Spectroscopic module and method for manufacturing spectroscopic module

Abstract

This spectroscopic module comprises: a spectroscopic unit having a Fabry-Perot interference filter and a housing that accommodates the Fabry-Perot interference filter; a package having a body part and a cover part; and a fastening shaft member inserted into a hole formed in the package. The cover part includes an aperture member in which an aperture and a positioning part for positioning the aperture member with respect to the housing are formed, and an intermediate member. The hole is a first hole configured to include a hole part formed in the aperture member and a hole part formed in the intermediate member. The hole part formed in the aperture member is an enlarged hole part having an inner edge larger than the outer edge of the fastening shaft member in a cross-section perpendicular to the axial direction of the fastening shaft member.

Description

Spectroscopic Module and Method for Manufacturing the Same

[0001] The present disclosure relates to a spectroscopic module and a method for manufacturing the same.

[0002] A spectroscopic module including a spectroscopic unit, a light source, and a package housing the spectroscopic unit and the light source is known (see, for example, Patent Document 1). The spectroscopic unit includes a Fabry-Perot interference filter including a pair of mirror portions with variable distances from each other, a photodetector that detects light transmitted through the Fabry-Perot interference filter, and a housing that houses the Fabry-Perot interference filter and the photodetector. In such a spectroscopic module, while the distance between the pair of mirror portions is changed in the Fabry-Perot interference filter, light transmitted through the pair of mirror portions among the light incident on the spectroscopic module is detected by the photodetector, thereby obtaining the spectral spectrum of the light to be measured.

[0003] Japanese Patent Application Laid-Open No. 2021-60249

[0004] The spectroscopic module as described above can be used for reflection measurement in which light irradiation and signal light detection are performed with the outer surface of the package facing the measurement object. Further, the spectroscopic module may be used for transmission measurement in which signal light transmitted through the measurement object is incident on the spectroscopic unit using a light source outside the spectroscopic module. As another example, the spectroscopic module may be used for measurement in which signal light from a measurement object at a position separated from the spectroscopic module is incident on an optical fiber, and the signal light is detected by emitting the signal light from the emission end of the optical fiber facing the light incident aperture of the housing toward the housing.

[0005] In order to cope with such various measurement methods, an aperture member (a member in which an aperture is formed), which is a part of the package, may be removed and an attachment according to the measurement method may be attached. Therefore, depending on the usage mode of the spectroscopic module, the attachment and removal of the aperture member may be performed. When attaching the aperture member, it is necessary to perform visual alignment of the aperture, but there is a risk that the measurement performance of the spectroscopic module may deteriorate if the alignment of the aperture is not properly performed.

[0006] This disclosure aims to provide a spectroscopic module capable of improving measurement performance, and a method for manufacturing such a spectroscopic module.

[0007] A spectroscopic module in one aspect of the present disclosure is a spectroscopic module comprising: [1] "a spectroscopic unit having a Fabry-Perot interference filter including a pair of mirror portions whose distance from each other is variable; a housing having an opening facing the Fabry-Perot interference filter in the opposing direction of the pair of mirror portions and housing the Fabry-Perot interference filter; a package housing the spectroscopic unit having a main body portion to which the spectroscopic unit is fixed; a cover portion covering the spectroscopic unit; and a fastening shaft member inserted into a hole comprising a hole formed in the main body portion and a hole formed in the cover portion, and fixing the cover portion to the main body portion, wherein the cover portion has an aperture facing the opening in the opposing direction of the pair of mirror portions and a positioning portion for positioning the cover portion with respect to the housing, and the hole formed in the main body portion or the hole formed in the cover portion is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member."

[0008] In the above-described spectroscopic module, the cover portion has an aperture facing the opening of the housing in the opposing direction of the pair of mirror portions, and a positioning portion for positioning the cover portion relative to the housing. The positioning portion formed in the cover portion allows for easy and accurate alignment of the aperture of the cover portion with the opening of the housing. This ensures that signal light from the object to be measured is reliably incident on the Fabry-Perot interference filter through the aperture and the opening of the housing. Furthermore, the hole formed in the main body portion or the hole formed in the cover portion is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member. As a result, when the fastening shaft member is inserted into the hole, the relative position of the cover portion and the main body portion can move in a direction perpendicular to the opposing direction of the pair of mirror portions. Therefore, when the cover portion is fixed to the main body portion by the fastening shaft member, even if the positioning portion comes into contact with the housing, excessive stress is not applied to the spectroscopic unit, and displacement, damage, etc., of the spectroscopic unit can be suppressed. Thus, the above-described spectroscopic module can improve measurement performance.

[0009] A spectroscopic module in one aspect of the present disclosure includes: [2] a spectroscopic unit having a Fabry-Perot interference filter including a pair of mirrors whose distance from each other is variable; a housing having an opening facing the Fabry-Perot interference filter in the opposing direction of the pair of mirrors, and housing the Fabry-Perot interference filter; a package having a main body to which the spectroscopic unit is fixed; a cover portion covering the spectroscopic unit; and a fastening shaft member inserted into a hole formed in the package, wherein the cover portion has an aperture facing the opening in the opposing direction of the pair of mirrors, and a positioning portion for positioning the aperture member relative to the housing; and an intermediate member disposed between the main body and the aperture member. A spectroscopic module comprising, wherein the hole is a first hole comprising a first hole formed in the aperture member and a second hole formed in the intermediate member, or a second hole comprising a third hole formed in the main body and a fourth hole formed in the intermediate member, wherein when the hole is the first hole, the fastening shaft member fixes the aperture member to the intermediate member, and the first hole or the second hole is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member, wherein when the hole is the second hole, the fastening shaft member fixes the intermediate member to the main body, and the third hole or the fourth hole is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member.

[0010] In the above-described spectroscopic module, the aperture member of the cover portion has an aperture facing the opening of the housing in the opposing direction of the pair of mirror portions, and a positioning portion for positioning the aperture member relative to the housing. The positioning portion formed on the aperture member allows for easy and accurate alignment of the aperture of the aperture member with the opening of the housing. This ensures that signal light from the object to be measured is reliably incident on the Fabry-Perot interference filter through the aperture and the opening of the housing. Furthermore, when a fastening shaft member is inserted into a first hole which includes a first hole formed in the aperture member and a second hole formed in the intermediate member, the first hole or the second hole is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member in a cross-section perpendicular to the axial direction of the fastening shaft member. As a result, when the fastening shaft member is inserted into the first hole, the relative position of the aperture member and the intermediate member can move in a direction perpendicular to the opposing direction of the pair of mirror portions. Therefore, when the aperture member is fixed to the intermediate member by the fastening shaft member, even if the positioning part comes into contact with the housing, excessive stress is not applied to the spectroscopic unit, and displacement, damage, etc., of the spectroscopic unit can be suppressed. Furthermore, when the fastening shaft member is inserted into the second hole, which is composed of a third hole formed in the main body and a fourth hole formed in the intermediate member, the third hole or the fourth hole is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member in a cross-section perpendicular to the axial direction of the fastening shaft member. As a result, when the fastening shaft member is inserted into the second hole, the relative position of the main body and the intermediate member can move in a direction perpendicular to the opposing direction of the pair of mirror portions. Therefore, when the intermediate member is fixed to the main body by the fastening shaft member, even if the positioning part comes into contact with the housing, excessive stress is not applied to the spectroscopic unit, and displacement, damage, etc., of the spectroscopic unit can be suppressed. Thus, the above spectroscopic module can improve measurement performance.

[0011] One aspect of the present disclosure is a spectroscopic module [3] "the positioning portion is in contact with the housing, and is the spectroscopic module described in [1] or [2] above." In this case, the alignment of the aperture of the cover portion and the opening of the housing can be performed more easily and accurately.

[0012] One aspect of the present disclosure is a spectroscopic module according to any one of [1] to [3] above, wherein the positioning portion is formed to sandwich the housing in a direction perpendicular to the opposing direction of the pair of mirror portions. In this case, the alignment of the aperture of the cover portion and the opening of the housing can be performed more easily and accurately.

[0013] One aspect of the present disclosure is a spectroscopic module according to any one of [1] to [4] above, wherein, when viewed from opposite directions of the pair of mirror portions, the positioning portion is formed continuously so as to surround the outer edge of the housing. In this case, alignment between the aperture of the cover portion and the opening of the housing can be performed more easily and accurately.

[0014] A spectroscopic module in one aspect of the present disclosure may be [6] "a spectroscopic module according to any one of [1] to [5] above, further comprising a substrate housed in the package, wherein the spectroscopic unit is disposed on the substrate and fixed to the main body via the substrate." In this case, the cover portion (aperture member) and the housing of the spectroscopic unit can be aligned in a stable state with the spectroscopic unit mounted on the substrate.

[0015] A spectroscopic module in one aspect of the present disclosure may be [7] "a spectroscopic module according to any one of [1] to [6] above, further comprising a light source that emits light, wherein the housing and the light source are arranged adjacent to each other." In this case, the spectroscopic module can be used as a reflective spectroscopic module.

[0016] A spectroscopic module in one aspect of the present disclosure may be [8] "a spectroscopic module according to any one of [1] to [7] above, wherein a space for housing the housing is formed inside the cover portion, and the inner surface of the cover portion defining the space is formed of a material including at least one of aluminum, silver, and gold." In this case, for example, when the spectroscopic module is used as a reflective spectroscopic module, the utilization efficiency of the signal light incident on the spectroscopic module can be increased and the signal-to-noise ratio can be improved.

[0017] One aspect of the present disclosure is a spectroscopic module as described in [2] above, wherein in the opposing direction of the pair of mirror portions, the surface of the intermediate member opposite to the main body portion is further away from the main body portion than the surface of the housing opposite to the main body portion. In this case, for example, when changing the aperture member to change the diameter of the aperture or to guide signal light through an optical fiber from the outside (when removed), the taller intermediate member remains, thereby protecting the housing.

[0018] A spectroscopic module in one aspect of the present disclosure may be

[10] "a spectroscopic module according to [2] above, comprising a first fastening shaft member and a second fastening shaft member, each of which is the fastening shaft member, wherein the package has a pair of holes, each of which is the hole, one of the pair of holes is the first hole, the other of the pair of holes is the second hole, the first fastening shaft member is inserted into the first hole, and the second fastening shaft member is inserted into the second hole." In this case, when fixing the aperture member to the intermediate member with the fastening shaft member, and when fixing the intermediate member to the main body with the fastening shaft member, for the reasons described above, displacement, damage, etc. of the spectroscopic unit can be suppressed. Therefore, measurement performance can be further improved.

[0019] One aspect of the present disclosure is a spectroscopic module according to any one of [1] to

[10] above, wherein in a direction perpendicular to the axial direction of the fastening shaft member, the width of the enlarged hole is greater than the width of the fastening shaft member by a length of 30% or more of the width of the fastening shaft member. In this case, the relative position of each of the above-mentioned parts is moved more reliably, so that displacement, damage, etc. of the spectroscopic unit can be further suppressed. As a result, the measurement performance can be further improved.

