filter unit

Abstract

To provide a filter unit that is suitable for the arrangement of a Fabry-Perot interference filter in an area narrow in an optical axis direction.SOLUTION: A filter unit 1 comprises: a housing 200 that includes a first wall part 210 having an opening 23, a second wall part 220 facing the first wall part 210, and a surrounding part 230 surrounding an area between the first wall part 210 and the second wall part 220; a Fabry-Perot interference filter 10 that includes a pair of mirror parts facing each other in a Z-axis direction, the distance between which is variable, and is arranged inside the housing 200 to overlap the opening 23 when seen from the Z-axis direction; a wiring board 4 that is attached to the housing 200 to be at least partially embedded in the surrounding part 230, and is electrically connected with the Fabry-Perot interference filter 10; and an adhesive member 7 that is arranged between the wiring board 4 and the housing 200.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention 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 parts with variable distance from each other, the following structure can be considered. That is, a structure including a wiring board, a housing arranged on the wiring board, a Fabry - Perot interference filter arranged in the housing, a terminal spanned between the wiring board and a side wall part of the housing, and a wire spanned between the Fabry - Perot interference filter and the terminal (for example, refer to Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the filter unit to which the above - described structure is applied, it is difficult to make the filter unit thin in the optical axis direction of the Fabry - Perot interference filter (that is, the direction in which the pair of mirror parts face each other), and 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 problem that it is not suitable for arrangement in a narrow region in the optical axis direction of the Fabry - Perot interference filter (for example, the region between lenses in a lens barrel).

[0005] An object of the present invention is to provide a filter unit suitable for arrangement in a narrow region in the optical axis direction of a Fabry - Perot interference filter.

Means for Solving the Problems

[0006] The filter unit of the present invention may also be [1] a filter unit comprising: a housing including a first wall portion having a light-transmitting portion, a second wall portion facing the first wall portion, and a surrounding 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 between them, and disposed within the housing so as to overlap with the light-transmitting portion when viewed from the first direction; a wiring board attached to the housing such that at least a portion of it is embedded in the surrounding portion and electrically connected to the Fabry-Perot interference filter; and an adhesive member disposed between the wiring board and the housing.

[0007] In the filter unit described in [1] above, the Fabry-Perot interference filter is housed within the housing, and the wiring board is mounted to the housing such that at least a portion of the wiring board is embedded in the surrounding portion of the housing. This makes the filter unit 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 mirrors face each other), compared to, for example, a configuration in which the housing containing the Fabry-Perot interference filter is placed on the wiring board. Furthermore, because the wiring board is mounted to the housing such that at least a portion of the wiring board is embedded in the surrounding portion of the housing, electrical connections can be made from the side in the first direction, which is the optical axis direction of the Fabry-Perot interference filter. In addition, since it is not necessary to form wiring in the housing, the configuration of the housing can be optimized. Therefore, the filter unit described in [1] above is suitable for placement in a narrow area in the optical axis direction of the Fabry-Perot interference filter.

[0008] The filter unit of the present invention may also be [2] "the filter unit according to [1] above, wherein the housing includes a support that constitutes the first wall portion and the surrounding portion, and a light-transmitting member that constitutes the second wall portion, and the adhesive member is disposed between the wiring board and the support, and between the wiring board and the light-transmitting member." According to the filter unit according to [2], a package for housing the Fabry-Perot interference filter can be constructed using the support, wiring board, light-transmitting member and adhesive member, while suppressing an increase in thickness in the first direction which is the optical axis direction of the Fabry-Perot interference filter. This makes it possible to protect the Fabry-Perot interference filter from moisture, particles, etc.

[0009] The filter unit of the present invention may also be [3] "the filter unit according to [1] or [2] above, 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 according to [3], even if an external force acts on the housing from the side with respect to the first direction, it is possible to suppress the effect of such external force on the Fabry-Perot interference filter. Furthermore, for example, by fitting the housing inside a cylindrical body such as a lens barrel, the Fabry-Perot interference filter can be positioned on the centerline of the cylindrical body.

[0010] The filter unit of the present invention may also be [4] "the filter unit described in [3] above, wherein, when viewed from the first direction, the outer edge of the housing is circular in shape." According to the filter unit described in [4], even if an external force acts on the housing from the side with respect to the first direction, it is possible to suppress the effect of such external force on the Fabry-Perot interference filter in a balanced manner. Furthermore, for example, if the cylindrical body is cylindrical, the Fabry-Perot interference filter can be easily and accurately positioned on the center line of the cylindrical body.

[0011] The filter unit of the present invention 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 rectangular in shape." According to the filter unit according to [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 rectangular in shape, so that the Fabry-Perot interference filter can be positioned relative to the housing easily and accurately.

[0012] The filter unit of the present invention may also be [6] "the filter unit according to any one of [1] to [5] above, wherein the wiring board is mounted on the housing such that it does not overlap with the Fabry-Perot interference filter when viewed from the first direction." According to the filter unit according to [6], the filter unit can be made thinner in the first direction, which is the optical axis direction of the Fabry-Perot interference filter.

[0013] The filter unit of the present invention may also be [7] "the filter unit according to [6] above, wherein the Fabry-Perot interference filter is arranged on a first mounting surface of the first wall portion, the wiring board is arranged on a second mounting surface of the surrounding portion, and the first mounting surface and the second mounting surface are located on the same plane." According to the filter unit according to [7], the filter unit can be made thinner in the first direction which is the optical axis direction of the Fabry-Perot interference filter.

[0014] The filter unit of the present invention may also be [8] "the filter unit according to any one of [1] to [7] above, wherein the surrounding portion has a second recess formed therein that opens toward the second wall portion with the first direction as the depth direction, the second recess reaches the outer edge of the surrounding portion when viewed from the first direction, and the wiring board is arranged in the second recess." According to the filter unit according to [8], electrical connection can be made from the side with respect to the first direction, which is the optical axis direction of the Fabry-Perot interference filter, with a simple configuration.

[0015] The filter unit of the present invention may also be [9] "a 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 which opens toward the second wall portion with the first direction as the depth direction, the Fabry-Perot interference filter is disposed in the first recess, the wiring board 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 according to [9], the Fabry-Perot interference filter and the wiring board can be positioned relative to the housing with ease and accuracy by using the partition portion as a reference.

[0016] The filter unit of the present invention may also be

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

[10] , even if an external force acts on the housing from the side with respect to the first direction, it is possible to suppress the external force from affecting the Fabry-Perot interference filter.

[0017] The filter unit of the present invention may also be

[11] "a filter unit according to any one of [1] to

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

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

[0018] The filter unit of the present invention is "

[12] A first recess is defined by the first wall portion and the surrounding portion, and a second recess that opens toward the second wall portion with the first direction as the depth direction is formed in the surrounding portion. The first recess and the second recess are arranged side by side in a second direction perpendicular to the first direction. The Fabry - Perot interference filter is arranged in the first recess, and the wiring board is arranged in the second recess. When the width of the Fabry - Perot interference filter in a third direction perpendicular to both the first direction and the second direction is Wf, the width of the wiring board in the third direction is Ws, the width of the first recess in the third direction is W1, and the width of the second recess in the third direction is W2, the relationship of "Wf≤W1<Ws≤W2" or the relationship of "Ws≤W2<Wf≤W1" holds, and it may be the filter unit according to any one of the above [1] to

[11] ". According to the filter unit described in

[12] , since the width W1 of the first recess and the width W2 of the second recess are different from each other, by using the boundary between the first recess and the second recess as a reference (for example, a mechanical positioning portion or a reference coordinate), the positioning of the Fabry - Perot interference filter and the wiring board with respect to the housing can be easily and accurately performed. Also, compared with the case where the smaller width is combined with the larger width of the width W1 of the first recess and the width W2 of the second recess, 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 board from the side with respect to the first direction, the external force can be released from the boundary between the first recess and the second recess to the support, and the influence of the external force on the Fabry - Perot interference filter can be suppressed. On the other hand, when the relationship of "Ws≤W2<Wf≤W1" holds, stray light incident on the Fabry - Perot interference filter can be suppressed through the second recess in which the wiring board is arranged.

