Filter unit

Abstract

This filter unit (1) is provided with: a housing (200) that includes a first wall section (210) having a light passage section, a second wall section (220) facing the first wall section (210), and a surrounding section (230) that surrounds a region between the first wall section (210) and the second wall section (220); a Fabry-Perot interference filter (10) that includes a pair of mirror sections that face each other in the first direction and have a variable distance from each other, and that is disposed within the housing (200) so as to overlap the light-passing section when viewed from the first direction; a wiring board (4) which is attached to the housing (200) such that at least a portion thereof is embedded in the surrounding section (230), and which is electrically connected to the Fabry-Perot interference filter (10); and an adhesive member (7) disposed between the wiring board (4) and the housing (200).

Description

Technical Field

[0001] The present disclosure relates to a filter unit including a Fabry - Perot interference filter. Background Art

[0002] In order to configure a filter unit using a Fabry - Perot interference filter including a pair of mirror portions with variable distances from each other, the following structure is considered. That is, a structure including a wiring substrate, a housing disposed on the wiring substrate, a Fabry - Perot interference filter disposed in the housing, a terminal bridging between the wiring substrate and a side wall portion of the housing, and a wire bridging between the Fabry - Perot interference filter and the terminal (for example, refer to Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2015 - 014543 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] However, in the filter unit applying the above - described structure, it is difficult to thin the filter unit in the optical axis direction of the Fabry - Perot interference filter (that is, the direction in which the pair of mirror portions face each other). In addition, it is difficult to perform electrical connection from the side with respect to the optical axis direction of the Fabry - Perot interference filter. Therefore, there is a technical problem that it is not suitable for being disposed in a region narrow in the optical axis direction of the Fabry - Perot interference filter (for example, the region between lenses in a lens barrel).

[0008] An object of the present disclosure is to provide a filter unit suitable for being disposed in a region narrow in the optical axis direction of a Fabry - Perot interference filter.

[0009] Means for Solving the Technical Problem

[0010] A filter unit according to one aspect of the present disclosure may also be [1] "a filter unit including: a housing including a first wall portion having a light - passing portion, a second wall portion opposite to the first wall portion, and an enclosing portion surrounding a region between the first wall portion and the second wall portion; a Fabry - Perot interference filter including a pair of mirror portions facing each other in a first direction and having variable distances from each other, and disposed in the housing so as to overlap with the light - passing portion when viewed from the first direction; a wiring substrate mounted on the housing so that at least a part thereof is buried in the enclosing portion and electrically connected to the Fabry - Perot interference filter; and an adhesive member disposed between the wiring substrate and the housing".

[0011] In the filter unit described in the above [1], the Fabry - Perot interference filter is disposed within the housing, and the wiring substrate is mounted to the housing such that at least a portion of the wiring substrate is embedded in the surrounding portion of the housing. Thus, for example, compared with the configuration in which the housing accommodating the Fabry - Perot interference filter is disposed on the wiring substrate, the filter unit can be made thinner in the first direction which is the optical axis direction of the Fabry - Perot interference filter (i.e., the direction in which the pair of mirror portions face each other). In addition, since the wiring substrate is mounted to the housing such that at least a portion of the wiring substrate is embedded in the surrounding portion of the housing, electrical connection can be implemented from the side with respect to the optical axis direction of the Fabry - Perot interference filter, i.e., the first direction. Moreover, since there is no need to form wiring in the housing, the structure of the housing can be optimized. Therefore, the filter unit described in the above [1] is suitable for being disposed in a region narrow in the optical axis direction of the Fabry - Perot interference filter.

[0012] A filter unit according to one aspect of the present disclosure may also be [2] "the filter unit according to the above [1], wherein the housing includes a support body constituting the first wall portion and the surrounding portion and a light - transmissive member constituting the second wall portion, and the adhesive member is disposed between the wiring substrate and the support body and between the wiring substrate and the light - transmissive member". According to the filter unit described in this [2], an increase in thickness in the first direction which is the optical axis direction of the Fabry - Perot interference filter can be suppressed, and a package for accommodating the Fabry - Perot interference filter is formed by the support body, the wiring substrate, the light - transmissive member, and the adhesive member. Thereby, the Fabry - Perot interference filter can be protected from the influence of moisture, fine particles, etc.

[0013] A filter unit according to one aspect of the present disclosure may also be [3] "the filter unit according to the above [1] or [2], wherein, when viewed from the first direction, the Fabry - Perot interference filter is located at the center of the housing". According to the filter unit described in this [3], even when an external force acts on the housing from the side with respect to the first direction, the external force can be suppressed from reaching the Fabry - Perot interference filter. In addition, for example, by fitting the housing inside a barrel such as a lens barrel, the Fabry - Perot interference filter can be disposed on the center line of the barrel.

[0014] A filter unit according to one aspect of the present disclosure may also be [4] "the filter unit according to the above [3], wherein, when viewed from the first direction, the outer edge of the housing has a circular shape". According to the filter unit described in this [4], even when an external force acts on the housing from the side with respect to the first direction, the external force can be suppressed from reaching the Fabry - Perot interference filter with good balance. In addition, for example, when the barrel is cylindrical, the Fabry - Perot interference filter can be easily and highly accurately disposed on the center line of the cylindrical barrel.

[0015] The filter unit according to one aspect of the present disclosure may also be [5] "the filter unit according to any one of [1] to [4] above, wherein a first recess is defined by the first wall portion and the surrounding portion, the Fabry - Perot interference filter is disposed in the first recess, and when viewed from the first direction, the outer edge of the Fabry - Perot interference filter and the inner edge of the first recess are each rectangular". According to the filter unit described in [5], when viewed from the first direction, the outer edge of the Fabry - Perot interference filter and the inner edge of the first recess are each rectangular, so that the positioning of the Fabry - Perot interference filter relative to the housing can be easily and accurately performed.

[0016] The filter unit according to one aspect of the present disclosure may also be [6] "the filter unit according to any one of [1] to [5] above, wherein the wiring substrate is mounted on the housing so as not to overlap the Fabry - Perot interference filter when viewed from the first direction". According to the filter unit described in [6], the filter unit can be made thinner in the optical axis direction of the Fabry - Perot interference filter, i.e., the first direction.

[0017] The filter unit according to one aspect of the present disclosure may also be [7] "the filter unit according to [6] above, wherein the Fabry - Perot interference filter is disposed on the first mounting surface of the first wall portion, the wiring substrate is disposed on the second mounting surface of the surrounding portion, and the first mounting surface and the second mounting surface are in the same plane". According to the filter unit described in [7], the filter unit can be made thinner in the optical axis direction of the Fabry - Perot interference filter, i.e., the first direction.

[0018] The filter unit according to one aspect of the present disclosure may also be [8] "the filter unit according to any one of [1] to [7] above, wherein a second recess is formed in the surrounding portion, the second recess has the first direction as the depth direction and opens on the side of the second wall portion, the second recess reaches the outer edge of the surrounding portion when viewed from the first direction, and the wiring substrate is disposed in the second recess". According to the filter unit described in [8], electrical connection can be performed from the side in the optical axis direction of the Fabry - Perot interference filter, i.e., the first direction, with a simple structure.

[0019] The filter unit according to one aspect of the present disclosure may also be "[9] The filter unit according to any one of [1] to [8] above, wherein a first recess is defined by the first wall portion and the surrounding portion, a second recess is formed in the surrounding portion, the second recess has the first direction as the depth direction and opens on the side of the second wall portion, the Fabry - Perot interference filter is disposed in the first recess, the wiring substrate is disposed in the second recess, and the housing further includes a partition portion disposed between the first recess and the second recess". According to the filter unit described in [9], positioning of the Fabry - Perot interference filter and the wiring substrate with respect to the housing can be easily and accurately performed with reference to the partition portion.

[0020] The filter unit according to one aspect of the present disclosure may also be "

[10] The filter unit according to any one of [1] to [9] above, wherein a first recess is defined by the first wall portion and the surrounding portion, the Fabry - Perot interference filter is disposed in the first recess, and when viewed from the first direction, the distance from the inner edge of the first recess to the outer edge of the surrounding portion in one direction is greater than the width of the Fabry - Perot interference filter in the one direction". According to the filter unit described in

[10] , even when an external force is applied to the housing from the side with respect to the first direction, the external force can be prevented from reaching the Fabry - Perot interference filter.

[0021] The filter unit according to one aspect of the present disclosure may also be "

[11] The filter unit according to any one of [1] to

[10] above, wherein a first recess is defined by the first wall portion and the surrounding portion, the Fabry - Perot interference filter is disposed in the first recess, the light passing portion is an opening formed in the first wall portion, when viewed from the first direction, the outer edge of the Fabry - Perot interference filter is rectangular, when viewed from the first direction, the distance from the outer edge of the Fabry - Perot interference filter to the outer edge of the surrounding portion in a direction perpendicular to one side of the outer edge of the Fabry - Perot interference filter is greater than the length of the diagonal of the outer edge of the Fabry - Perot interference filter, and when viewed from the first direction, the width of the opening is smaller than the width of the Fabry - Perot interference filter in the direction perpendicular to the one side". According to the filter unit described in

[11] , when viewed from the first direction, the opening becomes very small compared to the housing, so that stray light can be prevented from entering the Fabry - Perot interference filter.

