Optical element and optical device

Abstract

This optical element is provided with: a light-transmitting substrate having a first surface and a second surface; a light-blocking layer that is disposed on the first surface and has a light-passing aperture; a first multilayer film filter that is disposed on the first surface and covers a light-passing region of the first surface that overlaps the light-passing aperture when viewed from the thickness direction of the light-transmitting substrate, and a light-blocking region of the surface of the light-blocking layer, said light-blocking region surrounding the light-passing aperture when viewed from the thickness direction of the light-transmitting substrate; and a second multilayer film filter that is disposed on the second surface and overlaps the light-passing region and the light-blocking region when viewed from the thickness direction of the light-transmitting substrate.

Description

Optical elements and optical devices

[0001] The present disclosure relates to optical elements and optical devices.

[0002] An optical device is known that includes an optical element, a package having an opening in which the optical element is disposed, and a Fabry-Perot interference filter disposed within the package and including a pair of mirror portions whose distance from each other is variable, in which the optical element includes a light-transmitting substrate and a light-shielding layer formed on the outer surface of the light-transmitting substrate and having a light-passing opening (see, for example, Patent Document 1).

[0003] JP 2016-211860 A

[0004] In the optical device described above, when measuring light within a predetermined wavelength range, how to prevent light other than that wavelength range from entering the package is extremely important in improving the S / N ratio in wavelength analysis of the measurement target. In other words, how to reliably transmit light within the predetermined wavelength range through the optical element disposed in the opening of the package is extremely important.

[0005] Therefore, an object of the present disclosure is to provide an optical element that can reliably transmit light in a predetermined wavelength range, and an optical device that includes such an optical element.

[0006] An optical element according to one aspect of the present disclosure is [1] "an optical element comprising: a light-transmitting substrate having a first surface and a second surface opposite to the first surface; a light-shielding layer disposed on the first surface and having a light-passing opening; a first multilayer filter disposed on the first surface and covering a light-passing region of the first surface overlapping with the light-passing opening when viewed in the thickness direction of the light-transmitting substrate and a light-shielding region of a surface of the light-shielding layer opposite to the light-transmitting substrate that surrounds the light-passing opening when viewed in the thickness direction of the light-transmitting substrate; and a second multilayer filter disposed on the second surface overlapping with the light-passing region and the light-shielding region when viewed in the thickness direction of the light-transmitting substrate."

[0007] In the optical element, regardless of whether light is incident on the light-transmitting substrate from the first surface side or the second surface side, the light-passing opening of the light-shielding layer functions as an aperture, while the light-transmitting substrate, the first multilayer filter, and the second multilayer filter function as a bandpass filter. Furthermore, because the light-shielding layer and the first multilayer filter are disposed on the first surface and the second multilayer filter is disposed on the second surface, even if light enters the light-transmitting substrate from a side surface of the light-transmitting substrate, the light can be prevented from emitting directly to the outside. Furthermore, because the first multilayer filter is disposed on the first surface and the second multilayer filter is disposed on the second surface, warping of the light-transmitting substrate is less likely to occur, allowing the first multilayer filter and the second multilayer filter to function properly. Therefore, the optical element can reliably transmit light within a predetermined wavelength range.

[0008] The optical element according to one aspect of the present disclosure may be [2] "the optical element according to the above [1], in which the light-transmitting substrate is a silicon substrate." According to this optical element, the light-transmitting substrate, the first multilayer filter, and the second multilayer filter can function as a bandpass filter by utilizing the selectivity of transmission wavelengths that silicon itself has.

[0009] The optical element according to one aspect of the present disclosure may be [3] "the optical element according to the above [1] or [2], wherein, when viewed from the thickness direction of the light-transmitting substrate, an outer edge of the light-shielding layer is located inside the outer edge of the light-transmitting substrate, and when viewed from the thickness direction of the light-transmitting substrate, an outer edge of the first multilayer filter is located outside the outer edge of the light-shielding layer." With this optical element, the first multilayer filter can function as a protective layer, thereby suppressing deterioration of the light-shielding layer.

[0010] An optical element according to one aspect of the present disclosure may be [4] "the optical element according to the above [1] or [2], in which, when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the light-shielding layer reaches the outer edge of the light-transmitting substrate." According to this optical element, when light is incident on the light-transmitting substrate from the first surface side, it is possible to prevent the light from entering the light-transmitting substrate through the outer edge region of the first surface. Furthermore, when light is incident on the light-transmitting substrate from the second surface side, it is possible to prevent the light from exiting the light-transmitting substrate through the outer edge region of the first surface.

[0011] The optical element according to one aspect of the present disclosure may be [5] "the optical element according to any one of [1] to [4] above, wherein, when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the second multilayer filter is located outside the outer edge of the light-shielding layer." According to this optical element, regardless of whether light is incident on the light-transmitting substrate from the first surface side or the second surface side, the light can be reliably transmitted through the second multilayer filter.

[0012] An optical device according to one aspect of the present disclosure is [6] "an optical device comprising: an optical element according to any one of [1] to [5] above; a package having an opening in which the optical element is disposed; and a Fabry-Perot interference filter disposed within the package and including a pair of mirror portions whose distance from each other is variable; wherein, when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the light-passing opening is located inside the outer edge of the Fabry-Perot interference filter."

[0013] In the optical device, as described above, the light passing opening of the light-shielding layer in the optical element can function as an aperture, while the light-transmitting substrate, the first multilayer filter, and the second multilayer filter can function as a band-pass filter. Therefore, with the optical device, when light in a predetermined wavelength range is to be incident on the Fabry-Perot interference filter, it is possible to prevent light other than light in the predetermined wavelength range from entering the package.

[0014] The optical device according to one aspect of the present disclosure may be [7] "the optical device according to the above [6], in which, when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the light-shielding layer is located outside the outer edge of the opening defined by the opening." With this optical device, it is possible to prevent light from entering the package from any point other than the light passage opening of the optical element.

[0015] The optical device according to one aspect of the present disclosure may be [8] "the optical device according to the above [6] or [7], in which, when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the first multilayer filter or the outer edge of the second multilayer filter is located outside the outer edge of the opening defined by the opening." With this optical device, even if light is incident on the light-transmitting substrate from a side surface of the light-transmitting substrate, the light can be prevented from directly entering the package.

[0016] The optical device according to one aspect of the present disclosure may be [9] "the optical device according to any one of the above [6] to [8], wherein the optical element is disposed in the opening with the second surface positioned on the Fabry-Perot interference filter side relative to the first surface." With this optical device, the distance between the light passing opening of the light-shielding layer and the Fabry-Perot interference filter is increased, thereby limiting the angle of incidence of light incident on the Fabry-Perot interference filter.

