Filter Device

Abstract

A filter device that enables highly sensitive and highly accurate detection is provided. [Solution] The filter device includes a package (2) having a window (15), a bandpass filter (14) disposed on the inner surface of the package (2), and a Fabry-Perot interference filter (10A) disposed within the package (2). When viewed from the direction of light incidence, the outer edge of the bandpass filter (14) is located outside the outer edge of the Fabry-Perot interference filter (10A). The Fabry-Perot interference filter (10A) includes a substrate, a first layer structure disposed on a first surface of the substrate facing the window (15), and a lens portion integrally provided on a second surface of the substrate opposite the window (15). The first layer structure includes a first laminate including a first mirror portion, an intermediate layer forming a gap, and a second laminate including a second mirror portion. When viewed from the direction of light incidence, the lens portion is located inside the gap.

Description

[Technical field]

[0001] The present invention relates to a filter device comprising a Fabry-Perot interference filter. [Background technology]

[0002] There is known a light detection device that includes a package with a window, a Fabry-Perot interference filter within the package that transmits light incident through the window, and a light detector within the package that detects the light that has transmitted through the Fabry-Perot interference filter (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-211860 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned photodetection device, it is desirable that the light transmitted through the Fabry-Perot interference filter is efficiently detected by the photodetector. In particular, when a general-purpose light source is used to analyze the reflected light from the object to be measured, the amount of reflected light tends to be small, so it is important to detect the light efficiently.

[0005] In order to detect light efficiently, it is conceivable to use a photodetector such as a photodiode with a large light receiving area, but if a photodetector with a large light receiving area is used, there is a risk that the noise component in the signal output from the photodetector will become large.

[0006] An object of the present invention is to provide a light detection device capable of highly sensitive and highly accurate detection. [Means for solving the problem]

[0007] The photodetection device of the present invention comprises a package having a window portion through which light is incident, a Fabry-Perot interference filter disposed within the package and transmitting the light incident through the window portion, and a photodetector disposed within the package at a distance from the Fabry-Perot interference filter and detecting the light transmitted through the Fabry-Perot interference filter. The Fabry-Perot interference filter has a substrate having a first surface on the window portion side and a second surface on the photodetector side, a first layer structure disposed on the first surface and provided with a first mirror portion and a second mirror portion that face each other via a gap and have a variable distance between them, and a lens portion integrally provided on the second surface side and that focuses the light transmitted through the first mirror portion and the second mirror portion onto the photodetector.

[0008] In the above-mentioned photodetector, the Fabry-Perot interference filter has a lens portion that focuses the light transmitted through the first mirror portion and the second mirror portion on the photodetector. This allows the light transmitted through the first mirror portion and the second mirror portion to be efficiently incident on the photodetector even when a photodetector with a small light receiving area is used. In other words, the light transmitted through the Fabry-Perot interference filter can be efficiently detected using a photodetector with a small light receiving area while reducing noise components in the signal output from the photodetector. Here, when the light receiving area of ​​the photodetector becomes small, high accuracy is required for the position of the lens portion relative to the photodetector (particularly, the position in the direction perpendicular to the optical axis). In the above-mentioned photodetector, since the lens portion is located behind the first mirror portion and the second mirror portion, the distance between the lens portion and the photodetector is smaller than when the lens portion is located in front of the first mirror portion and the second mirror portion, and the accuracy required for the position of the lens portion relative to the photodetector is relaxed. Furthermore, because the lens portion is integrally provided on the second surface side of the substrate constituting the Fabry-Perot interference filter, the position of the lens portion relative to the photodetector is less likely to shift compared to when the lens portion is attached separately from the Fabry-Perot interference filter to a support member (for example, a support member that supports the Fabry-Perot interference filter in a package with the Fabry-Perot interference filter separated from the photodetector). As a result, the above-mentioned photodetector enables highly sensitive and highly accurate detection.

[0009] In the photodetector of the present invention, the lens portion may be formed on the second surface side of the substrate. In this configuration, since there is no interface between the substrate and the lens portion, optical loss can be suppressed and peeling of the lens portion can be prevented. Furthermore, the lens portion can be easily formed with high positional accuracy in the semiconductor manufacturing process.

[0010] In the photodetector of the present invention, the lens portion may be provided directly or indirectly on the second surface. This configuration can improve the stress balance of the Fabry-Perot interference filter compared to when the lens portion is formed on a part of the substrate. In addition, the degree of freedom of the shape that the lens portion can take (such as the curvature of the lens surface) can be increased.

[0011] In the photodetector of the present invention, the Fabry-Perot interference filter further includes a second layer structure disposed on the second surface and configured to correspond to the first layer structure, and the second layer structure has an opening through which light transmitted through the first mirror section and the second mirror section passes, and the lens section may be disposed within the opening. With this configuration, even if the lens section is separate from the substrate, it is possible to prevent the position of the lens section from being shifted. In addition, while preventing the thickness of the Fabry-Perot interference filter from increasing, for example, the thickness of the lens section is increased by the amount of the lens section disposed within the opening, thereby improving the light-collecting function of the lens section. Furthermore, by disposing the entire lens section within the opening, it is possible to prevent the lens section from being damaged or contaminated.

[0012] In the photodetector of the present invention, the Fabry-Perot interference filter further includes a second layer structure disposed on the second surface and configured to correspond to the first layer structure, and the second layer structure has an opening through which light transmitted through the first mirror section and the second mirror section passes, and the lens section may be attached to the second layer structure so as to cover the opening. With this configuration, the stress balance between the first surface side and the second surface side of the substrate can be improved in the Fabry-Perot interference filter. In addition, the degree of freedom of the shape (curvature of the lens surface, etc.) that the lens section 50 can take can be increased.

[0013] In the photodetector of the present invention, when viewed from the direction of light incidence, the outer edge of the lens portion may be located inside the outer edge of the window portion and outside the outer edge of the light receiving area of ​​the photodetector. With this configuration, light transmitted through the first mirror portion and the second mirror portion can be efficiently incident on the light receiving area of ​​the photodetector. Effect of the Invention

