Optical reflection element

Abstract

An optical reflection element for driving a movable part by a drive part comprises: a metal reflection film (130) disposed in a movable part region on a substrate (101); a piezoelectric body (110) disposed in the region of the drive part (12) on the substrate (101); a first film (121) formed on a lower surface of the metal reflection film (130); a second film (122) formed on an upper surface of the metal reflection film (130) and comprising the same material as the first film (121); and a protection film (140) formed on the upper side of the piezoelectric body (110) in a piezoelectric body region, comprising the same material as the first film (121) in the movable part region, and having substantially the same thickness as the total value of the respective thicknesses of the first film (121) and the second film (122) in the movable part region.

Description

Optical Reflective Elements

[0001] The present invention relates to an optical reflecting element that drives a movable part on which a reflecting surface for reflecting light is formed.

[0002] In recent years, optical reflecting elements that rotate a movable part having a reflective surface using MEMS (Micro Electro Mechanical System) technology have been developed. This type of optical reflecting element is mounted on image display devices such as head-up displays and head-mounted displays. In addition, this type of optical reflecting element can also be used in laser radars that detect objects using laser light.

[0003] Patent Document 1 below describes an optical reflecting element in which a movable part is rotated by a so-called tuning fork vibrator. In this optical reflecting element, a piezoelectric body (piezoelectric actuator) consisting of a first electrode layer, a piezoelectric body layer, and a second electrode layer is formed on an arm. By driving the piezoelectric body, a reflecting part, which is a movable part, is rotated.

[0004] Patent No. 5045470

[0005] In the optical reflecting element having the above-described configuration, a metal reflective film can be formed on the upper surface of the movable part. Furthermore, various films, such as a protective film, a reflective film, and a base film, are individually formed on the upper surface of the piezoelectric element and the upper and lower surfaces of the metal reflective film, with thicknesses and materials suited to the purpose. For this reason, the process of forming these films is quite complicated.

[0006] In view of the above problems, an object of the present invention is to provide an optical reflecting element in which a plurality of films to be laminated on a piezoelectric body and a metal reflecting film can be formed by a simpler process.

[0007] A first aspect of the present invention relates to an optical reflecting element having a movable portion driven by a driving portion, the optical reflecting element according to this aspect comprising: a metal reflective film disposed on a substrate in a region of the movable portion; a piezoelectric body disposed on the substrate in a region of the driving portion; a first film formed on a lower surface of the metal reflective film; a second film formed on an upper surface of the metal reflective film and made of the same material as the first film; and a protective film formed on the piezoelectric body, made of the same material as the first film, and having a thickness substantially equal to the sum of the thicknesses of the first film and the second film.

[0008] The first film is provided to adhere the lower surface of the metal reflective film to the upper surface of the movable part, and the second film is provided to increase the reflectivity beyond that of the metal reflective film itself. Also, a protective film is formed on the upper side of the piezoelectric body to electrically insulate the piezoelectric body from the outside and prevent the intrusion of water vapor, moisture, etc. For these purposes, the protective film on the piezoelectric body side is usually thicker than the first and second films on the metal reflective film side.

[0009] In contrast, in the optical reflecting element according to the present embodiment, by selecting materials for the first and second films that can simultaneously satisfy the above requirements for the metal reflective film and the piezoelectric body, in the process of forming the first and second films above and below the metal reflective film, a protective film can be simultaneously formed on the top side of the piezoelectric body by laminating these films together. Furthermore, since this protective film has a thickness that is the sum of the thicknesses of the first and second films, it meets the thickness requirements for the protective film on the piezoelectric body.

[0010] Therefore, with the optical reflecting element according to this aspect, the multiple films laminated on the piezoelectric body and the metal reflecting film can be formed by a simpler process.

[0011] A second aspect of the present invention relates to an optical reflecting element having a movable part driven by a driving part, the optical reflecting element according to this aspect comprising: a metal reflective film disposed on a substrate in a region of the movable part; a piezoelectric body disposed on the substrate in a region of the driving part; a first dielectric film formed on an upper surface of the metal reflective film; a second dielectric film formed on the upper surface of the first dielectric film and having a refractive index higher than that of the first dielectric film; and at least one of a first protective film formed on the piezoelectric body, the first protective film being made of the same material as the first dielectric film and having a thickness substantially the same as that of the first dielectric film, and a second protective film being made of the same material as the second dielectric film and having a thickness substantially the same as that of the second dielectric film.

[0012] The first and second dielectric films are provided to increase the reflectance higher than that of the metal reflective film itself. Also, a protective film is formed on the upper side of the piezoelectric body to electrically shield the piezoelectric body from the outside and prevent the intrusion of water vapor, moisture, etc.

[0013] In contrast, with the optical reflecting element of this embodiment, by selecting materials for the first and second dielectric films that can simultaneously meet the above requirements on the metal reflecting film side and the above requirements on the piezoelectric body side, in the process of forming the first and second dielectric films on the upper surface of the metal reflecting film, at least one of these films can also be simultaneously formed on the upper side of the piezoelectric body as a protective film.

[0014] Therefore, with the optical reflecting element according to this aspect, the multiple films laminated on the piezoelectric body and the metal reflecting film can be formed by a simpler process.

[0015] A third aspect of the present invention relates to an optical reflecting element having a movable part driven by a driving part, the optical reflecting element according to this aspect comprising: a metal reflective film disposed on a substrate in the region of the movable part; a piezoelectric element disposed on the substrate in the region of the driving part; a first film formed on a lower surface of the metal reflective film; and a protective film formed on an upper side of the piezoelectric element, the protective film being made of the same material as the first film and having a thickness substantially the same as that of the first film.

[0016] The first film is provided to adhere the lower surface of the metal reflective film to the upper surface of the movable part, and a protective film is formed on the upper side of the piezoelectric body to electrically shield the piezoelectric body from the outside and prevent the intrusion of water vapor, moisture, etc.

[0017] In contrast, with the optical reflecting element of this embodiment, by selecting materials for the first film and the protective film that can simultaneously meet the above requirements on the metal reflecting film side and the above requirements on the piezoelectric body side, in the process of forming the first film on the underside of the metal reflecting film, a protective film can also be formed on the upper side of the piezoelectric body at the same time.

[0018] Therefore, with the optical reflecting element according to this aspect, the multiple films laminated on the piezoelectric body and the metal reflecting film can be formed by a simpler process.

[0019] As described above, according to the present invention, an optical reflecting element can be provided in which a plurality of films to be laminated on the piezoelectric body and the metal reflecting film can be formed by a simpler process.

[0020] The effects and significance of the present invention will become more apparent from the following description of the embodiments, however, the embodiments shown below are merely examples of how the present invention can be implemented, and the present invention is not limited to the embodiments described below.

[0021] FIG. 1 is a perspective view showing the configuration of an optical reflecting element according to Embodiment 1. FIG. 2 is a perspective view of the optical reflecting element according to Embodiment 1 when viewed from the bottom side. FIGS. 3(a) and 3(b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Embodiment 1. FIGS. 4(a) and 4(b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Embodiment 1. FIGS. 5(a) and 5(b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Embodiment 1. FIGS. 6(a) and 6(b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Embodiment 2. FIGS. 7(a) and 7(b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Embodiment 2. FIGS. 8(a) and 8(b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Embodiment 2. FIGS. 9(a) and 9(b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Modification Example 1 of Embodiment 2. Figures 10(a) and (b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Modification 1 of Embodiment 2. Figures 11(a) and (b) are cross-sectional views schematically showing a layered structure of an optical reflecting element according to Modification 2 of Embodiment 2. Figures 12(a) and (b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Embodiment 3. Figures 13(a) and (b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Embodiment 3. Figures 14(a) and (b) are cross-sectional views schematically showing a procedure for forming a layered structure of an optical reflecting element according to Embodiment 3.