[0017] The optical device according to one aspect of the present disclosure may be

[10] "the optical device according to the above [9], further comprising a light-absorbing adhesive member, the optical element being disposed on a mounting surface of the package, the adhesive member being in contact with the mounting surface of the package and a side surface of the optical element, and extending up to the height of the light-shielding layer in the thickness direction of the light-transmitting substrate." This optical device can prevent light from entering the light-transmitting substrate from a side surface of the light-transmitting substrate.

[0018] The optical device according to one aspect of the present disclosure may be

[11] "the optical device according to any one of [6] to [8] above, wherein the optical element is disposed in the opening with the first surface positioned on the Fabry-Perot interference filter side relative to the second surface." According to this optical device, a light-shielding layer is disposed on the Fabry-Perot interference filter side of the light-transmitting substrate, so that even if light is incident on the light-transmitting substrate from a side surface of the light-transmitting substrate, the light can be prevented from directly entering the package.

[0019] According to the present disclosure, it is possible to provide an optical element that can reliably transmit light within a predetermined wavelength range, and an optical device that includes such an optical element.

[0020] FIG. 1 is a cross-sectional view of an optical device of one embodiment. FIG. 2 is a plan view of the optical device shown in FIG. 1. FIG. 3 is a perspective view of the Fabry-Perot interference filter shown in FIG. 1. FIG. 4 is a cross-sectional view of the Fabry-Perot interference filter along line IV-IV shown in FIG. 3. FIG. 5 is a cross-sectional view of the optical element shown in FIG. 1. FIG. 6 is a plan view of the optical element shown in FIG. 1. FIG. 7 is a schematic diagram showing optical characteristics of the optical element shown in FIG. 1. FIG. 8 is a cross-sectional view of an optical element of a modified example. FIG. 9 is a cross-sectional view of an optical element of a modified example. FIG. 10 is a cross-sectional view of an optical element of a modified example. FIG. 11 is a cross-sectional view of an optical device of a modified example.

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted. [Configuration of Optical Device]

[0022] As shown in FIGS. 1 and 2 , the optical device 1 includes a Fabry-Perot interference filter 2, a photodetector 3, a temperature compensation element 4, a package 5, and an optical element 10. The Fabry-Perot interference filter 2, the photodetector 3, and the temperature compensation element 4 are disposed within the package 5. The optical element 10 is disposed in an opening 5a of the package 5. The optical element 10, the Fabry-Perot interference filter 2, and the photodetector 3 are aligned on a straight line L. Hereinafter, a direction parallel to the straight line L will be referred to as the Z-axis direction, a direction perpendicular to the Z-axis direction will be referred to as the X-axis direction, and a direction perpendicular to the Z-axis and X-axis directions will be referred to as the Y-axis direction. Note that FIG. 1 shows a cross-sectional structure of the optical device 1 taken along a dashed line shown in FIG. 2 . Furthermore, in FIG. 2 , the optical element 10 is omitted, and the Fabry-Perot interference filter 2 is indicated by a dashed double-dashed line.

[0023] The package 5 is configured as an SMD (Surface Mount Device) package by stacking a first layer 51, a second layer 53, a third layer 54, and a fourth layer 55 in this order. The first layer 51 is formed into a rectangular plate shape from, for example, ceramic or resin. The second layer 53, the third layer 54, and the fourth layer 55 are each formed into a rectangular frame shape from, for example, ceramic or resin. In the optical device 1, the fourth layer 55 forms the opening 5a.

[0024] When viewed from the Z-axis direction, the opening 53a of the second layer 53 has a shape that extends from the central region of the first layer 51 to one side in the X-axis direction (the left side in FIGS. 1 and 2 ). When viewed from the Z-axis direction, the opening 54a of the third layer 54 has a shape that is wider than the opening 53a of the second layer 53 to the other side in the X-axis direction (the right side in FIGS. 1 and 2 ) and on both sides in the Y-axis direction. When viewed from the Z-axis direction, the opening 55a of the fourth layer 55 has a shape that is wider than the opening 54a of the third layer 54 to both sides in the X-axis direction and on both sides in the Y-axis direction.

[0025] A plurality of electrode pads 61, 62 are formed on a region 51a of the surface of the first layer 51 facing the second layer 53, the region 51a being exposed through the opening 53a of the second layer 53. The electrode pad 61 is located on a straight line L. The photodetector element 3 is mounted on the electrode pad 61 so that the light-receiving region 3a is located on the straight line L. One electrode terminal of the photodetector element 3 is electrically connected to the electrode pad 61. The other electrode terminal of the photodetector element 3 is electrically connected to the electrode pad 62 via a wire 65a. The photodetector element 3 and the wire 65a are located within a space defined by the opening 53a of the second layer 53.

[0026] The photodetector element 3 is, for example, an infrared detector. Examples of the infrared detector include quantum sensors using InGaAs or the like, and thermal sensors using thermopiles or bolometers. Depending on the detection wavelength, the photodetector element 3 may be, for example, a silicon photodiode. The light-receiving region 3 a of the photodetector element 3 may be composed of a single light-receiving unit, or may be composed of multiple light-receiving units arranged in an array. The multiple light-receiving units may be composed of a single chip, or may be composed of multiple chips.

[0027] A plurality of electrode pads 63, 64 are further formed in the region 51a of the first layer 51. The electrode pad 63 is located on one side of the electrode pad 61 in the X-axis direction. A temperature compensation element 4 is mounted on the electrode pad 63. One polarity terminal of the temperature compensation element 4 is electrically connected to the electrode pad 63. The other polarity terminal of the temperature compensation element 4 is electrically connected to the electrode pad 64 via a wire 65b. The temperature compensation element 4 and the wire 65b are located within the space defined by the opening 53a of the second layer 53. The temperature compensation element 4 is, for example, a thermistor.

[0028] A plurality of electrode pads 66, 67 are formed in a region 54b of the surface of the third layer 54 facing the fourth layer 55, the region 54b being exposed through the opening 55a of the fourth layer 55. A Fabry-Perot interference filter 2 is disposed in a region 53b of the surface of the second layer 53 facing the third layer 54, the region 53b being exposed through the opening 54a of the third layer 54, such that the light-transmitting region 2a is positioned on the straight line L. In the optical device 1, a portion of the Fabry-Perot interference filter 2 that surrounds the light-transmitting region 2a in a U-shape when viewed from the Z-axis direction is fixed to the U-shaped region 53b with an adhesive member (not shown). One polarity side terminal of the Fabry-Perot interference filter 2 is electrically connected to an electrode pad 66 via a wire 65c. The other polarity side terminal of the Fabry-Perot interference filter 2 is electrically connected to an electrode pad 67 via a wire 65d. The Fabry-Perot interference filter 2 and the plurality of wires 65c, 65d are located within a space defined by the opening 54a in the third layer 54 and the opening 55a in the fourth layer 55. The Fabry-Perot interference filter 2 is a filter element including a pair of a first mirror portion (mirror portion) 35 and a second mirror portion (mirror portion) 36, the distance between which is variable (see FIG. 4).