[0020] A method for manufacturing a spectroscopic module according to one aspect of the present disclosure includes:

[12] a spectroscopic unit having a Fabry-Perot interference filter including a pair of mirror portions whose distance from each other is variable; a housing having an opening facing the Fabry-Perot interference filter in the opposing direction of the pair of mirror portions and housing the Fabry-Perot interference filter; a package housing the spectroscopic unit having a main body portion to which the spectroscopic unit is fixed; a cover portion covering the spectroscopic unit; and a fastening shaft member inserted into a hole formed in the package, wherein the cover portion includes an aperture member having an aperture facing the opening in the opposing direction of the pair of mirror portions and a positioning portion for positioning the cover portion relative to the housing; and an intermediate member disposed between the main body portion and the aperture member, wherein the hole is a first hole comprising a first hole formed in the aperture member and a second hole formed in the intermediate member, or a second hole comprising a third hole formed in the main body portion and a fourth hole formed in the intermediate member A method for manufacturing a spectroscopic module, comprising the steps of: preparing the main body on which the spectroscopic unit is arranged; arranging the cover on the main body such that the intermediate member is positioned between the main body and the aperture member; positioning the aperture member relative to the housing using the positioning unit; if the hole is the first hole, fixing the aperture member to the intermediate member with the fastening shaft member inserted into the first hole; if the hole is the second hole, fixing the intermediate member to the main body with the fastening shaft member inserted into the second hole, wherein if the hole is the first hole, the first hole portion or the second hole portion is an enlarged hole portion having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member; and if the hole is the second hole, the third hole portion or the fourth hole portion is an enlarged hole portion having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member.

[0021] In the above-described method for manufacturing the spectroscopic module, as described above, the positioning portion formed on the aperture member allows for easy and accurate alignment between the aperture of the aperture member and the opening of the housing. This ensures that signal light from the object to be measured is reliably incident on the Fabry-Perot interference filter through the aperture and the opening of the housing. Furthermore, when the fastening shaft member is inserted into the first hole, which includes the first hole formed in the aperture member and the second hole formed in the intermediate member, when the fastening shaft member fixes the aperture member to the intermediate member, for the reasons described above, even if the positioning portion comes into contact with the housing, excessive stress is not applied to the spectroscopic unit, thereby suppressing displacement, damage, etc. of the spectroscopic unit. Furthermore, when the fastening shaft member is inserted into the second hole, which includes the third hole formed in the main body and the fourth hole formed in the intermediate member, when the fastening shaft member fixes the intermediate member to the main body, for the reasons described above, even if the positioning portion comes into contact with the housing, excessive stress is not applied to the spectroscopic unit, thereby suppressing displacement, damage, etc. of the spectroscopic unit. Therefore, according to the above-described method for manufacturing the spectroscopic module, a spectroscopic module capable of improving measurement performance can be manufactured.

[0022] One aspect of the present disclosure is a method for manufacturing a spectroscopic module, which may be

[13] "the method for manufacturing a spectroscopic module according to

[12] , wherein in a direction perpendicular to the axial direction of the fastening shaft member, the width of the enlarged hole is greater than the width of the fastening shaft member by a length of 30% or more of the width of the fastening shaft member." In this case, the relative positional movement of each of the above-mentioned components is performed more reliably, so that misalignment, damage, etc. of the spectroscopic unit can be further suppressed. As a result, the measurement performance of the manufactured spectroscopic module can be further improved.

[0023] This disclosure makes it possible to provide a spectroscopic module that can improve measurement performance, and a method for manufacturing such a spectroscopic module.

[0024] Figure 1 is a cross-sectional view of a spectroscopic unit applied to a spectroscopic module of one embodiment. Figure 2 is a perspective view of the Fabry-Perot interference filter shown in Figure 1. Figure 3 is a cross-sectional view of the Fabry-Perot interference filter along the line III-III shown in Figure 2. Figure 4 is a perspective view of a spectroscopic module of one embodiment. Figure 5 is a perspective view of the internal structure of the spectroscopic module shown in Figure 4. Figure 6 is a perspective view of the spectroscopic module shown in Figure 4. Figure 7 is a cross-sectional view of the spectroscopic module along the line VII-VII shown in Figure 4. Figure 8 is a cross-sectional perspective view of the spectroscopic module along the line VIII-VIII shown in Figure 4. Figure 9 is a cross-sectional view of the spectroscopic module along the line IX-IX shown in Figure 4. Figure 10 is a schematic cross-sectional view of a positioning unit according to one embodiment. Figure 11 is a plan view showing a part of the spectroscopic module shown in Figure 4. Figure 12 is a schematic cross-sectional view of a positioning unit according to a modified example. Figure 13 is a schematic cross-sectional view of a positioning unit according to a modified example. Figure 14 is a schematic cross-sectional view of a positioning unit according to a modified example. Figure 15 is a schematic cross-sectional view showing the positioning part according to a modified example. Figure 16 is a schematic cross-sectional view showing the positioning part according to a modified example. Figure 17 is a schematic cross-sectional view showing the positioning part according to a modified example. Figure 18 is a schematic cross-sectional view showing the positioning part according to a modified example. Figure 19 is a schematic cross-sectional view showing the positioning part according to a modified example.

[0025] An example of this disclosure 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 photodetector element]

[0026] Prior to describing a spectroscopic module of one embodiment, a spectroscopic unit 1 applied to the spectroscopic module will be described. As shown in Figure 1, the spectroscopic unit 1 comprises a Fabry-Perot interference filter 10 and a housing 2 that houses the Fabry-Perot interference filter 10. The specific configuration of the Fabry-Perot interference filter 10 will be described later. The housing 2 is a CAN package having a stem 3 and a cap 4. The cap 4 includes a side wall 5 and a top wall 6. The side wall 5 and the top wall 6 are integrally formed from a metal material. The top wall 6 is integrally formed with the side wall 5 so as to cover one opening of the cylindrical (in this example, cylindrical) side wall 5. The stem 3 is made of a metal material. The stem 3 is hermetically joined to the side wall 5 so as to cover the other opening of the cylindrical side wall 5.

[0027] A wiring board 7 is fixed to the inner surface 3a of the stem 3. The substrate material of the wiring board 7 is, for example, silicon, ceramic, quartz, glass, plastic, etc. A photodetector 8 and a temperature compensation element such as a thermistor (not shown) are mounted on the wiring board 7. The photodetector 8 is, for example, an infrared detector. As an infrared detector, for example, a quantum type sensor using InGaAs, a thermopile, or a bolometer can be used. When detecting light in the ultraviolet, visible, and near-infrared wavelength ranges, for example, a silicon photodiode can be used as the photodetector 8. The light-receiving area of ​​the photodetector 8 may be composed of a single photodetector having a single light-receiving part, or it may be composed of a single photodetector having multiple light-receiving parts arranged in an array. The light-receiving area of ​​the photodetector 8 may be composed of multiple photodetectors.

[0028] Multiple spacers 9 are fixed to the wiring board 7. The material of each spacer 9 is, for example, silicon, ceramic, quartz, glass, or plastic. A Fabry-Perot interference filter 10 is fixed to the multiple spacers 9. That is, the Fabry-Perot interference filter 10 is supported by the multiple spacers 9. The light-transmitting region 10a of the Fabry-Perot interference filter 10 faces the light-receiving portion of the photodetector 8. Note that the spacers 9 may be formed integrally with the wiring board 7. Alternatively, the Fabry-Perot interference filter 10 may be supported by a single spacer 9.

[0029] Multiple lead pins 11 are fixed to the stem 3. Each lead pin 11 penetrates the stem 3, with electrical insulation and airtightness ensured between it and the stem 3 by an insulating member 17. Each lead pin 11 is electrically connected via a wire 12 to the electrode pads provided on the wiring board 7, the terminals of the photodetector 8, the terminals of the temperature compensation element, and the terminals of the Fabry-Perot interference filter 10, respectively. In the spectroscopic unit 1, electrical signals are input and output to the photodetector 8, the temperature compensation element, and the Fabry-Perot interference filter 10, respectively, via the multiple lead pins 11.

[0030] The housing 2 has an opening 20. The opening 20 is formed in the top wall 6 of the cap 4 so as to face the light transmission region 10a of the Fabry-Perot interference filter 10. A light-transmitting member 13 is hermetically bonded to the inner surface 6a of the top wall 6. The light-transmitting member 13 closes the opening 20. The light-transmitting member 13 has a light-incident surface 13a and a light-emitting surface 13b, as well as a side surface 13c, which are opposite each other. The light-incident surface 13a of the light-transmitting member 13 is substantially flush with the outer surface 6b of the top wall 6 in the opening 20. The side surface 13c of the light-transmitting member 13 is in contact with the inner surface 5a of the side wall 5 of the cap 4. Such a light-transmitting member 13 is formed by placing glass pellets inside the cap 4 with the opening 20 facing downwards and melting the glass pellets.

[0031] A bandpass filter 14 is fixed to the light-emitting surface 13b of the light-transmitting member 13 by a light-transmitting adhesive member 15. The bandpass filter 14 has a light-incident surface 14a and a light-emitting surface 14b, as well as a side surface 14c that are opposite to each other. The side surface 14c of the bandpass filter 14 is spaced apart from the inner surface 5a of the side wall 5 of the cap 4. As an example, the bandpass filter 14 is made of a light-transmitting member formed in the shape of a rectangular plate from a light-transmitting material (e.g., silicon, glass, etc.) and a dielectric multilayer film (e.g., TiO) formed on the surface of the light-transmitting member opposite to the opening 20. ２ Ta ２ O ５ High refractive index materials such as SiO ２ MgF ２ It includes a multilayer film consisting of a combination of low refractive index materials such as the above. The dielectric multilayer film may be formed on the surface of the light-transmitting member on the side of the opening 20.

[0032] The light-transmitting section 16 is composed of a light-transmitting member 13, an adhesive member 15, and a bandpass filter 14. In other words, the light-transmitting section 16 includes a light-transmitting member 13 that closes the opening 20, and a bandpass filter 14 positioned on the opposite side of the opening 20 from the light-transmitting member 13. The light-incident surface 16a of the light-transmitting section 16 is the light-incident surface 13a of the light-transmitting member 13, and the light-emitting surface 16b of the light-transmitting section 16 is the light-emitting surface 14b of the bandpass filter 14. The light-emitting surface 16b of the light-transmitting section 16 is located inside the housing 2.

[0033] The spectroscopic unit 1 includes an aperture section 51A having an aperture 50. The aperture 50 is a light-passing hole located within the housing 2 between the light-emitting surface 16b of the light-transmitting section 16 and the Fabry-Perot interference filter 10. The aperture section 51A is composed of a plate-shaped first surrounding section 52. When viewed from direction A, the first surrounding section 52 continuously surrounds the aperture 50. Direction A is the opposing direction of the pair of mirror sections (the first mirror section 35 and the second mirror section 36, described later) of the Fabry-Perot interference filter 10. When viewed from direction A, the aperture 50 is located inside the opening 20 of the housing 2. The first surrounding section 52 is positioned within the housing 2 between the light-transmitting section 16 and the Fabry-Perot interference filter 10. The first surrounding section 52 has a pair of opposing surfaces 52a, 52b and a side surface 52c. Surface 52a is the surface on the light-transmitting portion 16 side and is in contact with the light-emitting surface 16b of the light-transmitting portion 16 (i.e., the light-emitting surface 14b of the bandpass filter 14). Surface 52b is the surface on the Fabry-Perot interference filter 10 side and is spaced apart from the Fabry-Perot interference filter 10.

