Fabry-perot interference filter

Abstract

This Fabry-Perot interference filter includes a first reflection film, a second reflection film, a movable layer supporting the first reflection film, and a wiring layer laminated on the movable layer on one side in a first direction. The wiring layer includes a substrate and a second electrode. The movable layer includes a light transmission member, a support member, and a semiconductor layer. The semiconductor layer includes an electrode part disposed on the light transmission member, a support part disposed on the support member, and an elastic deformation part connecting the electrode part and the support part. In the semiconductor layer, a recess that opens to the wiring layer side is formed so that the surface of the electrode part and the surface of the elastic deformation part are positioned on the other side in the first direction with respect to a bonding surface of the support part.

Description

Fabry-Perot interference filter

[0001] The present disclosure relates to Fabry-Perot interference filters.

[0002] A Fabry-Perot interference filter is known that includes a first substrate, a second substrate stacked on the first substrate, a third substrate stacked on the second substrate, a first reflective film arranged on the surface of the first substrate facing the second substrate, a second reflective film arranged on the surface of the second substrate facing the first substrate across a space, a first electrode arranged on the surface of the second substrate facing the third substrate, and a second electrode arranged on the surface of the third substrate facing the second substrate across a space, wherein each of the first substrate, the second substrate, and the third substrate are glass substrates, and a portion of the second substrate that supports the second reflective film and the first electrode is configured as a movable part for changing the distance between the first reflective film and the second reflective film (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2013-224995

[0004] In the Fabry-Perot interference filter described above, a recess that opens toward the second substrate is formed in the third substrate so that the first electrode and the second electrode face each other across a space. However, because the third substrate is a glass substrate, it is difficult to accurately form the recess in the third substrate during manufacturing of the Fabry-Perot interference filter. As a result, in the manufactured Fabry-Perot interference filter, the initial distance between the first electrode and the second electrode (the distance between the first electrode and the second electrode when no potential difference is generated between the first electrode and the second electrode) may deviate from the desired value. In addition, because the second substrate is also a glass substrate, it is also difficult to accurately form the recess in the second substrate during manufacturing of the Fabry-Perot interference filter.

[0005] An object of the present disclosure is to provide a Fabry-Perot interference filter in which the initial distance between the first electrode and the second electrode is ensured with high precision.

[0006] A Fabry-Perot interference filter according to one aspect of the present disclosure includes: [1] "a first reflective film; a second reflective film facing the first reflective film across a space in a light-transmitting region; a movable layer including a first electrode, the first reflective film being movable in a first direction in which the first reflective film and the second reflective film face each other, and supporting the first reflective film; and a wiring layer stacked on the movable layer on one side in the first direction, the wiring layer including a substrate and a second electrode disposed on the movable layer side with respect to the substrate and facing the first electrode across a space in the first direction, the movable layer including a light-transmitting member constituting the movable portion, a support member surrounding the light-transmitting region when viewed from the first direction, and a wiring layer stacked on the movable layer on one side in the first direction, the wiring layer including a substrate and a second electrode disposed on the movable layer side with respect to the substrate and facing the first electrode across a space in the first direction, the wiring layer including a light-transmitting member constituting the movable portion, a support member surrounding the light-transmitting region when viewed from the first direction, the wiring layer including a wiring layer stacked on the movable layer on one side in ... wiring layer on one side in the first direction, the wiring layer including a wiring layer stacked on the wiring layer on one side in the first direction, the wiring layer including a wiring layer stacked on the wiring layer on one side in the first direction, the wiring layer including a wiring layer stacked on the wiring layer on one side in the first direction, the wiring layer including a wiring layer stacked on the wiring layer on one side in the first direction, the wiring layer including a wiring layer stack a semiconductor layer disposed on the wiring layer side with respect to a support member, the semiconductor layer being disposed on the light-transmitting member and including an electrode portion on which the first electrode is provided or which is the first electrode, a support portion which surrounds the light-transmitting region when viewed from the first direction and is disposed on the support member, and an elastic deformation portion which connects the electrode portion and the support portion, the semiconductor layer being bonded to the substrate at a bonding surface of the support portion on the wiring layer side, and the semiconductor layer having a recess which opens to the wiring layer side so that a surface of the electrode portion on the wiring layer side and a surface of the elastic deformation portion on the wiring layer side are positioned on the other side in the first direction with respect to the bonding surface of the support portion.

[0007] In the Fabry-Perot interference filter described in [1] above, a semiconductor layer is disposed on the wiring layer side of the light-transmitting member and the support member in the movable layer. The semiconductor layer, including the electrode portion, the support portion, and the elastically deforming portion, is bonded to the substrate of the wiring layer at the bonding surface of the support portion on the wiring layer side. A recess opening toward the wiring layer side is formed in the semiconductor layer so that the surface of the electrode portion on the wiring layer side and the surface of the elastically deforming portion on the wiring layer side are located on the other side in the first direction relative to the bonding surface of the support portion. Here, compared to, for example, a glass substrate, it is possible to form the recess in the semiconductor layer with high precision. Therefore, deviation of the initial distance between the first electrode and the second electrode from the desired value can be suppressed regardless of the material of the substrate of the wiring layer. Therefore, the Fabry-Perot interference filter described in [1] above ensures a high precision initial distance between the first electrode and the second electrode.

[0008] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [2] "the Fabry-Perot interference filter according to the above [1], wherein the substrate is a glass substrate and the semiconductor layer is a silicon layer." According to the Fabry-Perot interference filter according to [2], it is only necessary to form recesses in a silicon substrate, which is easier to process than a glass substrate, and therefore it is possible to more reliably prevent the initial distance between the first electrode and the second electrode from deviating from a desired value.

[0009] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [3] "the Fabry-Perot interference filter according to the above [1] or [2], in which the surface of the substrate on the movable layer side is a flat surface." According to the Fabry-Perot interference filter according to [3], it is possible to prevent the initial distance between the first electrode and the second electrode from deviating from a desired value simply by forming a recess in the semiconductor layer, regardless of the material of the substrate of the wiring layer.

[0010] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [4] "the Fabry-Perot interference filter according to any one of the above [1] to [3], wherein, in a state in which no potential difference is generated between the first electrode and the second electrode, the distance between the first electrode and the second electrode is smaller than the depth of the recess." According to the Fabry-Perot interference filter according to [4], the movable range of the movable part is limited, thereby making it possible to prevent damage to the elastic deformation part.

[0011] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [5] "the Fabry-Perot interference filter according to any one of the above [1] to [4], further comprising a fixed layer that is stacked on the movable layer on the other side in the first direction and supports the second reflective film." According to the Fabry-Perot interference filter according to [5], the movable portion of the movable layer can be protected from both sides by the wiring layer and the fixed layer.