[0019] The filter unit of the present invention may be "

[13] The filter unit according to the above

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

[13] , the positioning of the Fabry - Perot interference filter with respect to the housing can be performed more easily and more accurately.

[0020] The filter unit of the present invention may be the filter unit described in

[14] "the filter unit described in

[12] or

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

[14] , the positioning of the wiring board with respect to the housing can be performed more easily and with higher accuracy.

[0021] The filter unit of the present invention may be the filter unit described in

[15] "the filter unit described in any one of [1] to

[14] where through holes that open to the inner surface and the outer surface of the housing are formed in the housing". According to the filter unit described in

[15] , for example, even if gas is generated in the space inside the housing during the manufacture of the filter unit, the gas can be released to the outside through the through holes.

Effect of the Invention

[0022] According to the present invention, it is possible to provide a filter unit suitable for arranging in a narrow region in the optical axis direction of a Fabry - Perot interference filter.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view of a Fabry - Perot interference filter included in a filter unit of an embodiment. [Figure 2] It is a cross - sectional view of the Fabry - Perot interference filter along the line II - II shown in FIG. 1. [Figure 3] It is a plan view of a filter unit of an embodiment. [Figure 4] It is a cross - sectional view of the filter unit along the line IV - IV shown in FIG. 3. [Figure 5] It is a plan view of a part of a filter unit of an embodiment. [Figure 6] It is a plan view of a part of a filter unit of an embodiment. [Figure 7] It is a bottom view of a filter unit of an embodiment. [Figure 8]This is a cross-sectional view of a lens barrel equipped with a filter unit according to one embodiment. [Figure 9] This is a plan view of a portion of the modified filter unit. [Figure 10] This is a cross-sectional view of a portion of the lens barrel equipped with a modified filter unit. [Figure 11] This is a cross-sectional view of a modified Fabry-Perot interference filter. [Modes for carrying out the invention]

[0024] Embodiments of the present invention will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations are omitted. [Configuration of the Fabry-Perot interference filter included in the filter unit]

[0025] As shown in Figure 1, the Fabry-Perot interference filter 10 has a light-transmitting 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-transmitting region 10a is a cylindrical region with a center line parallel to the Z-axis direction. When viewed from the Z-axis direction, the center of the light-transmitting region 10a coincides with the center of the Fabry-Perot interference filter 10.

[0026] As shown in Figure 2, the Fabry-Perot interference filter 10 comprises a substrate 11 with the Z-axis direction as the thickness direction. The material of the substrate 11 is, for example, silicon, quartz, or glass. The substrate 11 has a pair of surfaces 11a and 11b. The pair of surfaces 11a and 11b face each other in the Z-axis direction. A first laminated structure 12 is laminated on surface 11a of the substrate 11. A second laminated structure 13 is laminated on surface 11b of the substrate 11.

[0027] The first laminated structure 12 includes an anti-reflective layer 121, a first laminate 122, an intermediate layer 123, and a second laminate 124. The anti-reflective layer 121, the first laminate 122, the intermediate layer 123, and the second laminate 124 are laminated on the surface 11a of the substrate 11 in this order. An air gap S is formed between the first laminate 122 and the second laminate 124 by the frame-shaped intermediate layer 123. When the material of the substrate 11 is silicon, the materials of the anti-reflective layer 121 and the intermediate layer 123 are, for example, silicon oxide. The thickness of the intermediate layer 123 is, for example, an integer multiple of half the design center wavelength. The thickness of the intermediate layer 123 may be greater than an integer multiple of half the design center wavelength if necessary.

[0028] The portion of the first laminate 122 corresponding to the light-transmitting region 10a functions as a mirror portion 14. The mirror portion 14 is supported by the substrate 11 via an anti-reflective layer 121. As an example, the first laminate 122 is composed of multiple polysilicon layers and multiple silicon nitride layers stacked alternately one layer at a time. The optical thickness of each layer constituting the mirror portion 14 is, for example, an integer multiple of 1 / 4 of the design center wavelength. Note that silicon oxide layers may be used instead of silicon nitride layers.

[0029] The portion of the second laminate 124 corresponding to the light-transmitting region 10a functions as a mirror portion 15. The mirror portion 15 is supported on the substrate 11 via an anti-reflective layer 121, the first laminate 122, and an intermediate layer 123, and faces the mirror portion 14 through a gap S. As an example, the second laminate 124 is composed of multiple polysilicon layers and multiple silicon nitride layers stacked alternately one layer at a time. The optical thickness of each layer constituting the mirror portion 15 is, for example, an integer multiple of 1 / 4 of the design center wavelength. Note that a silicon oxide layer may be used instead of a silicon nitride layer. Note that multiple through holes are formed in the portion of the second laminate 124 corresponding to the gap S, to the extent that they do not substantially affect the function of the mirror portion 15. The multiple through holes were used when forming the gap S by removing a part of the intermediate layer 123 by etching.

[0030] The mirror portion 14 has a first electrode 125 and a second electrode 126 formed thereon. The first electrode 125 surrounds the light-transmitting region 10a when viewed from the Z-axis direction. The second electrode 126 overlaps with the light-transmitting region 10a when viewed from the Z-axis direction. The shape of the second electrode 126 when viewed from the Z-axis direction is substantially the same as the shape of the light-transmitting region 10a when viewed from the Z-axis direction. Both the first electrode 125 and the second electrode 126 are formed by doping a portion of the polysilicon layer with impurities to reduce the resistance of that portion.

[0031] A third electrode 127 is formed on the mirror portion 15. The third electrode 127 faces the first electrode 125 and the second electrode 126 with an air gap S between them. The third electrode 127 is formed by doping a portion of the polysilicon layer with impurities to reduce the resistance of that portion. For example, the distance between the second electrode 126 and the third electrode 127 is approximately the same as the distance between the first electrode 125 and the third electrode 127.

[0032] The first laminated structure 12 is provided with a pair of terminals 16 flanking the light-transmitting region 10a (see Figure 1). Each terminal 16 is located within a through-hole formed in the second laminated structure 124 and the intermediate layer 123, opening on the side opposite to the substrate 11 and extending to the first laminated structure 122. Each terminal 16 is electrically connected to the first electrode 125 via wiring 125a.

[0033] The first laminated structure 12 is provided with a pair of terminals 17 flanking the light-transmitting region 10a (see Figure 1). Each terminal 17 is positioned within a through-hole formed in the second laminated structure 124 and the intermediate layer 123, opening on the side opposite to the substrate 11 and extending to the intermediate layer 123. Each terminal 17 is electrically connected to the second electrode 126 via wiring 126a and to the third electrode 127 via wiring 127a. The direction in which the pair of terminals 17 flanks the light-transmitting region 10a is perpendicular to the direction in which the pair of terminals 16 flanks the light-transmitting region 10a (see Figure 1).

