WO2012114632A1

WO2012114632A1 - Spectrometer module

Info

Publication number: WO2012114632A1
Application number: PCT/JP2011/079541
Authority: WO
Inventors: 隆文能野; 柴山　勝己
Original assignee: 浜松ホトニクス株式会社
Priority date: 2011-02-23
Filing date: 2011-12-20
Publication date: 2012-08-30
Also published as: JP5718091B2; JP2012173208A

Abstract

A spectrometer module (1) is provided with a package body (2), a package lid (7) and a support substrate (11), a transmission grating element (13), a mirror element (20), and a photodetection element (15). A cavity (3) is formed in the body (2). The lid (7) and the substrate (11) are attached to the body (2) in such a manner as to face the bottom surface (3b) of the cavity (3), and allow light (L) to penetrate inside the cavity (3) from outside the cavity (3). The grating element (13) is supported by the substrate (11), and diffracts light (L) emitted from outside the cavity (3), and allows the light (L) to penetrate to the bottom surface (3b) side of the cavity (3). The mirror element (20) is positioned on the bottom surface (3b) of the cavity (3), and reflects the light (L) diffracted by the grating element (13). The photodetection element (15) is supported by the substrate (11), and detects the light (L) reflected by the mirror element (20).

Description

Spectroscopic module

The present invention relates to a spectroscopic module.

As a conventional downsized spectroscopic module, a package provided with a light incident portion, a reflective grating provided on a curved surface which is a predetermined inner surface of the package, and attached to the package so as to face the reflective grating A device including a light detection element is known (see, for example, Patent Documents 1 to 3). In such a spectroscopic module, the light that has entered the package via the light incident portion is split and reflected by the reflective grating, and the light is detected by the light detection element.

JP 2004-309146 A JP 2000-298066 A JP 2009-535621 A

In the small spectroscopic module as described above, the spectroscopic characteristics of the reflective grating greatly depend on the formation accuracy of the curved surface of the package. Therefore, if the curved surface of the package is not accurately formed with a predetermined curvature, the spectral characteristics change, and as a result, the reliability may be reduced.

Therefore, an object of the present invention is to provide a spectroscopic module capable of preventing a decrease in reliability due to a change in spectroscopic characteristics while achieving miniaturization.

A spectroscopic module according to an aspect of the present invention includes a housing member in which a cavity is formed, a light passage member that is attached to the housing member so as to face an inner surface of the cavity, and allows light to pass from the outside of the cavity into the cavity. A spectroscopic unit that is supported by the member and splits light incident from outside the cavity and transmits the light to the inner surface side of the cavity; a reflecting unit that is disposed on the inner surface of the cavity and reflects the light dispersed by the spectroscopic unit; and a light passage member And a light detecting element that detects light reflected by the reflecting portion.

In this spectroscopic module, the transmissive spectroscopic unit and the light detection element are supported by a light passing member that allows light to pass from the outside of the cavity into the cavity. Therefore, it is possible to suppress the change in the spectral characteristics of the spectroscopic unit due to the state of the housing member. Furthermore, even if the spectroscopic unit, the reflection unit, and the light detection element are arranged close to each other, the light reflected from the light incident surface of the spectroscopic unit is stray light compared to the case where the transmission type spectroscopic unit is supported by the housing member. It can suppress detecting with a photon detection element. Therefore, according to this spectroscopic module, it is possible to prevent a reduction in reliability due to a change in spectroscopic characteristics while achieving miniaturization.

Note that “the spectroscopic unit and the light detection element are supported by the light passage member” not only means that the spectroscopic unit and the light detection element are directly supported by the light passage member, but also the spectroscopic unit and the light detection unit. This also includes the case where the element is supported indirectly by the light passage member (that is, via some member other than the housing member).

Here, the light passing member or the light detection element may be provided with a light incident part so as to be positioned in front of the spectroscopic part. According to this, light can be selectively and reliably incident on a predetermined position of the spectroscopic unit. The former stage means the upstream side in the light traveling direction.

