Fabry-perot interference filter and method for manufacturing fabry-perot interference filter

Abstract

This Fabry-Perot interference filter includes a first reflection film, a second reflection film, and a movable layer. The movable layer includes a movable member, a support member, and a connection layer. The connection layer includes: a movable part joined to the movable member; a support part joined to the support member; and an elastic deformation part connecting the movable part and the support part. The movable part: is connected to a first boundary section of the elastic deformation part; and includes a first connection section that is joined to the movable member. The support part: is connected to a second boundary section of the elastic deformation part; and includes a second connection section joined to the support member. The elastic deformation part, the first connection section, and the second connection section are configured to serve as elastic deformation planned sections in the connection layer.

Description

Fabry-Perot interference filter and method for manufacturing the same

[0001] The present disclosure relates to Fabry-Perot interference filters and methods for manufacturing Fabry-Perot interference filters.

[0002] A Fabry-Perot interference filter is known that includes a first reflective film and a second reflective film facing each other, a movable member on which the first reflective film is formed, a frame-shaped support member inside which the movable member is arranged, and a connection layer bonded to each of the movable member and the support member, wherein the connection layer includes a movable portion bonded to the movable member, a support portion bonded to the support member, and an elastic deformation portion connecting the movable portion and the support portion (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2023-21702

[0004] In a Fabry-Perot interference filter such as that described above, if the joining position of at least one of the movable member and the support member relative to the connecting layer is shifted, for example due to a manufacturing error, the shape of the area of ​​the elastic deformation portion where elastic deformation is actually permitted will change, and it may not be possible to move the first reflection film relative to the second reflection film with high precision.

[0005] The present disclosure aims to provide a Fabry-Perot interference filter that can move a first reflective film with high precision relative to a second reflective film, and a method for manufacturing a Fabry-Perot interference filter that can obtain such a Fabry-Perot interference filter.

[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; and a movable layer supporting the first reflective film in a movable portion movable in a direction in which the first reflective film and the second reflective film face each other, the movable layer including a movable member that is a part of the movable portion, a support member, and a connection layer bonded to each of the movable member and the support member, the connection layer being a part of the movable portion and including a movable portion bonded to the movable member, and the support member." a support portion joined to the movable portion, and an elastic deformation portion connecting the movable portion and the support portion, wherein the movable portion includes a first connection portion connected to a first boundary portion which is an end portion of the elastic deformation portion on the movable portion side and joined to the movable member, and the support portion includes a second connection portion connected to a second boundary portion which is an end portion of the elastic deformation portion on the support portion side and joined to the support member, and the elastic deformation portion, the first connection portion, and the second connection portion are configured as elastically deformable portions in the connection layer.

[0007] In the above-mentioned Fabry-Perot interference filter, in a configuration in which the movable part is joined to the movable member and the support part is joined to the support member with the movable part and the support part connected by an elastic deformation part, the elastic deformation part, the first connection part of the movable part, and the second connection part of the support part are configured as elastically deformable parts in the connection layer. As a result, even if the joining position of at least one of the movable member and the support member relative to the connection layer is shifted due to, for example, a manufacturing error, the region of the elastically deformable part that is actually allowed to elastically deform is likely to be maintained in a predetermined shape as the elastic deformation part. Therefore, with the above-mentioned Fabry-Perot interference filter, it is possible to move the first reflection film with respect to the second reflection film with high precision.

[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, when viewed from the direction, the first connection portion has substantially the same width as the first boundary portion, and when viewed from the direction, the second connection portion has substantially the same width as the second boundary portion." With this Fabry-Perot interference filter, it is possible to easily realize a configuration in which a region of the intended elastic deformation portion that is actually allowed to elastically deform can be maintained in a predetermined shape as an elastic deformation portion.

[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 elastic deformation portion is each of a plurality of elastic deformation portions." With this Fabry-Perot interference filter, it is possible to move the first reflective film with respect to the second reflective film with higher precision.

[0010] The Fabry-Perot interference filter according to one aspect of the present disclosure may be the Fabry-Perot interference filter according to [3] above, wherein [4] "the movable portion is an electrode for generating an electrostatic force or a portion on which an electrode for generating an electrostatic force is provided, the movable member has a first bonding surface including a bonding region with the movable portion, an outer edge of the movable portion when viewed from the direction includes a first portion extending from the first connection portion to an opposite side of the first connection portion with respect to each of the plurality of elastic deformation portions, and a second portion extending from the first portion to an opposite side of the first connection portion with respect to each of the plurality of elastic deformation portions, the first portion and the second portion being located inside the outer edge of the first bonding surface when viewed from the direction, and a distance between the outer edge of the first bonding surface and the first portion is greater than a distance between the outer edge of the first bonding surface and the second portion when viewed from the direction." This Fabry-Perot interference filter allows for an increase in the area of ​​the electrode for generating an electrostatic force or the movable portion on which the electrode for generating an electrostatic force is provided.

[0011] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [5] "the Fabry-Perot interference filter according to the above [4], in which the distance between the outer edge of the first bonding surface and the second portion is equal to or less than half the distance between the outer edge of the first bonding surface and the first portion." With this Fabry-Perot interference filter, it is possible to reliably increase the area of ​​the electrode for generating electrostatic force or the movable portion where the electrode for generating electrostatic force is provided.

[0012] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [6] "the Fabry-Perot interference filter according to the above [4] or [5], in which the length of the second portion is greater than the length of the first portion." With this Fabry-Perot interference filter, it is possible to reliably increase the area of ​​the electrode for generating electrostatic force or the movable portion where the electrode for generating electrostatic force is provided.