[0034] Of the outer surface of the first surrounding portion 52, at least the surface 52b on the Fabry-Perot interference filter 10 side has light-absorbing properties. For example, the outer surface of the first surrounding portion 52, which is formed in a plate shape from aluminum, stainless steel, etc., can be subjected to chrome plating, black anodizing, electroless nickel plating, or black paint coating (a roughening treatment may also be applied), thereby imparting light-absorbing properties to the outer surface of the first surrounding portion 52 for light in the visible to near-infrared wavelength range. Note that not only surface 52b, but also surface 52a may have light-absorbing properties.

[0035] The positioning of the aperture portion 51A in the direction perpendicular to direction A is performed by the first surrounding portion 52 and the housing 2. Specifically, the positioning of the aperture portion 51A in the direction perpendicular to direction A is performed by the fit between the side surface 52c of the first surrounding portion 52 and the inner surface 5a of the side wall 5 of the cap 4. The positioning of the aperture portion 51A in direction A is performed by the first surrounding portion 52 and the light-transmitting portion 16. Specifically, the positioning of the aperture portion 51A in direction A is performed by the contact between the surface 52a of the first surrounding portion 52 and the light-emitting surface 16b of the light-transmitting portion 16.

[0036] With the aperture portion 51A positioned, the first enclosing portion 52 is fixed to at least one of the housing 2 and the light-transmitting portion 16. Specifically, the first enclosing portion 52 is fixed to at least one of the housing 2 and the light-transmitting portion 16 by at least one of the following: an adhesive member (not shown) positioned between the side surface 14c of the bandpass filter 14 and the inner surface 5a of the side wall 5; an adhesive member (not shown) positioned at the corner formed by the surface 52b of the first enclosing portion 52 and the inner surface of the side wall 5; and an adhesive member (not shown) positioned between the light-emitting surface 14b of the bandpass filter 14 and the surface 52a of the first enclosing portion 52.

[0037] The opening 20 of the housing 2, the aperture 50 of the aperture section 51A, the light transmission region 10a of the Fabry-Perot interference filter 10, and the light receiving region of the photodetector 8 are aligned in this order on a straight line L. When viewed from a direction parallel to the straight line L, the straight line L passes through the centers of the opening 20, the aperture 50, the light transmission region 10a, and the light receiving region, respectively. In other words, in the spectral unit 1, the Fabry-Perot interference filter 10 is positioned within the housing 2 on the opposite side of the opening 20 from the light emission surface 16b of the light transmission section 16, and the photodetector 8 is positioned within the housing 2 on the opposite side of the opening 20 from the Fabry-Perot interference filter 10.

[0038] In the spectroscopic unit 1 configured as described above, when the light to be measured is incident on the light transmission region 10a of the Fabry-Perot interference filter 10 via the aperture 20, the light transmission section 16 (i.e., the light transmission member 13, the adhesive member 15, and the bandpass filter 14) and the aperture 50, light of a predetermined wavelength from the light to be measured is transmitted through the pair of mirror sections of the Fabry-Perot interference filter 10. The light transmitted through the pair of mirror sections of the Fabry-Perot interference filter 10 is incident on the photodetector 8 and detected by the photodetector 8. As an example, in order to obtain the spectral spectrum of the light to be measured, the voltage applied to the Fabry-Perot interference filter 10 is changed (i.e., the distance between the pair of mirror sections in the Fabry-Perot interference filter 10 is changed), and the light transmitted through the light transmission region 10a of the Fabry-Perot interference filter 10 is detected by the photodetector 8. [Configuration of the Fabry-Perot interference filter]

[0039] As shown in Figure 2, the Fabry-Perot interference filter 10 has a light-transmitting region 10a. For example, the Fabry-Perot interference filter 10 has a rectangular plate shape, and the light-transmitting region 10a has a cylindrical shape. As shown in Figure 3, the Fabry-Perot interference filter 10 includes a pair of mirror sections, a first mirror section 35 and a second mirror section 36. The distance between the first mirror section 35 and the second mirror section 36 in the light-transmitting region 10a is variable. The first mirror section 35 and the second mirror section 36 face each other in a direction parallel to the straight line L. As described above, the direction in which the first mirror section 35 and the second mirror section 36 face each other is direction A, and direction A is along the straight line L.

[0040] The Fabry - Perot interference filter 10 includes a substrate 21. On the surface 21a on the light incident side of the substrate 21, an antireflection layer 31, a first laminate 32, an intermediate layer 33, and a second laminate 34 are laminated in this order. A gap (air gap) S is formed by a frame - shaped intermediate layer 33 between the first laminate 32 and the second laminate 34. The material of the substrate 21 is, for example, silicon, quartz, glass, etc. When the material of the substrate 21 is silicon, the materials of the antireflection layer 31 and the intermediate layer 33 are, for example, silicon oxide, etc. The thickness of the intermediate layer 33 is, for example, an integer multiple of 1 / 2 of the design center wavelength. Note that the thickness of the intermediate layer 33 may be made larger than an integer multiple of 1 / 2 of the design center wavelength as needed.

[0041] The portion of the first laminate 32 corresponding to the light transmission region 10a functions as a first mirror portion 35. The first mirror portion 35 is supported by the substrate 21 via the antireflection layer 31. As an example, the first laminate 32 is formed by alternately laminating a plurality of polysilicon layers and a plurality of silicon nitride layers one by one. The optical thickness of each layer constituting the first mirror portion 35 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 the silicon nitride layer.

[0042] The portion of the second laminate 34 corresponding to the light transmission region 10a functions as a second mirror portion 36 facing the first mirror portion 35 through the gap S. The second mirror portion 36 is supported by the substrate 21 via the antireflection layer 31, the first laminate 32, and the intermediate layer 33. As an example, the second laminate 34 is formed by alternately laminating a plurality of polysilicon layers and a plurality of silicon nitride layers one by one. The optical thickness of each layer constituting the second mirror portion 36 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 the silicon nitride layer.

[0043] In the second laminate 34, in a portion corresponding to the gap S, a plurality of through-holes 34b are formed so as to reach the gap S from the surface 34a on the side opposite to the gap S in the second laminate 34. The plurality of through-holes 34b are formed to such an extent that they do not substantially affect the function of the second mirror portion 36. The plurality of through-holes 34b were used when forming the gap S by removing a part of the intermediate layer 33 by etching.

[0044] On the first mirror portion 35, a first electrode 22 is formed so as to surround the light transmission region 10a. On the first mirror portion 35, a second electrode 23 is formed so as to include the light transmission region 10a. Each of the first electrode 22 and the second electrode 23 is formed by doping a part of the polysilicon layer with impurities to lower the resistance of the part. The size of the second electrode 23 is substantially the same as the size of the light transmission region 10a.

[0045] On the second mirror portion 36, a third electrode 24 is formed. The third electrode 24 faces the first electrode 22 and the second electrode 23 via the gap S in the direction A. The third electrode 24 is formed by doping a part of the polysilicon layer with impurities to lower the resistance of the part.

[0046] In the Fabry - Perot interference filter 10, the second electrode 23 is located on the same plane as the first electrode 22 in a direction perpendicular to the direction A. The distance between the second electrode 23 and the third electrode 24 is substantially the same as the distance between the first electrode 22 and the third electrode 24. When viewed from the direction A, the second electrode 23 is surrounded by the first electrode 22.

[0047] In the Fabry - Perot interference filter 10, a pair of terminals 25 are provided so as to sandwich the light transmission region 10a. Each terminal 25 is disposed in a through-hole reaching from the surface 34a of the second laminate 34 to the first laminate 32. Each terminal 25 is electrically connected to the first electrode 22 via a wiring 22a.

[0048] The Fabry-Perot interference filter 10 is provided with a pair of terminals 26 that straddle the light-transmitting region 10a. Each terminal 26 is located in a through-hole extending from the surface 34a of the second laminate 34 to the intermediate layer 33. Each terminal 26 is electrically connected to the second electrode 23 via wiring 23a and to the third electrode 24 via wiring 24a. The direction in which the pair of terminals 26 are aligned across the light-transmitting region 10a is perpendicular to the direction in which the pair of terminals 25 are aligned across the light-transmitting region 10a (see Figure 2).

[0049] A pair of trenches 27 are formed in the first laminate 32. Each trench 27 extends in an annular shape so as to surround the portion of the wiring 23a that extends from each terminal 26 along direction A. Each trench 27 electrically insulates the first electrode 22 from the wiring 23a. A trench 28 is formed in the first laminate 32. The trench 28 extends in an annular shape along the inner edge of the first electrode 22. The trench 28 electrically insulates the first electrode 22 from the second electrode 23. The areas within each trench 27, 28 may be filled with insulating material or may be voids.

[0050] A pair of trenches 29 are formed in the second laminate 34. Each trench 29 extends in an annular shape so as to surround each terminal 25. Each trench 29 electrically insulates each terminal 25 from the third electrode 24. The area within each trench 29 may be filled with insulating material or may be an empty space.

[0051] On the light-emitting surface 21b of the substrate 21, an anti-reflective layer 41, a third laminate 42, an intermediate layer 43, and a fourth laminate 44 are laminated in this order. The anti-reflective layer 41 and the intermediate layer 43 have the same configuration as the anti-reflective layer 31 and the intermediate layer 33, respectively. The third laminate 42 and the fourth laminate 44 have a laminated structure that is symmetrical to the first laminate 32 and the second laminate 34 with respect to the substrate 21, respectively. The anti-reflective layer 41, the third laminate 42, the intermediate layer 43, and the fourth laminate 44 have the function of suppressing warping of the substrate 21.

[0052] An opening 40a is formed in the third laminate 42, the intermediate layer 43, and the fourth laminate 44 so as to include a light-transmitting region 10a. When viewed from direction A, the size of the opening 40a is approximately the same as the size of the light-transmitting region 10a. The opening 40a opens on the light-emitting side, and the bottom surface of the opening 40a extends to the anti-reflective layer 41. A light-shielding layer 45 is formed on the light-emitting surface of the fourth laminate 44. The material of the light-shielding layer 45 is, for example, aluminum. A protective layer 46 is formed on the surface of the light-shielding layer 45 and the inner surface of the opening 40a. The material of the protective layer 46 is, for example, aluminum oxide. Note that by making the thickness of the protective layer 46 100 nm or less (preferably about 30 nm), the optical influence of the protective layer 46 can be ignored.

