Detection element, detection system, and method for manufacturing detection element

Abstract

This detection element comprises: a glass housing that includes a first surface and a second surface facing one another and forming a space; an internal antenna; an external antenna that is disposed on the side opposite a surface where the internal antenna is disposed so as to sandwich the housing therebetween and that is electrically connected to the internal antenna; and a piezoelectric vibrator that is disposed so as to be able to be vibrated near, or in contact with, the internal antenna by a first support member and / or a second support member. The housing comprises: a plurality of openings that open to the exterior of the housing and communicate with the space; and a channel that allows a fluid to communicate between the space and the plurality of openings.

Description

Detection element, detection system, and method for manufacturing a detection element

[0001] The present disclosure relates to a detection element, a detection system, and a method for manufacturing a detection element.

[0002] Conventionally, detection elements such as gas sensors and biosensors using crystal oscillators have been known. In these sensors, electrodes such as Au are provided on both sides of the crystal oscillator, and wirings are further connected to these electrodes. In order to increase the sensitivity, it is necessary to thin the crystal oscillator, but due to the influence of such electrodes and wirings, there has been a problem that the dynamic mass of the crystal oscillator itself does not decrease. In response to such a problem, as described in Patent Document 1, electrode-free and power supply-free detection elements in which electrodes and wirings are not provided on the crystal oscillator have been proposed.

[0003] Japanese Unexamined Patent Application Publication No. 2019-138628

[0004] The housing of the detection element described in Patent Document 1 has a three-layer structure in which a silicon substrate is sandwiched between glass substrates. Here, a detection element on which a crystal oscillator is mounted is packaged by joining a first structure including a glass substrate to which a silicon substrate is joined and a second structure including a glass substrate. However, the anodic bonding between the silicon substrate of the first structure and the glass substrate of the second structure is performed by applying a voltage of 600 V at a temperature of 350°C. Since the packaging process is performed in such a high-temperature environment, there is a possibility that the crystal oscillator may be damaged, and there is a problem of low yield.

[0005] The technology of the present disclosure has been made in view of the above-described circumstances, and an object thereof is to provide a highly sensitive detection element that can be manufactured with a high yield.

[0006] The detection element according to this disclosure comprises: a housing made of glass, including a first surface and a second surface facing each other and forming a space; an internal antenna portion disposed on at least one of the first surface and the second surface; an external antenna portion disposed on the opposite side of the housing from the surface on which the internal antenna portion is disposed, and electrically connected to the internal antenna portion; a first support member protruding from the first surface toward the second surface; a second support member protruding from the second surface toward the first surface; and a piezoelectric vibrator, vibrably disposed in the space by at least one of the first support member and the second support member in the vicinity of or in contact with the first internal antenna portion and / or the second internal antenna portion, wherein the housing has a plurality of openings opening to the outside of the housing and communicating with the space; and a flow path for communicating fluid between the space and the plurality of openings.

[0007] Here, the internal antenna section may be a single internal antenna section or may include multiple internal antenna sections. Similarly, the external antenna section may be a single external antenna section or may include multiple external antenna sections. That is, the internal antenna section may include a first internal antenna section and / or a second internal antenna section arranged on at least one of the first surface and the second surface. In this case, the external antenna section may include a first external antenna section arranged on the opposite side of the housing from the surface on which the first internal antenna section is arranged and electrically connected to the first internal antenna section, and a second external antenna section arranged on the opposite side of the housing from the surface on which the second internal antenna section is arranged and electrically connected to the second internal antenna section. In this case, the piezoelectric vibrator may be arranged in the space so as to vibrate near or in contact with the first internal antenna section and / or the second internal antenna section by at least one of the first support member and the second support member.

[0008] The housing may be constructed by laminating a first component made of glass, which includes the first surface, and a second component made of glass, which includes the second surface.

[0009] The detection system according to this disclosure comprises: a detection element; a transmitting and receiving device that transmits a transmission signal to the detection element and receives a reception signal from the detection element via wired or wireless means; and an analysis device that analyzes the reception signal and detects a temporal change in a predetermined indicator.

[0010] A method for manufacturing a detection element according to the present disclosure is a method for manufacturing a detection element comprising a housing having a space inside which a first surface and a second surface facing each other with a vibrably arranged piezoelectric vibrator in between, the method comprising: a step of manufacturing a first structure of the detection element, which includes a first component made of glass of the housing including the first surface; a step of manufacturing a second structure of the detection element, which includes a second component made of glass of the housing including the second surface; a step of arranging the piezoelectric vibrator to vibrate in either the first structure or the second structure; and a step of joining a first joint made of glass of the first structure and a second joint made of glass of the second structure to form the space.

