Fabry-perot interference filter

Abstract

This Fabry-Perot interference filter comprises a first reflective film and a second reflective film facing each other in a first direction, a first layer, and a second layer. The second layer includes a substrate, a second electrode disposed on a first surface of the substrate, a third electrode disposed on a second surface of the substrate, and a through-electrode electrically connecting the second electrode and the third electrode in the substrate. The first layer includes an electrode part, a support part joined to the second layer, and an elastic deformation part connecting the electrode part and the support part. When viewed from the first direction, the end part of the through-electrode on the second electrode side is located in a portion of the region between the electrode part and the support part that does not overlap the elastic deformation part.

Description

Fabry-Perot interference filter

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

[0002] a first electrode formed on the first surface of the first substrate; a second electrode formed on the second surface of the second substrate so as to face the first electrode; a first pad and a second pad formed on a third surface of the second substrate opposite the first substrate; a first through electrode provided on the second substrate and electrically connecting the first electrode and the first pad; and a second through electrode provided on the second substrate and electrically connecting the second electrode and the second pad, wherein a Fabry-Perot interference filter is known in which a portion of the first substrate supporting the first reflection film is configured as a movable part for changing the distance between the first reflection film and the second reflection film (see, for example, Patent Document 1).

[0003] JP 2013-83850 A

[0004] Generally, in a film-like electrode connected to a through electrode, the film thickness is likely to change at the connection point of the through electrode. Therefore, in the Fabry-Perot interference filter described above, a configuration in which the first through electrode and the second through electrode are arranged outside the elastic deformation portion of the first substrate supporting the movable portion is sometimes adopted. However, if such a configuration is adopted, the bonding area between the first substrate and the second substrate may be reduced, which may reduce the reliability of the Fabry-Perot interference filter.

[0005] An object of the present disclosure is to provide a Fabry-Perot interference filter that can ensure reliability.

[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 transmission region; a first layer including a first electrode and supporting the first reflective film; and a second layer stacked on the first layer on one side in a first direction in which the first reflective film and the second reflective film face each other, wherein the second layer includes a substrate having a first surface on the first layer side and a second surface opposite to the first layer; a second electrode disposed on the first surface and facing the first electrode across a space in the first direction; and a third electrode disposed on the second surface; and a through electrode electrically connecting the first layer to the third electrode, the first layer being a movable layer configured as a movable portion whose portion overlapping the light-transmitting region is movable in the first direction, the first layer being provided on the movable portion and including an electrode portion on which the first electrode is provided or which is the first electrode, a support portion which surrounds the movable portion when viewed from the first direction and is joined to the second layer, and an elastic deformation portion which connects the electrode portion and the support portion, the end of the through electrode on the second electrode side being located in a region between the electrode portion and the support portion which does not overlap with the elastic deformation portion when viewed from the first direction.

[0007] In the Fabry-Perot interference filter described in [1] above, a through electrode electrically connects the second electrode and the third electrode in the substrate of the second layer. When viewed from a first direction in which the first reflective film and the second reflective film face each other, the end of the through electrode facing the second electrode is located in a region between the electrode portion and the support portion that does not overlap with the elastically deformable portion. This ensures flatness in at least the region of the second electrode facing the first electrode, thereby reliably generating a desired electrostatic force between the first electrode and the second electrode. Furthermore, even if the end of the through electrode facing the second electrode is formed convex, physical interference between the end of the through electrode facing the second electrode and the elastically deformable portion can be suppressed. Furthermore, a sufficient bonding area between the support portion of the first layer and the second layer can be ensured, thereby improving the stability of the bonding between the first layer and the second layer. As a result, the Fabry-Perot interference filter described in [1] above can ensure reliability.

[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], further comprising a third layer stacked on the first layer on the other side in the first direction and supporting the second reflective film." According to the Fabry-Perot interference filter according to [2], the movable part of the first layer can be protected from both sides by the second layer and the third layer.

