Fabry-perot interferometer

Abstract

To manufacture a Fabry-Perot interferometer easily.SOLUTION: A first substrate 110 includes, on a first principal surface 111, a first reflection surface part 112 and a first reference surface part 113 positioned round the first reflection surface part 112. A second substrate 120 includes, on a second principal surface 121, a second reflection surface part 122 facing the first reflection surface part 112 with a gap L, and a second reference surface part 123 positioned around the second reflection surface part 122. A drive mechanism part 130 displaces the second reflection surface part 122 with respect to the first reflection surface part 112 in a state where the second reflection surface part 122 faces the first reflection surface part 112. An adhesion layer 140 contains at least three spacer particles 141 which are held between the first reference surface part 113 and the second reference surface part 123 for regulating a fixed gap D between the first reference surface part 113 and the second reference surface part 123.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a Fabry-Perot interferometer. [Background technology]

[0002] A prior art document disclosing a method for manufacturing a Fabry-Perot interference filter is Japanese Patent No. 6341959 (Patent Document 1). In the Fabry-Perot filter described in Patent Document 1, a gap is formed by removing a portion of a sacrificial layer by etching. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6341959 Summary of the Invention [Problem to be solved by the invention]

[0004] The method for manufacturing a Fabry-Perot interferometer described in Patent Document 1 involves complicated steps, and materials must be selected taking into consideration their resistance to etching solutions, making it difficult to manufacture a Fabry-Perot interferometer.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to provide a Fabry-Perot interferometer that can be easily manufactured. [Means for solving the problem]

[0006] A Fabry-Perot interferometer according to the present invention comprises a first substrate, a second substrate, a drive mechanism, and an adhesive layer. The first substrate has a first reflecting surface and a first reference surface located around the first reflecting surface on its first main surface. The second substrate has a second reflecting surface facing the first reflecting surface at a distance and a second reference surface located around the second reflecting surface on its second main surface. The drive mechanism displaces the second reflecting surface relative to the first reflecting surface while the second reflecting surface faces the first reflecting surface. The adhesive layer contains at least three spacer particles sandwiched between the first and second reference surfaces to define a constant distance between the first and second reference surfaces. [Effects of the Invention]

[0007] According to the present invention, a Fabry-Perot interferometer can be easily manufactured. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view of a Fabry-Perot interferometer according to a first embodiment of the present invention. [Figure 2] 2 is a cross-sectional view of the Fabry-Perot interferometer of FIG. 1, seen from the direction of the arrows along line II-II. [Figure 3] 10 is a flowchart illustrating an example of a method for manufacturing a Fabry-Perot interferometer. [Figure 4] FIG. 4 is a cross-sectional view of a Fabry-Perot interferometer according to a modified example of the first embodiment of the present invention. [Figure 5] FIG. 10 is a plan view of a Fabry-Perot interferometer according to a second embodiment of the present invention. [Figure 6] 6 is a cross-sectional view of the Fabry-Perot interferometer of FIG. 5, seen from the direction of the arrows along line VI-VI. [Figure 7] FIG. 10 is a plan view of a Fabry-Perot interferometer according to a first modification of the second embodiment of the present invention. [Figure 8] FIG. 10 is a plan view of a Fabry-Perot interferometer according to a second modification of the second embodiment of the present invention. [Figure 9] FIG. 10 is a plan view of a Fabry-Perot interferometer according to a third embodiment of the present invention. [Figure 10] 10 is a cross-sectional view of the Fabry-Perot interferometer of FIG. 9 as viewed from the direction of the arrow XX. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a Fabry-Perot interferometer according to each embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same or corresponding parts in the drawings are given the same reference numerals, and description thereof will not be repeated.

[0010] (Embodiment 1) Fig. 1 is a plan view of a Fabry-Perot interferometer according to a first embodiment of the present invention, and Fig. 2 is a cross-sectional view of the Fabry-Perot interferometer of Fig. 1 as viewed from the direction of the arrows along line II-II.