[0011] The step of forming the space may be performed by joining the first joint and the second joint in a low-temperature environment.

[0012] The step of forming the space may be a step of joining the other of the first structure and the second structure to either the first structure or the second structure that holds the piezoelectric vibrator.

[0013] The step of forming the space may be a step of joining the first joint and the second joint by laser bonding.

[0014] According to this disclosure, it is possible to provide a highly sensitive detection element that can be manufactured with a good yield.

[0015] Figure 1 is a perspective view showing the schematic structure of the detection element according to the embodiment. Figure 2 is an exploded perspective view showing the schematic structure of the detection element according to the embodiment. Figure 3 is a cross-sectional view of the detection element according to the embodiment along line A-A. Figures 4(A) to 4(D) are plan and bottom views of the structure of the detection element according to the embodiment. Figures 5(A) to 5(F) are part of a process diagram showing the manufacturing method of the detection element according to the embodiment. Figures 6(A) to 6(E) are part of a process diagram showing the manufacturing method of the detection element according to the embodiment. Figure 7 is a schematic configuration diagram of the detection system according to Example 1. Figure 8 is a timing chart of the input voltage to the detection element and the received signal according to the embodiment. Figure 9 is a timing chart of the resonant frequency of the detection element according to the embodiment. Figure 10 is a schematic configuration diagram of the detection system according to Example 2.

[0016] A detection element and a method for manufacturing the same according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the configurations and combinations thereof in the embodiments are examples only, and additions, omissions, substitutions, and other modifications can be made as appropriate without departing from the spirit of the present disclosure. This disclosure is not limited by the embodiments, but is limited only by the claims.

[0017] <Example 1> Figure 1 is a perspective view showing the schematic structure of the detection element 100. Figure 2 is an exploded perspective view showing the schematic structure of the detection element 100. Figure 3 is a cross-sectional view of the detection element 100 along line A-A. Figures 4(A) and 4(B) are a plan view and a bottom view of structure 100A of the detection element 100, respectively. Figures 4(C) and 4(D) are a plan view and a bottom view of structure 100B of the detection element, respectively. Hereinafter, unless otherwise specified, the vertical direction on Figure 1 will be referred to as the vertical direction of the detection element 100 with respect to the orientation of the detection element 100 shown in Figure 1. Structure 100A corresponds to the first structure of this disclosure. Structure 100B corresponds to the second structure of this disclosure.

[0018] The detection element 100 has a rectangular parallelepiped shape with sides of 6 mm in plan view and a height of approximately 1 mm. The housing 10 of the detection element 100 has a laminated structure of glass substrates 20 and 40. Glass substrate 20 corresponds to the first component of this disclosure. Glass substrate 40 corresponds to the second component of this disclosure.

[0019] The glass substrate 20 has openings 22 and 23 that penetrate the glass substrate 20 in the thickness direction. Both openings 22 and 23 open to the outside on the surface (upper surface of the detection element) 21 of the glass substrate 20. The diameter of both openings 22 and 23 is 1 mm. Openings 22 and 23 correspond to the plurality of openings in this disclosure.

[0020] An external antenna portion 50 is provided on the surface 21 of the glass substrate 20, along the diagonal between the openings 22 and 23. The external antenna portion 50 can be formed by a laminated structure consisting of, for example, a titanium (Ti) or chromium (Cr) adhesion layer and a gold (Au) or platinum (Pt) electrode layer. The glass substrate 20 is also provided with cylindrical column portions 60 made of a conductive material that penetrate in the thickness direction of the glass substrate 20. In this case, five column portions 60 are provided. These column portions 60, together with the conductive film 70 and head portion 80 described later, constitute a support member 110. In this case, the support member 110 including the column portions 60 is arranged at the four corners and the center of the rectangular internal antenna portion 90 described later. The number and arrangement of the support member 110 including the column portions 60 are not limited to this. Also, although the shape of the support member 110 including the column portions 60 is cylindrical in this case, it is not limited to this and may be a prismatic shape with a polygonal cross-section or a plate shape. The column portion 60 can be formed from, for example, tungsten W. The external antenna portion 50 corresponds to the external antenna portion of this disclosure and the first external antenna portion. The support member 110 corresponds to the first support member of this disclosure.