[0012] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [6] "the Fabry-Perot interference filter according to any one of the above [1] to [5], wherein the recess is formed by dry etching." According to the Fabry-Perot interference filter according to [6], the recess is formed with high precision, so that it is possible to more reliably prevent the initial distance between the first electrode and the second electrode from deviating from a desired value.

[0013] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [7] "the Fabry-Perot interference filter according to any one of the above [1] to [6], wherein the side surface of the recess is located outward relative to the inner side surface of the support member when viewed from the first direction." According to the Fabry-Perot interference filter according to [7], even if the position of the recess relative to the support member is slightly shifted, it is possible to prevent the side surface of the recess from becoming displaced from the support member, thereby allowing the elastic deformation portion to function properly. Note that if the side surface of the recess is displaced from the support member, the length of the elastic deformation portion changes, which may prevent the elastic deformation portion from functioning properly.

[0014] According to the present disclosure, it is possible to provide a Fabry-Perot interference filter in which the initial distance between the first electrode and the second electrode is ensured with high precision.

[0015] Fig. 1 is a perspective view of a Fabry-Perot interference filter of one embodiment. Fig. 2 is an exploded perspective view of the Fabry-Perot interference filter shown in Fig. 1. Fig. 3 is an exploded perspective view of the Fabry-Perot interference filter shown in Fig. 1. Fig. 4 is a longitudinal cross-sectional view of the Fabry-Perot interference filter shown in Fig. 1. Fig. 5 is a plan view and a bottom view of the first layer shown in Fig. 1. Fig. 6 is a plan view and a bottom view of the second layer shown in Fig. 1. Fig. 7 is a plan view and a bottom view of the third layer shown in Fig. 1. Fig. 8 is a longitudinal cross-sectional view of a portion of the absorbing film shown in Fig. 1. Fig. 9 is a longitudinal cross-sectional view of a portion of the Fabry-Perot interference filter shown in Fig. 4. Fig. 10 is a longitudinal cross-sectional view of a modified Fabry-Perot interference filter.

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted. [Configuration of Fabry-Perot interference filter]

[0017] As shown in Figures 1, 2, 3, and 4, the Fabry-Perot interference filter 1 includes a first layer (movable layer) 10, a second layer (wiring layer) 20, a third layer (fixed layer) 30, a first reflective film 50, a second reflective film 60, and an absorbing film 70. The first reflective film 50 and the second reflective film 60 face each other across a space. In the following description, the direction in which the first reflective film 50 and the second reflective film 60 face each other (first direction) is referred to as the "Z-axis direction," a direction perpendicular to the Z-axis direction (second direction intersecting with the first direction) is referred to as the "X-axis direction," and a direction perpendicular to both the Z-axis direction and the X-axis direction (third direction intersecting with both the first and second directions) is referred to as the "Y-axis direction." Note that the term "one side" simply refers to one side in the Z-axis direction, and the term "the other side" simply refers to the other side in the Z-axis direction. Furthermore, when simply referring to "thickness," it means the thickness in the Z-axis direction.

[0018] In the Fabry-Perot interference filter 1, the region overlapping both the first reflective film 50 and the second reflective film 60 when viewed from the Z-axis direction functions as the light-transmitting region 1a. The light-transmitting region 1a is a region in which the first reflective film 50 and the second reflective film 60 function as mirrors, transmitting light according to the distance between the first reflective film 50 and the second reflective film 60. As an example, the light-transmitting region 1a is a cylindrical region with a center line that is a straight line L parallel to the Z-axis direction. In the following description, the radial direction of a circle centered on the straight line L when viewed from the Z-axis direction is simply referred to as the "radial direction," and the circumferential direction of the circle is simply referred to as the "circumferential direction." Note that the vertical cross-sectional view of FIG. 4 is a schematic diagram of the Fabry-Perot interference filter 1, and the aspect ratio in FIG. 4 does not match the actual one.

[0019] 4 and 5, the first layer 10 includes a first substrate 11, a semiconductor layer 12, and a metal pad 13. Note that (a) of Fig. 5 is a plan view of the first layer 10, and (b) of Fig. 5 is a bottom view of the first layer 10.

[0020] The first substrate 11 includes a light-transmitting member 14 and a support member 15. The light-transmitting member 14 and the support member 15 are each made of a light-transmitting material such as glass or silicon. As an example, the light-transmitting member 14 and the support member 15 are formed as separate bodies by etching a glass substrate bonded to a silicon substrate that will become the semiconductor layer 12. The glass substrate and the silicon substrate are bonded together using airtight bonding such as room-temperature bonding, plasma activated bonding, or anodic bonding. In the Fabry-Perot interference filter 1, the light-transmitting member 14 and the support member 15, which are made of the same light-transmitting material, constitute the first substrate 11. However, as long as at least the light-transmitting member 14 is made of a light-transmitting material, the light-transmitting member 14 and the support member 15 may be made of different materials.

[0021] The light transmitting member 14 constitutes a part of the light transmitting region 1a. When viewed from the Z-axis direction, the outer edge of the light transmitting member 14 is located outside the outer edge of the light transmitting region 1a. As an example, the light transmitting member 14 is formed in the shape of a circular plate with the straight line L as its center line. The outer diameter of the light transmitting member 14 is, for example, about 4 to 6 mm. The thickness of the light transmitting member 14 is, for example, about 0.2 to 0.5 mm.

[0022] The support member 15 surrounds the light transmitting member 14 when viewed from the Z-axis direction. In other words, the support member 15 surrounds the light transmitting region 1a when viewed from the Z-axis direction. A space is formed between the light transmitting member 14 and the support member 15. The thickness of the support member 15 is approximately equal to the thickness of the light transmitting member 14. As an example, the support member 15 is formed in a rectangular frame shape so as to have a pair of side surfaces perpendicular to the X-axis direction and a pair of side surfaces perpendicular to the Y-axis direction. The width of the support member 15 in each of the X-axis direction and the Y-axis direction is, for example, approximately 11 mm. The thickness of the support member 15 is, for example, approximately 0.2 to 0.5 mm. The width of the space between the light transmitting member 14 and the support member 15 is, for example, approximately 0.5 to 1.5 mm.

[0023] The semiconductor layer 12 is disposed on the second layer 20 side (i.e., one side) of the light transmitting member 14 and the support member 15. The semiconductor layer 12 includes an electrode portion 16, a support portion 17, and a plurality of elastic deformation portions 18. The electrode portion 16, the support portion 17, and the plurality of elastic deformation portions 18 are conductive. The material of each of the electrode portion 16, the support portion 17, and the plurality of elastic deformation portions 18 is, for example, p-type silicon with low resistance (1 Ωcm or less). In other words, the semiconductor layer 12 is a silicon layer. As an example, the electrode portion 16, the support portion 17, and the plurality of elastic deformation portions 18 are integrally formed by etching a silicon substrate bonded to a glass substrate that becomes the first substrate 11.