[0011] 1 and 2, a Fabry-Perot interferometer 100 according to the first embodiment of the present invention includes a first substrate 110, a second substrate 120, a drive mechanism 130, and an adhesive layer 140. The first substrate 110 has a first reflecting surface 112 and a first reference surface 113 located around the first reflecting surface 112 on its first main surface 111. The second substrate 120 has a second reflecting surface 122 facing the first reflecting surface 112 across a distance L, and a second reference surface 123 located around the second reflecting surface 122 on its second main surface 121. The drive mechanism 130 displaces the second reflecting surface 122 relative to the first reflecting surface 112 while the second reflecting surface 122 faces the first reflecting surface 112. The adhesive layer 140 contains at least three spacer particles 141 that are sandwiched between the first reference surface portion 113 and the second reference surface portion 123 to define a constant distance D between the first reference surface portion 113 and the second reference surface portion 123.

[0012] Each of first substrate 110 and second substrate 120 is made of, for example, silicon, quartz, or borosilicate glass. Each of first substrate 110 and second substrate 120 is translucent. Translucency refers to the property of transmitting at least a portion of electromagnetic waves, including light.

[0013] A first reflecting surface portion 112 is located in the center of a first main surface 111 of the first substrate 110. In this embodiment, the first reflecting surface portion 112 is circular. A ring-shaped first reference surface portion 113 is located on the first main surface 111 of the first substrate 110 so as to surround the first reflecting surface portion 112.

[0014] A second reflecting surface portion 122 is located in the center of a second main surface 121 of the second substrate 120. In this embodiment, the second reflecting surface portion 122 is circular. A ring-shaped second reference surface portion 123 is located on the second main surface 121 of the second substrate 120 so as to surround the second reflecting surface portion 122. Two approximately semicircular arc-shaped through grooves 124 are formed in the second substrate 120 along the outer periphery of the second reflecting surface portion 122. A beam portion 125 connecting the second reflecting surface portion 122 and the second reference surface portion 123 is formed between the ends of the two through grooves 124.

[0015] A reflective film having the property of selectively transmitting electromagnetic waves is formed on each of the first reflective surface portion 112 and the second reflective surface portion 122. The reflective film constitutes, for example, a Fabry-Perot etalon. The reflective film is, for example, a thin film made of Ag or an alloy containing Ag, and is a reflective film having transparency.

[0016] A driving mechanism 130 is formed on the beam 125. In this embodiment, the driving mechanism 130 includes a piezoelectric body. When a voltage is applied to the driving mechanism 130, the beam 125 is bent by piezoelectric driving, and the second reflecting surface 122 is displaced so as to move closer to or away from the first reflecting surface 112. As a result, the distance L between the first reflecting surface 112 and the second reflecting surface 122 is changed according to the voltage applied to the driving mechanism 130. Note that the driving mechanism 130 may be configured to displace the second reflecting surface 122 so as to move closer to the first reflecting surface 112 by electrostatic driving.

[0017] In this embodiment, the dimension of the distance L between the first reflecting surface portion 112 and the second reflecting surface portion 122 when no voltage is applied to the driving mechanism portion 130 is the same as the dimension of the fixed distance D between the first reference surface portion 113 and the second reference surface portion 123. However, the dimension of the distance L between the first reflecting surface portion 112 and the second reflecting surface portion 122 when no voltage is applied to the driving mechanism portion 130 may be smaller than the dimension of the fixed distance D between the first reference surface portion 113 and the second reference surface portion 123 by the thickness of the reflective film of the first reflecting surface portion 112 and the second reflecting surface portion 122.

[0018] The adhesive layer 140 is composed of at least three spacer particles 141 and an adhesive 142. The adhesive 142 bonds the first reference surface portion 113 of the first substrate 110 and the second reference surface portion 123 of the second substrate 120. The adhesive 142 is, for example, an epoxy adhesive, an acrylic adhesive, a silicone adhesive, or a polyurethane adhesive.

[0019] In this embodiment, the spacer particles 141 are spherical and have a diameter equal to the constant interval D. However, the shape of the spacer particles 141 may also be an oblate ellipsoid having a height equal to the constant interval D. The dimension of the constant interval D is, for example, not less than 0.5 μm and not more than 20 μm.

