distance between the recess 71 and the recess 72 is L11, the distance between the recess 72 and the recess 73 is L12, the distance between the recess 73 and the recess 74 is L13, and the distance between the recess 74 and the recess 75 is When the interval is L14, the interval between the recess 75 and the recess 76 is L15, and the interval between the recess 76 and the recess 77 is L16, the relationship of L11> L12> L13> L14> L15> L16 is established.

  In the optical scanning device 1 configured as described above, the closer the fixed end E1 is, the smaller the area where the concave portion is formed. Therefore, the closer to the fixed end E1, the bending rigidity of the support layer 21 in the stacking direction D1 becomes. Can be bigger. In order to increase the driving force of the piezoelectric unimorph 4x, it is necessary to increase the bending rigidity as it approaches the fixed end E1 of the piezoelectric unimorph 4x.

  As shown in FIG. 17A, as a method of increasing the bending rigidity as the piezoelectric unimorph 4x approaches the fixed end E1, the piezoelectric unimorph 4x increases as the distance from the fixed end E1 (the length in the longitudinal direction D3) increases. It can be considered that the length in the short direction D2 is reduced. In addition, as shown in FIG. 17B, it can be considered that the support layer 21 is formed thinner as the distance from the fixed end E1 (length in the longitudinal direction D3) becomes longer. However, in the method shown in FIG. 17A, since the length in the short direction D2 increases as the distance from the fixed end E1 increases, the area of the piezoelectric unimorph 4x increases and the cost increases. Further, in the method shown in FIG. 17B, it is necessary to perform a complicated process such as performing etching of the support layer 21 step by step, and the manufacturing cost is high and not practical.

  Therefore, in the optical scanning device 1, the displacement δ can be increased by forming the concave portion in the support layer 21 without increasing the cost, and the decrease in the driving force of the piezoelectric unimorph 4x due to the formation of the concave portion is suppressed. be able to.

(Fifth embodiment)
A fifth embodiment of the present invention will be described below with reference to the drawings. In the fifth embodiment, parts different from the first embodiment will be described.

The optical scanning device 1 in the fifth embodiment is the same as that in the first embodiment except that the configuration of the piezoelectric unimorph 4x is changed.
12A is a side view of the piezoelectric unimorph 4x, and FIG. 12B is a bottom view of the piezoelectric unimorph 4x.

  As shown in FIGS. 12A and 12B, the piezoelectric unimorph 4x of the fifth embodiment has recesses 81, 82, 83, 84, 85, 86 instead of the recesses 41, 42, 43, 44. Except for the point formed, it is the same as the first embodiment.

  The concave portions 81, 82, 83, 84, 85, 86 are the concave portions 41 of the first embodiment, except that the lateral length L 2 is increased as the distance from the fixed end E 1 of the piezoelectric unimorph 4 x increases. 42, 43, 44. The recesses 81, 82, 83, 84, 85, 86 are arranged at equal intervals along the longitudinal direction D3 of the piezoelectric unimorph 4x.

  Specifically, first, the concave portion 81, the concave portion 82, the concave portion 83, the concave portion 84, the concave portion 85, and the concave portion 86 are arranged in the order from the fixed end E1 along the longitudinal direction D3. When the lateral lengths L2 of the recesses 81, 82, 83, 84, 85, 86 are respectively lateral lengths L21, L22, L23, L24, L25, L26, L21 <L22 <L23 <L24 <L25. The relationship <L26 is established.

  In the optical scanning device 1 configured as described above, the closer the fixed end E1 is, the smaller the area where the concave portion is formed. Therefore, the closer to the fixed end E1, the bending rigidity of the support layer 21 in the stacking direction D1 becomes. Can be bigger. In order to increase the driving force of the piezoelectric unimorph 4x, it is necessary to increase the bending rigidity as it approaches the fixed end E1 of the piezoelectric unimorph 4x.

  Therefore, in the optical scanning device 1, the displacement δ can be increased by forming a recess in the support layer 21, and a decrease in the driving force of the piezoelectric unimorph 4 x due to the formation of the recess can be suppressed.

(Sixth embodiment)
A sixth embodiment of the present invention will be described below with reference to the drawings. In the sixth embodiment, parts different from the first embodiment will be described.