[0024] The electrode unit 16 surrounds the light-transmitting region 1a when viewed from the Z-axis direction. The electrode unit 16 extends along the outer edge of the light-transmitting member 14 when viewed from the Z-axis direction and is joined to the surface 14a on one side of the light-transmitting member 14. In other words, the electrode unit 16 is disposed on the light-transmitting member 14. When viewed from the Z-axis direction, the outer edge of the electrode unit 16 is located outside the outer edge of the light-transmitting member 14. When viewed from the Z-axis direction, the inner edge of the electrode unit 16 is located inside the outer edge of the light-transmitting member 14 and approximately coincides with the outer edge of the light-transmitting region 1a. As an example, the electrode unit 16 is formed in the shape of a circular frame with the line L as its center line. The inner diameter of the electrode unit 16 is, for example, approximately 3 to 5 mm. The outer diameter of the electrode unit 16 is, for example, approximately 4 to 6 mm. The thickness of the electrode unit 16 is, for example, approximately 30 μm. In the Fabry-Perot interference filter 1, the electrode unit 16 functions as a first electrode 19. That is, the first layer 10 includes a first electrode 19 .

[0025] The support portion 17 surrounds the electrode portion 16 when viewed from the Z-axis direction. That is, the support portion 17 surrounds the light-transmitting region 1a when viewed from the Z-axis direction. A space is formed between the electrode portion 16 and the support portion 17. The support portion 17 is bonded to the surface 15a on one side of the support member 15. That is, the support portion 17 is disposed on the support member 15. In the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, the outer edge of the support portion 17 approximately coincides with the outer edge of the support member 15. When viewed from the Z-axis direction, the inner edge of the support portion 17 is located inside the inner edge of the support member 15. As an example, the support portion 17 is formed in a rectangular frame shape so as to have a pair of side surfaces perpendicular to the X-axis direction and a pair of side surfaces perpendicular to the Y-axis direction. The width of the support portion 17 in each of the X-axis direction and the Y-axis direction is, for example, approximately 11 mm. The thickness of the support portion 17 is, for example, approximately 34 μm. The width of the space between the electrode portion 16 and the support portion 17 is, for example, about 0.5 to 1.5 mm.

[0026] The multiple elastic deformation portions 18 are located between the electrode portion 16 and the support portion 17 and surround the electrode portion 16 when viewed from the Z-axis direction. A space is formed between adjacent pairs of elastic deformation portions 18. Each elastic deformation portion 18 connects the electrode portion 16 and the support portion 17. That is, one end of each elastic deformation portion 18 is connected to the electrode portion 16, and the other end of each elastic deformation portion 18 is connected to the support portion 17. As an example, the multiple elastic deformation portions 18 are arranged at equal angular intervals in the circumferential direction. As an example, each elastic deformation portion 18 is formed in a rectangular plate shape extending in the radial direction. In the Fabry-Perot interference filter 1, the multiple elastic deformation portions 18 are a pair of elastic deformation portions 18 located on both sides of the electrode portion 16 in the X-axis direction and a pair of elastic deformation portions 18 located on both sides of the electrode portion 16 in the Y-axis direction. The width of each elastic deformation portion 18 in the radial direction is, for example, approximately 0.5 to 1.5 mm. The width of each elastic deformation portion 18 in the direction perpendicular to the radial direction is, for example, about 50 μm to 1 mm, and the thickness of each elastic deformation portion 18 is, for example, about 30 μm.

[0027] The thickness of each elastically deforming portion 18 is approximately equal to the thickness of the electrode portion 16. The thickness of the support portion 17 is greater than the thickness of the electrode portion 16 and the thickness of each elastically deforming portion 18, except for an inner edge region along the inner edge of the support portion 17 when viewed from the Z-axis direction. The thickness of the inner edge region of the support portion 17 is approximately equal to the thickness of the electrode portion 16 and the thickness of each elastically deforming portion 18. The surface 16a on one side of the electrode portion 16, the surface 18a on one side of each elastically deforming portion 18, and the surface 17c on one side of the inner edge region of the support portion 17 are continuous. The surface 16a of the electrode portion 16, the surface 18a of each elastically deforming portion 18, and the surface 17c of the inner edge region of the support portion 17 are lower than the surface 17a on one side of the support portion 17. That is, the surface 16a of the electrode portion 16, the surface 18a of each elastically deforming portion 18, and the surface 17c of the inner edge region of the support portion 17 are located on the other side of the surface 17a of one side of the support portion 17. The surface 16b of the other side of the electrode portion 16, the surface 18b of the other side of each elastically deforming portion 18, and the surface 17b of the other side of the support portion 17 are continuous. The electrode portion 16 has a plurality of notches 16c that open outward on both sides (both sides in the circumferential direction) of one end of each elastically deforming portion 18. The support portion 17, including the inner region having the surface 17c, is joined to the surface 15a of the support member 15.

[0028] The metal pad 13 is formed on the surface 17a of the support portion 17. The metal pad 13 is electrically connected to the electrode portion 16, which is the first electrode 19, via the semiconductor layer 12 as wiring. In other words, the semiconductor layer 12 functions as a wiring layer that electrically connects the first electrode 19 and the metal pad 13. As an example, the metal pad 13 is formed in the shape of a rectangular film extending along one side of the outer edge of the surface 17a that is parallel to the Y-axis direction. The material of the metal pad 13 is, for example, a metal material such as Al. The width of the metal pad 13 in the X-axis direction is, for example, approximately 0.1 to 1 mm. The width of the metal pad 13 in the Y-axis direction is, for example, approximately 0.1 to 8 mm. The thickness of the metal pad 13 is, for example, approximately 1 μm.

[0029] In the first substrate 11 and semiconductor layer 12 configured as described above, the movable portion 10a is configured by the light transmitting member 14 and the electrode portion 16. The movable portion 10a is a portion that overlaps with the light transmitting region 1a, and is movable in the Z-axis direction by deformation of the multiple elastic deformation portions 18. In other words, the first layer 10 is a movable layer in which the portion that overlaps with the light transmitting region 1a is configured as the movable portion 10a that is movable in the Z-axis direction.