[0014] According to the present invention, it is possible to provide a light detection device capable of highly sensitive and highly accurate detection. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of a photodetector according to a first embodiment. [Diagram 2] FIG. 2 is a plan view of the light detection device shown in FIG. [Diagram 3] 2 is a plan view of a Fabry-Perot interference filter of the photodetector shown in FIG. 1. [Figure 4] 4 is a cross-sectional view of the Fabry-Perot interference filter taken along line IV-IV shown in FIG. 3. [Diagram 5] FIG. 5 is a cross-sectional view of a modified example of the Fabry-Perot interference filter shown in FIG. [Figure 6] FIG. 11 is a cross-sectional view of a photodetector according to a second embodiment. [Figure 7] 7 is a cross-sectional view of a Fabry-Perot interference filter of the photodetector shown in FIG. 6. [Figure 8] FIG. 8 is a cross-sectional view of a modified example of the Fabry-Perot interference filter shown in FIG. [Figure 9] FIG. 11 is a cross-sectional view of a photodetector according to a third embodiment. [Figure 10] 10 is a cross-sectional view of a Fabry-Perot interference filter of the photodetector shown in FIG. 9. [Figure 11] FIG. 11 is a cross-sectional view of a modified example of the Fabry-Perot interference filter shown in FIG. [Figure 12] FIG. 11 is a cross-sectional view of a modified example of the Fabry-Perot interference filter shown in FIG. [Figure 13] FIG. 11 is a cross-sectional view of a modified example of the Fabry-Perot interference filter shown in FIG. [Figure 14] FIG. 11 is a cross-sectional view of a modified example of the Fabry-Perot interference filter shown in FIG. [Figure 15] FIG. 11 is a cross-sectional view of a modified example of the Fabry-Perot interference filter shown in FIG. [Figure 16] FIG. 1 is a cross-sectional view of a reference example of a Fabry-Perot interference filter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and duplicated parts are omitted. [First embodiment] [Configuration of the photodetector]

[0017] 1, the photodetector 1A includes a package 2. The package 2 is a CAN package having a stem 3 and a cap 4. The cap 4 is integrally formed of a side wall 5 and a top wall 6. The top wall 6 faces the stem 3 in a direction parallel to a line L. The stem 3 and the cap 4 are made of, for example, metal, and are hermetically joined to each other.

[0018] A wiring board 7 is fixed to the inner surface 3a of the stem 3 by, for example, an adhesive. Examples of the substrate material of the wiring board 7 include silicon, ceramic, quartz, glass, and plastic. A photodetector 8 and a temperature compensation element (not shown) such as a thermistor are mounted on the wiring board 7. The photodetector 8 is arranged on a line L in the package 2. More specifically, the photodetector 8 is arranged in the package 2 so that the center line of the light receiving area coincides with the line L. The photodetector 8 is an infrared detector such as a quantum sensor using InGaAs or a thermal sensor using a thermopile or a bolometer. When detecting light in each wavelength range of ultraviolet, visible, and near-infrared, for example, a silicon photodiode or the like can be used as the photodetector 8. The light receiving area of ​​the photodetector 8 may be composed of one light receiving unit, or may be composed of multiple light receiving units. The photodetector 8 having a light receiving area composed of a plurality of light receiving parts is, for example, a photodiode array, a CCD image sensor, a CMOS image sensor, etc. Furthermore, a plurality of photodetectors 8 may be mounted on the wiring board 7. In this case, the collection of the light receiving parts of the plurality of photodetectors 8 can be regarded as the light receiving area.

[0019] A plurality of spacers (supporting parts) 9 are fixed on the wiring board 7, for example, by adhesive. The plurality of spacers 9 are arranged in the package 2 so as to sandwich or surround the photodetector 8 and the temperature compensation element. The material of each spacer 9 may be, for example, silicon, ceramic, quartz, glass, plastic, or the like. The Fabry-Perot interference filter 10A is fixed on the plurality of spacers 9, for example, by adhesive. The Fabry-Perot interference filter 10A is arranged on a line L in the package 2. More specifically, the Fabry-Perot interference filter 10A is arranged in the package 2 so that the center line of the light transmission region 10a thereof coincides with the line L. The spacer 9 supports the Fabry-Perot interference filter 10A in a state where the Fabry-Perot interference filter 10A is separated from the photodetector 8 (i.e., in a state where a space is formed between the Fabry-Perot interference filter 10A and the photodetector 8). That is, the Fabry-Perot interference filter 10A and the photodetector 8 are arranged in the package 2 in a state where they are separated from each other. The spacer 9 may be integrally formed with the wiring board 7. The Fabry-Perot interference filter 10A may be supported by one spacer 9, not by a plurality of spacers 9. The spacer 9 may be integrally formed with the Fabry-Perot interference filter 10A.

[0020] A plurality of lead pins 11 are fixed to the stem 3. More specifically, each lead pin 11 penetrates the stem 3 while maintaining electrical insulation and airtightness between the lead pin 11 and the stem 3. Each lead pin 11 is electrically connected to an electrode pad provided on the wiring board 7, a terminal of the photodetector 8, a terminal of the temperature compensation element, and a terminal of the Fabry-Perot interference filter 10A by a wire 12. This allows input and output of electrical signals to and from each of the photodetector 8, the temperature compensation element, and the Fabry-Perot interference filter 10A.

[0021] The package 2 has an opening 2a. More specifically, the opening 2a is formed in the top wall 6 of the cap 4 so that its center line coincides with the line L. A light-transmitting member 13 is disposed on the inner surface 6a of the top wall 6 so as to close the opening 2a. The light-transmitting member 13 extends into the opening 2a and to the inner surface 5a of the side wall 5, and hermetically seals the opening 2a. The light-transmitting member 13 transmits at least light in the measurement wavelength range of the light detection device 1A. The light-incident surface 13a of the light-transmitting member 13 is substantially flush with the outer surface of the top wall 6 in the opening 2a. Such a light-transmitting member 13 is formed by disposing a glass pellet inside the cap 4 with the opening 2a facing downward and melting the glass pellet. That is, the light-transmitting member 13 is made of fused glass. In the package 2, the portion of the light-transmitting member 13 located in the opening 2a functions as a window portion 15 that allows light to enter the package 2 from the outside. For example, a plate-like light-transmitting member 13 made of glass, quartz, silicon, germanium, plastic, or the like may be airtightly joined to the inner surface 6a of the top wall 6 so as to close the opening 2a. In this case, the area within the opening 2a functions as the window portion 15. In other words, the area within the opening 2a functions as the window portion 15 regardless of the presence or absence of the light-transmitting member 13.

[0022] A plate-shaped bandpass filter 14 is fixed to the light exit surface 13b of the light transmitting member 13 (the surface facing the light entrance surface 13a in the direction parallel to the line L) by, for example, an adhesive. The bandpass filter 14 selectively transmits light in the measurement wavelength range of the light detection device 1A. The bandpass filter 14 has a dielectric multilayer film made of, for example, a combination of a high refractive index material such as TiO2 or Ta2O5 and a low refractive index material such as SiO2 or MgF2. The bandpass filter 14 may be formed on the light exit surface 13b of the light transmitting member 13 by, for example, deposition or the like.

[0023] The positional relationship and size relationship of each part when viewed from a direction parallel to the line L (the direction of incidence of light to the window part 15) are as follows. As shown in FIG. 2, the center line of the window part 15 (i.e., the center line of the opening 2a), the center line of the light transmitting member 13, the center line of the bandpass filter 14, the center line of the light transmitting region 10a of the Fabry-Perot interference filter 10A, and the center line of the light receiving region 8a of the photodetector 8 coincide with the line L. The outer edge of the window part 15, the outer edge of the light transmitting member 13, the outer edge of the light transmitting region 10a, and the outer edge of the light receiving region 8a are, for example, circular. The outer edge of the bandpass filter 14, the outer edge of the Fabry-Perot interference filter 10A, and the outer edge of the photodetector 8 are, for example, rectangular.