[0013]

[0013] A Fabry-Perot interference filter according to one aspect of the present disclosure may be the Fabry-Perot interference filter according to any one of claims 4 to 6, wherein the support member has a second bonding surface including a bonding region with the support portion, and an outer edge of the support portion when viewed from the direction includes a third portion extending from the second connection portion to an opposite side of the second connection portion with respect to each of the plurality of elastic deformation portions, and a fourth portion extending from the third portion to an opposite side of the second connection portion with respect to each of the plurality of elastic deformation portions, the third portion and the fourth portion being located inside the outer edge of the second bonding surface when viewed from the direction, and the distance between the outer edge of the second bonding surface and the third portion is greater than the distance between the outer edge of the second bonding surface and the fourth portion when viewed from the direction. In this Fabry-Perot interference filter, by making the shape of each elastically deformable portion symmetrical on the first connection portion side and the second connection portion side, it is possible to obtain appropriate characteristics for each elastic deformation portion.

[0014] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [8] "the Fabry-Perot interference filter according to the above [7], in which the distance between the outer edge of the second bonding surface and the fourth portion is equal to or less than half the distance between the outer edge of the second bonding surface and the third portion." According to this Fabry-Perot interference filter, by making the shape of each elastically deforming portion symmetrical on the first connecting portion side and the second connecting portion side, appropriate characteristics can be obtained for each elastically deforming portion.

[0015] A Fabry-Perot interference filter according to one aspect of the present disclosure may be [9] "the Fabry-Perot interference filter according to the above [7] or [8], in which the length of the fourth portion is greater than the length of the third portion." According to this Fabry-Perot interference filter, by making the shape of each elastically deforming portion symmetrical on the first connection portion side and the second connection portion side, it is possible to obtain appropriate characteristics for each elastically deforming portion.

[0016] A Fabry-Perot interference filter according to one aspect of the present disclosure may be

[10] "the Fabry-Perot interference filter according to any one of the above [3] to [9], in which a pair of corners formed on both sides of the first connection portion for each of the plurality of elastic deformation portions have a continuous curvature." With this Fabry-Perot interference filter, it is possible to suppress stress concentration on the first connection portion due to, for example, a difference in thermal expansion coefficient between the movable member and the connection layer.

[0017] A Fabry-Perot interference filter according to one aspect of the present disclosure may be

[11] "the Fabry-Perot interference filter according to any one of the above [3] to

[10] , in which a pair of corners formed on both sides of the second connection portion for each of the plurality of elastic deformation portions have a continuous curvature." With this Fabry-Perot interference filter, it is possible to suppress stress concentration on the second connection portion due to, for example, a difference in thermal expansion coefficient between the support member and the connection layer.

[0018] A Fabry-Perot interference filter according to one aspect of the present disclosure may be

[12] "the Fabry-Perot interference filter according to any one of [1] to

[11] above, wherein the thickness of the movable member in the direction is greater than the thickness of the connection layer in the direction." According to this Fabry-Perot interference filter, the movable member can stably support the first reflective film. Furthermore, as the thickness of the movable member increases, there is a risk that the characteristics of the elastically deforming portion will change significantly depending on the bonding state between the movable member and the connection layer. However, as described above, the region of the elastically deforming portion that is actually allowed to elastically deform is more likely to be maintained in a predetermined shape as the elastically deforming portion, and therefore the characteristics of the elastically deforming portion can be appropriately maintained.

[0019] A manufacturing method for a Fabry-Perot interference filter according to one aspect of the present disclosure is

[13] "a manufacturing method for a Fabry-Perot interference filter according to any one of the above [1] to

[12] , comprising: a first step of preparing a first base material layer including a portion that will become the movable member and the support member, and a second base material layer including a portion that will become the connection layer, and bonding a main surface of the first base material layer to a main surface of the second base material layer; and a second step of, after the first step, etching the first base material layer to form the movable member and the support member, and etching the second base material layer to form the connection layer."

[0020] The above-mentioned manufacturing method for a Fabry-Perot interference filter makes it possible to easily form a configuration in which the movable part is joined to the movable member and the support part is joined to the support member with the movable part and the support part connected by the elastic deformation part. In this case, even if the joining position of at least one of the movable member and the support part relative to the connecting layer is shifted due to, for example, a manufacturing error, the region of the elastic deformation part that is actually allowed to elastically deform is likely to be maintained in a predetermined shape as the elastic deformation part. Therefore, the above-mentioned manufacturing method for a Fabry-Perot interference filter makes it possible to obtain a Fabry-Perot interference filter in which the first reflection film can be moved with high precision relative to the second reflection film.

[0021] According to the present disclosure, it is possible to provide a Fabry-Perot interference filter that can move a first reflective film with high precision relative to a second reflective film, and a manufacturing method for a Fabry-Perot interference filter that can obtain such a Fabry-Perot interference filter.

[0022] 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 of a portion of the first layer shown in FIG. 5. FIG. 10 is a plan view of a portion of the first layer shown in FIG. 5. FIG. 11 is a longitudinal cross-sectional view showing a manufacturing process of the Fabry-Perot interference filter shown in FIG. 1. FIG. 12 is a longitudinal cross-sectional view showing a manufacturing process of the Fabry-Perot interference filter shown in FIG. 1. FIG. 13 is a longitudinal cross-sectional view showing a manufacturing process of the Fabry-Perot interference filter shown in FIG. 1. Fig. 14 is a longitudinal sectional view showing a manufacturing process of the Fabry-Perot interference filter shown in Fig. 1. Fig. 15 is a longitudinal sectional view of a modified Fabry-Perot interference filter. Fig. 16 is a longitudinal sectional view of a modified Fabry-Perot interference filter. Fig. 17 is a longitudinal sectional view of a modified Fabry-Perot interference filter.