[0034] A pair of trenches 122a are formed in the first laminate 122. Each trench 122a extends in an annular shape so as to surround the portion of the wiring 126a that extends in the Z-axis direction from each terminal 17. Each trench 122a electrically insulates the first electrode 125 from the wiring 126a. A trench 122b is formed in the first laminate 122. The trench 122b extends in an annular shape along the inner edge of the first electrode 125. The trench 122b electrically insulates the first electrode 125 from the second electrode 126. The areas within each trench 122a,122b may be filled with insulating material or may be voids.

[0035] A pair of trenches 124a are formed in the second laminate 124. Each trench 124a extends in an annular shape so as to surround each terminal 16. Each trench 124a electrically insulates each terminal 16 from the third electrode 127. The area within each trench 124a may be filled with insulating material or may be an empty space.

[0036] The second laminated structure 13 includes an anti-reflective layer 131, a third laminated body 132, an intermediate layer 133, and a fourth laminated body 134. The anti-reflective layer 131, the third laminated body 132, the intermediate layer 133, and the fourth laminated body 134 are laminated on the surface 11b of the substrate 11 in this order. The anti-reflective layer 131 and the intermediate layer 133 have the same configuration as the anti-reflective layer 121 and the intermediate layer 123, respectively. The third laminated body 132 and the fourth laminated body 134 have a laminated structure that is symmetrical to the first laminated body 122 and the second laminated body 124 with respect to the substrate 11, respectively. The anti-reflective layer 131, the third laminated body 132, the intermediate layer 133, and the fourth laminated body 134 have the function of suppressing warping of the substrate 11.

[0037] The third laminate 132, the intermediate layer 133, and the fourth laminate 134 have openings 18 that include the light-transmitting region 10a. The openings 18 overlap with the light-transmitting region 10a when viewed from the Z-axis direction. The shape of the openings 18 when viewed from the Z-axis direction is substantially the same as the shape of the light-transmitting region 10a when viewed from the Z-axis direction. In other words, the center line of the openings 18 coincides with the center line of the light-transmitting region 10a. The openings 18 open on the side opposite to the substrate 11 and extend to the anti-reflective layer 131.

[0038] A light-shielding layer 135 is formed on the surface of the fourth laminate 134 opposite to the substrate 11. The material of the light-shielding layer 135 is, for example, aluminum. A protective layer 136 is formed on the surface of the light-shielding layer 135 and on the inner surface of the opening 18. The material of the protective layer 136 is, for example, aluminum oxide. By making the thickness of the protective layer 136 100 nm or less (preferably about 30 nm), the optical influence of the protective layer 136 can be ignored.

[0039] In the Fabry-Perot interference filter 10 configured as described above, when a voltage is applied to the first electrode 125 and the third electrode 127 via multiple terminals 16 and 17, a potential difference is generated between the first electrode 125 and the third electrode 127, and an electrostatic force corresponding to this potential difference is generated between the first electrode 125 and the third electrode 127. The electrostatic force generated between the first electrode 125 and the third electrode 127 attracts the mirror portion 15 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, which is at the same potential as the third electrode 127, functions as a compensating electrode, and the mirror portion 15 is kept flat in the light transmission region 10a.

[0040] Thus, in the Fabry-Perot interference filter 10, a pair of mirror sections 14 and 15 facing each other in the Z-axis direction function as a pair of mirror sections whose distance from each other is variable. Here, the wavelength of light transmitted through the Fabry-Perot interference filter 10 depends on the distance between mirror section 14 and mirror section 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 light transmitted through the Fabry-Perot interference filter 10 can be selected. [Configuration of the filter unit]

[0041] As shown in Figures 3 and 4, the filter unit 1 comprises a support 2, a light-transmitting member 3, a wiring board 4, a connector 5, a cover 6, and the Fabry-Perot interference filter 10 described above. In Figure 3, the light-transmitting member 3 and the adhesive members 73 and 75, which will be described later, are shown by dashed lines.

[0042] The support 2 is a circular plate-shaped member with the Z-axis direction (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 surface 2a and the outer edge of 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.

[0043] As shown in Figures 4 and 5, the support 2 has a first recess 21 and a second recess 22 formed therein. The first recess 21 and the second recess 22 each open towards the surface 2a with the Z-axis direction as the depth direction. The bottom surface (first mounting surface) 21a of the first recess 21 and the bottom surface (second mounting surface) 22a of the second recess 22 are located on the same plane perpendicular to the Z-axis direction. The thickness from the bottom surfaces 21a, 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 aligned in the X-axis direction (the second direction perpendicular to the first direction). Note that in Figure 5, the light-transmitting member 3 and the adhesive members 73 and 75, which will be described later, are not shown.

[0044] The first recess 21 includes the center C of the support 2 when viewed from the Z-axis direction. The first recess 21 does not reach the outer edge 2E of the support 2 when viewed from the Z-axis direction. When viewed from the Z-axis direction, the inner edge 21E of the first recess 21 has a rectangular shape. In this embodiment, when viewed from the Z-axis direction, the inner edge 21E of the first recess 21 has a rectangular shape with the X-axis direction as its longitudinal 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.

[0045] The second recess 22 does not include the center C of the support 2 when viewed from the Z-axis direction. The second recess 22 extends to the outer edge 2E of the support 2 when viewed from the Z-axis direction. When viewed from the Z-axis direction, the inner edge 22E of the second recess 22 has a rectangular shape. In this embodiment, when viewed from the Z-axis direction, the inner edge 22E of the second recess 22 has a rectangular shape with the X-axis direction as its longitudinal direction. In this embodiment, the second recess 22 extends to the side surface 2c of the support 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 extends to the outer edge 2E of the support 2 on the short side of the second recess 22. Because the second recess 22 does not cross the support 2 when viewed from the Z-axis direction, the rigidity of the support 2 is higher compared to a configuration in which the second recess 22 crosses the support 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.

[0046] The width W2 of the second recess 22 in the Y-axis direction (a third direction perpendicular to both the first and second directions) is greater than the width W1 of the first recess 21 in the Y-axis direction. In this 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 2. In this 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.

[0047] The support 2 has an opening (light-transmitting portion) 23 and a through hole 24. The opening 23 and the through hole 24 open to the bottom surface (inner surface) 21a and the surface (outer surface) 2b of the support 2, respectively. In other words, the first recess 21 opens on the opposite side of the opening 23, with the Z-axis direction as the depth direction. The opening 23 and the through hole 24 are aligned in the X-axis direction. The opening 23 defines a cylindrical space with a center line parallel to the Z-axis direction. When viewed from the Z-axis direction, the center of the opening 23 coincides with the center C of the support 2. The inner diameter of the opening 23 is, for example, 2 mm to 15 mm.

[0048] A widened portion 25 is formed in the support 2. The widened portion 25 is widened relative to the opening of the first recess 21 on the side opposite to the second recess 22 in the X-axis direction, and on both sides in the Y-axis direction. The widened portion 25 is a recess formed in the support 2 so as to open on the surface 2a side with the Z-axis direction as the depth direction and to reach the opening of the first recess 21. In this embodiment, the width of the widened portion 25 in the Y-axis direction is equal to the width W2 of the second recess 22 in the Y-axis direction.

