Sensor and detection device

Abstract

To improve sensing sensitivity by enhancing the effect of agitating a specimen through heating, a fluid sensor according to the present invention comprises: a piezoelectric layer having a main surface; a substrate including the piezoelectric layer; a heater provided on the main surface; a sensitive film which is provided on the main surface, has a surface on the opposite side from the piezoelectric layer, and reacts with a target substance; bottom and top electrodes which are stacked with the piezoelectric layer sandwiched in between and which are for propagating an elastic wave within the piezoelectric layer in at least a region where the piezoelectric layer and the surface overlap; a first channel which is provided on the main surface, which has a first inner wall, and in which, when a liquid flows, the first inner wall, the region, and an inner wall including the surface of the heater act as a channel for the liquid; and a second channel which is provided on the main surface in communication with the first channel, which has a second inner wall, and in which, when a liquid flows, the second inner wall and an inner wall including the surface act as a channel for the liquid, the second channel being located downstream of the first channel in the direction of liquid flow.

Description

Sensors and Detection Devices

[0001] The present invention relates to sensors and detection devices.

[0002] Conventionally, biosensors that detect antigens such as proteins using antibodies as receptors are known. It is known that stirring a liquid sample containing antigens mixes the sample and promotes an antigen-antibody reaction. It is also known that raising the temperature of the sample to a predetermined temperature promotes thermal molecular motion, thereby promoting the antibody-antigen reaction.

[0003] The sensor described in Patent Document 1 is configured so that a liquid sample is held in contact with a detection unit of the sensor, and a target substance can be detected by dropping the sample into a liquid reservoir. The sensor described in Patent Document 2 has a flow path provided on a piezoelectric body, a sensor inside the flow path, and a heater and a temperature sensor around the flow path. The heater is controlled based on the output of the temperature sensor to keep the temperature of the sample uniform and promote the antibody-antigen reaction.

[0004] Japanese Patent No. 3952083 U.S. Patent No. 11467126

[0005] However, with the technology disclosed in Patent Document 1, when a sample is dropped and reaches a steady state, the antigen may be present in a biased position within the sample, potentially resulting in insufficient antigen-antibody reaction. Furthermore, with the technology disclosed in Patent Document 2, the heater is spaced apart from the flow path, so heat from the heater is transferred to the sample in the flow path via the air and the walls of the flow path. This can reduce the heat transfer coefficient due to the air and walls, potentially slowing the generation of thermal convection or making it difficult for thermal convection to occur. The present invention has been developed in consideration of the above-mentioned problems, and aims to provide a sensor and detection device that can enhance the sample agitation effect caused by heating and improve sensing sensitivity.

[0006] The present invention provides a sensor comprising: a piezoelectric body having a main surface; a substrate including the piezoelectric body; a heater provided on the main surface; a sensitive membrane provided on the main surface, having a surface opposite to the piezoelectric body side, and reacting with a target substance; a pair of electrodes provided on the main surface, for propagating elastic waves in at least a region in the piezoelectric body where the main surface and the surface overlap; a first flow path provided on the main surface, having a first inner wall, wherein when a liquid flows, the inner wall including the first inner wall, the region, and the surface of the heater becomes a flow path for the liquid; and a second flow path provided on the main surface and communicating with the first flow path, having a second inner wall, wherein when a liquid flows, the inner wall including the second inner wall and the surface becomes a flow path for the liquid, and which is downstream of the flow of liquid from the first flow path.

[0007] In the above configuration, the heater may have a plurality of linear heat generating portions extending in the width direction of the first flow path and arranged in parallel at predetermined intervals along a length direction that is orthogonal to the width and height directions. In the above configuration, the heater may have a plurality of linear heat generating portions extending in an oblique direction intersecting a length direction that is orthogonal to the width and height directions of the first flow path and arranged in parallel at predetermined intervals along a direction orthogonal to the oblique direction. In the above configuration, a protective film may be formed along an uneven shape formed by the heat generating portions and a portion of the main surface. In the above configuration, the width of the first flow path may be configured to be larger than the width of the second flow path. In the above configuration, the heater may have a temperature sensor provided in the first flow path that detects the temperature of the analyte in the first flow path.