[0024] The outer edge of the window portion 15 (i.e., the inner edge of the opening 2a) is located inside the outer edge of the light transmitting member 13, the outer edge of the bandpass filter 14, and the outer edge of the Fabry-Perot interference filter 10A, and is located outside the outer edge of the light transmitting region 10a and the outer edge of the light receiving region 8a. The outer edge of the light receiving region 8a is located inside the outer edge of the light transmitting region 10a. The outer edge of the bandpass filter 14 is located inside the outer edge of the light transmitting member 13, and outside the outer edge of the Fabry-Perot interference filter 10A. Note that "one outer edge is located inside the other outer edge when viewed from a predetermined direction" means "the other outer edge surrounds the one outer edge when viewed from a predetermined direction" or "the other outer edge includes the one outer edge when viewed from a predetermined direction". Also, "one outer edge is located outside the other outer edge when viewed from a predetermined direction" means "one outer edge surrounds the other outer edge when viewed from a predetermined direction" or "one outer edge includes the other outer edge when viewed from a predetermined direction".

[0025] In the photodetector 1A configured as above, when light is incident from the outside onto the light transmission region 10a of the Fabry-Perot interference filter 10A via the window portion 15, the light transmission member 13, and the bandpass filter 14, light having a predetermined wavelength is selectively transmitted. The light transmitted through the light transmission region 10a of the Fabry-Perot interference filter 10A enters the light receiving region 8a of the photodetector 8 and is detected by the photodetector 8. [Fabry-Perot interference filter configuration]

[0026] As shown in FIG. 3 and FIG. 4, in the Fabry-Perot interference filter 10A, a light-transmitting region 10a that transmits light according to the distance between the first mirror portion and the second mirror portion is provided on the line L. The light-transmitting region 10a is, for example, a cylindrical region. In the light-transmitting region 10a, the distance between the first mirror portion and the second mirror portion is controlled with extremely high precision. In other words, the light-transmitting region 10a is a region in the Fabry-Perot interference filter 10A where the distance between the first mirror portion and the second mirror portion can be controlled to a predetermined distance in order to selectively transmit light having a predetermined wavelength, and is a region through which light having a predetermined wavelength according to the distance between the first mirror portion and the second mirror portion can transmit.

[0027] The Fabry-Perot interference filter 10A includes a rectangular plate-shaped substrate 21. 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 window portion 15 side (i.e., the light incident side). The second surface 21b is the surface on the photodetector 8 side (i.e., the light exit side). A first layer structure 30 is disposed on the first surface 21a. A second layer structure 40 is disposed on the second surface 21b.

[0028] The first layer structure 30 is configured 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. Between the first stack 32 and the second stack 34, an air gap S is formed by the frame-shaped first intermediate layer 33. The substrate 21 is made of, for example, silicon, quartz, glass, or the like. When the substrate 21 is made of silicon, the first antireflection layer 31 and the first intermediate layer 33 are made of, for example, silicon oxide. The thickness of the first intermediate layer 33 is, for example, several tens of nm to several tens of μm.

[0029] The portion of the first laminate 32 that corresponds to the light transmitting region 10a functions as the first mirror section 35. The first laminate 32 is configured by alternately laminating a plurality of polysilicon layers and a plurality of silicon nitride layers. The optical thickness of each of the polysilicon layers and silicon nitride layers that constitute the first mirror section 35 is preferably an integral multiple of ¼ of the central transmission wavelength. The first mirror section 35 may be disposed directly on the first surface 21a without the first antireflection layer 31 being interposed therebetween.

[0030] A portion of the second laminate 34 corresponding to the light transmitting region 10a functions as a second mirror section 36. The second mirror section 36 faces the first mirror section 35 across a gap S in a direction parallel to the line L. The second laminate 34 is formed by alternately stacking a plurality of polysilicon layers and a plurality of silicon nitride layers one by one. The optical thickness of each of the polysilicon layers and silicon nitride layers constituting the second mirror section 36 is preferably an integer multiple of ¼ of the central transmission wavelength.

[0031] 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 to the above-mentioned materials, titanium oxide, tantalum oxide, zirconium oxide, magnesium fluoride, aluminum oxide, calcium fluoride, silicon, germanium, zinc sulfide, etc. may be used as the material of each layer constituting the first stack 32 and the second stack 34.

[0032] In the portion of the second laminate 34 corresponding to the void S, a plurality of through holes 34b are formed from a surface 34a of the second laminate 34 opposite to the first intermediate layer 33 to the void S. The plurality of through holes 34b are formed to an extent that does not substantially affect the function of the second mirror section 36. The plurality of through holes 34b are used to form the void S by removing a part of the first intermediate layer 33 by etching.

[0033] The first mirror section 35 has a first electrode 22 formed so as to surround the light transmitting region 10a. The first mirror section 35 has a second electrode 23 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 of the first stack 32 that is closest to the gap S to reduce resistance. The second mirror section 36 has a third electrode 24 formed. The third electrode 24 faces the first electrode 22 and the second electrode 23 through the gap S in a direction parallel to the line L. The third electrode 24 is formed by doping impurities into the polysilicon layer of the second stack 34 that is closest to the gap S to reduce resistance. The size of the second electrode 23 is preferably a size that includes the entire light transmitting region 10a, but may be approximately the same as the size of the light transmitting region 10a.

[0034] The first layer structure 30 is provided with a pair of first terminals 25 and a pair of second terminals 26. The pair of first terminals 25 face each other with the light transmission region 10a in between. Each first terminal 25 is disposed in a through hole extending from the surface 34a of the second laminate 34 to the first laminate 32. Each first terminal 25 is electrically connected to the first electrode 22 via the wiring 22a. The pair of second terminals 26 face each other with the light transmission region 10a in between 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 laminate 34 to the inside of the first intermediate layer 33. Each second terminal 26 is electrically connected to the second electrode 23 via the wiring 23a and is electrically connected to the third electrode 24 via the wiring 24a.

[0035] The first laminate 32 has trenches 27 and 28 on its surface 32a on the side of the first intermediate layer 33. The trench 27 extends in an annular shape so as to surround the connection portion of the wiring 23a with the second terminal 26. The trench 27 electrically insulates the first electrode 22 from the wiring 23a. The trench 28 extends in an annular shape along the inner edge of the first electrode 22. The trench 28 electrically insulates the first electrode 22 from the inner region of the first electrode 22 (i.e., the region where the second electrode 23 exists). The second laminate 34 has trenches 29 on its surface 34a. The trench 29 extends in an annular shape so as to surround the first terminal 25. The trench 29 electrically insulates the first terminal 25 from the third electrode 24. The regions in the trenches 27, 28, and 29 may be insulating materials or voids.