[0022] However, the drawings are for illustrative purposes only and do not limit the scope of the present invention.

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, each drawing is labeled with X, Y, and Z axes that are orthogonal to each other. The Y axis direction is parallel to the rotation axis of the optical reflecting element, and the Z axis direction is the thickness direction of the optical reflecting element.

[0024] First Embodiment FIG. 1 is a perspective view showing the configuration of an optical reflecting element 1, and FIG. 2 is a perspective view of the optical reflecting element 1 as viewed from the bottom side (Z-axis negative side).

[0025] The optical reflecting element 1 includes a movable portion 11, two drive portions 12, two torsion portions 13, two connecting portions 14, and a fixed portion 15. The optical reflecting element 1 has a rectangular outline in a plan view. The optical reflecting element 1 has a shape that is symmetrical in the Y-axis direction and in the X-axis direction about the center of the movable portion 11.

[0026] Movable portion 11 is supported by fixed portion 15 via two torsion portions 13 and two connecting portions 14 so as to be rotatable about rotation axis R0. Rotation axis R0 extends parallel to the length direction (Y axis direction) of optical reflecting element 1 at the midpoint in the width direction (X axis direction) of optical reflecting element 1. A reflective surface 11a is formed on the upper surface (surface on the positive side of the Z axis) of movable portion 11. The configuration of reflective surface 11a will be described later with reference to FIGS. 3(a) to 5(b).

[0027] The two torsion sections 13 have a beam-like shape extending along the rotation axis R0 and are arranged to sandwich the movable section 11 in the Y-axis direction. One end of the torsion section 13 on the Y-axis positive side is connected to the side surface of the movable section 11 on the Y-axis positive side, and the other end is connected to the connecting section 14 on the Y-axis positive side. One end of the torsion section 13 on the Y-axis negative side is connected to the side surface of the movable section 11 on the Y-axis negative side, and the other end is connected to the connecting section 14 on the Y-axis negative side.

[0028] The two connecting portions 14 have a plate-like shape extending along the rotation axis R0. The connecting portions 14 connect the drive portion 12 and the torsion portion 13 to the fixed portion 15.

[0029] The two driving units 12 each include a piezoelectric actuator 12b as a driving source and rotate the movable unit 11 about a rotation axis R0. Each of the two driving units 12 is formed by a tuning fork vibrator. That is, the two driving units 12 are formed by arranging the two tuning fork vibrators in opposite directions along the rotation axis R0.

[0030] Each drive unit 12 includes a pair of arm units 12a extending in an L-shape from the connecting unit 14. A piezoelectric actuator 12b for driving the movable unit 11 is disposed on the upper surface of the portion of each arm unit 12a extending in the Y-axis direction. In addition, a piezoelectric actuator 12c for detecting the vibration state of the arm unit 12a is disposed near the base of each arm unit 12a.

[0031] The piezoelectric actuators 12b and 12c have a laminated structure in which an upper electrode layer and a lower electrode layer are respectively disposed above and below a piezoelectric layer. The laminated structure of the piezoelectric actuators 12b and 12c will be described later with reference to FIG.

[0032] Fixed portion 15 has a frame shape with a rectangular outline in a plan view. The outer contour of fixed portion 15 forms the outer contour of optical reflecting element 1. Fixed portion 15 supports movable portion 11, drive portion 12, and torsion portion 13 via two connecting portions 14.

[0033] Two terminals 16 are arranged on the upper surface of fixed portion 15. Terminal 16 on the Y-axis positive side is connected to two piezoelectric actuators 12b and two piezoelectric actuators 12c on the Y-axis positive side via wiring 17. Terminal 16 on the Y-axis negative side is connected to two piezoelectric actuators 12b and two piezoelectric actuators 12c on the Y-axis negative side via wiring 17. Similar to piezoelectric actuators 12b and 12c, wiring 17 has a layered structure in which an upper electrode layer and a lower electrode layer are arranged above and below a piezoelectric layer.

[0034] On the upper surface of the terminal portion 16, there are arranged four first electrode pads 16a connected to the upper electrode layers of the corresponding piezoelectric actuators 12b, 12c, and two second electrode pads 16b connected to the lower electrode layers of the corresponding piezoelectric actuators 12b, 12c for connecting these lower electrode layers to ground. The first electrode pads 16a and the second electrode pads 16b are exposed upward. The layered structure of the first electrode pads 16a and the second electrode pads 16b will be described later with reference to Figures 3(a) to 5(b).

[0035] The base portion of optical reflecting element 1 is formed by processing an SOI wafer consisting of substrate 101 and material layer 102. Substrate 101 and material layer 102 each have a certain thickness. Substrate 101 and material layer 102 are made of, for example, silicon (Si). Note that substrate 101 and material layer 102 may be made of different materials, or may be made of a material other than silicon (Si).

[0036] When the optical reflecting element 1 is produced, the reflecting surface 11a, the piezoelectric actuators 12b and 12c, the terminal portion 16, the first electrode pad 16a, the second electrode pad 16b, and the wiring 17 are formed in corresponding regions on the substrate 101 of the SOI wafer. Next, the substrate 101 and the material layer 102 are removed by etching or the like so as to leave the movable portion 11, the drive portion 12, the torsion portion 13, the connecting portion 14, and the fixed portion 15. As a result, the substrate 101 becomes a common substrate for the entire optical reflecting element 1, and an opening 15a penetrating vertically is formed around the movable portion 11. Furthermore, as shown in FIG. 2 , the material layer 102 is removed from the SOI wafer by etching or the like so as to leave a region corresponding to the fixed portion 15. As a result, the mechanical strength of the fixed portion 15 is increased compared to the portions other than the fixed portion 15.

[0037] The optical reflecting element 1 is used by being electrically connected to an external circuit board or the like via the first electrode pads 16 a and the second electrode pads 16 b. The first electrode pads 16 a and the second electrode pads 16 b are connected to the external circuit board or the like by wiring means such as wire bonding. The first electrode pads 16 a and the second electrode pads 16 b may also be connected to the external circuit board or the like via a support substrate. In this case, the support substrate has a plurality of electrode pads arranged in positions facing the plurality of electrode pads on the optical reflecting element 1 side, and the first electrode pads 16 a and the second electrode pads 16 b are connected to the external circuit board or the like by adhering the optical reflecting element 1 to the support substrate.