[0008] In the above configuration, the pair of electrodes may be a pair of comb-shaped electrodes provided below the sensitive membrane on the piezoelectric body, and the sensor unit may be provided in the second region on the main surface and include reflectors provided at positions facing each other across the pair of comb-shaped electrodes in the propagation direction of the elastic waves. In the above configuration, the sensitive membrane may be formed along the electrode shapes of the comb-shaped electrodes. In the above configuration, the pair of electrodes may be a pair of first comb-shaped electrodes for transmitting the elastic waves and a pair of second comb-shaped electrodes for receiving the elastic waves, which face each other across the sensitive membrane in a length direction that is perpendicular to the width and height directions of the second flow path. In the above configuration, the sensitive membrane may be formed along the electrode shapes of the first comb-shaped electrodes and the second comb-shaped electrodes. In the above configuration, the pair of electrodes may be a first electrode and a second electrode stacked with the piezoelectric body sandwiched therebetween, and the sensitive membrane may be provided at a position where its surface overlaps with the first electrode and the second electrode in the stacking direction.

[0009] The present invention provides a detection device comprising: a power supply that supplies power to the heater of the sensor of any of the above configurations; a transmitter that transmits a high-frequency signal to the pair of electrodes of the sensor to generate the elastic waves; a measuring instrument that measures information about the elastic waves propagated to the portion where the piezoelectric body and the surface overlap; and a detector that detects the target substance based on the information measured by the measuring instrument. In the above configurations, the sensor may have a temperature sensor that detects the temperature of the analyte in the first flow path, and may further comprise a temperature controller that controls the temperature of the analyte in the first flow path based on the temperature measured by the temperature sensor.

[0010] According to the present invention, the effect of stirring the sample by heating can be enhanced, thereby improving sensing sensitivity.

[0011] 1 is a plan view showing a schematic configuration of a fluid sensor according to a first embodiment. It is a cross-sectional view of the cross section taken along line A-A' in FIG. 1 as viewed from the -Y direction, which will be described later. It is a cross-sectional view showing a detailed configuration of the resonant element in FIG. 2. It is a block diagram showing an example of a configuration of a detection device. It is a cross-sectional view showing an example of the flow state of a sample in a first flow path when a heater is operated. (a) and (b) are cross-sectional views showing an example of the distribution state of a target substance in a second flow path when a heating operation is performed and when it is not performed. (a) to (e) are diagrams showing an example of the wiring configuration of a heating wire, and (f) and (g) are schematic views showing an example of the shape of a flow path and the flow of a sample in each first flow path. It is a plan view showing a schematic configuration of a fluid sensor according to a second embodiment. It is a cross-sectional view taken along line B-B' in FIG. 8. It is a partial cross-sectional view of the fluid sensor according to the second embodiment. (a) and (b) are cross-sectional views showing an example of the distribution state of a target substance in a second flow path when a heating operation is performed and when it is not performed. It is a plan view showing a schematic configuration of a fluid sensor according to a third embodiment. It is a cross-sectional view taken along line C-C' in FIG. 12. It is a plan view showing a schematic configuration of a fluid sensor according to a modified example. Fig. 15 is a cross-sectional view taken along the line DD' of Fig. 14. Fig. 16 is a plan view showing a schematic configuration of a fluid sensor having two flow paths and a sensor portion according to a modified example.

[0012] Hereinafter, the embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. Note that the embodiments described below are examples of means for realizing the present invention, and should be appropriately modified or changed depending on the configuration of the device to which the present invention is applied and various conditions, and the present invention is not limited to the following embodiments.

[0013] Furthermore, in the following drawings, identical or similar parts are designated by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the vertical and horizontal dimensions and scales of components or parts may differ from those of the actual components. Therefore, specific dimensions and scales should be determined with reference to the following explanation. Naturally, parts in the drawings may have different dimensional relationships and ratios. [First Embodiment] First, a first embodiment of the present invention will be described. FIGS. 1 to 7 are diagrams illustrating the first embodiment. [Configuration] FIG. 1 is a plan view showing the schematic configuration of a fluid sensor 1 according to the first embodiment, and FIG. 2 is a cross-sectional view of the cross section taken along line A-A' in FIG. 1, viewed from the -Y direction (described later). FIG. 3 is a cross-sectional view showing the detailed configuration of the resonant element 16a in FIG. 2. As shown in FIGS. 1 to 3, the fluid sensor 1 includes a substrate 12, a flow path 14, a heater 20, a temperature sensor 22, and a sensor unit 16. The substrate 12 will be described as a thick rectangular substrate, with the height direction of the substrate 12 being the Z direction, the longitudinal direction being the X direction, and the direction perpendicular to the Z direction and the X direction being the Y direction. The same applies to Figures 4 and onwards.