[0053] In the Fabry-Perot interference filter 10 configured as described above, when a voltage is applied to the first electrode 22 and the third electrode 24 via a plurality of terminals 25, 26, a potential difference is generated between the first electrode 22 and the third electrode 24, and an electrostatic force corresponding to this potential difference is generated between the first electrode 22 and the third electrode 24. The electrostatic force generated between the first electrode 22 and the third electrode 24 attracts the second mirror portion 36 to the first mirror portion 35, and the distance between the first mirror portion 35 and the second mirror portion 36 is adjusted. At this time, the second electrode 23, which is at the same potential as the third electrode 24, functions as a compensating electrode, and the second mirror portion 36 is kept flat in the light transmission region 10a. Thus, in the Fabry-Perot interference filter 10, the distance between the first mirror portion 35 and the second mirror portion 36 is variable. Here, the wavelength of light transmitted through the Fabry-Perot interference filter 10 depends on the distance between the first mirror portion 35 and the second mirror portion 36. Therefore, by adjusting the voltage applied to the first electrode 22 and the third electrode 24 (the potential difference generated between the first electrode 22 and the third electrode 24), the wavelength of light transmitted through the Fabry-Perot interference filter 10 can be selected. [Configuration of the spectroscopic module]

[0054] Referring to Figures 4 to 11, a spectral module in one embodiment to which the above-described spectral unit 1 is applied will be described. In Figures 5 and 6, the cover 63, which will be described later, is not shown. In Figure 8, the internal configuration of the spectral unit 1, as well as the light source 71 and fastening shaft member 81, which will be described later, are not shown. The spectral module 100 comprises the spectral unit 1, a package 60, a light source 71, a substrate 72, a substrate 73, a pair of fastening shaft members (first fastening shaft member) 81, a pair of fastening shaft members (second fastening shaft member) 82, a pair of fastening shaft members 83, and a fastening shaft member 84.

[0055] Package 60 houses the spectroscopic unit 1, light source 71, substrate 72 and substrate 73, etc. Package 60 may further house, for example, a wireless communication substrate or a battery case. Package 60 has, for example, a rectangular parallelepiped shape. Package 60 has a main body portion 61 to which the spectroscopic unit 1 is fixed, a cover portion 62 that covers the spectroscopic unit 1, and a lid 63 that covers the substrate 72 and substrate 73. The spectroscopic unit 1, light source 71, substrate 72 and substrate 73, etc. are arranged on the main body portion 61.

[0056] As shown in Figure 7, the main body 61 has a surface 61a and a surface 61b opposite to surface 61a. A recess 611 is formed in the main body 61. The recess 611 opens to surface 61a. A substrate 72 and a substrate 73 are arranged on the main body 61. The substrate 72 is positioned on the bottom surface 611a of the recess 611. The substrate 72 is positioned such that its surface 72a is flush with the surface 61a of the main body 61. The surface 72a of the substrate 72 does not have to be flush with the surface 61a of the main body 61, and may be positioned higher than the surface 61a (away from the main body 61). The substrate 73 is arranged so as to be stacked on the substrate 72 with a gap in direction A. The substrate 73 is positioned on the opposite side of the main body 61 from the substrate 72.

[0057] As shown in Figure 5, the substrate 72 is fixed to the main body 61 by a pair of fastening shaft members 83. The substrate 73 is fixed to the intermediate member 66, which will be described later, by a fastening shaft member 84. A fastening shaft member is an axial member used to fix parts together. The fastening shaft member 83 is an axial member that fixes the substrate 72 to the main body 61. In this example, the fastening shaft member 83 is a screw. The fastening shaft member 83 may be another fastening shaft member such as a bolt. The fastening shaft member 83 is inserted into a hole formed across the substrate 72 and the main body 61. A screw thread is formed in the hole formed across the substrate 72 and the main body 61. The substrate 72 is fixed to the main body 61 by screwing the fastening shaft member 83 into the hole formed across the substrate 72 and the main body 61.

[0058] The fastening shaft member 84 is a shaft-shaped member that fixes the base plate 73 to the intermediate member 66. In this example, the fastening shaft member 84 is a screw. The fastening shaft member 84 may be other fastening shaft members such as bolts. The fastening shaft member 84 is inserted into a hole formed across the base plate 73 and the intermediate member 66. A screw thread is formed in the hole formed across the base plate 73 and the intermediate member 66. The base plate 73 is fixed to the intermediate member 66 by screwing the fastening shaft member 84 into the hole formed across the base plate 73 and the intermediate member 66. Wiring (not shown) is formed inside or on the surface of the base plate 72 and the base plate 73.

[0059] As shown in Figure 7, the spectroscopic unit 1 and the light source 71 are arranged on the substrate 72. Multiple lead pins 11 of the spectroscopic unit 1 and multiple lead pins of the light source 71 are electrically connected to the substrate 72. Multiple through holes 721 are formed in the substrate 72. Each lead pin 11 is inserted into the corresponding through hole 721. The housing 2 of the spectroscopic unit 1 and the light source 71 are arranged adjacent to each other in a direction perpendicular to direction A. The spectroscopic unit 1 is placed on the surface 72a of the substrate 72 and fixed to the main body 61 via the substrate 72. More specifically, the housing 2 of the spectroscopic unit 1 is fixed to the substrate 72 by multiple lead pins 11 that penetrate the substrate 72 and are fixed to the substrate 72. The light source 71 emits light to irradiate the object to be measured. The light source 71 is, for example, an infrared lamp that emits light in the near-infrared to mid-infrared wavelength range. The light source 71 is fixed to the substrate 72 by a lead pin holder 71a that penetrates the substrate 72 and is fixed to the substrate 72, while being separated from the surface 72a of the substrate 72.

[0060] The cover portion 62 is positioned on the main body portion 61 and covers the spectral unit 1. The cover portion 62 has an aperture member 65 and an intermediate member 66. The intermediate member 66 is positioned between the main body portion 61 and the aperture member 65 in direction A. That is, in direction A, the main body portion 61, the intermediate member 66 and the aperture member 65 are stacked in this order.

[0061] The aperture member 65 has a surface 65a opposite to the main body 61 and a surface 65b on the main body 61 side. The aperture member 65 has a recess 651, a recess 652, and a hole 653 formed therein. The recess 651 opens to the surface 65a. A window portion 75, made of, for example, glass, is provided on the bottom surface 651a of the recess 651. In this example, the outer surface of the window portion 75 protrudes slightly from the surface 65a. The outer surface of the window portion 75 may be flush with the surface 65a. In the spectroscopic module 100, for example, with the outer surface of the window portion 75 in contact with the object, it is possible to irradiate the object with light and detect the light reflected by the object. Power to the spectroscopic module 100 is supplied via a general-purpose connector such as a USB (Universal Serial Bus) socket.

[0062] The recess 652 opens into the bottom surface 651a of the recess 651. The hole 653 opens into the bottom surface 651a of the recess 651 and the surface 65b of the aperture member 65. Inside the aperture member 65, the recess 652 and the hole 653 are connected to each other. That is, the recess 652 and the hole 653 form a single continuous space. The aperture member 65 has a wall portion 654 located between the bottom surface 652a and the surface 65b of the recess 652. An aperture 655 is formed in the wall portion 654, opening into the bottom surface 652a and the surface 65b. When viewed from direction A, the aperture 655 has a circular shape. The aperture 655 faces the opening 20 of the housing 2 in direction A.

[0063] The aperture member 65 has a positioning portion 656 formed thereon. The positioning portion 656 is used to position the cover portion 62 (aperture member 65) relative to the housing 2 during the manufacturing process of the spectroscopic module 100. The positioning portion 656 is a protrusion that projects from the surface 65b toward the main body portion 61. In a direction perpendicular to direction A, the positioning portion 656 is formed so as to sandwich the housing 2. "In a direction perpendicular to direction A, the positioning portion 656 is formed so as to sandwich the housing 2" means that in a direction perpendicular to direction A, the positioning portion 656 is located on both sides of the housing 2.

[0064] As shown in Figure 10, when viewed from direction A, the positioning portion 656 is formed continuously around the outer edge 2a of the housing 2. When viewed from direction A, the positioning portion 656 is formed in the shape of a circular frame. When viewed from direction A, the width of the inner edge 656a of the positioning portion 656 is greater than the width of the outer edge 2a of the housing 2. In this embodiment, the width of the inner edge 656a of the positioning portion 656 is the diameter of the circle defined by the inner edge 656a. The side wall 5 of the housing 2 is cylindrical, and the outer edge 2a of the housing 2 is circular. Therefore, the width of the outer edge 2a of the housing 2 is the diameter of the circle defined by the outer edge 2a.

[0065] Because the width of the inner edge 656a of the positioning portion 656 is greater than the width of the outer edge 2a of the housing 2, a gap (mechanical play) is formed between the positioning portion 656 and the housing 2. The width of the inner edge 656a of the positioning portion 656 may be 8.25 mm or more and 8.3 mm or less. The width of the outer edge 2a of the housing 2 may be 8.15 mm or more and 8.25 mm or less. The difference between the width of the inner edge 656a of the positioning portion 656 and the width of the outer edge 2a of the housing 2 (mechanical play between the positioning portion 656 and the housing 2) may be 0 mm or more and 0.15 mm or less. If the difference between the width of the inner edge 656a of the positioning portion 656 and the width of the outer edge 2a of the housing 2 is 0 mm, no gap is formed between the positioning portion 656 and the housing 2 (see Figure 12). In this case, the positioning portion 656 abuts against the housing 2. More specifically, the inner surface of the positioning portion 656 contacts the outer surface of the side wall 5 of the housing 2.

[0066] When the housing 2 is positioned inside the positioning section 656, the aperture 655 of the aperture member 65, the opening 20 of the housing 2, and the aperture 50 of the aperture section 51A (Figure 1) overlap (are aligned) with each other in direction A. When viewed from direction A, the opening 20 is larger than the apertures 655 and 50. A gap is formed between the surface 65b of the aperture member 65 and the surface of the housing 2 opposite to the main body 61 (outer surface 6b). In direction A, the width of the gap between the surface 65b and the outer surface 6b is smaller than the height of the positioning section 656. That is, with respect to the surface 65b, in direction A, the end face 656b of the positioning section 656 on the main body 61 side is located closer to the main body 61 than the outer surface 6b.

[0067] As shown in Figure 11, the aperture member 65 is adjacent to the lid 63 in a direction perpendicular to direction A. When viewed from direction A, the aperture member 65 has a protrusion 657 that projects toward the lid 63. The protrusion 657 is positioned to fit into a recess 633 formed in the lid 63, which will be described later.

[0068] As shown in Figure 7, the intermediate member 66 has a surface 66a opposite to the main body 61 and a surface 66b on the main body 61 side. Surface 66a is in contact with the surface 65b of the aperture member 65. Surface 66b is in contact with the surface 61a of the main body 61. If the surface 72a of the substrate 72 is located at a higher position (away from the main body 61) than the surface 61a of the main body 61, then surface 66b does not need to be in contact with surface 61a. The intermediate member 66 has recesses 661 and 662 formed therein. Recess 661 opens to the surface 66b of the intermediate member 66. Recess 662 opens to the surface 66a of the intermediate member 66. A positioning part 656 is located inside recess 662. In this example, no step is formed at the boundary between the inner surface of recess 662 and the hole 653 of the aperture member 65. A step may be formed at the boundary between the inner surface of the recess 662 and the hole 653 of the aperture member 65. The intermediate member 66 has a wall portion 663 located between the bottom surface 662a of the recess 662 and the bottom surface 661a of the recess 661. Holes 664 and 665 are formed in the wall portion 663. Holes 664 and 665 each open to the bottom surfaces 662a and 661a, respectively. When viewed from direction A, holes 664 and 665 each have a circular shape. The diameter of hole 664 is larger than the diameter of hole 665.