At this time, the light passing member may be provided with a light emitting part so as to be located in the subsequent stage of the spectroscopic part and in the preceding stage of the reflecting part. According to this, only the light to be detected among the light separated by the spectroscopic unit can be passed. The latter stage means the downstream side in the light traveling direction.

Furthermore, at least one of the light incident part and the light emitting part may be configured to move relative to the spectroscopic part. According to this, the wavelength range of the light to be detected can be changed.

Further, the cavity may be hermetically sealed against the outside air. According to this, it is possible to prevent at least a member such as the reflection portion facing the cavity from deteriorating due to moisture or the like.

The reflecting portion is a mirror element disposed on the inner surface of the cavity, and the mirror element includes a base material having a concave portion formed on the surface and a molding layer disposed on the base material. The first portion located in the concave portion when viewed from the depth direction of the concave portion, and the second portion located on the surface of the base material in a state of being connected to the first portion, An optical function unit that is a mirror may be provided on a predetermined surface that faces the inner surface of the concave portion. According to this, even if the stress generated by the temperature change at the time of use or the like is concentrated on the concave portion of the base material, the first portion located in the concave portion of the base material by the second portion located on the surface of the base material The part of is pressed. Thereby, it can prevent that a molding layer peels from a base material. Furthermore, the shrinkage and expansion of the molding layer due to temperature changes during use are absorbed by the second part located on the surface of the base material, and the shrinkage of the first part located in the recess of the base material And swelling is relieved. Thereby, the deformation | transformation of the predetermined surface of a 1st part can be prevented, and also the deformation | transformation of the optical function part provided in the predetermined surface can be prevented.

According to the present invention, it is possible to prevent a decrease in reliability due to a change in spectral characteristics while achieving miniaturization.

It is a longitudinal cross-sectional view of the spectroscopy module of the 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the modification of the spectroscopy module of FIG. It is a longitudinal cross-sectional view of the spectroscopy module of the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the modification of the spectroscopy module of FIG. It is a longitudinal cross-sectional view of the spectroscopy module of the 3rd Embodiment of this invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same or equivalent part, and the overlapping description is abbreviate | omitted.
[First Embodiment]

As shown in FIG. 1, the spectroscopic module 1 includes a package body (accommodating member) 2 having a rectangular parallelepiped box shape (for example, 35 mm in width, 30 mm in depth, and 15 mm in height) made of light-absorbing resin or ceramic. Yes. The package body 2 is formed with a cavity 3 that is a concave section having a rectangular cross section that opens on one side, and wide sections 4 to 6 having a rectangular section that widen the opening 3a of the cavity 3 in stages.

A rectangular plate-shaped package lid (light passage member) 7 made of light-absorbing resin or ceramic is airtightly fixed to the widened portion 6 outside the package body 2 by adhesion or the like. A light incident hole 8 is formed in the package lid 7, and a window member 9 is airtightly fixed to the light incident hole 8. The cavity 3 is hermetically sealed against the outside air by the package body 2, the package lid 7, and the window member 9.

A rectangular plate-like support substrate (light passage member) 11 made of light-absorbing resin or ceramic is fixed to the widened portion 4 inside the package body 2 by adhesion or the like. A light incident slit (light incident portion) 12 is formed in the support substrate 11 so as to face the light incident hole 8. The opening on the bottom surface 3b side of the light incident slit 12 is widened so as to expand toward the bottom surface 3b.

The package lid 7 and the support substrate 11 are attached to the package body 2 so as to face the bottom surface 3b which is a predetermined inner surface of the cavity 3. The package lid 7 and the support substrate 11 allow light L to pass from outside the cavity 3 into the cavity 3 through the light incident hole 8, the window member 9, and the light incident slit 12.