[0029] A plurality of electrode pads 68 for mounting the optical device 1 on an external wiring board are formed on a surface 51b of the first layer 51 opposite to the second layer 53. Each of the electrode pads 61, 62, 63, and 64 is electrically connected to the corresponding electrode pad 68 via wiring (not shown) formed within each of the first layer 51, the second layer 53, the third layer 54, and the fourth layer 55 and / or between adjacent layers. The wiring is drawn out in the Z-axis direction via the outer side surfaces of each of the first layer 51, the second layer 53, the third layer 54, and the fourth layer 55 and / or through holes formed in those layers.

[0030] The optical element 10 is disposed on a surface 55b of the fourth layer 55 opposite to the third layer 54. In the optical device 1, the outer edge portion of the optical element 10 is fixed to the surface 55b by a light-absorbing adhesive member 7. The optical element 10 is a filter element that transmits light within a predetermined wavelength range from outside the package 5 to inside the package 5.

[0031] In the optical device 1 configured as described above, when light in a predetermined wavelength range enters the package 5 via the optical element 10 and enters the light-transmitting region 2a of the Fabry-Perot interference filter 2, light having a wavelength corresponding to the distance between the first mirror portion 35 and the second mirror portion 36 of the light passes through the light-transmitting region 2a of the Fabry-Perot interference filter 2. The light that has passed through the light-transmitting region 2a of the Fabry-Perot interference filter 2 enters the light-receiving region 3a of the photodetector 3 and is detected by the photodetector 3. As an example, in order to obtain a spectrum of light in a predetermined wavelength range, in the optical device 1, the voltage applied to the Fabry-Perot interference filter 2 is changed (i.e., the distance between the first mirror portion 35 and the second mirror portion 36 of the Fabry-Perot interference filter 2 is changed), and the light that has passed through the light-transmitting region 2a of the Fabry-Perot interference filter 2 is detected by the photodetector 3. [Configuration of the Fabry-Perot Interference Filter]

[0032] As shown in Fig. 3, the Fabry-Perot interference filter 2 has a light-transmitting region 2a. The light-transmitting region 2a is located on a straight line L. As an example, the Fabry-Perot interference filter 2 has a rectangular plate shape, and the light-transmitting region 2a has a cylindrical shape with the straight line L as its center line. As shown in Fig. 4, the Fabry-Perot interference filter 2 includes a pair of first and second mirror portions 35 and 36. The distance between the pair of first and second mirror portions 35 and 36 is variable in direction A (a direction parallel to the Z-axis direction). The first and second mirror portions 35 and 36 face each other in direction A.

[0033] The Fabry-Perot interference filter 2 includes a substrate 21. An antireflection layer 31, a first stacked body 32, an intermediate layer 33, and a second stacked body 34 are stacked in this order on a light-incident surface 21a of the substrate 21. An air gap S is formed between the first stacked body 32 and the second stacked body 34 by a frame-shaped intermediate layer 33. The substrate 21 is made of a material such as silicon, quartz, glass, etc. When the substrate 21 is made of silicon, the antireflection layer 31 and the intermediate layer 33 are made of a material such as silicon oxide, etc. The thickness of the intermediate layer 33 is, for example, an integral multiple of ½ the design center wavelength. Note that the thickness of the intermediate layer 33 may be greater than an integral multiple of ½ the design center wavelength, if necessary.

[0034] The portion of the first stack 32 corresponding to the light-transmitting region 2a functions as a first mirror section 35. The first mirror section 35 is supported on the substrate 21 via an anti-reflection layer 31. As an example, the first stack 32 is configured by alternately stacking a plurality of polysilicon layers and a plurality of silicon nitride layers. The optical thickness of each layer constituting the first mirror section 35 is, for example, an integral multiple of ¼ of the design central wavelength. Note that a silicon oxide layer may be used instead of the silicon nitride layer.

[0035] The portion of the second stack 34 corresponding to the light-transmitting region 2a functions as a second mirror section 36 facing the first mirror section 35 across a gap S. The second mirror section 36 is supported on the substrate 21 via an anti-reflection layer 31, the first stack 32, and an intermediate layer 33. As an example, the second stack 34 is configured by alternately stacking multiple polysilicon layers and multiple silicon nitride layers. The optical thickness of each layer constituting the second mirror section 36 is, for example, an integral multiple of ¼ of the design central wavelength. Note that a silicon oxide layer may be used instead of the silicon nitride layer.

[0036] A plurality of through holes 34b are formed in the portion of the second laminate 34 corresponding to the void S, so as to extend from the surface 34a of the second laminate 34 opposite the void S 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 when forming the void S by removing a portion of the intermediate layer 33 by etching.

[0037] A first electrode 22 is formed on the first mirror portion 35 so as to surround the light-transmitting region 2a. A second electrode 23 is formed on the first mirror portion 35 so as to include the light-transmitting region 2a. Each of the first electrode 22 and the second electrode 23 is formed by doping impurities into a portion of the polysilicon layer to reduce the resistance of that portion. The size of the second electrode 23 is approximately the same as the size of the light-transmitting region 2a.

[0038] A third electrode 24 is formed on the second mirror portion 36. The third electrode 24 faces the first electrode 22 and the second electrode 23 in direction A across a gap S. The third electrode 24 is formed by doping an impurity into a portion of the polysilicon layer to reduce the resistance of that portion.

[0039] In the Fabry-Perot interference filter 2, the second electrode 23 is located on the same plane as the first electrode 22 in a direction perpendicular to direction A. The distance between the second electrode 23 and the third electrode 24 is approximately the same as the distance between the first electrode 22 and the third electrode 24. When viewed from direction A, the second electrode 23 is surrounded by the first electrode 22.

[0040] The Fabry-Perot interference filter 2 is provided with a pair of terminals 25 on either side of the light transmission region 2a. Each terminal 25 is disposed in a through hole extending from the surface 34a of the second laminate 34 to the first laminate 32. Each terminal 25 is electrically connected to the first electrode 22 via a wiring 22a.