[0036] The second layer structure 40 is configured by stacking the second antireflection layer 41, the third stack 42, the second intermediate layer 43, and the fourth stack 44 in this order on the second surface 21b. The second antireflection layer 41, the third stack 42, the second intermediate layer 43, and the fourth stack 44 have the same configurations as the first antireflection layer 31, the first stack 32, the first intermediate layer 33, and the second stack 34, respectively. In this way, the second layer structure 40 has a stack structure symmetrical to the first layer structure 30 with respect to the substrate 21. That is, the second layer structure 40 is configured to correspond to the first layer structure 30. The second layer structure 40 has a function of suppressing warping of the substrate 21, etc.

[0037] An opening 40a is formed in the third laminate 42, the second intermediate layer 43, and the fourth laminate 44 so as to include the light transmitting region 10a. The center line of the opening 40a coincides with the line L. The opening 40a is, for example, a cylindrical region and has approximately the same diameter as the light transmitting region 10a. The opening 40a is open to the light exit side, and the bottom surface of the opening 40a reaches the second anti-reflection layer 41. The opening 40a passes light that has passed through the first mirror portion 35 and the second mirror portion 36.

[0038] A light-shielding layer 45 is formed on the surface of the fourth stack 44 on the light-emitting side. The light-shielding layer 45 is made of, for example, aluminum. A protective layer 46 is formed on the surface of the light-shielding layer 45 and the inner surface of the opening 40a. The protective layer 46 is made of, for example, aluminum oxide. By setting the thickness of the protective layer 46 to 1 to 100 nm (preferably, about 30 nm), the optical influence of the protective layer 46 can be ignored.

[0039] A lens section 50 is integrally provided on the second surface 21b side of the substrate 21. The lens section 50 is formed on the portion of the substrate 21 on the second surface 21b side. A light exit surface 50a of the lens section 50 is formed by a part of the second surface 21b. The center line of the lens section 50 (i.e., the center line of the light exit surface 50a) coincides with the line L. When viewed from a direction parallel to the line L, the outer edge of the lens section 50 is located inside the outer edge of the window section 15 of the package 2 and outside the outer edge of the light receiving area 8a of the photodetector 8 (see FIG. 2). Here, the lens section 50 has approximately the same diameter as the light transmitting area 10a. The light exit surface 50a is covered by the second antireflection layer 41 and the protective layer 46 at the bottom surface of the opening 40a. The lens section 50 focuses the light transmitted through the first mirror section 35 and the second mirror section 36 on the light receiving area 8a of the photodetector 8.

[0040] The lens portion 50 is configured as a Fresnel lens. As an example, the diameter of the lens portion 50 is about 750 μm, and when the substrate 21 is made of silicon, the refractive index of the lens portion 50 is 3.5. The number of circles in the Fresnel lens is 3 to 60, the height of the unevenness is 1 to 25 μm, and the distance between the circles is 5 to 150 μm. Such a lens portion 50 is formed by patterning a resist on the second surface 21b of the substrate 21 using a 3D mask or the like, and etching back the resist.

[0041] 5, the lens portion 50 may be configured as a convex lens having a light exit surface 50a convex on the light exit side. As an example, the diameter of the lens portion 50 is about 750 μm, and when the substrate 21 is made of silicon, the refractive index of the lens portion 50 is 3.5. The height of the light exit surface 50a convex on the light exit side is 60 to 80 μm. Such a lens portion 50 is formed by patterning a resist on the second surface 21b of the substrate 21 using a 3D mask or the like, and etching back the resist.

[0042] In the Fabry-Perot interference filter 10A configured as above, when a voltage is applied between the first electrode 22 and the third electrode 24 via the pair of first terminals 25 and the pair of second terminals 26, an electrostatic force corresponding to the voltage is generated between the first electrode 22 and the third electrode 24. The electrostatic force attracts the second mirror portion 36 toward 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 is adjusted. In this way, in the Fabry-Perot interference filter 10A, the distance between the first mirror portion 35 and the second mirror portion 36 is variable.

[0043] The wavelength of light transmitted through the Fabry-Perot interference filter 10A depends on the distance between the first mirror portion 35 and the second mirror portion 36 in the light transmission region 10a. Therefore, the wavelength of the transmitted light can be appropriately selected by adjusting the voltage applied between the first electrode 22 and the third electrode 24. At this time, the second electrode 23 has the same potential as the third electrode 24. Therefore, the second electrode 23 functions as a compensation electrode for keeping the first mirror portion 35 and the second mirror portion 36 flat in the light transmission region 10a.

[0044] In the photodetector 1A, for example, a spectrum can be obtained by detecting light transmitted through the light transmission region 10a of the Fabry-Perot interference filter 10A in the photodetector 8 while changing the voltage applied to the Fabry-Perot interference filter 10A (i.e., while changing the distance between the first mirror portion 35 and the second mirror portion 36 in the Fabry-Perot interference filter 10A). At this time, in the Fabry-Perot interference filter 10A, the light transmitted through the first mirror portion 35 and the second mirror portion 36 is focused on the light receiving region 8a of the photodetector 8 by the lens portion 50.

[0045] In addition, in the Fabry-Perot interference filter 10A, the light transmitting region 10a (as described above, this is a region of the Fabry-Perot interference filter 10A in which the distance between the first mirror portion 35 and the second mirror portion 36 can be controlled to a predetermined distance in order to selectively transmit light having a predetermined wavelength, and which is a region through which light having a predetermined wavelength according to the distance between the first mirror portion 35 and the second mirror portion 36 can transmit) can be considered to be a region corresponding to the region inside the first electrode 22 (i.e., the region where the second electrode 23 functioning as a compensation electrode is present) when viewed from a direction parallel to the line L, or can be considered to be a region corresponding to the opening 40a when viewed from a direction parallel to the line L. [Action and Effects]

[0046] In the photodetector 1A, the Fabry-Perot interference filter 10A has a lens unit 50 that focuses the light transmitted through the first mirror unit 35 and the second mirror unit 36 ​​on the photodetector 8. This allows the light transmitted through the first mirror unit 35 and the second mirror unit 36 ​​to be efficiently incident on the light-receiving area 8a even when a photodetector 8 with a small light-receiving area 8a is used. In other words, the light transmitted through the Fabry-Perot interference filter 10A can be efficiently detected using a photodetector 8 with a small light-receiving area 8a while reducing noise components in the signal output from the photodetector 8. Here, when the light-receiving area 8a of the photodetector 8 becomes small, high accuracy is required for the position of the lens unit 50 relative to the photodetector 8 (particularly, the position in the direction perpendicular to the optical axis). In the photodetector 1A, the lens unit 50 is located behind the first mirror unit 35 and the second mirror unit 36, so the distance between the lens unit 50 and the photodetector 8 is smaller than when the lens unit 50 is located before the first mirror unit 35 and the second mirror unit 36, and the accuracy required for the position of the lens unit 50 relative to the photodetector 8 is relaxed. In addition, the lens unit 50 is provided integrally with the second surface 21b side of the substrate 21 constituting the Fabry-Perot interference filter 10A, so the position of the lens unit 50 relative to the photodetector 8 is less likely to shift than when the lens unit 50 is attached to the spacer 9 separately from the Fabry-Perot interference filter 10A. As described above, the photodetector 1A enables highly sensitive and highly accurate detection.