A rectangular plate-shaped transmission grating element (spectral part) 13 made of quartz is disposed on the cavity 3 side with respect to the support substrate 11 so as to face the light incident slit 12. The transmissive grating element 13 is attached to the support substrate 11 via a cylindrical light absorbing member 14. That is, the transmissive grating element 13 is indirectly supported by the support substrate 11. The transmissive grating element 13 splits the light L incident from the outside of the cavity 3 through the light incident hole 8, the window member 9 and the light incident slit 12 and transmits the light L to the bottom surface 3 b side of the cavity 3. The light absorbing member 14 surrounds the optical path of the light L from the opening on the bottom surface 3 b side of the light incident slit 12 to the light incident surface 13 a of the transmissive grating element 13.

A mirror element (reflecting part) 20 is disposed on the bottom surface 3 b of the cavity 3. The mirror element 20 reflects the light L dispersed by the transmissive grating element 13 toward the support substrate 11 in the optical function unit 21 that is a mirror. The mirror element 20 includes a base plate 22 made of silicon, plastic, ceramic, glass, or the like (for example, an outer shape of 20 mm × 20 mm and a thickness of 2 mm). On the surface 22a of the base material 22, a concave portion 23 having a regular quadrangular pyramid shape that is widened toward the opening 23a is formed.

On the base material 22, a molding layer 24 formed by photocuring a replicating optical resin such as a photocurable epoxy resin, acrylic resin, fluorine-based resin, silicone or organic-inorganic hybrid resin is disposed. . The outer edge 24a of the molding layer 24 surrounds the center of the bottom surface 23b of the recess 23 when viewed from the depth direction (that is, one side) of the recess 23, and at least a part of the outer edge 24a has a square shape. It passes through the outside of each side of the opening 23a. The material of the molding layer 24 is not limited to the above-described photo-curing resin material, but can be variously molded and cured by a molding die, such as a thermosetting resin material, low-melting glass, or organic / inorganic hybrid glass. A suitable material (molding material) can be applied.

The molding layer 24 has a body portion (first portion) 25 and a ride-up portion (second portion) 26 that are integrally formed. The main body 25 is located in the recess 23 when viewed from the depth direction of the recess 23. The ride-up part 26 is located on the surface 22 a of the base material 22 in a state of being connected to the main body part 25. The ride-up portion 26 is provided outside each side of the square-shaped opening 23a, faces the recess 23 and sandwiches the recess 23.

The molding layer 24 has a concave curved surface (predetermined surface) 24b facing the bottom surface 23b, which is a predetermined inner surface of the recess 23. The curved surface 24 b is a curved surface that is recessed toward the center of the bottom surface 23 b of the recess 23, and extends from the main body portion 25 to each riding-up portion 26 through the midpoint of each side of the square opening 23 a. On the curved surface 24 b of the molding layer 24, a reflective film 27 that is a deposited film of Al, Au, or the like is formed. The reflective film 27 is formed in a predetermined region on the main body 25 on the curved surface 24b, and the surface of the reflective film 27 is the optical function unit 21 that is a mirror.

On the opposite side of the cavity 3 with respect to the support substrate 11, a light detecting element 15 having a substrate 15b made of a semiconductor or the like and a light detecting portion 15a formed on the substrate 15b is arranged. A light passage hole 16 is formed in the support substrate 11 so as to face the light detection unit 15a. The opening on the bottom surface 3b side of the light passage hole 16 is widened so as to expand toward the bottom surface 3b. The light detection unit 15a is configured by, for example, one-dimensionally arranging photodiodes. The light detection element 15 detects the light L reflected by the mirror element 20 and passed through the light passage hole 16. The light detection element 15 is not limited to the photodiode array, and may be a C-MOS image sensor, a CCD image sensor, or the like.

The surface 11a of the support substrate 11 is provided with a wiring 17 made of a single layer film such as Al or Au, or a laminated film such as Cr—Pt—Au, Ti—Pt—Au, Ti—Ni—Au, Cr—Au. It has been. Each of the plurality of external terminals of the light detection element 15 is connected to each of the plurality of wirings 17 by face-down bonding via the bumps 18. That is, the light detection element 15 is indirectly supported by the support substrate 11. A plurality of leads 19 are embedded in the package body 2 such that the base end portion is exposed to the intermediate widened portion 5 and the tip end portion extends to the outside. Each wiring 17 is connected to the base end portion of each lead 19 by a wire 31. A light absorption layer 42 is formed on the surface 11 a of the support substrate 11. The light absorption layer 42 covers the wiring 17 except for the portion where the bumps 18 and the leads 19 are disposed.