[0041] The Fabry-Perot interference filter 2 is provided with a pair of terminals 26 on either side of the light-transmitting region 2a. Each terminal 26 is disposed in a through-hole extending from the surface 34a of the second laminate 34 to the intermediate layer 33. Each terminal 26 is electrically connected to the second electrode 23 via a wiring 23a, and is also electrically connected to the third electrode 24 via a wiring 24a. The direction in which the pair of terminals 26 are arranged side by side across the light-transmitting region 2a is perpendicular to the direction in which the pair of terminals 25 are arranged side by side across the light-transmitting region 2a (see FIG. 3 ).

[0042] A pair of trenches 27 are formed in the first stack 32. Each trench 27 extends in an annular shape so as to surround a portion of the wiring 23a extending from each terminal 26 in the direction A. Each trench 27 electrically insulates the first electrode 22 from the wiring 23a. A trench 28 is formed in the first stack 32. The trench 28 extends in an annular shape along the inner edge of the first electrode 22. The trench 28 electrically insulates the first electrode 22 from the second electrode 23. The region within each trench 27, 28 may be filled with an insulating material or may be an empty space.

[0043] A pair of trenches 29 are formed in the second stack 34. Each trench 29 extends annularly so as to surround each terminal 25. Each trench 29 electrically insulates each terminal 25 from the third electrode 24. The area within each trench 29 may be filled with an insulating material or may be an empty space.

[0044] An antireflection layer 41, a third stacked body 42, an intermediate layer 43, and a fourth stacked body 44 are stacked in this order on the light-emitting surface 21b of the substrate 21. The antireflection layer 41 and the intermediate layer 43 have the same configurations as the antireflection layer 31 and the intermediate layer 33, respectively. The third stacked body 42 and the fourth stacked body 44 have stacked structures symmetrical to the first stacked body 32 and the second stacked body 34, respectively, with respect to the substrate 21. The antireflection layer 41, the third stacked body 42, the intermediate layer 43, and the fourth stacked body 44 have the function of suppressing warping of the substrate 21.

[0045] An opening 40a is formed in the third stack 42, the intermediate layer 43, and the fourth stack 44 so as to include the light-transmitting region 2a. When viewed from direction A, the size of the opening 40a is approximately the same as the size of the light-transmitting region 2a. The opening 40a is open to the light-emitting side, and the bottom surface of the opening 40a reaches the anti-reflection layer 41. 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. Note that by setting the thickness of the protective layer 46 to 100 nm or less (preferably, approximately 30 nm), the optical influence of the protective layer 46 can be ignored.

[0046] In the Fabry-Perot interference filter 2 configured as described above, when a voltage is applied to the first electrode 22 and the third electrode 24 via the multiple terminals 25, 26, generating a potential difference between the first electrode 22 and the third electrode 24, an electrostatic force corresponding to the potential difference is generated between the first electrode 22 and the third electrode 24. The electrostatic force generated between the first electrode 22 and the third electrode 24 attracts the second mirror portion 36 to the first mirror portion 35, thereby adjusting the distance between the first mirror portion 35 and the second mirror portion 36. At this time, the second electrode 23, which has the same potential as the third electrode 24, functions as a compensation electrode, keeping the second mirror portion 36 flat in the light transmission region 2a. In this way, in the Fabry-Perot interference filter 2, the distance between the pair of first mirror portion 35 and second mirror portion 36 (i.e., the distance between the first mirror portion 35 and the second mirror portion 36) is variable. Here, the wavelength of light transmitted through the Fabry-Perot interference filter 2 depends on the distance between the first mirror portion 35 and the second mirror portion 36. Therefore, by adjusting the voltage applied to the first electrode 22 and the third electrode 24 (the potential difference generated between the first electrode 22 and the third electrode 24), it is possible to select the wavelength of light transmitted through the Fabry-Perot interference filter 2. [Configuration of Optical Element]

[0047] As shown in FIGS. 5 and 6 , the optical element 10 includes a light-transmitting substrate 11, a light-shielding layer 12, a first multilayer filter 13, and a second multilayer filter 14. The light-transmitting substrate 11 has a first surface 11a and a second surface 11b opposite the first surface 11a. The light-transmitting substrate 11 is a silicon substrate whose thickness direction (i.e., the direction in which the first surface 11a and the second surface 11b face each other) is in the Z-axis direction. The light-transmitting substrate 11 is formed, for example, in the shape of a rectangular plate with a straight line L as its center line. As an example, the length of one side of the light-transmitting substrate 11 is approximately 2 to 20 mm, and the thickness of the light-transmitting substrate 11 is approximately 0.1 to 2 mm. In the optical device 1, the optical element 10 is disposed in the opening 5a of the package 5 with the second surface 11b positioned closer to the Fabry-Perot interference filter 2 than the first surface 11a.

[0048] The light-shielding layer 12 is disposed on the first surface 11a. The light-shielding layer 12 is formed in the shape of a rectangular film from a metal such as aluminum. As an example, the thickness of the light-shielding layer 12 is approximately 0.05 to 2 μm. A surface 12a of the light-shielding layer 12 opposite the light-transmitting substrate 11 is optically reflective to visible light. The light-shielding layer 12 has a light-passing opening 120. The light-passing opening 120 is located on a straight line L. When viewed from the Z-axis direction, the light-passing opening 120 has, for example, a circular shape centered on the straight line L. As an example, the diameter of the light-passing opening 120 is approximately 0.1 to 2 mm. When viewed from the Z-axis direction, an outer edge 12E of the light-shielding layer 12 is located inside the outer edge 11E of the light-transmitting substrate 11 and outside the outer edge 55E of the opening 55a of the package 5 (the opening defined by the opening 5a). When viewed from the Z-axis direction, the outer edge 120E of the light passing opening 120 is located inside the outer edge 2E of the Fabry-Perot interference filter 2.

[0049] The first multilayer filter 13 is disposed on the first surface 11a. The first multilayer filter 13 is formed, for example, in the shape of a rectangular film made of a plurality of types of dielectric material. In the optical device 1, the first multilayer filter 13 is a dielectric multilayer film (for example, TiO ２ , Ta ２ O ５ High refractive index materials such as SiO ２, MgF ２ The first multilayer filter 13 is a multilayer film formed by combining a low-refractive index material such as a fluorine-containing compound (e.g., a fluorine-containing compound) with a low-refractive index material such as a fluorine-containing compound (e.g., a fluorine-containing compound). As an example, the thickness of the first multilayer filter 13 is approximately 1 to 30 μm. When viewed from the Z-axis direction, the outer edge 13E of the first multilayer filter 13 is located outside the outer edge 12E of the light-shielding layer 12 and extends to the outer edge 11E of the light-transmitting substrate 11. The first multilayer filter 13 covers the entire surface 12a of the light-shielding layer 12. In other words, the first multilayer filter 13 covers at least "a light-passing region 11R of the first surface 11a of the light-transmitting substrate 11 that overlaps with the light-passing opening 120 when viewed from the Z-axis direction" and "a light-shielding region 12R of the surface 12a of the light-shielding layer 12 that surrounds the light-passing opening 120 when viewed from the Z-axis direction."