[0021] A recess 24 is formed on the inner surface of the glass substrate 20 (the surface facing the glass substrate 40). This recess 24 is formed in the region from the opening 22 to the opening 23. At the bottom 24a of this recess 24, cylindrical conductive heads 80 are formed via a conductive film 70 formed in the region including each end of the columnar portion 60. Furthermore, an internal antenna portion 90 is provided at the bottom 24a of the recess 24, extending over the region covering the heads 80. This internal antenna portion 90 is electrically connected to the external antenna portion 50 by the heads 80, the conductive film 70, and the columnar portion 60. The columnar portion 60, the conductive film 70, and the heads 80 constitute the support member 110. The conductive film 70 is formed, for example, by coating chromium (Cr), titanium (Ti), etc., which have a coefficient of thermal expansion compatible with glass. The head portion 80 can be formed from a suitable material such as doped silicon (Si) or gold-silicon alloy (Au-Si), as long as it is a corrosion-resistant and conductive material. For example, it can be formed by laminating nickel or gold onto copper by plating using a conductive film 70. The internal antenna portion 90 is provided within the recess 24 so as to cover the bottom portion 24a of the recess 24 and the head portion 80 of the support member 110. The internal antenna portion 90 can be formed from a laminated structure consisting of, for example, an adhesion layer of titanium (Ti) or chromium (Cr) and an electrode layer of gold (Au) or platinum (Pt). The bottom portion 24a corresponds to the first surface of this disclosure. The internal antenna portion 90 corresponds to the internal antenna portion and the first internal antenna portion of this disclosure.

[0022] An external antenna portion 120 is provided on the surface (lower surface of the detection element 100) 41 of the glass substrate 40 along the diagonal. The external antenna portion 120 is provided in the same orientation as the external antenna portion 50 described above. The external antenna portion 120 can be formed by a laminated structure consisting of, for example, an adhesion layer of titanium (Ti) or chromium (Cr) and an electrode layer of gold (Au) or platinum (Pt). A recess 42 corresponding to the recess 24 of the glass substrate 20 is formed on the inner surface of the glass substrate 40 (the surface facing the glass substrate 20). The glass substrate 40 is also provided with a cylindrical column portion 130 made of a conductor that penetrates in the thickness direction. This column portion 130 also constitutes a support member 170 together with the conductive film 140 and head portion 150 described later. Here, the support member 170 including the column portion 130 is arranged at the four corners and the center of the rectangular internal antenna portion 180 described later. The number and arrangement of the support member 170 including the column portion 130 are not limited to this. Furthermore, although the shape of the support member 170 including the column portion 130 is cylindrical in this case, it is not limited to this and may be a prism shape with a polygonal cross-section or a plate shape. The column portion 130 can be formed from, for example, tungsten W. The external antenna portion 120 corresponds to the external antenna portion and the second external antenna portion of this disclosure. The support member 170 corresponds to the second support member of this disclosure.

[0023] The recess 42 of the glass substrate 40 is formed in the region from the opening 22 to the opening 23. At the bottom 42a of the recess 42, cylindrical conductive heads 150 are formed via a conductive film 160 formed in the region including each end of the columnar portion 130. Furthermore, an internal antenna portion 180 is provided at the bottom 42a of the recess 42, extending over the region covering the heads 150. This internal antenna portion 180 is electrically connected to the external antenna portion 120 by the heads 150, the conductive film 160, and the columnar portion 130. The conductive film 140 is formed of a conductor such as chromium (Cr). The heads 150 are, for example, corrosion-resistant conductive members made by laminating nickel or gold on copper. The heads 150 may also be formed of appropriate materials such as doped silicon (Si) or gold-silicon alloy (Au-Si). The internal antenna portion 180 is provided in the recess 42 so as to cover the bottom portion 42a and the head portion 150 of the support member 170. The internal antenna portion 180 also has a laminated structure consisting of, for example, an adhesion layer of titanium (Ti) or chromium (Cr) and an electrode layer of gold (Au) or platinum (Pt). The bottom portion 42a corresponds to the second surface of this disclosure. The internal antenna portion 180 corresponds to the internal antenna portion and the second internal antenna portion of this disclosure.

[0024] The housing 10 of the detection element 100 is provided with a space 11 in which the vibrator 200 is arranged to vibrate. The space 11 in which the vibrator 200 is arranged is provided between the bottom 24a of the opposing glass substrate 20 and the bottom 42a of the glass substrate 40. Since the housing 10 in which the vibrator 200 is arranged has a laminated structure of glass substrate 20 and glass substrate 40, as described later, packaging in a low-temperature environment without damaging the vibrator 200 is possible, and highly sensitive detection elements 100 can be manufactured with a high yield. The vibrator 200 has a rectangular planar shape. The housing 10 corresponds to the housing of this disclosure. The space 11 corresponds to the space of this disclosure. The vibrator 200 corresponds to the piezoelectric vibrator of this disclosure.