[0022] The filter unit according to one aspect of the present disclosure may also be

[12] "the filter unit according to any one of [1] to

[11] above, wherein a first concave portion is defined by the first wall portion and the surrounding portion, a second concave portion is formed in the surrounding portion, the second concave portion has the first direction as the depth direction and opens on the second wall portion side, the first concave portion and the second concave portion are arranged in a second direction perpendicular to the first direction, the Fabry - Perot interference filter is disposed in the first concave portion, the wiring substrate is disposed in the second concave portion, if the width of the Fabry - Perot interference filter in a third direction perpendicular to both the first direction and the second direction is set as Wf, the width of the wiring substrate in the third direction is set as Ws, the width of the first concave portion in the third direction is set as W1, and the width of the second concave portion in the third direction is set as W2, then the relationship of "Wf ≤ W1 < Ws ≤ W2" or the relationship of "Ws ≤ W2 < Wf ≤ W1" holds." According to the filter unit described in

[12] , since the width W1 of the first concave portion and the width W2 of the second concave portion are different from each other, by using the boundary portion between the first concave portion and the second concave portion as a reference (for example, a mechanical positioning portion or a reference coordinate), it is possible to easily and accurately perform the positioning of the Fabry - Perot interference filter and the wiring substrate with respect to the housing. In addition, compared with the case where the smaller width of the width W1 of the first concave portion and the width W2 of the second concave portion is adjusted to be the same as the larger width, the strength of the housing can be ensured. Further, when the relationship of "Wf ≤ W1 < Ws ≤ W2" holds, even if an external force acts on the wiring substrate from the side with respect to the first direction, the external force can be released from the boundary portion between the first concave portion and the second concave portion to the support body, and the external force can be prevented from affecting the Fabry - Perot interference filter. On the other hand, when the relationship of "Ws ≤ W2 < Wf ≤ W1" holds, it is possible to suppress stray light from entering the Fabry - Perot interference filter through the second concave portion in which the wiring substrate is disposed.

[0023] The filter unit according to one aspect of the present disclosure may also be

[13] "the filter unit according to

[12] above, wherein the relationship of 'Wf = W1' holds." According to the filter unit described in

[13] , it is possible to more easily and accurately perform the positioning of the Fabry - Perot interference filter with respect to the housing.

[0024] The filter unit according to one aspect of the present disclosure may also be

[14] "the filter unit according to

[12] or

[13] above, wherein the relationship of 'Ws = W2' holds." According to the filter unit described in

[14] , it is possible to more easily and accurately perform the positioning of the wiring substrate with respect to the housing.

[0025] The filter unit according to one aspect of the present disclosure may also be "

[15] The filter unit according to any one of [1] to

[14] above, wherein a through hole that opens on the inner surface and the outer surface of the housing is formed in the housing". According to the filter unit described in

[15] , for example, when manufacturing the filter unit, even if gas is generated in the space inside the housing, the gas can be released to the outside through the through hole.

[0026] Advantages of the Invention

[0027] According to the present disclosure, it is possible to provide a filter unit suitable for being disposed in a narrow region in the optical axis direction of a Fabry - Perot interference filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a perspective view of a Fabry - Perot interference filter included in a filter unit according to an embodiment.

[0029] Figure 2 is along Figure 1 a cross - sectional view of the Fabry - Perot interference filter taken along line II - II shown in the figure.

[0030] Figure 3 is a top view of a filter unit according to an embodiment.

[0031] Figure 4 is along Figure 3 a cross - sectional view of the filter unit taken along line IV - IV shown in the figure.

[0032] Figure 5 is a top view of a part of a filter unit according to an embodiment.

[0033] Figure 6 is a top view of a part of a filter unit according to an embodiment.

[0034] Figure 7 is a bottom view of a filter unit according to an embodiment.

[0035] Figure 8 is a cross - sectional view of a lens barrel including a filter unit according to an embodiment.

[0036] Figure 9 is a top view of a part of a filter unit according to a modified example.

[0037] Figure 10 is a cross - sectional view of a part of a lens barrel including a filter unit according to a modified example.

[0038] Figure 11 is a cross - sectional view of a Fabry - Perot interference filter according to a modified example.

[0039] Description of Reference Numerals

[0040] 1... Filter unit; 2... Support; 2b... Surface (outer surface); 3... Light transmissive member; 4... Wiring substrate; 7... Adhesive member; 10, 400... Fabry - Perot interference filter; 10E... Outer edge; 14, 15, 412, 422... Mirror portion; 21... First recess; 21E... Inner edge; 21a... Bottom surface (first placement surface, inner surface); 22... Second recess; 22a... Bottom surface (second placement surface); 23... Opening (light passing portion); 24... Through hole; 26... Partition portion; 200... Housing; 200E... Outer edge; 210... First wall portion; 220... Second wall portion; 230... Enclosing portion. Detailed implementation manners

[0041] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, in each figure, the same or corresponding parts are denoted by the same reference numerals, and repeated descriptions are omitted.

[0042] [Structure of the Fabry - Perot interference filter included in the filter unit]

[0043] As Figure 1 shown, the Fabry - Perot interference filter 10 has a light transmissive region 10a. The Fabry - Perot interference filter 10 is a rectangular plate - shaped element with the Z - axis direction as the thickness direction. The light transmissive region 10a is a cylindrical region having a center line parallel to the Z - axis direction. When viewed from the Z - axis direction, the center of the light transmissive region 10a coincides with the center of the Fabry - Perot interference filter 10.

[0044] As Figure 2 shown, the Fabry - Perot interference filter 10 includes a substrate 11 with the Z - axis direction as the thickness direction. The material of the substrate 11 is, for example, silicon, quartz, glass, etc. The substrate 11 has a pair of surfaces 11a, 11b. The pair of surfaces 11a, 11b face each other in the Z - axis direction. A first stacked structure 12 is stacked on the surface 11a of the substrate 11. A second stacked structure 13 is stacked on the surface 11b of the substrate 11.

[0045] The first stacked structure 12 includes an antireflection layer 121, a first stacked body 122, an intermediate layer 123, and a second stacked body 124. The antireflection layer 121, the first stacked body 122, the intermediate layer 123, and the second stacked body 124 are sequentially stacked on the surface 11a of the substrate 11. A gap (air gap) S is formed between the first stacked body 122 and the second stacked body 124 through the frame-shaped intermediate layer 123. When the material of the substrate 11 is silicon, the materials of the antireflection layer 121 and the intermediate layer 123 are, for example, silicon oxide or the like. The thickness of the intermediate layer 123 is, for example, an integer multiple of 1 / 2 of the designed center wavelength. In addition, the thickness of the intermediate layer 123 may be greater than an integer multiple of 1 / 2 of the designed center wavelength as needed.

[0046] The portion of the first stacked body 122 corresponding to the light transmission region 10a functions as a mirror portion 14. The mirror portion 14 is supported on the substrate 11 via the antireflection layer 121. As an example, the first stacked body 122 is formed by sequentially stacking a plurality of polysilicon layers and a plurality of silicon nitride layers. The optical thickness of each layer constituting the mirror portion 14 is, for example, an integer multiple of 1 / 4 of the designed center wavelength. In addition, a silicon oxide layer may be used instead of the silicon nitride layer.

[0047] The portion of the second stacked body 124 corresponding to the light transmission region 10a functions as a mirror portion 15. The mirror portion 15 is supported on the substrate 11 via the antireflection layer 121, the first stacked body 122, and the intermediate layer 123, and faces the mirror portion 14 via the gap S. As an example, the second stacked body 124 is formed by sequentially stacking a plurality of polysilicon layers and a plurality of silicon nitride layers. The optical thickness of each layer constituting the mirror portion 15 is, for example, an integer multiple of 1 / 4 of the designed center wavelength. In addition, a silicon oxide layer may be used instead of the silicon nitride layer. In addition, in the portion of the second stacked body 124 corresponding to the gap S, a plurality of through holes are formed to such an extent that the function of the mirror portion 15 is not substantially affected. The plurality of through holes are used when forming the gap S by etching away a part of the intermediate layer 123.

[0048] A first electrode 125 and a second electrode 126 are formed on the mirror portion 14. The first electrode 125 surrounds the light transmission region 10a when viewed from the Z-axis direction. When viewed from the Z-axis direction, the second electrode 126 overlaps with the light transmission region 10a. The shape of the second electrode 126 when viewed from the Z-axis direction is substantially the same as the shape of the light transmission region 10a when viewed from the Z-axis direction. The first electrode 125 and the second electrode 126 are respectively formed by doping impurities in a part of the polysilicon layer to make that part have a low resistance.

[0049] The third electrode 127 is formed on the mirror section 15. The third electrode 127 faces the first electrode 125 and the second electrode 126 with a gap S therebetween. The third electrode 127 is formed by doping impurities in a part of the polysilicon layer to make that part have a low resistance. As an example, the distance between the second electrode 126 and the third electrode 127 and the distance between the first electrode 125 and the third electrode 127 are substantially the same.

[0050] In the first stacked structure 12, a pair of terminals 16 are provided so as to sandwich the light transmission region 10a (see Figure 1 ). Each terminal 16 is arranged in a through hole formed in the second stacked body 124 and the intermediate layer 123 so as to open on the side opposite to the substrate 11 and reach the first stacked body 122. Each terminal 16 is electrically connected to the first electrode 125 via a wiring 125a.

[0051] In the first stacked structure 12, a pair of terminals 17 are provided so as to sandwich the light transmission region 10a (see Figure 1 ). Each terminal 17 is arranged in a through hole formed in the second stacked body 124 and the intermediate layer 123 so as to open on the side opposite to the substrate 11 and reach the intermediate layer 123. Each terminal 17 is electrically connected to the second electrode 126 via a wiring 126a and is also electrically connected to the third electrode 127 via a wiring 127a. In addition, the direction in which the pair of terminals 17 sandwich the light transmission region 10a is perpendicular to the direction in which the pair of terminals 16 sandwich the light transmission region 10a (see Figure 1 ).