[0047] As an example, a case will be described where the diameter of the light transmission region 10a of the Fabry-Perot interference filter 10A is 750 μm and the diameter of the light receiving region 8a of the photodetector 8 is 100 μm. In this case, if the Fabry-Perot interference filter 10A is not provided with a lens portion 50, only a portion of the light transmitted through the light transmission region 10a of the Fabry-Perot interference filter 10A having a diameter of 100 μm enters the light receiving region 8a of the photodetector 8. In other words, only a portion of the light transmitted through the light transmission region 10a of the Fabry-Perot interference filter 10A can be used.

[0048] In contrast, when the lens portion 50 is provided in the Fabry-Perot interference filter 10A, substantially all of the light transmitted through the light transmission region 10a of the Fabry-Perot interference filter 10A is incident on the light receiving region 8a of the photodetector 8. In other words, substantially all of the light transmitted through the light transmission region 10a of the Fabry-Perot interference filter 10A can be utilized. In particular, when a general-purpose light source is used to analyze reflected light from an object to be measured, the amount of reflected light tends to be small, and therefore it is extremely important to detect light efficiently in this manner.

[0049] However, if the diameter of the light receiving region 8a of the photodetector 8 is 100 μm, then the focusing position of the light focused by the lens unit 50 needs to have an accuracy of ±50 μm or less, that is, the position of the lens unit 50 relative to the light receiving region 8a of the photodetector 8 needs to have a similar accuracy. In the Fabry-Perot interference filter 10A, the lens unit 50 is integrally provided on the second surface 21b side of the substrate 21, thereby making it possible to achieve such accuracy.

[0050] In addition, by giving the window 15 of the package 2 a lens function, it is also possible to realize high-sensitivity detection in the light detection device 1A. However, considering the mounting accuracy of the cap 4 on the stem 3, the diameter of the window 15 needs to be sufficiently larger than the diameter of the light transmission region 10a of the Fabry-Perot interference filter 10A, for example, 1500 μm. In addition, the position of the window 15 with respect to the light receiving region 8a of the light detector 8 needs to be accurate to about ±50 μm. Therefore, if active alignment is not performed in mounting the cap 4 on the stem 3, there is a risk that light will not enter the light receiving region 8a of the light detector 8. As such, the lens portion becomes large and active alignment is required, so the configuration in which the window 15 has a lens function has a smaller cost advantage than the configuration in which the lens portion 50 is integrally provided on the second surface 21b side of the substrate 21.

[0051] In addition, in the photodetector 1A, since the lens unit 50 is integrally provided on the second surface 21b side of the substrate 21 constituting the Fabry-Perot interference filter 10A, only the alignment with the photodetector 8 needs to be considered when mounting the Fabry-Perot interference filter 10A. Therefore, assembly can be significantly facilitated compared to a case where the lens unit 50 is attached to the spacer 9 separately from the Fabry-Perot interference filter 10A in a semiconductor manufacturing process. Furthermore, in a case where the Fabry-Perot interference filter 10A is manufactured at the wafer level, the lens unit 50 can also be integrally provided on the second surface 21b side of the substrate 21 at the wafer level, so that a Fabry-Perot interference filter 10A having a small lens unit 50 with high positional accuracy can be easily manufactured.

[0052] In addition, in the photodetector 1A, the lens portion 50 is formed on the portion of the substrate 21 on the second surface 21b side. In this configuration, since there is no interface between the substrate 21 and the lens portion 50, optical loss can be suppressed and peeling of the lens portion 50 can be prevented. Furthermore, in the semiconductor manufacturing process, the lens portion 50 can be easily formed with high positional accuracy. Furthermore, when the substrate 21 is made of silicon, the refractive index of the lens portion 50 is 3.5. In this way, since the lens portion 50 can be formed from a high refractive index material, it is possible to shorten the distance between the photodetector 8 and the Fabry-Perot interference filter 10A and to miniaturize the photodetector 1A. Furthermore, since the light exit surface 50a of the lens portion 50 is located on the bottom surface of the opening 40a, damage and contamination of the light exit surface 50a can be prevented.

[0053] In addition, in the photodetector 1A, when viewed from the light incidence direction, the outer edge of the lens portion 50 is located inside the outer edge of the window portion 15 and outside the outer edge of the light receiving region 8a of the photodetector 8. With this configuration, the light transmitted through the first mirror portion 35 and the second mirror portion 36 can be efficiently incident on the light receiving region 8a of the photodetector 8. For example, it is difficult to obtain such an effect with a configuration in which a lens is integrally provided on the light receiving region 8a of the photodetector 8. By integrally providing the lens portion 50 having a size equal to or larger than the light transmitting region 10a of the Fabry-Perot interference filter 10A on the Fabry-Perot interference filter 10A side, the detection efficiency of the light transmitted through the Fabry-Perot interference filter 10A can be maximized. [Second embodiment]

[0054] As shown in FIG. 6, the photodetector 1B is different from the photodetector 1A described above mainly in the configuration of the Fabry-Perot interference filter 10B. As shown in FIG. 7, in the Fabry-Perot interference filter 10B, the lens unit 50 is configured as a separate body from the substrate 21. The lens unit 50 has a light exit surface 50a convex on the light exit side and a flat light incident surface 50b. The light incident surface 50b of the lens unit 50 is fixed to the surface of the protective layer 46 on the photodetector 8 side with, for example, an adhesive, in a state in which the opening 40a is blocked. That is, the lens unit 50 is attached to the second layer structure 40 so as to block the opening 40a. Note that an optical resin may be used as an adhesive for attaching the lens unit 50 to the second layer structure 40, and the optical resin may be filled in the opening 40a.

[0055] The center line of the lens portion 50 coincides with the line L. When viewed from a direction parallel to the line L, the outer edge of the lens portion 50 is located inside the outer edge of the window portion 15 of the package 2 and outside the outer edge of the light receiving region 8a of the photodetector 8. Here, the lens portion 50 has a diameter larger than that of the light transmitting region 10a. As an example, the diameter of the lens portion 50 is about 1000 μm, and when the lens portion 50 is made of silicon, the refractive index of the lens portion 50 is 3.5. In addition, the height of the light exit surface 50a convex on the light exit side is 50 to 400 μm.

[0056] 8, the lens portion 50 may be configured as a Fresnel lens. As an example, the diameter of the lens portion 50 is about 1000 μm, the thickness of the substrate of the lens portion 50 is 200 μm, and when the lens portion 50 is made of silicon, the refractive index of the lens portion 50 is 3.5. The number of circles in the Fresnel lens is 10 or more, the height of the unevenness is 40 μm or less, and the distance between the circles is 50 μm or less.