[0014] The substrate 12 has a principal surface 12a. A portion of the principal surface 12a is a first region 12b, and a portion of the principal surface 12a that is different from the first region 12b is a second region 12c. The first region 12b and the second region 12c are shown as regions surrounded by dashed lines in FIG. 1. The second region 12c is disposed adjacent to the first region 12b on the +X direction side. The planar shape of the substrate 12 is a rectangle with its long side in the X direction and its short side in the Y direction. Here, the rectangular shape does not have to be a geometric rectangle, and the opposing sides may deviate from parallel by approximately 10°. The corners may also be rounded. The same applies to rectangular shapes described below. As will be described in detail below, the substrate 12 is a substrate having a piezoelectric body, which is a structure made of a piezoelectric material.

[0015] The substrate 12 may be a piezoelectric substrate containing this piezoelectric material. In this case, an IDT (Inter-Digital Transducer) electrode is formed on the main surface 12a of the piezoelectric substrate. The substrate 12 includes a piezoelectric layer containing this piezoelectric material and may have the following configuration: The substrate 12 may be configured such that the piezoelectric layer is provided on a support substrate via an insulating layer such as silicon dioxide (SiO2). In this case, an IDT electrode is formed on the main surface 12a of the piezoelectric layer. The substrate 12 may include an insulating layer such as silicon dioxide provided on the support substrate, multiple layers of metal or the like provided on part of this insulating layer to form an acoustic reflection film, and a piezoelectric layer sandwiched between a pair of electrodes provided on the acoustic reflection film. The substrate 12 may also include a void provided on the surface of the support substrate, and a piezoelectric layer sandwiched between a pair of electrodes provided at a position corresponding to the void.

[0016] The flow channel 14 includes multiple side walls and a ceiling wall, and the inner surfaces of these multiple side walls and the ceiling wall form the inner wall. These inner walls, together with, for example, the inner wall of a portion of the main surface 12a of the substrate 12, form a flow channel for flowing the analyte. These two inner walls are referred to as the inner wall portion. The portion of the main surface 12a of the substrate 12 is referred to as the bottom surface. The heater 20, the temperature sensor 22, and the sensor unit 16 are provided on the bottom surface. Specifically, the heating wire 21 of the heater 20, the metal wire 23 of the temperature sensor 22, and the sensitive film 16b are provided on the bottom surface. A space is defined by the inner wall portion of the flow channel 14, the inner wall portion including the portion of the main surface 12a, the area where the heater 20 and the temperature sensor 22 are provided, and the surfaces of the heater 20, the temperature sensor 22, and the sensor unit 16.

[0017] Hereinafter, the inner walls of the side walls and ceiling wall forming the first flow path 14a will be referred to as the "first inner walls," and the inner walls of the side walls and ceiling wall forming the second flow path 14b will be referred to as the "second inner walls." The flow path 14 includes a first flow path 14a disposed in the first region 12b and a second flow path 14b disposed in the second region 12c, communicating with the first flow path 14a. The flow path formed by the first inner wall and bottom surface of the first flow path 14a is upstream of the analyte flow, and the flow path formed by the second inner wall and bottom surface of the second flow path 14b is downstream of the analyte flow. For example, the direction in which the flow path 14 extends is the longitudinal direction of the substrate 12. As shown in FIG. 1 , the width of the first flow path 14a is configured to be larger than the width of the second flow path 14b. One end of the second flow path 14b in the -X direction extends toward the first flow path 14a and communicates with the first flow path 14a, and the other end in the +X direction extends to the opposite side from the first flow path 14a.

[0018] As shown in FIG. 2 , the flow channel 14 is fixed to the substrate 12 by adhesively fixing the lower ends of its side walls to the main surface 12a of the substrate 12 via an adhesive member 70. Alternatively, the flow channel 14 may be provided directly on the substrate 12 without the adhesive member 70. The flow channel 14 may be made of, for example, a resin material such as PDMS (dimethylpolysiloxane) or glass. The adhesive member 70 may be made of, for example, adhesive tape or a thermosetting resin such as PDMS. As an example, the adhesive member 70 may be made of adhesive tape. Using adhesive tape allows the height of the adhesive portion to be uniform. A reservoir 26 is connected to the first flow channel 14a via a joint 28a and a tube 24a, and a reservoir 32 is connected to the second flow channel 14b via a joint 28b and a tube 24b. The reservoirs 26 and 32 are, for example, tanks for storing a liquid sample. The reservoir 32 contains a pump, which can be controlled to allow a constant flow rate of the sample to flow through the flow path 14 .

[0019] The joint 28a is cylindrical and is provided on the ceiling wall of the −X-direction end of the first flow path 14a. The joint 28a is in communication with the interior of the first flow path 14a, and one end of the tube 24a is connected to the +Z-direction end of the joint 28a. The other end of the tube 24a is connected to the liquid reservoir 26.