[0052] A pair of grooves 122a are formed in the first stacked body 122. Each groove 122a extends in a ring shape so as to surround a part of the wiring 126a that extends in the Z-axis direction from each terminal 17. Each groove 122a electrically insulates the first electrode 125 from the wiring 126a. A groove 122b is formed in the first stacked body 122. The groove 122b extends in a ring shape along the inner edge of the first electrode 125. The groove 122b electrically insulates the first electrode 125 from the second electrode 126. The regions in each of the grooves 122a and 122b may be filled with an insulating material or may be a gap.

[0053] A pair of grooves 124a are formed in the second stacked body 124. Each groove 124a extends in a ring shape so as to surround each terminal 16. Each groove 124a electrically insulates each terminal 16 from the third electrode 127. The regions in each of the grooves 124a may be filled with an insulating material or may be a gap.

[0054] The second stacked structure 13 includes an antireflection layer 131, a third stacked body 132, an intermediate layer 133, and a fourth stacked body 134. The antireflection layer 131, the third stacked body 132, the intermediate layer 133, and the fourth stacked body 134 are sequentially stacked on the surface 11b of the substrate 11. The antireflection layer 131 and the intermediate layer 133 have the same structures as the antireflection layer 121 and the intermediate layer 123, respectively. The third stacked body 132 and the fourth stacked body 134 have stacked structures that are symmetric with respect to the first stacked body 122 and the second stacked body 124 with the substrate 11 as a reference. The antireflection layer 131, the third stacked body 132, the intermediate layer 133, and the fourth stacked body 134 have a function of suppressing warping of the substrate 11.

[0055] In the third stacked body 132, the intermediate layer 133, and the fourth stacked body 134, an opening 18 is formed so as to include the light transmission region 10a. The opening 18 overlaps the light transmission region 10a when viewed from the Z-axis direction. The shape of the opening 18 when viewed from the Z-axis direction is substantially the same as the shape of the light transmission region 10a when viewed from the Z-axis direction. That is, the center line of the opening 18 coincides with the center line of the light transmission region 10a. The opening 18 opens on the side opposite to the substrate 11 and reaches the antireflection layer 131.

[0056] A light shielding layer 135 is formed on the surface of the fourth stacked body 134 on the side opposite to the substrate 11. The material of the light shielding layer 135 is, for example, aluminum or the like. A protective layer 136 is formed on the surface of the light shielding layer 135 and the inner surface of the opening 18. The material of the protective layer 136 is, for example, alumina or the like. In addition, by making the thickness of the protective layer 136 100 nm or less (preferably about 30 nm), the optical influence caused by the protective layer 136 can be ignored.

[0057] In the Fabry - Perot interference filter 10 configured as described above, if a potential difference is generated between the first electrode 125 and the third electrode 127 by applying a voltage to the first electrode 125 and the third electrode 127 via a plurality of terminals 16 and 17, an electrostatic force corresponding to the potential difference is generated between the first electrode 125 and the third electrode 127. By generating an electrostatic force between the first electrode 125 and the third electrode 127, the mirror portion 15 is attracted to the mirror portion 14, and the distance between the mirror portion 14 and the mirror portion 15 is adjusted. At this time, the second electrode 126 having the same potential as the third electrode 127 functions as a compensation electrode, and the mirror portion 15 remains flat in the light transmission region 10a.

[0058] Thus, in the Fabry-Perot interference filter 10, a pair of mirror portions 14 and 15 facing each other in the Z-axis direction function as a pair of mirror portions with variable distance from each other. Here, the wavelength of the light transmitted through the Fabry-Perot interference filter 10 depends on the distance between the mirror portion 14 and the mirror portion 15. Therefore, by adjusting the voltage applied to the first electrode 125 and the third electrode 127 (the potential difference generated between the first electrode 125 and the third electrode 127), the wavelength of the light transmitted through the Fabry-Perot interference filter 10 can be selected.

[0059] [Structure of Filter Unit]

[0060] As Figure 3 and Figure 4 shown, the filter unit 1 includes a support 2, a light transmissive member 3, a wiring substrate 4, a connector 5, a cover 6, and the above-described Fabry-Perot interference filter 10. Further, in Figure 3 , the light transmissive member 3 and the adhesive members 73 and 75 described later are indicated by double-dashed lines.

[0061] The support 2 is a circular plate-shaped member with the Z-axis direction (the first direction) as the thickness direction. That is, when viewed from the Z-axis direction, the outer edge 2E of the support 2 is circular. The support 2 has a pair of surfaces 2a and 2b and a side surface 2c. The pair of surfaces 2a and 2b face each other in the Z-axis direction. The side surface 2c connects the outer edge of the surface 2a and the outer edge of the surface 2b. The material of the support 2 is, for example, a metal material such as stainless steel or a resin material. The outer diameter of the support 2 is, for example, 20 mm to 50 mm. The thickness of the support 2 in the Z-axis direction is, for example, 2 mm to 5 mm.

[0062] As Figure 4 and Figure 5 shown, a first recess 21 and a second recess 22 are formed in the support 2. The first recess 21 and the second recess 22 open on the surface 2a side with the Z-axis direction as the depth direction. The bottom surface (the first placement surface) 21a of the first recess 21 and the bottom surface (the second placement surface) 22a of the second recess 22 are located in the same plane perpendicular to the Z-axis direction. The thickness from the bottom surfaces 21a and 22a to the surface 2b of the support 2 in the Z-axis direction is, for example, about 100 μm. The first recess 21 and the second recess 22 are arranged in the X-axis direction (the second direction perpendicular to the first direction). Further, in Figure 5 , the illustration of the light transmissive member 3 and the adhesive members 73 and 75 described later is omitted.

[0063] The first recess 21 includes the center C of the support body 2 when viewed from the Z-axis direction. When viewed from the Z-axis direction, the first recess 21 does not reach the outer edge 2E of the support body 2. When viewed from the Z-axis direction, the inner edge 21E of the first recess 21 is rectangular. In the present embodiment, when viewed from the Z-axis direction, the inner edge 21E of the first recess 21 is rectangular with the X-axis direction as the long side direction. The width of the first recess 21 in the X-axis direction is, for example, 5 mm to 20 mm. The width of the first recess 21 in the Y-axis direction is, for example, 2.2 mm to 22 mm. The depth of the first recess 21 in the Z-axis direction is, for example, 0.2 mm to 2 mm.

[0064] The second recess 22 does not include the center C of the support body 2 when viewed from the Z-axis direction. The second recess 22 reaches the outer edge 2E of the support body 2 when viewed from the Z-axis direction. When viewed from the Z-axis direction, the inner edge 22E of the second recess 22 is rectangular. In the present embodiment, when viewed from the Z-axis direction, the inner edge 22E of the second recess 22 is rectangular with the X-axis direction as the long side direction. In the present embodiment, the second recess 22 reaches the side surface 2c of the support body 2 on the side opposite to the first recess 21 in the X-axis direction. When viewed from the Z-axis direction, the second recess 22 reaches the outer edge 2E of the support body 2 on the short side of the second recess 22. When viewed from the Z-axis direction, the second recess 22 does not cross the support body 2, so the rigidity of the support body 2 is higher than that of a structure in which the second recess 22 crosses the support body 2. The width of the second recess 22 in the X-axis direction is, for example, 8 mm to 23 mm. The width of the second recess 22 in the Y-axis direction is, for example, 3 mm to 24 mm. The depth of the second recess 22 in the Z-axis direction is, for example, 0.2 mm to 2 mm.

[0065] The width W2 of the second recess 22 in the Y-axis direction (the third direction perpendicular to the first direction and the second direction) is greater than the width W1 of the first recess 21 in the Y-axis direction. In the present embodiment, when viewed from the Z-axis direction, the center line of the first recess 21 parallel to the X-axis direction passes through the center C of the support body 2. In the present embodiment, when viewed from the Z-axis direction, the center line of the second recess 22 parallel to the X-axis direction coincides with the center line of the first recess 21 parallel to the X-axis direction.

[0066] An opening portion (light passing portion) 23 and a through hole 24 are formed in the support body 2. The opening portion 23 and the through hole 24 open on the bottom surface (inner surface) 21a of the first concave portion 21 and the surface (outer surface) 2b of the support body 2, respectively. That is, the first concave portion 21 opens on the side opposite to the opening portion 23 with the Z-axis direction as the depth direction. The opening portion 23 and the through hole 24 are arranged in the X-axis direction. The opening portion 23 defines a cylindrical space having a center line parallel to the Z-axis direction. When viewed from the Z-axis direction, the center of the opening portion 23 coincides with the center C of the support body 2. The inner diameter of the opening portion 23 is, for example, 2 mm to 15 mm.

[0067] A widened portion 25 is formed in the support body 2. The widened portion 25 widens toward the side opposite to the second concave portion 22 in the X-axis direction and both sides in the Y-axis direction with respect to the opening of the first concave portion 21. The widened portion 25 is formed as a concave portion of the support body 2 so as to open on the surface 2a side with the Z-axis direction as the depth direction and reach the opening of the first concave portion 21. In the present embodiment, the width of the widened portion 25 in the Y-axis direction is equal to the width W2 of the second concave portion 22 in the Y-axis direction.