In the spectroscopic module 1 configured as described above, the light L incident from the outside of the cavity 3 through the light incident hole 8, the window member 9, and the light incident slit 12 is split by the transmissive grating element 13 and the cavity 3. Is transmitted to the bottom surface 3b side. The light L dispersed by the transmissive grating element 13 is reflected by the mirror element 20 to the support substrate 11 side. The light L reflected by the mirror element 20 enters the light detection unit 15 a through the light passage hole 16. As a result, the electrical signal output from the light detection element 15 is taken out of the spectroscopic module 1 via the bump 18, the wiring 17, the wire 31 and the lead 19.

As described above, in the spectroscopic module 1, the transmission grating element 13 and the light detection element 15 are formed by the package lid 7 that allows the light L to pass from the outside of the cavity 3 into the cavity 3 and the support substrate 11 of the support substrate 11. It is supported. Therefore, it is possible to suppress the spectral characteristics of the transmission type grating element 13 from being changed due to the state of the package body 2 (formation accuracy, shrinkage and expansion due to temperature change during use, etc.). Furthermore, even if the transmissive grating element 13, the mirror element 20, and the light detecting element 15 are arranged close to each other, the light of the transmissive grating element 13 can be compared with the case where the transmissive grating element 13 is supported by the package body 2. It can suppress that the light reflected by the entrance plane 13a is detected by the light detection element 15 as stray light. Therefore, according to the spectroscopic module 1, it is possible to prevent a decrease in reliability due to a change in spectral characteristics while achieving miniaturization.

Here, in the spectroscopic module 1, the structure for suppressing the light reflected by the light incident surface 13a of the transmissive grating element 13 from becoming stray light is simplified as follows. That is, the light absorption member 14 for attaching the transmissive grating element 13 to the support substrate 11 surrounds the optical path of the light L from the light incident slit 12 to the light incident surface 13a. On the other hand, when the transmissive grating element 13 is supported by the package body 2, in addition to the structure for supporting the transmissive grating element 13, the light reflected by the light incident surface 13a of the transmissive grating element 13 is prevented from becoming stray light. Therefore, the structure may be complicated, for example, a structure is required. Even if the light absorbing member 14 does not surround the optical path of the light L from the light incident slit 12 to the light incident surface 13a, the transmissive grating element 13 is more transmissive than the case where it is supported by the package body 2. It is possible to suppress the light reflected by the light incident surface 13a of the grating element 13 from becoming stray light.

In the spectroscopic module 1, since the transmissive grating element 13 is supported by the support substrate 11, the optical path of the light L from the mirror element 20 to the light detection element 15 can be simplified. On the other hand, when the transmission type grating element 13 is supported on the package body 2, the light L to be detected is reflected a plurality of times so that the light L to be detected is not kicked by the structure for the support. There is a possibility that the optical path of the light L from the element 20 to the light detection element 15 may be complicated. Furthermore, light other than the light L to be detected hits the supporting structure, and stray light due to multiple reflection may occur.

In the spectroscopic module 1, since the transmissive grating element 13 is supported by the support substrate 11, the transmissive grating element 13 can be easily and reliably fixed in a predetermined posture. For example, in order to adjust the optical path of the light L or to suppress the light reflected by the light incident surface 13a of the transmissive grating element 13 from becoming stray light, the transmissive grating element 13 may be disposed at an angle. Is possible.