[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], wherein the elastic deformation portions are a plurality of elastic deformation portions connecting the electrode portion and the support portion, and the end of the through electrode is located in a region between a pair of adjacent elastic deformation portions of the plurality of elastic deformation portions when viewed from the first direction." According to the Fabry-Perot interference filter according to [3], the end of the through electrode can be arranged in a well-balanced manner with respect to the electrode portion, support portion, and plurality of elastic deformation portions of the first layer. Furthermore, since the movable portion is supported by a plurality of elastic deformation portions, the parallelism of the first reflection film with respect to the second reflection film can be more reliably ensured.

[0010] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [4] "the Fabry-Perot interference filter according to the above [3], wherein the through electrodes are a plurality of through electrodes electrically connecting the second electrode and the third electrode, and a plurality of ends of the through electrodes on the second electrode side are located in the region between the pair of elastic deformation portions when viewed from the first direction." According to the Fabry-Perot interference filter according to [4], even when a plurality of through electrodes are provided on the second layer substrate, the ends of the plurality of through electrodes can be arranged in a balanced manner with respect to the electrode portion, support portion, and plurality of elastic deformation portions of the first layer. Furthermore, since the second electrode and the third electrode are electrically connected by a plurality of through electrodes, wiring resistance can be reduced, and the potential difference between the second electrode and the third electrode can be reduced.

[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], wherein the through electrode is located in a region between the electrode portion and the support portion that does not overlap with the elastic deformation portion when viewed from the first direction." According to the Fabry-Perot interference filter described in [5], the configuration of the through electrode can be simplified, for example, by forming the through electrode linearly along the first direction in which the first reflective film and the second reflective film face each other.

[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 [1] to [5] above, in which the elastically deforming portion is electrically conductive." If, when viewed from the first direction, the end of the through electrode on the second electrode side overlaps with the electrically conductive elastically deforming portion, variations in the shape of the end may cause variations in the magnitude of the electrostatic force generated between the end and the elastically deforming portion, and the parallelism of the first reflection film relative to the second reflection film may not be ensured. According to the Fabry-Perot interference filter described in [6], when viewed from the first direction, the end of the through electrode on the second electrode side does not overlap with the electrically conductive elastically deforming portion, so that the parallelism of the first reflection film relative to the second reflection film can be ensured even if the shape of the end of the through electrode on the second electrode side varies.

[0013] According to the present disclosure, it is possible to provide a Fabry-Perot interference filter that can ensure reliability.

[0014] 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 plan view and a cross-sectional view of the Fabry-Perot interference filter shown in FIG. 1. FIG. 10 is a longitudinal cross-sectional view of a modified Fabry-Perot interference filter. FIG. 11 is a plan view of a portion of a modified Fabry-Perot interference filter. FIG. 12 is a plan view of a portion of a modified Fabry-Perot interference filter. FIG. 13 is a cross-sectional view of a portion of the Fabry-Perot interference filter taken along line XIII-XIII shown in FIG. 12. FIG. 14 is a longitudinal sectional view of a portion of an absorbing film of a modified Fabry-Perot interference filter.

[0015] 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.

[0016] As shown in Figures 1, 2, 3, and 4, the Fabry-Perot interference filter 1 includes a first layer 10, a second layer 20, a third 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, when simply referring to "one side," it means one side in the Z-axis direction, and when simply referring to "the other side," it means the other side in the Z-axis direction. Furthermore, when simply referring to "thickness," it means the thickness in the Z-axis direction.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] The support member 15 surrounds the light transmitting member 14 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.

[0022] 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, a semiconductor material such as p-type silicon with low resistance (1 Ωcm or less). 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.

[0023] 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. 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 straight 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. In other words, the first layer 10 includes the first electrode 19.

[0024] The support portion 17 surrounds the electrode portion 16 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. 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, approximately 0.5 to 1.5 mm.

[0025] 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.

[0026] 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 on the inner edge region of the support portion 17 are lower than the surface 17a on one side of the support portion 17. The surface 16b on the other side of the electrode portion 16, the surface 18b on the other side of each elastically deforming portion 18, and the surface 17b on 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.