[0023] 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]

[0024] 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 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.

[0025] 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." In the following description, the side closer to the straight line L is referred to as the inner side, and the side farther from the straight line L is referred to as the outer side. 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.

[0026] 4 and 5, the first layer 10 includes a first substrate 11, a semiconductor layer (connection 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.

[0027] The first substrate 11 includes a light-transmitting member (movable 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.

[0028] 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.

[0029] 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.

[0030] The semiconductor layer 12 is bonded to each of the light transmitting member 14 and the support member 15. The semiconductor layer 12 includes an electrode portion (movable 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.

[0031] The electrode portion 16 surrounds the light-transmitting region 1a when viewed from the Z-axis direction. The electrode portion 16 extends along the outer edge of the light-transmitting member 14 when viewed from the Z-axis direction and is bonded to the surface 14a on one side of the light-transmitting member 14. In other words, the electrode portion 16 is bonded to the light-transmitting member 14. When viewed from the Z-axis direction, the outer edge of the electrode portion 16 is located inside the outer edge of the light-transmitting member 14. When viewed from the Z-axis direction, the inner edge of the electrode portion 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 portion 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 portion 16 is, for example, approximately 3 to 5 mm. The outer diameter of the electrode portion 16 is, for example, approximately 4 to 6 mm. The thickness of the electrode portion 16 is, for example, approximately 30 μm. In the Fabry-Perot interference filter 1, the electrode portion 16 is a first electrode (electrode) 19 for generating an electrostatic force. That is, the first layer 10 includes the first electrode 19. The electrode portion 16 only needs to include a region joined to the light transmitting member 14.

[0032] 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 other words, the support portion 17 is bonded to 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 outside 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. The support portion 17 only needs to include a region joined to the support member 15 .

[0033] 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 a pair of adjacent elastic deformation portions 18 in the circumferential direction. 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.

[0034] 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.

[0035] 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.

[0036] 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. In other words, the light transmitting member 14 and the electrode portion 16 are each part of the movable portion 10a. 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.

[0037] 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 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 may be formed 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.

[0038] 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 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.

[0039] 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 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.

[0040] 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.

[0041] 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.

[0042] 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 portion 22a and a pair of protrusions 22b. The main body portion 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 portion 22a and are located on both sides of the elastic deformation portion 18 in the circumferential direction when viewed in the Z-axis direction (see FIG. 5 ). The main body portion 22a has a notch 22c that opens outward between the pair of protrusions 22b. The notch 22c overlaps one end of the elastic deformation portion 18 when viewed in the Z-axis direction (see FIG. 5 ).

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] The second reflective film 60 is disposed on the surface 31a of the third substrate 31. That is, the third layer 30 supports the second reflective film 60. The second reflective film 60 faces the first reflective film 50 across a space in the light-transmitting region 1a. 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 film 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 forms 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 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. 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 made up of only a metal film made of Ag or the like, or may be made up of only a dielectric film made of silicon oxide, titanium oxide, aluminum oxide or the like, or may be made up of a plurality of such dielectric films stacked together.

[0053] 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.

[0054] 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.

[0055] 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 causes the movable part 10a to move 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 one another, and the plurality of through holes formed in the second substrate 21 are hermetically 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 layer]

[0056] As shown in FIG. 9 , each elastic deformation portion 18 has a first boundary portion 181 and a second boundary portion 182. The first boundary portion 181 is an end portion of each elastic deformation portion 18 on the electrode portion 16 side. The second boundary portion 182 is an end portion of each elastic deformation portion 18 on the support portion 17 side. The first boundary portion 181 of each elastic deformation portion 18 is spaced apart from the light transmitting member 14. The first boundary portion 181 of each elastic deformation portion 18 is not bonded to the light transmitting member 14 and is floating in space. In the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, the first boundary portion 181 of each elastic deformation portion 18 does not overlap with the light transmitting member 14. The second boundary portion 182 of each elastic deformation portion 18 is spaced apart from the support member 15. The second boundary portion 182 of each elastic deformation portion 18 is not bonded to the support member 15 and is floating in space. In the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, the second boundary portion 182 of each elastic deformation portion 18 does not overlap with the support member 15.

[0057] The electrode portion 16 includes a plurality of first connection portions 163. Each first connection portion 163 is connected to a first boundary portion 181 of each elastic deformation portion 18 and is joined to the light transmitting member 14. The support portion 17 includes a plurality of second connection portions 173. Each second connection portion 173 is connected to a second boundary portion 182 of each elastic deformation portion 18 and is joined to the support member 15.

[0058] One elastic deformation portion 18, and one first connection portion 163 and one second connection portion 173 connected by that one elastic deformation portion 18, are configured as one elastic deformation portion 180 in the semiconductor layer 12. That is, the semiconductor layer 12 includes a plurality of elastic deformation portions 180 corresponding to the plurality of elastic deformation portions 18. Each elastic deformation portion 180 is a portion designed to elastically deform when the electrode portion 16 moves in the Z-axis direction relative to the support portion 17 when the semiconductor layer 12 exists alone.

[0059] In the Fabry-Perot interference filter 1, the width of the elastically deforming portion 18 (the width in a direction perpendicular to the direction in which the first boundary portion 181 and the second boundary portion 182 are aligned when viewed from the Z-axis direction) and the thickness of the elastically deforming portion 18 (the thickness in the Z-axis direction) are each substantially constant. In the Fabry-Perot interference filter 1, the cross-sectional shape of the elastically deforming portion 18 (the cross-sectional shape perpendicular to the extension direction of the elastically deforming portion 18) is substantially constant. Note that "substantially constant" means that the width falls within the range of a manufacturing error with respect to the design value (reference value). As an example, when the design value of the width of the elastically deforming portion 18 is a value between 50 and 500 μm, the manufacturing error is ±5 μm, and when the design value of the thickness of the elastically deforming portion 18 is a value between 20 and 50 μm, the manufacturing error is ±1 μm.