[0030] The first reflective film 50 is disposed on the other surface 14b of the light transmitting member 14. That is, the first layer 10 supports the first reflective film 50 at the movable portion 10a. The first reflective film 50 is movable in the Z-axis direction together with the movable portion 10a. As an example, the first reflective film 50 is formed in the shape of a circular film with the straight line L as its center line. The first reflective film 50 is formed, for example, by forming a dielectric film made of aluminum oxide or the like on the surface opposite the surface 14b of a metal film made of Ag or the like. The outer diameter of the first reflective film 50 is, for example, approximately 4 to 6 mm. The thickness of the first reflective film 50 is, for example, approximately 210 nm. The first reflective film 50 may be formed solely of a metal film made of Ag or the like, or solely of a dielectric film made of silicon oxide, titanium oxide, aluminum oxide, or the like, or may be formed by stacking a plurality of such dielectric films.

[0031] 4 and 6 , the second layer 20 is stacked on one side of the first layer 10. The second layer 20 includes a second substrate (substrate) 21, a plurality of second electrodes 22, a light-shielding film 23, a plurality of third electrodes 24, a plurality of electrode pads 25, and a plurality of through-electrodes 26. Note that (a) of FIG. 6 is a plan view of the second layer 20, and (b) of FIG. 6 is a bottom view of the second layer 20.

[0032] The second substrate 21 constitutes a part of the light-transmitting region 1a. The second substrate 21 has a surface 21a on one side and a surface 21b on the other side. The surface 21a is the surface opposite the first layer 10, and the surface 21b is the surface on the first layer 10 side. The surface 21b of the second substrate 21 is bonded to the surface 17a of the support portion 17 and is spaced apart from the surface 16a of the electrode portion 16, the surface 18a of each elastic deformation portion 18, and the surface 17c of the inner edge region of the support portion 17. The thickness of the second substrate 21 is greater than the thickness of the semiconductor layer 12. As an example, the second substrate 21 is formed in a rectangular plate shape having a pair of side surfaces perpendicular to the X-axis direction and a pair of side surfaces perpendicular to the Y-axis direction. In the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, the outer edge of the second substrate 21 substantially coincides with the outer edge of the support portion 17, except for a notch 210 described below. The second substrate 21 is a glass substrate. The width of the second substrate 21 in each of the X-axis direction and the Y-axis direction is, for example, approximately 11 mm. The thickness of the second substrate 21 is, for example, approximately 0.5 mm. The support portion 17 and the second substrate 21 are joined together by airtight bonding such as room temperature bonding, plasma activated bonding, or anodic bonding.

[0033] A notch 210 is formed in the second substrate 21. The notch 210 opens on the opposite side of the light-transmitting region 1a in the X-axis direction, exposing the metal pad 13 to the outside. The notch 210 has a first side surface 210a and a pair of second side surfaces 210b. The first side surface 210a faces outward in the X-axis direction. The pair of second side surfaces 210b face each other in the Y-axis direction. Rounded chamfered surfaces 210c are formed at the corners between the first side surface 210a and each of the second side surfaces 210b. The width of the notch 210 in the X-axis direction is, for example, approximately 1 mm. The width of the notch 210 in the Y-axis direction is, for example, approximately 1 to 10 mm.

[0034] The second electrodes 22 are disposed on the surface 21b of the second substrate 21. That is, the second electrodes 22 are disposed on the first layer 10 side of the second substrate 21. The second electrodes 22 surround the light-transmitting region 1a when viewed from the Z-axis direction and face the electrode portion 16 (i.e., the first electrodes 19) across a space in the Z-axis direction. As an example, the second electrodes 22 are arranged at equal angular intervals in the circumferential direction, and a slit-like gap extending in the radial direction is formed between a pair of adjacent second electrodes 22. As an example, each second electrode 22 is formed in the shape of a film extending in the circumferential direction. The material of each second electrode 22 is, for example, a metal material such as Au. The width of each second electrode 22 in the radial direction is, for example, approximately 1 mm. The width of each second electrode 22 in the circumferential direction is, for example, the value obtained by dividing the length of the circumference by the number of second electrodes 22 when multiple second electrodes 22 are lined up along the circumference. For example, when four second electrodes 22 are lined up along the circumference with a diameter of 5 mm, the width is approximately 4 mm. The thickness of each second electrode 22 is, for example, approximately 1 to 5 μm. The width of the gap between a pair of adjacent second electrodes 22 is, for example, approximately 0.1 mm. The initial distance between the electrode portion 16 (i.e., the first electrode 19) and each second electrode 22 (the distance between the first electrode 19 and each second electrode 22 when no potential difference is generated between the first electrode 19 and each second electrode 22) is, for example, approximately 3 μm.

[0035] In the Fabry-Perot interference filter 1, the multiple second electrodes 22 include a pair of second electrodes 22 located on both sides of the light-transmitting region 1a in the X-axis direction and a pair of second electrodes 22 located on both sides of the light-transmitting region 1a in the Y-axis direction. Each second electrode 22 includes a main body 22a and a pair of protrusions 22b. The main body 22a extends in the circumferential direction and faces the first electrode 19 across a space in the Z-axis direction. The pair of protrusions 22b protrude radially outward from the main body 22a and are located on both sides of the elastic deformation portion 18 in the circumferential direction when viewed from the Z-axis direction (see FIG. 5 ). The main body 22a has a notch 22c formed between the pair of protrusions 22b that opens outward. When viewed from the Z-axis direction, the notch 22c overlaps one end of the elastic deformation portion 18 and the pair of notches 16c on both sides of it (see FIG. 5 ).

[0036] The light-shielding film 23 is disposed on the surface 21a of the second substrate 21. That is, the light-shielding film 23 is formed on one side of the second layer 20. The light-shielding film 23 is a first metal film 27 that surrounds the light-transmitting region 1a when viewed from the Z-axis direction. The light-shielding film 23 extends along the outer edge of the light-transmitting region 1a when viewed from the Z-axis direction. In the Fabry-Perot interference filter 1, the light-shielding film 23 extends in an annular shape along the outer edge of the light-transmitting region 1a when viewed from the Z-axis direction. The light-shielding film 23 has an opening 23a that overlaps with the light-transmitting region 1a when viewed from the Z-axis direction. The material of the light-shielding film 23 is, for example, a metal material such as Au. The inner diameter of the light-shielding film 23 (i.e., the diameter of the opening 23a) is, for example, approximately 3 to 5 mm. The outer diameter of the light-shielding film 23 is, for example, approximately 5 to 7 mm. The thickness of the light-shielding film 23 is, for example, about 1 to 5 μm. The light-shielding film 23 (that is, the first metal film 27) does not function as an electrode or wiring.