[0057] In the photodetector 1B configured as described above, the lens portion 50 is integrally provided on the second surface 21b side of the substrate 21, so that highly sensitive and highly accurate detection is possible, similar to the above-mentioned photodetector 1A.

[0058] In the light detection device 1B, the lens section 50 is attached to the second layer structure 40 so as to block the opening 40a. This configuration can improve the stress balance between the first surface 21a side and the second surface 21b side of the substrate 21 in the Fabry-Perot interference filter 10B. In addition, the degree of freedom of the shape that the lens section 50 can take (such as the curvature of the lens surface of the light exit surface 50a) can be increased. Note that the lens section 50 may be configured not to completely block the opening 40a, and the inside and outside of the opening 40a may be communicated with each other. In this case, the generation of stress due to the expansion and contraction of air in the opening 40a can be suppressed.

[0059] Furthermore, in the photodetector 1B, the lens unit 50 is located between a plurality of spacers 9 (see FIG. 6), and the center of gravity of the Fabry-Perot interference filter 10B is lowered, thereby improving the stability of the Fabry-Perot interference filter 10B.

[0060] Furthermore, when attaching the lens section 50 to the second layer structure 40, the opening 40a can be used as a reference for alignment, so that the lens section 50 can be mounted easily and with high accuracy.

[0061] Furthermore, in the case of manufacturing the Fabry-Perot interference filter 10B at the wafer level in a semiconductor manufacturing process, the lens portion 50 can also be implemented at the wafer level, making it possible to easily manufacture a Fabry-Perot interference filter 10B having a small lens portion 50 with high positional accuracy. [Third embodiment]

[0062] As shown in FIG. 9, the photodetector 1C is different from the photodetector 1A described above mainly in the configuration of the Fabry-Perot interference filter 10C. As shown in FIG. 10, in the Fabry-Perot interference filter 10C, the lens unit 50 is configured separately from the substrate 21. The lens unit 50 is disposed in the opening 40a and provided on the protective layer 46. That is, the lens unit 50 is indirectly provided on the second surface 21b of the substrate 21 via the second antireflection layer 41 and the protective layer 46. The lens unit 50 may be provided directly on the second surface 21b of the substrate 21 without the second antireflection layer 41 and the protective layer 46.

[0063] The lens portion 50 is configured as a Fresnel lens. As an example, the diameter of the lens portion 50 is about 750 μm. The number of circles in the Fresnel lens is 10 to 50, the height of the unevenness is 5 to 40 μm, and the distance between the circles is 5 to 50 μm. Such a lens portion 50 is formed by a method of patterning a resist (resin) using a 3D mask, a method using a mold, or the like.

[0064] 11, the lens portion 50 may be configured as a convex lens having a light exit surface 50a convex on the light exit side. As an example, the diameter of the lens portion 50 is about 750 μm. The height of the light exit surface 50a convex on the light exit side is 100 to 400 μm. Such a lens portion 50 is formed by a method of patterning a resist (resin) using a 3D mask, a method of patterning a resist (resin) using a normal mask and curing it, a method of using a mold, or the like.

[0065] 12 and 13, a lens portion 50 configured separately from the substrate 21 may be fixed in the opening 40a, for example, by an adhesive. In this case, the lens portion 50 may be indirectly provided on the second surface 21b of the substrate 21 via the second antireflection layer 41 and the protective layer 46, or may be directly provided on the second surface 21b of the substrate 21 without the second antireflection layer 41 and the protective layer 46.

[0066] 12, when lens portion 50 is configured as a Fresnel lens, as an example, the diameter of lens portion 50 is about 750 μm, the thickness of the substrate of lens portion 50 is 200 μm, and when lens portion 50 is made of silicon, the refractive index of lens portion 50 is 3.5. Also, the number of circles in the Fresnel lens is 5 or more, the height of the unevenness is 30 μm or less, and the distance between the circles is 80 μm or less.

[0067] 13, when the lens portion 50 is configured as a convex lens, for example, the diameter of the lens portion 50 is about 750 μm, and when the lens portion 50 is made of silicon, the refractive index of the lens portion 50 is 3.5. Also, the height of the light exit surface 50a convex on the light exit side is 50 to 400 μm.

[0068] In the photodetector 1C configured as above, the lens portion 50 is integrally provided on the second surface 21b side of the substrate 21, so that highly sensitive and highly accurate detection is possible, similar to the above-mentioned photodetector 1A.

[0069] Moreover, in the light detecting device 1C, the lens portion 50 is provided directly or indirectly on the second surface 21b of the substrate 21. This configuration can improve the stress balance of the Fabry-Perot interference filter 10C compared to the case where the lens portion 50 is formed in a part of the substrate 21. Also, the degree of freedom of the shape that the lens portion 50 can take (such as the curvature of the lens surface of the light exit surface 50a) can be increased.

[0070] In the light detection device 1C, the lens unit 50 is disposed within the opening 40a. With this configuration, even if the lens unit 50 is separate from the substrate 21, it is possible to prevent the position of the lens unit 50 from being shifted. In addition, while preventing the thickness of the Fabry-Perot interference filter 10C from increasing, for example, by increasing the thickness of the lens unit 50 by the amount of the lens unit 50 disposed within the opening 40a, it is possible to improve the light collecting function of the lens unit 50. Furthermore, by disposing the entire lens unit 50 within the opening 40a, it is possible to prevent the lens unit 50 from being damaged or contaminated.

[0071] Furthermore, when attaching the lens portion 50 to the second surface 21b of the substrate 21, the opening 40a can be used as an alignment reference so that the lens portion 50 fits into the opening 40a, so that the lens portion 50 can be mounted easily and with high precision.

[0072] Furthermore, in the case of manufacturing the Fabry-Perot interference filter 10C at the wafer level in a semiconductor manufacturing process, the lens portion 50 can also be implemented at the wafer level, making it possible to easily manufacture a Fabry-Perot interference filter 10C having a small lens portion 50 with high positional accuracy.

[0073] 14 and 15, the second layer structure 40 does not have to be configured on the second surface 21b of the substrate 21. In this case, the stress balance of the Fabry-Perot interference filter 10C can be improved compared to the case where the lens portion 50 is formed in a part of the substrate 21. In addition, the degree of freedom of the shape that the lens portion 50 can take (such as the curvature of the lens surface of the light exit surface 50a) can be increased.

[0074] 14, when the lens portion 50 is configured as a convex lens, for example, the diameter of the lens portion 50 is about 1000 μm, and when the lens portion 50 is made of silicon, the refractive index of the lens portion 50 is 3.5. The height of the light exit surface 50a convex on the light exit side is 50 to 400 μm. A light-shielding layer 45 may be formed on the second surface 21b side of the substrate 21 so as to surround the lens portion 50.

