Spectral unit and spectral module

Abstract

The spectroscopic unit of the present invention includes: a housing; a light incident portion provided in the housing; and a Fabry-Perot interference filter disposed in the housing and having a first mirror portion and a second mirror portion with a variable distance therebetween. The light incident portion has: an aperture portion formed with an aperture, and a band-pass filter disposed between the aperture and the Fabry-Perot interference filter. The aperture portion is configured such that the value obtained by dividing the length of the aperture in the direction of the relative direction of the first mirror portion and the second mirror portion by the width of the aperture in the direction perpendicular to the relative direction is 0.5 or more, and such that all of the light passing through the aperture is incident on the band-pass filter.

Description

Technical Field

[0001] The present disclosure relates to a spectroscopic unit and a spectroscopic module. Background Art

[0002] A spectroscopic module is known that includes: a light source that emits light irradiated onto an object, a spectroscopic unit that spectroscopically separates the light reflected by the object or the light transmitted through the object, and a light detector that detects the light spectroscopically separated by the spectroscopic unit (for example, refer to Patent Document 1). With such a spectroscopic module, for example, the components of an object can be analyzed nondestructively.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-145643 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] In the spectroscopic module as described above, a Fabry-Perot interference filter is sometimes applied to the spectroscopic unit. In this case, it is extremely important to improve the spectroscopic accuracy of the Fabry-Perot interference filter, for example, in improving the analysis accuracy of the components of an object.

[0008] An object of the present disclosure is to provide a spectroscopic unit and a spectroscopic module that can improve the spectroscopic accuracy of a Fabry-Perot interference filter.

[0009] Technical Means for Solving the Technical Problem

[0010] A spectroscopic unit according to one aspect of the present disclosure includes: a housing; a light incident portion provided on the housing; and a Fabry-Perot interference filter disposed within the housing and having a first mirror portion and a second mirror portion whose distance from each other is variable. The light incident portion includes: an aperture portion formed with an aperture, and a band-pass filter disposed between the aperture and the Fabry-Perot interference filter. The aperture portion is configured such that the value obtained by dividing the length of the aperture in the direction of the relative direction of the first mirror portion and the second mirror portion by the width of the aperture in the direction perpendicular to the relative direction is 0.5 or more, and such that all of the light passing through the aperture is incident on the band-pass filter.

[0011] In this spectroscopic unit, the aperture part is configured such that the value obtained by dividing the length of the aperture by the width of the aperture is 0.5 or more, and all of the light passing through the aperture is incident on the band-pass filter. Thus, all of the light passing through the aperture is incident on the band-pass filter in a state where the range of its incident angle is reduced. Thereby, the band-pass filter functions properly, and the light in the desired wavelength range is incident on the Fabry-Perot interference filter in a state where the range of its incident angle is reduced. Therefore, the resolution is improved in the spectroscopic spectrum obtained by the Fabry-Perot interference filter. Accordingly, by this spectroscopic unit, the spectroscopic accuracy by the Fabry-Perot interference filter can be improved.

[0012] In the spectroscopic unit according to one aspect of the present disclosure, it may also be that: the aperture part is configured such that all of the light passing through the aperture and transmitting through the band-pass filter is incident on the Fabry-Perot interference filter. Thereby, the generation of stray light in the housing can be suppressed.

[0013] In the spectroscopic unit according to one aspect of the present disclosure, it may also be that: when viewed from the opposite direction, the outer edge of the aperture is located inside the outer edge of the light-transmitting region of the Fabry-Perot interference filter. Thereby, the proportion of the light passing through the aperture and transmitting through the light-transmitting region of the Fabry-Perot interference filter can be increased.

[0014] The spectroscopic unit according to one aspect of the present disclosure may also be that: it further includes a light detector that is disposed in the housing and detects the light transmitting through the Fabry-Perot interference filter. Thereby, the generation of noise caused by stray light can be suppressed, and the spectroscopically analyzed light can be detected with high precision. In addition, since the light detector is disposed in the housing, miniaturization of the spectroscopic unit including the light detector can be achieved.

[0015] In the spectroscopic unit according to one aspect of the present disclosure, it may also be that: the light incident opening and the light exit opening of the aperture are circular. Thereby, an aperture having desired performance can be easily formed.

[0016] In the spectroscopic unit according to one aspect of the present disclosure, it may also be that: the diameter of the aperture is constant between the light incident opening and the light exit opening. Alternatively, it may also be that: the diameter of the aperture changes at a certain rate from the light incident opening toward the light exit opening. Alternatively, it may also be that: the diameter of the aperture changes at a rate of 0 or more from the light incident opening toward the light exit opening, the rate of change is continuous between the light incident opening and the light exit opening, and the rate of change occurs at least in part between the light incident opening and the light exit opening. In these cases, an aperture having desired performance can also be easily formed.

[0017] In the spectroscopic unit according to one aspect of the present disclosure, it may also be that: the region inside the aperture is a space. Thereby, the loss of light due to passing through the aperture can be prevented.

[0018] The spectroscopic unit according to one aspect of the present disclosure may also be: further including: a diaphragm member, which is formed separately from the housing and is provided with a diaphragm portion. Thereby, it is possible to select a suitable material, etc., and improve the degree of freedom in the design of the diaphragm portion. In addition, by forming a large light incident opening in the housing, the positional accuracy of the Fabry-Perot interference filter within the housing can be relaxed, and the positional relationship between the diaphragm and the Fabry-Perot interference filter can be adjusted.

[0019] In the spectroscopic unit according to one aspect of the present disclosure, it may also be: on the diaphragm member, a positioning portion for positioning the housing is provided. Thereby, it is possible to prevent the positional relationship between the diaphragm and the Fabry-Perot interference filter from deviating due to vibration or the like. In addition, since the diaphragm portion and the positioning portion are provided on the diaphragm member, the positional accuracy between the diaphragm portion and the positioning portion can be ensured.

[0020] In the spectroscopic unit according to one aspect of the present disclosure, it may also be: on the diaphragm member, a hole for arranging a light source is formed. Thereby, since the hole and the diaphragm are formed on the diaphragm member, the positional accuracy between the light source and the diaphragm can be ensured.