[0038] When the optical reflecting element 1 is driven, an AC voltage is applied to the four piezoelectric actuators 12b to resonantly drive the movable portion 11 at the natural frequency (resonance frequency) of the optical reflecting element 1. As a result, each of the four piezoelectric actuators 12b deforms due to the inverse piezoelectric effect. At this time, the AC voltages applied to two piezoelectric actuators 12b aligned in the Y-axis direction are set to the same phase, and the AC voltages applied to two piezoelectric actuators 12b aligned in the X-axis direction are set to opposite phases. As a result, the deformation direction (amplitude direction) of the two piezoelectric actuators 12b on the positive side of the X-axis is opposite to the deformation direction (amplitude direction) of the piezoelectric actuator 12b on the negative side of the X-axis. In this way, the deformation of the four piezoelectric actuators 12b deforms the arm portion 12a, and the movable portion 11 is resonantly driven around the rotation axis R0 at a predetermined resonant frequency via the two torsion portions 13.

[0039] The four piezoelectric actuators 12c for vibration detection generate currents due to the piezoelectric effect in response to the deformation of the corresponding arms 12a. Therefore, the vibration state of the arms 12a can be monitored from these currents. An external drive circuit uses these currents to control the AC voltages applied to the piezoelectric actuators 12b so that the amplitude, frequency, and phase of each arm 12a converge to their respective target values. This causes the movable part 11 and the reflecting surface 11a to rotate at the target resonant frequency and deflection angle. Light of a predetermined wavelength band incident on the movable part 11 from above is reflected by the reflecting surface 11a of the movable part 11 and irradiated onto the target area.

[0040] Next, the procedure for forming the layered structure of optical reflecting element 1 will be described with reference to the cross-sectional views of FIGS. 3(a) to 5(b).

[0041] 3(a) to 5(b) show schematic cross sections of the laminated structure in the "piezoelectric body region," "first electrode pad region," "second electrode pad region," and "movable portion region." The piezoelectric body region is the region where the piezoelectric actuators 12b, 12c, the portion of the terminal portion 16 excluding the first electrode pad 16a and the second electrode pad 16b, and the wiring 17 are arranged. The first electrode pad region is the region where the first electrode pad 16a is arranged. The second electrode pad region is the region where the second electrode pad 16b is arranged. The movable portion region is the region where the movable portion 11 is located.

[0042] 3(a) to 5(b) show only the upper end of the substrate 101 of the SOI wafer made up of the substrate 101 and the material layer 102 for convenience. Each layer of the laminated structure is formed by a PVD (physical vapor deposition) method typified by sputtering or evaporation, a CVD (chemical vapor deposition) method, a liquid phase deposition method typified by a sol-gel method, or the like. Each layer of the laminated structure is removed by applying a resist, dry etching, wet etching, or the like.

[0043] The procedure for forming the laminated structure in these regions will be described below.

[0044] 3(a) to 5(b), a piezoelectric body 110 is formed on the upper surface of the SOI wafer substrate 101 in the piezoelectric body region, first electrode pad region, and second electrode pad region, with a lower electrode layer 111, a piezoelectric body layer 112, and an upper electrode layer 113 stacked in this order from top to bottom. The lower electrode layer 111 is made of a material with low electrical resistance and high heat resistance, such as platinum (Pt). The piezoelectric body layer 112 is made of, for example, PZT (lead zirconate titanate: Pb(Zr,Ti)O ３ The upper electrode layer 113 is made of a material having low electrical resistance and high heat resistance, such as gold (Au).

[0045] In order to improve the adhesion between the substrate 101 and the lower electrode layer 111, an adhesion layer may be disposed between the substrate 101 and the lower electrode layer 111, and in order to improve the adhesion between the piezoelectric layer 112 and the upper electrode layer 113, an adhesion layer may be disposed between the piezoelectric layer 112 and the upper electrode layer 113. In this case, the adhesion layer is made of, for example, titanium (Ti).

[0046] 3A, the piezoelectric layer 112 and the upper electrode layer 113 are removed from the second electrode pad region. In this way, the piezoelectric actuators 12b and 12c made of the piezoelectric body 110, the portion of the terminal portion 16 excluding the first electrode pad 16a and the second electrode pad 16b, and the wiring 17 are formed in the piezoelectric region, the first electrode pad 16a made of the piezoelectric body 110 is formed in the first electrode pad region, and the second electrode pad 16b made of the lower electrode layer 111 is formed in the second electrode pad region.

[0047] Next, a first film 121 is formed on the upper surface of the structure shown in FIG. 3( a). The first film 121 is formed over the entire range of the substrate 101 in a plan view. As a result, as shown in FIG. 3( b), the first film 121 of a predetermined thickness is laminated in the piezoelectric body region, the first electrode pad region, the second electrode pad region, and the movable portion region. The first film 121 in the movable portion region is provided to tightly attach the lower surface of a metal reflective film 130 (described later) to the upper surface of the substrate 101, and the first film 121 in the piezoelectric body region is provided to electrically shield the piezoelectric body 110 from the outside and prevent the intrusion of water vapor, moisture, etc. For this reason, the first film 121 is made of, for example, alumina (Al ２ O ３ ) or alumina (Al ２ O ３ The first film 121 is configured to have a thickness of, for example, about 20 nm or more so as to ensure adhesion between the metal reflective film 130 and the substrate 101.

[0048] Next, a metal reflective film 130 is formed on the upper surface of the structure shown in FIG. 3( b). The metal reflective film 130 is formed over the entire area of ​​the substrate 101 in a plan view. As a result, as shown in FIG. 4( a), the metal reflective film 130 is laminated to a predetermined thickness in the piezoelectric region, the first electrode pad region, the second electrode pad region, and the movable portion region. The metal reflective film 130 is made of, for example, silver (Ag) or a silver (Ag) alloy to increase the reflectivity of light incident on the movable portion 11. The silver alloy is, for example, an alloy made of silver (Ag), Pd (palladium), and copper (Cu), and an APC (registered trademark) alloy can be used. The metal reflective film 130 can also be made of two layers using a metal film such as titanium (Ti) as an underlayer.

[0049] Next, in the structure shown in Fig. 4(a), the metal reflective film 130 is removed from all areas except the movable portion area, leaving the metal reflective film 130 only in the movable portion area, as shown in Fig. 4(b).

[0050] Next, a second film 122 and a third film 123 are formed in this order on the upper surface of the structure shown in Fig. 4(b) . The second film 122 and the third film 123 are formed over the entire area of ​​the substrate 101 in a plan view. As a result, the second film 122 of a predetermined thickness and the third film 123 of a predetermined thickness are laminated in the piezoelectric body region, the first electrode pad region, the second electrode pad region, and the movable portion region, as shown in Fig. 5(a) .

[0051] The second film 122 and the third film 123 in the movable portion area are provided to increase the reflectance higher than that of the metal reflective film 130 itself, and the second film 122 and the third film 123 in the piezoelectric body area are provided to electrically shield the piezoelectric body 110 from the outside and to prevent the intrusion of water vapor, moisture, etc. For this reason, the second film 122 is made of, for example, alumina (Al ２ O ３ ) or alumina (Al ２ O ３ The third film 123 is made of a material having a higher refractive index than the second film 122, for example, zirconia (ZrO ２ ) or the main component is zirconia (ZrO ２By forming the third film 123 from a material having a higher refractive index than the second film 122, a dielectric multilayer film can be formed based on the second film 122 and the third film 123, and the reflectance of light incident on the movable part 11 can be further increased.

[0052] When the first film 121 and the second film 122 are made of the same material as in this embodiment, the first film 121 and the second film 122 are integrally formed in the piezoelectric region, the first electrode pad region, and the second electrode pad region to form the protective film 140. The protective film 140 has a thickness substantially equal to the sum of the thicknesses of the first film 121 and the second film 122 in the movable portion region. In Figure 5(a) , for convenience, the boundary between the first film 121 and the second film 122 is indicated by a dashed line.