[0020] The joint 28b is cylindrical and is provided on the ceiling wall of the +X-direction end of the second flow path 14b. The joint 28b communicates with the internal space of the second flow path 14b, and one end of the tube 24b is connected to the +Z-direction end of the joint 28b. The other end of the tube 24b is connected to the liquid reservoir 32.

[0021] With this configuration, the negative pressure generated in reservoir 32 causes the analyte stored in reservoir 26 to be supplied into first flow path 14a via tube 24a and joint 28a. Furthermore, the analyte in second flow path 14b is discharged into reservoir 32 via joint 28b and tube 24b. A heater 20 and a temperature sensor 22 are provided in first region 12b on main surface 12a. Heater 20 includes a heating wire 21 that is wired in a serpentine manner in first region 12b on main surface 12a, and a first protective film 18 that covers heating wire 21.

[0022] The heating wire 21, excluding both ends for applying voltage, is disposed within the first flow path 14a and is wired in a serpentine pattern in the X direction, which is the length direction of the first flow path 14a. That is, the serpentine wiring of the heating wire 21 has multiple long portions 21a extending in the Y direction, which is the width direction of the first flow path 14a, and multiple short portions 21b extending in the X direction of the first flow path 14a. The heating wire 21 can be made of a material that generates heat upon application of a voltage. For example, it can be made of platinum (Pt), gold (Au), tungsten (W), aluminum (Al), titanium (Ti), or the like. The thickness of the heating wire 21 can be, for example, 10 nm to 1 μm, the width can be, for example, 10 to 100 μm, and the spacing between adjacent long portions 21a can be, for example, 10 to 1000 μm.

[0023] The temperature sensor 22 includes a metal wire 23 that is disposed on the main surface 12a at a position facing the heater 20 in the Y direction and that is wired in a serpentine manner, and a first protective film 18 that covers the metal wire 23. The temperature sensor 22 detects a change in resistance value as a temperature change when a voltage is applied to a resistance temperature detector (RTD) that includes the metal wire 23.

[0024] The metal wire 23, except for both ends for applying voltage, is disposed within the first flow path 14a and is wired in a serpentine pattern in the X direction. That is, the serpentine metal wire 23 has multiple long portions 23a extending in the Y direction and multiple short portions 23b extending in the X direction. The short portions 23b are configured to have the same length as the short portions 21b of the heating wire 21, and the metal wire 23 is arranged so that the short portions 23b are parallel to and face the short portions 21b of the heating wire 21 in the Y direction. The metal wire 23 can be made of the same material as the heating wire 21 of the heater 20, as well as nickel (Ni), copper (Cu), or the like. The thickness, width, and spacing of the metal wire 23 can be configured to be the same as the thickness, width, and spacing of the heating wire 21. The first protective film 18 is a film that protects the heating wire 21 and the metal wire 23 in the first flow path 14a from moisture and the like.

[0025] The first protective film 18 is configured to cover the heating wire 21 and the metal wire 23 along the uneven shape formed by the meandering heating wire 21 and a portion of the main surface 12a, and the uneven shape formed by the metal wire 23 and a portion of the main surface 12a. That is, the first protective film 18 has an uneven shape that follows the uneven shape formed by the heating wire 21, the metal wire 23, and a portion of the main surface 12a. The surface of the first protective film 18 also forms a portion of the inner wall of the first flow path 14a. The first protective film 18 can be composed of an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon nitride oxide film.

[0026] 1 to 3, the sensor unit 16 includes a resonant element 16a and a sensitive film 16b. The resonant element 16a is a resonant sensor element that uses bulk acoustic waves, and is configured to include a part of the substrate 12. Specifically, as shown in FIG. 3, the substrate 12 is configured such that an acoustic reflection film 40, a lower electrode 42, a piezoelectric layer 44, and an upper electrode 46 are stacked on a support substrate 39. In the example shown in FIG. 3, the resonant element 16a is configured from the acoustic reflection film 40, the lower electrode 42, the piezoelectric layer 44, and the upper electrode 46 that constitute the substrate 12.

[0027] The acoustic reflection film 40 is constructed by alternating layers of low- and high-acoustic-impedance films. By setting the thickness of each film to approximately ¼ of the wavelength of the acoustic wave, the acoustic wave is reflected by the acoustic reflection film 40. Here, the bottom layer of the acoustic reflection film 40 is a high-impedance film, and the top layer is a low-impedance film. The high-impedance film can be composed of an oxide layer containing one or more elements selected from the group consisting of niobium (Nb), tantalum (Ta), tungsten, and molybdenum (Mo). The low-impedance film can be composed of an oxide layer containing a low-impedance oxide element, such as silicon dioxide. The planar shapes of the lower electrode 42 and the upper electrode 46 are rectangular, with the longer side extending in the X direction. The lower electrode 42 and the upper electrode 46 correspond to the first electrode and the second electrode, respectively. The lower electrode 42 has a predetermined width and extends continuously in the +X direction from the end of the piezoelectric layer 44 on the −X direction side toward the end on the +X direction side. The predetermined width is, for example, the same width as the piezoelectric layer 44 .