[0021] In the spectroscopic unit according to one aspect of the present disclosure, it may also be: the diaphragm member constitutes at least a part of the package for accommodating the housing. Thereby, it is possible to more reliably suppress the generation of stray light within the housing.

[0022] In the spectroscopic unit according to one aspect of the present disclosure, it may also be: the band-pass filter is separated from the diaphragm portion through a part of the housing. Thereby, since the band-pass filter is arranged within the housing, the band-pass filter can be protected from physical interference or the like.

[0023] In the spectroscopic unit according to one aspect of the present disclosure, it may also be: the band-pass filter is in contact with the diaphragm portion. Thereby, it is possible to more reliably make all the light passing through the diaphragm incident on the band-pass filter.

[0024] In the spectroscopic unit according to one aspect of the present disclosure, it may also be: the diaphragm portion is formed integrally with the housing. Thereby, it is possible to prevent the positional relationship between the diaphragm and the Fabry-Perot interference filter from deviating due to vibration or the like with a simple structure.

[0025] The spectroscopic module according to one aspect of the present disclosure includes: the above-mentioned spectroscopic unit, a light source, the housing of the spectroscopic unit, and a package for accommodating the light source. The light incident opening of the diaphragm and the light emitting portion of the light source are arranged adjacent to each other along the outer surface of the package.

[0026] According to this spectroscopic module, a reflective spectroscopic module capable of improving the spectroscopic accuracy through the Fabry-Perot interference filter can be realized.

[0027] In the spectroscopic module according to one aspect of the present disclosure, it is also possible that: the light incident opening of the aperture and the light emitting portion of the light source are located within the recess formed on the outer surface. Thus, even in a state where an object is in contact with the outer surface of the aperture member, since the region within the recess is ensured as an optical path, it is possible to irradiate light onto the object and detect the light reflected by the object.

[0028] In the spectroscopic module according to one aspect of the present disclosure, it is also possible that: the aperture is formed on the bottom surface of the first part of the recess. Thus, even in a state where an object is in contact with the outer surface of the aperture member, the light reflected by the object can be reliably incident on the aperture.

[0029] In the spectroscopic module according to one aspect of the present disclosure, it is also possible that: a hole in which the light source is disposed is formed on the bottom surface of the second part of the recess that is deeper than the first part. Thus, even in a state where an object is in contact with the outer surface of the aperture member, the light emitted from the light source can be sufficiently irradiated onto the object.

[0030] In the spectroscopic module according to one aspect of the present disclosure, it is also possible that: a concave curved surface is formed between the bottom surface of the second part and the side surface of the recess. Thus, since the light reflected by the concave curved surface is also irradiated onto the object, the light emitted from the light source can be more sufficiently irradiated onto the object.

[0031] In the spectroscopic module according to one aspect of the present disclosure, it is also possible that: when viewed from the opposite direction, the hole has a size that includes the aperture. Thus, the light emitted from the light source can be irradiated onto the object within a wide range.

[0032] Effects of the Invention

[0033] According to the present disclosure, it is possible to provide a spectroscopic unit and a spectroscopic module that can improve the spectroscopic accuracy through a Fabry - Perot interference filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a cross - sectional view of a light detection device applicable to the spectroscopic module of one embodiment.

[0035] Figure 2 is Figure 2 a perspective view of the Fabry - Perot interference filter shown.

[0036] Figure 3 is along Figure 3 the cross - sectional view taken along line III - III shown.

[0037] Figure 4 is a side view of the spectroscopic module of one embodiment.

[0038] Figure 5 is Figure 4Cross-sectional view of a part of the spectroscopic module shown.

[0039] Figure 6 is Figure 4 Bottom view of a part of the spectroscopic module shown.

[0040] Figure 7 is Figure 5 Cross-sectional view of the spectroscopic unit shown.

[0041] Figure 8 Cross-sectional view of the aperture part of the modified example.

[0042] Figure 9 Cross-sectional view of the light incident part of the modified example.

[0043] Symbol description

[0044] 2... housing, 8... photodetector, 10... Fabry - Perot interference filter, 10a... light transmission region, 14... band - pass filter, 35... first mirror part, 36... second mirror part, 50... spectroscopic module, 51... light source, 51a... light exit part, 53... package, 53a... outer surface, 60... aperture member, 60a... outer surface, 63... recess, 63a... side surface, 63b... curved surface, 64... first part, 64a... bottom surface, 65... second part, 65a... bottom surface, 67... hole, 68... positioning part, 70... aperture part, 71... aperture, 71a... light incident opening, 71b... light exit opening, 80... light incident part, 100... spectroscopic unit. Detailed implementation mode

[0045] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, the same or corresponding parts in each figure are denoted by the same reference numerals, and redundant descriptions are omitted.

[0046] [Optical detection device]

[0047] Before describing the spectroscopic module of one embodiment, an optical detection device applicable to the spectroscopic module will be described. As Figure 1 shown, the optical detection device 1 includes a housing 2. In the present embodiment, the housing 2 is a CAN package having a stem 3 and a cap 4. The cap 4 has a side wall 5 and a top wall 6 formed integrally. The materials of the stem 3 and the cap 4 are, for example, metal. The cap 4 is in a cylindrical shape with the line L as the center line.

[0048] On the inner surface 3a of the base 3, a wiring substrate 7 is fixed. The substrate material of the wiring substrate 7 is, for example, silicon, ceramic, quartz, glass, or plastic, etc. On the wiring substrate 7, a light detector 8 and a temperature detector such as a thermistor (not shown) are mounted. The light detector 8 is arranged in the housing 2 such that the center line of its light-receiving portion coincides with the line L. In the present embodiment, the light detection device 8 is an infrared detector and is composed of a light-receiving element such as an InGaAs photodiode, a thermopile, or a bolometer. In addition, when the light detector 8 detects ultraviolet light, visible light, or near-infrared light, it may be composed of a light-receiving element such as a Si photodiode. Further, the light detector 8 may be composed of one light-receiving element or may be composed of a plurality of light-receiving elements.