FIG. 13A is a sectional view of the optical scanning device 1, and FIG. 13B is a bottom view of the mirror 13.
The optical scanning device 1 in the sixth embodiment is the same as that in the first embodiment except that a rib 90 is added.

  As shown in FIGS. 13A and 13B, the rib 90 is formed in a cylindrical shape, and its cylindrical axis is opposite to the back surface of the mirror 13 (that is, the surface on which the mirror surface portion is formed). Is arranged on the back surface of the mirror 13 so as to be orthogonal to the side surface.

  In the optical scanning device 1 configured as described above, the rigidity of the mirror 13 can be increased by the rib 90. If the rigidity of the mirror 13 is small, the mirror 13 is likely to be distorted due to an initial stress at the time of manufacture and an inertial force at the time of scanning of the mirror 13. When the mirror 13 is distorted, the light beam reflected by the mirror 13 is also distorted, resulting in deterioration of an image formed by scanning the light beam.

Therefore, in the optical scanning device 1, since the rigidity of the mirror 13 can be increased by the rib 90, it is possible to suppress the deterioration of the image formed by the scanning of the light beam.
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken.

  For example, in the second embodiment, the concave portion has a rectangular shape, but a rectangular corner may be rounded as shown in FIG. Thereby, the stress concerning the corner | angular part of a recessed part can be reduced. Further, as shown in FIG. 14B, a rectangular recess may be arranged along the short direction D2 of the piezoelectric unimorph 4x. Moreover, as shown in FIG.14 (c), while setting a recessed part along the transversal direction D2 of the piezoelectric unimorph 4x, you may make it the corner | angular part of a recessed part round.

  In the third embodiment, two recesses are formed. However, as shown in FIGS. 15A and 15B, more than two recesses are formed. It may be.

Moreover, in the said 4th Embodiment, although the vertical direction length L1 of the recessed part showed what is equal to the length of the transversal direction D2 of the piezoelectric unimorph 4x, as shown to Fig.16 (a), as 2nd Embodiment and Similarly, the length L1 in the vertical direction may be shorter than the length in the short direction D2 of the piezoelectric unimorph 4x. Further, as shown in FIG. 16B, the longitudinal length L1 may be shorter than the length in the short direction D2 of the piezoelectric unimorph 4x and the corners of the rectangle may be rounded. Further, as shown in FIG. 16C, a circular recess may be arranged along the short direction D2 of the piezoelectric unimorph 4x.

Moreover, in the said 5th Embodiment, although the vertical direction length L1 of the recessed part showed what is equal to the length of the transversal direction D2 of the piezoelectric unimorph 4x, as shown to Fig.18 (a), as 2nd Embodiment and Similarly, the length L1 in the vertical direction may be shorter than the length in the short direction D2 of the piezoelectric unimorph 4x. Further, as shown in FIG. 18B, the longitudinal length L1 may be shorter than the length in the short direction D2 of the piezoelectric unimorph 4x and the corners of the rectangle may be rounded. Further, as shown in FIG. 18C, a circular or oval concave portion may be arranged along the short direction D2 of the piezoelectric unimorph 4x.

In the above embodiment, the optical scanning device 1 constituting the three-degree-of-freedom coupled vibration system is applied. However, the connecting displacement portion of the present invention may be applied to the optical scanning device described below.
As shown in FIG. 19, the optical scanning device 401 includes a light beam scanning unit 402 that scans a light beam, a support unit 403 that supports the light beam scanning unit 402, and a drive unit 404 that rotationally drives the light beam scanning unit 402. With.

The light beam scanning unit 402 includes a gimbal 411, a mirror 412, elastic coupling portions 413a and 413b, and elastic coupling portions 414a and 414b.
Among these, the mirror 412 is the same as the mirror 13 of the first embodiment.

The gimbal 411 has a rectangular frame shape, and a mirror 412 is disposed in the frame.
The elastic connecting portion 414a is made of an elastically deformable material, and is disposed within the frame of the gimbal 411, and connects the mirror 412 and the gimbal 411. The elastic connecting portion 414b is made of an elastically deformable material and is disposed within the frame of the gimbal 411, and connects the mirror 412 and the gimbal 411 on the opposite side of the elastic connecting portion 414a with the mirror 412 interposed therebetween. . The elastic connecting portion 414a and the elastic connecting portion 414b serve as the rotation axis k of the mirror 412. Thus, the mirror 412 is configured to be able to twist and vibrate about the rotation axis k.