[0037] The plurality of third electrodes 24 are disposed on the surface 21a of the second substrate 21. The plurality of third electrodes 24 are a plurality of second metal films 28 surrounding the first metal film 27 when viewed from the Z-axis direction. In other words, the plurality of third electrodes 24 surround the light-transmitting region 1a when viewed from the Z-axis direction. As an example, the plurality of third electrodes 24 are arranged circumferentially at equal angular intervals, and a slit-like gap extending in the radial direction is formed between a pair of adjacent third electrodes 24. As an example, each third electrode 24 is formed in the shape of a film extending in the circumferential direction, and a slit-like gap extending in the circumferential direction is formed between the light-shielding film 23 and each third electrode 24. The material of each third electrode 24 is, for example, a metal material such as Au. The radial width of each third electrode 24 is, for example, approximately 1 mm. The width of each third electrode 24 in the circumferential direction is, for example, the value obtained by dividing the length of the circumference by the number of third electrodes 24 when multiple third electrodes 24 are lined up along the circumference; for example, when four third electrodes 24 are lined up along the circumference with a diameter of 5 mm, the width is approximately 4 mm. The thickness of each third electrode 24 is, for example, approximately 1 to 5 μm. The width of the gap between a pair of adjacent third electrodes 24 is, for example, approximately 0.1 mm. The width of the gap between the light-shielding film 23 and each third electrode 24 is, for example, approximately 0.1 mm.

[0038] In the Fabry-Perot interference filter 1, the multiple third electrodes 24 are a pair of third electrodes 24 located on both sides of the light-shielding film 23 in the X-axis direction, and a pair of third electrodes 24 located on both sides of the light-shielding film 23 in the Y-axis direction. When viewed from the Z-axis direction, each third electrode 24 is located radially outward from the main body 22a of each second electrode 22. When viewed from the Z-axis direction, each third electrode 24 overlaps with a pair of protrusions 22b of each second electrode 22.

[0039] The electrode pads 25, together with the wirings 25a, are arranged on the surface 21a of the second substrate 21. Each third electrode 24 is electrically connected to each electrode pad 25 via each wiring 25a. In the Fabry-Perot interference filter 1, each electrode pad 25 is arranged at each of the four corners of the rectangular surface 21a and is formed in the shape of a circular film. Each wiring 25a connects one end of the third electrode 24 in the circumferential direction to the electrode pad 25 for the corresponding third electrode 24 and electrode pad 25. The material of each electrode pad 25 and each wiring 25a is, for example, a metal material such as Au. The outer diameter of each electrode pad 25 is, for example, approximately 0.5 to 1 mm. The width of each wiring 25a is, for example, approximately 0.1 to 0.5 mm. The thickness of each electrode pad 25 and each wiring 25a is, for example, approximately 1 to 5 μm.

[0040] In the Fabry-Perot interference filter 1, the light-shielding film 23 and the plurality of third electrodes 24 are formed of the same material. That is, the first metal film 27 and the plurality of second metal films 28 are formed of the same material. The plurality of electrode pads 25 and the plurality of wirings 25 a are formed integrally with the plurality of third electrodes 24 from the same material as the first metal film 27 and the second metal film 28.

[0041] A plurality of through electrodes 26 are provided on the second substrate 21. The plurality of through electrodes 26 are disposed in a plurality of through holes formed in the second substrate 21 so as to extend in the Z-axis direction and open to the surface 21a and the surface 21b, thereby airtightly sealing the plurality of through holes. Each second electrode 22 is electrically connected to a corresponding third electrode 24 via at least two of the plurality of through electrodes 26. In the Fabry-Perot interference filter 1, each through electrode 26 connects the protrusion 22b of the second electrode 22 to the corresponding third electrode 24 in the corresponding second electrode 22 and the corresponding third electrode 24. That is, in the corresponding second electrode 22 and the corresponding third electrode 24, the second electrode 22 is electrically connected to the third electrode 24 via two through electrodes 26. Each through electrode 26 is made of a metal material such as Au. The length of each through electrode 26 in the Z-axis direction is, for example, approximately 0.5 mm. The width of each through electrode 26 in the direction perpendicular to the Z-axis direction is, for example, about 0.1 mm. The plurality of through electrodes 26 do not necessarily need to airtightly close the plurality of through holes formed in the second substrate 21.

[0042] 4 and 7 , the third layer 30 is stacked on the other side of the first layer 10. The third layer 30 includes a third substrate 31 and a plurality of protrusions 32. Note that (a) of Fig. 7 is a plan view of the third layer 30, and (b) of Fig. 7 is a bottom view of the third layer 30.

[0043] The third substrate 31 constitutes a part of the light-transmitting region 1a. The third substrate 31 has a surface 31a on one side and a surface 31b on the other side. The surface 31a is the surface on the first layer 10 side, and the surface 31b is the surface opposite the first layer 10. The surface 31a of the third substrate 31 is bonded to the surface 15b on the other side of the support member 15. The thickness of the third substrate 31 is greater than the thickness of the semiconductor layer 12. As an example, the third substrate 31 is formed in a rectangular plate shape so as to have a pair of side surfaces perpendicular to the X-axis direction and a pair of side surfaces perpendicular to the Y-axis direction. In the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, the outer edge of the third substrate 31 approximately coincides with the outer edge of the support member 15. The third substrate 31 is a glass substrate. The width of the third substrate 31 in each of the X-axis direction and the Y-axis direction is, for example, approximately 11 mm. The thickness of the third substrate 31 is, for example, approximately 0.5 mm. The support member 15 and the third substrate 31 are joined together by airtight bonding such as room temperature bonding, plasma activated bonding, or metal diffusion bonding.

[0044] The plurality of protrusions 32 are arranged on the surface 31a of the third substrate 31. When viewed from the Z-axis direction, the plurality of protrusions 32 surround the light-transmitting region 1a and face a region of the first reflective film 50 located outside the light-transmitting region 1a in the Z-axis direction. As an example, each protrusion 32 is formed in a cylindrical shape. The material of each protrusion 32 is, for example, silicon oxide, silicon nitride, or the like. The outer diameter of each protrusion 32 is, for example, approximately 0.1 mm. The height of each protrusion 32 in the Z-axis direction is, for example, approximately 50 nm.