[0049] On the wiring substrate 7, a plurality of spacers 9 are fixed. The material of the spacers 9 is, for example, silicon, ceramic, quartz, glass, or plastic, etc. On the plurality of spacers 9, a Fabry - Perot interference filter 10 is fixed. The Fabry - Perot interference filter 10 is arranged in the housing 2 such that the center line of its light-transmitting region 10a coincides with the line L. In addition, the plurality of spacers 9 may be integrally formed with the wiring substrate 7. Further, the Fabry - Perot interference filter 10 may be fixed to one spacer 9.

[0050] On the base 3, a plurality of lead pins 11 are fixed. Each lead pin 11 penetrates the base 3 while maintaining electrical insulation and airtightness with respect to the base 3. Each lead pin 11 is electrically connected to each of the electrode pads of the wiring substrate 7 and the terminals of the Fabry - Perot interference filter 10 via a wire 12. Thereby, input and output of electrical signals to and from each of the Fabry - Perot interference filter 10, the light detector 8, and the temperature detector are made possible.

[0051] An opening 2a is formed in the housing 2. The opening 2a is formed in the top wall 6 of the lid 4 such that its center line coincides with the line L. In the present embodiment, when viewed from a direction parallel to the line L, the opening 2a is circular in shape. On the inner surface 6a of the top wall 6, a light-transmitting member 13 is joined so as to block the opening 2a. The material of the light-transmitting member 13 is, for example, glass. The light-transmitting member 13 has a light-incident surface 13a and a light-emitting surface 13b that face each other in a direction parallel to the line L, and a side surface 13c. The light-incident surface 13a is substantially flush with the outer surface of the top wall 6 of the lid 4 at the opening 2a. The side surface 13c is in contact with the inner surface 5a of the side wall 5 of the lid 4. Such a light-transmitting member 13 is formed by disposing glass particles inside the lid 4 with the opening 2a on the lower side and melting the glass particles.

[0052] On the light-emitting surface 13b of the light-transmitting member 13, a band-pass filter 14 is fixed via an adhesive member 15 made of a light-transmitting material. The band-pass filter 14 selectively transmits light within the measurement wavelength range of the light detection device 1 among the light transmitted through the light-transmitting member 13 (as light within a specified wavelength range and light that should be incident on the light-transmitting region 10a of the Fabry-Perot interference filter 10). In the present embodiment, the band-pass filter 14 is in the shape of a quadrilateral plate. The band-pass filter 14 has a light-incident surface 14a and a light-emitting surface 14b that face each other in a direction parallel to the line L, and four side surfaces 14c. The band-pass filter 14 is constituted, for example, by a light-transmitting member made of silicon or glass, and a dielectric multilayer film formed on the surface of the light-transmitting member. The dielectric multilayer film is constituted by a film made of a high-refractive-index material (such as TiO2 or Ta2O5, etc.) and a film made of a low-refractive-index material (such as SiO2 or MgF2, etc.).

[0053] The adhesive member 15 has a first portion 15a and a second portion 15b. The first portion 15a is the portion of the adhesive member 15 that is disposed between the light-emitting surface 13b of the light-transmitting member 13 and the light-incident surface 14a of the band-pass filter 14. The second portion 15b is the portion of the adhesive member 15 that is disposed between the side surface 14c of the band-pass filter 14 and the inner surface 5a of the side wall 5 of the cover 4 on the light-emitting surface 13b of the light-transmitting member 13.

[0054] In the light detection device 1 configured as described above, when light enters the band-pass filter 14 from the outside of the housing 2 via the opening 2a, the light-transmitting member 13, and the adhesive member 15, only light within a specified wavelength range passes through the band-pass filter 14. The light that has passed through the band-pass filter 14 enters the light-transmitting region 10a of the Fabry-Perot interference filter 10, and light corresponding to the wavelength corresponding to the distance between the first mirror portion 35 and the second mirror portion 36 described later passes through the light-transmitting region 10a. The light that has passed through the light-transmitting region 10a enters the light-receiving portion of the light detector 8 and is detected by the light detector 8. Therefore, by changing the distance between the first mirror portion 35 and the second mirror portion 36 in the Fabry-Perot interference filter 10 and detecting the intensity of the light that has passed through the light-transmitting region 10a in the light detector 8, a spectral spectrum can be obtained.

[0055] [Fabry-Perot interference filter]

[0056] A more detailed description will be given of the above-described Fabry-Perot interference filter 10. As Figure 2 and Figure 3 shown, in the Fabry-Perot interference filter 10, a light-transmitting region 10a that transmits light corresponding to the wavelength corresponding to the distance between the first mirror portion 35 and the second mirror portion 36 is provided. The light-transmitting region 10a is, for example, a cylindrical region centered on the line L.

[0057] The Fabry - Perot interference filter 10 includes a substrate 21. The substrate 21 is, for example, in the shape of a rectangular plate. The material of the substrate 21 is, for example, silicon, quartz, or glass. The substrate 21 has a first surface 21a and a second surface 21b that face each other in a direction parallel to the line L. The first surface 21a is the surface on the light incident side (the side of the band - pass filter 14). The second surface 21b is the surface on the light output side (the side of the photodetector 8).

[0058] A first - layer structure 30 is disposed on the first surface 21a of the substrate 21. The first - layer structure 30 is formed by laminating a first antireflection layer 31, a first stack 32, a first intermediate layer 33, and a second stack 34 in this order on the first surface 21a. A gap (air gap) S is formed by the frame - shaped first intermediate layer 33 between the first stack 32 and the second stack 34. When the material of the substrate 21 is silicon, the materials of the first antireflection layer 31 and the first intermediate layer 33 are, for example, silicon oxide. The thickness of the first intermediate layer 33 is, for example, several tens of nm to several tens of μm.

[0059] The portion of the first stack 32 corresponding to the light - transmitting region 10a functions as a first mirror portion 35. The first stack 32 is formed by alternately laminating a plurality of polysilicon layers and a plurality of silicon nitride layers layer by layer. The optical thickness of each of the polysilicon layers and the silicon nitride layers constituting the first mirror portion 35 is preferably an integer multiple of 1 / 4 of the central transmission wavelength of the light passing through the light - transmitting region 10a. In addition, the first mirror portion 35 may be disposed on the first surface 21a of the substrate 21 without passing through the first antireflection layer 31.