[0049] The support 2 includes a partition 26. The partition 26 is located between the first recess 21 and the second recess 22. The partition 26 is formed integrally with the other parts of the support 2 as a part of the support 2. In this embodiment, the partition 26 is a wall portion extending in the Y-axis direction between the bottom surface 21a of the first recess 21 and the bottom surface 22a of the second recess 22. In this embodiment, with respect to the plane in which the bottom surfaces 21a and 22a are located, the height of the partition 26 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 widening portion 25 in the Z-axis direction. The width of the partition 26 in the X-axis direction is, for example, 0.5 mm to 5 mm. The height of the partition 26 in the Z-axis direction is, for example, 0.1 mm to 2 mm.

[0050] The Fabry-Perot interference filter 10 is positioned on the support 2 with the Z-axis direction as the thickness direction, such that it overlaps with the opening 23 when viewed from the Z-axis direction. More specifically, the Fabry-Perot interference filter 10 is positioned within the first recess 21 with the Z-axis direction as the thickness direction, such that it overlaps with the opening 23 when viewed from the Z-axis direction. The Fabry-Perot interference filter 10 is in contact with the partition 26 within the first recess 21. In this embodiment, with respect to the bottom surface 21a of the first recess 21, 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 widening portion 25 in the Z-axis direction. In this embodiment, with respect to the bottom surface 21a of the first recess 21, the height of the partition 26 in the Z-axis direction is less than or equal to 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.

[0051] 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 has a rectangular shape. The Fabry-Perot interference filter 10 is positioned on the bottom surface 21a of the first recess 21 such that when viewed from the Z-axis direction, 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. The center line of the opening 18 coincides with the center line of the opening 23. In other words, 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.

[0052] The Fabry-Perot interference filter 10 is fixed to the bottom surface 21a by adhesive members 71. The adhesive members 71 are arranged in a dot pattern between the bottom surface 21a and one corner of the Fabry-Perot interference filter 10. This suppresses the stress caused by deformation of the support 2 and / or adhesive members 71 due to temperature changes from affecting the Fabry-Perot interference filter 10. The material of the adhesive members 71 is, for example, a polyimide resin, a silicone resin, an epoxy resin, an acrylic resin, or a hybrid resin thereof.

[0053] As shown in Figures 4 and 6, the light-transmitting member 3 is positioned on the support 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 positioned within 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 this embodiment, the light-transmitting member 3 covers the opening of the first recess 21 as well as a portion of the opening of the second recess 22. In this embodiment, with respect to the bottom surface 25a of the widened portion 25, 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 2 in the Z-axis direction.

[0054] The light-transmitting member 3 is a rectangular plate-shaped member with the Z-axis direction as the thickness direction and the X-axis direction as the longitudinal 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 longitudinal direction. The light-transmitting member 3 is positioned on the bottom surface 25a of the widened portion 25 such that, when viewed from the Z-axis direction, each side of the outer edge 3E is parallel to the X-axis direction or the Y-axis direction. As an example, the light-transmitting member 3 is a bandpass filter that transmits light in a predetermined wavelength range.

[0055] The light-transmitting member 3 is fixed to the bottom surface 25a and side surface 25b of the widened portion 25 by adhesive members 72 and 73. The adhesive member 72 is arranged in a dot pattern between the bottom surface 25a and one corner of the light-transmitting member 3. The adhesive member 73 is arranged along the corner formed by the side surface 25b and the surface 3a of the light-transmitting member 3. Surface 3a is the surface of the light-transmitting member 3 opposite to the first recess 21. A portion of the adhesive member 73 also extends 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 resin, silicone resin, epoxy resin, acrylic resin, or hybrid resins thereof.

[0056] As shown in Figures 4 and 5, the wiring board 4 is positioned on the support 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 board 4 is positioned 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 board 4 is in contact with the partition 26 within the second recess 22. In this embodiment, with respect to the bottom surface 22a of the second recess 22, the height of the wiring board 4 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 this embodiment, with respect to the bottom surface 22a of the second recess 22, the height of the partition 26 in the Z-axis direction is less than or equal to the height of the wiring board 4 in the Z-axis direction.

[0057] The wiring board 4 is a rectangular plate-shaped substrate with the Z-axis direction as the thickness direction and the X-axis direction as the longitudinal direction. Therefore, when viewed from the Z-axis direction, the outer edge 4E of the wiring board 4 has a rectangular shape with the X-axis direction as the longitudinal direction. The wiring board 4 is placed on the bottom surface 22a of the second recess 22 such that, when viewed from the Z-axis direction, each side of the outer edge 4E is parallel to the X-axis direction or the Y-axis direction.

[0058] The wiring board 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 parts 74a and a second part 74b. The pair of first parts 74a face each other between the bottom surface 22a and the wiring board 4 and each extends in the X-axis direction. Part of each first part 74a also extends between the side surface of the second recess 22 and the side surface of the wiring board 4. The second part 74b faces the partition 26 between the bottom surface 22a and the wiring board 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 hybrid resin thereof.

[0059] The wiring board 4 is electrically connected to the Fabry-Perot interference filter 10. More specifically, terminal 41 of the wiring board 4 is electrically connected by wire 8 to terminal 16 of the pair of terminals 16 of the Fabry-Perot interference filter 10 that is closer to the partition 26, and terminal 42 of the wiring board 4 is electrically connected by wire 8 to terminal 17 of the pair of terminals 17 of the Fabry-Perot interference filter 10 that is closer to the partition 26. The pair of terminals 41 and 42 are located in the region of the surface 4a of the wiring board 4 on the light-transmitting member 3 side that is along the partition 26. Each wire 8 passes through the gap between the partition 26 and the light-transmitting member 3. When viewed from the X-axis direction, each wire 8 is contained within the first recess 21 and the second recess 22. The width of the partition 26 in the X-axis direction is smaller than the width of the Fabry-Perot interference filter 10 in the X-axis direction. This allows the distance between the Fabry-Perot interference filter 10 and the wiring board 4 to be shortened.

[0060] The connector 5 is mounted on the surface 4a of the wiring board 4 and is electrically connected to the wiring board 4. A portion 5a of the connector 5 is located outside the side surface 2c of the support 2, via a region of the second recess 22 that extends to the side surface 2c of the support 2. A connection port 51 is provided in the portion 5a of the connector 5, opening on the side opposite to the center C of the support 2. In the Z-axis direction, the connector 5 is housed within the second recess 22. In the filter unit 1, a voltage is applied to a pair of terminals 16 and 17 from external wiring connected to the connector 5, via the wiring board 4 and a pair of wires 8.

[0061] As shown in Figures 4 and 6, an adhesive member 75 is positioned between the wiring board 4 and the light-transmitting member 3. The adhesive member 75 extends along the portion of the outer edge 3E of the light-transmitting member 3 that overlaps with the wiring board 4 when viewed from the Z-axis direction. The adhesive member 75 seals the gap between the wiring board 4 and the light-transmitting member 3 outside the pair of terminals 41 and 42 (on the opposite side from the center C of the support 2). The material of the adhesive member 75 is, for example, a polyimide resin, a silicone resin, an epoxy resin, an acrylic resin, or a hybrid resin thereof. In this embodiment, the adhesive members 74 and 75 constitute the "adhesive member 7 positioned between the wiring board 4 and the support 2, and between the wiring board 4 and the light-transmitting member 3."

[0062] As shown in Figures 4 and 7, the cover 6 is positioned 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 light-transmitting plate-shaped member positioned on the surface 2b of the support 2 with the Z-axis direction as the thickness direction. For example, the cover 6 has a circular plate shape, 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 positioned 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 hybrid 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 is large enough to prevent light from entering the through hole 24 through the cover 6. The light-shielding film 61 is, for example, a chrome-plated film.