[0068] The support body 2 includes a partition portion 26. The partition portion 26 is disposed between the first concave portion 21 and the second concave portion 22. The partition portion 26 is integrally formed with other portions of the support body 2 as a part of the support body 2. In the present embodiment, the partition portion 26 is a wall portion extending in the Y-axis direction between the bottom surface 21a of the first concave portion 21 and the bottom surface 22a of the second concave portion 22. In the present embodiment, when taking the plane where the bottom surface 21a and the bottom surface 22a are located as a reference, the height of the partition portion 26 in the Z-axis direction is lower than the height of the surface 2a of the support body 2 in the Z-axis direction and lower than the height of the bottom surface 25a of the widened portion 25 in the Z-axis direction. The width of the partition portion 26 in the X-axis direction is, for example, 0.5 mm to 5 mm. The height of the partition portion 26 in the Z-axis direction is, for example, 0.1 mm to 2 mm.

[0069] The Fabry - Perot interference filter 10 is arranged on the support 2 with the Z - axis direction as the thickness direction so as to overlap with the opening 23 when viewed from the Z - axis direction. More specifically, the Fabry - Perot interference filter 10 is arranged in the first recess 21 with the Z - axis direction as the thickness direction so as to overlap with the opening 23 when viewed from the Z - axis direction. The Fabry - Perot interference filter 10 contacts the partition portion 26 within the first recess 21. In the present embodiment, with the bottom surface 21a of the first recess 21 as a reference, the height of the Fabry - Perot interference filter 10 in the Z - axis direction is lower than the height of the surface 2a of the support 2 in the Z - axis direction and lower than the height of the bottom surface 25a of the widened portion 25 in the Z - axis direction. In the present embodiment, with the bottom surface 21a of the first recess 21 as a reference, the height of the partition portion 26 in the Z - axis direction is equal to or less than the height of the Fabry - Perot interference filter 10 in the Z - axis direction. The width of the Fabry - Perot interference filter 10 in the X - axis direction is, for example, 2 mm to 20 mm. The width of the Fabry - Perot interference filter 10 in the Y - axis direction is, for example, 2 mm to 20 mm. The thickness of the Fabry - Perot interference filter 10 in the Z - axis direction is, for example, 300 μm to 650 μm.

[0070] As described above, the Fabry - Perot interference filter 10 is a rectangular plate - shaped element with the Z - axis direction as the thickness direction. Therefore, when viewed from the Z - axis direction, the outer edge 10E of the Fabry - Perot interference filter 10 is rectangular. The Fabry - Perot interference filter 10 is arranged on the bottom surface 21a of the first recess 21 such that each side of the outer edge 10E is parallel to the X - axis direction or the Y - axis direction and the opening 18 faces the opening 23 when viewed from the Z - axis direction. The center line of the opening 18 coincides with the center line of the opening 23. That is, when viewed from the Z - axis direction, the Fabry - Perot interference filter 10 is located at the center C of the support 2. When viewed from the Z - axis direction, the opening 18 is located inside the opening 23.

[0071] The Fabry - Perot interference filter 10 is fixed to the bottom surface 21a by the bonding member 71. The bonding member 71 is arranged in a dot - like manner between the bottom surface 21a and one corner of the Fabry - Perot interference filter 10. Thereby, the stress wave caused by the deformation of the support 2 and / or the bonding member 71 accompanying temperature change can be suppressed from reaching the Fabry - Perot interference filter 10. The material of the bonding member 71 is, for example, a polyimide - based resin, a silicone resin, an epoxy - based resin, an acrylic - based resin, or a mixed resin thereof.

[0072] As Figure 4 and Figure 6As shown, the light-transmitting member 3 is disposed on the support body 2 with the Z-axis direction as the thickness direction so as to cover the opening of the first recess 21. More specifically, the light-transmitting member 3 is disposed in the widened portion 25 with the Z-axis direction as the thickness direction so as to cover the opening of the first recess 21. In the present embodiment, the light-transmitting member 3 covers the opening of the first recess 21 and a part of the opening of the second recess 22. In the present embodiment, when the bottom surface 25a of the widened portion 25 is used as a reference, the height of the light-transmitting member 3 in the Z-axis direction is lower than the height of the surface 2a of the support body 2 in the Z-axis direction.

[0073] The light-transmitting member 3 is a rectangular plate-like member with the Z-axis direction as the thickness direction and the X-axis direction as the length direction. Therefore, when viewed from the Z-axis direction, the outer edge 3E of the light-transmitting member 3 has a rectangular shape with the X-axis direction as the long side direction. The light-transmitting member 3 is disposed on the bottom surface 25a of the widened portion 25 such that each side of the outer edge 3E is parallel to the X-axis direction or the Y-axis direction when viewed from the Z-axis direction. As an example, the light-transmitting member 3 is a band-pass filter that transmits light in a specified wavelength range.

[0074] The light-transmitting member 3 is fixed to the bottom surface 25a and the side surface 25b of the widened portion 25 by the adhesive members 72 and 73. The adhesive member 72 is disposed in a dot shape between the bottom surface 25a and one corner portion of the light-transmitting member 3. The adhesive member 73 is disposed along the corner portion formed by the side surface 25b and the surface 3a of the light-transmitting member 3. The surface 3a is the surface of the light-transmitting member 3 on the side opposite to the first recess 21. A part of the adhesive member 73 also enters between the side surface 25b of the widened portion 25 and the side surface of the light-transmitting member 3. The materials of the adhesive members 72 and 73 are, for example, polyimide-based resins, silicone resins, epoxy-based resins, acrylic resins, or their mixed resins.

[0075] As Figure 4 and Figure 5 shown, the wiring substrate 4 is disposed on the support body 2 with the Z-axis direction as the thickness direction so as not to overlap with the Fabry-Perot interference filter 10 when viewed from the Z-axis direction. More specifically, the wiring substrate 4 is disposed in the second recess 22 with the Z-axis direction as the thickness direction so as not to overlap with the Fabry-Perot interference filter 10 when viewed from the Z-axis direction. The wiring substrate 4 contacts the partition portion 26 in the second recess 22. In the present embodiment, when the bottom surface 22a of the second recess 22 is used as a reference, the height of the wiring substrate 4 in the Z-axis direction is lower than the height of the surface 2a of the support body 2 in the Z-axis direction and lower than the height of the bottom surface 25a of the widened portion 25 in the Z-axis direction. In the present embodiment, when the bottom surface 22a of the second recess 22 is used as a reference, the height of the partition portion 26 in the Z-axis direction is equal to or lower than the height of the wiring substrate 4 in the Z-axis direction.

[0076] The wiring substrate 4 is a rectangular plate-shaped substrate with the Z-axis direction as the thickness direction and the X-axis direction as the long side direction. Therefore, when viewed from the Z-axis direction, the outer edge 4E of the wiring substrate 4 has a rectangular shape with the X-axis direction as the long side direction. The wiring substrate 4 is arranged on the bottom surface 22a of the second recess 22 such that each side of the outer edge 4E is parallel to the X-axis direction or the Y-axis direction when viewed from the Z-axis direction.

[0077] The wiring substrate 4 is fixed to the bottom surface 22a of the second recess 22 by an adhesive member 74. The adhesive member 74 includes a pair of first portions 74a and a second portion 74b. The pair of first portions 74a face each other between the bottom surface 22a and the wiring substrate 4 and extend along the X-axis direction respectively. A part of each first portion 74a also enters between the side surface of the second recess 22 and the side surface of the wiring substrate 4. The second portion 74b faces the partition portion 26 between the bottom surface 22a and the wiring substrate 4 and extends in the Y-axis direction. The material of the adhesive member 74 is, for example, a polyimide resin, a silicone resin, an epoxy resin, an acrylic resin, or a mixed resin thereof.

[0078] The wiring substrate 4 is electrically connected to the Fabry - Perot interference filter 10. More specifically, the terminal 41 of the wiring substrate 4 is electrically connected to the terminal 16 of the pair of terminals 16 of the Fabry - Perot interference filter 10 that is close to the partition portion 26 through a wire 8, and the terminal 42 of the wiring substrate 4 is electrically connected to the terminal 17 of the pair of terminals 17 of the Fabry - Perot interference filter 10 that is close to the partition portion 26 through a wire 8. The pair of terminals 41, 42 are arranged in a region along the partition portion 26 on the surface 4a of the wiring substrate 4 on the side of the light transmissive member 3. Each wire 8 passes through the gap between the partition portion 26 and the light transmissive member 3. When viewed from the X-axis direction, each wire 8 is accommodated in the first recess 21 and the second recess 22. The width of the partition portion 26 in the X-axis direction is smaller than the width of the Fabry - Perot interference filter 10 in the X-axis direction. Thereby, the distance between the Fabry - Perot interference filter 10 and the wiring substrate 4 can be shortened.

[0079] The connector 5 is mounted on the surface 4a of the wiring substrate 4 and is electrically connected to the wiring substrate 4. A part 5a of the connector 5 is located at a position outside the side surface 2c of the support body 2 via a region in the second recess 22 that reaches the side surface 2c of the support body 2. A connection port 51 that opens on the side opposite to the center C of the support body 2 is provided in a part 5a of the connector 5. The connector 5 is accommodated in the second recess 22 in the Z-axis direction. In the filter unit 1, a voltage is applied to the pair of terminals 16, 17 from an external wiring connected to the connector 5 via the wiring substrate 4 and a pair of wires 8.

[0080] As Figure 4 and Figure 6As shown, an adhesive member 75 is disposed between the wiring substrate 4 and the light transmissive member 3. The adhesive member 75 extends along a portion of the outer edge 3E of the light transmissive member 3 that overlaps with the wiring substrate 4 when viewed from the Z-axis direction. The adhesive member 75 seals the gap between the wiring substrate 4 and the light transmissive member 3 outside (on the side opposite to the center C of the support 2) of the pair of terminals 41 and 42. The material of the adhesive member 75 is, for example, a polyimide resin, a silicone resin, an epoxy resin, an acrylic resin, or a mixed resin thereof. In addition, in the present embodiment, the adhesive members 74 and 75 constitute the "adhesive member 7 disposed between the wiring substrate 4 and the support 2 and between the wiring substrate 4 and the light transmissive member 3".