[0060] In the Fabry-Perot interference filter 1, the first connection portion 163 has substantially the same cross-sectional shape (cross-sectional shape perpendicular to the extension direction of the elastic deformation portion 18) as the first boundary portion 181 of the elastic deformation portion 18. That is, the first connection portion 163 has substantially the same width (width in a direction perpendicular to the direction in which the first boundary portion 181 and the second boundary portion 182 are aligned when viewed from the Z-axis direction) and thickness (thickness in the Z-axis direction) as the first boundary portion 181 of the elastic deformation portion 18. The second connection portion 173 has substantially the same cross-sectional shape (cross-sectional shape perpendicular to the extension direction of the elastic deformation portion 18) as the second boundary portion 182 of the elastic deformation portion 18. That is, the second connection portion 173 has substantially the same width (width in a direction perpendicular to the direction in which the first boundary portion 181 and the second boundary portion 182 are aligned when viewed from the Z-axis direction) and thickness (thickness in the Z-axis direction) as the second boundary portion 182 of the elastic deformation portion 18. However, the first connecting portion 163 does not have to have substantially the same thickness as the first boundary portion 181 of the elastic deformation portion 18, as long as it has substantially the same width as the first boundary portion 181 of the elastic deformation portion 18. Similarly, the second connecting portion 173 does not have to have substantially the same thickness as the second boundary portion 182 of the elastic deformation portion 18, as long as it has substantially the same width as the second boundary portion 182 of the elastic deformation portion 18. Note that "substantially the same" means that it is within the range of manufacturing tolerance with respect to the design value (reference value).

[0061] The outer edge 160 of the electrode portion 16 when viewed from the Z-axis direction includes a pair of first portions 161 and a pair of second portions 162. The pair of first portions 161 are portions extending from the first connection portion 163 to both sides of the first connection portion 163 (both sides in the circumferential direction) of each elastic deformation portion 18. In other words, the pair of first portions 161 are portions extending along the outer edge 140 of the surface 14a of the light transmission member 14 on both sides of the first connection portion 163. The pair of second portions 162 are portions extending from the pair of first portions 161 to both sides of the pair of first portions 161 (both sides in the circumferential direction) of each elastic deformation portion 18. In other words, the pair of second portions 162 are portions extending along the outer edge 140 of the surface 14a of the light transmission member 14 on both sides of the pair of first portions 161. The surface 14a of the light transmitting member 14 is a first bonding surface (see FIG. 4) that includes a bonding region with the electrode portion 16, and is a flat surface that includes the bonding region with the electrode portion 16. In the Fabry-Perot interference filter 1, the surface 14a is a flat surface that is perpendicular to the Z-axis direction.

[0062] The pair of first portions 161 and the pair of second portions 162 are located inside the outer edge 140 of the surface 14a (i.e., within the surface 14a) when viewed from the Z-axis direction. In the Fabry-Perot interference filter 1, the entire outer edge 160 of the electrode portion 16 is located inside the outer edge 140 of the surface 14a (i.e., within the surface 14a) when viewed from the Z-axis direction. When viewed from the Z-axis direction, the distance D1 between the outer edge 140 of the surface 14a and each first portion 161 is greater than the distance D2 between the outer edge 140 of the surface 14a and each second portion 162. In the Fabry-Perot interference filter 1, the distance D2 is less than half of the distance D1. When the distance between the outer edge 140 of the surface 14a and each first portion 161 varies, the distance D1 refers to the minimum distance between the outer edge 140 of the surface 14a and each first portion 161. When the distance between the outer edge 140 of the surface 14a and each second portion 162 varies, the distance D2 means the maximum value of the distance between the outer edge 140 of the surface 14a and each second portion 162.

[0063] The outer edge 170 of the support portion 17 when viewed from the Z-axis direction includes a pair of third portions 171 and a pair of fourth portions 172. The pair of third portions 171 are portions that extend from the second connection portion 173 to both sides of the second connection portion 173 (both sides in the circumferential direction) with respect to each elastic deformation portion 18. In other words, the pair of third portions 171 are portions that extend along the outer edge 150 of the surface 15a of the support member 15 on both sides of the second connection portion 173. The pair of fourth portions 172 are portions that extend from the pair of third portions 171 to both sides of the pair of third portions 171 (both sides in the circumferential direction) with respect to each elastic deformation portion 18. In other words, the pair of fourth portions 172 are portions that extend along the outer edge 150 of the surface 15a of the support member 15 on both sides of the pair of third portions 171. The surface 15a of the support member 15 is a second bonding surface including the bonding area with the support portion 17 (see FIG. 4), and is a flat surface including the bonding area with the support portion 17. In the Fabry-Perot interference filter 1, the surface 15a is a flat surface perpendicular to the Z-axis direction.

[0064] The pair of third portions 171 and the pair of fourth portions 172 are located inside the outer edge 150 of the surface 15a (i.e., within the surface 15a) when viewed from the Z-axis direction. In the Fabry-Perot interference filter 1, the entire outer edge 170 of the support portion 17 is located inside the outer edge 150 of the surface 15a (i.e., within the surface 15a) when viewed from the Z-axis direction. When viewed from the Z-axis direction, the distance D3 between the outer edge 150 of the surface 15a and each of the third portions 171 is greater than the distance D4 between the outer edge 150 of the surface 15a and each of the fourth portions 172. In the Fabry-Perot interference filter 1, the distance D4 is less than half of the distance D3. When the distance between the outer edge 150 of the surface 15a and each of the third portions 171 varies, the distance D3 means the minimum value of the distance between the outer edge 150 of the surface 15a and each of the third portions 171. When the distance between the outer edge 150 of the surface 15a and each of the fourth portions 172 varies, the distance D4 means the maximum value of the distance between the outer edge 150 of the surface 15a and each of the fourth portions 172.