[0028] The upper electrode 46 has a predetermined width and extends continuously in the −X direction from the end of the piezoelectric layer 44 on the +X direction side to the end on the −X direction side. The predetermined width is, for example, the same width as the piezoelectric layer 44. The lower electrode 42 is connected to the wiring 30a, and the upper electrode 46 is connected to the wiring 30b. The region where the piezoelectric layer 44, the lower electrode 42, and the upper electrode 46 overlap is the resonance region. The wiring 30a and 30b are made of materials such as aluminum or gold, or are made by laminating multiple different materials. With this configuration, when a high-frequency voltage is applied to the lower electrode 42 and the upper electrode 46, the resonator element 16a resonates bulk acoustic waves in a thickness extensional vibration mode or a thickness shear vibration mode within the resonance region. The piezoelectric layer 44 can be made of, for example, lithium tantalate, lithium niobate, or quartz. For example, it can be made of single-crystal rotated Y-cut X-propagation lithium tantalate or single-crystal rotated Y-cut X-propagation lithium niobate. The sensitive film 16b is laminated on the upper electrode 46 of the resonator element 16a. The surface of the sensitive film 16b forms part of the inner wall of the second flow path 14b.

[0029] The sensitive film 16b has a structure in which, for example, a conductive film is provided on the upper electrode 46, a self-assembled monolayer (SAM) with high affinity to the conductive film is provided on the conductive film, and an antibody is further provided on the SAM. As an example, the conductive film is composed of a film in which gold is laminated on a titanium base. The antibody reacts specifically with an antigen, which is a target substance in the specimen. The sensitive film 16b is not limited to the above configuration, as long as it reacts with the target substance in the specimen. Furthermore, examples of specimens containing target substances include biological samples such as saliva and blood. Target substances include proteins, antigens, viruses, etc.

[0030] [Heating Operation and Target Substance Detection] FIG. 4 is a block diagram showing an example of the configuration of the detection device 100, and FIG. 5 is a cross-sectional view showing an example of the flow state of the sample in the first flow path 14a when the heater 20 is activated. The detection device 100 is a device that measures a target substance in a sample using a fluid sensor, and is compatible with both resonance-type and delay-type fluid sensors. Note that the fluid sensor 1 shown in the first embodiment corresponds to a resonance-type configuration. Furthermore, although only the reference numeral for the fluid sensor 1 is shown in FIG. 4 , fluid sensors according to subsequent embodiments and their modifications can also be applied to the detection device 100. As shown in FIG. 4 , the detection device 100 includes a transmitter 101, a receiver 102, a measuring device 103, a detector 104, a heater power supply 105, and a temperature controller 106.

[0031] The fluid sensor is connected via terminals (not shown) to terminals corresponding to the transmitter 101, receiver 102, and measuring device 103 of the detection device 100. Furthermore, terminals at both ends of the heater 20 are connected to a heater power supply 105, and terminals at both ends of the temperature sensor 22 are connected to a temperature controller 106. In the case of a resonance type fluid sensor 1, they are connected to the transmitter 101 and measuring device 103.

[0032] The transmitter 101 transmits a high-frequency signal to the lower electrode 42 and the upper electrode 46 of the fluid sensor 1. This applies a high-frequency voltage to the lower electrode 42 and the upper electrode 46. In the case of a delay-type fluid sensor, the transmitter transmits the high-frequency signal to the measuring device 103 in addition to the comb electrode on the transmitting side. In the case of a delay-type fluid sensor, the receiver 102 receives the elastic wave signal received by the comb electrode on the receiving side. The received signal is output to the measuring device 103.

[0033] In the case of a resonance-type fluid sensor, the measuring device 103 measures, for example, the frequency of the oscillation signal output by the fluid sensor 1. On the other hand, in the case of a delay-type fluid sensor, the measuring device 103 measures, for example, the phase difference between the high-frequency signal transmitted by the transmitter 101 and the high-frequency signal received by the receiver 102. Note that this configuration is not limited, and the measuring device 103 may have other measurement modes, such as measuring the phase difference for a resonance-type fluid sensor. In the case of a resonance-type fluid sensor, for example, the detector 104 detects the target substance based on the amount of change in the frequency of the oscillation signal measured by the measuring device 103. On the other hand, in the case of a delay-type fluid sensor, for example, the detector 104 detects the target substance based on the amount of change in the phase difference measured by the measuring device 103.