[0063] As shown in Figure 4, in the filter unit 1, the support 2 and the light-transmitting member 3 constitute a housing 200 including a first wall portion 210, a second wall portion 220, and a surrounding portion 230. More specifically, a part of the support 2 constitutes the first wall portion 210, and a part of the light-transmitting member 3 constitutes the second wall portion 220. The other part of the support 2 and the other part of the light-transmitting member 3 constitute the surrounding portion 230. The first wall portion 210 is a wall portion having an opening 23, and specifically, it is the portion of the support 2 that overlaps with the region within 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 facing the first wall portion 210 in the Z-axis direction, and specifically, it is the portion of the light-transmitting member 3 that overlaps with the region within the first recess 21 when viewed from the Z-axis direction. The surrounding portion 230 is the part that surrounds the region between the first wall portion 210 and the second wall portion 220, and specifically, it is the part of the support 2 and the light-transmitting member 3 that surrounds the region within the first recess 21 when viewed from the Z-axis direction.

[0064] Therefore, in the filter unit 1, the following can be said. 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 toward 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 FIG. 3). The wiring board 4 is attached to the housing 200 so as not to overlap with the Fabry-Perot interference filter 10 when viewed from the Z-axis direction. The wiring board 4 is attached to the housing 200 such that the entire wiring board 4 is embedded in the surrounding portion 230. Note that "the entire wiring board 4 is embedded in the surrounding portion 230" means that the entire wiring board 4 overlaps with the surrounding portion 230 when viewed from any of the X-axis direction, Y-axis direction, and Z-axis direction. At least a part of the wiring board 4 is exposed outside the housing 200. In the present embodiment, at least a part of the wiring board 4 is exposed outside the housing 200 through a region of the opening of the second recess 22 that is not covered by the light transmission member 3 and a region of the second recess 22 that reaches the side surface 2c of the support 2.

[0065] As shown in FIG. 5, 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 board in the Y-axis direction is larger 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. Also, in the filter unit 1, it is preferable that the relationship of "W2 < 2Ws" holds.

[0066] Note that "Wf=W1" means that Wf and W1 are substantially equal, and "Ws=W2" means that Ws and W2 are substantially equal. For example, "Wf=W1" means that W1 is a value between "Wf" and "1.1Wf", and "Ws=W2" means that W2 is a value between "Ws" and "1.1Ws".

[0067] As shown in Figure 3, 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 (direction perpendicular to one side of the outer edge 10E of the Fabry-Perot interference filter 10) is greater than the diagonal length L 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 may be about 2 to 3 times the diagonal length L 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 approximately 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, which is formed as a single unit without the combination of multiple parts, includes a thickened portion that surrounds the first recess 21 and the second recess 22. The thickened portion is the part of the support 2 whose 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 thickened 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.

[0068] Furthermore, the distance D1 from the inner edge 21E of the first recess 21 to the outer edge 2E of the support 2 in a predetermined direction corresponds to the distance from the inner edge of the surrounding portion 230 to the outer edge of the surrounding portion 230 in a predetermined direction. Also, 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 a predetermined 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 a predetermined direction. [Method for manufacturing a filter unit]

[0069] The manufacturing method of the filter unit 1 described above will be explained with reference to Figure 4. First, a support 2 is prepared, and an uncured adhesive member 71 is placed on the bottom surface 21a of the first recess 21, and an uncured adhesive member 74 is placed on the bottom surface 22a of the second recess 22. Next, the Fabry-Perot interference filter 10 is placed on the bottom surface 21a of the first recess 21, and the wiring board 4 is placed on the bottom surface 22a of the second recess 22. The connector 5 is pre-mounted on the surface 4a of the wiring board 4. Next, the adhesive members 71 and 74 are cured. At this time, the Fabry-Perot interference filter 10 is fitted into the first recess 21 while in contact with the partition 26, so it is accurately positioned relative to the opening 23. Also, the wiring board 4 is fitted into the second recess 22 while in contact with the partition 26, so it is accurately positioned relative to the Fabry-Perot interference filter 10. Next, terminal 41 of the wiring board 4 is electrically connected to terminal 16 of the Fabry-Perot interference filter 10 by wire 8, and terminal 42 of the wiring board 4 is electrically connected to terminal 17 of the Fabry-Perot interference filter 10 by wire 8. Precise positioning of the wiring board 4 relative to the Fabry-Perot interference filter 10 is important for ensuring reliable wire bonding between the Fabry-Perot interference filter 10 and the wiring board 4. Of the pair of terminals 16, terminal 16 to which wire 8 is connected is located closer to the partition 26 (wiring board 4) than to the center of the Fabry-Perot interference filter 10. Similarly, of the pair of terminals 17, terminal 17 to which wire 8 is connected is located closer to the partition 26 (wiring board 4) than to the center of the Fabry-Perot interference filter 10. This allows for a shorter length for each wire 8.

[0070] Next, the uncured adhesive member 72 is placed on the bottom surface 25a of the widened portion 25. Next, the light-transmitting member 3 is placed on the bottom surface 25a of the widened portion 25. Next, the adhesive member 72 is cured. Next, the uncured adhesive member 73 is placed along the corner formed by the side surface 25b of the widened portion 25 and the surface 3a of the light-transmitting member 3, and the uncured adhesive member 75 is placed between the wiring board 4 and the light-transmitting member 3. Next, the adhesive members 73 and 75 are cured. At this time, the gas generated from the adhesive members 73 and 75 is released to the outside from inside the first recess 21 through the through hole 24. Next, the cover 6 is placed on the surface 2b of the support 2. Next, the uncured adhesive member 76 is placed along the outer edge 6E of the cover 6. Next, the adhesive member 76 is cured. The light-shielding film 61 is pre-provided on the surface 6a of the cover 6. Thus, the filter unit 1 is obtained. [Structure of the lens barrel equipped with a filter unit]

[0071] As shown in Figure 8, the lens barrel 300 comprises a cylindrical body 310, a light-gathering optical system 320 including multiple lenses, an imaging optical system 330 including multiple lenses, and the filter unit 1 described above. The lens barrel 300 is used as an interchangeable lens for a hyperspectral camera. A hyperspectral camera is a camera that can spectrally separate light into tens to hundreds of bands and acquire images for each band.

[0072] The cylindrical body 310 includes a main body 311 and a base end 312. The main body 311 holds the light-gathering optical system 320, the imaging optical system 330, and the filter unit 1. The base end 312 is configured to be detachable from the camera body of the hyperspectral camera.

[0073] The focusing optical system 320 is located in the area of ​​the main body 311 that is opposite to the base end 312. The imaging optical system 330 is located in the area of ​​the main body 311 that is on the base end 312 side. The filter unit 1 is located in the area of ​​the main body 311 that is between the focusing optical system 320 and the imaging optical system 330. The optical axes of the focusing optical system 320, the imaging optical system 330, and the optical axis of the filter unit 1 (i.e., the centerlines of the apertures 18 and 23) coincide with the centerline of the cylindrical body 310.

[0074] The focusing optical system 320 and the imaging optical system 330 constitute a non-telecentric optical system. The focusing optical system 320 is an optical system that focuses on-axis incident light and off-axis incident light. The filter unit 1 is positioned in the focusing optical system 320 at the point where the on-axis incident light and off-axis incident light intersect. The filter unit 1 functions as an aperture at this position. The imaging optical system 330 forms an image of the light that has passed through the filter unit 1 on the image sensor of a hyperspectral camera. Note that the focusing optical system 320 and the imaging optical system 330 may constitute a telecentric optical system.