[0053] Here, when light of wavelength λ is to be reflected by movable portion 11, the thicknesses of second film 122 and third film 123 in the movable portion region are each set to approximately λ / 4. Therefore, when the wavelength λ of light to be reflected is set to approximately 350 nm or more and 800 nm or less, and second film 122 is made of alumina and third film 123 is made of zirconia, the refractive index of alumina is approximately 1.6, so the thickness of second film 122 is set to approximately 55 nm or more and 125 nm or less, and the refractive index of zirconia is approximately 2.1, so the thickness of third film 123 is set to approximately 40 nm or more and 95 nm or less.

[0054] Furthermore, by setting the thickness of the alumina on the upper side of the piezoelectric body 110 in the piezoelectric body region to about 80 nm or more, it is possible to realize moisture resistance on the upper surface of the piezoelectric body 110 in the piezoelectric body region. Furthermore, by setting the thickness of the zirconia on the upper side of the piezoelectric body 110 in the piezoelectric body region to about 20 nm or more, it is possible to realize warm water resistance on the upper surface of the piezoelectric body 110 in the piezoelectric body region.

[0055] From the above, when the first film 121 and the second film 122 are made of alumina and the third film 123 is made of zirconia, the thickness of the first film 121 is set to approximately 25 nm to 175 nm and the thickness of the second film 122 is set to approximately 55 nm to 125 nm, thereby setting the thickness of the protective film 140 (the first film 121 and the second film 122) to approximately 80 nm to 300 nm. Furthermore, the thickness of the third film 123 is set to approximately 40 nm to 95 nm. Setting the film thicknesses of the first film 121, the second film 122, and the third film 123 in this manner achieves adhesion between the metal reflective film 130 and the substrate 101, improved reflectivity due to the movable portion 11, and moisture resistance and warm water resistance of the piezoelectric body 110 in the piezoelectric body region.

[0056] In addition, if the thickness of the protective film 140 is not sufficient to protect the piezoelectric body 110 from the outside, the thickness of the first film 121 may be set to be greater than the above range, and other films may be formed on the upper and lower surfaces of the protective film 140.

[0057] The second film 122 and the third film 123 are not limited to being made of the above materials. The second film 122 and the third film 123 may be made of any material as long as they can transmit light that is to be reflected by the movable part 11 and are resistant to moisture and warm water. The second film 122 and the third film 123 may be made of a dielectric material such as an oxide or a fluoride, for example, ZrO ２ , Al ２ O ３ , Ta ２ O ５ , TiO ２ , and SiO ２ , and the main component is ZrO ２ , Al ２ O ３ , Ta ２ O ５ , TiO ２ , and SiO ２ The material is composed of a material selected from the group consisting of a mixture of materials in which

[0058] Next, in the structure shown in Fig. 5(a), the second film 122 and the third film 123 are removed from all regions except the piezoelectric region and the movable portion region. As a result, the second film 122 and the third film 123 remain in the piezoelectric region and the movable portion region, as shown in Fig. 5(b). In the first embodiment, the upper surface of the metal reflective film 130, the second film 122, and the third film 123 form a reflective surface 11a on the movable portion 11.

[0059] It should be noted that no laminated structure is formed on the upper surface of the substrate 101 in areas other than the piezoelectric body area, the first electrode pad area, the second electrode pad area, and the movable portion area.

[0060] 5(b), after the laminated structure is formed on substrate 101, as described above, substrate 101 and material layer 102 are removed by etching or the like so as to leave movable portion 11, drive portion 12, torsion portion 13, connecting portion 14, and fixed portion 15. Furthermore, material layer 102 is removed by etching or the like from the SOI wafer so as to leave a region corresponding to fixed portion 15. In this way, optical reflecting element 1 is completed.

[0061] <Effects of First Embodiment> According to the first embodiment, the following effects are achieved.

[0062] As shown in Figures 1 and 5(b), the optical reflecting element 1, which drives the movable part 11 by the driving part 12, comprises a metal reflective film 130 arranged in the region of the movable part 11 on the substrate 101, a piezoelectric body 110 arranged in the region of the driving part 12 on the substrate 101, a first film 121 formed on the underside of the metal reflective film 130, a second film 122 formed on the upper surface of the metal reflective film 130 and made of the same material as the first film 121, and a protective film 140 formed on the upper side of the piezoelectric body 110 in the region of the driving part 12, made of the same material as the first film 121 in the region of the movable part 11, and having a thickness substantially the same as the sum of the thicknesses of the first film 121 and the second film 122 in the region of the movable part 11.

[0063] The first film 121 is provided to bring the lower surface of the metal reflective film 130 into close contact with the upper surface of the movable section 11, and the second film 122, together with the third film 123, is provided to increase the reflectance beyond that of the metal reflective film 130 itself. In addition, a protective film 140 is formed on the upper side of the piezoelectric body 110 in the region of the drive section 12 to electrically shield the piezoelectric body 110 from the outside and prevent the intrusion of water vapor, moisture, and the like. For these purposes, the protective film 140 on the piezoelectric body 110 side is usually thicker than the first film 121 and second film 122 on the metal reflective film 130 side.

[0064] In contrast, with the above configuration, by selecting materials for the first film 121 and the second film 122 that can simultaneously meet the above requirements for the metal reflective film 130 and the piezoelectric body 110, it is possible to simultaneously form the protective film 140 by laminating these films on the upper side of the piezoelectric body 110 in the process of forming the first film 121 and the second film 122 above and below the metal reflective film 130. Furthermore, since this protective film 140 has a thickness that is the sum of the thicknesses of the first film 121 and the second film 122, it meets the thickness requirement for the protective film 140 of the piezoelectric body 110.

[0065] Therefore, with the above configuration, the multiple films laminated on the piezoelectric body 110 and the metal reflective film 130 can be formed by a simpler process.

[0066] The metal reflective film 130 is made of silver (Ag) or a silver (Ag) alloy, and the first film 121 and the second film 122 are made of alumina (Al ２ O ３ ) or alumina (Al ２ O ３ ) is composed of a mixture of materials.

[0067] According to this configuration, the metal reflective film 130 is made of silver or a silver alloy, and the second film 122 contains alumina, thereby improving the adhesion between the metal reflective film 130 and the second film 122. Furthermore, the first film 121 contains alumina, thereby improving the adhesion between the metal reflective film 130 and the substrate 101. Furthermore, the protective film 140 (first film 121 and second film 122) contains alumina, thereby making the upper surface of the piezoelectric body 110 moisture-resistant.

[0068] As shown in FIG. 5( b ), optical reflecting element 1 further includes third film 123 formed on the upper surface of second film 122 in the region of movable section 11 and having a refractive index higher than that of second film 122 .

[0069] This configuration can further increase the reflectance of light incident on the upper surface side of the movable portion 11.

[0070] As shown in FIG. 5B, a third film 123 (another protective film) is provided, which is formed on the upper side of the protective film 140, is made of the same material as the third film 123, and has substantially the same thickness as the third film 123.

[0071] This configuration can improve electrical shielding of the piezoelectric body 110 in the region of the driving section 12 .