  The elastic connecting portion 413 a is made of an elastically deformable material, and connects the upper side 411 a of the gimbal 411 and the support portion 403. The elastic connecting portion 413b is made of an elastically deformable material, and connects the lower side 411b of the gimbal 411 and the support portion 403 on the opposite side of the elastic connecting portion 413a with the gimbal 411 interposed therebetween. The elastic coupling portion 413a and the elastic coupling portion 413b serve as the rotation axis i of the gimbal 411. Thereby, the gimbal 411 is configured to be able to twist and vibrate about the rotation axis i.

  Next, the support portion 403 includes an upper support portion 403a connected to the end portion of the elastic connection portion 413a on the side not connected to the upper side 411a, and an end portion of the elastic connection portion 413b on the side not connected to the lower side 411b. The lower support part 403b to be connected, and a left support part 403c and a right support part 403d that support the drive part 4 are configured.

Furthermore, the drive part 404 is comprised from piezoelectric unimorph 404a, 404b, 404c, 404d, 404e, 404f, 404g, 404h.
The piezoelectric unimorphs 404a, 404b, 404c, 404d are formed in a rectangular plate shape, and are arranged so that the longitudinal direction thereof is orthogonal to the rotation axis i. The piezoelectric unimorph 404a has one end in the longitudinal direction fixed to the left support 403c and the other end connected to the upper side 411a of the gimbal 411. One end of the piezoelectric unimorph 404b in the longitudinal direction is fixed to the left support portion 403c, and the other end is connected to the lower side 411b of the gimbal 411. One end of the piezoelectric unimorph 404c in the longitudinal direction is fixed to the right support portion 403d, and the other end is connected to the upper side 411a of the gimbal 411. One end of the piezoelectric unimorph 404d in the longitudinal direction is fixed to the right support portion 403d, and the other end is connected to the lower side 411b of the gimbal 411.

  The piezoelectric unimorphs 404e, 404f, 404g, and 404h are formed in a rectangular plate shape, and are arranged so that the longitudinal direction thereof is orthogonal to the rotation axis k. The piezoelectric unimorph 404e has one end in the longitudinal direction fixed to the gimbal 411 and the other end connected to the elastic connecting portion 414b. The piezoelectric unimorph 404f is disposed on the opposite side of the piezoelectric unimorph 404e with the mirror 412 interposed therebetween, and one end in the longitudinal direction thereof is fixed to the gimbal 411, and the other end is connected to the elastic connecting portion 414a. The piezoelectric unimorph 404g is disposed on the opposite side of the piezoelectric unimorph 404e across the elastic coupling portion 414b, one end in the longitudinal direction thereof is fixed to the gimbal 411, and the other end is coupled to the elastic coupling portion 414b. The piezoelectric unimorph 404h is disposed on the opposite side of the piezoelectric unimorph 404f across the elastic coupling portion 414a, one end in the longitudinal direction thereof is fixed to the gimbal 411, and the other end is coupled to the elastic coupling portion 414a.

  Then, the piezoelectric unimorph 404a and the piezoelectric unimorph 404b bend and vibrate in the same phase, the piezoelectric unimorph 404c and the piezoelectric unimorph 404d bend and vibrate in the same phase, and the piezoelectric unimorphs 404a and 404b and the piezoelectric unimorphs 404c and 404d are reversed. Voltage application to the piezoelectric unimorphs 404a, 404b, 404c, and 404d is controlled so as to bend and vibrate in phase. As a result, the gimbal 411 rotates and vibrates around the rotation axis i.

  Further, the piezoelectric unimorph 404e and the piezoelectric unimorph 4f bend and vibrate in the same phase, the piezoelectric unimorph 404g and the piezoelectric unimorph 404h bend and vibrate in the same phase, and the piezoelectric unimorphs 404e and 404f and the piezoelectric unimorphs 404g and 404h are reversed. Voltage application to the piezoelectric unimorphs 404e, 404f, 404g, and 404h is controlled so as to bend and vibrate in phase. As a result, the mirror 412 rotates and vibrates around the rotation axis k.