[0065] 10 , the length L2 of each second portion 162 is greater than the length L1 of each first portion 161. Each of the lengths L1 and L2 is a length in a direction along the outer edge 140 of the surface 14a, and is a length in the circumferential direction in the Fabry-Perot interference filter 1. In the Fabry-Perot interference filter 1, between a pair of elastic deformation portions 18 adjacent to each other in the circumferential direction, the second portion 162 on one elastic deformation portion 18 side and the second portion 162 on the other elastic deformation portion 18 side are continuous, but the second portion 162 on one elastic deformation portion 18 side and the second portion 162 on the other elastic deformation portion 18 side may be separated, for example, by a notch formed in the electrode portion 16 so as to open outward. When the second portion 162 on one elastic deformation portion 18 side and the second portion 162 on the other elastic deformation portion 18 side are continuous between a pair of elastic deformation portions 18 adjacent to each other in the circumferential direction, the length L2 of each second portion 162 is half the length of the continuous pair of second portions 162. When the second portion 162 on one elastic deformation portion 18 side and the second portion 162 on the other elastic deformation portion 18 side are separated between a pair of elastic deformation portions 18 adjacent to each other in the circumferential direction, the length L2 of each second portion 162 is the length of each second portion 162 (for example, when a notch is formed in the electrode portion 16 so as to open outward, the length of each of the pair of second portions 162 on both sides of the notch).

[0066] The length L4 of each fourth portion 172 is greater than the length L3 of each third portion 171. Each of the lengths L3 and L4 is a length in a direction along the outer edge 150 of the surface 15a. In the Fabry-Perot interference filter 1, between a pair of elastic deformation portions 18 adjacent to each other in the circumferential direction, the fourth portion 172 on one elastic deformation portion 18 side and the fourth portion 172 on the other elastic deformation portion 18 side are continuous. However, the fourth portion 172 on one elastic deformation portion 18 side and the fourth portion 172 on the other elastic deformation portion 18 side may be separated, for example, by a notch formed in the support portion 17 so as to open outward. When the fourth portion 172 on one elastic deformation portion 18 side and the fourth portion 172 on the other elastic deformation portion 18 side are continuous between a pair of elastic deformation portions 18 adjacent to each other in the circumferential direction, the length L4 of each fourth portion 172 is half the length of the pair of continuous fourth portions 172. When a pair of elastic deformation portions 18 adjacent to each other in the circumferential direction are separated into a fourth portion 172 on one side of the elastic deformation portion 18 and a fourth portion 172 on the other side of the elastic deformation portion 18, the length L2 of each fourth portion 172 is the length of each fourth portion 172 (for example, when a notch is formed in the support portion 17 so as to open outward, the length of each of the pair of fourth portions 172 on both sides of the notch).

[0067] As shown in FIG. 9 , for each elastic deformation portion 18, a pair of corners C1 formed on both sides of the first connection portion 163 have a continuous curvature. That is, each elastic deformation portion 180 is smoothly connected to the electrode portion 16 via the rounded chamfered surface formed at each corner C1. For each elastic deformation portion 18, a pair of corners C2 formed on both sides of the second connection portion 173 have a continuous curvature. That is, each elastic deformation portion 180 is smoothly connected to the support portion 17 via the rounded chamfered surface formed at each corner C2. In the first layer 10 configured as described above, as shown in FIG. 4 , the thickness T1 of the light transmitting member 14 is greater than the thickness T2 of the semiconductor layer 12. When the thickness of the light transmitting member 14 varies in the Z-axis direction, the thickness T1 refers to the minimum thickness of the light transmitting member 14 in the Z-axis direction. When the thickness of the semiconductor layer 12 varies in the Z-axis direction, the thickness T2 refers to the maximum thickness of the semiconductor layer 12 in the Z-axis direction. [Operation and Effects]

[0068] In the Fabry-Perot interference filter 1, in a configuration in which the electrode unit 16 and the support unit 17 are connected by a plurality of elastic deformation portions 18, the electrode unit 16 is bonded to the light transmitting member 14, and the support unit 17 is bonded to the support member 15, the elastic deformation portions 18, the first connection portion 163 of the electrode unit 16, and the second connection portion 173 of the support unit 17 are configured as elastic deformation portions 180 in the semiconductor layer 12. As a result, even if the bonding position of at least one of the light transmitting member 14 and the support member 15 relative to the semiconductor layer 12 is shifted due to, for example, a manufacturing error, the region of each elastic deformation portion 180 that is actually allowed to elastically deform is likely to be maintained in a predetermined shape as the elastic deformation portion 18. Therefore, according to the Fabry-Perot interference filter 1, the first reflection film 50 can be moved with high precision relative to the second reflection film 60.

[0069] In the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, the first connection portion 163 of the electrode portion 16 has substantially the same width as the first boundary portion 181 of the elastic deformation portion 18, and when viewed from the Z-axis direction, the second connection portion 173 of the support portion 17 has substantially the same width as the second boundary portion 182 of the elastic deformation portion 18. This makes it possible to easily realize a configuration in which the region of the elastic deformation intended portion 180 that is actually allowed to elastically deform can be maintained in a predetermined shape as the elastic deformation portion 18.