[0072] The third film 123 is made of zirconia (ZrO ２ ) or the main component is zirconia (ZrO ２ ) is composed of a mixture of materials.

[0073] According to this configuration, when the second film 122 contains alumina, the refractive index of the third film 123 can be set higher than the refractive index of the second film 122, thereby increasing the light reflectance. In addition, the third film 123 can make the piezoelectric body 110 in the region of the drive unit 12 resistant to warm water.

[0074] <Embodiment 2> In embodiment 1, first film 121 and second film 122 are respectively disposed on the lower surface and upper surface of metal reflective film 130. In contrast, in embodiment 2, first film 121 is not disposed on the lower surface of metal reflective film 130. Hereinafter, the procedure for forming optical reflecting element 1 in embodiment 2 will be described with reference to Figures 6(a) to 8(b).

[0075] Fig. 6(a) shows a state similar to Fig. 3(b) in embodiment 1. In the structure shown in Fig. 6(a), the first film 121 is removed from all regions except the piezoelectric region. As a result, the first film 121 remains only in the piezoelectric region, as shown in Fig. 6(b).

[0076] Next, a metal reflective film 130 is formed on the upper surface of the structure shown in Fig. 6(b). The metal reflective film 130 is formed over the entire area of ​​the substrate 101 in plan view. As a result, as shown in Fig. 7(a), the metal reflective film 130 having a predetermined thickness is laminated over the piezoelectric body region, the first electrode pad region, the second electrode pad region, and the movable portion region.

[0077] Next, in the structure shown in Fig. 7A, the metal reflective film 130 is removed from all areas except the movable portion area, leaving the metal reflective film 130 only in the movable portion area, as shown in Fig. 7B.

[0078] Next, a second film 122 and a third film 123 are formed in this order upward on the upper surface of the structure shown in Fig. 7(b). The second film 122 and the third film 123 are formed over the entire area of ​​the substrate 101 in a plan view. As a result, as shown in Fig. 8(a), the second film 122 of a predetermined thickness and the third film 123 of a predetermined thickness are laminated in the piezoelectric body region, the first electrode pad region, the second electrode pad region, and the movable portion region. Furthermore, a protective film 140 made of the first film 121 and the second film 122 is formed in the piezoelectric body region.

[0079] The second film 122 and the third film 123 in the movable portion region are provided to increase the reflectance higher than that of the metal reflective film 130 itself, and the second film 122 and the third film 123 in the piezoelectric region are provided to electrically shield the piezoelectric body 110 from the outside and prevent the intrusion of water vapor, moisture, etc. For this reason, the second film 122 and the third film 123 are made of, for example, the same material as in the first embodiment.

[0080] Next, in the structure shown in Fig. 8(a), second film 122 and third film 123 are removed from all regions except the piezoelectric region and the movable portion region. As a result, second film 122 and third film 123 remain in the piezoelectric region and the movable portion region, as shown in Fig. 8(b). Thereafter, as in the first embodiment, etching or the like is performed on substrate 101 and material layer 102, and optical reflecting element 1 is completed.

[0081] In this embodiment, when the wavelength λ of light to be reflected is set to approximately 350 nm or more and 800 nm or less, the second film 122 is made of alumina, and the third film 123 is made of zirconia, the thickness of the first film 121 is set to approximately 25 nm or more and 175 nm or less, and the thickness of the second film 122 is set to approximately 55 nm or more and 125 nm or less, thereby setting the thickness of the protective film 140 (first film 121 and second film 122) to approximately 80 nm or more and 300 nm or less. The thickness of the third film 123 is set to approximately 40 nm or more and 95 nm or less. Setting the film thicknesses of the second film 122 and the third film 123 in this manner improves the reflectivity of the movable portion 11 and provides moisture resistance and warm water resistance to the piezoelectric body 110 in the piezoelectric body region.

[0082] <Effects of Second Embodiment> According to the second embodiment, the following effects are achieved.

[0083] As shown in FIGS. 1 and 8B, optical reflecting element 1, which drives movable portion 11 by drive portion 12, includes metal reflective film 130 arranged in the region of movable portion 11 on substrate 101, piezoelectric body 110 arranged in the region of drive portion 12 on substrate 101, second film 122 (first dielectric film) formed on the upper surface of metal reflective film 130, third film 123 (second dielectric film) formed on the upper surface of second film 122 (first dielectric film) and having a refractive index higher than that of second film 122 (first dielectric film), and drive portion 12. and at least one of a second film 122 (first protective film) made of the same material as the second film 122 (first dielectric film) in the movable portion 11 region and having substantially the same thickness as the second film 122 (first dielectric film) in the movable portion 11 region, and a third film 123 (second protective film) made of the same material as the third film 123 (second dielectric film) in the movable portion 11 region and having substantially the same thickness as the third film 123 (second dielectric film) in the movable portion 11 region.

[0084] The second film 122 (first dielectric film) and the third film 123 (second dielectric film) are provided to increase the reflectance higher than that of the metal reflective film 130 itself. In addition, a protective film is formed on the upper side of the piezoelectric body 110 in the region of the driving section 12 to electrically shield the piezoelectric body 110 from the outside and prevent the intrusion of water vapor, moisture, and the like.

[0085] In contrast, with the above configuration, by selecting materials for the second film 122 (first dielectric film) and the third film 123 (second dielectric film) that can simultaneously meet the above requirements on the metal reflective film 130 side and the above requirements on the piezoelectric body 110 side, in the process of forming the second film 122 (first dielectric film) and the third film 123 (second dielectric film) on the upper surface of the metal reflective film 130, at least one of these films can also be simultaneously formed on the upper side of the piezoelectric body 110 as a protective film.

[0086] Therefore, with the above configuration, the multiple films laminated on the piezoelectric body 110 and the metal reflective film 130 can be formed by a simpler process.

[0087] The metal reflective film 130 is made of silver (Ag) or a silver (Ag) alloy, and the second film 122 (first dielectric film) is made of alumina (Al ２ O ３ ) or alumina (Al ２ O ３ The metal reflective film 130 may be made of a two-layer structure with a metal film such as titanium (Ti) as an underlayer.

[0088] According to this configuration, the metal reflective film 130 is made of silver or a silver alloy, and the second film 122 (first dielectric film) contains alumina, thereby improving adhesion between the metal reflective film 130 and the second film 122 (first dielectric film). Furthermore, when the second film 122 (first dielectric film) is formed on the upper side of the piezoelectric body 110, the moisture resistance of the upper surface of the piezoelectric body 110 can be achieved by having the second film 122 (first dielectric film) contain alumina.

[0089] The third film 123 (second dielectric film) is made of zirconia (ZrO ２ ) or the main component is zirconia (ZrO ２ ) is composed of a mixture of materials.

[0090] According to this configuration, when the second film 122 (first dielectric film) contains alumina, the refractive index of the third film 123 (second dielectric film) can be set higher than the refractive index of the second film 122 (first dielectric film), thereby increasing the light reflectance. Furthermore, when the third film 123 (second dielectric film) is formed on the upper side of the piezoelectric body 110, the third film 123 (second dielectric film) contains zirconia, thereby making the upper surface of the piezoelectric body 110 resistant to warm water.