[0081] As Figure 4 and Figure 7 shown, the cover 6 is disposed on the surface 2b of the support 2 so as to cover the opening 23 and the through hole 24. The cover 6 is a plate-like member having light transmissivity and is disposed on the surface 2b of the support 2 with the Z-axis direction as the thickness direction. As an example, the cover 6 is in the shape of a circular plate, and when viewed from the Z-axis direction, the outer edge 6E of the cover 6 is located inside the outer edge 2E of the support 2. The cover 6 is fixed to the surface 2b by an adhesive member 76 disposed along the outer edge 6E of the cover 6. The material of the adhesive member 76 is, for example, a polyimide resin, a silicone resin, an epoxy resin, an acrylic resin, or a mixed resin thereof. A light-shielding film 61 is provided on the surface 6a of the cover 6 opposite to the support 2. The light-shielding film 61 overlaps with the through hole 24 when viewed from the Z-axis direction. The light-shielding film 61 has a size sufficient to prevent light from entering the through hole 24 via the cover 6. The light-shielding film 61 is, for example, a chromium coating film.

[0082] As Figure 4 shown, in the filter unit 1, the support 2 and the light transmissive member 3 constitute a housing 200 including a first wall portion 210, a second wall portion 220, and an enclosing portion 230. More specifically, a part of the support 2 constitutes the first wall portion 210, and a part of the light transmissive member 3 constitutes the second wall portion 220. Another part of the support 2 and another part of the light transmissive member 3 constitute the enclosing portion 230. The first wall portion 210 is a wall portion having an opening 23. Specifically, it is a portion of the support 2 that overlaps with the area inside the first recess 21 when viewed from the Z-axis direction (i.e., the bottom wall portion of the first recess 21). The second wall portion 220 is a wall portion opposite to the first wall portion 210 in the Z-axis direction. Specifically, it is a portion of the light transmissive member 3 that overlaps with the area inside the first recess 21 when viewed from the Z-axis direction. The enclosing portion 230 is a portion that encloses the area between the first wall portion 210 and the second wall portion 220. Specifically, it is a portion of the support 2 and the light transmissive member 3 that encloses the area inside the first recess 21 when viewed from the Z-axis direction.

[0083] Therefore, in the filter unit 1, as described below. The first recess 21 is defined by the first wall portion 210 and the surrounding portion 230. The area within the first recess 21 corresponds to the area within the housing 200. The second recess 22 is formed in the surrounding portion 230 so as to open on the side of the second wall portion 220 with the Z-axis direction as the depth direction. When viewed from the Z-axis direction, the outer edge 200E of the housing 200 coincides with the outer edge 2E of the support 2 (see Figure 3 ). The wiring substrate 4 is mounted on the housing 200 so as not to overlap the Fabry-Perot interference filter 10 when viewed from the Z-axis direction. The wiring substrate 4 is mounted on the housing 200 in such a manner that the entire wiring substrate 4 is buried in the surrounding portion 230. In addition, "the entire wiring substrate 4 is buried in the surrounding portion 230" means that when viewed from any one of the X-axis direction, the Y-axis direction, and the Z-axis direction, the entire wiring substrate 4 overlaps with the surrounding portion 230. At least a part of the wiring substrate 4 is exposed to the outside of the housing 200. In the present embodiment, at least a part of the wiring substrate 4 is exposed to the outside of the housing 200 through the region in the opening of the second recess 22 that is not covered by the light transmissive member 3 and the region in the second recess 22 that reaches the side surface 2c of the support 2.

[0084] As Figure 5 shown, the width Wf of the Fabry-Perot interference filter in the Y-axis direction is equal to or less than the width W1 of the first recess in the Y-axis direction. The width Ws of the wiring substrate in the Y-axis direction is greater than the width W1 of the first recess in the Y-axis direction and equal to or less than the width W2 of the second recess in the Y-axis direction. Therefore, in the filter unit 1, the relationship of "Wf ≤ W1 < Ws ≤ W2" holds. In the present embodiment, the relationships of "Wf = W1" and "Ws = W2" hold. In the filter unit 1, it is preferable that the relationship of "W1 < 2Wf" holds. In addition, in the filter unit 1, it is preferable that the relationship of "W2 < 2Ws" holds.

[0085] Furthermore, "Wf = W1" means that Wf and W1 are substantially equal, and "Ws = W2" means that Ws and W2 are substantially equal. As an example, "Wf = W1" means that W1 is a value greater than or equal to "Wf" and less than or equal to "1.1Wf", and "Ws = W2" means that W2 is a value greater than or equal to "Ws" and less than or equal to "1.1Ws".

[0086] As Figure 3As shown, when viewed from the Z-axis direction, the "distance D1 from the inner edge 21E of the first recess 21 to the outer edge 2E of the support 2" in the Y-axis direction (one direction) is greater than the width Wf of the Fabry-Perot interference filter 10 in the Y-axis direction. The thickness of the "portion from the inner edge 21E of the first recess 21 to the outer edge 2E of the support 2" in the Y-axis direction is greater than the thickness of the Fabry-Perot interference filter 10. When viewed from the Z-axis direction, the "distance D2 from the outer edge 10E of the Fabry-Perot interference filter 10 to the outer edge 2E of the support 2" in the Y-axis direction (the direction perpendicular to one side of the outer edge 10E of the Fabry-Perot interference filter 10) is greater than the length L of the diagonal of the outer edge 10E of the Fabry-Perot interference filter 10. The "distance D2 from the outer edge 10E of the Fabry-Perot interference filter 10 to the outer edge 2E of the support 2" in the Y-axis direction can be about 2 to 3 times the length L of the diagonal of the outer edge 10E of the Fabry-Perot interference filter 10. When viewed from the Z-axis direction, the width W3 of the opening 23 is smaller than the width Wf of the Fabry-Perot interference filter 10 in the Y-axis direction. The "distance D2 from the outer edge 10E of the Fabry-Perot interference filter 10 to the outer edge 2E of the support 2" is about 2 to 3 times the length L of the diagonal of the outer edge 10E of the Fabry-Perot interference filter 10, and the wide "distance D2 from the outer edge 10E of the Fabry-Perot interference filter 10 to the outer edge 2E of the support 2" surrounds the opening 23. The support 2 formed integrally without combining a plurality of components includes a thick wall portion surrounding the first recess 21 and the second recess 22. The thick wall portion is the portion of the support 2 where the thickness in the Z-axis direction is greater than the depth of the first recess 21 in the Z-axis direction. The area of the thick wall portion when viewed from the Z-axis direction is 50% or more of the area of the support 2 when viewed from the Z-axis direction.

[0087] In addition, the "distance D1 from the inner edge 21E of the first recess 21 to the outer edge 2E of the support 2" in a specified direction corresponds to the "distance from the inner edge to the outer edge of the surrounding portion 230" in the specified direction. Further, the "distance D2 from the outer edge 10E of the Fabry-Perot interference filter 10 to the outer edge 2E of the support 2" in the specified direction corresponds to the "distance from the outer edge 10E of the Fabry-Perot interference filter 10 to the outer edge of the surrounding portion 230" in the specified direction.

[0088] [Manufacturing method of the filter unit]

[0089] Refer to Figure 4A method for manufacturing the filter unit 1 will be described. First, a support 2 is prepared, and a pre-cured bonding member 71 is disposed on the bottom surface 21a of the first recess 21, and a pre-cured bonding member 74 is disposed on the bottom surface 22a of the second recess 22. Next, a Fabry-Perot interference filter 10 is disposed on the bottom surface 21a of the first recess 21, and a wiring substrate 4 is disposed on the bottom surface 22a of the second recess 22. A connector 5 is pre-mounted on the surface 4a of the wiring substrate 4. Next, the bonding members 71 and 74 are cured. At this time, the Fabry-Perot interference filter 10 is fitted into the first recess 21 while being in contact with the partition portion 26, so that it is accurately positioned with respect to the opening portion 23. In addition, the wiring substrate 4 is fitted into the second recess 22 while being in contact with the partition portion 26, so that it is accurately positioned with respect to the Fabry-Perot interference filter 10. Next, the terminal 41 of the wiring substrate 4 is electrically connected to the terminal 16 of the Fabry-Perot interference filter 10 through a wire 8, and the terminal 42 of the wiring substrate 4 is electrically connected to the terminal 17 of the Fabry-Perot interference filter 10 through a wire 8. The accurate positioning of the wiring substrate 4 with respect to the Fabry-Perot interference filter 10 is important for reliably performing wire bonding between the Fabry-Perot interference filter 10 and the wiring substrate 4. Among the pair of terminals 16, the terminal 16 to which the wire 8 is connected is located closer to the partition portion 26 (wiring substrate 4) than the center of the Fabry-Perot interference filter 10. Similarly, among the pair of terminals 17, the terminal 17 to which the wire 8 is connected is located closer to the partition portion 26 (wiring substrate 4) than the center of the Fabry-Perot interference filter 10. Thereby, the length of each wire 8 can be shortened.