  According to the optical scanning device 401 configured as described above, the light beam reflected by the mirror 412 is two-dimensionally scanned by swinging about the rotation axis k and swinging about the rotation axis i. be able to.

  The mirror 412 is a reflecting portion in the present invention, the elastic connecting portions 414a and 414b are first elastic deformation members in the present invention, the gimbal 411 is a first supporting portion in the present invention, and the elastic connecting portions 413a and 413b are second in the present invention. The elastically deformable member, the rotation shaft i is the second rotation shaft in the present invention, and the support portion 403 is the second support portion in the present invention.

  DESCRIPTION OF SYMBOLS 1,401 ... Optical scanning device, 4a, 4b, 4c, 4d, 404a, 404b, 404c, 404d, 404e, 404f, 404g, 404h ... Piezoelectric unimorph, 13, 412 ... Mirror, 16a, 16b, 414a, 414b ... Elasticity Connecting part, 21 ... support layer, 23 ... drive layer, 31 ... piezoelectric film layer, 32 ... upper electrode layer, 33 ... lower electrode layer, 41, 42, 43, 44, 51, 52, 53, 54, 61, 62 , 71, 72, 73, 74, 75, 76, 77, 81, 82, 83, 84, 85, 86... Recess, 100, 140.

Claims (8)

A reflecting portion (13, 412) having a reflecting surface for reflecting the light beam;
A first elastic deformation member (16a, 16b, 414a, 414b) serving as a first rotation shaft for torsionally vibrating the reflecting portion;
Driving units (4a, 4b, 4c, 4d, 404a, 404b, 404c, 404d, 404e, 404f, 404g, 404h) for generating a driving force for torsionally vibrating the reflecting portion around the first rotation axis An optical scanning device (1,401) comprising:
The drive unit includes a drive layer (23) formed by sandwiching the piezoelectric film layer (31) between the first electrode layer (32) and the second electrode layer (33), and a support for supporting the drive layer. A layer (21) is laminated along a direction perpendicular to the first rotation axis;
Furthermore, one end of the drive unit is fixed as a fixed end, and the drive unit bends when a voltage is applied between the first electrode layer and the second electrode layer, and the other end is displaced as a free end. Is configured as
The support layer has a recess (41, 42, 43, 44, 51, 52, 53, 54, 61, 62, 71, 72, 73, 74, 75, 76) having the same depth as the support layer. , 77, 81, 82, 83, 84, 85, 86) ,
A direction from the fixed end toward the free end on the surface of the support layer is a first direction, and a direction perpendicular to the first direction on the surface of the support layer is a second direction,
The plurality of recesses (71, 72, 73, 74, 75, 76) are arranged so that the interval between the two recesses adjacent to each other along the first direction becomes longer toward the fixed end. An optical scanning device. A reflecting portion (13, 412) having a reflecting surface for reflecting the light beam;
A first elastic deformation member (16a, 16b, 414a, 414b) serving as a first rotation shaft for torsionally vibrating the reflecting portion;
Driving units (4a, 4b, 4c, 4d, 404a, 404b, 404c, 404d, 404e, 404f, 404g, 404h) for generating a driving force for torsionally vibrating the reflecting portion around the first rotation axis An optical scanning device (1,401) comprising:
The drive unit includes a drive layer (23) formed by sandwiching the piezoelectric film layer (31) between the first electrode layer (32) and the second electrode layer (33), and a support for supporting the drive layer. A layer (21) is laminated along a direction perpendicular to the first rotation axis;
Furthermore, one end of the drive unit is fixed as a fixed end, and the drive unit bends when a voltage is applied between the first electrode layer and the second electrode layer, and the other end is displaced as a free end. Is configured as
The support layer has a recess (41, 42, 43, 44, 51, 52, 53, 54, 61, 62, 71, 72, 73, 74, 75, 76) having the same depth as the support layer. , 77, 81, 82, 83, 84, 85, 86),
A direction from the fixed end toward the free end on the surface of the support layer is a first direction,
It said recess (81,82,83,84,85,86) of the length along the first direction, the optical scanning device you characterized by shorter closer to the fixed end. A reflecting portion (13, 412) having a reflecting surface for reflecting the light beam;
A first elastic deformation member (16a, 16b, 414a, 414b) serving as a first rotation shaft for torsionally vibrating the reflecting portion;
Driving units (4a, 4b, 4c, 4d, 404a, 404b, 404c, 404d, 404e, 404f, 404g, 404h) for generating a driving force for torsionally vibrating the reflecting portion around the first rotation axis An optical scanning device (1,401) comprising:
The drive unit includes a drive layer (23) formed by sandwiching the piezoelectric film layer (31) between the first electrode layer (32) and the second electrode layer (33), and a support for supporting the drive layer. A layer (21) is laminated along a direction perpendicular to the first rotation axis;