[0060] The portion of the second stack 34 corresponding to the light - transmitting region 10a functions as a second mirror portion 36. The second mirror portion 36 faces the first mirror portion 35 via the gap S in a direction parallel to the line L. The second stack 34 is formed by alternately laminating a plurality of polysilicon layers and a plurality of silicon nitride layers layer by layer. The optical thickness of each of the polysilicon layers and the silicon nitride layers constituting the second mirror portion 36 is preferably an integer multiple of 1 / 4 of the central transmission wavelength of the light passing through the light - transmitting region 10a.

[0061] In addition, in the first stack 32 and the second stack 34, a silicon oxide layer may be disposed instead of the silicon nitride layer. In addition, the materials of the respective layers constituting the first stack 32 and the second stack 34 are not limited to the above - mentioned materials. For example, they may also be titanium oxide, tantalum oxide, zirconium oxide, magnesium fluoride, aluminum oxide, calcium fluoride, silicon, germanium, or zinc sulfide, etc.

[0062] In a portion of the second stacked body 34 corresponding to the gap S, a plurality of through holes 34b are formed. Each through hole 34b extends from the surface 34a of the second stacked body 34 on the side opposite to the first stacked body 32 to the gap S. 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 are used to form the gap S by removing a part of the first intermediate layer 33 by etching.

[0063] In the first stacked body 32, a first electrode 22 is formed so as to surround the light-transmitting region 10a. In the first stacked body 32, a second electrode 23 is formed so as to include the light-transmitting region 10a. The first electrode 22 and the second electrode 23 are formed by doping impurities into the polysilicon layer closest to the gap S in the first stacked body 32 to reduce the impedance. In the second stacked body 34, a third electrode 24 is formed so as to face the first electrode 22 and the second electrode 23 via the gap S. The third electrode 24 is formed by doping impurities into the polysilicon layer closest to the gap S in the second stacked body 34 to reduce the impedance. In addition, the second electrode 23 may have a size equal to or larger than that of the light-transmitting region 10a.

[0064] In the first structural body 30, a pair of first terminals 25 and a pair of second terminals 26 are provided. The pair of first terminals 25 face each other with the light-transmitting region 10a therebetween. Each first terminal 25 is disposed in a through hole extending from the surface 34a of the second stacked body 34 to the first stacked body 32. Each first terminal 25 is electrically connected to the first electrode 22 via a wiring 22a formed in the first stacked body 32. The pair of second terminals 26 face each other with the light-transmitting region 10a therebetween in a direction perpendicular to the direction in which the pair of first terminals 25 face each other. Each second terminal 26 is disposed in a through hole extending from the surface 34a of the second stacked body 34 to the inside of the first intermediate layer 33. Each second terminal 26 is electrically connected to the second electrode 23 via a wiring 23a formed in the first stacked body 32 and is also electrically connected to the third electrode 24 via a wiring 24a formed in the second stacked body 34.

[0065] On the surface 32a of the first stacked body 32 on the side of the second stacked body 34, grooves 27 and 28 are provided. The groove 27 extends in a ring shape so as to surround the connection portion of the wiring 23a with the second terminal 26. The groove 27 electrically insulates the first electrode 22 from the wiring 23a. The groove 28 extends in a ring shape along the inner edge of the first electrode 22. The groove 28 electrically insulates the first electrode 22 from the region inside the first electrode 22 (i.e., the region where the second electrode 23 exists). On the surface 34a of the second stacked body 34, a groove 29 is provided. The groove 29 extends in a ring shape so as to surround the first terminal 25. The groove 29 electrically insulates the first terminal 25 from the third electrode 24. The regions in each of the grooves 27, 28, and 29 may be an insulating material or may be a gap.

[0066] On the second surface 21b of the substrate 21, a second-layer structure 40 is disposed. The second-layer structure 40 is formed by laminating a second antireflection layer 41, a third laminate 42, a second intermediate layer 43, and a fourth laminate 44 in this order on the second surface 21b. The second antireflection layer 41, the third laminate 42, the second intermediate layer 43, and the fourth laminate 44 respectively have the same structure as the first antireflection layer 31, the first laminate 32, the first intermediate layer 33, and the second laminate 34. That is, the second-layer structure 40 has a laminated structure that is symmetric to the first-layer structure 30 with respect to the substrate 21. By forming the second-layer structure 40 in a manner corresponding to the first-layer structure 30, warping of the Fabry - Perot interference filter 10 is suppressed.

[0067] In the third laminate 42, the second intermediate layer 43, and the fourth laminate 44, an opening 40a is formed so as to include the light-transmitting region 10a. The opening 40a is, for example, cylindrical with the line L as the center line and has a diameter substantially the same as that of the light-transmitting region 10a. The opening 40a opens toward the light-emitting side, and the bottom surface of the opening 40a reaches the second antireflection layer 41. The opening 40a allows the light transmitted through the first mirror portion 35 and the second mirror portion 36 to pass through.

[0068] On the light-emitting side surface of the fourth laminate 44, a light-shielding layer 45 is formed. The material of the light-shielding layer 45 is, for example, aluminum or the like. On the surface of the light-shielding layer 45 and the inner surface of the opening 40a, a protective layer 46 is formed. The material of the protective layer 46 is, for example, aluminum oxide. Further, by making the thickness of the protective layer 46 1 to 100 nm (preferably about 30 nm), the optical influence caused by the protective layer 46 can be ignored.

[0069] In the Fabry - Perot interference filter 10 configured as described above, when a voltage is applied between the first terminal 25 and the second terminal 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. As a result, the second mirror portion 36 is adsorbed on the side of the first mirror portion 35 fixed to the substrate 21, and the distance between the first mirror portion 35 and the second mirror portion 36 changes. At this time, since no potential difference is generated between the second electrode and the third electrode 24, the flatness of the second mirror portion 36 in the light-transmitting region 10a is ensured. As described above, in the Fabry - Perot interference filter 10, the distance between the first mirror 35 and the second mirror portion 36 is variable. Here, the wavelength of the light transmitted through the light-transmitting region 10a depends on the distance between the first mirror portion 35 and the second mirror portion 36. Therefore, the wavelength of the light transmitted through the light-transmitting region 10a can be adjusted by adjusting the voltage applied between the first terminal 25 and the second terminal 26.