[0045] The second reflective film 60 is disposed on the surface 31a of the third substrate 31. In other words, the third layer 30 supports the second reflective film 60. The region of the second reflective film 60 located outside the light-transmitting region 1a covers the multiple convex portions 32. As an example, the second reflective film 60 is formed in a circular shape with the straight line L as its center line. In the Fabry-Perot interference filter 1, when no potential difference is generated between the first electrode 19 and each second electrode 22, the portion of the second reflective film 60 located on each convex portion 32 contacts the region of the first reflective film 50 located outside the light-transmitting region 1a. This forms a space between the first reflective film 50 and the second reflective film 60 in the light-transmitting region 1a, preventing surface contact between the first reflective film 50 and the second reflective film 60. The second reflective film 60 is configured, for example, by forming a dielectric film made of aluminum oxide or the like on the surface opposite the surface 14b of a metal film made of Ag or the like. The outer diameter of the second reflective film 60 is, for example, about 5 to 8 mm. The thickness of the second reflective film 60 is, for example, about 210 nm. When no potential difference is generated between the first electrode 19 and each second electrode 22, the distance between the first reflective film 50 and the second reflective film 60 in the light-transmitting region 1a is, for example, about 50 nm. The second reflective film 60 may be composed only of a metal film made of Ag or the like, or may be composed only of a dielectric film made of silicon oxide, titanium oxide, aluminum oxide, or the like, or may be composed of a plurality of such dielectric films stacked together.

[0046] The absorbing film 70 is disposed on the surface 31b of the third substrate 31. That is, the absorbing film 70 is located on the other side of the first reflective film 50 and the second reflective film 60. One surface 70a of the absorbing film 70 has light absorption properties, and the other surface 70b of the absorbing film 70 has light reflection properties. The absorbing film 70 surrounds the light-transmitting region 1a when viewed from the Z-axis direction. The absorbing film 70 has an opening 70c that overlaps with the light-transmitting region 1a when viewed from the Z-axis direction. In the Fabry-Perot interference filter 1, the outer edge of the absorbing film 70 approximately coincides with the outer edge of the third substrate 31 when viewed from the Z-axis direction. The diameter of the opening 70c is, for example, approximately 3 to 5 mm.

[0047] As shown in FIG. 8 , the absorption film 70 has a multilayer structure including a reflective layer 71, a resonant layer 72, and an absorbing layer 73. The reflective layer 71, the resonant layer 72, and the absorbing layer 73 are stacked in this order from the side opposite the third substrate 31. That is, the resonant layer 72 is disposed between the reflective layer 71 and the third substrate 31, and the absorbing layer 73 is disposed between the resonant layer 72 and the third substrate 31. The reflective layer 71 is a metal layer that does not transmit light incident on one surface 70 a (at least light in the wavelength band that transmits through the first reflective film 50 and the second reflective film 60, the distance between which is variable). At the wavelength of light incident on the one surface 70 a, the optical transmittance inside the resonant layer 72 is greater than the optical transmittance inside the absorbing layer 73. At the wavelength of light incident on the one surface 70 a, the optical reflectance of the surface of the reflective layer 71 is greater than the optical reflectance of the surface of the resonant layer 72. The absorption film 70 thus configured has a surface 70a on one side that is light absorbing and a surface 70b on the other side that is light reflective. The material of the reflective layer 71 is, for example, a metal material such as Cr, Ti, or Al. The thickness of the reflective layer 71 is, for example, 100 nm or more. The material of the resonant layer 72 is, for example, SiO ２ The resonant layer 72 is made of a dielectric material such as silicon dioxide. The thickness of the resonant layer 72 is, for example, within a range of ±20% centered on an integral multiple of one-fourth of the wavelength of light incident on one surface 70a (a reference wavelength such as the central wavelength). The material of the absorption layer 73 is, for example, a metal material such as Cr or Ti, or a silicide. The thickness of the absorption layer 73 is, for example, about 1 to 10 nm.

[0048] In the Fabry-Perot interference filter 1 configured as described above, when a voltage is applied to the first electrode 19 and the plurality of second electrodes 22 via the metal pad 13 and the plurality of electrode pads 25, a potential difference is generated between the first electrode 19 and the plurality of second electrodes 22, and an electrostatic force corresponding to the potential difference is generated between the first electrode 19 and the plurality of second electrodes 22. The generation of the electrostatic force between the first electrode 19 and the plurality of second electrodes 22 moves the movable part 10a to one side, changing the distance between the first reflective film 50 and the second reflective film 60. Here, the wavelength of light passing through the light transmission region 1a of the Fabry-Perot interference filter 1 depends on the distance between the first reflective film 50 and the second reflective film 60. Therefore, by adjusting the voltage applied to the first electrode 19 and the plurality of second electrodes 22 (i.e., the potential difference generated between the first electrode 19 and the plurality of second electrodes 22), the wavelength of light passing through the Fabry-Perot interference filter 1 can be selected. In the Fabry-Perot interference filter 1, the first substrate 11, the semiconductor layer 12, the second substrate 21, and the third substrate 31 are airtightly joined together, and the plurality of through holes formed in the second substrate 21 are airtightly blocked by the plurality of through electrodes 26, so that the movable part 10a moves in the Z-axis direction in the airtight space. [Configuration of the First Semiconductor Layer]

[0049] As described above, the semiconductor layer 12 of the first layer 10 is a silicon layer, and the second substrate 21 of the second layer 20 is a glass substrate. As shown in Figures 4 and 9, the surface 16a of the electrode portion 16, the surface 18a of each elastic deformation portion 18, and the surface 17c of the inner edge region of the support portion 17 are located on the other side of the surface 17a of the support portion 17. In other words, the semiconductor layer 12 has a recess 120 that opens into the second layer 20 so that the surface 16a of the electrode portion 16 and the surface 18a of each elastic deformation portion 18 are located on the other side of the surface 17a of the support portion 17. In the Fabry-Perot interference filter 1, the side surface 121 of the recess 120 is a step surface (a surface perpendicular to the surfaces 17a and 17c) between the surface 17a of the support portion 17 and the surface 17c of the inner edge region of the support portion 17, and the bottom surface 122 of the recess 120 is a surface including the surface 16a of the electrode portion 16, the surface 18a of each elastic deformation portion 18, and the surface 17c of the inner edge region of the support portion 17. When viewed from the Z-axis direction, the side surface 121 of the recess 120 is located on the surface 17a of the support portion 17 and is located outside the inner side surface 15c of the support member 15 (the side from the center of the Fabry-Perot interference filter 1 toward the outer edge of the Fabry-Perot interference filter 1 when viewed from the Z-axis direction, i.e., the outer side in the radial direction of the Fabry-Perot interference filter 1). The recess 120 as described above is formed by dry etching a silicon substrate that will become the semiconductor layer 12. In other words, the recess 120 is a recess formed by dry etching.