[0075] The filter unit 1 is fixed to the inside of the main body 311 by being sandwiched between a flange surface 311a and a fixing ring 313 provided on the main body 311. The flange surface 311a is an inward-facing flange surface provided on the main body 311 so as to face the condensing optical system 320. The filter unit 1 is fixed to the inside of the main body 311 with its aperture 23 positioned on the condensing optical system 320 side relative to the Fabry-Perot interference filter 10. As an example, the aperture 23 of the filter unit 1 is located at the position where the on-axis incident light and the off-axis incident light of the condensing optical system 320 intersect.

[0076] The connector 5 is positioned within an opening 311b formed in the main body 311. The connection port 51 of the connector 5 is exposed to the outside of the cylindrical body 310 through the opening 311b. An adhesive member 77 is placed between the side surface of the connector 5 and the inner surface of the opening 311b. This seals the gap between the side surface of the connector 5 and the inner surface of the opening 311b. [Mechanism of Action and Effects]

[0077] In the filter unit 1, the Fabry-Perot interference filter 10 is placed inside the housing 200, and the wiring board 4 is attached to the housing 200 such that the entire wiring board 4 is embedded in the surrounding portion 230 of the housing 200. This makes the filter unit 1 thinner in the Z-axis direction, which is the optical axis direction of the Fabry-Perot interference filter 10 (i.e., the direction in which the pair of mirror portions 14 and 15 face each other), compared to a configuration in which the housing containing the Fabry-Perot interference filter 10 is placed on the wiring board. Furthermore, since the wiring board 4 is attached to the housing 200 such that the entire wiring board 4 is embedded in the surrounding portion 230 of the housing 200, electrical connections can be made from the side in the Z-axis direction, which is the optical axis direction of the Fabry-Perot interference filter 10. In addition, since there is no need to form wiring in the housing 200, the configuration of the housing 200 can be optimized. Therefore, it is suitable for placing the Fabry-Perot interference filter 10 in a narrow area in the optical axis direction.

[0078] In the filter unit 1, the housing 200 includes a support 2 that constitutes a first wall portion 210 and a surrounding portion 230, and a light-transmitting member 3 that constitutes a second wall portion 220. Adhesive members 7 (adhesive members 74, 75) are placed between the wiring board 4 and the support 2, and between the wiring board 4 and the light-transmitting member 3. This allows for the construction of a package containing the Fabry-Perot interference filter 10 using the support 2, wiring board 4, light-transmitting member 3, and adhesive members 7, while suppressing an increase in the thickness of the Fabry-Perot interference filter 10 in the Z-axis direction, which is the optical axis direction. This protects the Fabry-Perot interference filter 10 from moisture, particles, and the like.

[0079] In the filter unit 1, the Fabry-Perot interference filter 10 is located at the center C of the support 2 when viewed from the Z-axis direction. This prevents external forces from affecting the Fabry-Perot interference filter 10 even if they act on the housing 200 from the side in the Z-axis direction. Furthermore, 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 positioned on the center line of the cylindrical body 310.

[0080] In the filter unit 1, the outer edge 200E of the housing 200 is circular when viewed from the Z-axis direction. This allows for balanced suppression of external forces acting on the housing 200 from the side in the Z-axis direction, preventing those forces from affecting the Fabry-Perot interference filter 10. Furthermore, for example, if the cylindrical body 310 is cylindrical, the Fabry-Perot interference filter 10 can be easily and accurately positioned on the center line of the cylindrical body 310.

[0081] In the filter unit 1, since the housing 200 is a circular plate-shaped component, when the filter unit 1 is installed inside the cylindrical body 310, it is possible to prevent the filter unit 1 from rolling out inside the cylindrical body 310.

[0082] In the filter unit 1, the Fabry-Perot interference filter 10 is positioned within the first recess 21, and when viewed from the Z-axis direction, both the outer edge 10E of the Fabry-Perot interference filter 10 and the inner edge 21E of the first recess 21 have a rectangular shape. As a result, when viewed from the Z-axis direction, both the outer edge 10E of the Fabry-Perot interference filter 10 and the inner edge 21E of the first recess 21 have a rectangular shape, allowing for easy and accurate positioning of the Fabry-Perot interference filter 10 relative to the housing 200.

[0083] In the filter unit 1, the wiring board 4 is mounted on the housing 200 so as not to overlap with the Fabry-Perot interference filter 10 when viewed from the Z-axis direction. This makes the filter unit 1 thinner in the Z-axis direction, which is the optical axis direction of the Fabry-Perot interference filter 10.

[0084] In filter unit 1, the Fabry-Perot interference filter 10 and the wiring board 4 are arranged on the same plane (the plane on which the bottom surfaces 21a and 22a are located). This makes the filter unit 1 thinner in the Z-axis direction, which is the optical axis direction of the Fabry-Perot interference filter 10.

[0085] In the filter unit 1, a second recess 22 on which the wiring board 4 is placed is formed in the surrounding portion 230, and the second recess 22 extends to the outer edge of the surrounding portion 230 when viewed from the Z-axis direction. This allows for a simple electrical connection from the side with respect to the Z-axis direction, which is the optical axis direction of the Fabry-Perot interference filter 10.

[0086] In the filter unit 1, the housing 200 includes a partition 26 positioned between the second recess 22 and the first recess 21. This allows for easy and accurate positioning of the Fabry-Perot interference filter 10 and the wiring board 4 relative to the housing 200 by using the partition 26 as a reference.

[0087] 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. As a result, even if an external force acts on the housing 200 from the side in the Z-axis direction, it is possible to suppress the effect of that external force on the Fabry-Perot interference filter 10.

[0088] In the filter unit 1, 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" is larger than the length L of the diagonal line 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. As a result, when viewed from the Z - axis direction, the opening 23 becomes extremely small compared to the support 2, so that stray light incident on the Fabry - Perot interference filter 10 can be suppressed.

[0089] The filter unit 1 functions as an aperture between the condenser optical system 320 and the imaging optical system 330 in the above - mentioned lens barrel 300. Thereby, the depth of the object field can be increased in the hyperspectral camera to which the lens barrel 300 is attached.

[0090] 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 board 4 in the Y - axis direction, the width W1 of the first recess 2, and the width W2 of the second recess 22, the relationship of "Wf≦W1<Ws≦W2" holds. As a result, since the width W1 of the first recess 21 and the width W2 of the second recess 22 are different from each other, by using the boundary between the first recess 21 and the second recess 22 as a reference (for example, a mechanical positioning part or a reference coordinate), the positioning of the Fabry - Perot interference filter 10 and the wiring board 4 with respect to the support 2 can be easily and accurately performed. Also, compared to the case where the width W1 of the first recess 21 is added to the width W2 of the second recess 22, the strength of the support 2 can be ensured. Further, even if an external force acts on the wiring board 4 from the side in the Z - axis direction, the external force can be released from the boundary between the first recess 21 and the second recess 22 to the support 2, and the external force reaching the Fabry - Perot interference filter 10 can be suppressed. <000​​In the filter unit 1, with respect to 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 of "Wf = W1" holds. Thereby, the positioning of the Fabry - Perot interference filter 10 with respect to the housing 200 can be carried out more easily and with higher precision.