[0070] [Spectroscopic module]

[0071] A spectroscopic module according to an embodiment to which the above-described optical detection device 1 is applied will be described. In the following description, the relative direction between the first mirror portion 35 and the second mirror portion 36 (in this embodiment, the direction parallel to the line L) is referred to as direction A.

[0072] As Figure 4 shown, the spectroscopic module 50 includes an optical detection device 1, a light source 51, a wiring substrate 52, and a package 53. The light source 51 emits light that irradiates the object 200. The light source 51 is, for example, an infrared lamp that emits light in the near-infrared to mid-infrared wavelength range. On the wiring substrate 52, a plurality of pins 11 of the optical detection device 1 and a plurality of pins of the light source 51 are electrically connected. The package 53 houses the optical detection device 1, the light source 51, the wiring substrate 52, a wireless communication substrate (not shown), a battery case (not shown), and the like. The package 53 is composed of a package body 54 and an aperture member 60. The optical detection device 1 and the light source 51 are supported by the aperture member 60 that forms a part of the package 53. That is, in the spectroscopic module 50, the aperture member 60 functions as a support. In addition, a switch 55 for starting measurement is provided on the package body 54.

[0073] As Figure 5 and Figure 6 shown, the aperture member 60 is mounted on the opening 54b of the package body 54 in a state where its outer surface 60a is flush with the outer surface 54a of the package body 54. More specifically, the aperture member 60 is fixed to the opening 54b by bolts (not shown) or the like in a state where the main body portion 61 of the aperture member 60 is disposed within the opening 54b and the flange portion 62 of the aperture member 60 contacts the opening portion 54b from the inside. In this embodiment, the flange portion 62 is integrally formed on the portion of the inner surface 60b side of the main body portion 61 of the aperture member 60.

[0074] On the outer surface 60a of the aperture member 60, a recess 63 that opens to the outside of the package 53 is formed. The recess 63 is composed of a first portion 64 and a second portion 65. The second portion 65 is deeper than the first portion 64. A concave curved surface 63b is formed between the bottom surface 65a of the second portion 65 and the side surface 63a of the recess 63. The concave curved surface 63b has a shape corresponding to a circular chamfered surface applied to the corner portion formed by the bottom surface 65a and the side surface 63a. On the inner surface 60b of the aperture member 60, a recess 66 that opens to the inside of the package 53 is formed. When viewed from direction A, the outer edge of the recess 66 is located outside the outer edge of the first portion 64 of the recess 63. The recess 66 communicates with the second portion 65 of the recess 63.

[0075] On the bottom surface 64a of the first portion 64 of the recess 63, an aperture 71 is formed. The aperture 71 opens to the bottom surface 64a of the first portion 64 and the bottom surface 66a of the recess 66. On the bottom surface 65a of the second portion 65 of the recess 63, a hole 67 is formed. The hole 67 opens to the bottom surface 65a of the second portion 65 and the inner surface 60b of the aperture member 60. The portion of the hole 67 on the inner surface 60b side of the aperture member 60 is a widened portion 67a whose width is widened in a direction perpendicular to the direction A. When viewed from the direction A, the hole 67 has a size that includes the aperture 71. That is, when the shapes of the hole 67 and the aperture 71 in a cross section perpendicular to the direction A are circular, the minimum diameter of the hole 67 in this cross section is larger than the maximum diameter of the aperture 71 in this cross section.

[0076] In the recess 66, the housing 2 of the light detection device 1 is disposed. More specifically, with the opening 2a of the housing 2 facing the aperture 71, the cover 4 of the housing 2 is disposed in the recess 66. Thereby, the position of the housing 2 in the direction A and the position of the housing 2 in a direction perpendicular to the direction A are positioned. In the present embodiment, the peripheral portion of the recess 66 in the aperture member 60 functions as a positioning portion 68 for positioning the housing 2.

[0077] A light source 51 is disposed in the hole 67. More specifically, with the light emitting portion 51a of the light source 51 disposed in the second portion 65 of the recess 63 and the lead holding portion 51b of the light source 51 disposed in the widened portion 67a of the hole 67, the light source 51 is disposed in the hole 67. Thereby, the position of the light emitting portion 51a in the direction A and the position of the light emitting portion 51a in a direction perpendicular to the direction A are positioned. In the present embodiment, the peripheral portion of the hole 67 in the aperture member 60 functions as a positioning portion 69 for positioning the light emitting portion 51a.

[0078] In the spectroscopic module 50 configured as described above, the light incident opening 71a of the aperture 71 and the light emitting portion 51a of the light source 51 are located in the recess 63 formed in the outer surface 60a of the aperture member 60 that forms a part of the package 53. That is, the light incident opening 71a of the aperture 71 and the light emitting portion 51a of the light source 51 are arranged adjacent to each other along the outer surface 53a of the package 53.

[0079] A more detailed description of the above aperture 71 will be given. In the present embodiment, as Figure 7As shown, in the aperture member 60, the portion between the bottom surface 64a of the first part 64 of the recess 63 and the bottom surface 66a of the recess 66 functions as an aperture portion 70 where the aperture 71 is formed. That is, the aperture portion 70 is provided in the aperture member 60 formed separately from the housing 2 of the light detection device 1, and the band-pass filter 14 is separated from the aperture portion 70 via the top wall 6 of the cover 4 which is a part of the housing 2. In the present embodiment, the light incident portion 80 provided in the housing 2 is constituted by the aperture portion 70 and the band-pass filter 14, and the spectroscopic unit 100 is constituted by the housing 2, the light incident portion 80, the Fabry-Perot interference filter 10, and the photodetector 8.