[0050] The second multilayer filter 14 is disposed on the second surface 11b. The second multilayer filter 14 is formed, for example, in the shape of a rectangular film made of a plurality of types of dielectric material. In the optical device 1, the second multilayer filter 14 is a dielectric multilayer film (for example, TiO ２ , Ta ２ O ５ High refractive index materials such as SiO ２ , MgF ２ The second multilayer filter 14 is a multilayer film formed by combining a low refractive index material such as a fluorine-containing compound (e.g., a fluorine-containing compound) with a low refractive index material such as a fluorine-containing compound (e.g., a fluorine-containing compound). As an example, the thickness of the second multilayer filter 14 is approximately 1 to 20 μm. When viewed from the Z-axis direction, the outer edge 14E of the second multilayer filter 14 is located outside the outer edge 12E of the light-shielding layer 12 and extends to the outer edge 11E of the light-transmitting substrate 11. The second multilayer filter 14 covers the entire second surface 11b of the light-transmitting substrate 11. In other words, when viewed from the Z-axis direction, the second multilayer filter 14 overlaps with the light-passing region 11R and the light-shielding region 12R.

[0051] An inscription 8 indicating predetermined information is applied to the "surrounding region 13R, which overlaps with the light-shielding region 12R when viewed from the Z-axis direction, of the surface 13a of the first multilayer filter 13 opposite the light-transmitting substrate 11." The surrounding region 13R is a region of the surface 13a of the first multilayer filter 13 that surrounds the light-passing opening 120 when viewed from the Z-axis direction. In the optical device 1, the inscription 8 is a character or code indicating, as the predetermined information, individual information of the Fabry-Perot interference filter 2. When viewed from the Z-axis direction, the shortest distance d1 between the inscription 8 and the outer edge 120E of the light-passing opening 120 is greater than the shortest distance d2 between the inscription 8 and the outer edge 12E of the light-shielding layer 12. A straight line α tangent to the inscription 8 and passing through the light-passing opening 120 does not intersect with the light-transmitting region 2a of the Fabry-Perot interference filter 2. That is, the straight line α deviates from the light-transmitting region 2a of the Fabry-Perot interference filter 2. The marking 8 is formed by engraving or pressing the surface of the object. In the optical device 1, the marking 8 is formed by irradiating the surrounding region 13R with a laser beam (by so-called laser marking technology).

[0052] The optical element 10 configured as described above is disposed on the surface (mounting surface) 55b of the fourth layer 55, with the outer edge 14E of the second multilayer filter 14 positioned outside the outer edge 55E of the opening 55a when viewed from the Z-axis direction. Specifically, the outer edge portion of the second multilayer filter 14 is positioned on the surface 55b in the Z-axis direction, and the outer edge portion of the optical element 10 is fixed to the surface 55b by the adhesive member 7. The adhesive member 7 is disposed from the region between the surface 55b of the package 5 and the outer edge portion of the second multilayer filter 14 to the region (corner) between the surface 55b of the package 5 and the side surface 10a of the optical element 10. The adhesive member 7 is in contact with the surface 55b of the package 5 and the side surface 10a of the optical element 10, extending to the height of the light-shielding layer 12 in the Z-axis direction. In the optical device 1, the adhesive member 7 is in contact with the side surface 11c of the light-transmitting substrate 11 on the side surface 10a of the optical element 10, and extends to the outer edge 13E of the first multilayer filter 13. Note that "the adhesive member 7 reaches the height of the light-shielding layer 12 in the Z-axis direction" means that the adhesive member 7 needs to reach at least the height of the surface of the light-shielding layer 12 facing the light-transmitting substrate 11. Therefore, the adhesive member 7 does not need to reach the height of the surface of the light-shielding layer 12 opposite the light-transmitting substrate 11, and in that case, the adhesive member 7 does not need to reach the outer edge 13E of the first multilayer filter 13.

[0053] In the optical element 10, as shown in FIG. 7 , the first multilayer filter 13 is a short-pass filter, and the second multilayer filter 14 is a long-pass filter. As an example, when the optical device 1 measures light in the near-infrared region, the first multilayer filter 13 selectively transmits light having a wavelength of 2000 nm or less, and the second multilayer filter 14 selectively transmits light having a wavelength of 1500 nm or more. This allows the optical element 10 to function as a band-pass filter that selectively transmits light having a wavelength of 1500 nm or more and 2000 nm or less. Here, because the first multilayer filter 13 is a short-pass filter that selectively transmits light having a wavelength of 2000 nm or less, visible light (light having a wavelength of 380 to 780 nm) incident on the first multilayer filter 13 from the outside passes through the first multilayer filter 13, is reflected by the surface 12 a of the light-shielding layer 12, and then passes through the first multilayer filter 13 to be emitted to the outside. On the other hand, the marking 8 has a rough surface, which easily scatters visible light. In this way, the light-shielding layer 12 has a high reflectance for visible light, while the marking 8 has a low reflectance for visible light, and the contrast between these two increases the visibility of the marking 8 in visible light.

[0054] In the optical element 10, the first multilayer filter 13 may be a long-pass filter, and the second multilayer filter 14 may be a short-pass filter. In this case, the first multilayer filter 13 has a high reflectance for visible light, while the inscription 8 has a low reflectance for visible light, and the contrast between the two increases the visibility of the inscription 8 in visible light. Alternatively, both the first multilayer filter 13 and the second multilayer filter 14 may be long-pass filters (either the same or different long-pass filters), or both the first multilayer filter 13 and the second multilayer filter 14 may be short-pass filters (either the same or different short-pass filters). In either case, the optical element 10 can function as a band-pass filter in cooperation with the selectivity of the transmission wavelengths possessed by the light-transmitting substrate 11. Furthermore, in either case, there are also advantages such as "the cooperation of the first multilayer filter 13 and the second multilayer filter 14 makes the rise of the change in transmittance on the short wavelength side or the fall of the change in transmittance on the long wavelength side sharper," "the first multilayer filter 13 and the second multilayer filter 14 easier to manufacture," and "the light-transmitting substrate 11 is less likely to warp." Note that when both the first multilayer filter 13 and the second multilayer filter 14 are long-pass filters, the optical element 10 can function in the same way as when a band-pass filter is used by using a photodetector element 3 that is not sensitive on the long wavelength side. Also, when both the first multilayer filter 13 and the second multilayer filter 14 are short-pass filters, the optical element 10 can function in the same way as when a band-pass filter is used by using a photodetector element 3 that is not sensitive on the short wavelength side. [Actions and Effects]