[0025] The oscillator 200 is made of, for example, quartz. The material of the oscillator 200 is not limited to quartz; any suitable piezoelectric material such as barium titanate or zirconate titanate can be used. The thickness of the oscillator 200 can be, for example, 17 to 23 μm, but it is preferable to have a thickness of 10 μm or less.

[0026] The transducer 200 is supported by contacting at least one of the support member 110 via the internal antenna section 90 and the support member 170 via the internal antenna section 180. Even if the transducer 200 does not directly contact at least one of the support member 110 via the internal antenna section 90 and the support member 170 via the internal antenna section 180, it is desirable that it be positioned in its immediate vicinity. Here, "contact" includes cases where it is fixed by joining, bonding, etc., but it is preferable that it is in contact without being fixed. Since the transducer 200 is supported by at least one of the support member 110 and the support member 170, even if it bends, it is prevented from contacting the bottom 24a of the recess 24 or the bottom 42a of the recess 42. The number and arrangement of the support members 110 and 170 can be appropriately selected to prevent contact with the bottom 24a of the recess 24 or the bottom 42a of the recess 42. Furthermore, a portion of the support member 110 may be a projection protruding from the bottom 24a, covered by the internal antenna portion 90, but not electrically connected to the external antenna portion 50, and having only the function of supporting the transducer 200. Similarly, a portion of the support member 170 may be a projection protruding from the bottom 42a, covered by the internal antenna portion 180, but not electrically connected to the external antenna portion 120, and having only the function of supporting the transducer 200. In addition, the detection element 100 includes an external antenna portion 50 and an internal antenna portion 90 electrically connected thereto, and an external antenna portion 120 and an internal antenna portion 180 electrically connected thereto, but it may also be configured to include only one of the external antenna portions and the internal antenna portion electrically connected thereto. In this case, one of the external antenna portions and the internal antenna portion electrically connected thereto will be responsible for the transmission and reception functions.

[0027] Furthermore, in the space 11, a projection 112 is formed on the side wall portion 111, which is located in the planar direction of the transducer 200 and connects the bottom portion 24a and the bottom portion 42a, projecting toward the transducer 200. The projection 112 is, for example, semi-circular in shape. Here, two projections 112 are provided on each side wall portion 111. These projections restrict the movement of the transducer 200 in the planar direction and prevent the transducer 200 from directly contacting the side wall portion 111. The side wall portion 111 and the projection 112 are composed of the side wall portions of the recess 24 of the glass substrate 20 and the recess 42 of the glass substrate 40. The side wall portion 111 corresponds to the wall portion of this disclosure.

[0028] The housing 10 of the detection element 100 is provided with a flow path 12 and a flow path 13 that communicate with the space 11. The flow path 12 communicates with the space 11 at one end and with the recessed end 24 of the opening 22 at the other end. The flow path 13 communicates with the space 11 at one end and with the recessed end 24 of the opening 23 at the other end. As shown by the arrows in Figure 3, fluid introduced into the detection element 100 from the opening 22 flows through the flow path 12 and over the surface of the vibrator 200 located in the space 11. The fluid that flows out of the space 11 is then discharged from the opening 23 through the flow path 13. The fluid may be a liquid or a gas. It is also possible to introduce the fluid from the opening 23 and discharge it from the opening 22. The flow paths 12 and 13 correspond to the flow paths of this disclosure.

[0029] Figures 5 and 6 are process diagrams showing the manufacturing method of the detection element 100. In Figures 5 and 6, a cross-section with five support members 170 and 110 is used for explanation, but this is a configuration for explaining the manufacturing method and does not correspond to a specific cross-section of the detection element 100 shown in Figure 1.

[0030] First, as shown in Figure 5(A), a glass substrate 40 is fabricated with the column portion 130 of the support member 170 passing through it (Step 1). The column portion 130 of the support member 170 is made of tungsten (W). The diameter of the column portion 130 is, for example, 0.1 mm. In the glass substrate 40, the column portion 130 and the glass are in close contact, and no fluid leaks from between the column portion 130 and the glass.

[0031] Next, as shown in Figure 5(B), a recess 42 is formed on the upper surface of the glass substrate 40 by molding or etching (Step 2).

[0032] Next, as shown in Figure 5(C), a conductive film 140 is formed on the upper end face 43 of the glass substrate 40 and the bottom 42a of the recess 42 of the glass substrate 40 (step 3). The conductive film 140 is formed, for example, by coating chromium (Cr), titanium (Ti), or the like, which have a coefficient of thermal expansion compatible with that of the glass.