[0034] Specifically, the measurement using the fluid sensor 1 involves, for example, propagating bulk acoustic waves to generate standing waves while the flow path 14 is filled with a liquid or specimen that does not contain a target substance, and measuring the frequency information at that time. Next, using a similar procedure, the frequency information is measured when the flow path 14 is filled with a specimen that contains a target substance. Meanwhile, the heater power supply 105 applies a voltage to both ends of the heater 20 in response to a command from the temperature controller 106. When a voltage is applied to the heater 20, a current flows through the heating wire 21, causing the heating wire 21 to heat due to the resistance of the conductor. The temperature controller 106 feedback-controls the operation of the heater power supply 105 based on the temperature of the specimen in the first flow path 14a measured by the temperature sensor 22, so as to maintain a desired, constant temperature. Specifically, the temperature controller 106 controls the applied voltage value of the heater power supply 105 so as to maintain a constant temperature at which the reaction between the target substance and the sensitive film 16b is promoted. For example, the applied voltage value of the heater power supply 105 is controlled to approximately 37°C.

[0035] As shown in FIG. 5 , the heater 20 heats the analyte 200 in the first flow path 14a, generating thermal convection due to the temperature gradient. The thermal convection is indicated by the arrows in FIG. 5 . In this manner, heat generated from the long portion 21a of the heating wire 21 is transferred from the surface of the first protective film 18 and directly to the analyte 200. This generates thermal convection toward the inner surface of the ceiling wall of the first flow path 14a. This thermal convection agitates the analyte 200 in the first flow path 14a, dispersing the target material 202 substantially uniformly throughout the analyte 200. FIGS. 6( a ) and 6 ( b ) are cross-sectional views illustrating an example of the distribution of the target material in the second flow path 14b with and without heating. Note that the arrows in FIGS. 6( a ) and 6 ( b ) indicate the direction of flow of the analyte 200.

[0036] The analyte 200 heated in the first flow path 14a and stirred by thermal convection flows from the first flow path 14a into the second flow path 14b. As a result, as shown in Fig. 6(a), the second flow path 14b is filled with the analyte 200 in which the target substance 202 is dispersed substantially uniformly. As a result, the number of target substances 202 that react with the antibody in the sensitive membrane 16b, indicated by "Y" in Fig. 6(a), increases, and the reaction between the antibody and the target substance 202 is promoted.

[0037] On the other hand, if stirring by heating is not performed, the target substances 202 in the specimen 200 will be unevenly distributed, such as overlapping on the tributary side of the second flow path 14b, as shown in Figure 6(b). As a result, the number of target substances 202 that do not react with the antibody on the sensitive membrane 16b, indicated by "Y" in Figure 6(b), will increase. Note that although the liquid reservoirs 26 and 32 are not shown in Figure 4, they may be provided separately from the detection device 100, or may be provided within the detection device 100.

[0038] [Agitation Effect Due to the Unevenness of the Heating Wire 21] Next, the agitation effect due to the heating wire 21 will be described. FIGS. 7(a) to 7(e) are diagrams showing examples of the wiring configuration of the heating wire 21, and FIGS. 7(f) and 7(g) are schematic diagrams showing examples of the shape of the flow path and the flow of the sample in each first flow path. The first protective film 18 is omitted in FIGS. 7(a) to 7(e). Note that in the configurations of FIGS. 7(b) to 7(e), the first protective film 18 is configured to cover each heating wire 21 along the uneven shape formed by each heating wire 21 and a portion of the main surface 12a. FIG. 7(f) shows the configuration of the flow path 14, and FIG. 7(g) shows the configuration of the flow path 14A. Flow path 14A is configured such that, instead of the second flow path 14b, a third flow path 14c with the same width as the first flow path 14a is provided.

[0039] That is, in the configuration of the flow path 14 shown in FIG. 7( f ), the first flow path 14 a and the second flow path 14 b have different widths, with the width of the first flow path 14 a being larger than the width of the second flow path 14 b. Therefore, as shown by the arrows in FIG. 7( f ), a straight flow from the −X direction toward the +X direction and a diagonal flow intersecting the X direction toward the second flow path 14 b are generated. Furthermore, if the width of the first flow path 14 a is larger than the width of the second flow path 14 b, the connection portion between the first flow path 14 a and the second flow path 14 b shown in FIG. 7( f ) does not need to have a discontinuous shape with a step at a right angle when viewed from above, but may have a continuous shape with a taper when viewed from above. On the other hand, in the configuration of the flow path 14A shown in FIG. 7( g ), the widths of the first flow path 14 a and the third flow path 14 c are the same, so only a straight flow is generated from approximately the −X direction toward the +X direction.