[0050] The semiconductor layer 12 is bonded to the second substrate 21 at the surface (bonding surface) 17a of the support portion 17. More specifically, the semiconductor layer 12 is bonded to the second substrate 21 by bonding the surface 17a of the support portion 17 and the surface 21b of the second substrate 21 to each other. The surface 21b of the second substrate 21 is a flat surface. The surface of the second substrate 21 facing the other side (a surface perpendicular to the thickness direction of the second substrate 21) is configured as a flat surface, and this surface facing the other side is the surface 21b. The initial distance d1 between the first electrode 19 (i.e., the electrode portion 16) and each second electrode 22 (the distance between the first electrode 19 and each second electrode 22 when no potential difference is generated between the first electrode 19 and each second electrode 22) is smaller than the depth d2 of the recess 120 (the distance between the surface 17a of the support portion 17 and the surface 17c of the inner edge region of the support portion 17 in the Z-axis direction). The initial distance d1 between the first electrode 19 and each second electrode 22 is, for example, about 3 μm, and the depth d2 of the recess 120 is, for example, about 4 μm. In the Fabry-Perot interference filter 1, when no potential difference is generated between the first electrode 19 and each second electrode 22, the light transmitting member 14 moves toward the second layer 20 relative to the support member 15 by an amount equal to the sum of the thickness of the first reflective film 50, the thickness of the second reflective film 60, and the height of the protrusion 32. Therefore, the initial distance d1 between the first electrode 19 and each second electrode 22 is smaller than the depth d2 of the recess 120. [Operation and Effects]

[0051] In the Fabry-Perot interference filter 1, the semiconductor layer 12 is disposed in the first layer 10 on the second layer 20 side relative to the light transmitting member 14 and the support member 15. The semiconductor layer 12, which includes the electrode portion 16, the support portion 17, and a plurality of elastic deformation portions 18, is bonded to the second substrate 21 of the second layer 20 at the surface 17a of the support portion 17. A recess 120 opening toward the second layer 20 side is formed in the semiconductor layer 12 so that the surface 16a of the electrode portion 16 and the surface 18a of each elastic deformation portion 18 are located on the other side of the surface 17a of the support portion 17. Here, compared to, for example, a glass substrate, it is possible to form the recess 120 with greater precision in the semiconductor layer 12. Therefore, regardless of the material of the second substrate 21 of the second layer 20, deviation of the initial distance d1 between the first electrode 19 and each second electrode 22 from a desired value can be suppressed. Therefore, in the Fabry-Perot interference filter 1, the initial distance d1 between the first electrode 19 and each second electrode 22 is ensured with high precision.

[0052] In the Fabry-Perot interference filter 1, the recesses 120 can be formed, for example, as follows: That is, the second electrodes 22 are formed on the surface 21b of the second substrate 21, the thickness of the formed second electrodes 22 is measured, the depth of the recesses 120 is determined based on the measured thickness, and the recesses 120 are formed in the semiconductor layer 12 to the determined depth. This makes it possible to obtain a Fabry-Perot interference filter 1 in which the initial distance d1 between the first electrodes 19 and the second electrodes 22 is accurately ensured, even when the thickness of the formed second electrodes 22 varies. Compared to, for example, a glass substrate, it is possible to form the recesses 120 accurately in the semiconductor layer 12, and therefore, forming the recesses 120 as described above is particularly effective in accurately ensuring the initial distance d1 between the first electrodes 19 and each second electrode 22. Furthermore, when the second electrode 22 is formed on the surface 21b of the second substrate 21 by plating, the thickness of the second electrode 22 is likely to vary, so forming the recess 120 as described above is particularly effective in accurately ensuring the initial distance d1 between the first electrode 19 and each second electrode 22.

[0053] In the Fabry-Perot interference filter 1, the second substrate 21 is a glass substrate, and the semiconductor layer 12 is a silicon layer. In this case, the recesses 120 can be formed in a silicon substrate, which is easier to process than a glass substrate, and therefore, it is possible to more reliably prevent the initial distance d1 between the first electrode 19 and each second electrode 22 from deviating from a desired value.

[0054] In the Fabry-Perot interference filter 1, the surface 21b of the second substrate 21 is a flat surface. In this case, regardless of the material of the second substrate 21 of the second layer 20, simply forming the recesses 120 in the semiconductor layer 12 can prevent the initial distance d1 between the first electrode 19 and each second electrode 22 from deviating from a desired value.

[0055] In the Fabry-Perot interference filter 1, the initial distance d1 between the first electrode 19 and each second electrode 22 is smaller than the depth d2 of the recess 120. This limits the movable range of the movable portion 10a, thereby preventing damage to each elastic deformation portion 18.

[0056] In the Fabry-Perot interference filter 1, the third layer 30 stacked on the other side of the first layer 10 supports the second reflective film 60. This allows the movable part 10a of the first layer 10 to be protected from both sides by the second layer 20 and the third layer 30.

[0057] In the Fabry-Perot interference filter 1, the recesses 120 are recesses formed by dry etching. In this case, the recesses 120 are formed with high precision, so that it is possible to more reliably prevent the initial distance d1 between the first electrode 19 and each second electrode 22 from deviating from a desired value.

[0058] In the Fabry-Perot interference filter 1, the side surface 121 of the recess 120 is located outward of the inner side surface 15c of the support member 15 when viewed from the Z-axis direction. This prevents the side surface 121 of the recess 120 from being displaced from the support member 15, allowing each elastic deformation portion 18 to function properly, even if the position of the recess 120 relative to the support member 15 is slightly shifted. If the side surface 121 of the recess 120 is displaced from the support member 15, the length of each elastic deformation portion 18 will change, which may prevent each elastic deformation portion 18 from functioning properly.

[0059] In the Fabry-Perot interference filter 1, the support portion 17 of the semiconductor layer 12, including the inner region having the surface 17c, is bonded to the surface 15a of the support member 15. This makes it possible to suppress changes in the length of each elastic deformation portion 18 even if the position of the recess 120 relative to the support member 15 is slightly shifted, and allows each elastic deformation portion 18 to function appropriately. [Modification]

[0060] The present disclosure is not limited to the above-described embodiment. For example, the second substrate 21 is not limited to a glass substrate and may be a substrate made of an optically transparent material other than glass (e.g., silicon). Similarly, the third substrate 31 is not limited to a glass substrate and may be a substrate made of an optically transparent material other than glass (e.g., silicon). Furthermore, the semiconductor layer 12 is not limited to a silicon layer and may be a layer made of a semiconductor material other than silicon. Even in this case, it is possible to form the recess 120 in the semiconductor layer 12 with higher accuracy than in the case of, for example, a glass substrate.

[0061] The surface 21b of the second substrate 21 is not limited to a flat surface, and may have, for example, a recess formed on the surface 21b of the second substrate 21 that is open to the first layer 10, with the second electrode 22 disposed on the bottom surface of the recess. Even in this case, for example, by determining the depth of the recess 120 according to the depth of the recess and the thickness of the second electrode 22 and forming the recess 120 in the semiconductor layer 12 to have the determined depth, it is possible to obtain a Fabry-Perot interference filter 1 in which the initial distance d1 between the first electrode 19 and the second electrode 22 is ensured with high precision, even when the depth of the recess of the second substrate 21 and the thickness of the second electrode 22 vary.