[0080] The light incident opening 71a of the aperture 71 is the portion of the aperture 71 that opens to the bottom surface 64a of the first part 64 of the recess 63. The light exit opening 71b of the aperture 71 is the portion of the aperture 71 that opens to the bottom surface 66a of the recess 66. The incident angle and the exit angle of the light passing through the aperture 71 (the light passing through the aperture 71 in an ideal state where reflection from the inner surface of the aperture 71, etc. is ignored) are delimited by the light incident opening 71a and the light exit opening 71b. In other words, the light incident opening 71a and the light exit opening 71b are the portions that delimit the incident angle and the exit angle of the light passing through the aperture 71 (the light passing through the aperture 71 in an ideal state where reflection from the inner surface of the aperture 71, etc. is ignored).

[0081] The aperture portion 70 is configured such that the value obtained by dividing the length of the aperture 71 in the direction A by the width of the aperture 71 in the direction perpendicular to the direction A (hereinafter referred to as "the aspect ratio of the aperture 71") is 0.5 or more, and such that all of the light passing through the aperture 71 (the light passing through the aperture 71 in an ideal state where reflection from the inner surface of the aperture 71, etc. is ignored) is incident on the band-pass filter 14. In addition, the aperture portion 70 is configured such that all of the light passing through the aperture 71 and transmitted through the band-pass filter 14 is incident on the Fabry-Perot interference filter 10.

[0082] The length of the aperture 71 in the direction A is the distance between the light incident opening 71a and the light exit opening 71b. The width of the aperture 71 in the direction perpendicular to the direction A is 1 / 2 of the sum of the effective diameters of the light incident opening 71a and the light exit opening 71b. The effective diameter of the light incident opening 71a means the diameter in the case where the shape of the light incident opening 71a is circular, and in the case where the shape of the light incident opening 71a is other than circular, it is the diameter of a circle having the same area. Similarly, the effective diameter of the light exit opening 71b means the diameter in the case where the shape of the light exit opening 71b is circular, and in the case where the shape of the light exit opening 71b is other than circular, it is the diameter of a circle having the same area.

[0083] When viewed from direction A, the outer edge of the aperture 71 is located inside the outer edge of the light-transmitting region 10a of the Fabry-Perot interference filter 10. The region inside the aperture 71 is a space. The aperture 71 is a portion that extends in direction A from the light-emitting opening 71b that defines the light-emitting angle and has a constant width. In the present embodiment, the light-incident opening 71a and the light-emitting opening 71b of the aperture 71 are circular, and the diameter of the aperture 71 is constant between the light-incident opening 71a and the light-emitting opening 71b. That is, the region inside the aperture 71 is cylindrical.

[0084] [Function and effect]

[0085] As described above, in the spectroscopic unit 100, the aperture unit 70 is configured such that the aspect ratio of the aperture 71 is 0.5 or more and all of the light passing through the aperture 71 is incident on the band-pass filter 14. Therefore, all of the light passing through the aperture 71 is incident on the band-pass filter 14 in a state where the range of its incident angle is reduced. Thereby, the band-pass filter 14 functions properly, and light in a desired wavelength range is incident on the Fabry-Perot interference filter 10 in a state where the range of its incident angle is reduced. Therefore, the resolution is improved in the spectroscopic spectrum obtained by the Fabry-Perot interference filter 10. Thereby, the spectroscopic accuracy of the light passing through the Fabry-Perot interference filter 10 can be improved by the spectroscopic unit 100. In addition, in order to improve the resolution in the spectroscopic spectrum, the aspect ratio of the aperture 71 is preferably 1 or more, and more preferably 2 or more.

[0086] In addition, in the spectroscopic unit 100, the aperture unit 70 is configured such that all of the light passing through the aperture 71 and transmitting through the band-pass filter 14 is incident on the Fabry-Perot interference filter 10. Thereby, generation of stray light can be suppressed inside the housing 2.

[0087] In addition, in the spectroscopic unit 100, when viewed from direction A, the outer edge of the aperture 71 is located inside the outer edge of the light-transmitting region 10a of the Fabry-Perot interference filter 10. Thereby, the proportion of the light passing through the aperture 71 and transmitting through the light-transmitting region 10a of the Fabry-Perot interference filter 10 can be increased.

[0088] In addition, in the spectroscopic unit 100, the photodetector 8 that detects the light transmitting through the Fabry-Perot interference filter 10 is disposed inside the housing 2. Thereby, generation of noise due to stray light can be suppressed, and the spectroscopically analyzed light can be detected with high precision. In addition, since the photodetector 8 is disposed inside the housing 2, miniaturization of the spectroscopic unit 100 including the photodetector 8 can be achieved.

[0089] In addition, in the beam splitting unit 100, the light incident opening 71a and the light exit opening 71b of the aperture 71 are circular in shape. Thus, it is possible to easily form the aperture 71 having desired performance.

[0090] In addition, in the beam splitting unit 100, the diameter of the aperture 71 is constant between the light incident opening 71a and the light exit opening 71b. Thus, it is possible to easily form the aperture 71 having desired performance.

[0091] In addition, in the beam splitting unit 100, the area inside the aperture 71 is a space. Thus, it is possible to prevent light loss caused by passing through the aperture 71.

[0092] In addition, in the beam splitting unit 100, the aperture member 60 provided with the aperture portion 70 is formed separately from the frame body 2. Thus, it is possible to increase the degree of freedom in the design of the aperture portion 70, such as the selection of a suitable material. In addition, by forming a large opening 2a in the frame body 2, the positional accuracy of the Fabry - Perot interference filter 10 inside the frame body 2 can be relaxed, and the positional relationship between the aperture 71 and the Fabry - Perot interference filter 10 can be adjusted.

[0093] In addition, in the beam splitting unit 100, the positioning portion 68 for positioning the frame body 2 is provided on the aperture member 60. Thus, it is possible to prevent the positional relationship between the aperture 71 and the Fabry - Perot interference filter 10 from deviating due to vibration or the like. In addition, since the aperture portion 70 and the positioning portion 68 are provided on the aperture member 60, it is possible to ensure the positional accuracy between the aperture portion 70 and the positioning portion 68.

[0094] In addition, in the beam splitting unit 100, the hole 67 for arranging the light source 51 is formed in the aperture member 60. Thus, since the hole 67 and the aperture 71 are formed in the aperture member 60, it is possible to ensure the positional accuracy between the light source 51 and the aperture 71.