[0027] 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.

[0028] 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.

[0029] The first reflective film 50 is disposed on the surface 14b on the other side of the light-transmitting member 14. In other words, the first layer 10 supports the first reflective film 50. The first reflective film 50 is movable in the Z-axis direction together with the movable part 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 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 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 configured 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 configured by laminating a plurality of such dielectric films.

[0030] 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.

[0031] 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 (second surface) opposite the first layer 10, and the surface 21b is the surface (first 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 made of a light-transmitting material such as glass or silicon. 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. Note that 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.

[0032] 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.

[0033] The second electrodes 22 are disposed on the surface 21b of the second substrate 21. When viewed from the Z-axis direction, the second electrodes 22 surround the light-transmitting region 1a 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 in the circumferential direction at equal angular intervals, and a slit-like gap extending in the radial direction is formed between each 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 the second electrodes 22 are arranged along the circumference. For example, when four second electrodes 22 are arranged along a circumference with a diameter of 5 mm, the width is approximately 4 mm. The thickness of each second electrode 22 is, for example, about 1 to 5 μm. The width of the gap between a pair of adjacent second electrodes 22 is, for example, about 0.1 mm. In the initial state (i.e., a state in which no electrostatic force is acting between the first electrode 19 and each second electrode 22), the distance between the electrode portion 16 (i.e., the first electrode 19) and each second electrode 22 is, for example, about 3 μm.

[0034] 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 ).

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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 made of a light-transmitting material such as glass or silicon. 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, about 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.

[0043] 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 the outer edge 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 is, for example, about 0.1 mm. The height of each protrusion in the Z-axis direction is, for example, about 50 nm.

[0044] 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 outer edge 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, in the initial state, the portions of the second reflective film 60 located on the convex portions 32 are in contact with the outer edge region of the first reflective film 50. This creates a space between the first reflective film 50 and the second reflective film 60 in the light-transmitting region 1a, preventing contact between the first reflective film 50 and the second reflective film 60. The second reflective film 60 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 second reflective film 60 is, for example, approximately 5 to 8 mm. The thickness of the second reflective film 60 is, for example, about 210 nm. The distance between the first reflective film 50 and the second reflective film 60 in the initial state 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.

[0045] 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.

[0046] 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.

[0047] As shown in FIG. 9 , the first layer 10 and the second layer 20 have a first region R1, a second region R2, and a third region R3. The first region R1 is a region that includes the movable portion 10a when viewed from the Z-axis direction. In the Fabry-Perot interference filter 1, the first region R1 is a region that is located inside the inner edge of the surface 17a of the support portion 17 when viewed from the Z-axis direction. The second region R2 is a region that surrounds the first region R1 when viewed from the Z-axis direction. In the Fabry-Perot interference filter 1, the second region R2 is a region that overlaps with the surface 17a of the support portion 17 excluding the region corresponding to the cutout portion 210 when viewed from the Z-axis direction. The third region R3 is a region that is located outside the second region R2 and on one side in the X-axis direction when viewed from the Z-axis direction. In the Fabry-Perot interference filter 1, the third region R3 is a region that overlaps with the cutout portion 210 when viewed from the Z-axis direction. That is, the cutout portion 210 is a cutout portion formed by cutting out the outer edge of the second substrate 21 so as to overlap with the third region R3 when viewed from the Z-axis direction. Note that (a) in Fig. 9 is a plan view of the Fabry-Perot interference filter 1, and (b) in Fig. 9 is a cross-sectional view of the Fabry-Perot interference filter 1 between the first layer 10 and the second layer 20. In (b) in Fig. 9, the boundary between the first region R1 and the second region R2 and the boundary between the second region R2 and the third region R3 are indicated by dashed lines.