[0090] Next, a pre-cured bonding member 72 is disposed on the bottom surface 25a of the widened portion 25. Next, an optical transmission member 3 is disposed on the bottom surface 25a of the widened portion 25. Next, the bonding member 72 is cured. Next, a pre-cured bonding member 73 is disposed along the corner formed by the side surface 25b of the widened portion 25 and the surface 3a of the optical transmission member 3, and a pre-cured bonding member 75 is disposed between the wiring substrate 4 and the optical transmission member 3. Next, the bonding members 73 and 75 are cured. At this time, the gas generated from the bonding members 73 and 75 is released to the outside from the inside of the first recess 21 through the through-hole 24. Next, a cover 6 is disposed on the surface 2b of the support 2. Next, a pre-cured bonding member 76 is disposed along the outer edge 6E of the cover 6. Next, the bonding member 76 is cured. A light-shielding film 61 is pre-set on the surface 6a of the cover 6. Through the above, the filter unit 1 can be obtained.

[0091] [Structure of a lens barrel having a filter unit]

[0092] As Figure 8As shown, the lens barrel 300 includes a barrel body 310, a condensing optical system 320 including a plurality of lenses, an imaging optical system 330 including a plurality of lenses, and the above-mentioned filter unit 1. The lens barrel 300 serves as an interchangeable lens of a hyperspectral camera. A hyperspectral camera is a camera that can split light into dozens to hundreds of bands and acquire images for each band.

[0093] The barrel body 310 includes a main body portion 311 and a base end portion 312. The main body portion 311 holds the condensing optical system 320, the imaging optical system 330, and the filter unit 1. The base end portion 312 is configured to be detachable from and attachable to the camera body of the hyperspectral camera.

[0094] The condensing optical system 320 is disposed in a region on the side opposite to the base end portion 312 in the inner region of the main body portion 311. The imaging optical system 330 is disposed in a region on the base end portion 312 side in the inner region of the main body portion 311. The filter unit 1 is disposed in a region between the condensing optical system 320 and the imaging optical system 330 in the inner region of the main body portion 311. The optical axis of the condensing optical system 320, the optical axis of the imaging optical system 330, and the optical axis of the filter unit 1 (i.e., the center lines of the openings 18 and 23) coincide with the center line of the barrel body 310.

[0095] The condensing optical system 320 and the imaging optical system 330 constitute a non-telecentric optical system. The condensing optical system 320 is an optical system that condenses on-axis incident light and off-axis incident light. The filter unit 1 is disposed at a position where the on-axis incident light and the off-axis incident light intersect in the condensing optical system 320. The filter unit 1 functions as an aperture at this position. The imaging optical system 330 forms an image of the light passing through the filter unit 1 on the image sensor of the hyperspectral camera. Additionally, the condensing optical system 320 and the imaging optical system 330 may also constitute a telecentric optical system.

[0096] The filter unit 1 is fixed to the inside of the main body portion 311 by being clamped between the flange surface 311a provided on the main body portion 311 and the fixing ring 313. The flange surface 311a is an inward flange surface provided on the main body portion 311 so as to face the condensing optical system 320 side. The filter unit 1 is fixed to the inside of the main body portion 311 in a state where the opening 23 is on the condensing optical system 320 side with respect to the Fabry-Perot interference filter 10. As an example, the opening 23 of the filter unit 1 is located at a position where the on-axis incident light and the off-axis incident light of the condensing optical system 320 intersect.

[0097] The connector 5 is disposed within the opening 311b formed in the main body portion 311. The connection port 51 of the connector 5 is exposed to the outside of the cylindrical body 310 via the opening 311b. An adhesive member 77 is disposed between the side surface of the connector 5 and the inner surface of the opening 311b. Thereby, the gap between the side surface of the connector 5 and the inner surface of the opening 311b is sealed.

[0098] [Function and Effect]

[0099] In the filter unit 1, the Fabry - Perot interference filter 10 is disposed within the housing 200, and the wiring substrate 4 is mounted on the housing 200 in such a manner that the entire wiring substrate 4 is buried in the surrounding portion 230 of the housing 200. Thereby, for example, compared with a configuration in which a housing accommodating the Fabry - Perot interference filter 10 is disposed on the wiring substrate, the filter unit 1 can be made thinner in the optical axis direction of the Fabry - Perot interference filter 10 (i.e., the direction in which the pair of mirror portions 14, 15 face each other), that is, the Z - axis direction. In addition, since the wiring substrate 4 is mounted on the housing 200 in such a manner that the entire wiring substrate 4 is buried in the surrounding portion 230 of the housing 200, electrical connection can be performed laterally with respect to the optical axis direction of the Fabry - Perot interference filter 10, that is, the Z - axis direction. Furthermore, since it is not necessary to form wiring in the housing 200, the structure of the housing 200 can be optimized. Therefore, it is suitable for being disposed in a region narrow in the optical axis direction of the Fabry - Perot interference filter 10.

[0100] In the filter unit 1, the housing 200 includes the support body 2 constituting the first wall portion 210 and the surrounding portion 230, and the light - transmitting member 3 constituting the second wall portion 220, and the adhesive members 7 (adhesive members 74, 75) are disposed between the wiring substrate 4 and the support body 2 and between the wiring substrate 4 and the light - transmitting member 3. Thereby, an increase in the thickness in the optical axis direction of the Fabry - Perot interference filter 10, that is, the Z - axis direction, can be suppressed, and a package for accommodating the Fabry - Perot interference filter 10 can be formed by the support body 2, the wiring substrate 4, the light - transmitting member 3, and the adhesive member 7. Thereby, the Fabry - Perot interference filter 10 can be protected from the influence of moisture or fine particles, etc.

[0101] In the filter unit 1, when viewed from the Z - axis direction, the Fabry - Perot interference filter 10 is located at the center C of the support body 2. Thereby, even when an external force acts on the housing 200 laterally with respect to the Z - axis direction, the influence of the external force on the Fabry - Perot interference filter 10 can be suppressed. In addition, for example, by fitting the housing 200 inside the cylindrical body 310 of the lens barrel 300, the Fabry - Perot interference filter 10 can be disposed on the center line of the cylindrical body 310.

[0102] In the filter unit 1, when viewed from the Z-axis direction, the outer edge 200E of the housing 200 has a circular shape. Accordingly, even when an external force is applied to the housing 200 from the side with respect to the Z-axis direction, the external force can be suppressed from reaching the Fabry-Perot interference filter 10 with good balance. Further, for example, when the cylindrical body 310 has a cylindrical shape, the Fabry-Perot interference filter 10 can be easily and accurately arranged on the center line of the cylindrical cylindrical body 310.

[0103] In the filter unit 1, since the housing 200 is a circular plate-shaped member, when the filter unit 1 is arranged in the cylindrical cylindrical body 310, the filter unit 1 can be prevented from rolling in the cylindrical cylindrical body 310.

[0104] In the filter unit 1, the Fabry-Perot interference filter 10 is arranged in the first recess 21. When viewed from the Z-axis direction, the outer edge 10E of the Fabry-Perot interference filter 10 and the inner edge 21E of the first recess 21 are each rectangular. Accordingly, when viewed from the Z-axis direction, since the outer edge 10E of the Fabry-Perot interference filter 10 and the inner edge 21E of the first recess 21 are each rectangular, the positioning of the Fabry-Perot interference filter 10 with respect to the housing 200 can be easily and accurately performed.

[0105] In the filter unit 1, the wiring substrate 4 is mounted on the housing 200 so as not to overlap the Fabry-Perot interference filter 10 when viewed from the Z-axis direction. Accordingly, the filter unit 1 can be made thinner in the optical axis direction of the Fabry-Perot interference filter 10, that is, in the Z-axis direction.

[0106] In the filter unit 1, the Fabry-Perot interference filter 10 and the wiring substrate 4 are arranged on the same plane (the plane in which the bottom surfaces 21a and 22a are located). Accordingly, the filter unit 1 can be made thinner in the optical axis direction of the Fabry-Perot interference filter 10, that is, in the Z-axis direction.

[0107] In the filter unit 1, the second recess 22 in which the wiring substrate 4 is arranged is formed in the surrounding portion 230, and the second recess 22 reaches the outer edge of the surrounding portion 230 when viewed from the Z-axis direction. Accordingly, electrical connection can be performed from the side with respect to the optical axis direction of the Fabry-Perot interference filter 10, that is, in the Z-axis direction, with a simple structure.

[0108] In the filter unit 1, the housing 200 includes a partition portion 26 arranged between the second recess 22 and the first recess 21. Accordingly, by using the partition portion 26 as a reference, the positioning of the Fabry-Perot interference filter 10 and the wiring substrate 4 with respect to the housing 200 can be easily and accurately performed.

[0109] In the filter unit 1, when viewed from the Z-axis direction, the distance D1 in the Y-axis direction "from the inner edge 21E of the first recess 21 to the outer edge 2E of the support 2 (i.e., the outer edge of the surrounding portion 230)" is greater than the width Wf of the Fabry-Perot interference filter 10 in the Y-axis direction. Thus, even if an external force is applied to the housing 200 from the side with respect to the Z-axis direction, it is possible to suppress the spread of this external force to the Fabry-Perot interference filter 10.

[0110] In the filter unit 1, the distance D2 in the Y-axis direction "from the outer edge 10E of the Fabry-Perot interference filter 10 to the outer edge 2E of the support 2" is greater than the length L of the diagonal of the outer edge 10E of the Fabry-Perot interference filter 10, and when viewed from the Z-axis direction, the width W3 of the opening 23 is smaller than the width Wf of the Fabry-Perot interference filter 10 in the Y-axis direction. Thus, when viewed from the Z-axis direction, the opening 23 becomes very small compared to the support 2, so it is possible to suppress stray light from entering the Fabry-Perot interference filter 10.