[0033] Next, as shown in Figure 5(D), the external antenna portion 120 is formed on the surface 41 of the glass substrate 40 (step 4). Here, for example, the external antenna portion 120 is formed by laminating an adhesion layer of titanium (Ti) or chromium (Cr) with an electrode layer of gold (Au) or platinum (Pt).

[0034] Next, as shown in Figure 5(E), the conductive film 140 formed in step 3 is etched (step 5). Etching removes the conductive film 140 except for the area covering the exposed ends of the columnar portion 130.

[0035] Next, as shown in Figure 5(F), the head portion 150 is fabricated on the conductive film 140 by plating (step 6). The head portion 150 can be formed, for example, by laminating nickel or gold onto copper using plating with the conductive film 140.

[0036] Next, as shown in Figure 6(A), the internal antenna portion 180 is formed on the head portion 150 and the bottom portion 42a of the recess 42, and the portion other than the predetermined area is removed by etching (step 7). The internal antenna portion 180 is formed by laminating, for example, a titanium (Ti) or chromium (Cr) adhesion layer and a gold (Au) or platinum (Pt) electrode layer. Here, the predetermined area on which the internal antenna portion 180 is formed covers the entire transducer 200, and preferably has an area larger than the area of ​​the transducer 200.

[0037] Next, as shown in Figure 6(B), the portion of the deposited external antenna portion 120 other than the predetermined area is removed by etching (step 8). Here, the area in which the external antenna portion 120 is formed is the area corresponding to the internal antenna portion 180 formed across the glass substrate 40, preferably the area including it.

[0038] Next, as shown in Figure 6(C), the transducer 200 is mounted in the recess 42 of the glass substrate 40 (step 9). Here, the transducer 200 is supported by the support member 170 via the internal antenna portion 180. A suitable method can be used for mounting the transducer 200.

[0039] Next, as shown in Figure 6(D), a structure 100A is prepared separately from the structure 100B manufactured in steps 1 to 8 (step 10). In structure 100A, a conductive film 70, a head portion 80, an internal antenna portion 90, and an external antenna portion 50 are created on the glass substrate 20 manufactured in step 1 by steps 2 to 8, and openings 22 and 23 that penetrate the glass substrate in the thickness direction are created by machining.

[0040] Next, as shown in Figure 6(E), the end face 25 on the recess 24 side of structure 100A and the end face 43 on the side where the resonator 200 is mounted of structure 100B are joined (step 11). As a joining method in step 11, for example, laser joining, room temperature joining, joining via metal, joining using electrostatic attraction, hydrogen joining, etc., can be used. This makes it possible to join the glass and package the detection element in a low-temperature environment that does not damage the resonator 200 (including the sensitive film formed on the resonator 200, etc.) by heating, rather than in a high-temperature environment of about 300°C as in the conventional method, thus enabling the manufacture of a highly sensitive detection element 100 with a good yield. Laser joining is a method in which the glass is first optically contacted and then locally melted on the order of microns using a femtosecond laser. Room temperature joining is a method in which the surface roughness of the glass surface is finished to submicron, and then plasma activated in an atmosphere of argon, oxygen, water vapor, etc., and joined at room temperature by optical contact. Metal-mediated joining methods include using low-melting-point solder, such as tin or silver paste, which melts at temperatures below 300°C. Furthermore, electrostatic bonding methods include anodic bonding. Hydrogen bonding involves pre-polishing the glass to a mirror finish, performing optical contact, and then heating in a hydrogen atmosphere to achieve the desired joint. End face 25 corresponds to the first joint in this disclosure. End face 32 corresponds to the second joint in this disclosure.

[0041] In the process diagrams of Figures 5 and 6, the transducer 200 is mounted on the glass substrate 40 side, but the transducer 200 may also be mounted on the glass substrate 20 side. Furthermore, the position of the bonding surface 14 in the thickness direction by process 12 is not limited to that shown in Figure 6(E). Depending on the depth of the recess 24 in the glass substrate 20 (including cases where the recess 24 is not provided) and the depth of the recess 42 in the glass substrate 40 (including cases where the recess 42 is not provided) in the thickness direction of the detection element 100, the position of the bonding surface 14 in the thickness direction may differ. As shown in Figure 6(E), in addition to the configuration in which the height of structure 100A and the height of structure 100B are almost symmetrical and the bonding surface 14 is located almost in the center in the thickness direction, it is also possible to have a configuration in which the height of structure 100A and the height of structure 100B are asymmetrical and the bonding surface 14 is located in a position biased to the upper or lower part of the thickness direction.