[0069] A space S1 is formed inside the cover portion 62. In this example, space S1 includes the spaces inside the recesses 651, 652, and 653 formed in the aperture member 65, and the recesses 661, 662, 664, and 665 formed in the intermediate member 66. In this example, the cover portion 62 (aperture member 65 and intermediate member 66) is made of a material containing aluminum. More specifically, the cover portion 62 is made of an aluminum alloy. Therefore, the inner surface of the cover portion 62 defining space S1 is made of a material containing aluminum (aluminum alloy). The inner surface of the cover portion 62 defining space S1 includes the inner surfaces of the recesses 651, 652, 653, 661, 662, 664, and 665.

[0070] The housing 2 and the light source 71 are housed in space S1. More specifically, the housing 2 is located inside recess 661, hole 664, and recess 662 in space S1. The entire housing 2 is located inside the intermediate member 66. In direction A, the surface 66a of the intermediate member 66 is further from the main body 61 than the surface (outer surface 6b) of the housing 2 opposite to the main body 61. In direction A, the height of the intermediate member 66 (surface 66a) relative to the surface 61a of the main body 61 is greater than the height of the housing 2 (outer surface 6b). The light source 71 is located inside recess 661, hole 665, and recess 662 in space S1. The entire light source 71 is located inside the intermediate member 66.

[0071] As shown in Figures 4 and 5, the lid 63 is attached to the main body 61 so as to cover the substrate 72 and the substrate 73. The lid 63 has a plate portion 631 that extends perpendicular to direction A, and a pair of side wall portions 632 that extend along direction A at the end of the plate portion 631. As shown in Figure 11, the lid 63 has a recess 633 that is recessed away from the aperture member 65 when viewed from direction A. When viewed from direction A, a gap (mechanical play) may be formed between the lid 63 and the aperture member 65 (for example, between the recess 633 and the protrusion 657).

[0072] Next, the manner in which the aperture member 65 is fixed to the intermediate member 66, and the manner in which the cover portion 62 (intermediate member 66) is fixed to the main body portion 61 will be described. The package 60 has a pair of holes (first holes) 91 and a pair of holes (second holes) 95. A corresponding fastening shaft member 81 from a pair of fastening shaft members 81 is inserted into each hole 91. A corresponding fastening shaft member 82 from a pair of fastening shaft members 82 is inserted into each hole 95.

[0073] Each hole 91 is formed along direction A, as shown in Figures 7 and 8. The axial direction of the fastening shaft member 81 inserted into each hole 91 is along direction A. Each hole 91 is composed of a counterbore 92 formed in the aperture member 65, a hole (first hole) 93 formed in the aperture member 65, and a hole (second hole) 94 formed in the intermediate member 66. In this example, the hole 91 is formed by the counterbore 92, the hole 93, and the hole 94. The counterbore 92 is a bottomed hole that opens on the surface 65a of the aperture member 65. The counterbore 92 has a bottom surface 92a. When viewed from direction A, the counterbore 92 has a circular shape. The head 811 of the fastening shaft member 81, which will be described later, is located inside the counterbore 92.

[0074] The hole 93 is a through hole that opens at the bottom surface 92a of the counterbore 92 and the surface 65b of the aperture member 65. The hole 93 is formed along direction A. When viewed from direction A, the hole 93 has a circular shape. The threaded portion 812 of the fastening shaft member 81, which will be described later, is located inside the hole 93. The hole 94 is a bottomed hole that opens at the surface 66a of the intermediate member 66. The hole 94 has a bottom surface 94a. The hole 94 is formed along direction A. When viewed from direction A, the hole 94 has a circular shape. The threaded portion 812 of the fastening shaft member 81 is located inside the hole 94. Threads (not shown) are formed on the inner surface of the hole 94. That is, the hole 94 is a female screw with helical threads. In contrast, no threads are formed on the inner surface of the hole 93.

[0075] Each fastening shaft member 81 is a shaft-shaped member that fixes the aperture member 65 to the intermediate member 66. In this example, the fastening shaft member 81 is a screw. The fastening shaft member 81 may be other fastening shaft members such as bolts. The fastening shaft member 81 is inserted into the hole 91 and fixes the aperture member 65 to the intermediate member 66. Each fastening shaft member 81 has a head 811 and a threaded portion 812. The head 811 is located at one end of the fastening shaft member 81 and is a part for rotating the fastening shaft member 81 using a tool or the like (for example, a part in which a groove is formed into which a tool or the like is fitted). The threaded portion 812 is a part in which a screw thread (not shown) is formed. The fastening shaft member 81 is a male screw with a helical screw thread formed thereon. The threaded portion 812 bites into the target part to be fixed (in this example, the intermediate member 66) when the fastening shaft member 81 is rotated. By rotating the fastening shaft member 81, the threaded portion 812 is screwed into the hole 94 and fixed in place. With the fastening shaft member 81 inserted into the hole 91, the head portion 811 is positioned in the counterbore portion 92, biasing the aperture member 65 against the intermediate member 66. As a result, the aperture member 65 is fixed to the intermediate member 66 by the fastening shaft member 81.

[0076] The hole 93 is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member 81 (threaded portion 812) in a cross section perpendicular to the axial direction of the fastening shaft member 81. In contrast, the hole 94 has an inner edge that substantially coincides with the outer edge of the fastening shaft member 81 (threaded portion 812) in a cross section perpendicular to the axial direction of the fastening shaft member 81. In a direction perpendicular to the axial direction of the fastening shaft member 81, the hole 93 has a width W1 and the hole 94 has a width W2. In this example, width W1 is the diameter of the hole 93 when viewed from the axial direction of the fastening shaft member 81. Width W2 is the diameter of the hole 94 when viewed from the axial direction of the fastening shaft member 81. In this embodiment, width W2 is the diameter of the circle defined by the vertices of the threads in the hole 94 when viewed from the axial direction of the fastening shaft member 81. In a direction perpendicular to the axial direction of the fastening shaft member 81, the fastening shaft member 81 has a width W3. In this embodiment, the width W3 is the diameter of the circle defined by the vertices of the threads of the fastening shaft member 81 when viewed from the axial direction of the fastening shaft member 81.

[0077] The width W1 of the hole 93 is greater than the width W2 of the hole 94. The width W1 of the hole 93 is greater than the width W3 of the fastening shaft member 81. In this example, the width W1 of the hole 93 is greater than the width W3 of the fastening shaft member 81 by at least 30% of the width W3. The width W1 of the hole 93 may be greater than the width W3 of the fastening shaft member 81 by at least 10% of the width W3. Because the width W1 of the hole 93 is greater than the width W3 of the fastening shaft member 81, a gap (mechanical play) is formed between the fastening shaft member 81 and the hole 93. In this example, the width W1 of the hole 93 is 2.6 mm or more and 2.7 mm or less. The width W1 of the hole 93 may be, for example, 2.2 mm or more and 4.5 mm or less. The lower limit of the width W1 may be greater than the width W3 of the fastening shaft member 81 by at least 10% of the width W3. The upper limit of the width W1 may be determined based on the standard head diameter of the fastening shaft member 81 (screw). In this example, the width W3 of the fastening shaft member 81 is 2 mm. In this example, the difference between the width W1 of the hole 93 and the width W3 of the fastening shaft member 81 (mechanical play between the hole 93 and the fastening shaft member 81) is 0.6 mm or more and 0.7 mm or less. The difference between the width W1 of the hole 93 and the width W3 of the fastening shaft member 81 is greater than the difference between the width of the inner edge 656a of the positioning part 656 and the width of the outer edge 2a of the housing 2. In this example, the width W3 of the fastening shaft member 81 is assumed to be 2 mm, but the width W3 may be 3 mm or 4 mm.

[0078] As described above, each lead pin 11 is inserted into a corresponding through-hole 721 among a plurality of through-holes 721 formed in the substrate 72. The lead pins 11 are fixed to the substrate 72 using solder (not shown). The lead pins 11 are formed in a cylindrical shape. When viewed from direction A, the lead pins 11 have a circular shape. When viewed from direction A, the through-holes 721 have a circular shape. In a direction perpendicular to direction A, the width (diameter) of the through-holes 721 is greater than the width (diameter) of the lead pins 11. As a result, a gap (mechanical play) is formed between the lead pins 11 and the through-holes 721. In this example, the width of the through-holes 721 is 1 mm or less, and the width of the lead pins 11 is 0.45 mm. The difference between the width of the through-holes 721 and the width of the lead pins 11 (mechanical play between the through-holes 721 and the lead pins 11) is 0.55 mm or less. The difference between the width W1 of the hole 93 and the width W3 of the fastening shaft member 81 is greater than the difference between the width of the through-hole 721 and the width of the lead pin 11.

[0079] Each hole 95 is formed along direction A, as shown in Figure 9. The axial direction of the fastening shaft member 82 inserted into each hole 95 is along direction A. Each hole 95 is composed of a counterbore 96 formed in the main body 61, a hole (third hole) 97 formed in the main body 61, a hole 98 formed in the substrate 72, and a hole (fourth hole) 99 formed in the intermediate member 66 (cover 62). In this example, the hole 95 is formed by the counterbore 96, the hole 97, the hole 98, and the hole 99. The counterbore 96 is a bottomed hole that opens on the surface 61b of the main body 61. The counterbore 96 has a bottom surface 96a. When viewed from direction A, the counterbore 96 has a circular shape. The head 821 of the fastening shaft member 82, which will be described later, is located inside the counterbore 96.

[0080] The hole 97 is a through hole that opens at the bottom surface 96a of the counterbore 96 and the bottom surface 611a of the recess 611. The hole 97 is formed along direction A. When viewed from direction A, the hole 97 has a circular shape. The threaded portion 822 of the fastening shaft member 82, which will be described later, is located inside the hole 97. The hole 98 is a through hole that opens at the surface 72b of the substrate 72 and the surface 72a of the substrate 72. The hole 98 is formed along direction A. When viewed from direction A, the hole 98 has a circular shape. The threaded portion 822 of the fastening shaft member 82 is located inside the hole 98. The hole 99 is a through hole that opens at the surface 66b of the intermediate member 66 and the surface 66a of the intermediate member 66. The hole 99 is formed along direction A. When viewed from direction A, the hole 99 has a circular shape. The threaded portion 822 of the fastening shaft member 82 is positioned inside the hole 99. Threads (not shown) are formed on the inner surface of the hole 99. In other words, the hole 99 is a female thread with a helical thread. In contrast, no threads are formed on the inner surfaces of the holes 97 and 98.

[0081] Each fastening shaft member 82 is a shaft-shaped member that fixes the intermediate member 66 (cover portion 62) to the main body portion 61. In this example, the fastening shaft member 82 is a screw. The fastening shaft member 82 may be other fastening shaft members such as bolts. The fastening shaft member 82 is inserted into the hole 95 and fixes the main body portion 61 to the intermediate member 66. Each fastening shaft member 82 has a head 821 and a threaded portion 822. The head 821 is located at one end of the fastening shaft member 82 and is a part for rotating the fastening shaft member 82 using a tool or the like (for example, a part in which a groove into which a tool or the like is fitted is formed). The threaded portion 822 is a part in which a screw thread (not shown) is formed. The fastening shaft member 82 is a male screw with a helical screw thread formed thereon. The threaded portion 822 bites into the target part to be fixed (in this example, the intermediate member 66) by rotating the fastening shaft member 82. By rotating the fastening shaft member 82, the threaded portion 822 is screwed into the hole 99 and fixed in place. With the fastening shaft member 82 inserted into the hole 95, the head portion 821 is positioned in the counterbore portion 96, biasing the main body portion 61 against the intermediate member 66. As a result, the intermediate member 66 (cover portion 62) is fixed to the main body portion 61 by the fastening shaft member 82.