[0091] Furthermore, in accordance with the second embodiment, the first film 121 in the area of ​​the movable portion 11 is omitted compared to the first embodiment, which reduces the weight of the movable portion 11 and allows the movable portion 11 to rotate efficiently. However, in order to improve the adhesion between the substrate 101 and the metal reflective film 130, it is preferable to dispose the first film 121 as in the first embodiment.

[0092] <Modification 1 of Embodiment 2> In Embodiment 2, protective film 140 made of first film 121 and second film 122 is formed in the piezoelectric region, but first film 121 may be omitted. The procedure for forming optical reflecting element 1 in this modification will be described below with reference to Figures 9(a) to 10(b).

[0093] In this modified example, a metal reflective film 130 is formed on the upper surface of the structure shown in Fig. 3(a). The metal reflective film 130 is formed over the entire area of ​​the substrate 101 in a plan view. As a result, as shown in Fig. 9(a), the metal reflective film 130 of a predetermined thickness is laminated over the piezoelectric body region, the first electrode pad region, the second electrode pad region, and the movable portion region.

[0094] Next, in the structure shown in Fig. 9A, the metal reflective film 130 is removed from all areas except the movable portion area, leaving the metal reflective film 130 only in the movable portion area, as shown in Fig. 9B.

[0095] Next, a second film 122 and a third film 123 are formed in this order on the upper surface of the structure shown in Fig. 9(b) . The second film 122 and the third film 123 are formed over the entire area of ​​the substrate 101 in a plan view. As a result, the second film 122 of a predetermined thickness and the third film 123 of a predetermined thickness are laminated in the piezoelectric body region, the first electrode pad region, the second electrode pad region, and the movable portion region, as shown in Fig. 10(a) .

[0096] Next, in the structure shown in Fig. 10(a), second film 122 and third film 123 are removed from all regions except the piezoelectric region and the movable portion region. As a result, second film 122 and third film 123 are left in the piezoelectric region and the movable portion region, as shown in Fig. 10(b). Thereafter, as in the first embodiment, etching or the like is performed on substrate 101 and material layer 102, and optical reflecting element 1 is completed.

[0097] This modified example also achieves the same effects as in embodiment 2. Furthermore, in this modified example, the first film 121 in the piezoelectric body region is omitted compared to embodiment 2, which reduces the weight of the drive unit 12 and allows the drive unit 12 to be driven efficiently. However, in order to reliably protect the top surface of the piezoelectric body 110 of the drive unit 12, it is preferable to place the first film 121 in the piezoelectric body region as in embodiment 2.

[0098] <Modification 2 of Embodiment 2> In Embodiment 2, both the second film 122 and the third film 123 are formed in the piezoelectric region, but either the second film 122 or the third film 123 may be omitted.

[0099] 11(a), the third film 123 in the piezoelectric region may be omitted compared to Modification 1 of Embodiment 2 shown in FIG. 10(b). In this case, the second film 122 can be formed in the movable portion region and the piezoelectric region by a single process, and the upper surface of the piezoelectric body 110 is protected by the second film 122. Note that another film (for example, the first film 121) may be formed between the second film 122 and the piezoelectric body 110.

[0100] 11(b), the second film 122 in the piezoelectric region may be omitted compared to Modification 1 of Embodiment 2 shown in FIG. 10(b). In this case, the third film 123 can be formed in the movable portion region and the piezoelectric region by a single process, and the top surface of the piezoelectric body 110 is protected by the third film 123. Note that another film (for example, the first film 121) may be formed between the third film 123 and the piezoelectric body 110.

[0101] <Embodiment 3> In embodiment 1, second film 122 and third film 123 are disposed on the upper surface of first film 121 in the piezoelectric region. In contrast, in embodiment 3, second film 122 and third film 123 are not disposed in the piezoelectric region. The procedure for forming optical reflecting element 1 in embodiment 3 will be described below with reference to Figures 12(a) to 14(b).

[0102] 12(a) shows a state similar to that shown in FIG. 3(b) of the first embodiment. The first film 121 in the movable portion region is provided to adhere the lower surface of the metal reflective film 130 to the upper surface of the substrate 101, and the first film 121 in the piezoelectric region is provided to electrically shield the piezoelectric body 110 from the outside and prevent the intrusion of water vapor, moisture, and the like. The first film 121 is made of, for example, the same material as in the first embodiment. In the structure shown in FIG. 12(a), the first film 121 is removed from all regions except the piezoelectric region and the movable portion region. As a result, the first film 121 remains only in the piezoelectric region and the movable portion region, as shown in FIG. 12(b).

[0103] Next, a metal reflective film 130 is formed on the upper surface of the structure shown in Fig. 12(b). The metal reflective film 130 is formed over the entire area of ​​the substrate 101 in plan view. As a result, as shown in Fig. 13(a), the metal reflective film 130 having a predetermined thickness is laminated over the piezoelectric body region, the first electrode pad region, the second electrode pad region, and the movable portion region.

[0104] Next, in the structure shown in Fig. 13(a), the metal reflective film 130 is removed from all areas except the movable portion area, leaving the metal reflective film 130 only in the movable portion area, as shown in Fig. 13(b).

[0105] Next, a second film 122 and a third film 123 are formed in this order upward on the upper surface of the structure shown in Fig. 13(b). The second film 122 and the third film 123 are formed over the entire area of ​​the substrate 101 in a plan view. As a result, as shown in Fig. 14(a), the second film 122 of a predetermined thickness and the third film 123 of a predetermined thickness are laminated in the piezoelectric body region, the first electrode pad region, the second electrode pad region, and the movable portion region. Furthermore, a protective film 140 made of the second film 122 and the third film 123 is formed in the piezoelectric body region.

[0106] Next, in the structure shown in Fig. 14(a), second film 122 and third film 123 are removed from all regions except the movable portion region. As a result, second film 122 and third film 123 remain only in the movable portion region, as shown in Fig. 14(b). Thereafter, as in the first embodiment, etching or the like is performed on substrate 101 and material layer 102, and optical reflecting element 1 is completed.

[0107] In this embodiment, when the wavelength λ of light to be reflected is set to approximately 350 nm or more and 800 nm or less, the first film 121 and the second film 122 are made of alumina, and the third film 123 is made of zirconia, the thickness of the first film 121 is set to approximately 80 nm or more and 300 nm or less, the thickness of the second film 122 is set to approximately 55 nm or more and 125 nm or less, and the thickness of the third film 123 is set to approximately 40 nm or more and 95 nm or less. Setting the film thicknesses of the first film 121, the second film 122, and the third film 123 in this manner makes it possible to achieve adhesion between the metal reflective film 130 and the substrate 101, improvement in reflectivity by the movable portion 11, and moisture resistance of the piezoelectric body 110 in the piezoelectric body region.

[0108] <Effects of Third Embodiment> According to the third embodiment, the following effects are achieved.

[0109] As shown in Figures 1 and 14(b), the optical reflecting element 1, which drives the movable part 11 by the driving part 12, comprises a metal reflecting film 130 arranged in the region of the movable part 11 on the substrate 101, a piezoelectric body 110 arranged in the region of the driving part 12 on the substrate 101, a first film 121 formed on the underside of the metal reflecting film 130, and a first film 121 (protective film) formed on the upper side of the piezoelectric body 110 in the region of the driving part 12, made of the same material as the first film 121 in the region of the movable part 11, and having substantially the same thickness as the first film 121 in the region of the movable part 11.