[0092] In the filter unit 1, with respect to the width Ws of the wiring board 4 in the Y - axis direction and the width W2 of the second recess 22 in the Y - axis direction, the relationship of "Ws = W2" holds. Thereby, the positioning of the wiring board 4 with respect to the housing 200 can be carried out more easily and with higher precision.

[0093] In the filter unit 1, through - holes 24 are formed in the housing 200 that open to 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. Thereby, even if gas is generated in the space inside the housing 200 during the manufacture of the filter unit 1, the gas can be released to the outside through the through - holes 24. [Modified Example]

[0094] The present invention is not limited to the above - described embodiment. 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 board 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 of "Wf ≤ W1 < Ws ≤ W2" holds (the case shown in FIG. 5), the relationship of "Wf < W1" may hold. Similarly, when the relationship of "Wf ≤ W1 < Ws ≤ W2" holds (the case shown in FIG. 5), the relationship of "Ws < W2" may hold.

[0095] Further, as shown in FIG. 9, regarding the width Wf of the Fabry-Perot interference filter 10 in the Y-axis direction, the width Ws of the wiring board 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 of "Ws ≦ W2 < Wf ≦ W1" may be satisfied. Even in this case, the positioning of the Fabry-Perot interference filter 10 and the wiring board 4 with respect to the support 2 can be easily and accurately performed. Also, compared to the case where the width W2 of the second recess 22 is combined with the width W1 of the first recess 21, the strength of the support 2 can be ensured. Further, it is possible to suppress the entry of stray light into the Fabry-Perot interference filter 10 through the second recess 22 in which the wiring board 4 is disposed. Furthermore, since the portions on both sides of the second recess 22 in the Y-axis direction of the support 2 approach the wiring board 4 compared to the case where the width W2 of the second recess 22 is combined with the width W1 of the first recess 21, the heat generated in the wiring board 4 can be efficiently dissipated to the support 2.

[0096] Also, the widened portion 25 may be widened at least in the Y-axis direction with respect to the opening of the first recess 21. As an example, as shown in FIG. 9, the widened portion 25 extends from the opening of the first recess 21 to the opening of the second recess 22 and may be widened at least in the Y-axis direction with respect to the opening of the first recess 21 and the opening of the second recess 22. This is the same not only when the relationship of "Ws ≦ W2 < Wf ≦ W1" is satisfied (the case shown in FIG. 9) but also when the relationship of "Wf ≦ W1 < Ws ≦ W2" is satisfied (the case shown in FIG. 5). When the widened portion 25 extends from the opening of the first recess 21 to the opening of the second recess 22, it is possible to more stably support the light transmission member 3 on the support 2 while suppressing an increase in the thickness in the Z-axis direction, which is the optical axis direction of the Fabry-Perot interference filter 10.

[0097] Furthermore, as shown in Figures 10(a) and (b), the filter unit 1 may also be equipped with a flexible wiring board 9 for external wiring and connection. In the example of the lens barrel shown in Figure 10(a), one end of the flexible wiring board 9 is connected to a wiring board 4, and a connector 5 connected to the other end of the flexible wiring board 9 is located inside the opening 311b of the cylindrical body 310. In this case, an adhesive member 77 is placed between the side surface of the connector 5 and the inner surface of the opening 311b. In the example of the lens barrel shown in Figure 10(b), one end of the flexible wiring board 9 is connected to a wiring board 4, and the other end of the flexible wiring board 9 is extended to the outside through the opening 311b of the cylindrical body 310. In this case, an adhesive member 77 is placed between the flexible wiring board 9 and the inner surface of the opening 311b.

[0098] Furthermore, the filter unit 1 may include a Fabry-Perot interference filter as shown in Figure 11. The Fabry-Perot interference filter 400 shown in Figure 11 will be described below. The Fabry-Perot interference filter 400 comprises a substrate layer 411, a mirror portion 412, and a driving electrode 413. The substrate layer 411 has two surfaces 411a and 411b facing each other. The substrate layer 411 is formed of a light-transmitting material. The mirror portion 412 is, for example, a metal film, a dielectric multilayer film, or a composite film thereof. The driving electrode 413 is, for example, formed of a metallic material.

[0099] The Fabry-Perot interference filter 400 further comprises a substrate layer 421, a mirror portion 422, and a driving electrode 423. The substrate layer 421 has two surfaces 421a and 421b facing each other. The substrate layer 421 is formed of a light-transmitting material. The mirror portion 422 is, for example, a metal film, a dielectric multilayer film, or a composite film thereof. The driving electrode 423 is formed of, for example, a metallic material.

[0100] A recess 414 is formed on the surface 411a of the substrate layer 411. A protrusion 415 is provided on the bottom surface 414a of the recess 414. With respect to the bottom surface 414a, the height of the end face 415a of the protrusion 415 is lower than the height of the surface 411a of the substrate layer 411. A mirror portion 412 is provided on the end face 415a of the protrusion 415. A driving electrode 413 is provided on the bottom surface 414a of the recess 414 so as to surround the protrusion 415. The driving electrode 413 is electrically connected to an electrode pad (not shown) via, for example, wiring (not shown) provided on the substrate layer 411. The electrode pad is provided, for example, in an area of ​​the substrate layer 411 that is accessible from the outside.

[0101] The surface 421b of the substrate layer 421 is joined to the surface 411a of the substrate layer 411, for example, by plasma bonding. A mirror portion 422 and a driving electrode 423 are provided on the surface 421b of the substrate layer 421. The mirror portion 422 faces the mirror portion 412 with an air gap S between them. The driving electrode 423 is provided on the surface 421b of the substrate layer 421 so as to surround the mirror portion 422, and faces the driving electrode 413 with an air gap S between them. The driving electrode 423 is electrically connected to an electrode pad (not shown) via wiring (not shown) provided on the substrate layer 421, for example. The electrode pad is provided in an area of ​​the substrate layer 421 that is accessible from the outside.

[0102] A groove 424 is formed on the surface 421a 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. The groove 424 extends in an annular shape. The portion of the substrate layer 421 surrounded by the groove 424 has a diaphragm-shaped holding portion 425 in which the pair of mirror portions 412 and 422 are movable in a direction facing each other.

[0103] The diaphragm-shaped retaining portion 425 may be configured such that a groove surrounding the mirror portion 422 and the drive electrode 423 is formed on at least one of the surfaces 421a and 421b of the substrate layer 421 when viewed from the Z-axis direction. Alternatively, the diaphragm-shaped retaining portion may be configured in the substrate layer 411 by forming a groove surrounding the mirror portion 412 and the drive electrode 413 when viewed from the Z-axis direction in the substrate layer 411. Instead of a diaphragm-shaped retaining portion, the retaining portion may be configured by a plurality of radially arranged beams.

[0104] In the Fabry-Perot interference filter 400 shown in Figure 11, when a voltage is applied to the drive electrodes 413 and 423, a potential difference is generated between the drive electrodes 413 and 423, and an electrostatic force corresponding to this potential difference is generated between the drive electrodes 413 and 423. As a result of the electrostatic force generated between the drive electrodes 413 and 423, the portion of the substrate layer 421 surrounded by the groove 424 is attracted to the substrate layer 411, and the distance between the mirror portion 412 and the mirror portion 422 is adjusted. This allows light having a wavelength corresponding to the distance between the mirror portion 412 and the mirror portion 422 to be transmitted.

[0105] Furthermore, in the filter unit 1, the outer edge 2E of the support 2 may have a shape other than circular, such as a rectangular shape, when viewed from the Z-axis direction. In the filter unit 1, the outer edge 10E of the Fabry-Perot interference filter 10, the outer edge 4E of the wiring board 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 rectangular.