[0042] Figure 7 shows a schematic configuration of a detection system 300 including a detection element 100. The detection system 300 includes a transceiver 310, a transmitting antenna 321, a receiving antenna 322, cables 331 and 332, an analysis device 340, a detection element 100, a receiving antenna 351, a transmitting antenna 352, connecting lines 361 and 362. The analysis device 340 is a computer that implements analysis software 341 which analyzes electromagnetic waves transmitted and received by the transceiver 310 and detects an object to be detected by the detection element 100, and may be provided integrally with the transceiver 310. Here, the detection system 300 corresponds to the detection system of this disclosure. Also, the transceiver 310 and the analysis device 340 correspond to the transceiver and analysis device and analysis device of this disclosure, respectively.

[0043] A transmission / reception device 310 is connected to a transmission antenna 321 via a cable 331 and to a reception antenna 322 via a cable 332. The transmission antenna 321 and the reception antenna 322 are not limited to independent antennas for transmission and reception, and may be configured as a transmission / reception antenna. For example, a Yagi antenna can be used. Further, a reception antenna 351 is connected to an external antenna unit 50 of the detection element 100 via a connection line 361, and a transmission antenna 352 is connected to an external antenna unit 120 via a connection line 362. The reception antenna 351 and the transmission antenna 352 are not limited to independent antennas for transmission and reception, and may be configured as a transmission / reception antenna. For example, a mobile antenna can be used. When only one of the external antenna unit 50 or the external antenna unit 120 is provided to perform the transmission / reception function, the reception antenna 351 and the transmission antenna 352 may be configured to be connected to one of these external antenna units, or the transmission / reception antenna may be connected to one of these external antenna units.

[0044] FIGS. 8 and 9 are timing charts for explaining a method of detecting a detection target using the detection element 100 in the detection system 300. FIG. 8 is a timing chart of an input voltage Vin and a reception signal R. FIG. 9 is a timing chart of a resonance frequency.

[0045] The transmission / reception device 310 transmits a predetermined electromagnetic wave as a transmission signal from the transmission antenna 321 toward the detection element 100. Hereinafter, the external antenna unit 50, the support member 110, and the internal antenna unit 90 are used for reception, and the external antenna unit 120, the support member 170, and the internal antenna unit 180 are used for transmission. However, a configuration in which the transmission / reception relationship is reversed is also possible. The received vibration waveform applies an input voltage Vin to the external antenna unit 50, the support member 110, and the internal antenna unit 90. The transmission / reception device 310 applies an input voltage Vin composed of a vibration waveform to the external antenna unit 50, the support member 110, and the internal antenna unit 90 from timing t1 to t2. Then, the transmission / reception device 310 stops applying the input voltage Vin to the external antenna unit 50, the support member 110, and the internal antenna unit 90 after timing t2.

[0046] The internal antenna unit 90 applies an oscillating electric field generated based on the input voltage Vin to the vibrator 200 from timing t1 to timing t2. When the oscillating electric field is applied, the vibrator 200 resonates due to the inverse piezoelectric effect, and a potential distribution occurs on the surface.

[0047] The internal antenna unit 180 receives the potential distribution generated on the surface of the vibrator 200 as a received signal R having an oscillating waveform. At this time, if the detection target is not attached to the vibrator 200, the internal antenna unit 180 receives a received signal R0 having an oscillating waveform, and if the detection target is attached to the vibrator 200, the internal antenna unit 180 receives a received signal R1 having an oscillating waveform. The internal antenna unit 180 transmits the received received signals R0, R1 to the transceiver via the support member 170, the external antenna unit 120, and the transmission antenna 352.

[0048] When the receiving antenna 322 connected to the transceiver 310 receives the received signal R0 from the transmission antenna 352, the analysis device 340 connected to the transceiver 310 detects the resonance frequency f0 of the received received signal R0. Also, when the receiving antenna 322 connected to the transceiver 310 receives the received signal R1 from the transmission antenna 352, the analysis device 340 connected to the transceiver 310 detects the resonance frequency f1 (<f0) of the received received signal R1. The analysis device 340 detects the change amount Δf = f0 - f1 of the resonance frequency, and detects that the detection target has adhered to the vibrator 200. Here, the resonance frequency corresponds to a predetermined index of the present disclosure, and the change amount Δf of the resonance frequency corresponds to the temporal change of the predetermined index of the present disclosure.

[0049] When the detection target adheres to the vibrator 200, the mass of the vibrator 200 increases, so the resonance frequency f1 of the vibrator 200 decreases compared to the case where the detection target does not adhere to the vibrator 200.