[0070] In the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, the outer edge 160 of the electrode unit 16 includes, for each elastic deformation portion 18, a pair of first portions 161 and a pair of second portions 162 located inside the outer edge 140 of the surface 14a of the light transmitting member 14, and the distance D1 between the outer edge 140 of the surface 14a and each first portion 161 is greater than the distance D2 between the outer edge 140 of the surface 14a and each second portion 162. This makes it possible to increase the area of ​​the electrode unit 16, which is the first electrode 19 for generating electrostatic force, while ensuring the length of each elastic deformation portion 180. In particular, in the Fabry-Perot interference filter 1, the distance D2 is less than half of the distance D1, so that the area of ​​the electrode unit 16, which is the first electrode 19 for generating electrostatic force, can be reliably increased.

[0071] In the Fabry-Perot interference filter 1, the length L2 of each second portion 162 is greater than the length L1 of each first portion 161. This ensures that the area of ​​the first electrode 19 for generating an electrostatic force can be increased.

[0072] In the Fabry-Perot interference filter 1, when viewed from the Z-axis direction, the outer edge 170 of the support portion 17 includes, for each elastic deformation portion 18, a pair of third portions 171 and a pair of fourth portions 172 that are located inside the outer edge 150 of the surface 15a of the support member 15, and the distance D3 between the outer edge 150 of the surface 15a and each of the third portions 171 is greater than the distance D4 between the outer edge 150 of the surface 15a and each of the fourth portions 172. Thus, by making the shape of each elastic deformation portion 180 symmetrical on the first connection portion 163 side and the second connection portion 173 side, it is possible to obtain appropriate characteristics for each elastic deformation portion 18. In particular, in the Fabry-Perot interference filter 1, the distance D4 is less than half the distance D3, and the length L4 of each fourth portion 172 is greater than the length L3 of each third portion 171, so that the shape of each elastically deformable portion 180 can be made symmetrical on the first connection portion 163 side and the second connection portion 173 side.

[0073] In the Fabry-Perot interference filter 1, a pair of corners C1 formed on both sides of the first connection portion 163 have a continuous curvature for each elastic deformation portion 18. This makes it possible to suppress stress concentration on the first connection portion 163 due to, for example, the difference in thermal expansion coefficient between the light transmission member 14 and the semiconductor layer 12.

[0074] In the Fabry-Perot interference filter 1, a pair of corners C2 formed on both sides of the second connection portion 173 have a continuous curvature for each elastic deformation portion 18. This makes it possible to suppress stress concentration on the second connection portion 173 due to, for example, a difference in thermal expansion coefficient between the support member 15 and the semiconductor layer 12.

[0075] In the Fabry-Perot interference filter 1, the thickness T1 of the light transmitting member 14 is greater than the thickness T2 of the semiconductor layer 12. This allows the light transmitting member 14 to stably support the first reflective film 50. Furthermore, as the thickness T1 of the light transmitting member 14 increases, there is a risk that the characteristics of each elastically deforming portion 18 will change significantly depending on the bonding state between the light transmitting member 14 and the semiconductor layer 12. However, as described above, the region of each elastically deforming portion 180 that is actually allowed to elastically deform is more likely to maintain a predetermined shape as the elastically deforming portion 18, so the characteristics of the elastically deforming portion 18 can be appropriately maintained. [Method for manufacturing a Fabry-Perot interference filter]

[0076] A method for manufacturing the above-mentioned Fabry-Perot interference filter 1 will be described. First, as shown in FIG. 11A, a first base material layer 110 having a pair of main surfaces 110a and 110b and a second base material layer 120 having a pair of main surfaces 120a and 120b are prepared, and the main surface 110a of the first base material layer 110 and the main surface 120b of the second base material layer 120 are bonded to each other (first step). The first base material layer 110 includes a portion that will become the first substrate 11, i.e., a portion that will become the light transmission member 14 and the support member 15 (see FIG. 4). The first base material layer 110 is a layer made of, for example, a glass substrate. The second base material layer 120 includes a portion that will become the semiconductor layer 12, i.e., a portion that will become the electrode portion 16, the support portion 17, and multiple elastic deformation portions 18. The second base material layer 120 is a layer made of, for example, a silicon substrate. As an example, airtight bonding such as room temperature bonding, plasma activated bonding, or anodic bonding is used to bond the first base material layer 110 and the second base material layer 120. Next, as shown in (b) of Fig. 11, the main surface 120a of the second base material layer 120 is polished, and the second base material layer 120 is thinned.

[0077] Next, as shown in (a) of FIG. 12 , the first base layer 110 is etched (e.g., wet etching) to form the first substrate 11, i.e., the light transmission member 14 and the support member 15 (step 2). Next, as shown in (b) of FIG. 12 , a metal pad 13 is formed on the main surface 120a of the second base layer 120. Next, as shown in (a) of FIG. 13 , the second base layer 120 is etched (e.g., DRIE etching) to form the semiconductor layer 12, i.e., the electrode portion 16, the support portion 17, and a plurality of elastic deformation portions 18 (step 2). Thus, the first layer 10 is obtained. Next, as shown in (b) of FIG. 13 , a first reflective film 50 is formed on the surface 14b of the light transmission member 14.

[0078] Next, as shown in (a) of Figure 14, the second layer 20 is prepared, and the semiconductor layer 12 of the first layer 10 and the second substrate 21 of the second layer 20 are bonded to each other. As an example, the semiconductor layer 12 and the second substrate 21 are bonded together by hermetic bonding such as room temperature bonding, plasma activated bonding, or anodic bonding. Next, as shown in (b) of Figure 14, the third layer 30 provided with the second reflective film 60 and the absorbing film 70 is prepared, and the first substrate 11 of the first layer 10 and the third substrate 31 of the third layer 30 are bonded to each other. As an example, the first substrate 11 and the third substrate 31 are bonded together by hermetic bonding such as room temperature bonding, plasma activated bonding, or anodic bonding. In this manner, a Fabry-Perot interference filter is obtained.