[0095] In addition, in the beam splitting unit 100, the aperture member 60 forms a part of the package 53 that houses the frame body 2. Thus, it is possible to more reliably suppress stray light generated inside the frame body 2.

[0096] In addition, in the beam splitting unit 100, the band - pass filter 14 is separated from the aperture portion 70 via a part of the frame body 2. Thus, since the band - pass filter 14 is arranged inside the frame body 2, it is possible to protect the band - pass filter 14 from physical interference and the like.

[0097] In addition, in the beam splitting module 50, the light incident opening 71a of the aperture 71 and the light exit portion 51a of the light source 51 are arranged adjacent to each other along the outer surface 53a of the package 53. Therefore, with the beam splitting module 50, it is possible to realize a reflective beam splitting module 50 with improved beam splitting accuracy through the Fabry - Perot interference filter 10.

[0098] In addition, in the spectroscopic module 50, the light incident opening 71a of the aperture 71 and the light emitting portion 51a of the light source 51 are located within the recess 63 formed in the outer surface 60a of the aperture member 60. Thus, as Figure 5 shown, even in a state where the outer surface 60a of the aperture member 60 is in contact with the object 200, the area within the recess 63 is ensured as an optical path, so that irradiation of light to the object 200 and detection of light reflected by the object 200 can be performed.

[0099] In addition, in the spectroscopic module 50, the aperture 71 is formed on the bottom surface 64a of the first portion 64 of the recess 63. Thus, even in a state where the outer surface 60a of the aperture member 60 is in contact with the object 200, the light reflected by the object 200 can be reliably incident on the aperture 71.

[0100] In addition, in the spectroscopic module 50, a hole 67 in which the light source 51 is disposed is formed on the bottom surface 65a of the second portion 65 of the recess 63 that is deeper than the first portion 64. Thus, even in a state where the outer surface 60a of the aperture member 60 is in contact with the object 200, the light emitted from the light source 51 can be sufficiently irradiated to the object 200.

[0101] In addition, in the spectroscopic module 50, a concave curved surface 63b is formed between the bottom surface 65a of the second portion 65 and the side surface 63a of the recess 63. Thus, since the light reflected by the concave curved surface 63b is also irradiated to the object 200, the light emitted from the light source 51 can be more sufficiently irradiated to the object 200.

[0102] In addition, in the spectroscopic module 50, when viewed from direction A, the hole 67 has a size that includes the aperture 71. Thus, the light emitted from the light source 51 can be irradiated to the object 200 over a wide range.

[0103] [Modification Example]

[0104] The present disclosure is not limited to the above-described embodiments. For example, the above-described reflective spectroscopic module 50 can perform irradiation of light to the object 200 and detection of light reflected by the object 200 even in a state where the outer surface 60a of the aperture member 60 is separated from the object 200 without being in contact with the object 200. In addition, the spectroscopic unit 100 can also be applied to a transmissive spectroscopic module 50 that detects light emitted from the light source 51 and transmitted through the object 200. In addition, the spectroscopic unit 100 may not include the photodetector 8, and the light transmitted through the Fabry - Perot interference filter 10 may be detected by a photodetector 8 disposed outside the housing 2.

[0105] In addition, the aperture portion 70 may be configured such that the major axis ratio of the aperture 71 is 0.5 or more, and all of the light passing through the aperture 71 is incident on the band-pass filter 14 at least. Further, when viewed from direction A, the outer edge of the aperture 71 may be located outside the outer edge of the light-transmitting region 10a of the Fabry-Perot interference filter 10. In this case, the amount of light entering the housing 2 can be sufficiently ensured.

[0106] In addition, as Figure 8 (a) shown in, the diameter of the aperture 71 may also be reduced from the light incident opening 71a toward the light exit opening 71b at a certain reduction rate (a certain reduction rate greater than 0). That is, the region within the aperture 71 may also be in the shape of a frustum of a cone with a decreasing diameter from the light incident opening 71a toward the light exit opening 71b. In addition, as Figure 8 (b) shown in, the diameter of the aperture 71 may also be reduced from the light incident opening 71a toward the light exit opening 71b at a reduction rate of 0 or more. That is, a part of the region within the aperture 71 may be cylindrical. In this case, the reduction rate may also be continuous (i.e., without a step difference) between the light incident opening 71a and the light exit opening 71b and increase in at least a part between the light incident opening 71a and the light exit opening 71b. In the aperture 71 shown in Figure 8 (b), the reduction rate increases in the part including the light exit opening 71b.

[0107] In addition, the diameter of the aperture 71 may also be increased from the light incident opening 71a toward the light exit opening 71b at a certain expansion rate (a certain expansion rate greater than 0). That is, the region within the aperture 71 may also be in the shape of a frustum of a cone with an increasing diameter from the light incident opening 71a toward the light exit opening 71b. In addition, the diameter of the aperture 71 may also be reduced from the light incident opening 71a toward the light exit opening 71b at an expansion rate of 0 or more. That is, a part of the region within the aperture 71 may be cylindrical. In this case, the expansion rate may also be continuous (i.e., without a step difference) between the light incident opening 71a and the light exit opening 71b and decrease in at least a part (for example, the part including the light incident opening 71a) between the light incident opening 71a and the light exit opening 71b.

[0108] That is, the diameter of the aperture 71 may also change at a certain rate of change from the light incident opening 71a toward the light exit opening 71b. Or, the diameter of the aperture 71 changes at a rate of change of 0 or more from the light incident opening 71a toward the light exit opening 71b, and the rate of change may also be continuous between the light incident opening 71a and the light exit opening 71b and change in at least a part between the light incident opening 71a and the light exit opening 71b. In either case, the aperture 71 having desired performance can be easily formed.