[0020] The adhesive layer 140 contains a large number of spacer particles 141. In principle, if the adhesive layer 140 contains three spacer particles 141, it is possible to define a constant distance D between the first reference surface portion 113 and the second reference surface portion 123. From the viewpoint of maintaining a uniform constant distance D between the first reference surface portion 113 and the second reference surface portion 123, it is preferable that at least three spacer particles 141 are arranged so as to surround the facing region where the first reflecting surface portion 112 and the second reflecting surface portion 122 face each other. In particular, from the viewpoint of maintaining a uniform constant distance D between the first reference surface portion 113 and the second reference surface portion 123, it is preferable that at least three spacer particles 141 are arranged so that the center of the facing region where the first reflecting surface portion 112 and the second reflecting surface portion 122 face each other is surrounded by a region formed by connecting the centers of the at least three spacer particles 141 in a plan view such as that shown in FIG. 1 .

[0021] The spacer particles 141 are metal particles, resin particles, glass particles, silica particles, or resin particles, glass particles, or silica particles covered with a metal coating. Examples of materials constituting the metal particles and metal coating include metals such as Au, Ag, Pt, Ni, Cu, Al, W, Pd, Mo, Ru, and Ti, or alloys thereof. The metal coating is not limited to a single layer, but may also be a multilayer coating. Examples of materials constituting the resin particles include epoxy resin, acrylic resin, and polypropylene resin. The Young's modulus of the spacer particles 141 is, for example, 1 GPa or more and 300 GPa or less.

[0022] Here, the operation of the Fabry-Perot interferometer 100 will be described. Light incident from the principal surface of the first substrate 110 opposite to the first principal surface 111 is transmitted through the first substrate 110 and the reflective film of the first reflecting surface 112. This input light is multiple-reflected between the first reflecting surface 112 and the second reflecting surface 122. At this time, light of the input light having a wavelength corresponding to the optical gap, which is the distance L between the first reflecting surface 112 and the second reflecting surface 122, remains, while light of other wavelengths is attenuated. This remaining light passes through the reflective film of the second reflecting surface 122 and the second substrate 120 as selected light and is emitted. In this way, the Fabry-Perot interferometer 100 can selectively emit only light of a specific wavelength from the incident light.

[0023] In order to make it possible to change the distance L between the first reflecting surface portion 112 and the second reflecting surface portion 122, the adhesive layer 140 is not located in the opposing region R where the first reflecting surface portion 112 and the second reflecting surface portion 122 face each other.

[0024] Next, a method for manufacturing the Fabry-Perot interferometer 100 will be described. FIG. 3 is a flowchart illustrating an example of a method for manufacturing a Fabry-Perot interferometer. First, a first substrate 110 having a first reflecting surface portion 112 formed thereon and a second substrate 120 having a second reflecting surface portion 122 formed thereon are prepared. Next, as shown in FIG. 3, an adhesive 142 having a large number of spacer particles 141 mixed therein is applied to at least one of a first reference surface portion 113 of a first main surface 111 of the first substrate 110 and a second reference surface portion 123 of a second main surface 121 of the second substrate 120 (S1). The application method may be screen printing or dispensing using a dispenser.

[0025] Next, the adhesive 142 is temporarily hardened (S2). In this embodiment, the adhesive 142 is temporarily hardened by heating. However, depending on the type of adhesive 142, the adhesive 142 may be softened by heating.

[0026] Next, the first reflecting surface portion 112 of the first main surface 111 of the first substrate 110 and the second reflecting surface portion 122 of the second main surface 121 of the second substrate 120 are aligned so as to face each other, and the first reference surface portion 113 and the second reference surface portion 123 are bonded together with adhesive 142, and the first substrate 110 and the second substrate 120 are sandwiched from the outside and pressurized (S3).

[0027] As a result, the spacer particle 141 is sandwiched between the first reference surface portion 113 and the second reference surface portion 123, and the distance between the first reference surface portion 113 and the second reference surface portion 123 is determined to be constant by the diameter of the spacer particle 141. When the spacer particle 141 is an oblate ellipsoid, the pressure conditions are optimized so that the minor axis is the dimension in the height direction, and the distance between the first reference surface portion 113 and the second reference surface portion 123 is determined to be constant by the minor axis of the spacer particle 141.