[0110] The first film 121 is provided to bring the lower surface of the metal reflective film 130 into close contact with the upper surface of the movable section 11. In addition, the first film 121 (protective film) is formed on the upper side of the piezoelectric body 110 in the region of the driving section 12 to electrically shield the piezoelectric body 110 from the outside and prevent the intrusion of water vapor, moisture, and the like.

[0111] In contrast, with the above configuration, by selecting a material for the first film 121 (protective film) that can simultaneously meet the above requirements on the metal reflective film 130 side and the above requirements on the piezoelectric body 110 side, in the process of forming the first film 121 on the underside of the metal reflective film 130, the first film 121 (protective film) can also be formed on the upper side of the piezoelectric body 110 at the same time.

[0112] Therefore, with the above configuration, the multiple films laminated on the piezoelectric body 110 and the metal reflective film 130 can be formed by a simpler process.

[0113] As shown in FIG. 14( b ), optical reflecting element 1 further includes second film 122 formed on the upper surface of metal reflecting film 130 and made of the same material as first film 121 .

[0114] This configuration can increase the reflectance of light incident on the metal reflective film 130 .

[0115] The metal reflective film 130 is made of silver (Ag) or a silver (Ag) alloy, and the first film 121 and the second film 122 are made of alumina (Al ２ O ３ ) or alumina (Al ２ O ３ ) is composed of a mixture of materials.

[0116] According to this configuration, the metal reflective film 130 is made of silver or a silver alloy, and the second film 122 contains alumina, thereby improving the adhesion between the metal reflective film 130 and the second film 122. Furthermore, the first film 121 contains alumina, thereby improving the adhesion between the metal reflective film 130 and the substrate 101. Furthermore, the first film 121 contains alumina, thereby making the upper surface of the piezoelectric body 110 moisture-resistant.

[0117] <Other Modifications> The configuration examples of the present invention are not limited to the above-described embodiment and modifications, and various modifications are possible.

[0118] In the first and third embodiments, either the second film 122 or the third film 123 on the upper side of the metal reflective film 130 may not be formed. In this case, the upper surface of the metal reflective film 130 and the second film 122 or the third film 123 form the reflective surface 11a of the movable part 11. Even when either the second film 122 or the third film 123 is formed on the upper surface of the metal reflective film 130, the metal reflective film 130 can be protected. Furthermore, when either the second film 122 or the third film 123 is formed on the upper surface of the metal reflective film 130, the weight of the movable part region can be reduced compared to the first and third embodiments, allowing the movable part 11 to rotate efficiently.

[0119] In the above embodiment and modified examples, another film may be formed on the top surface of the piezoelectric body 110 in the piezoelectric body region, and another film may be formed on the top surface of the substrate 101 in the movable portion region. Furthermore, the second film 122 and the third film 123 constitute the reflection-enhancing film of the metal reflection film 130 in two layers, but the reflection-enhancing film may also be constituted by a multilayer film of three or more layers.

[0120] In the above embodiment and modified example, the driving unit 12 is a tuning fork type vibrator, but the driving unit 12 may be a vibrator of another type (for example, a meander type vibrator).

[0121] In the above embodiment and modified examples, the shape of the movable portion 11 is circular, but the shape of the movable portion 11 may be other shapes such as square. The shape of the optical reflecting element 1 in a plan view and the dimensions of each part of the optical reflecting element 1 can also be changed as appropriate.

[0122] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical ideas set forth in the claims.

[0123] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0124] (Technology 1) An optical reflecting element in which a movable part is driven by a driving part, comprising: a metal reflecting film arranged in the region of the movable part on a substrate; a piezoelectric body arranged in the region of the driving part on the substrate; a first film formed on the lower surface of the metal reflecting film; a second film formed on the upper surface of the metal reflecting film and made of the same material as the first film; and a protective film formed on the upper side of the piezoelectric body, made of the same material as the first film, and having a thickness substantially the same as the sum of the thicknesses of the first film and the second film.

[0125] The first film is provided to adhere the lower surface of the metal reflective film to the upper surface of the movable part, and the second film is provided to increase the reflectivity beyond that of the metal reflective film itself. Also, a protective film is formed on the upper side of the piezoelectric body to electrically insulate the piezoelectric body from the outside and prevent the intrusion of water vapor, moisture, etc. For these purposes, the protective film on the piezoelectric body side is usually thicker than the first and second films on the metal reflective film side.

[0126] In contrast, according to the above technology, by selecting materials for the first and second films that can simultaneously meet the requirements for both the metal reflective film and the piezoelectric body, in the process of forming the first and second films above and below the metal reflective film, a protective film can be simultaneously formed on the top side of the piezoelectric body by laminating these films together. Furthermore, since this protective film has a thickness that is the sum of the thicknesses of the first and second films, it meets the thickness requirements for the protective film on the piezoelectric body.

[0127] Therefore, according to the above technique, the plurality of films laminated on the piezoelectric body and the metal reflective film can be formed by a simpler process.

[0128] (Technology 2) In the optical reflecting element according to Technology 1, the metal reflective film is made of silver (Ag) or a silver (Ag) alloy, and the first film and the second film are made of alumina (Al ２ O ３ ) or alumina (Al ２ O ３ ) . An optical reflecting element characterized by being composed of a mixture material.

[0129] According to this technology, the metal reflective film is made of silver or a silver alloy, and the second film contains alumina, thereby improving adhesion between the metal reflective film and the second film. Furthermore, the first film contains alumina, thereby improving adhesion between the metal reflective film and the substrate. Furthermore, the protective films (first film and second film) contain alumina, thereby realizing moisture resistance on the top surface of the piezoelectric element.

[0130] (Technology 3) The optical reflecting element according to Technology 1 or 2, further comprising a third film formed on an upper surface of the second film and having a refractive index higher than that of the second film.

[0131] This technique can further increase the reflectance of light incident on the upper surface side of the movable portion.

[0132] (Technology 4) The optical reflecting element according to Technology 3, further comprising another protective film formed on the upper side of the protective film, made of the same material as the third film, and having substantially the same thickness as the third film.

[0133] This technique can improve electrical shielding for the piezoelectric body.

[0134] (Technology 5) In the optical reflecting element according to Technology 3 or 4, the third film is made of zirconia (ZrO ２ ) or the main component is zirconia (ZrO ２ ) . An optical reflecting element characterized by being composed of a mixture material.

[0135] According to this technique, when the second film contains alumina, the refractive index of the third film can be set higher than that of the second film, thereby increasing the light reflectance. In addition, the third film can make the piezoelectric body resistant to warm water.

[0136] (Technology 6) An optical reflecting element in which a movable part is driven by a driving part, comprising: a metal reflecting film arranged in the region of the movable part on a substrate; a piezoelectric body arranged in the region of the driving part on the substrate; a first dielectric film formed on an upper surface of the metal reflecting film; a second dielectric film formed on the upper surface of the first dielectric film and having a refractive index higher than that of the first dielectric film; and at least one of a first protective film formed on the upper side of the piezoelectric body, made of the same material as the first dielectric film and having substantially the same thickness as the first dielectric film, and a second protective film made of the same material as the second dielectric film and having substantially the same thickness as the second dielectric film.

[0137] The first and second dielectric films are provided to increase the reflectance higher than that of the metal reflective film itself. Also, a protective film is formed on the upper side of the piezoelectric body to electrically shield the piezoelectric body from the outside and prevent the intrusion of water vapor, moisture, etc.