[0055] In the optical element 10, when light is incident on the light-transmitting substrate 11 from the first surface 11a side, the light passage opening 120 of the light-shielding layer 12 functions as an aperture, while the light-transmitting substrate 11, the first multilayer filter 13, and the second multilayer filter 14 function as bandpass filters. Furthermore, because the second multilayer filter 14 is disposed on the second surface 11b facing the Fabry-Perot interference filter 2, even if light enters the light-transmitting substrate 11 from the side surface 11c of the light-transmitting substrate 11, the light can be prevented from emitting directly into the package 5. Furthermore, because the first multilayer filter 13 is disposed on the first surface 11a and the second multilayer filter 14 is disposed on the second surface 11b, warping of the light-transmitting substrate 11 is less likely to occur, allowing the first multilayer filter 13 and the second multilayer filter 14 to function properly. Therefore, the optical element 10 can reliably transmit light within a predetermined wavelength range.

[0056] In the optical element 10, the light-transmitting substrate 11 is a silicon substrate, which allows the light-transmitting substrate 11, the first multilayer filter 13, and the second multilayer filter 14 to function as bandpass filters by utilizing the selectivity of transmission wavelengths that silicon itself possesses.

[0057] In the optical element 10, when viewed from the Z-axis direction, the outer edge 12E of the light-shielding layer 12 is located inside the outer edge 11E of the light-transmitting substrate 11, and the outer edge 13E of the first multilayer filter 13 is located outside the outer edge 12E of the light-shielding layer 12. This allows the first multilayer filter 13 to function as a protective layer, thereby suppressing deterioration of the light-shielding layer 12.

[0058] In the optical element 10, when viewed from the Z-axis direction, the outer edge 14E of the second multilayer filter 14 is located outside the outer edge 12E of the light-shielding layer 12. This allows light to reliably pass through the second multilayer filter 14 when it is incident on the light-transmitting substrate 11 from the first surface 11a side.

[0059] In the optical device 1, when viewed from the Z-axis direction, the outer edge 120E of the light passing opening 120 is located inside the outer edge 2E of the Fabry-Perot interference filter 2. This allows the light passing opening 120 of the light-shielding layer 12 to function as an aperture, while the light-transmitting substrate 11, the first multilayer filter 13, and the second multilayer filter 14 function as bandpass filters in the optical element 10. Therefore, according to the optical device 1, when light in a predetermined wavelength range is to be incident on the Fabry-Perot interference filter 2, it is possible to prevent light other than light in the predetermined wavelength range from entering the package 5.

[0060] In the optical device 1, when viewed from the Z-axis direction, the outer edge 12E of the light-shielding layer 12 is located outside the outer edge 55E of the opening 55a defined by the opening 5a. This makes it possible to prevent light from entering the package 5 from any point other than the light passage opening 120 of the optical element 10.

[0061] In the optical device 1, when viewed from the Z-axis direction, the outer edge 14E of the second multilayer filter 14 is located outside the outer edge 55E of the opening 55a defined by the opening 5a. This prevents light from entering the package 5 even if the light enters the light-transmitting substrate 11 from the side surface 11c of the light-transmitting substrate 11.

[0062] In the optical device 1, the optical element 10 is disposed in the opening 5a with the second surface 11b positioned closer to the Fabry-Perot interference filter 2 than the first surface 11a. This increases the distance between the light passing opening 120 of the light-shielding layer 12 and the Fabry-Perot interference filter 2, making it possible to limit the angle of incidence of light incident on the Fabry-Perot interference filter 2.

[0063] In the optical device 1, the light-absorbing adhesive member 7 is in contact with the surface 55b of the package 5 and the side surface 10a of the optical element 10, and extends to the height of the light-shielding layer 12 in the Z-axis direction. This makes it possible to prevent light from entering the light-transmitting substrate 11 from the side surface 11c of the light-transmitting substrate 11. [Modification]

[0064] The present disclosure is not limited to the above-described embodiments. For example, as shown in (a) of Fig. 8, in the optical element 10, when viewed in a direction parallel to a straight line L that is the thickness direction of the light-transmitting substrate 11, the outer edge 12E of the light-shielding layer 12 may be located inside the outer edge 11E of the light-transmitting substrate 11, and the outer edge 13E of the first multilayer filter 13 may be located between the outer edge 12E of the light-shielding layer 12 and the outer edge 11E of the light-transmitting substrate 11. As shown in (b) of Fig. 8, in the optical element 10, when viewed in a direction parallel to the straight line L, the outer edge 12E of the light-shielding layer 12 may be located inside the outer edge 11E of the light-transmitting substrate 11, and the outer edge 13E of the first multilayer filter 13 may coincide with the outer edge 12E of the light-shielding layer 12. As shown in (c) of Figure 8, in the optical element 10, when viewed from a direction parallel to the line L, the outer edge 12E of the light-shielding layer 12 is located inside the outer edge 11E of the light-transmitting substrate 11, and the outer edge 13E of the first multilayer filter 13 may be located inside the outer edge 12E of the light-shielding layer 12.

[0065] As shown in Fig. 9A, in the optical element 10, the outer edge 12E of the light-shielding layer 12 and the outer edge 13E of the first multilayer filter 13 may extend to the outer edge 11E of the light-transmitting substrate 11. As shown in Fig. 9B, in the optical element 10, the outer edge 14E of the second multilayer filter 14 may be located inside the outer edge 11E of the light-transmitting substrate 11. In this case, the outer edge 14E of the second multilayer filter 14 may be located inside at least one of the outer edges 12E of the light-shielding layer 12 and the outer edge 13E of the first multilayer filter 13, or may be located outside at least one of the outer edges 12E of the light-shielding layer 12 and the outer edge 13E of the first multilayer filter 13. The configuration of the second multilayer filter 14 shown in Fig. 9B can be combined with the configuration of the first surface 11a side shown in each of Figs. 5, 8A, 8B, and 8C, and 9A.