In addition, when a reflective grating is provided on a curved surface, which is a predetermined inner surface of a package, as in a conventional spectroscopic module, it is necessary to change the curvature of the curved surface of the package according to the wavelength range of light to be detected. , The sharing of the package is hindered. On the other hand, if the package is to be shared, the wavelength range of light to be detected is limited. On the other hand, in the spectroscopic module 1, if the transmission grating element 13 is changed, the wavelength range of light to be detected can be changed, so that the package body 2 can be shared. In addition, in the spectroscopic module 1, it is not necessary to employ a reflective grating having a spherical optical surface when miniaturized due to the adoption of the flat plate-like transmissive grating element 13, and thus the degree of freedom in optical design of the grating. Spread. Therefore, according to the spectroscopic module 1, it is possible to realize both a reduction in size and variations in various product characteristics (wavelength band and resolution).

In addition, when a reflective grating is provided on a curved surface, which is a predetermined inner surface of a package, as in a conventional spectral module, the curved surface of the package is formed with a predetermined curvature with high accuracy in order to prevent changes in spectral characteristics. It is necessary to reduce the cost of the spectroscopic module. On the other hand, in the spectroscopic module 1, since it is not necessary to form such a highly accurate curved surface and to form a grating on the curved surface, the cost of the spectroscopic module 1 can be reduced.

Further, in the spectroscopic module 1, the transmission grating element 13 and the light detection element 15 are attached to the support substrate 11, and the mirror element 20 is attached to the package body 2, and then the support substrate 11, the package body 2, In combination, the transmission grating element 13, the mirror element 20, and the light detection element 15 can be positioned relative to each other. Moreover, since there is no structure for supporting the transmission type grating element 13 on the package body 2, the mirror element 20 can be easily attached to the package body 2.

Further, the support substrate 11 is provided with a light incident slit 12 so as to be positioned in front of the transmissive grating element 13 (that is, upstream in the traveling direction of the light L). As a result, the light L can be selectively and reliably incident on a predetermined position of the transmissive grating element 13.

Further, the cavity 3 formed in the package body 2 is hermetically sealed against the outside air by the package body 2, the package lid 7, and the window member 9. Thereby, it is possible to prevent the members facing the cavity 3 such as the transmission type grating element 13, the mirror element 20, and the light detection element 15 from being deteriorated by moisture or the like.

Further, the mirror element 20 is employed as a reflecting portion that reflects the split light L. In the mirror element 20, even if stress generated due to a temperature change or the like during use is concentrated on the concave portion 23 of the base material 22, the raised portion 26 positioned on the surface 22 a of the base material 22 causes the concave portion 23 of the base material 22. The main body 25 positioned inside is pressed. For this function, the surface 22a on which the riding-up portion 26 is located contributes to a discontinuous surface (here, a flat surface) with the side surface (inner surface) 23c of the recess 23. In addition, since a plurality of the riding-up portions 26 are provided so as to face each other with the concave portion 23 interposed therebetween and surround the concave portion 23, the main body portion 25 is uniformly pressed from the periphery. Thereby, peeling of the shaping | molding layer 24 from the base material 22 can be prevented reliably.

Further, in the mirror element 20, the shrinkage and expansion of the molding layer 24 due to temperature change during use is absorbed by the climbing portion 26 located on the surface 22 a of the base material 22, and the concave portion 23 of the base material 22. The contraction and expansion of the main body portion 25 located inside are alleviated. In addition, since a plurality of the ride-up portions 26 are provided so as to face each other with the recess 23 interposed therebetween and surround the recess 23, the contraction and expansion of the main body portion 25 are alleviated uniformly. Thereby, the deformation of the curved surface 24b of the main body portion 25 can be reliably prevented, and further, the deformation of the optical function portion 21 provided on the curved surface 24b can be reliably prevented.

Further, in the mirror element 20, since the reflection film 27 having a surface that becomes the optical function unit 21 that is a mirror is formed on the curved surface 24b so as to remove the center of the curved surface 24b, the zero-order light becomes stray light. Can be suppressed. Even if the light incident slit 12 and the transmissive grating element 13 are opposed to the curved surface 24b so as to remove the center of the curved surface 24b, it is possible to suppress the 0th-order light from becoming stray light.