[0028] Next, the adhesive 142 is fully cured (S4). In this embodiment, the adhesive 142 is fully cured by heating. This maintains a constant distance D between the first reference surface portion 113 and the second reference surface portion 123.

[0029] Finally, the drive mechanism 130 is formed. The drive mechanism 130 may be formed on the first substrate 110 and the second substrate 120 in advance.

[0030] The Fabry-Perot interferometer 100 according to this embodiment is manufactured through the above series of steps. In the Fabry-Perot interferometer 100 according to this embodiment, the steps are simple, and there is no need to select materials taking into consideration resistance to etching solutions, so the Fabry-Perot interferometer 100 can be manufactured easily.

[0031] When the spacer particles 141 are made of resin particles, the moldability is better and the diameter of the spacer particles 141 is easier to control than when the spacer particles 141 are made of metal particles. Furthermore, since resin has higher chemical resistance than metal, the range of options for the manufacturing process of the Fabry-Perot interferometer 100 can be expanded. Furthermore, since resin has higher oxidation resistance and corrosion resistance than metal, the long-term stability of the Fabry-Perot interferometer 100 can be ensured. Furthermore, since resin has lower thermal conductivity than metal, the thermal influence between the first substrate 110 and the second substrate 120 can be reduced.

[0032] 4 is a cross-sectional view of a Fabry-Perot interferometer according to a modification of the first embodiment of the present invention. In a Fabry-Perot interferometer 100a according to a modification of the first embodiment of the present invention, a drive mechanism displaces the second reflecting surface portion 122 so as to approach the first reflecting surface portion 112 by electrostatic drive. The spacer particles 141 are metal particles. In this modification, at least one of the at least three spacer particles 141 is conductive and forms part of an electrical path in the Fabry-Perot interferometer 100a.

[0033] 4, a first escape wiring 131 and a second escape wiring 132 are formed on the second substrate 120. The first escape wiring 131 is connected to a first electrode 133 formed on the second main surface 121 of the second substrate 120. The second escape wiring 132 is connected to a second electrode 134 formed on the second main surface 121 of the second substrate 120. A third electrode 135 is formed on the first main surface 111 of the first substrate 110. The second electrode 134 and the third electrode 135 are electrically connected via spacer particles 141. The first electrode 133 and a portion of the third electrode 135 face each other with a gap therebetween.

[0034] When a voltage is applied between the first escape wiring 131 and the second escape wiring 132, an electrostatic force is generated between the first electrode 133 and a part of the third electrode 135, and the second reflecting surface 122 is displaced so as to approach the first reflecting surface 112. In this way, when the spacer particles 141 are metal particles, it is possible to aggregate the escape wiring on the first substrate 110 or the second substrate 120, which simplifies the manufacture of the Fabry-Perot interferometer 100a. Note that the electrical path of which the spacer particles 141 form a part is not limited to an electrical path that applies a voltage between electrodes for electrostatic drive, but may also be an electrical path that detects electrostatic capacitance between electrodes to measure the dimension of the gap L between the first reflecting surface 112 and the second reflecting surface 122.

[0035] 4, a third escape wiring 136 and a fourth escape wiring 137 are formed on the second substrate 120. The third escape wiring 136 is connected to a fourth electrode 138 formed on an edge of the second reflecting surface portion 122 of the second substrate 120. The fourth escape wiring 137 is connected to a fifth electrode 139 formed on the second main surface 121 of the second substrate 120. A sixth electrode 170 is formed on the first main surface 111 of the first substrate 110. The fifth electrode 139 and the sixth electrode 170 are electrically connected via spacer particles 141. A part of the sixth electrode 170 located on the edge of the first reflecting surface portion 112 and the fourth electrode 138 face each other with a gap therebetween.

[0036] The distance L between the first reflecting surface portion 112 and the second reflecting surface portion 122 can be measured by detecting the capacitance between the fourth electrode 138 and the sixth electrode 170 using a measuring device connected to the third escape wiring 136 and the fourth escape wiring 137. When the spacer particles 141 are metal particles, the escape wiring can be concentrated on the first substrate 110 or the second substrate 120, simplifying the manufacture of the Fabry-Perot interferometer 100a. The fourth electrode 138 and the sixth electrode 170 are each located at the edge of the facing region R, thereby suppressing their influence on optical interference in the facing region R. The driving method used by the driving mechanism according to this modification is not limited to electrostatic driving, and may be piezoelectric driving.