Furthermore, one end of the drive unit is fixed as a fixed end, and the drive unit bends when a voltage is applied between the first electrode layer and the second electrode layer, and the other end is displaced as a free end. Is configured as
The support layer has a recess (41, 42, 43, 44, 51, 52, 53, 54, 61, 62, 71, 72, 73, 74, 75, 76) having the same depth as the support layer. , 77, 81, 82, 83, 84, 85, 86),
A direction from the fixed end toward the free end on the surface of the support layer is a first direction,
Of the two recesses adjacent along the first direction, the recess close to the fixed end is defined as a first recess (61), and the remaining recess is defined as a second recess (62).
The length of the first recess along the first direction is defined as a first recess width,
The interval between the first recess and the second recess is a recess interval,
Said first recess width, the optical scanning device you being a 0.8 to 0.9 times the sum of the said recess distance between the first recess width. A direction from the fixed end toward the free end on the surface of the support layer is a first direction, and a direction perpendicular to the first direction on the surface of the support layer is a second direction,
The length along the second direction of the recess (51, 52, 53, 54) is, claims 1 to 3, characterized in that shorter than the length along the second direction of the support layer The optical scanning device according to any one of the above. The optical scanning device according to any one of claims 1 to 4 , wherein the piezoelectric film layer is made of lead zirconate titanate (PZT). A first support part (411) for supporting the first elastic deformation member (414a, 414b);
A second elastically deformable member (413a, 413b) that is elastically deformable connected to the first support part, and the first support part is swingably supported by using the second elastically deformable member as a second rotating shaft. A second support portion (403) that
The second rotation axis is arranged to intersect the first rotation axis,
The first support portion is swung about the second rotation axis, and the reflection portion is swung about the first rotation axis, so that the light beam reflected by the reflection surface is 2 The optical scanning device (401) according to any one of claims 1 to 5 , wherein scanning is performed in a dimension. A first support part (12) for supporting the first elastic deformation member (16a, 16b);
A second elastically deformable member (15a, 15b) that is elastically deformable connected to the first support part, and the first support part is swingably supported using the second elastically deformable member as a second rotating shaft. A second support part (11)
A third elastic deformation member (14a, 14b) that is elastically deformable connected to the second support part, and the second support part is swingably supported by using the third elastic deformation member as a third rotating shaft. And a third support part (3)
The second rotation axis is arranged to intersect the first rotation axis,
The third rotation axis is arranged to intersect the first rotation axis and the second rotation axis,
The reflective portion, the first support portion, the second support portion, the third support portion, the first elastic deformation member, the second elastic deformation member, and the third elastic deformation member have inherent periodic external forces. A three-degree-of-freedom coupled vibration system that twists and vibrates at a large rotation angle when
By causing the inherent periodic external force to act on the three-degree-of-freedom coupled vibration system, the second support portion is swung about the third rotation axis, and the second rotation axis is the center. The light beam reflected by the reflecting surface is scanned two-dimensionally by swinging the first support portion and further swinging the reflection portion about the first rotation axis. The optical scanning device (1) according to any one of claims 1 to 5 . It is a manufacturing method of the optical scanning device according to any one of claims 1 to 7 ,
A first forming step of forming the recess by etching from one side of the first silicon substrate (100);
A bonding step of bonding the first silicon substrate and the second silicon substrate (140) on the one surface side of the first silicon substrate;
A second forming step of forming the drive unit on the other surface side of the first silicon substrate;
A third forming step of forming the reflective portion and the first elastic deformation member by etching from the other surface side of the first silicon substrate;
Etching from the surface side of the second silicon substrate opposite to the bonding surface by twisting the reflecting portion twisted by using the surface where the first silicon substrate and the second silicon substrate are bonded to each other as a bonding surface And a fourth forming step for forming a space that can vibrate.