In the mirror element 20, the inner surface of the recess 23 formed on the surface 22 a of the substrate 22 may be a curved surface such as a continuous curved surface. Further, the curved surface 24 b of the molding layer 24 on which the optical function unit 21 is provided does not need to reach the riding-up unit 26 from the main body 25 as long as it is formed at least on the main body 25. Conversely, the optical function unit 21 may reach from the main body unit 25 to the riding-up unit 26. Moreover, when the riding-up part 26 opposes on both sides of the recessed part 23, the direction to oppose is arbitrary. Moreover, only one set of the riding-up portions 26 may be provided so as to face each other with the recess 23 interposed therebetween. Further, a plurality of the ride-up portions 26 may be provided so as to surround the recess 23 without being opposed to each other with the recess 23 interposed therebetween, for example, arranged every 120 °. Further, the ride-up portion 26 may be continuous on the surface 22 a of the base material 22.

Further, as shown in FIG. 2, the bottom surface 3b of the cavity 3 of the package body 2 may be formed in a curved shape, and a reflective film (reflecting portion) 32 may be formed on the bottom surface 3b instead of the mirror element 20. . Also in this case, the curvature of the curved surface of the package is changed according to the wavelength range of the light to be detected, as compared with the case where the reflection type grating is provided on the curved surface which is the predetermined inner surface of the package as in the conventional spectral module. In addition, the necessity of forming the curved surface of the package with a predetermined curvature with high accuracy is reduced. Therefore, the package body 2 can be shared and the cost of the spectral module 1 can be reduced as compared with the conventional spectral module.
[Second Embodiment]

The spectral module 1 shown in FIG. 3 is mainly different from the spectral module 1 shown in FIG. 1 in that a light incident slit (light incident portion) 33 is formed in the light detection element 15. Hereinafter, the spectral module of the second embodiment will be described focusing on this difference.

As shown in FIG. 3, a light incident slit 33 is formed on the substrate 15b of the light detecting element 15 so as to be arranged in parallel with the light detecting portion 15a. The light incident slit 33 is formed in the substrate 15b by etching or the like while being positioned with high accuracy with respect to the light detection unit 15a. The light detection unit 15 a and the light incident slit 33 are opposed to the light passage hole 16 of the support substrate 11. Note that a plurality of the light passage holes 16 may be provided in the support substrate 11 so as to face the light detection unit 15a and the light incident slit 33, respectively.

The transmission type grating element 13 is arranged on the cavity 3 side with respect to the support substrate 11 so as to face the light incident slit 33 of the light detection element 15. The transmissive grating element 13 is fixed to the support substrate 11 with the light incident surface 13 a facing the light passage hole 16. That is, the transmissive grating element 13 is directly supported by the support substrate 11.

In the spectroscopic module 1 configured as described above, the light L incident from the outside of the cavity 3 through the light incident hole 8, the window member 9, the light incident slit 33, and the light passing hole 16 is spectrally separated by the transmissive grating element 13. And transmitted to the bottom surface 3 b side of the cavity 3. The light L dispersed by the transmissive grating element 13 is reflected by the mirror element 20 to the support substrate 11 side. The light L reflected by the mirror element 20 enters the light detection unit 15 a through the light passage hole 16. As a result, the electrical signal output from the light detection element 15 is taken out of the spectroscopic module 1 via the bump 18, the wiring 17, the wire 31 and the lead 19.

As described above, in the spectroscopic module 1, the transmission grating element 13 and the light detection element 15 are formed by the package lid 7 that allows the light L to pass from the outside of the cavity 3 into the cavity 3 and the support substrate 11 of the support substrate 11. It is supported. Therefore, it is possible to suppress changes in the spectral characteristics of the transmissive grating element 13 due to the state of the package body 2 (formation accuracy, shrinkage and expansion due to temperature changes during use, etc.). Furthermore, even if the transmissive grating element 13, the mirror element 20, and the light detecting element 15 are arranged close to each other, the light of the transmissive grating element 13 can be compared with the case where the transmissive grating element 13 is supported by the package body 2. It is possible to suppress the light reflected by the incident surface 13a from being detected by the light detection element as stray light. Therefore, according to the spectroscopic module 1, it is possible to prevent a decrease in reliability due to a change in spectral characteristics while achieving miniaturization.