[0075] 15, when the lens portion 50 is configured as a Fresnel lens, for example, the diameter of the lens portion 50 is about 1000 μm, the thickness of the substrate of the lens portion 50 is 200 μm, and when the lens portion 50 is made of silicon, the refractive index of the lens portion 50 is 3.5. The number of circles of the Fresnel lens is 10 or more, the height of the unevenness is 40 μm or less, and the distance between the circles is 50 μm or less. A light-shielding layer 45 may be formed on the second surface 21b side of the substrate 21 so as to surround the lens portion 50. [Variations]

[0076] Although the first, second and third embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments. For example, the materials and shapes of each component are not limited to those described above, and various materials and shapes can be adopted.

[0077] Moreover, the lens portion 50 may be provided integrally on the second surface 21b side of the substrate 21. In other words, the lens portion 50 may be provided behind the first mirror portion 35 and the second mirror portion 36 as a part of each of the Fabry-Perot interference filters 10A, 10B, and 10C at the time of manufacturing each of the Fabry-Perot interference filters 10A, 10B, and 10C.

[0078] As long as the second layer structure 40 is configured to correspond to the first layer structure 30, it does not have to have a layered structure symmetrical to that of the first layer structure 30 with respect to the substrate 21. As long as the second layer structure 40 has a layered structure that can suppress warping, etc. of the substrate 21 compared to a case in which the second layer structure 40 is not provided, the second layer structure 40 can be said to be configured to correspond to the first layer structure 30.

[0079] The bandpass filter 14 may be provided on the light incident surface 13a of the light transmitting member 13, or on both the light incident surface 13a and the light exit surface 13b of the light transmitting member 13.

[0080] Furthermore, when viewed from a direction parallel to the line L, the outer edge of the light transmission region 10a of each of the Fabry-Perot interference filters 10A, 10B, and 10C may be located outside the outer edge of the window portion 15. In this case, the ratio of light entering the light transmission region 10a out of the light incident from the window portion 15 increases, and the utilization efficiency of the light incident from the window portion 15 increases. Furthermore, even if the position of the window portion 15 with respect to the light transmission region 10a is slightly shifted, the light incident from the window portion 15 enters the light transmission region 10a, so the requirement for positional accuracy during assembly of the photodetectors 1A, 1B, and 1C is relaxed. [Reference example]

[0081] 16, the Fabry-Perot interference filter 100 includes a first substrate 101, a second substrate 102, a first mirror portion 103, a second mirror portion 104, a first electrode 105, a second electrode 106, and a lens portion 107. In the Fabry-Perot interference filter 100, for example, a light transmission region 110a is set with a line L as a center line.

[0082] The first substrate 101 and the second substrate 102 are overlapped with each other in a direction parallel to the line L. The surface 101a of the first substrate 101 is bonded to the surface 102a of the second substrate 102. The first mirror portion 103 is provided in a portion of the first substrate 101 corresponding to the light transmitting region 110a. The second mirror portion 104 is provided in a portion of the second substrate 102 corresponding to the light transmitting region 110a. The first mirror portion 103 and the second mirror portion 104 face each other in a direction parallel to the line L with a gap S interposed therebetween. The first electrode 105 is provided on the first substrate 101 so as to surround the first mirror portion 103 when viewed from a direction parallel to the line L. The second electrode 106 is provided on the second substrate 102 so as to surround the second mirror portion 104 when viewed from a direction parallel to the line L. The first electrode 105 and the second electrode 106 face each other in a direction parallel to the line L with a gap S therebetween.

[0083] A groove 102c is formed on the surface 102b of the second substrate 102 opposite to the first substrate 101 so as to surround the second mirror portion 104 and the second electrode 106 when viewed from a direction parallel to the line L. The portion of the second substrate 102 surrounded by the groove 102c can be displaced in a direction parallel to the line L with the portion where the groove 102c is formed being a diaphragm-shaped holding portion 102d. The diaphragm-shaped holding portion 102d may be configured by forming a groove on the surface 102a of the second substrate 102 so as to surround the second mirror portion 104 and the second electrode 106 when viewed from a direction parallel to the line L. In addition, a groove may be formed on the surface 101b of the first substrate 101 opposite to the second substrate 102 or on the surface 101a of the first substrate 101 so as to surround the first mirror portion 103 and the first electrode 105 when viewed from a direction parallel to the line L, thereby configuring a diaphragm-shaped holding portion. In this case, the portion of first substrate 101 surrounded by the groove can be displaced in a direction parallel to line L, with the portion in which the groove is formed serving as a diaphragm-shaped retaining portion. Also, instead of the diaphragm-shaped retaining portion, the retaining portion may be formed of a plurality of beams arranged radially with line L as the center.

[0084] In the Fabry-Perot interference filter 100, when a voltage is applied between the first electrode 105 and the second electrode 106, an electrostatic force corresponding to the voltage is generated between the first electrode 105 and the second electrode 106. The electrostatic force attracts a portion of the second substrate 102 surrounded by the groove 102c toward the first substrate 101, and the distance between the first mirror portion 103 and the second mirror portion 104 is adjusted. Then, light having a wavelength corresponding to the distance between the first mirror portion 103 and the second mirror portion 104 is transmitted through the first mirror portion 103 and the second mirror portion 104 from the first substrate 101 side to the second substrate 102 side.

[0085] The lens portion 107 is integrally provided on the surface 102b side of the second substrate 102. The lens portion 107 collects light transmitted through the first mirror portion 103 and the second mirror portion 104. The lens portion 107 is provided directly or indirectly on the surface 102b as a Fresnel lens. The lens portion 107 may be provided directly or indirectly on the surface 102b as a convex lens. The lens portion 107 may be formed as a Fresnel lens or a convex lens on a portion of the second substrate 102 on the surface 102b side.

[0086] As an example, light transmitted through the first mirror portion 103 and the second mirror portion 104 is focused by the lens portion 107 on a photodetector (a photodetector disposed away from the Fabry-Perot interference filter 100) disposed inside or outside a package accommodating the Fabry-Perot interference filter 100. According to the Fabry-Perot interference filter 100 configured as described above, the lens portion 107 is integrally provided on the surface 102b side of the second substrate 102, enabling highly sensitive and highly accurate detection in the photodetector at the subsequent stage.

[0087] The specific configuration of the Fabry-Perot interference filter 100 will be described below. The first substrate 101 and the second substrate 102 are each formed into a rectangular plate shape from various glasses such as soda glass, crystalline glass, quartz glass, lead glass, potassium glass, borosilicate glass, or alkali-free glass, or from quartz. The thickness of the first substrate 101 is, for example, about 500 μm. The thickness of the second substrate 102 is, for example, about 200 μm. The surface 101a of the first substrate 101 and the surface 102a of the second substrate 102 are bonded to each other by, for example, a plasma polymerization film or the like.