[0138] In contrast, according to the above technology, by selecting materials for the first and second dielectric films that can simultaneously meet the requirements of both the metal reflective film and the piezoelectric body, in the process of forming the first and second dielectric films on the upper surface of the metal reflective film, at least one of these films can also be simultaneously formed on the upper side of the piezoelectric body as a protective film.

[0139] Therefore, according to the above technique, the plurality of films laminated on the piezoelectric body and the metal reflective film can be formed by a simpler process.

[0140] (Technology 7) In the optical reflecting element according to Technology 6, the metal reflective film is made of silver (Ag) or a silver (Ag) alloy, and the first dielectric film is made of alumina (Al ２ O ３ ) or alumina (Al ２ O ３) . An optical reflecting element characterized by being composed of a mixture material.

[0141] According to this technology, the metal reflective film is made of silver or a silver alloy, and the first dielectric film contains alumina, thereby improving adhesion between the metal reflective film and the first dielectric film. Furthermore, when the first dielectric film is formed on the upper side of the piezoelectric body, the moisture resistance of the upper surface of the piezoelectric body can be achieved by the first dielectric film containing alumina.

[0142] (Technology 8) In the optical reflecting element according to Technology 6 or 7, the second dielectric film is made of zirconia (ZrO ２ ) or the main component is zirconia (ZrO ２ ) . An optical reflecting element characterized by being composed of a mixture material.

[0143] According to this configuration, when the first dielectric film contains alumina, the refractive index of the second dielectric film can be set higher than the refractive index of the first dielectric film, thereby increasing the light reflectance. Furthermore, when the second dielectric film is formed on the upper side of the piezoelectric body, the second dielectric film contains zirconia, thereby making the upper surface of the piezoelectric body resistant to warm water.

[0144] (Technology 9) An optical reflecting element in which a movable part is driven by a driving part, comprising: a metal reflecting film arranged in the region of the movable part on a substrate; a piezoelectric body arranged in the region of the driving part on the substrate; a first film formed on the underside of the metal reflecting film; and a protective film formed on the upper side of the piezoelectric body, made of the same material as the first film, and having a thickness substantially the same as that of the first film.

[0145] The first film is provided to adhere the lower surface of the metal reflective film to the upper surface of the movable part, and a protective film is formed on the upper side of the piezoelectric body to electrically shield the piezoelectric body from the outside and prevent the intrusion of water vapor, moisture, etc.

[0146] In contrast, according to the above technology, by selecting materials for the first film and the protective film that can simultaneously meet the above requirements on the metal reflective film side and the piezoelectric body side, it is possible to simultaneously form a protective film on the upper side of the piezoelectric body in the process of forming the first film on the lower surface of the metal reflective film.

[0147] Therefore, according to the above technique, the plurality of films laminated on the piezoelectric body and the metal reflective film can be formed by a simpler process.

[0148] (Technology 10) The optical reflecting element according to Technology 9, further comprising a second film formed on an upper surface of the metal reflective film and made of the same material as the first film.

[0149] This technique can increase the reflectance of light incident on the metal reflective film.

[0150] (Technology 11) In the optical reflecting element according to Technology 10, the metal reflective film is made of silver (Ag) or a silver (Ag) alloy, and the first film and the second film are made of alumina (Al ２ O ３ ) or alumina (Al ２ O ３ ) . An optical reflecting element characterized by being composed of a mixture material.

[0151] According to this technology, the metal reflective film is made of silver or a silver alloy, and the second film contains alumina, thereby improving adhesion between the metal reflective film and the second film. Furthermore, the first film contains alumina, thereby improving adhesion between the metal reflective film and the substrate. Furthermore, the first film contains alumina, thereby realizing moisture resistance on the top surface of the piezoelectric body.

[0152] REFERENCE SIGNS LIST 1 Optical reflecting element 11 Movable part 12 Driving part 101 Substrate 110 Piezoelectric body 121 First film (protective film) 122 Second film (first dielectric film, first protective film) 123 Third film (second dielectric film, second protective film, other protective film) 130 Metallic reflective film 140 Protective film

Claims

1. An optical reflecting element in which a movable part is driven by a driving part, comprising: a metal reflective film arranged on a substrate in the region of the movable part; a piezoelectric element arranged on the substrate in the region of the driving part; a first film formed on the underside of the metal reflective film; a second film formed on the upper surface of the metal reflective film and made of the same material as the first film; and a protective film formed on the upper side of the piezoelectric element, made of the same material as the first film, and having a thickness substantially the same as the sum of the thicknesses of the first film and the second film.

2. The optical reflecting element according to claim 1, wherein the metal reflective film is made of silver (Ag) or a silver (Ag) alloy, and the first film and the second film are made of alumina (Al ２ O ３ ) or alumina (Al ２ O ３ ) . An optical reflecting element characterized by being composed of a mixture material.

3. An optical reflecting element according to claim 1 or 2, further comprising a third film formed on the upper surface of said second film and having a refractive index higher than that of said second film.

4. An optical reflecting element according to claim 3, further comprising another protective film formed on the upper side of said protective film, made of the same material as said third film and having substantially the same thickness as said third film.

5. The optical reflecting element according to claim 4, wherein the third film is made of zirconia (ZrO ２ ) or the main component is zirconia (ZrO ２ ) . An optical reflecting element characterized by being composed of a mixture material.

6. An optical reflecting element in which a movable part is driven by a driving part, comprising: a metal reflecting film arranged in the region of the movable part on a substrate; a piezoelectric body arranged in the region of the driving part on the substrate; a first dielectric film formed on the upper surface of the metal reflecting film; a second dielectric film formed on the upper surface of the first dielectric film and having a refractive index higher than that of the first dielectric film; and at least one of a first protective film formed on the upper side of the piezoelectric body, made of the same material as the first dielectric film and having substantially the same thickness as the first dielectric film, and a second protective film made of the same material as the second dielectric film and having substantially the same thickness as the second dielectric film.

7. An optical reflecting element according to claim 6, wherein the metal reflecting film is made of silver (Ag) or a silver (Ag) alloy, and the first dielectric film is made of alumina (Al ２ O ３ ) or alumina (Al ２ O ３ ) . An optical reflecting element characterized by being composed of a mixture material.

8. In the optical reflecting element according to claim 6 or 7, the second dielectric film is made of zirconia (ZrO ２ ) or the main component is zirconia (ZrO ２ ) . An optical reflecting element characterized by being composed of a mixture material.

9. An optical reflecting element in which a movable part is driven by a driving part, comprising: a metal reflective film arranged in the region of the movable part on a substrate; a piezoelectric body arranged in the region of the driving part on the substrate; a first film formed on the underside of the metal reflective film; and a protective film formed on the upper side of the piezoelectric body, made of the same material as the first film and having substantially the same thickness as the first film.

10. An optical reflecting element according to claim 9, further comprising a second film formed on the upper surface of said metal reflecting film and made of the same material as said first film.

11. An optical reflecting element according to claim 10, wherein the metal reflective film is made of silver (Ag) or a silver (Ag) alloy, and the first film and the second film are made of alumina (Al ２ O ３ ) or alumina (Al ２ O ３ ) . An optical reflecting element characterized by being composed of a mixture material.

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