[0048] The electrode portion 16 and each elastic deformation portion 18 are separated from the second layer 20 in the first region R1. Specifically, the surface 16a of the electrode portion 16 and the surface 18a of each elastic deformation portion 18 are separated from the surface 21b of the second substrate 21 and each second electrode 22 in the first region R1 (see FIG. 4 ). In other words, the first region R1 is a region where the electrode portion 16 and each elastic deformation portion 18 are separated from the second layer 20. The support portion 17 is bonded to the second layer 20 in the second region R2. Specifically, the surface 17a of the support portion 17 is bonded to the surface 21b of the second substrate 21 in the second region R2 (see FIG. 4 ). In other words, the second region R2 is a region where the support portion 17 is bonded to the second layer 20. The support portion 17 is exposed to space in the third region R3. Specifically, the surface 17a of the support portion 17 is exposed to the space in the third region R3. That is, the third region R3 is a region where the support portion 17 is exposed to the space. The metal pad 13 is formed on the support portion 17 in the third region R3. Specifically, the metal pad 13 is formed on the surface 17a of the support portion 17 in the third region R3.

[0049] The width W1 of the metal pad 13 in the Y-axis direction is larger than the distance D between the first region R1 and the third region R3 in the X-axis direction. The width W2 of the third region R3 in the X-axis direction is smaller than the width W3 of the third region R3 in the Y-axis direction. The width W1 of the metal pad 13 in the Y-axis direction is larger than the width W4 of the opening 23a of the light-shielding film 23 (the light-shielding film arranged on one side in the Z-axis direction relative to the first layer 10 and the second layer 20) in the Y-axis direction. In the Y-axis direction, both ends 13a of the metal pad 13 are located outside the opening 23a of the light-shielding film 23. The width W1 is the maximum width of the metal pad 13 in the Y-axis direction. The width W2 is the maximum width of the third region R3 in the X-axis direction. The width W3 is the maximum width of the third region R3 in the Y-axis direction. The width W4 is the maximum width of the opening 23a of the light-shielding film 23 in the Y-axis direction. The distance D is the minimum distance between the first region R1 and the third region R3 in the X-axis direction. In the Fabry-Perot interference filter 1, the width W1 of the metal pad 13 in the Y-axis direction is larger than the width (maximum width of the opening 70c in the Y-axis direction) of the opening 70c in the absorbing film 70 (a light-shielding film arranged on the other side in the Z-axis direction with respect to the first layer 10 and the second layer 20).

[0050] The first region R1 includes a plurality of regions R4. When viewed from the Z-axis direction, each region R4 is a region between the electrode portion 16 and the support portion 17 that does not overlap with a plurality of elastic deformation portions 18, and is a region between a pair of adjacent elastic deformation portions 18 when viewed from the Z-axis direction. The plurality of through electrodes 26 are located in the plurality of regions R4 when viewed from the Z-axis direction. In the Fabry-Perot interference filter 1, two through electrodes 26 are located in each region R4 when viewed from the Z-axis direction. Note that in (b) of FIG. 9, each region R4 is indicated by dot hatching.

[0051] 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 hermetically bonded to each other, and the multiple through holes formed in the second substrate 21 are hermetically blocked by multiple through electrodes 26, so that the movable part 10a moves in the Z-axis direction in the airtight space.

[0052] As described above, in the Fabry-Perot interference filter 1, the plurality of through electrodes 26 electrically connect the plurality of second electrodes 22 and the plurality of third electrodes 24 in the second substrate 21 of the second layer 20. When viewed from the Z-axis direction, the plurality of through electrodes 26 are located in region R4 between the electrode portion 16 and the support portion 17, where the through electrodes 26 do not overlap with the plurality of elastic deformation portions 18. This ensures flatness of at least the region of each second electrode 22 facing the first electrode 19, thereby reliably generating a desired electrostatic force between the first electrode 19 and each second electrode 22. Furthermore, even if the end of each through electrode 26 facing the second electrode 22 is formed convex, physical interference between the end of each through electrode 26 facing the second electrode 22 and each elastic deformation portion 18 can be suppressed. Furthermore, a sufficient bonding area can be ensured between the support portion 17 of the first layer 10 and the second substrate 21 of the second layer 20, thereby improving the stability of the bonding between the first layer 10 and the second layer 20. As described above, the Fabry-Perot interference filter 1 can ensure reliability.