[0111] In the above-mentioned lens barrel 300, the filter unit 1 serves as an aperture between the condenser optical system 320 and the imaging optical system 330. Thus, it is possible to deepen the depth of field in the hyperspectral camera equipped with the lens barrel 300.

[0112] In the filter unit 1, regarding the width Wf of the Fabry-Perot interference filter 10 in the Y-axis direction, the width Ws of the wiring substrate 4 in the Y-axis direction, the width W1 of the first recess 21 in the Y-axis direction, and the width W2 of the second recess 22 in the Y-axis direction, the relationship "Wf ≤ W1 < Ws ≤ W2" holds. Thus, since the width W1 of the first recess 21 and the width W2 of the second recess 22 are different from each other, it is possible to easily and accurately perform the positioning of the Fabry-Perot interference filter 10 and the wiring substrate 4 with respect to the support 2 with the boundary portion between the first recess 21 and the second recess 22 as a reference (e.g., a mechanical positioning portion or a reference coordinate). In addition, compared with the case where the width W1 of the first recess 21 is adjusted to be the same as the width W2 of the second recess 22, the strength of the support 2 can be ensured. Further, even if an external force is applied to the wiring substrate 4 from the side with respect to the Z-axis direction, this external force can be released from the boundary portion between the first recess 21 and the second recess 22 to the support 2, and it is possible to suppress the spread of this external force to the Fabry-Perot interference filter 10.

[0113] In the filter unit 1, regarding the width Wf of the Fabry-Perot interference filter 10 in the Y-axis direction and the width W1 of the first recess 21 in the Y-axis direction, the relationship "Wf = W1" holds. Thus, it is possible to more easily and with higher accuracy perform the positioning of the Fabry-Perot interference filter 10 with respect to the housing 200.

[0114] In the filter unit 1, with respect to the width Ws of the wiring substrate 4 in the Y-axis direction and the width W2 of the second recess 22 in the Y-axis direction, the relationship "Ws = W2" holds. Thus, the positioning of the wiring substrate 4 with respect to the housing 200 can be performed more easily and with higher precision.

[0115] In the filter unit 1, a through hole 24 is formed in the housing 200 and opens at the bottom surface 21a of the first recess 21 which is the inner surface of the housing 200 and the surface 2b of the support 2 which is the outer surface of the housing 200. Thus, when manufacturing the filter unit 1, even if gas is generated in the space inside the housing 200, the gas can be released to the outside through the through hole 24.

[0116] [Modification Example]

[0117] The present disclosure is not limited to the above-described embodiments. For example, with respect to the width Wf of the Fabry - Perot interference filter 10 in the Y-axis direction, the width Ws of the wiring substrate 4 in the Y-axis direction, the width W1 of the first recess 21 in the Y-axis direction, and the width W2 of the second recess 22 in the Y-axis direction, when the relationship "Wf ≤ W1 < Ws ≤ W2" holds ( Figure 5 the case shown), the relationship "Wf < W1" may also hold. Similarly, when the relationship "Wf ≤ W1 < Ws ≤ W2" holds ( Figure 5 the case shown), the relationship "Ws < W2" may also hold.

[0118] In addition, as Figure 9 shown, with respect to the width Wf of the Fabry - Perot interference filter 10 in the Y-axis direction, the width Ws of the wiring substrate 4 in the Y-axis direction, the width W1 of the first recess 21 in the Y-axis direction, and the width W2 of the second recess 22 in the Y-axis direction, the relationship "Ws ≤ W2 < Wf ≤ W1" may also hold. In this case, the positioning of the Fabry - Perot interference filter 10 and the wiring substrate 4 with respect to the support 2 can also be performed easily and with good precision. In addition, compared with the case where the width W2 of the second recess 22 is adjusted to be the same as the width W1 of the first recess 21, the strength of the support 2 can be ensured. In addition, stray light incident on the Fabry - Perot interference filter 10 via the second recess 22 in which the wiring substrate 4 is disposed can be suppressed. Moreover, compared with the case where the width W2 of the second recess 22 is adjusted to be the same as the width W1 of the first recess 21, the portions on both sides of the second recess 22 in the Y-axis direction in the support 2 are closer to the wiring substrate 4, so the heat generated in the wiring substrate 4 can be efficiently released to the support 2.

[0119] In addition, the widened portion 25 only needs to be widened at least in the Y-axis direction with respect to the opening of the first recess 21. As an example, as Figure 9As shown, the widened portion 25 may also extend from the opening of the first concave portion 21 to the opening of the second concave portion 22, and widen at least in the Y-axis direction with respect to the openings of the first concave portion 21 and the second concave portion 22. This applies not only to the case where the relationship of "Ws ≤ W2 < Wf ≤ W1" holds ( Figure 9 the case shown), but also to the case where the relationship of "Wf ≤ W1 < Ws ≤ W2" holds ( Figure 5 the case shown). If the widened portion 25 extends from the opening of the first concave portion 21 to the opening of the second concave portion 22, an increase in the thickness in the optical axis direction of the Fabry - Perot interference filter 10, i.e., the Z-axis direction, can be suppressed, and the light transmissive member 3 can be more stably supported on the support 2.

[0120] In addition, as Figure 10 (a) and (b) shown, the filter unit 1 may also include a flexible wiring substrate 9 in order to connect to wiring externally. In Figure 10 the example of the lens barrel shown in (a), one end of the flexible wiring substrate 9 is connected to the wiring substrate 4, and the connector 5 connected to the other end of the flexible wiring substrate 9 is disposed within the opening 311b of the cylinder 310. In this case, an adhesive member 77 is disposed between the side surface of the connector 5 and the inner surface of the opening 311b. In Figure 10 the example of the lens barrel shown in (b), one end of the flexible wiring substrate 9 is connected to the wiring substrate 4, and the other end of the flexible wiring substrate 9 is led out to the outside through the opening 311b of the cylinder 310. In this case, an adhesive member 77 is disposed between the flexible wiring substrate 9 and the inner surface of the opening 311b.

[0121] In addition, the filter unit 1 may also include a Fabry - Perot interference filter as Figure 11 shown. The Fabry - Perot interference filter 400 shown in Figure 11 will be described. The Fabry - Perot interference filter 400 includes a substrate layer 411, a mirror portion 412, and a drive electrode 413. The substrate layer 411 has surfaces 411a and 411b facing each other. The substrate layer 411 is formed of a light - transmissive material. The mirror portion 412 is, for example, a metal film, a dielectric multilayer film, or a composite film thereof. The drive electrode 413 is formed of a metal material, for example.

[0122] The Fabry - Perot interference filter 400 further includes a substrate layer 421, a mirror portion 422, and a drive electrode 423. The substrate layer 421 has surfaces 421a and 421b facing each other. The substrate layer 421 is formed of a light - transmissive material. The mirror portion 422 is, for example, a metal film, a dielectric multilayer film, or a composite film thereof. The drive electrode 423 is formed of a metal material, for example.

[0123] A recess 414 is formed on the surface 411a of the substrate layer 411. A convex portion 415 is provided on the bottom surface 414a of the recess 414. When taking the bottom surface 414a as a reference, the height of the end surface 415a of the convex portion 415 is lower than the height of the surface 411a of the substrate layer 411. The mirror portion 412 is provided on the end surface 415a of the convex portion 415. The drive electrode 413 is provided on the bottom surface 414a of the recess 414 so as to surround the convex portion 415. The drive electrode 413 is electrically connected to an electrode pad (not shown) via a wiring (not shown) provided in the substrate layer 411, for example. This electrode pad is provided in an area of the substrate layer 411 that can be accessed from the outside, for example.

[0124] The surface 421b of the substrate layer 421 is joined to the surface 411a of the substrate layer 411 by plasma bonding or the like, for example. A mirror portion 422 and a drive electrode 423 are provided on the surface 421b of the substrate layer 421. The mirror portion 422 faces the mirror portion 412 with a gap S therebetween. The drive electrode 423 is provided on the surface 421b of the substrate layer 421 so as to surround the mirror portion 422 and faces the drive electrode 413 with a gap S therebetween. The drive electrode 423 is electrically connected to an electrode pad (not shown) via a wiring (not shown) provided in the substrate layer 421, for example. This electrode pad is provided in an area of the substrate layer 421 that can be accessed from the outside, for example.

[0125] On the surface 421a of the substrate layer 421, a groove 424 is formed so as to surround the mirror portion 422 and the drive electrode 423 when viewed from the Z-axis direction. The groove 424 extends in an annular shape. The portion of the substrate layer 421 surrounded by the groove 424 forms a diaphragm-like holding portion 425 with the portion where the groove 424 is formed and can move in the direction in which the pair of mirror portions 412 and 422 face each other.

[0126] In addition, the diaphragm-like holding portion 425 may also be constituted by a groove formed on at least one of the surface 421a and the surface 421b of the substrate layer 421 so as to surround the mirror portion 422 and the drive electrode 423 when viewed from the Z-axis direction. A groove that surrounds the mirror portion 412 and the drive electrode 413 when viewed from the Z-axis direction may also be formed in the substrate layer 411, thereby forming a diaphragm-like holding portion in the substrate layer 411. Instead of the diaphragm-like holding portion, the holding portion may be constituted by a plurality of beams arranged radially.

[0127] In Figure 11In the Fabry - Perot interference filter 400 shown, if a potential difference is generated between the drive electrode 413 and the drive electrode 423 by applying a voltage to the drive electrode 413 and the drive electrode 423, an electrostatic force corresponding to the potential difference is generated between the drive electrode 413 and the drive electrode 423. By generating an electrostatic force between the drive electrode 413 and the drive electrode 423, the portion of the substrate layer 421 surrounded by the groove 424 is attracted to the substrate layer 411 side, and the distance between the mirror portion 412 and the mirror portion 422 is adjusted. Thereby, light having a wavelength corresponding to the distance between the mirror portion 412 and the mirror portion 422 passes through.