[0082] The hole 97 is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member 82 (threaded portion 822) in a cross-section perpendicular to the axial direction of the fastening shaft member 82. In contrast, the hole 99 has an inner edge that substantially coincides with the outer edge of the fastening shaft member 82 (threaded portion 822) in a cross-section perpendicular to the axial direction of the fastening shaft member 82. In a direction perpendicular to the axial direction of the fastening shaft member 82, the hole 97 has a width W4 and the hole 99 has a width W5. In this example, width W4 is the diameter of the hole 97 when viewed from the axial direction of the fastening shaft member 82. Width W5 is the diameter of the hole 99 when viewed from the axial direction of the fastening shaft member 82. In this embodiment, width W5 is the diameter of the circle defined by the vertices of the threads in the hole 99 when viewed from the axial direction of the fastening shaft member 82. In a direction perpendicular to the axial direction of the fastening shaft member 82, the fastening shaft member 82 has a width W6. In this embodiment, the width W6 is the diameter of the circle defined by the vertices of the threads of the fastening shaft member 82 when viewed from the axial direction of the fastening shaft member 82.

[0083] The width W4 of the hole 97 is greater than the width W5 of the hole 99. The width W4 of the hole 97 is greater than the width W6 of the fastening shaft member 82. In this example, the width W4 of the hole 97 is greater than the width W6 of the fastening shaft member 82 by at least 10% of the width W6. The width W4 of the hole 97 may also be greater than the width W6 of the fastening shaft member 82 by at least 30% of the width W6. Because the width W4 of the hole 97 is greater than the width W6 of the fastening shaft member 82, a gap (mechanical play) is formed between the fastening shaft member 82 and the hole 97. In this example, the width W4 of the hole 97 is 2.2 mm or more and 2.4 mm or less. The width W4 of the hole 97 may also be, for example, 2.2 mm or more and 4.5 mm or less. The lower limit of the width W4 may be greater than the width W6 of the fastening shaft member 82 by at least 10% of the width W6. The upper limit of the width W4 may be determined based on the standard head diameter of the fastening shaft member 82 (screw). In this example, the width W6 of the fastening shaft member 82 is 2 mm. In this example, the difference between the width W4 of the hole 97 and the width W6 of the fastening shaft member 82 (mechanical play between the hole 97 and the fastening shaft member 82) is 0.2 mm or more and 0.4 mm or less. The difference between the width W4 of the hole 97 and the width W6 of the fastening shaft member 82 is greater than the difference between the width of the inner edge 656a of the positioning part 656 and the width of the outer edge 2a of the housing 2. In this example, the width W6 of the fastening shaft member 82 is assumed to be 2 mm, but the width W6 may be 3 mm or 4 mm. [Manufacturing method of spectroscopic module]

[0084] The manufacturing method for the spectroscopic module 100 described above will now be explained. First, a main body 61 on which the spectroscopic unit 1 and light source 71 are arranged is prepared. At this time, the spectroscopic unit 1 and light source 71 are placed on the main body 61 via a substrate 72. In this example, the spectroscopic unit 1 and light source 71 are placed on the main body 61 in a state where they are fixed to the substrate 72.

[0085] Next, the cover portion 62 (aperture member 65 and intermediate member 66) is placed on the main body portion 61 so as to cover the spectroscopic unit 1. The cover portion 62 (aperture member 65 and intermediate member 66) is placed on the main body portion 61 so as to be positioned between the main body portion 61 and the aperture member 65. Specifically, first, the intermediate member 66 is placed on the main body portion 61 so as to pass the housing 2 through the hole 664 and the light source 71 through the hole 665. Next, the aperture member 65 is placed on the intermediate member 66. At this time, the positioning unit 656 positions the aperture member 65 relative to the housing 2 (spectroscopic module 100). Specifically, the aperture member 65 is placed on the intermediate member 66 so as to be positioned inside the positioning unit 656. The steps of placing the cover portion 62 on the main body portion 61 and positioning the aperture member 65 relative to the housing 2 may be performed simultaneously, or the step of positioning the aperture member 65 relative to the housing 2 may be performed after the step of placing the cover portion 62 on the main body portion 61. Next, the substrate 73 is placed on a part of the intermediate member 66 so as to be stacked with a gap between it and the substrate 72.

[0086] In this state, the fastening shaft members are inserted into the corresponding holes. Specifically, a pair of fastening shaft members 81 are inserted into a pair of holes 91. At this time, the fastening shaft members 81 are loosely tightened to the extent that the intermediate member 66 and the aperture member 65 can be aligned (to the extent that their positions can be moved slightly). Similarly, a pair of fastening shaft members 82 are inserted into a pair of holes 95. At this time, the fastening shaft members 82 are loosely tightened to the extent that the main body 61 and the intermediate member 66 (cover 62) can be aligned. Similarly, a pair of fastening shaft members 83 are inserted into a pair of holes formed across the substrate 72 and the main body 61. At this time, the fastening shaft members 83 are loosely tightened to the extent that the main body 61 and the substrate 72 can be aligned. Similarly, a fastening shaft member 84 is inserted into a hole formed across the substrate 73 and the intermediate member 66. At this time, the fastening shaft member 84 is loosely tightened to the extent that the substrate 73 and the intermediate member 66 can be aligned.

[0087] Next, with the aperture member 65 positioned relative to the housing 2 by the positioning unit 656, the aperture member 65 is fixed to the intermediate member 66 by the fastening shaft member 81. Specifically, with the housing 2 positioned inside the positioning unit 656, the aperture member 65 is aligned so that the aperture 655 of the aperture member 65 and the opening 20 of the housing 2 overlap each other in direction A, thereby achieving a more precise positioning of the aperture member 65. At this time, the aperture member 65 and the intermediate member 66 are positioned relative to each other so that the inner surface of the aperture member 65 and the inner surface of the intermediate member 66 are aligned. Specifically, the aperture member 65 and the intermediate member 66 are positioned so that no step is formed at the boundary between the inner surface of the hole 653 of the aperture member 65 and the inner surface of the recess 662 of the intermediate member 66.

[0088] Next, the aperture member 65 is fixed to the intermediate member 66 by the fastening shaft member 81 inserted into the hole 91. By rotating the fastening shaft member 81 using a tool or the like, the threaded portion 812 of the fastening shaft member 81 is screwed into the hole 94 of the hole 91 (engaging the threads together). The fastening shaft member 81 is tightened to the extent that the positions of the intermediate member 66 and the aperture member 65 do not shift relative to each other. As a result, the aperture member 65 is fixed to the intermediate member 66 by the fastening shaft member 81.

[0089] Next, the substrate 73 is fixed to the intermediate member 66 by a fastening shaft member 84 inserted into a hole formed across the substrate 73 and the intermediate member 66. By rotating the fastening shaft member 84 using a tool or the like, the threaded portion of the fastening shaft member 84 is screwed into the hole formed across the substrate 73 and the intermediate member 66 (engaging the threads together). The fastening shaft member 84 is tightened to the extent that the positions of the substrate 73 and the intermediate member 66 do not shift relative to each other. As a result, the substrate 73 is fixed to the intermediate member 66 by the fastening shaft member 84.

[0090] Next, the intermediate member 66 is fixed to the main body 61 by the fastening shaft member 82 inserted into the hole 95. By rotating the fastening shaft member 82 using a tool or the like, the threaded portion 822 of the fastening shaft member 82 is screwed into the hole 99 of the hole 95 (engaging the threads together). The fastening shaft member 82 is tightened to the extent that the positions of the main body 61 and the intermediate member 66 (cover portion 62) do not shift relative to each other. As a result, the intermediate member 66 (cover portion 62) is fixed to the main body 61 by the fastening shaft member 82. At this time, the intermediate member 66 and the main body 61 are positioned relative to each other so that the side surface (outer surface) of the intermediate member 66 and the side surface (outer surface) of the main body 61 are aligned.

[0091] Next, the substrate 72 is fixed to the main body 61 by a fastening shaft member 83 inserted into a hole formed across the substrate 72 and the main body 61. By rotating the fastening shaft member 83 using a tool or the like, the threaded portion of the fastening shaft member 83 is screwed into the hole formed across the substrate 72 and the main body 61 (engaging the threads together). The fastening shaft member 83 is tightened to the extent that the positions of the substrate 72 and the main body 61 do not shift relative to each other. As a result, the substrate 72 is fixed to the main body 61 by the fastening shaft member 83. In addition, the spectral unit 1 and the light source 71 are fixed to the main body 61 via the substrate 72.

[0092] Next, the lid 63 is attached to the main body 61. Through the above process, the spectroscopic module 100 is manufactured. Depending on the measurement method of the spectroscopic module 100, other attachments (other aperture members) may be attached in place of the aperture member 65. In this case, the aperture member 65 may be removed by rotating and loosening the fastening shaft member 81. [Operation and Effects]

[0093] In the spectroscopic module 100, the aperture member 65 of the cover portion 62 has an aperture 655 facing the opening 20 of the housing 2 in direction A, and a positioning portion 656 for positioning the aperture member 65 relative to the housing 2. The positioning portion 656 allows for easy and accurate alignment of the aperture 655 of the aperture member 65 with the opening 20 of the housing 2. This ensures that signal light from the object to be measured is reliably incident on the Fabry-Perot interference filter 10 through the aperture 655 and the opening 20 of the housing 2. Furthermore, a fastening shaft member 81 is inserted into a hole 91 which includes a hole 93 formed in the aperture member 65 and a hole 94 formed in the intermediate member 66. The hole 93 is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member 81 in a cross section perpendicular to the axial direction of the fastening shaft member 81. As a result, when the fastening shaft member 81 is inserted into the hole 91, the relative position of the aperture member 65 and the intermediate member 66 can move in a direction perpendicular to direction A. Therefore, when the aperture member 65 is fixed to the intermediate member 66 by the fastening shaft member 81, even if the positioning part 656 comes into contact with the housing 2, excessive stress is not applied to the spectroscopic unit 1, and displacement, damage, etc., of the spectroscopic unit 1 can be suppressed. Similarly, the fastening shaft member 82 is inserted into a hole 95 which is composed of a hole 97 formed in the main body 61 and a hole 99 formed in the intermediate member 66. The hole 97 is an enlarged hole having an inner edge that is larger than the outer edge of the fastening shaft member 82 in a cross section perpendicular to the axial direction of the fastening shaft member 82. As a result, when the fastening shaft member 82 is inserted into the hole 95, the relative position of the main body 61 and the intermediate member 66 can move in a direction perpendicular to direction A. Therefore, when the intermediate member 66 is fixed to the main body 61 by the fastening shaft member 82, even if the positioning part 656 comes into contact with the housing 2, excessive stress is not applied to the spectroscopic unit 1, and displacement, damage, etc. of the spectroscopic unit 1 can be suppressed. Thus, the spectroscopic module 100 can improve measurement performance.