[0053] The through electrodes 26 are generally formed by embedding a metal material in through holes formed in the second substrate 21, plating the inner surfaces of the through holes formed in the second substrate 21 with a metal, or the like, and unevenness is likely to be formed in the second electrode 22 and the third electrode 24 at the locations where both ends of the through electrodes 26 are connected. Therefore, when viewed from the Z-axis direction, it is extremely important to position the through electrodes 26 in region R4 between the electrode portion 16 and the support portion 17, which does not overlap with the multiple elastic deformation portions 18, in order to ensure a sufficient bonding area between the support portion 17 of the first layer 10 and the second substrate 21 of the second layer 20, and to reliably generate a desired electrostatic force between the first electrode 19 and each second electrode 22.

[0054] 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.

[0055] In the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, at least two of the plurality of through electrodes 26 are located in each region R4 between a pair of adjacent elastic deformation portions 18 among the plurality of elastic deformation portions 18. This allows the ends of the plurality of through electrodes 26 to be arranged in a well-balanced manner with respect to the electrode portion 16, support portion 17, and plurality of elastic deformation portions 18 of the first layer 10, even when the plurality of through electrodes 26 are provided on the second substrate 21 of the second layer 20. Furthermore, because the movable portion 10a is supported by the plurality of elastic deformation portions 18, the parallelism of the first reflection film 50 with respect to the second reflection film 60 can be more reliably ensured. Furthermore, because one second electrode 22 and one third electrode 24 are electrically connected by the plurality of through electrodes 26, the wiring resistance can be reduced, and the potential difference between one second electrode 22 and one third electrode 24 can be reduced.

[0056] In the Fabry-Perot interference filter 1, the multiple elastic deformation portions 18 are conductive. When viewed from the Z-axis direction, if the end portion of at least one through electrode 26 on the second electrode 22 side overlaps with at least one elastic deformation portion 18 that is conductive, variations in the shape of the end portion will cause variations in the magnitude of the electrostatic force generated between the end portion and the elastic deformation portion 18, and there is a risk that the parallelism of the first reflection film 50 with respect to the second reflection film 60 will not be ensured. According to the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, the end portion of each through electrode 26 on the second electrode 22 side does not overlap with each elastic deformation portion 18 that is conductive, so that the parallelism of the first reflection film 50 with respect to the second reflection film 60 can be ensured even if the shape of the end portion of each through electrode 26 on the second electrode 22 side varies.

[0057] In the Fabry-Perot interference filter 1, the first electrode 19 and the metal pad 13 are electrically connected via the semiconductor layer 12 of the first layer 10. This eliminates the need to form a wiring layer between the first layer 10 and the second layer 20 to electrically connect the first electrode 19 and the metal pad 13, thereby improving the stability of the bond between the first layer 10 and the second layer 20. Furthermore, the width W1 of the metal pad 13 in the Y-axis direction is greater than the distance D between the first region R1 and the third region R3 in the X-axis direction, and the width W2 of the third region R3 in the X-axis direction is smaller than the width W3 of the third region R3 in the Y-axis direction. This increases the contact area between the metal pad 13 and the support portion 17 of the semiconductor layer 12, thereby increasing the probability of ohmic contact being formed between the metal pad 13 and the support portion 17 of the semiconductor layer 12. Furthermore, since the distance between the metal pad 13 and the first electrode 19 can be reduced, it is possible to suppress the occurrence of a potential difference within the first electrode 19, and as a result, it is possible to suppress the distance between the first reflective film 50 and the second reflective film 60 from varying depending on the location. As a result, the Fabry-Perot interference filter 1 can ensure reliability.