[0062] The initial distance d1 between the first electrode 19 and the second electrode 22 may be equal to or greater than the depth d2 of the recess 120. As described above, when a recess that opens to the first layer 10 side is formed on the surface 21b of the second substrate 21 and the second electrode 22 is disposed on the bottom surface of the recess, the initial distance d1 can be equal to or greater than the depth d2.

[0063] The third layer 30 may not be stacked on the first layer 10 on the other side of the first layer 10, and the second layer 20 may support the second reflective film 60. In that case, for example, the first reflective film 50 is disposed on the surface 14a of the light transmitting member 14 inside the first electrode 19, and the second reflective film 60 is disposed on the surface 21b of the second substrate 21 inside the second electrode 22.

[0064] The recess 120 is not limited to a recess formed by dry etching, and may be a recess formed by other methods. Furthermore, the side surface 121 of the recess 120 may coincide with the inner side surface 15 c of the support member 15 when viewed from the Z-axis direction, or may be located more inward than the inner side surface 15 c of the support member 15 when viewed from the Z-axis direction.

[0065] The second layer 20 may include one second electrode 22 facing the first electrode 19 across a space in the Z-axis direction, and one second metal film 28 surrounding the first metal film 27 when viewed from the Z-axis direction. In this case, one second electrode 22 may be electrically connected to one second metal film 28 via at least one through electrode 26. In other words, the second layer 20 may include one third electrode 24 surrounding the light-shielding film 23 when viewed from the Z-axis direction.

[0066] The second layer 20 may include a plurality of first metal films 27 surrounding the light-transmitting region 1 a when viewed from the Z-axis direction. In this case, each second electrode 22 may be electrically connected to each first metal film 27 via at least one through electrode 26. The second layer 20 may also include one second electrode 22 facing the first electrode 19 across a space in the Z-axis direction, and one first metal film 27 surrounding the light-transmitting region 1 a when viewed from the Z-axis direction. In this case, one second electrode 22 may be electrically connected to one first metal film 27 via at least one through electrode 26. As described above, in the second layer 20, the first metal film 27 may be configured as the third electrode 24, and the second metal film 28 may be configured as the light-shielding film 23.

[0067] The first electrode 19 may be provided on the electrode unit 16. As an example, as shown in Fig. 10 , the first electrode 19 may be disposed on one surface of the electrode unit 16. In the example shown in Fig. 10 , the first electrode 19 is a single electrode that surrounds the light-transmitting region 1a when viewed from the Z-axis direction, and faces a plurality of second electrodes 22 across spaces in the Z-axis direction.

[0068] The second layer 20 may further include a fourth electrode disposed on the surface 21 a of the second substrate 21. In this case, the fourth electrode may be electrically connected to the first electrode 19 via at least one through electrode 26.

[0069] The first layer 10 includes a plurality of first electrodes 19 surrounding the light-transmitting region 1 a when viewed from the Z-axis direction, and the second layer 20 may further include a plurality of fourth electrodes surrounding the light-transmitting region 1 a when viewed from the Z-axis direction. In this case, each of the first electrodes 19 may be electrically connected to each of the fourth electrodes via at least one through electrode 26. This allows, for example, fine adjustment of the potential applied to each of the first electrodes 19 and fine adjustment of the potential applied to each of the second electrodes 22 so that the first reflective film 50 and the second reflective film 60 are parallel to each other.

[0070] At least one third metal film surrounding the second metal film 28 may be disposed on the surface 21 a of the second substrate 21. In this case, similar to the light-shielding film 23, the at least one third metal film can function as a light-shielding film.

[0071] 1...Fabry-Perot interference filter, 1a...light-transmitting region, 10...first layer (movable layer), 10a...movable portion, 12...semiconductor layer, 14...light-transmitting member, 15...support member, 15c...side surface, 16...electrode portion, 16a...surface, 17...support portion, 17a...surface (bonding surface), 18...elastically deforming portion, 18a...surface, 19...first electrode, 20...second layer (wiring layer), 21...second substrate (substrate), 21b...surface, 22...second electrode, 30...third layer (fixed layer), 50...first reflective film, 60...second reflective film, 120...recess, 121...side surface.

Claims

1. A light-transmitting element comprising: a first reflective film; a second reflective film facing the first reflective film across a space in a light-transmitting region; a movable layer including a first electrode and supporting the first reflective film in a movable section movable in a first direction in which the first reflective film and the second reflective film face each other; and a wiring layer stacked on the movable layer on one side in the first direction, wherein the wiring layer includes: a substrate; and a second electrode that is disposed on the movable layer side with respect to the substrate and faces the first electrode across a space in the first direction, wherein the movable layer includes: a light-transmitting member that constitutes the movable section; a support member that surrounds the light-transmitting region when viewed from the first direction; and a semiconductor layer that is disposed on the wiring layer side with respect to the light-transmitting member and the support member, wherein the semiconductor layer is disposed on the light-transmitting member and includes: an electrode section on which the first electrode is provided or which is the first electrode; and a support section that surrounds the light-transmitting region when viewed from the first direction and is disposed on the support member. an elastic deformation portion connecting the electrode portion and the support portion, the semiconductor layer being bonded to the substrate at a bonding surface of the support portion facing the wiring layer, and the semiconductor layer being formed with a recess opening toward the wiring layer side such that the surface of the electrode portion facing the wiring layer and the surface of the elastic deformation portion facing the wiring layer are positioned on the other side in the first direction relative to the bonding surface of the support portion.

2. The Fabry-Perot interference filter according to claim 1, wherein the substrate is a glass substrate, and the semiconductor layer is a silicon layer.

3. The Fabry-Perot interference filter according to claim 1 or 2, wherein the surface of the substrate facing the movable layer is a flat surface.

4. A Fabry-Perot interference filter according to any one of claims 1 to 3, wherein when no potential difference is generated between the first electrode and the second electrode, the distance between the first electrode and the second electrode is smaller than the depth of the recess.

5. A Fabry-Perot interference filter according to any one of claims 1 to 4, further comprising a fixed layer stacked on the movable layer on the other side in the first direction and supporting the second reflective film.

6. The Fabry-Perot interference filter according to any one of claims 1 to 5, wherein the recess is a recess formed by dry etching.

7. A Fabry-Perot interference filter according to any one of claims 1 to 6, wherein a side surface of the recess is positioned outward from an inner side surface of the support member when viewed from the first direction.

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