[0088] The first substrate 101 has a surface 101c and a surface 101d that face the surface 102a of the second substrate 102 through a gap S in a direction parallel to the line L. The surface 101c is formed in a circular shape with the line L as a center line. The surface 101d is formed in an annular shape with the line L as a center line so as to surround the surface 101c when viewed from a direction parallel to the line L. The distance between the surface 101c of the first substrate 101 and the surface 102a of the second substrate 102 is smaller than the distance between the surface 101d of the first substrate 101 and the surface 102a of the second substrate 102. The groove 102c for forming a diaphragm in the second substrate 102 is formed in an annular shape with the line L as a center line. The surface 101c and the surface 101d of the first substrate 101 are formed by etching the first substrate 101 from the surface 101a side. The grooves 102c of the second substrate 102 are formed by etching the second substrate 102 from the surface 102b side.

[0089] The first mirror portion 103 is formed on a surface 101c of the first substrate 101. The second mirror portion 104 is formed on a surface 102a of the second substrate 102. The first mirror portion 103 and the second mirror portion 104 are, for example, a metal film, a dielectric multilayer film, or a composite film thereof, and each is formed in the shape of a circular film with the line L as the center line.

[0090] The first electrode 105 is formed on the surface 101d of the first substrate 101. The second electrode 106 is formed on the surface 102a of the second substrate 102. The first electrode 105 and the second electrode 106 are formed of, for example, a metal material, and each extends in a circular shape with the line L as a center line. The first electrode 105 is electrically connected to, for example, an electrode pad (not shown) provided in an area of ​​the first substrate 101 that is accessible from the outside via a wiring (not shown). The wiring is provided, for example, in a groove formed in the surface 101a of the first substrate 101. The second electrode 106 is electrically connected to, for example, an electrode pad (not shown) provided in an area of ​​the second substrate 102 that is accessible from the outside via a wiring (not shown). The wiring is provided, for example, in a groove formed in the surface 102a of the second substrate 102.

[0091] The lens portion 107 is formed of, for example, silicon, resin, glass, etc. The lens portion 107 is bonded to an area inside the groove 102c of the surface 102a of the second substrate 102 by, for example, an optical resin. When viewed from a direction parallel to the line L, the outer edge of the lens portion 107 includes the outer edge of the first mirror portion 103 and the outer edge of the second mirror portion 104.

[0092] A light-shielding layer 108 having an opening 108a is formed on the surface 101b of the first substrate 101. The light-shielding layer 108 is formed of, for example, a metal material. The opening 108a is formed in a circular shape with the line L as the center line, and functions as an aperture that narrows down the light incident on the light-transmitting region 110a. An anti-reflection layer may be formed on at least a region of the surface 101b of the first substrate 101 facing the first mirror portion 103 (i.e., at least a region inside the opening 108a) and at least a region of the surface 102b of the second substrate 102 facing the second mirror portion 104 (i.e., at least a region facing the lens portion 107). [Explanation of symbols]

[0093] Reference Signs List 1A, 1B, 1C...photodetector, 2...package, 8...photodetector, 8a...light-receiving area, 9...spacer (support portion), 10A, 10B, 10C...Fabry-Perot interference filter, 15...window portion, 21...substrate, 21a...first surface, 21b...second surface, 30...first layer structure, 35...first mirror portion, 36...second mirror portion, 40...second layer structure, 40a...opening, 50...lens portion, S...gap.

Claims

1. a package having a window for allowing light to enter; a bandpass filter disposed on an inner surface of the package for transmitting the light incident through the window; a Fabry-Perot interference filter disposed within the package and transmitting the light transmitted through the bandpass filter; When viewed from the incident direction of the light, an outer edge of the bandpass filter is located outside an outer edge of the Fabry-Perot interference filter, The Fabry-Perot interference filter comprises: a substrate having a first surface on the window side and a second surface opposite the window; a first layer structure including a first mirror portion and a second mirror portion disposed on the first surface, the first mirror portion facing each other with a gap therebetween and a distance between the first mirror portion and the second mirror portion being variable; a lens portion that is integrally provided on the second surface side and that collects the light that has passed through the first mirror portion and the second mirror portion, The first layer structure is a first stack disposed on the first surface and including the first mirror portion; an intermediate layer disposed on the first laminate and forming the gap; a second stack disposed on the intermediate layer and including the second mirror portion; The filter device, wherein the lens portion is located inside the gap when viewed from the incident direction of the light.

2. a package having a window for allowing light to enter; a bandpass filter disposed on an inner surface of the package for transmitting the light incident through the window; a Fabry-Perot interference filter disposed within the package and transmitting the light transmitted through the bandpass filter; When viewed from the incident direction of the light, an outer edge of the bandpass filter is located outside an outer edge of the Fabry-Perot interference filter, The Fabry-Perot interference filter comprises: a substrate having a first surface on the window side and a second surface opposite the window; a first layer structure including a first mirror portion and a second mirror portion disposed on the first surface, the first mirror portion facing each other with a gap therebetween and a distance between the first mirror portion and the second mirror portion being variable; a lens portion that is integrally provided on the second surface side and that collects the light that has passed through the first mirror portion and the second mirror portion; a first terminal and a second terminal provided on the first layer structure, The first layer structure is a first stack disposed on the first surface and including the first mirror portion; an intermediate layer disposed on the first laminate and forming the gap; a second stack disposed on the intermediate layer and including the second mirror portion; The filter device, wherein the first terminal and the second terminal are located outside the lens portion when viewed from a direction in which the light is incident.

3. The filter device according to claim 1 , wherein the lens portion is formed on a portion of the substrate on the second surface side.

4. The filter device according to claim 1 , wherein the lens portion is provided directly or indirectly on the second surface.

5. The Fabry-Perot interference filter comprises: a second layer structure disposed on the second surface and configured to correspond to the first layer structure; an opening is formed in the second layer structure through which the light transmitted through the first mirror portion and the second mirror portion passes; The filter device according to claim 4 , wherein the lens portion is disposed within the opening.

6. The Fabry-Perot interference filter comprises: a second layer structure disposed on the second surface and configured to correspond to the first layer structure; an opening is formed in the second layer structure through which the light transmitted through the first mirror portion and the second mirror portion passes; The filter device according to claim 1 , wherein the lens portion is attached to the second layer structure so as to cover the opening.

7. 7. The filter device according to claim 1, wherein an outer edge of the lens portion is located inside an outer edge of the window portion when viewed from the incident direction of the light.

8. a light transmitting member disposed between the inner surface of the package and the bandpass filter; 8. The filter device according to claim 1, wherein, when viewed from the direction in which the light is incident, the outer edge of the bandpass filter is located inside the outer edge of the light transmitting member.

9. 9. The filter device according to claim 8, wherein, when viewed from the direction of incidence of the light, an outer edge of the window portion is located inside the outer edge of the light transmitting member, the outer edge of the bandpass filter, and the outer edge of the Fabry-Perot interference filter.

10. The package includes a side wall and a top wall; An opening that functions as the window portion is formed in the top wall, the light transmitting member extends into the opening of the top wall and to an inner surface of the side wall, 10. The filter device according to claim 8, wherein the light incident surface of the light transmitting member is substantially flush with an outer surface of the top wall at the opening of the top wall.

Images