In addition, the light detection element 15 is provided with a light incident slit 33 so as to be positioned upstream of the transmission type grating element 13 (that is, upstream in the traveling direction of the light L). As a result, the light L can be selectively and reliably incident on a predetermined position of the transmissive grating element 13.

As shown in FIG. 4, the bottom surface 3 b of the cavity 3 of the package body 2 may be formed in a curved shape, and the reflective film 32 may be formed on the bottom surface 3 b instead of the mirror element 20. Also in this case, the package body 2 can be shared and the cost of the spectral module 1 can be reduced as compared with the conventional spectral module.
[Third Embodiment]

The spectral module 1 shown in FIG. 5 is different in that the transmission grating element 13 is fixed to the package lid 7 and the light emission aperture (light emission part) 34 is formed on the support substrate 11. This is mainly different from the spectroscopic module 1 shown in FIG. Hereinafter, the spectral module of the third embodiment will be described focusing on this difference.

As shown in FIG. 5, on the opposite side of the cavity 3 with respect to the package lid 7, a movable member 35 in which a light incident slit 12 is formed is disposed. The movable member 35 is airtightly attached to the package lid 7 so that the light incident slit 12 can move within the range of the light incident holes 8 facing each other. A transmissive grating element 13 is disposed on the cavity 3 side with respect to the package lid 7. The transmissive grating element 13 is airtightly fixed to the package lid 7 so as to cover the light incident hole 8 with the light incident surface 13 a facing the light incident hole 8. That is, the transmissive grating element 13 is directly supported by the package lid 7. The support substrate 11 is formed with a light exit aperture 34 that allows a part of the light L dispersed by the transmission type grating element 13 to pass therethrough.

The package lid 7 is supported on the support substrate 11 via the side wall member 36. The cavity 3 is hermetically sealed against the outside air by the package body 2, the package lid 7, the transmission type grating element 13, and the side wall member 36. A partition member 37 is erected between the package lid 7 and the support substrate 11. The partition member 37 separates the region where the grating element 13 is disposed from the region where the light detection element 15 is disposed.

In the spectroscopic module 1 configured as described above, the light L incident from the outside of the cavity 3 through the light incident slit 12 and the light incident hole 8 is dispersed by the transmissive grating element 13 and also on the bottom surface 3b side of the cavity 3. Permeated. Of the light L dispersed by the transmissive grating element 13, the light L that has passed through the light exit aperture 34 is reflected by the reflective film 32 toward the support substrate 11. The light L reflected by the reflective film 32 enters the light detection unit 15 a through the light passage hole 16. As a result, the electrical signal output from the light detection element 15 is taken out of the spectroscopic module 1 via the bump 18, the wiring 17, the wire 31 and the lead 19.

As described above, in the spectroscopic module 1, the transmission type grating element 13 is supported by the package lid 7 that allows the light L to pass from the outside of the cavity 3 into the cavity 3 and the package lid 7 of the support substrate 11. The photodetecting element 15 is supported by the support substrate 11 among them. Therefore, it is possible to suppress changes in the spectral characteristics of the transmissive grating element 13 due to the state of the package body 2 (formation accuracy, shrinkage and expansion due to temperature changes during use, etc.). Further, even if the transmissive grating element 13, the reflective film 32, and the light detecting element 15 are arranged close to each other, the light of the transmissive grating element 13 is lighter than when the transmissive grating element 13 is supported by the package body 2. It is possible to suppress the light reflected by the incident surface 13a from being detected by the light detection element as stray light. Therefore, according to the spectroscopic module 1, it is possible to prevent a decrease in reliability due to a change in spectral characteristics while achieving miniaturization.