[0094] In a direction perpendicular to direction A, the positioning portion 656 is formed to sandwich the housing 2. This makes it easier and more accurate to align the aperture 655 of the cover portion 62 with the opening 20 of the housing 2.

[0095] When viewed from direction A, the positioning portion 656 is formed continuously so as to surround the outer edge 2a of the housing 2. This makes it easier and more accurate to align the aperture 655 of the cover portion 62 with the opening 20 of the housing 2.

[0096] The spectroscopic module 100 includes a substrate 72 housed in a package 60. The spectroscopic unit 1 is placed on the substrate 72 and fixed to the main body 61 via the substrate 72. This allows for alignment between the cover portion 62 (aperture member 65) and the housing 2 of the spectroscopic unit 1 in a stable state with the spectroscopic unit 1 mounted on the substrate 72.

[0097] The spectroscopic module 100 is equipped with a light source 71 that emits light. The housing 2 and the light source 71 are arranged adjacent to each other. This allows the spectroscopic module 100 to be used as a reflective spectroscopic module.

[0098] A space S1 for housing the housing 2 is formed inside the cover portion 62. The inner surface of the cover portion 62 defining the space S1 is made of a material containing aluminum (aluminum alloy). This makes it possible to improve the utilization efficiency of the signal light incident on the spectroscopic module 100 and improve the signal-to-noise ratio, for example, when the spectroscopic module 100 is used as a reflective spectroscopic module.

[0099] In direction A, the surface 66a of the intermediate member 66 opposite to the main body 61 is further away from the main body 61 than the surface (outer surface 6b) of the housing 2 opposite to the main body 61. This allows the housing 2 to be protected by the intermediate member 66 when, for example, the diameter of the aperture 655 is changed, or when the aperture member 65 is changed (removed) to guide signal light through an optical fiber from the outside, the taller intermediate member 66 remains.

[0100] In a direction perpendicular to the axial direction of the fastening shaft member 81, the width W1 of the hole 93 (enlarged hole) is greater than the width W3 of the fastening shaft member 81 by a length of at least 30% of the width W3. This ensures that the relative positional movement between the aperture member 65 and the intermediate member 66 is more reliable, thereby further suppressing misalignment, damage, etc., of the spectroscopic unit 1. As a result, measurement performance can be further improved.

[0101] This disclosure is not limited to the embodiments described above. Modifications of the embodiments described above are described below. The following description will primarily focus on the differences from the embodiments described above, and may omit explanations of commonalities.

[0102] The configuration of the positioning portion 656 is not limited to the configuration according to the embodiment described above. For example, the positioning portion 656 may have the shape shown in Figures 13 to 19. Figures 13 to 19 are schematic diagrams showing cross-sections of the positioning portion 656 of each modified example when viewed from direction A. In the example shown in Figure 13, the positioning portion 656 is formed in the shape of a rectangular frame when viewed from direction A. When viewed from direction A, the positioning portion 656 is formed continuously so as to surround the outer edge 2a of the housing 2. The positioning portion 656 has a pair of first portions 671 extending parallel to each other and a pair of second portions 672 extending parallel to each other. The first portions 671 and the second portions 672 are orthogonal to each other. In a direction perpendicular to direction A, the positioning portion 656 is formed so as to sandwich the housing 2. The pair of first portions 671 are positioned so as to sandwich the housing 2 in one direction perpendicular to direction A. A pair of second portions 672 are positioned to sandwich the housing 2 in another direction perpendicular to direction A. The positioning portion 656 is in contact with the housing 2. The inner surface of the positioning portion 656 is in contact with the outer surface of the side wall 5 of the housing 2. In this example, the aperture member 65 (cover portion 62) is positioned relative to the housing 2 by arranging the aperture member 65 (cover portion 62) so that the housing 2 is positioned inside the rectangular frame-shaped positioning portion 656. A gap may be formed between the positioning portion 656 and the housing 2.

[0103] When viewed from direction A, the positioning portion 656 may be formed discontinuously. In the example shown in Figure 14, the positioning portion 656 is composed of a plurality (four in this example) of protrusions 673. When viewed from direction A, the plurality of protrusions 673 are spaced apart from each other so as to surround the outer edge 2a of the housing 2. When viewed from direction A, the plurality of protrusions 673 are located on the vertices of a rectangle. In a direction perpendicular to direction A, a pair of protrusions 673 located on the diagonals of the rectangle are positioned so as to sandwich the housing 2. The protrusions 673 have a cylindrical shape. The positioning portion 656 is in contact with the housing 2. Each protrusion 673 is in contact with the outer surface of the side wall 5 of the housing 2. In this example, the aperture member 65 (cover portion 62) is positioned relative to the housing 2 by arranging the aperture member 65 (cover portion 62) so as to position the housing 2 inside the four protrusions 673. The positioning portion 656 contacts the housing 2, making it easier and more accurate to align the aperture 655 of the cover portion 62 with the opening 20 of the housing 2. A gap may be formed between the positioning portion 656 (each protrusion 673) and the housing 2.

[0104] In the example shown in Figure 15, the positioning portion 656 is configured to include a pair of protrusions 673. The configuration of each protrusion 673 is the same as in the example shown in Figure 14. The pair of protrusions 673 are arranged side by side in a direction perpendicular to direction A. The positioning portion 656 is in contact with the housing 2. Each protrusion 673 is in contact with the outer surface of the side wall 5 of the housing 2. In this example, the aperture member 65 (cover portion 62) is positioned relative to the housing 2 by arranging the aperture member 65 (cover portion 62) so that the housing 2 is in contact with both of the pair of protrusions 673.

[0105] In the example shown in Figure 16, the positioning portion 656 is configured to include a pair of portions 674. When viewed from direction A, the pair of portions 674 are formed to surround the outer edge 2a of the housing 2. Each portion 674 is a convex portion that extends in an arc along the outer edge 2a of the housing 2 when viewed from direction A. In a direction perpendicular to direction A, the pair of portions 674 are positioned to sandwich the housing 2. Each portion 674 has an inner surface 674a that curves along the outer edge 2a of the housing 2 when viewed from direction A. The positioning portion 656 is in contact with the housing 2. The inner surface 674a of each portion 674 is in contact with the outer surface of the side wall 5 of the housing 2. In this example, the aperture member 65 (cover portion 62) is positioned relative to the housing 2 by arranging the aperture member 65 (cover portion 62) so that the housing 2 is positioned between the pair of portions 674. A gap may be formed between the positioning portion 656 (each portion 674) and the housing 2.

[0106] In the example shown in Figure 17, the positioning portion 656 is configured to include one portion 674. The configuration of portion 674 is the same as in the example shown in Figure 16. The positioning portion 656 is in contact with the housing 2. The inner surface 674a of portion 674 is in contact with the outer surface of the side wall 5 of the housing 2. In this example, the aperture member 65 (cover portion 62) is positioned relative to the housing 2 by arranging the aperture member 65 (cover portion 62) so that the housing 2 is in contact with the inner surface 674a of one portion 674.

[0107] In the example shown in Figure 18, the positioning portion 656 is configured to include a pair of portions 675. When viewed from direction A, the pair of portions 675 are formed to surround the outer edge 2a of the housing 2. Each portion 675 is a protruding portion that extends in an L-shape when viewed from direction A. In a direction perpendicular to direction A, the pair of portions 675 are positioned to sandwich the housing 2. Each portion 675 has an inner surface 675a ​​that extends in an L-shape when viewed from direction A. The positioning portion 656 is in contact with the housing 2. The inner surface 675a ​​of each portion 675 is in contact with the outer surface of the side wall 5 of the housing 2. In this example, the aperture member 65 (cover portion 62) is positioned relative to the housing 2 by arranging the aperture member 65 (cover portion 62) so that the housing 2 is positioned between the pair of portions 675. A gap may be formed between the positioning portion 656 (each portion 675) and the housing 2.

[0108] In the example shown in Figure 19, the positioning portion 656 is configured to include one portion 675. The configuration of portion 675 is the same as in the example shown in Figure 18. The positioning portion 656 is in contact with the housing 2. The inner surface 675a ​​of portion 675 is in contact with the outer surface of the side wall 5 of the housing 2. In this example, the aperture member 65 (cover portion 62) is positioned relative to the housing 2 by arranging the aperture member 65 (cover portion 62) so that the housing 2 is in contact with the inner surface 675a ​​of one portion 675.

[0109] In the hole 91, the hole portion 94 may be an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member 81 (threaded portion 812) in a cross section perpendicular to the axial direction of the fastening shaft member 81. The width (size) of the hole portion 94 may be the same as the width (size) of the hole portion 93 in the above embodiment. In this case, the hole portion 93 may have an inner edge that substantially coincides with the outer edge of the fastening shaft member 81 (threaded portion 812) in a cross section perpendicular to the axial direction of the fastening shaft member 81. In this case, a counterbore portion may be formed on the hole portion 94 side where the head portion 811 of the fastening shaft member 81 is positioned. The fastening shaft member 81 may be inserted into the hole 91 from the hole portion 94 side toward the hole portion 93 side.

[0110] In the hole 95, the hole portion 99 may be an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member 82 (threaded portion 822) in a cross section perpendicular to the axial direction of the fastening shaft member 82. The width (size) of the hole portion 99 may be the same as the width (size) of the hole portion 97 in the above embodiment. In this case, the hole portion 97 may have an inner edge that substantially coincides with the outer edge of the fastening shaft member 82 (threaded portion 822) in a cross section perpendicular to the axial direction of the fastening shaft member 82. In this case, a counterbore portion may be formed on the hole portion 99 side where the head portion 821 of the fastening shaft member 82 is positioned. The fastening shaft member 82 may be inserted into the hole 95 from the hole portion 99 side toward the hole portion 97 side.

[0111] The material of the cover portion 62 (aperture member 65 and intermediate member 66) is not limited to an aluminum alloy. The cover portion 62 may be formed from a material containing at least one of aluminum, silver, and gold. That is, the inner surface of the cover portion 62 defining the space S1 may be formed from a material containing at least one of aluminum, silver, and gold. The inner surface of the cover portion 62 defining the space S1 may be formed from a material containing at least one of aluminum, silver, and gold, while other parts of the cover portion 62 may be formed from a material other than the material containing at least one of aluminum, silver, and gold (for example, a metal or resin material that can be plated, vapor-deposited, or sputtered). In this case, in the cover portion 62 formed from a material other than the material containing at least one of aluminum, silver, and gold, the inner surfaces of the recesses 651, 652, 653, 661, 662, 664, and 665 (the inner surface of the cover portion 62 defining the space S1) may be plated with a material containing at least one of aluminum, silver, and gold. Furthermore, the inner surface of the cover portion 62 defining the space S1 may be coated not only by plating, but also by vapor deposition or sputtering. When a resin material is used as the material for the cover portion 62, it is preferable to use a conductive resin material for noise suppression, from the viewpoint of shielding the spectroscopic module 100 that is housed within it.