[0050] Therefore, after the input voltage Vin is applied to the receiving antenna 351, the analysis device 340 receives a received signal R from the transmitting antenna 352. When the object to be detected is not attached to the transducer 200, it detects the resonant frequency f0 from the received signal R. When the object to be detected attaches to the transducer 200, it detects the resonant frequency which gradually changes to the resonant frequency f1, as shown in Figure 6. The analysis device 340 detects the change in resonant frequency Δf = f0 - f1 and detects that the object to be detected has attached to the transducer 200. Such changes in resonant frequency may be continuously monitored using the transmitting / receiving device 310 and the analysis device 340, or they may be detected sporadically, such as in a LOT inspection.

[0051] If the resonant frequency of the oscillator 200 is f and the thickness of the oscillator 200 is d, then the change in the resonant frequency of the oscillator 200, Δf, is expressed by equation (1) (where k is the proportionality constant). Δf = k / d ２ ... (1) Thus, the change in resonant frequency f, Δf, increases as the transducer 200 becomes thinner, and by making the transducer 200 thinner, high sensitivity is achieved.

[0052] Furthermore, by making the transducer 200 thinner, its sensitivity is increased, and it becomes possible to transmit and receive signals using high-frequency electromagnetic waves. While the frequency of conventional detection elements was around 30 MHz, the transducer 200 according to this embodiment can transmit and receive signals using electromagnetic waves with frequencies exceeding 100 MHz. As a result, the detection element 100 according to this embodiment can perform detection wirelessly and even without power supply.

[0053] Furthermore, the detection element 100 is positioned to contact at least one of the internal antenna portion 90 on the support member 110 and the internal antenna portion 180 on the support member 170. Therefore, when an electromagnetic field is applied by the internal antenna portion 90, the transducer 200 can vibrate freely. In addition, since the internal antenna portion 90 and the internal antenna portion 180 are in contact with or very close to the transducer 200, the output of electromagnetic waves for exciting the transducer 200 can be reduced, and even if the electric field generated from the transducer 200 is weak, the object to be detected can be easily detected.

[0054] Furthermore, since the detection element 100 is wireless and does not require power supply, it can be installed in locations or parts that are difficult for people to access, and can be used for continuous detection.

[0055] The detection element 100 can be used as a biosensor for drug discovery and early disease detection. In this case, for example, a receptor protein having high affinity for the target protein is immobilized on the surface of the vibrator 200. By flowing a sample such as blood through the openings 22 and 23 onto the surface of the vibrator 200 located in the space 11, the substance to be detected is captured by the receptor protein. As a result, the mass of the vibrator 200 increases, and the resonant frequency of the vibrator 200 changes. By detecting this change in the resonant frequency of the vibrator 200, the concentration of the substance to be detected can be detected with high sensitivity. Similarly, by flowing exhaled breath through the openings 22 and 23 onto the surface of the vibrator 200 located in the space 11, specific molecules caused by disease can also be detected with high sensitivity.

[0056] Furthermore, the detection element 100 can be used as a gas sensor. In this case, for example, a Pd thin film is formed on the surface of the transducer 200 as a sensitive film. By allowing hydrogen gas to flow into the space 11 through the openings 22 and 23, the hydrogen gas is adsorbed onto the sensitive film on the surface of the transducer 200 placed in the space 11, and the shape of the transducer 200 changes. This change in the shape of the transducer 200 also changes the resonant frequency of the transducer 200, so the concentration of hydrogen gas can be detected with high sensitivity by measuring the amount of change Δf in the resonant frequency.

[0057] <Example 2> Figure 10 shows a schematic configuration of the detection system 500 according to Example 2. Components common to the detection system 300 according to Example 1 are referred to with the same reference numerals and detailed explanations are omitted.

[0058] In the detection system 500, the transmitting / receiving device 310 and the external antenna section 50 and external antenna section 120 of the detection element 100 are directly connected by cables 411 and 412, respectively. In this way, in the detection system 500, the transmitting / receiving device 310 and the detection element 100 are connected by wires, and signals are transmitted and received. In the detection system 500, if only one of the external antenna section 50 or the external antenna section 120 is provided and is responsible for transmitting and receiving functions, then this one external antenna section is connected to the transmitting / receiving device 310 by a cable.

[0059] The detection method of the detection system 500 is the same as that of the detection system 300, except that the signals are transmitted and received via cables 411 and 412.

[0060] <Modification> In the detection system 300 according to Example 1 and the detection system 500 according to Example 2, a passive detection element 100 is used. However, for targets that cannot be detected by such a detection element 100, other existing detection elements (for example, passive or active sensors such as RFID (Radio Frequency Identification) or NFC (Near Field Communication)) may be used in combination.