[0079] Note that the formation of the first substrate 11 by etching the first base layer 110 (the step shown in FIG. 12(a)) may be performed after the formation of the semiconductor layer 12 by etching the second base layer 120 (the step shown in FIG. 13(a)). Even in this case, the formation of the metal pads 13 on the main surface 120a of the second base layer 120 (the step shown in FIG. 12(b)) is performed before the formation of the semiconductor layer 12 by etching the second base layer 120 (the step shown in FIG. 13(a)). Furthermore, the formation of the first reflective film 50 on the surface 14b of the light transmitting member 14 (the step shown in FIG. 13(b)) may be performed before the formation of the first substrate 11 by etching the first base layer 110 (the step shown in FIG. 12(a)). In addition, the bonding of the semiconductor layer 12 of the first layer 10 to the second substrate 21 of the second layer 20 (the step shown in (a) of Figure 14) may be performed after the bonding of the first substrate 11 of the first layer 10 to the third substrate 31 of the third layer 30 (the step shown in (b) of Figure 14).

[0080] The above-described manufacturing method for the Fabry-Perot interference filter 1 can easily form a configuration in which the electrode portion 16 and the support portion 17 are connected by a plurality of elastic deformation portions 18, and the electrode portion 16 is bonded to the light transmission member 14, and the support portion 17 is bonded to the support member 15. In this case, even if the bonding position of at least one of the light transmission member 14 and the support member 15 relative to the semiconductor layer 12 is shifted due to, for example, a manufacturing error, the region of each elastic deformation portion 180 that is actually allowed to elastically deform is likely to be maintained in a predetermined shape as the elastic deformation portion 18. Therefore, the above-described manufacturing method for the Fabry-Perot interference filter 1 can obtain a Fabry-Perot interference filter 1 that can move the first reflection film 50 with high precision relative to the second reflection film 60. [Modification]

[0081] The present disclosure is not limited to the above embodiment. For example, the electrode unit 16 may be a portion provided with a first electrode 19 for generating an electrostatic force. As an example, as shown in FIG. 15 , the first electrode 19 may be disposed on one side of the 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 a space in the Z-axis direction. Note that the electrode unit 16 may include any portion that functions as an electrode for generating an electrostatic force or a portion provided with the first electrode 19 for generating an electrostatic force. In other words, in this specification, the electrode unit 16 is an example of a movable portion.

[0082] 16 , the first reflective film 50 may be disposed on the surface 14a of the light-transmitting member 14, and in that case, the second reflective film 60 may be disposed on the surface 21b of the second substrate 21 of the second layer 20. In this example, the first reflective film 50 is surrounded by the electrode portion 16 on the surface 14a of the light-transmitting member 14, and the second reflective film 60 is surrounded by a plurality of second electrodes 22 on the surface 21b of the second substrate 21.

[0083] 17 , the Fabry-Perot interference filter 1 does not necessarily have to include the second layer 20. In this example, the plurality of second electrodes 22 are arranged on the surface 31 a of the third substrate 31 so as to surround the second reflective film 60 when viewed from the Z-axis direction, and the plurality of third electrodes 24 are arranged on the surface 31 b of the third substrate 31 so as to surround the light-transmitting region 1 a when viewed from the Z-axis direction. The second electrodes 22 and the third electrodes 24 are electrically connected to each other via through electrodes 26 provided in the third substrate 31. The metal pad 13 is arranged on the surface 31 b of the third substrate 31. The first electrode 19 and the metal pad 13 are electrically connected to each other via the semiconductor layer 12, the through electrodes 29 provided in the first substrate 11, the frame 41 arranged between the first substrate 11 and the third substrate 31, and the through electrodes 29 provided in the third substrate 31.

[0084] In the semiconductor layer 12, the electrode portion 16 and the support portion 17 may be connected by one elastic deformation portion 18. One elastic deformation portion 18, one first connection portion 163, and one second connection portion 173 configured as one elastic deformation portion 180 may be formed, for example, in a circular ring shape having a thickness (maximum value) smaller than the respective thicknesses (minimum values) of the "portion of the electrode portion 16 other than the first connection portion 163" and the "portion of the support portion 17 other than the second connection portion 173." Even in this case, one elastic deformation portion 180 is a portion designed to elastically deform when the electrode portion 16 moves in the Z-axis direction relative to the support portion 17, and, for example, is a portion having a substantially constant thickness (thickness in the Z-axis direction).

[0085] At the outer edge 160 of the electrode unit 16 when viewed from the Z-axis direction, the first portion 161 may extend from the first connection portion 163 to only one side of the first connection portion 163 with respect to each elastic deformation portion 18, and the second portion 162 may extend from the first portion 161 to only one side of the first portion 161 with respect to each elastic deformation portion 18. In other words, it is sufficient that the first portion 161 extends from the first connection portion 163 to the side opposite the first connection portion 163 with respect to each elastic deformation portion 18, and the second portion 162 extends from the first portion 161 to the side opposite the first connection portion 163 with respect to each elastic deformation portion 18. Even in this case, the area of ​​the electrode unit 16, which is the first electrode 19 for generating electrostatic force, can be increased.