[0037] As shown in FIG. 4, in the Fabry-Perot interferometer 100a, a sensor 150 is provided on the main surface of the second substrate 120 opposite to the second main surface 121. The sensor 150 is a sensor that detects the wavelength of the selected light, and is, for example, an optical sensor, a temperature sensor, or a pyroelectric sensor. When the sensor 150 is a temperature sensor, a light absorption layer that absorbs the selected light is formed on the second substrate 120, and the sensor 150 detects the temperature when the light absorption layer absorbs the selected light and generates heat, thereby indirectly detecting the wavelength of the selected light. When the sensor 150 is a pyroelectric sensor, the sensor 150 detects an electric charge generated by a temperature change when the selected light is incident on the sensor 150, thereby indirectly detecting the wavelength of the selected light.

[0038] When the sensor 150 is a temperature sensor or a pyroelectric sensor, the spacer particles 141 are metal particles, which increases the heat dissipation from the second substrate 120 to the first substrate 110 via the spacer particles 141, thereby shortening the detection interval by the sensor 150.

[0039] The large amount of spacer particles 141 may be a mixture of metal particles, resin particles, glass particles, silica particles, or resin particles, glass particles, or silica particles coated with a metal film, and each may be arranged according to the application. That is, metal spacer particles 141 may be arranged in areas where conductivity and high heat dissipation are required, resin spacer particles 141 may be arranged in areas where insulation is required, and resin, glass, or silica spacer particles 141 coated with a metal film may be arranged in areas where conductivity and moderate heat dissipation are required.

[0040] (Embodiment 2) A Fabry-Perot interferometer according to a second embodiment of the present invention will be described below with reference to the drawings. Note that the Fabry-Perot interferometer according to the second embodiment of the present invention differs from Fabry-Perot interferometer 100 according to the first embodiment in that a convex portion that prevents the adhesive layer from extending into the opposing region is formed on at least one of the first and second principal surfaces. Therefore, description of the same configuration as Fabry-Perot interferometer 100 according to the first embodiment will not be repeated.

[0041] Fig. 5 is a plan view of a Fabry-Perot interferometer according to embodiment 2 of the present invention, and Fig. 6 is a cross-sectional view of the Fabry-Perot interferometer of Fig. 5 as viewed in the direction of the arrows along line VI-VI.

[0042] 5 and 6, in Fabry-Perot interferometer 200 according to embodiment 2 of the present invention, convex portions that prevent adhesive layer 140 from extending into facing region R are formed on both first reference surface portion 113 of first main surface 111 of first substrate 110 and second reference surface portion 123 of second main surface 121 of second substrate 120. The convex portions are made of a material such as solder resist that is resistant to adhesive 142.

[0043] Specifically, on the first reference surface portion 113 of the first main surface 111 of the first substrate 110, an annular convex portion 151 is formed along a position corresponding to the outer edges of the two through grooves 124, and an annular convex portion 152 is formed to surround the convex portion 151 with a gap therebetween. On the second reference surface portion 123 of the second main surface 121 of the second substrate 120, an annular convex portion 161 is formed along the outer edges of the two through grooves 124, and an annular convex portion 162 is formed to surround the convex portion 161 with a gap therebetween. Note that the convex portions 151 and 161 are formed at positions and with height dimensions such that they do not contact each other. The convex portions 152 and 162 are formed at positions and with height dimensions such that they do not contact each other.

[0044] However, without being limited to the above embodiment, it is sufficient that a convex portion that prevents the adhesive layer 140 from extending into the opposing region R is formed on at least one of the first reference surface portion 113 of the first main surface 111 of the first substrate 110 and the second reference surface portion 123 of the second main surface 121 of the second substrate 120.