[0112] A protective film may be formed on the inner surface of the cover portion 62 that defines the space S1. The protective film may be a thin film having a thickness of several tens of nanometers to several hundred nanometers. The protective film does not have an optical effect on the light incident on the spectroscopic module 100. The protective film having no optical effect means that its light transmittance to incident light is 70% or more. When a protective film that does not have an optical effect is formed on the inner surface of the cover portion 62, "the inner surface of the cover portion 62 that defines the space" refers not to the surface of the protective film, but to the inner surface of the cover portion 62 itself (the surface on which light transmitted through the protective film is reflected). The protective film may, for example, be a film to prevent corrosion of the cover portion 62.

[0113] The width of the enlarged hole (width W1 of hole 93 and width W4 of hole 97) may be designed based on various tolerances set during the manufacturing process of the spectroscopic module 100. Specifically, the width of the enlarged hole may be designed based on tolerances for the position of the spectroscopic unit 1 relative to the substrate 72, tolerances for the position of hole 93 in the aperture member 65, tolerances for the position of hole 98 in the substrate 72, etc. The tolerance for the position of the spectroscopic unit 1 relative to the substrate 72 may be the sum of the tolerance for the position of the through-hole 721 in the substrate 72 and the tolerance for the width of the through-hole 721.

[0114] As an example, the width of the enlarged hole may be greater than the width of the fastening shaft member (width W3 of fastening shaft member 81 and width W6 of fastening shaft member 82) by a predetermined length greater than twice the sum of the maximum tolerance of the position of the spectroscopic unit 1 relative to the substrate 72 and the maximum tolerance of the position of the hole 93 in the aperture member 65. As another example, the width of the enlarged hole may be greater than the width of the fastening shaft member by a predetermined length greater than twice the maximum tolerance of the position of the hole 98 in the substrate 72. As yet another example, the width of the enlarged hole may be greater than the width of the fastening shaft member by a predetermined length greater than twice the sum of the maximum tolerance of the position of the spectroscopic unit 1 relative to the substrate 72, the maximum tolerance of the position of the hole 93 in the aperture member 65, and the maximum tolerance of the position of the hole 98 in the substrate 72.

[0115] Each of the above examples will be explained using specific numerical values. For example, when the tolerance for the position of the spectral unit 1 relative to the substrate 72 is ±0.2 mm, the maximum value of the tolerance for the position of the spectral unit 1 relative to the substrate 72 is 0.2 mm. When the tolerance for the position of the hole 93 in the aperture member 65 is ±0.1 mm, the maximum value of the tolerance for the position of the hole 93 in the aperture member 65 is 0.1 mm. When the tolerance for the position of the hole 98 in the substrate 72 is ±0.1 mm, the maximum value of the tolerance for the position of the hole 98 in the substrate 72 is 0.1 mm.

[0116] Based on these values, the sum of the maximum tolerance for the position of the spectral unit 1 relative to the substrate 72 and the maximum tolerance for the position of the hole 93 in the aperture member 65 (0.3 mm), doubled, is 0.6 mm. Therefore, the width of the enlarged hole (width W1 of hole 93 and width W4 of hole 97) may be greater than the width of the fastening shaft member (width W3 of fastening shaft member 81 and width W6 of fastening shaft member 82) by a predetermined length greater than 0.6 mm. In other words, the difference between the width of the enlarged hole and the width of the fastening shaft member (mechanical play between the enlarged hole and the fastening shaft member) may be greater than 0.6 mm.

[0117] Furthermore, twice the maximum tolerance value (0.1 mm) for the position of the hole 98 in the substrate 72 is 0.2 mm. The width of the enlarged hole may be greater than the width of the fastening shaft member by a predetermined length greater than 0.2 mm. In other words, the difference between the width of the enlarged hole and the width of the fastening shaft member may be greater than 0.2 mm.

[0118] Furthermore, the sum of the maximum tolerance for the position of the spectral unit 1 relative to the substrate 72, the maximum tolerance for the position of the hole 93 in the aperture member 65, and the maximum tolerance for the position of the hole 98 in the substrate 72 (0.4 mm), doubled, is 0.8 mm. The width of the enlarged hole may be greater than the width of the fastening shaft member by a predetermined length greater than 0.8 mm. In other words, the difference between the width of the enlarged hole and the width of the fastening shaft member may be greater than 0.8 mm.

[0119] The cover portion 62 may be formed as a single component. That is, the aperture member 65 and the intermediate member 66 may be formed integrally with each other. The cover portion 62 may have a portion corresponding to the aperture member 65 having an aperture 655 and a positioning portion 656, and a portion corresponding to the intermediate member 66 which is integrally formed with the portion corresponding to the aperture member 65.

[0120] The spectroscopic module 100 does not necessarily have a light source 71. In this case, light may be irradiated onto the object to be measured from a light source located outside the spectroscopic module 100, and the spectroscopic module 100 may detect the signal light from the object to be measured. In direction A, the surface 66a of the intermediate member 66 opposite to the main body 61 may be located closer to the main body 61 than the surface (outer surface 6b) of the housing 2 opposite to the main body 61. In direction A, a part of the housing 2 (the part on the top wall 6 side) may protrude from the surface 66a of the intermediate member 66.

[0121] 1...Spectroscopic unit, 2...Housing, 2a...Outer edge, 6b...Outer surface, 10...Fabry-Perot interference filter, 20...Aperture, 60...Package, 61...Main body, 62...Cover, 65...Aperture member, 66...Intermediate member, 66a...Surface, 71...Light source, 72...Substrate, 81...Fastening shaft member (first fastening shaft member), 82...Fastening shaft member (second fastening shaft member), 91...Hole (first hole), 93...Hole section (first hole section, enlarged hole section), 94...Hole section (second hole section), 95...Hole (second hole), 97...Hole section (third hole section, enlarged hole section), 99...Hole section (fourth hole section), 100...Spectroscopic module, 655...Aperture, 656...Positioning section, S1...Space.

Claims

1. A spectroscopic module comprising: a spectroscopic unit having a Fabry-Perot interference filter including a pair of mirror portions whose distance from each other is variable; a housing having an opening facing the Fabry-Perot interference filter in the opposing direction of the pair of mirror portions and housing the Fabry-Perot interference filter; a package housing the spectroscopic unit having a main body portion to which the spectroscopic unit is fixed; and a cover portion covering the spectroscopic unit; and a fastening shaft member inserted into a hole formed including a hole formed in the main body portion and a hole formed in the cover portion, and fixing the cover portion to the main body portion, wherein the cover portion has an aperture facing the opening in the opposing direction of the pair of mirror portions and a positioning portion for positioning the cover portion relative to the housing; and the hole formed in the main body portion or the hole formed in the cover portion is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member.

2. A spectroscopic unit comprising: a Fabry-Perot interference filter including a pair of mirror portions whose distance from each other is variable; a housing having an opening facing the Fabry-Perot interference filter in the opposing direction of the pair of mirror portions and housing the Fabry-Perot interference filter; a package housing the spectroscopic unit comprising: a main body portion to which the spectroscopic unit is fixed; a cover portion covering the spectroscopic unit; and a fastening shaft member inserted into a hole formed in the package, wherein the cover portion includes: an aperture member having an aperture facing the opening in the opposing direction of the pair of mirror portions and a positioning portion for positioning the cover portion relative to the housing; and an intermediate member disposed between the main body portion and the aperture member, wherein the hole is a first hole comprising a first hole formed in the aperture member and a second hole formed in the intermediate member, or a second hole comprising a third hole formed in the main body portion and a fourth hole formed in the intermediate member. Spectroscopic module, wherein if the hole is the first hole, the fastening shaft member fixes the aperture member to the intermediate member, and the first or second hole is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member; and if the hole is the second hole, the fastening shaft member fixes the intermediate member to the main body, and the third or fourth hole is an enlarged hole having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member.

3. The positioning portion is in contact with the housing, as described in claim 1 or 2.

4. The spectroscopic module according to any one of claims 1 to 3, wherein the positioning portion is formed to sandwich the housing in a direction perpendicular to the opposing direction of the pair of mirror portions.

5. The spectroscopic module according to any one of claims 1 to 4, wherein, when viewed from opposite directions of the pair of mirror portions, the positioning portion is formed continuously so as to surround the outer edge of the housing.

6. The spectroscopic module according to any one of claims 1 to 5, further comprising a substrate housed in the package, wherein the spectroscopic unit is disposed on the substrate and fixed to the main body via the substrate.

7. A spectroscopic module according to any one of claims 1 to 6, further comprising a light source that emits light, wherein the housing and the light source are arranged adjacent to each other.

8. The spectroscopic module according to any one of claims 1 to 7, wherein a space for housing the housing is formed inside the cover portion, and the inner surface of the cover portion defining the space is formed of a material including at least one of aluminum, silver, and gold.

9. The spectroscopic module according to claim 2, wherein, in the opposing direction of the pair of mirror portions, the surface of the intermediate member opposite to the main body portion is further away from the main body portion than the surface of the housing opposite to the main body portion.

10. A spectroscopic module according to claim 2, comprising a first fastening shaft member and a second fastening shaft member, each of which is the fastening shaft member, wherein the package has a pair of holes formed therein, one of the pair of holes being the first hole, the other of the pair of holes being the second hole, the first fastening shaft member being inserted into the first hole, and the second fastening shaft member being inserted into the second hole.

11. The spectroscopic module according to any one of claims 1 to 10, wherein, in a direction perpendicular to the axial direction of the fastening shaft member, the width of the enlarged hole is greater than the width of the fastening shaft member by a length of 30% or more of the width of the fastening shaft member.

12. A method for manufacturing a spectroscopic module comprising: a spectroscopic unit having a Fabry-Perot interference filter including a pair of mirror portions whose distance from each other is variable; a housing having an opening facing the Fabry-Perot interference filter in the opposing direction of the pair of mirror portions and housing the Fabry-Perot interference filter; a package housing the spectroscopic unit having a main body portion to which the spectroscopic unit is fixed; a cover portion covering the spectroscopic unit; and a fastening shaft member inserted into a hole formed in the package, wherein the cover portion includes an aperture member having an aperture facing the opening in the opposing direction of the pair of mirror portions and a positioning portion for positioning the cover portion relative to the housing; and an intermediate member disposed between the main body portion and the aperture member, wherein the hole is a first hole comprising a first hole formed in the aperture member and a second hole formed in the intermediate member, or a second hole comprising a third hole formed in the main body portion and a fourth hole formed in the intermediate member, the method comprising: preparing the main body portion on which the spectroscopic unit is arranged; A method for manufacturing a spectroscopic module, comprising the steps of: positioning the cover portion on the main body portion such that the intermediate member is positioned between the main body portion and the aperture member; positioning the aperture member with respect to the housing using the positioning portion; if the hole is the first hole, fixing the aperture member to the intermediate member with the fastening shaft member inserted into the first hole; if the hole is the second hole, fixing the intermediate member to the main body portion with the fastening shaft member inserted into the second hole, wherein if the hole is the first hole, the first hole portion or the second hole portion is an enlarged hole portion having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member; and if the hole is the second hole, the third hole portion or the fourth hole portion is an enlarged hole portion having an inner edge larger than the outer edge of the fastening shaft member in a cross section perpendicular to the axial direction of the fastening shaft member.

13. The method for manufacturing a spectroscopic module according to claim 12, wherein, in a direction perpendicular to the axial direction of the fastening shaft member, the width of the enlarged hole is greater than the width of the fastening shaft member by a length of 30% or more of the width of the fastening shaft member.

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