[0066] 9A, when viewed from a direction parallel to the line L, if the outer edge 12E of the light-shielding layer 12 reaches the outer edge 11E of the light-transmitting substrate 11, when light is incident on the light-transmitting substrate 11 from the first surface 11a side, it is possible to prevent the light from entering the light-transmitting substrate 11 through the outer edge region of the first surface 11a. Also, when light is incident on the light-transmitting substrate 11 from the second surface 11b side, it is possible to prevent the light from exiting the light-transmitting substrate 11 through the outer edge region of the first surface 11a.

[0067] 10(a), in the optical element 10, a light-shielding layer 12 may be disposed on each of the first surface 11a and the second surface 11b of the light-transmitting substrate 11. In this case, the second multilayer filter 14 only needs to cover at least "a light-passing region of the second surface 11b of the light-transmitting substrate 11 that overlaps with the light-passing opening 120 on the second surface 11b side when viewed from a direction parallel to the straight line L" and "a light-shielding region of the surface 12a of the light-shielding layer 12 on the second surface 11b side that surrounds the light-passing opening 120 on the second surface 11b side when viewed from a direction parallel to the straight line L." The configuration of the light-shielding layer 12 and the second multilayer filter 14 on the second surface 11b side shown in FIG. 10(a) can be combined with the configurations on the first surface 11a side shown in each of FIGS. 5, 8(a), 8(b), and 8(c), and FIG. 9(a).

[0068] As shown in (b) of FIG. 10 , in the optical element 10, a light-absorbing layer 15 may be disposed on a surface 14a of the second multilayer filter 14 opposite the light-transmitting substrate 11. The light-absorbing layer 15 is formed in a rectangular film shape using, for example, black resin, black resist, black paint, an inorganic compound thin film, or the like. For example, the thickness of the light-absorbing layer 15 is approximately 0.05 to 20 μm. The light-absorbing layer 15 has a light-passing opening 150. The light-passing opening 150 is located on a straight line L. When viewed from a direction parallel to the straight line L, the light-passing opening 150 has, for example, a circular shape centered on the straight line L. For example, the diameter of the light-passing opening 150 is approximately 0.1 to 2 mm. As long as the light-absorbing layer 15 overlaps with the light-shielding layer 12 when viewed from a direction parallel to the straight line L, the position of the outer edge 15E of the light-absorbing layer 15 is arbitrary. According to the configuration of the second surface 11b side shown in Fig. 10(b), when the optical element 10 is placed in the opening 5a of the package 5 with the second surface 11b positioned closer to the Fabry-Perot interference filter 2 than the first surface 11a, stray light generated within the package 5 is absorbed by the light absorbing layer 15, thereby preventing the light from entering the light receiving region 3a of the photodetector 3. The configuration of the light absorbing layer 15 shown in Fig. 10(b) can be combined with the configurations of the first surface 11a side shown in each of Figs. 5, 8(a), 8(b), and 8(c), and 9(a). Furthermore, the configuration of the light absorbing layer 15 shown in Fig. 10(b) can be combined with the configurations of the second surface 11b side shown in each of Figs. 5, 9(b), and 10(a).

[0069] 10(c), in the optical element 10, the engraving 8 may be provided in the light-shielding region 12R of the light-shielding layer 12. That is, the engraving 8 may be provided in at least one of the light-shielding region 12R of the light-shielding layer 12 and the surrounding region 13R of the first multilayer filter 13. When the engraving 8 is provided in the light-shielding region 12R, the first multilayer filter 13 can function as a protective layer, thereby suppressing deterioration of the engraving 8 provided on the surface 12a of the light-shielding layer 12. Furthermore, it is possible to avoid impairment of the function of the first multilayer filter 13 due to the engraving 8 being provided on the surface 13a of the first multilayer filter 13.

[0070] In addition, when the marking 8 is applied to the light-shielding region 12R of the light-shielding layer 12, it is preferable that the first multilayer filter 13 be a short-pass filter and the second multilayer filter 14 be a long-pass filter. For example, when the optical device 1 measures light in the near-infrared range, if the first multilayer filter 13 is a short-pass filter that selectively transmits light with wavelengths of 2000 nm or less, visible light (light with a wavelength of 380 to 780 nm) incident on the first multilayer filter 13 from the outside passes through the first multilayer filter 13, is reflected by the surface 12a of the light-shielding layer 12, and then passes through the first multilayer filter 13 to be emitted to the outside. On the other hand, the marking 8 has a rough surface, which easily scatters visible light. Thus, the light-shielding layer 12 has a high reflectance to visible light, while the marking 8 has a low reflectance to visible light. This contrast enhances the visibility of the marking 8 in visible light.

[0071] In the optical element 10, the inscription 8 may indicate, as the predetermined information, information other than "individual information of the Fabry-Perot interference filter 2" (for example, individual information of the light detecting element 3, individual information of the temperature compensating element 4, etc.). The inscription 8 may be something other than "letters and codes" as long as it indicates the predetermined information.

[0072] In the optical element 10, the engraving 8 may not be provided in either the surrounding region 13R of the first multilayer filter 13 or the light-shielding region 12R of the light-shielding layer 12. In this case, the surface 12a of the light-shielding layer 12 may not be light-reflective.

[0073] As shown in FIG. 11 , in the optical device 1, the side surface 10 a of the optical element 10 may be surrounded by a portion of the package 5. The package 5 shown in FIG. 11 differs from the package 5 shown in FIG. 1 in that a fifth layer 56 is laminated on a surface 55 b of a fourth layer 55. The fifth layer 56 is formed into a rectangular frame shape, for example, from ceramic or resin. When viewed in a direction parallel to the line L, the opening 56 a of the fifth layer 56 has a shape obtained by widening the opening 55 a of the fourth layer 55 on both sides in the X-axis direction and on both sides in the Y-axis direction. The optical element 10 is disposed in a region of the surface 55 b of the fourth layer 55 that is exposed through the opening 56 a of the fifth layer 56. The adhesive member 7 is disposed from the region between the surface 55 b of the package 5 and the outer edge portion of the optical element 10 to the region between the side surface 10 a of the optical element 10 and the side of the opening 56 a, and extends to the height of the light-shielding layer 12 in the direction parallel to the line L.

[0074] In the package 5 shown in FIG. 1 , the first layer 51, the second layer 53, the third layer 54, and the fourth layer 55 may be integrally formed. Alternatively, in the package 5 shown in FIG. 1 , at least one of the first layer 51, the second layer 53, the third layer 54, and the fourth layer 55 may be formed by stacking a plurality of layers. In the package 5 shown in FIG. 11 , the first layer 51, the second layer 53, the third layer 54, the fourth layer 55, and the fifth layer 56 may be integrally formed. Alternatively, in the package 5 shown in FIG. 11 , at least one of the first layer 51, the second layer 53, the third layer 54, the fourth layer 55, and the fifth layer 56 may be formed by stacking a plurality of layers.