[0045] The height dimension of each of the protrusions 151, 152, 161, and 162 is between ¼ and ¾ of the dimension of the constant distance D. This prevents the spacer particles 141 and the adhesive 142 from entering the facing region R and the region between the beam portion 125 and the first main surface 111. Even if the protrusions 151, 152, 161, and 162 are formed, the constant distance D between the first reference surface portion 113 and the second reference surface portion 123 can be determined by the spacer particles 141. This improves the stability of the Fabry-Perot interferometer 200. The height dimensions of the protrusions 151, 152, 161, and 162 do not have to be the same.

[0046] FIG. 7 is a plan view of a Fabry-Perot interferometer according to Modification 1 of Embodiment 2 of the present invention. As shown in FIG. 7, in a Fabry-Perot interferometer 200a according to Modification 1 of Embodiment 2 of the present invention, four elliptical ring-shaped convex portions 161 are formed on the second reference surface portion 123 of the second main surface 121 of the second substrate 120 so as to surround the second reflecting surface portion 122. An adhesive layer 140 is formed in the inner region of each of the four convex portions 161. The number of convex portions 161 is not limited to four and may be one or more. However, it is preferable that three or more convex portions 161 are positioned at equal intervals in the circumferential direction surrounding the second reflecting surface portion 122. Similarly to the convex portions 161, convex portions 151 may also be formed on the first reference surface portion 113 of the first main surface 111 of the first substrate 110 so as not to come into contact with the convex portions 161.

[0047] In the Fabry-Perot interferometer 200a as well, the spacer particles 141 and adhesive 142 can be prevented from entering the facing region R and the region between the beam portion 125 and the first main surface 111. Furthermore, even if the convex portions 151 and 161 are formed, the constant distance D between the first reference surface portion 113 and the second reference surface portion 123 can be defined by the spacer particles 141. These features can improve the stability of the Fabry-Perot interferometer 200a.

[0048] FIG. 8 is a plan view of a Fabry-Perot interferometer according to Modification 2 of Embodiment 2 of the present invention. As shown in FIG. 8, in a Fabry-Perot interferometer 200b according to Modification 2 of Embodiment 2 of the present invention, four semi-elliptical ring-shaped convex portions 161, which are open on the side opposite to the second reflecting surface portion 122 side, are formed on the second reference surface portion 123 of the second main surface 121 of the second substrate 120 so as to surround the second reflecting surface portion 122. An adhesive layer 140 is formed in the inner region of each of the four convex portions 161. The number of convex portions 161 is not limited to four and may be one or more. However, it is preferable that three or more convex portions 161 are positioned at equal intervals in the circumferential direction surrounding the second reflecting surface portion 122. Similarly to the convex portions 161, convex portions 151 may also be formed on the first reference surface portion 113 of the first main surface 111 of the first substrate 110 so as not to come into contact with the convex portions 161.

[0049] In Fabry-Perot interferometer 200b as well, it is possible to prevent spacer particles 141 and adhesive 142 from entering facing region R and the region between beam portion 125 and first main surface 111. Furthermore, even if convex portions 151 and 161 are formed, constant distance D between first reference surface portion 113 and second reference surface portion 123 can be defined by spacer particles 141. These features can improve the stability of Fabry-Perot interferometer 200b.

[0050] (Embodiment 3) A Fabry-Perot interferometer according to a third embodiment of the present invention will be described below with reference to the drawings. Note that the Fabry-Perot interferometer according to the third embodiment of the present invention differs from Fabry-Perot interferometer 100 according to the first embodiment in that a recess is formed in at least one of the first and second principal surfaces to prevent the adhesive layer from extending into the opposing region. Therefore, description of the same configuration as that of Fabry-Perot interferometer 100 according to the first embodiment will not be repeated.

[0051] Fig. 9 is a plan view of a Fabry-Perot interferometer according to a third embodiment of the present invention, and Fig. 10 is a cross-sectional view of the Fabry-Perot interferometer of Fig. 9 as viewed from the direction of the arrow XX.

[0052] 9 and 10 , in a Fabry-Perot interferometer 300 according to the third embodiment of the present invention, recesses that prevent the adhesive layer 140 from extending into the facing region R are formed in both the first reference surface portion 113 of the first main surface 111 of the first substrate 110 and the second reference surface portion 123 of the second main surface 121 of the second substrate 120. The recesses can be formed by etching or laser light irradiation.