[0040] Here, Figure 7(a) shows the wiring configuration of the heating wire 21 of the heater 20, and with this wiring configuration, the long portion 21a intersects with both the sample flows shown in Figures 7(f) and 7(g). Therefore, the sample meanders at the uneven portion formed by the intersecting heating wire 21 and a portion of the main surface 12a, thereby enhancing the stirring effect. Note that the wiring configuration of the heating wire is not limited to the configuration shown in Figure 7(a) and other configurations may also be used. Below, configurations shown in Figures 7(b) to 7(e) will be described as other wiring configurations of the heating wire.

[0041] 7B shows the wiring configuration of the heating wire 21A of the heater 20A. This wiring configuration meanders from one end on the −X direction side to the other end on the +X direction side, and the long portion extending in the Y direction also meanders in the −Y direction or the +Y direction. That is, the wiring meanders from one end on the +Y direction side to the other end on the −Y direction side, turns back at the other end, and then repeats meandering from the other end on the −Y direction side to one end on the +Y direction side. With this configuration, in addition to having the same effect as the heating wire 21 of the heater 20, the unevenness caused by the meandering of the heating wire 21A in the Y direction can also cause the sample to meander, further enhancing the stirring effect.

[0042] 7(c) shows the wiring configuration of the heating wire 21B of the heater 20B. This wiring configuration is obtained by rotating the wiring configuration of FIG. 7(a) by 90° counterclockwise. This configuration exerts a stirring effect on the diagonal flow shown in FIG. 7(f).

[0043] FIG. 7(d) shows the wiring configuration of the heating wire 21C of the heater 20C. This wiring configuration is configured with the heating wire wire wired in a spiral shape. Specifically, multiple long portions extending in the Y and X directions are configured within the first flow path 14a, and these multiple long portions are arranged in parallel at predetermined intervals in the X and Y directions. This wiring configuration provides the same stirring effect as the wiring configurations of the heaters 20 and 20B of FIGS. 7(a) and 7(c) for both the sample flows shown in FIGS. 7(f) and 7(g). In particular, for sample flows in an oblique direction, both types of long portions contribute to the meandering of the sample. Therefore, the stirring effect can be enhanced compared to the wiring configuration of the heater 20 or 20B alone.

[0044] 7(e) shows the wiring configuration of the heating wire 21D of the heater 20D. This wiring configuration is configured so that the heating wire 21D is meandered in a direction perpendicular to the diagonal direction, forming multiple long portions extending diagonally across the X direction of the first flow path 14a. With this wiring configuration, multiple long portions arranged parallel to each other intersect with a straight flow. Therefore, the stirring effect is high for straight flows. Meanwhile, for diagonal flows, depending on the diagonal direction of the long portions, the long portions may be approximately perpendicular or may barely intersect, thereby enhancing the stirring effect for flows in one diagonal direction.

[0045] Effects of the First Embodiment As described above, the fluid sensor 1 according to the first embodiment includes the piezoelectric layer 44 having the main surface 12 a, the substrate 12 including the piezoelectric layer 44, the heater 20 provided on the main surface 12 a, the sensitive membrane 16 b provided on the main surface 12 a and having a surface on the opposite side to the piezoelectric layer 44 and reacting with a target substance, and the lower electrode 42 and the sensitive membrane 16 b laminated with the piezoelectric layer 44 sandwiched therebetween and for propagating an elastic wave in at least a region in the piezoelectric layer 44 where the piezoelectric layer 44 and the surface of the sensitive membrane 16 b overlap. and an upper electrode 46; a first flow path 14a provided on the main surface 12a and having a first inner wall, the inner wall including the first inner wall, the region, and the surface of the heater 20 becoming a flow path for the liquid when the liquid flows; and a second flow path 14b provided on the main surface 12a and communicating with the first flow path 14a, having a second inner wall, the inner wall including the second inner wall and the surface of the sensitive membrane 16b becoming a flow path for the liquid when the liquid flows, the second flow path 14b being downstream of the flow of the liquid from the first flow path 14a.

[0046] With this configuration, the heating wire 21, which is the heat generating portion of the heater 20, is disposed within the first flow path 14a. This improves the heat transfer rate to the sample within the flow path, and generates a relatively strong thermal convection in a short time, compared to a conventional configuration in which the heater is disposed outside the flow path. This improves the stirring efficiency of the sample and further promotes the reaction of the target substance with the sensitive membrane 16b, compared to conventional configurations. As a result, the sensing sensitivity of the target substance can be improved.