[0058] In the Fabry-Perot interference filter 1, the second substrate 21 has a notch 210 formed by cutting out the outer edge of the second substrate 21 so as to overlap with the third region R3 when viewed from the Z-axis direction. This allows external wiring such as wires to be easily and reliably connected to the metal pad 13.

[0059] The present disclosure is not limited to the above embodiment. For example, 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.

[0060] 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.

[0061] 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 this example, 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.

[0062] 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.

[0063] 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.

[0064] 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. With this configuration, when light enters the Fabry-Perot interference filter 1 from the surface 21 a of the second substrate 21 of the second layer 20, it is possible to more reliably prevent the light from traveling into the Fabry-Perot interference filter 1 from areas of the surface 21 a that do not face the first reflective film 50 and the second reflective film 60, and as a result, it is possible to more reliably prevent stray light from being emitted from the Fabry-Perot interference filter 1 due to multiple reflections or the like within the Fabry-Perot interference filter 1.

[0065] In the Fabry-Perot interference filter 1, at least the end of the through electrode 26 on the second electrode 22 side needs to be located in region R4 between the electrode portion 16 and the support portion 17 when viewed from the Z-axis direction, which does not overlap with the elastic deformation portion 18.

[0066] In the Fabry-Perot interference filter 1, the width W1 of the metal pad 13 in the Y-axis direction may be larger than the width of at least one of the first reflective film 50 and the second reflective film 60 in the Y-axis direction (the maximum width of at least one of the first reflective film 50 and the second reflective film 60 in the Y-axis direction). In this case, too, the probability of forming an ohmic contact between the metal pad 13 and the support portion 17 of the semiconductor layer 12 can be further increased. Furthermore, in the Fabry-Perot interference filter 1, both ends 13a of the metal pad 13 may be located outside at least one of the first reflective film 50 and the second reflective film 60 in the Y-axis direction. In this case, too, the generation of a potential difference within the first electrode 19 can be more reliably suppressed, and as a result, the distance between the first reflective film 50 and the second reflective film 60 can be more reliably suppressed from varying depending on the location.

[0067] The metal pad 13 may be a plurality of metal pads 13 electrically connected to the first electrode 19 via the semiconductor layer 12. As an example, as shown in FIG. 11 , a plurality of metal pads 13 may be arranged on a region of the surface 17a of the support portion 17 of the semiconductor layer 12 that is exposed to the outside in the cutout portion 210 of the second substrate 21. In this example, each metal pad 13 is formed in a rectangular shape when viewed from the Z-axis direction, and the plurality of metal pads 13 are aligned in the Y-axis direction. In this way, when a plurality of metal pads 13 are formed on the support portion 17 in the third region R3 (see FIG. 9B ), the width W1 of the metal pad 13 in the Y-axis direction means the sum of the widths of the metal pads 13 in the Y-axis direction.

[0068] The metal pad 13 may be formed in a region of the support portion 17 of the semiconductor layer 12 that is exposed to the space. As an example, as shown in FIGS. 12 and 13 , the metal pad 13 may be disposed on a surface 17d of a step portion 170 formed in the support portion 17. In this example, the step portion 170 is formed in the support portion 17 along a portion of the outer edge of the support portion 17. The surface 17d of the step portion 170 is lower than the surface 17a of the support portion 17 and is spaced apart from the second layer 20. In other words, when viewed from the Z-axis direction, the surface 17d of the step portion 170 corresponds to the third region R3 (see (b) of FIG. 9 ). In this example, the width of the notch 210 in the Y-axis direction is smaller than the widths of the step portion 170 and the metal pad 13 in the Y-axis direction. Even in this case, external wiring such as a wire can be easily and reliably connected to the metal pad 13 via the notch 210.