[0053] Specifically, in the first reference surface portion 113 of the first main surface 111 of the first substrate 110, an annular recess 153 is formed along a position corresponding to the outer edges of the two through grooves 124, and an annular recess 154 is formed to surround the recess 153 with a gap therebetween. In the second reference surface portion 123 of the second main surface 121 of the second substrate 120, an annular recess 163 is formed along the outer edges of the two through grooves 124, and an annular recess 164 is formed to surround the recess 163 with a gap therebetween.

[0054] This makes it possible to prevent the spacer particles 141 and adhesive 142 from entering the facing region R and the region between the beam portion 125 and the first main surface 111. Furthermore, even if the recesses 153, 154, 163, and 164 are formed, the constant distance D between the first reference surface portion 113 and the second reference surface portion 123 can be defined by the spacer particles 141. This improves the stability of the Fabry-Perot interferometer 300. Note that the depth and width dimensions of the recesses 153, 154, 163, and 164 do not have to be the same.

[0055] However, without being limited to the above embodiment, it is sufficient that a recess is formed in at least one of the first reference surface portion 113 of the first main surface 111 of the first substrate 110 and the second reference surface portion 123 of the second main surface 121 of the second substrate 120 to prevent the adhesive layer 140 from extending into the opposing region R.

[0056] The arrangement of the recesses may be the same as the arrangement of the protrusions in Modifications 1 and 2 of Embodiment 2. The recesses in Embodiment 3 and the protrusions in Embodiment 2 may be arranged in combination as appropriate.

[0057] (Addendum) It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0058] <1> a first substrate having, on a first main surface thereof, a first reflecting surface portion and a first reference surface portion located around the first reflecting surface portion; a second substrate having, on a second main surface thereof, a second reflecting surface portion facing the first reflecting surface portion with a gap therebetween and a second reference surface portion positioned around the second reflecting surface portion; a drive mechanism that displaces the second reflecting surface portion relative to the first reflecting surface portion in a state where the second reflecting surface portion faces the first reflecting surface portion; a Fabry-Perot interferometer comprising an adhesive layer sandwiched between the first reference surface portion and the second reference surface portion and containing at least three spacer particles that define a constant distance between the first reference surface portion and the second reference surface portion.

[0059] <2> the adhesive layer is not located in an opposing region where the first reflecting surface portion and the second reflecting surface portion face each other. <1> Fabry-Perot interferometer as described in

[0060] <3> a convex portion that prevents the adhesive layer from extending into the facing region is formed on at least one of the first reference surface portion of the first main surface and the second reference surface portion of the second main surface, The height of the convex portion is ¼ to ¾ of the dimension of the fixed interval. <1> or <2> Fabry-Perot interferometer as described in

[0061] <4> a recess formed in at least one of the first reference surface portion of the first main surface and the second reference surface portion of the second main surface, the recess preventing the adhesive layer from extending into the opposing region; <1> from <3> 10. The Fabry-Perot interferometer according to any one of claims 1 to 9.

[0062] <5> The Young's modulus of each of the at least three spacer particles is 1 GPa or more and 300 GPa or less. <1> from <4> 10. The Fabry-Perot interferometer according to any one of claims 1 to 9.

[0063] <6> Each of the at least three spacer particles is a metal particle, a resin particle, a glass particle, a silica particle, or a resin particle, a glass particle, or a silica particle coated with a metal coating. <1> from <5> 10. The Fabry-Perot interferometer according to any one of claims 1 to 9.

[0064] <7> At least one of the at least three spacer particles is electrically conductive and forms a part of an electrical path in the Fabry-Perot interferometer. <1> from <6> 10. The Fabry-Perot interferometer according to any one of claims 1 to 9.

[0065] <8> a first lead-out wiring and a second lead-out wiring are formed on the second substrate; the first interconnection is connected to a first electrode formed on the second main surface, the second interconnection is connected to a second electrode formed on the second main surface, a third electrode is formed on the first main surface; the second electrode and the third electrode are electrically connected through the at least one of the at least three spacer particles; <7> Fabry-Perot interferometer as described in

[0066] <9> a third escape wiring and a fourth escape wiring are formed on the second substrate; the third lead wiring is connected to a fourth electrode formed on an end of the second reflecting surface portion, the fourth interconnection is connected to a fifth electrode formed on the second main surface, a sixth electrode is formed on the first main surface; a part of the sixth electrode located at an end of the first reflecting surface portion and the fourth electrode face each other with a gap therebetween; the fifth electrode and the sixth electrode are electrically connected through the at least one of the at least three spacer particles; <7> Fabry-Perot interferometer as described in

[0067] In the above-described embodiments, configurations that can be combined may be combined with each other.