[0061] <Application Examples> Detection systems 300 and 500 use the detection element 100 described in Example 1. As mentioned above, the detection element 100 can be used as a biosensor or gas sensor. The detection elements constituting detection systems 300 and 500 are not limited to these sensors, and various sensors exemplified below can be applied.

[0062] For example, applicable detection elements can be broadly classified as follows depending on what is being detected: (1) Optical sensors: Detect infrared rays, light, illuminance, proximity, distance, color, radiation, images, lasers, etc. (2) Mechanical sensors: Detect pressure, acceleration, angular velocity, rotation, shock, displacement, strain, vibration, tilt, gyroscope, 3D motion, sound, etc. (3) Temperature and humidity sensors: Detect temperature, humidity, etc. (4) Magnetic / current sensors: Detect magnetism, electric current, static electricity, etc. (5) Chemical / biosensors: Detect gases, glucose, blood glucose levels, ions, etc. (6) Biological sensors: Detect taste, smell, brain waves, pulse waves, etc. (7) Other sensors: Detect ultrasound, flow rate, position, etc. Of the above sensors, optical sensors, pressure sensors, sound sensors (microphones), etc. are classified as physical quantity sensors, while gas sensors, odor sensors, taste sensors, etc. are classified as chemical quantity sensors.

[0063] Furthermore, the detection elements described above can be used for the following applications: for example, temperature / humidity detection, detection of the amount of target substance in an antibody, detection of specific gases, detection of specific odors, detection of dust / powder / mist, detection of liquid leaks, water level detection, detection of solid vibrations, detection of solid stress, detection of the working range or movement path of people such as workers or robots, and maintenance of specific machinery / equipment.

[0064] Furthermore, the aforementioned detection elements can be used in the following fields: for example, manufacturing equipment, measurement / analysis equipment, medical equipment, IoT devices, mobile devices, logistics / inventory management (ID tags), bio, biological systems, factories, plants, tanks, painting, cleaning, buildings / construction, sites, infrastructure, roads / surfaces, railways, overpasses, bridges, dams, tunnels, rivers, slopes, embankments, forests / farms / horticulture, power generation (thermal, wind, hydro, tidal, nuclear), switchboards, defense, space, and other fields.

[0065] 12, 13: Flow path 22, 23: Opening 90, 150: Internal antenna section 50, 120: External antenna section 100: Detection element 110, 170: Support member 200: Transducer

Claims

1. A detection element comprising: a housing made of glass, including a first surface and a second surface facing each other and forming a space; an internal antenna portion disposed on at least one of the first surface and the second surface; an external antenna portion disposed on the opposite side of the housing from the surface on which the internal antenna portion is disposed, and electrically connected to the internal antenna portion; a first support member protruding from the first surface toward the second surface; a second support member protruding from the second surface toward the first surface; and a piezoelectric vibrator vibrating in the space, near or in contact with the internal antenna portion by at least one of the first support member and the second support member, wherein the housing has a plurality of openings that open to the outside of the housing and communicate with the space; and a flow path that allows fluid to communicate between the space and the plurality of openings.

2. The detection element according to claim 1, wherein the housing comprises a first component made of glass and including the first surface, and a second component made of glass and including the second surface, which are laminated together.

3. A detection system comprising: a detection element according to claim 1 or 2; a transmitting and receiving device that transmits a transmission signal to the detection element and receives a reception signal from the detection element by wire or wireless means; and an analysis device that analyzes the reception signal and detects a temporal change in a predetermined indicator.

4. A method for manufacturing a detection element, comprising a housing having a space inside that includes a first surface and a second surface facing each other with respect to a piezoelectric vibrator in which a piezoelectric vibrator is arranged to be vibrable, the method comprising: a step of manufacturing a first structure of the detection element, which includes a first component made of glass of the housing including the first surface; a step of manufacturing a second structure of the detection element, which includes a second component made of glass of the housing including the second surface; a step of arranging the piezoelectric vibrator to be vibrable in either the first structure or the second structure; and a step of joining a first joint made of glass of the first structure and a second joint made of glass of the second structure to form the space.

5. The method for manufacturing a detection element according to claim 4, wherein the step of forming the space is to join the first joint and the second joint in a low-temperature environment.

6. The method for manufacturing a detection element according to claim 5, wherein the step of forming the space is to join the other of the first structure and the second structure to one of the first structure and the second structure that holds the piezoelectric vibrator.

7. The method for manufacturing a detection element according to claim 6, wherein the step of forming the space is a step of joining the first joint and the second joint by laser bonding.

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