[0075] In the optical element 10, the light-transmitting substrate 11 may be a substrate other than a silicon substrate (for example, a glass substrate). The light-transmitting substrate 11 may be formed of a material that is transparent to at least "light in the wavelength range that the optical element 10 should transmit."

[0076] In the optical device 1, the optical element 10 may be disposed in the opening 5a of the package 5 with the first surface 11a positioned closer to the Fabry-Perot interference filter 2 than the second surface 11b. In this case, since the light-shielding layer 12 is disposed on the Fabry-Perot interference filter 2 side of the light-transmitting substrate 11, even if light is incident on the light-transmitting substrate 11 from the side surface 11c of the light-transmitting substrate 11, the light can be prevented from entering the package 5 as it is.

[0077] In a configuration in which the optical element 10 is disposed in the opening 5a of the package 5 with the first surface 11a positioned closer to the Fabry-Perot interference filter 2 than the second surface 11b, light is incident on the light-transmitting substrate 11 from the second surface 11b side of the optical element 10. Even in this case, the light passage opening 120 of the light-shielding layer 12 can function as an aperture, while the light-transmitting substrate 11, the first multilayer filter 13, and the second multilayer filter 14 can function as bandpass filters. Furthermore, because the light-shielding layer 12 and the first multilayer filter 13 are disposed on the first surface 11a on the Fabry-Perot interference filter 2 side, even if light is incident on the light-transmitting substrate 11 from the side surface 11c of the light-transmitting substrate 11, the light can be prevented from emitting directly into the package 5. Moreover, since the first multilayer filter 13 is disposed on the first surface 11a and the second multilayer filter 14 is disposed on the second surface 11b, warping of the light-transmitting substrate 11 is less likely to occur, and as a result, the first multilayer filter 13 and the second multilayer filter 14 can function properly. Therefore, the optical element 10 can reliably transmit light in a predetermined wavelength range even when light is incident on the light-transmitting substrate 11 from the second surface 11b side.

[0078] In a configuration in which the optical element 10 is arranged at the opening 5a of the package 5 with the first surface 11a positioned on the Fabry-Perot interference filter 2 side relative to the second surface 11b, if the outer edge 14E of the second multilayer filter 14 is positioned outside the outer edge 12E of the light-shielding layer 12 when viewed from a direction parallel to the line L, when light is incident on the light-transmitting substrate 11 from the second surface 11b side, the light can be reliably transmitted through the second multilayer filter 14.

[0079] In a configuration in which the optical element 10 is arranged at the opening 5a of the package 5 with the first surface 11a positioned on the Fabry-Perot interference filter 2 side relative to the second surface 11b, if the outer edge 13E of the first multilayer filter 13 is positioned outside the outer edge 55E of the opening 55a defined by the opening 5a when viewed from the Z-axis direction, even if light enters the light-transmitting substrate 11 from the side surface 11c of the light-transmitting substrate 11, the light can be prevented from entering the package 5 directly.

[0080] The adhesive member 7 does not have to reach the height of the light-shielding layer 12 in the Z-axis direction. The adhesive member 7 may be disposed only in the region between the surface 55b of the package 5 and the surface of the optical element 10 on the surface 55b side.

[0081] 1...optical device, 2...Fabry-Perot interference filter, 2E...outer edge, 5...package, 5a...opening, 7...adhesive member, 10...optical element, 10a...side surface, 11...light-transmitting substrate, 11a...first surface, 11b...second surface, 11E...outer edge, 11R...light passing region, 12...light-shielding layer, 12a...surface, 12E...outer edge, 12R...light-shielding region, 13...first multilayer filter, 13E...outer edge, 14...second multilayer filter, 14E...outer edge, 35...first mirror portion (mirror portion), 36...second mirror portion (mirror portion), 55a...opening, 55b...surface (mounting surface), 55E...outer edge, 120...light passing opening, 120E...outer edge.

Claims

1. An optical element comprising: a light-transmitting substrate having a first surface and a second surface opposite the first surface; a light-shielding layer disposed on the first surface and having a light-passing opening; a first multilayer filter disposed on the first surface and covering a light-passing region of the first surface that overlaps with the light-passing opening when viewed in the thickness direction of the light-transmitting substrate, and a light-shielding region of the surface of the light-shielding layer opposite the light-transmitting substrate that surrounds the light-passing opening when viewed in the thickness direction of the light-transmitting substrate; and a second multilayer filter disposed on the second surface that overlaps with the light-passing region and the light-shielding region when viewed in the thickness direction of the light-transmitting substrate.

2. The optical element according to claim 1, wherein the light-transmitting substrate is a silicon substrate.

3. An optical element according to claim 1 or 2, wherein, when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the light-shielding layer is located inside the outer edge of the light-transmitting substrate, and when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the first multilayer filter is located outside the outer edge of the light-shielding layer.

4. The optical element according to claim 1 or 2, wherein, when viewed in the thickness direction of the light-transmitting substrate, the outer edge of the light-shielding layer extends to the outer edge of the light-transmitting substrate.

5. An optical element according to any one of claims 1 to 4, wherein, when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the second multilayer filter is located outside the outer edge of the light-shielding layer.

6. An optical device comprising: an optical element according to any one of claims 1 to 5; a package having an opening in which the optical element is disposed; and a Fabry-Perot interference filter disposed within the package and including a pair of mirror sections the distance between which is variable, wherein when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the light-passing opening is located inside the outer edge of the Fabry-Perot interference filter.

7. The optical device according to claim 6, wherein, when viewed in the thickness direction of the light-transmitting substrate, the outer edge of the light-shielding layer is located outside the outer edge of the opening defined by the opening.

8. An optical device as described in claim 6 or 7, wherein, when viewed from the thickness direction of the light-transmitting substrate, the outer edge of the first multilayer filter or the outer edge of the second multilayer filter is located outside the outer edge of the opening defined by the opening.

9. An optical device according to any one of claims 6 to 8, wherein the optical element is disposed in the opening with the second surface positioned on the Fabry-Perot interference filter side relative to the first surface.

10. An optical device as described in claim 9, further comprising an adhesive member having light absorption properties, wherein the optical element is placed on a mounting surface of the package, and the adhesive member is in contact with the mounting surface of the package and the side surface of the optical element, and extends to the height of the light-shielding layer in the thickness direction of the light-transmitting substrate.

11. An optical device according to any one of claims 6 to 8, wherein the optical element is disposed in the opening with the first surface positioned on the Fabry-Perot interference filter side relative to the second surface.

Images