[0128] In addition, in the filter unit 1, when viewed from the Z - axis direction, the outer edge 2E of the support 2 may have a shape other than a circular shape such as a rectangular shape. In the filter unit 1, the outer edge 10E of the Fabry - Perot interference filter 10, the outer edge 4E of the wiring substrate 4, the inner edge 21E of the first recess 21, and the inner edge 22E of the second recess 22 may each have a shape other than a rectangular shape.

[0129] In the filter unit 1, when viewed from the Z - axis direction, the Fabry - Perot interference filter 10 may be offset from the center C of the support 2. In the filter unit 1, the mounting surface of the support 2 on which the Fabry - Perot interference filter 10 is disposed may not be the bottom surface 21a of the first recess 21. In the filter unit 1, the mounting surface of the support 2 on which the wiring substrate 4 is disposed may not be the bottom surface 22a of the second recess 22. In the filter unit 1, the mounting surface of the support 2 on which the Fabry - Perot interference filter 10 is disposed and the mounting surface of the support 2 on which the wiring substrate 4 is disposed may not be in the same plane.

[0130] In the filter unit 1, the entire Fabry - Perot interference filter 10 may not be disposed within the first recess 21. In the filter unit 1, the entire light - transmitting member 3 may not be disposed within the widening portion 25. In the filter unit 1, the entire wiring substrate 4 may not be disposed within the second recess 22. In the filter unit 1, the wiring substrate 4 may be mounted on the housing 200 in such a manner that a part of the wiring substrate 4 is buried in the surrounding portion 230. In addition, "a part of the wiring substrate 4 is buried in the surrounding portion 230" means that, when viewed from any one of the X - axis direction, the Y - axis direction, and the Z - axis direction, this part of the wiring substrate 4 overlaps with the surrounding portion 230.

[0131] In the filter unit 1, the support 2 may also not include the partition 26 disposed between the first recess 21 and the second recess 22. In the filter unit 1, the first recess 21 and the second recess 22 may also be connected to each other. When the support 2 includes the partition 26, the partition 26 may not completely separate the first recess 21 and the second recess 22, but may partially separate them. When the support 2 includes the partition 26, the height of the partition 26 in the Z-axis direction is not limited to the above height. For example, the height of the partition 26 in the Z-axis direction may be higher than the height of the Fabry-Perot interference filter 10 in the Z-axis direction based on the bottom surface 21a of the first recess 21. The height of the partition 26 in the Z-axis direction may also be higher than the height of the wiring substrate 4 in the Z-axis direction based on the bottom surface 22a of the second recess 22. The partition 26 may be formed separately from the support 2 and may be mounted on the support 2.

[0132] In the filter unit 1, when viewed from the Z-axis direction, the "distance from the inner edge 21E of the first recess 21 to the outer edge 2E of the support 2" in a direction other than the Y-axis direction may also be greater than the width of the Fabry-Perot interference filter 10 in this direction. In the filter unit 1, the "distance from the outer edge 10E of the Fabry-Perot interference filter 10 to the outer edge 2E of the support 2" in the "direction perpendicular to one side of the outer edge 10E of the Fabry-Perot interference filter 10" other than the Y-axis direction may also be greater than the diagonal length of the outer edge 10E of the Fabry-Perot interference filter 10. When viewed from the Z-axis direction, the width of the opening 23 may also be smaller than the width of the Fabry-Perot interference filter 10 in the direction perpendicular to this side.

[0133] In the filter unit 1, the opening 23 is formed as a light passage portion in the support 2. However, for example, the area within the opening 23 may be filled with a light-transmissive material, or an optical element (such as a lens, a filter, etc.) may be disposed within the opening 23. In any case, the light passage portion can allow the light emitted from the Fabry-Perot interference filter 10 (or the Fabry-Perot interference filter 400) to pass through, or can also allow the light incident on the Fabry-Perot interference filter 10 (or the Fabry-Perot interference filter 400) to pass through. In the filter unit 1, the through hole 24 only needs to open on the inner surface of the first recess 21 and the outer surface of the support 2. In the filter unit 1, the cover 6 may not be disposed on the surface 2b of the support 2. In the filter unit 1, an anti-light reflection film may be formed on at least one of the surface 2b of the support 2 and the inner surface of the opening 23. As an example, when the support 2 is formed of stainless steel, the anti-light reflection film may be formed by performing a chromium plating treatment on the surface of the support 2.

[0134] In the filter unit 1, the wiring substrate 4 may also be mounted on the housing 200 such that a part of the wiring substrate 4 is located in the through-hole formed in the surrounding portion 230. In this case, a part of the wiring substrate 4 located in the through-hole of the surrounding portion 230 is in a state of being embedded in the surrounding portion 230.

Claims

1. A filter unit, wherein, it comprises: a housing including a first wall portion having a light passing portion, a second wall portion opposite to the first wall portion, and an enclosing portion surrounding the region between the first wall portion and the second wall portion; a Fabry - Perot interference filter including a pair of mirror portions facing each other in a first direction and having a variable distance therebetween, and disposed in the housing so as to overlap the light passing portion when viewed from the first direction; a wiring substrate mounted on the housing in such a manner that at least a part thereof is embedded in the enclosing portion and electrically connected to the Fabry - Perot interference filter; and an adhesive member disposed between the wiring substrate and the housing.

2. The filter unit according to claim 1, wherein, the housing includes a support body constituting the first wall portion and the enclosing portion and a light transmissive member constituting the second wall portion, the adhesive member is disposed between the wiring substrate and the support body and between the wiring substrate and the light transmissive member.

3. The filter unit according to claim 1 or 2, wherein, when viewed from the first direction, the Fabry - Perot interference filter is located at the center of the housing.

4. The filter unit according to claim 3, wherein, when viewed from the first direction, the outer edge of the housing is circular.

5. The filter unit according to any one of claims 1 to 4, wherein, a first recess is defined by the first wall portion and the enclosing portion, the Fabry - Perot interference filter is disposed in the first recess, when viewed from the first direction, the outer edge of the Fabry - Perot interference filter and the inner edge of the first recess are each rectangular.

6. The filter unit according to any one of claims 1 to 5, wherein, the wiring substrate is mounted on the housing so as not to overlap the Fabry - Perot interference filter when viewed from the first direction.

7. The filter unit according to claim 6, wherein, the Fabry - Perot interference filter is disposed on a first mounting surface of the first wall portion, the wiring substrate is disposed on a second mounting surface of the enclosing portion, the first mounting surface and the second mounting surface are in the same plane.

8. The filter unit according to any one of claims 1 to 7, wherein, a second recess is formed in the enclosing portion, the second recess having the first direction as the depth direction and opening on the side of the second wall portion, the second recess reaches the outer edge of the enclosing portion when viewed from the first direction, the wiring substrate is disposed in the second recess.

9. The filter unit according to any one of claims 1 to 8, wherein, a first recess is defined by the first wall portion and the enclosing portion, a second recess is formed in the enclosing portion, the second recess having the first direction as the depth direction and opening on the side of the second wall portion, the Fabry - Perot interference filter is disposed in the first recess, the wiring substrate is disposed in the second recess, the housing further includes a partition portion disposed between the first recess and the second recess.

10. The filter unit according to any one of claims 1 to 9, wherein a first concave portion is defined by the first wall portion and the surrounding portion, the Fabry - Perot interference filter is disposed within the first concave portion, when viewed from the first direction, the distance from the inner edge of the first concave portion to the outer edge of the surrounding portion in one direction is greater than the width of the Fabry - Perot interference filter in the one direction.

11. The filter unit according to any one of claims 1 to 10, wherein a first concave portion is defined by the first wall portion and the surrounding portion, the Fabry - Perot interference filter is disposed within the first concave portion, the light passing portion is an opening formed in the first wall portion, when viewed from the first direction, the outer edge of the Fabry - Perot interference filter is rectangular, when viewed from the first direction, the distance from the outer edge of the Fabry - Perot interference filter to the outer edge of the surrounding portion in a direction perpendicular to one side of the outer edge of the Fabry - Perot interference filter is greater than the length of the diagonal of the outer edge of the Fabry - Perot interference filter, when viewed from the first direction, the width of the opening is less than the width of the Fabry - Perot interference filter in the direction perpendicular to the one side.

12. The filter unit according to any one of claims 1 to 11, wherein a first concave portion is defined by the first wall portion and the surrounding portion, a second concave portion is formed in the surrounding portion, the second concave portion has the first direction as the depth direction and opens on the side of the second wall portion, the first concave portion and the second concave portion are arranged in a second direction perpendicular to the first direction, the Fabry - Perot interference filter is disposed within the first concave portion, the wiring substrate is disposed within the second concave portion, if the width of the Fabry - Perot interference filter in a third direction perpendicular to both the first direction and the second direction is set as Wf, the width of the wiring substrate in the third direction is set as Ws, the width of the first concave portion in the third direction is set as W1, and the width of the second concave portion in the third direction is set as W2, then the relationship of "Wf ≤ W1 < Ws ≤ W2" or the relationship of "Ws ≤ W2 < Wf ≤ W1" holds.

13. The filter unit according to claim 12, wherein the relationship of "Wf = W1" holds.

14. The filter unit according to claim 12 or 13, wherein the relationship of "Ws = W2" holds.

15. The filter unit according to any one of claims 1 to 14, wherein a through - hole that opens on the inner surface and the outer surface of the housing is formed in the housing.

Images