[0106] In filter unit 1, the Fabry-Perot interference filter 10 may be offset from the center C of the support 2 when viewed from the Z-axis direction. In filter unit 1, the mounting surface of the support 2 on which the Fabry-Perot interference filter 10 is placed does not have to be the bottom surface 21a of the first recess 21. In filter unit 1, the mounting surface of the support 2 on which the wiring board 4 is placed does not have to be the bottom surface 22a of the second recess 22. In filter unit 1, the mounting surface of the support 2 on which the Fabry-Perot interference filter 10 is placed and the mounting surface of the support 2 on which the wiring board 4 is placed do not have to be located on the same plane.

[0107] In filter unit 1, the entire Fabry-Perot interference filter 10 does not have to be placed within the first recess 21. In filter unit 1, the entire light-transmitting member 3 does not have to be placed within the widened portion 25. In filter unit 1, the entire wiring board 4 does not have to be placed within the second recess 22. In filter unit 1, the wiring board 4 may be attached to the housing 200 such that a portion of the wiring board 4 is embedded in the surrounding portion 230. Note that "a portion of the wiring board 4 is embedded in the surrounding portion 230" means that the portion of the wiring board 4 overlaps with the surrounding portion 230 when viewed from any direction in the X-axis, Y-axis, or Z-axis direction.

[0108] In the filter unit 1, the support 2 does not necessarily include a partition 26 positioned 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 be connected to each other. If the support 2 includes a partition 26, the partition 26 may not completely separate the first recess 21 and the second recess 22, but may only partially separate them. If the support 2 includes a partition 26, the height of the partition 26 in the Z-axis direction is not limited to those described above. 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, with reference to the bottom surface 21a of the first recess 21. The height of the partition 26 in the Z-axis direction may be higher than the height of the wiring board 4 in the Z-axis direction, with reference to the bottom surface 22a of the second recess 22. The partition 26 may be formed separately from the support 2 and attached to the support 2.

[0109] 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 one direction other than the Y-axis direction may be greater than the width of the Fabry-Perot interference filter 10 in that 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 a direction perpendicular to one side of the outer edge 10E of the Fabry-Perot interference filter 10, other than the Y-axis direction, may be greater than the length 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 of the opening 23 may be smaller than the width of the Fabry-Perot interference filter 10 in the direction perpendicular to that side.

[0110] In the filter unit 1, the opening 23 was formed in the support 2 as a light-transmitting portion. However, the light-transmitting portion may be formed in the support 2 as a light-transmitting portion, for example, by filling the area within the opening 23 with a light-transmitting material, or by arranging an optical element (e.g., a lens, filter, etc.) within the opening 23. In either case, the light-transmitting portion may allow light emitted from the Fabry-Perot interference filter 10 (or Fabry-Perot interference filter 400) to pass through, or it may allow light incident on the Fabry-Perot interference filter 10 (or 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 does not need to be placed on the surface 2b of the support 2. In the filter unit 1, an anti-reflective coating may be formed on at least one of the surface 2b of the support 2 and the inner surface of the opening 23. For example, if the support 2 is made of stainless steel, the anti-reflective coating may be formed by applying a chrome plating treatment to the surface of the support 2.

[0111] In the filter unit 1, the wiring board 4 may be attached to the housing 200 such that, for example, a portion of the wiring board 4 is located within a through-hole formed in the surrounding portion 230. In this case, a portion of the wiring board 4 located within the through-hole of the surrounding portion 230 is embedded in the surrounding portion 230. [Explanation of Symbols]

[0112] 1...Filter unit, 2...Support, 2b...Surface (outer surface), 3...Light transmitting member, 4...Wiring board, 7...Adhesive member, 10,400...Fabry-Perot interference filter, 10E...Outer edge, 14,15,412,422...Mirror part, 21...First recess, 21E...Inner edge, 21a...Bottom surface (first mounting surface, inner surface), 22...Second recess, 22a...Bottom surface (second mounting surface), 23...Opening (light passing part), 24...Through hole, 26...Partition part, 200...Housing, 200E...Outer edge, 210...First wall part, 220...Second wall part, 230...Enclosing part.

Claims

1. A housing including a first wall portion having a light-transmitting portion, a second wall portion facing the first wall portion, and a surrounding portion that encloses the region between the first wall portion and the second wall portion, A Fabry-Perot interference filter is provided, which includes a pair of mirror sections facing each other in a first direction and having a variable distance between them, and is arranged within the housing such that it overlaps with the light-transmitting section when viewed from the first direction. At least a portion of it is attached to the housing so as to be embedded in the surrounding portion, and a wiring board is electrically connected to the Fabry-Perot interference filter, A filter unit comprising an adhesive member disposed between the wiring board and the housing.

2. The housing includes a support that constitutes the first wall and the surrounding portion, and a light-transmitting member that constitutes the second wall, The filter unit according to claim 1, wherein the adhesive member is disposed between the wiring board and the support, and between the wiring board and the light-transmitting member.

3. The filter unit according to claim 1, 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 has a circular shape.

5. The first wall portion and the surrounding portion define the first recess, The Fabry-Perot interference filter is located within the first recess, The filter unit according to claim 1, wherein, 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 in shape.

6. The filter unit according to claim 1, wherein the wiring board is mounted on the housing such that it does not overlap with the Fabry-Perot interference filter when viewed from the first direction.

7. The Fabry-Perot interference filter is positioned on the first mounting surface of the first wall portion, The aforementioned wiring board is positioned on the second mounting surface of the surrounding portion. The filter unit according to claim 6, wherein the first mounting surface and the second mounting surface are located on the same plane.

8. The surrounding portion has a second recess formed therein that opens toward the second wall portion with the first direction as the depth direction, The second recess extends to the outer edge of the surrounding portion when viewed from the first direction. The filter unit according to claim 1, wherein the wiring board is disposed within the second recess.

9. The first wall portion and the surrounding portion define the first recess, The surrounding portion has a second recess formed therein that opens toward the second wall portion with the first direction as the depth direction, The Fabry-Perot interference filter is located within the first recess, The wiring board is placed in the second recess, The filter unit according to claim 1, wherein the housing further includes a partition disposed between the first recess and the second recess.

10. The first wall portion and the surrounding portion define the first recess, The Fabry-Perot interference filter is located within the first recess, The filter unit according to claim 1, wherein, 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 one direction.

11. The first wall portion and the surrounding portion define the first recess, The Fabry-Perot interference filter is located within the first recess, The light-transmitting 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 has a rectangular shape. 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. The filter unit according to claim 1, wherein, 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 one side.

12. The first wall portion and the surrounding portion define the first recess, The surrounding portion has a second recess formed therein that opens toward the second wall portion with the first direction as the depth direction, The first recess and the second recess are aligned in a second direction perpendicular to the first direction, The Fabry-Perot interference filter is located within the first recess, The wiring board is placed in the second recess, The filter unit according to claim 1, wherein the width of the Fabry-Perot interference filter in a third direction perpendicular to both the first and second directions is Wf, the width of the wiring board in the third direction is Ws, the width of the first recess in the third direction is W1, and the width of the second recess in the third direction is W2, such that the relationship "Wf ≤ W1 < Ws ≤ W2" or "Ws ≤ W2 < Wf ≤ W1" holds.

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

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

15. The filter unit according to claim 1, wherein the housing has through holes formed that open to the inner surface and the outer surface of the housing.

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