[0069] The absorbing film 70 may have light absorption properties not only on one surface 70a but also on the other surface 70b. An example of an absorbing film 70 having light absorption properties on both surfaces 70a and 70b will be described. As shown in FIG. 14 , the absorbing film 70 has a multilayer structure including a reflective layer 71, a pair of resonant layers 72, and a pair of absorbing layers 73. The pair of resonant layers 72 are arranged on both sides of the reflective layer 71 in the Z-axis direction, and the pair of absorbing layers 73 are arranged on both sides of the pair of resonant layers 72 in the Z-axis direction. The reflective layer 71 is a metal layer that does not transmit light incident on the surface 70a on one side or the surface 70b on the other side. At the wavelength of light incident on the surface 70a on one side, the optical transmittance inside the resonant layer 72 on one side is greater than the optical transmittance inside the absorbing layer 73 on one side. At the wavelength of light incident on the surface 70a on one side, the optical reflectance of the surface of the reflective layer 71 on one side is greater than the optical reflectance of the surface of the resonant layer 72 on one side. At the wavelength of light incident on the other surface 70a, the optical transmittance inside the other resonant layer 72 is greater than the optical transmittance inside the other absorbing layer 73. At the wavelength of light incident on the other surface 70a, the optical reflectance of the surface of the other reflective layer 71 is greater than the optical reflectance of the surface of the other resonant layer 72. In the absorbing film 70 configured in this manner, both surfaces 70a, 70b have optical absorption properties.

[0070] In the Fabry-Perot interference filter 1, 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. Note that even when the third layer 30 is stacked on the first layer 10, the second layer 20, rather than the third layer 30, may support the second reflective film 60.

[0071] 1...Fabry-Perot interference filter, 1a...light transmission region, 10...first layer (movable layer), 10a...movable portion, 16...electrode portion, 17...support portion, 18...elastic deformation portion, 19...first electrode, 20...second layer, 21...second substrate (substrate), 21a...surface (second surface), 21b...surface (first surface), 22...second electrode, 24...third electrode, 26...through electrode, 30...third layer, 50...first reflective film, 60...second reflective film, R4...region.

Claims

a first reflective film; a second reflective film facing the first reflective film across a space in a light transmitting region; a first layer including a first electrode and supporting the first reflective film; and a second layer stacked on the first layer on one side in a first direction in which the first reflective film and the second reflective film face each other, the second layer including: a substrate having a first surface on the first layer side and a second surface opposite to the first layer; a second electrode disposed on the first surface and facing the first electrode across a space in the first direction; a third electrode disposed on the second surface; and a through electrode provided on the substrate and electrically connecting the second electrode and the third electrode; the first layer is a movable layer having a portion overlapping the light transmitting region configured as a movable portion movable in the first direction, the first layer including: an electrode portion provided on the movable portion and having the first electrode or being the first electrode; A Fabry-Perot interference filter comprising: a support portion that surrounds the movable portion when viewed from the first direction and is joined to the second layer; and an elastic deformation portion that connects the electrode portion and the support portion, wherein an end portion of the through electrode on the second electrode side is located in a region between the electrode portion and the support portion that does not overlap with the elastic deformation portion when viewed from the first direction.

2. A Fabry-Perot interference filter as claimed in claim 1, further comprising a third layer laminated on said first layer on the other side in said first direction and supporting said second reflecting film.

3. A Fabry-Perot interference filter as described in claim 1 or 2, wherein the elastic deformation portion is a plurality of elastic deformation portions connecting the electrode portion and the support portion, and the end portion of the through electrode is located in a region between a pair of adjacent elastic deformation portions among the plurality of elastic deformation portions when viewed from the first direction.

4. A Fabry-Perot interference filter as described in claim 3, wherein the through electrodes are a plurality of through electrodes electrically connecting the second electrode and the third electrode, and a plurality of ends of the plurality of through electrodes on the second electrode side are located in the region between the pair of elastic deformation portions when viewed from the first direction.

5. A Fabry-Perot interference filter described in any one of claims 1 to 4, wherein the through electrode is located in the region between the electrode portion and the support portion that does not overlap with the elastic deformation portion when viewed from the first direction.

6. The Fabry-Perot interference filter according to any one of claims 1 to 5, wherein the elastically deformable portion has electrical conductivity.

Images