[0109] In addition, asFigure 9 As shown in (a) of, the band-pass filter 14 may also be in contact with the aperture unit 70. In Figure 9 In the light incident unit 80 shown in (a) of, the band-pass filter 14 is disposed on the top wall 6 of the cover 4 so as to cover the opening 2a of the housing 2, and the aperture unit 70 is disposed on the band-pass filter 14. When the band-pass filter 14 is in contact with the aperture unit 70, all of the light passing through the aperture 71 is more reliably incident on the band-pass filter 14. In addition, in Figure 9 In the light incident portion 80 shown in (a) of, the aperture unit 70 is also an aperture member 60 formed separately from the housing 2. In addition, as Figure 9 shown in (b) of, the aperture unit 70 may also be integrally formed with the housing 2. In Figure 9 In the light incident unit 80 shown in (b) of, the top wall 6 of the cover 4 functions as the aperture unit 70, and the opening 2a formed in the top wall 6 functions as the aperture 71. When the aperture unit 70 is integrally formed with the housing 2, it is possible to prevent a deviation in the positional relationship between the aperture 71 and the Fabry-Perot interference filter 10 due to vibration or the like with a simple structure. In addition, in Figure 9 In the light incident portion 80 shown in (b) of, the light transmissive member 13 is fixed to the inner surface 6a of the top wall 6 by the adhesive member 15, and the band-pass filter 14 is fixed to the light exit surface 13b of the light transmissive member 13, but the band-pass filter 14 may also be fixed to the inner surface 6a of the top wall 6 by the adhesive member 15. In addition, in the light incident unit 80, a space may be provided between the aperture 71 and the band-pass filter 14. In addition, within the aperture 71, for example, a lens and / or an optical fiber may be disposed.

Claims

1. A light splitting unit, characterized in that, Comprising: A housing having a top wall provided with an opening for light incidence and side walls extending in a direction intersecting the top wall; A light incident portion provided in the housing; A Fabry - Perot interference filter disposed within the housing, having a first mirror portion and a second mirror portion with a variable distance therebetween; And An aperture member formed separately from the housing and provided with an aperture portion, The light incident portion having: the aperture portion formed with an aperture, and a band - pass filter disposed between the aperture and the Fabry - Perot interference filter, The aperture portion is configured to be separate from the housing and separated from the band - pass filter, and the aperture is arranged to face the opening, and the width of the aperture is smaller than the width of the opening of the housing, The width of the aperture portion is greater than the width of the opening of the housing, and the aperture portion is arranged to face the outer surface of the top wall, In the aperture member, a positioning portion for positioning the housing is provided, In a state where the opening of the housing faces the aperture, the positioning portion faces the outer surface of the side wall, so that the position of the housing in a direction perpendicular to the relative direction of the first mirror portion and the second mirror portion is positioned.

2. The light splitting unit according to claim 1, characterized in that, The aperture is configured such that all of the light passing through the aperture and the band - pass filter is incident on the Fabry - Perot interference filter.

3. The light splitting unit according to claim 1, characterized in that, When viewed from the relative direction, the outer edge of the aperture is located inside the outer edge of the light - transmitting region of the Fabry - Perot interference filter.

4. The light splitting unit according to claim 2, characterized in that, When viewed from the relative direction, the outer edge of the aperture is located inside the outer edge of the light - transmitting region of the Fabry - Perot interference filter.

5. The light splitting unit according to claim 1, characterized in that, Further comprising: a light detector disposed within the housing for detecting light transmitted through the Fabry - Perot interference filter.

6. The light splitting unit according to claim 2, characterized in that, Further comprising: a light detector disposed within the housing for detecting light transmitted through the Fabry - Perot interference filter.

7. The light splitting unit according to claim 3, characterized in that, Further comprising: a light detector disposed within the housing for detecting light transmitted through the Fabry - Perot interference filter.

8. The light splitting unit according to claim 4, characterized in that, Further comprising: a light detector disposed within the housing for detecting light transmitted through the Fabry - Perot interference filter.

9. The light splitting unit according to any one of claims 1 to 8, characterized in that, The light incident opening and the light exit opening of the aperture are circular.

10. The light splitting unit according to claim 9, characterized in that, The diameter of the aperture is constant between the light incident opening and the light exit opening.

11. The light splitting unit according to claim 9, characterized in that, The diameter of the aperture changes at a certain rate from the light incident opening towards the light exit opening.

12. The light splitting unit according to claim 9, characterized in that, The diameter of the aperture changes at a rate of 0 or more from the light incident opening towards the light exit opening, The rate of change is continuous between the light incident opening and the light exit opening and changes at least in part between the light incident opening and the light exit opening.

13. The spectroscopic unit according to any one of claims 1 to 8, characterized in that, The region within the aperture is a space.

14. The spectroscopic unit according to claim 9, characterized in that, The region within the aperture is a space.

15. The spectroscopic unit according to claim 10, characterized in that, The region within the aperture is a space.

16. The spectroscopic unit according to claim 11, characterized in that, The region within the aperture is a space.

17. The spectroscopic unit according to claim 12, characterized in that, The region within the aperture is a space.

18. The spectroscopic unit according to claim 1, characterized in that, In the aperture member, a hole for arranging a light source is formed.

19. The spectroscopic unit according to claim 1, characterized in that, The aperture member forms at least a part of a package for accommodating the housing.

20. The spectroscopic unit according to claim 18, characterized in that, The aperture member forms at least a part of a package for accommodating the housing.

21. The spectroscopic unit according to any one of claims 1, 18 to 20, characterized in that, The band-pass filter is separated from the aperture through a part of the housing.

22. A spectroscopic module, characterized in that, Comprising: The spectroscopic unit according to any one of claims 1 to 21; A light source; and A package that houses the housing of the spectroscopic unit and the light source, The light incident opening of the aperture and the light emitting portion of the light source are arranged adjacent to each other along the outer surface of the package.

23. The spectroscopic module according to claim 22, characterized in that, The light incident opening of the aperture and the light emitting portion of the light source are located in a recess formed in the outer surface.

24. The spectroscopic module according to claim 23, characterized in that, The aperture is formed on the bottom surface of the first part of the recess.

25. The spectroscopic module according to claim 24, characterized in that, A hole in which the light source is arranged is formed on the bottom surface of the second part of the recess that is deeper than the first part.

26. The spectroscopic module according to claim 25, characterized in that, A concave curved surface is formed between the bottom surface of the second part and the side surface of the recess.

27. The spectroscopic module according to claim 25 or 26, characterized in that, When viewed from the opposite direction, the hole has a size that includes the aperture.

Images