[0068] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0069] Fabry - Perot interferometers 100, 100a, 200, 200a, 200b, 300, first substrate 110, first main surface 111, first reflecting portion 112, first reference portion 113, second substrate 120, second main surface 121, second reflecting portion 122, second reference portion 123, through - groove 124, beam portion 125, drive mechanism portion 130, first lead wiring 131, second lead wiring 132, first electrode 133, second electrode 134, third electrode 135, third lead wiring 136, fourth lead wiring 137, fourth electrode 138, fifth electrode 139, adhesive layer 140, spacer particles 141, adhesive 142, sensor 150, convex portions 151, 152, 161, 162, concave portions 153, 154, 163, 164, sixth electrode 170, constant interval D, interval L, opposing region R.

Claims

1. a first substrate having, on a first main surface thereof, a first reflecting surface portion and a first reference surface portion located around the first reflecting surface portion; a second substrate having, on a second main surface thereof, a second reflecting surface portion facing the first reflecting surface portion with a gap therebetween and a second reference surface portion positioned around the second reflecting surface portion; a drive mechanism that displaces the second reflecting surface portion relative to the first reflecting surface portion in a state where the second reflecting surface portion faces the first reflecting surface portion; a Fabry-Perot interferometer comprising: an adhesive layer sandwiched between the first reference surface portion and the second reference surface portion and containing at least three spacer particles that define a constant distance between the first reference surface portion and the second reference surface portion.

2. 2. The Fabry-Perot interferometer according to claim 1, wherein the adhesive layer is not located in an opposing region where the first reflecting surface portion and the second reflecting surface portion face each other.

3. a convex portion that inhibits the adhesive layer from extending into the facing region is formed on at least one of the first reference surface portion of the first main surface and the second reference surface portion of the second main surface, 3. The Fabry-Perot interferometer according to claim 2, wherein the height of said convex portions is equal to or greater than 1 / 4 and equal to or less than 3 / 4 of the dimension of said fixed interval.

4. 3. The Fabry-Perot interferometer according to claim 2, wherein a recess is formed in at least one of the first reference surface portion of the first main surface and the second reference surface portion of the second main surface to prevent the adhesive layer from extending into the opposing region.

5. 5. The Fabry-Perot interferometer of claim 1, wherein the Young's modulus of each of the at least three spacer particles is equal to or greater than 1 GPa and equal to or less than 300 GPa.

6. 6. The Fabry-Perot interferometer of claim 5, wherein each of the at least three spacer particles is a metal particle, a resin particle, a glass particle, a silica particle, or a resin particle, a glass particle, or a silica particle coated with a metal coating.

7. 7. The Fabry-Perot interferometer of claim 6, wherein at least one of the at least three spacer particles is electrically conductive and forms part of an electrical path in the Fabry-Perot interferometer.

8. a first lead-out wiring and a second lead-out wiring are formed on the second substrate; the first interconnection is connected to a first electrode formed on the second main surface, the second interconnection is connected to a second electrode formed on the second main surface, a third electrode is formed on the first main surface; 8. The Fabry-Perot interferometer of claim 7, wherein the second electrode and the third electrode are electrically connected through the at least one of the at least three spacer particles.

9. a third escape wiring and a fourth escape wiring are formed on the second substrate; the third lead wiring is connected to a fourth electrode formed on an end of the second reflecting surface portion, the fourth interconnection is connected to a fifth electrode formed on the second main surface, a sixth electrode is formed on the first main surface; a part of the sixth electrode located at an end of the first reflecting surface portion and the fourth electrode face each other with a gap therebetween; 8. The Fabry-Perot interferometer of claim 7, wherein the fifth electrode and the sixth electrode are electrically connected through the at least one of the at least three spacer particles.

Images