[0086] At the outer edge 170 of the support portion 17 when viewed from the Z-axis direction, the third portion 171 may extend from the second connection portion 173 to only one side of the second connection portion 173 with respect to each elastic deformation portion 18, and the fourth portion 172 may extend from the third portion 171 to only one side of the third portion 171 with respect to each elastic deformation portion 18. In other words, it is sufficient that the third portion 171 extends from the second connection portion 173 to the side opposite the second connection portion 173 with respect to each elastic deformation portion 18, and the fourth portion 172 extends from the third portion 171 to the side opposite the second connection portion 173 with respect to each elastic deformation portion 18. Even in this case, by making the shape of each elastic deformation portion 180 symmetrical on the first connection portion 163 side and the second connection portion 173 side, appropriate characteristics can be obtained for each elastic deformation portion 18.

[0087] 1...Fabry-Perot interference filter, 1a...light transmission region, 10...first layer (movable layer), 10a...movable portion, 12...semiconductor layer (connection layer), 14...light transmission member (movable member), 14a...surface (first bonding surface), 15...support member, 15a...surface (second bonding surface), 16...electrode portion (movable portion), 17...support portion, 18...elastic deformation portion, 19...first electrode (electrode), 50...first reflective film, 60...second reflective film, 110...first base material layer, 110a...main surface, 120...second base material layer, 120b...main surface, 140...outer edge, 150...outer edge, 160...outer edge, 161...first portion, 162...second portion, 163...first connecting portion, 170...outer edge, 171...third portion, 172...fourth portion, 173...second connecting portion, 180...elastically deformable portion, 181...first boundary portion, 182...second boundary portion, C1, C2...corner portion, D1, D2, D2, D3...distance, L1, L2, L2, L3...length, T1, T2...thickness.

Claims

1. A liquid crystal display comprising: a first reflective film; a second reflective film facing the first reflective film via a space in a light transmitting region; and a movable layer supporting the first reflective film in a movable portion movable in a direction in which the first reflective film and the second reflective film face each other, wherein the movable layer includes a movable member which is a part of the movable portion, a support member, and a connection layer joined to each of the movable member and the support member, wherein the connection layer includes a movable portion which is a part of the movable portion and joined to the movable member, a support portion joined to the support member, and an elastic deformation portion connecting the movable portion and the support portion, wherein the movable portion includes a first connection portion connected to a first boundary portion which is an end portion of the elastic deformation portion on the movable portion side and joined to the movable member, and the support portion includes a second connection portion connected to a second boundary portion which is an end portion of the elastic deformation portion on the support portion side and joined to the support member, The Fabry-Perot interference filter, wherein the elastic deformation portion, the first connection portion, and the second connection portion are configured as elastic deformation portions in the connection layer.

2. The Fabry-Perot interference filter according to claim 1, wherein, when viewed from said direction, said first connection portion has substantially the same width as said first boundary portion, and, when viewed from said direction, said second connection portion has substantially the same width as said second boundary portion.

3. The Fabry-Perot interference filter according to claim 1 or 2, wherein the elastic deformation portion is each of a plurality of elastic deformation portions.

4. The Fabry-Perot interference filter according to claim 3, wherein the movable part is an electrode for generating an electrostatic force or a part provided with an electrode for generating an electrostatic force, the movable member has a first bonding surface including a bonding area with the movable part, an outer edge of the movable part when viewed from the direction includes: a first part extending from the first connection part to the opposite side of the first connection part for each of the plurality of elastic deformation parts, and a second part extending from the first part to the opposite side of the first connection part for each of the plurality of elastic deformation parts, the first part and the second part are located inside the outer edge of the first bonding surface when viewed from the direction, and a distance between the outer edge of the first bonding surface and the first part is greater than a distance between the outer edge of the first bonding surface and the second part when viewed from the direction.

5. A Fabry-Perot interference filter as claimed in claim 4, wherein the distance between the outer edge of the first bonding surface and the second portion is less than half the distance between the outer edge of the first bonding surface and the first portion.

6. A Fabry-Perot interference filter according to claim 4 or 5, wherein the length of said second portion is greater than the length of said first portion.

7. A Fabry-Perot interference filter according to any one of claims 4 to 6, wherein the support member has a second bonding surface including a bonding area with the support portion, and an outer edge of the support portion when viewed from the direction includes: a third portion extending from the second connection portion to the opposite side of the second connection portion for each of the plurality of elastic deformation portions, and a fourth portion extending from the third portion to the opposite side of the second connection portion for each of the plurality of elastic deformation portions, the third portion and the fourth portion being located inside the outer edge of the second bonding surface when viewed from the direction, and a distance between the outer edge of the second bonding surface and the third portion is greater than a distance between the outer edge of the second bonding surface and the fourth portion when viewed from the direction.

8. A Fabry-Perot interference filter according to claim 7, wherein the distance between the outer edge of the second bonding surface and the fourth portion is equal to or less than half the distance between the outer edge of the second bonding surface and the third portion.

9. A Fabry-Perot interference filter according to claim 7 or 8, wherein the length of said fourth portion is greater than the length of said third portion.

10. A Fabry-Perot interference filter according to any one of claims 3 to 9, wherein a pair of corners formed on both sides of the first connection portion for each of the plurality of elastic deformation portions have a continuous curvature.

11. A Fabry-Perot interference filter according to any one of claims 3 to 10, wherein a pair of corners formed on both sides of the second connection portion for each of the plurality of elastic deformation portions have a continuous curvature.

12. A Fabry-Perot interference filter according to any one of claims 1 to 11, wherein the thickness of the movable member in said direction is greater than the thickness of the connecting layer in said direction.

13. A method for manufacturing a Fabry-Perot interference filter according to any one of claims 1 to 12, comprising: a first step of preparing a first substrate layer including a portion that will become the movable member and the support member, and a second substrate layer including a portion that will become the connection layer, and bonding a main surface of the first substrate layer to a main surface of the second substrate layer; and a second step of, after the first step, etching the first substrate layer to form the movable member and the support member, and etching the second substrate layer to form the connection layer.

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