Further, the package lid 7 is provided with a light incident slit 12 so as to be positioned in front of the transmissive grating element 13 (that is, upstream in the traveling direction of the light L). As a result, the light L can be selectively and reliably incident on a predetermined position of the transmissive grating element 13.

Further, the support substrate 11 is provided with a light emitting aperture 34 so as to be positioned downstream of the transmissive grating element 13 (that is, downstream of the light L in the traveling direction) and upstream of the reflective film 32. . Accordingly, it is possible to cut only the 0th-order light and unnecessary diffracted light out of the light L dispersed by the transmissive grating element 13 and pass only the light L to be detected.

Furthermore, the light incident slit 12 is configured to move relative to the transmissive grating element 13. Therefore, as shown in FIGS. 5A and 5B, if the position of the light entrance slit 12 is changed, the traveling direction of the light L that can pass through the light exit aperture 34, that is, the wavelength, is changed. The wavelength range of the light L can be changed. If at least one of the light entrance slit 12 and the light exit aperture 34 is configured to move relative to the transmissive grating element 13, the wavelength range of the light L to be detected can be changed.

Although the first to third embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, instead of the light incident slit 12, a light guide member such as an optical fiber may be connected to the position, or an optical member such as a lens may be disposed at that position. Further, the support substrate 11 may be formed of a light transmissive material. In that case, an opening corresponding to the light incident slit 12, the light passage hole 16, the light emission aperture 34, and the like may be formed by patterning the light absorption layer 42 or the like. The material and shape of each component of the spectroscopic module 1 are not limited to the materials and shapes described above, and various materials and shapes can be applied.

DESCRIPTION OF SYMBOLS 1 ... Spectroscopic module, 2 ... Package main body (accommodating member), 3 ... Cavity, 3b ... Bottom surface (inner surface), 7 ... Package lid (light passage member), 11 ... Support substrate (light passage member), 12 ... Light entrance slit (Light incident part), 13 ... transmission grating element (spectral part), 15 ... light detection element, 20 ... mirror element (reflection part), 21 ... optical function part, 22 ... base material, 22a ... surface, 23 ... concave part 23b ... bottom surface (inner surface), 24 ... molded layer, 24b ... curved surface (predetermined surface), 25 ... main body portion (first portion), 26 ... riding portion (second portion), 32 ... reflection film ( Reflecting part), 33... Light incident slit (light incident part), 34... Light emitting aperture (light emitting part).

Claims

A housing member formed with a cavity;
A light-passing member attached to the housing member so as to face the inner surface of the cavity and allowing light to pass from the outside of the cavity into the cavity;
A spectroscopic unit that is supported by the light passing member and that splits light incident from outside the cavity and transmits the light to the inner surface side of the cavity;
A reflective part that is disposed on the inner surface of the cavity and reflects light dispersed by the spectroscopic part;
A spectroscopic module comprising: a light detecting element that is supported by the light passing member and detects light reflected by the reflecting portion.
The spectroscopic module according to claim 1, wherein the light passing member or the light detection element is provided with a light incident portion so as to be positioned in front of the spectroscopic portion.
3. The spectroscopic module according to claim 2, wherein the light passing member is provided with a light emitting part so as to be located at a subsequent stage of the spectroscopic part and at a preceding stage of the reflecting part.
4. The spectroscopic module according to claim 3, wherein at least one of the light incident part and the light emitting part is configured to move relative to the spectroscopic part.
The spectroscopic module according to any one of claims 1 to 4, wherein the cavity is hermetically sealed against outside air.
The reflecting portion is a mirror element disposed on the inner surface of the cavity;
The mirror element is
A base material having a recess formed on the surface;
A molding layer disposed on the substrate,
The molding layer is a first part located in the concave part when viewed from the depth direction of the concave part, and a second part located on the surface of the base material in a state of being connected to the first part. The part of
The spectroscopic module according to any one of claims 1 to 5, wherein an optical function portion that is a mirror is provided on a predetermined surface of the first portion that faces the inner surface of the recess.