[0047] The fluid sensor 1 according to the first embodiment has a configuration in which the first flow path 14a has a plurality of linear elongated portions 21a extending in the width direction, which is the Y direction, of the first flow path 14a, and arranged in parallel at predetermined intervals along the length direction, which is the X direction, of the first flow path 14a. In addition, the first protective film 18 is formed along the uneven shape formed by the thickness and width of the heating wire 21, the spacing between the elongated portions 21a, and part of the main surface 12a.

[0048] With this configuration, in addition to the thermal convection generated by the heater 20, the elongated portion 21a of the heating wire 21 extending in the width direction of the first flow path 14a and the irregularities formed by a portion of the main surface 12a can enhance the stirring effect of the sample. This further promotes the reaction of the target substance with the sensitive membrane 16b, thereby further improving sensing sensitivity. Furthermore, in the fluid sensor 1 according to the first embodiment, the width of the first flow path 14a is configured to be larger than the width of the second flow path 14b. With this configuration, a larger amount of sample can be heated within the wider flow path, thereby improving stirring efficiency.

[0049] Furthermore, the detection device 100 according to the first embodiment can detect a target substance in a sample using the fluid sensor 1, allowing the target substance to be detected using a sensor with high sensing sensitivity. As a result, the target substance can be detected more accurately than in the past. Furthermore, the fluid sensor 1 according to the first embodiment is configured to include a temperature sensor 22 disposed in the first flow path 14a and detecting the temperature of the sample in the first flow path 14a. In addition, the detection device 100 according to the first embodiment is configured to include a temperature controller 106 that controls the temperature of the sample in the first flow path 14a based on the temperature of the sample measured by the temperature sensor 22. With this configuration, the temperature of the sample in the first flow path 14a can be maintained at an appropriate constant temperature that promotes a reaction with the target substance.

[0050] Second Embodiment Next, a second embodiment of the present invention will be described. FIGS. 8 to 11 are diagrams illustrating the second embodiment. Configuration FIG. 8 is a plan view showing the schematic configuration of a fluid sensor 1A according to the second embodiment, and FIG. 9 is a cross-sectional view taken along line B-B' in FIG. 8. The second embodiment differs from the first embodiment in that a SAW resonator element 16Aa is provided instead of the resonator element 16a of the first embodiment, and a substrate 12A is provided instead of the substrate 12. Below, components identical to those described in the first embodiment are denoted by the same reference numerals and will not be described again as appropriate. Differences from the first embodiment will be described in detail. As shown in FIGS. 8 and 9, the fluid sensor 1A includes a substrate 12A, a flow path 14, a heater 20, a temperature sensor 22, and a sensor unit 16A.

[0051] The substrate 12A is a substrate made of a piezoelectric material, and may be, for example, a lithium tantalate substrate, a lithium niobate substrate, or a quartz substrate. For example, it may be a single-crystal rotated Y-cut X-propagation lithium tantalate substrate or a single-crystal rotated Y-cut X-propagation lithium niobate substrate. The substrate 12A may also be configured with a piezoelectric film bonded directly or via an insulating layer to a support substrate such as a sapphire substrate, a silicon substrate, a spinel substrate, a quartz substrate, or a quartz substrate. In the second embodiment, as an example, the piezoelectric film is bonded to a support substrate via an insulating layer. The substrate 12A has a principal surface 12Aa. A portion of the principal surface 12Aa is a first region 12Ab, and a portion of the principal surface 12Aa that is different from the first region 12Ab is a second region 12Ac. The first region 12Ab and the second region 12Ac are indicated by dashed lines in FIG. 8 . The sensor unit 16A includes a SAW resonator element 16Aa (hereinafter simply referred to as the "resonator element 16Aa") and a sensitive film 16Ab. The resonator element 16Aa is provided in the second region 12Ac on the main surface 12Aa and in the second flow path 14b.

[0052] Specifically, the resonator element 16Aa includes a comb electrode 33 provided at the center in the X direction on the main surface 12Aa. Furthermore, the resonator element 16Aa includes a reflector 34 provided adjacent to the comb electrode 33 on the −X direction side of the main surface 12Aa and a reflector 36 provided adjacent to the comb electrode 33 on the +X direction side of the substrate 12A, with the comb electrode 33 sandwiched between them. The comb electrode 33 is configured such that a pair of electrodes are intersecting with each other so that their electrode fingers are staggered. The comb electrode 33 is connected to wiring 30Aa and 30Ab. The wiring 30Aa and 30Ab have the same configuration as the wiring 30a and 30b of the first embodiment. The wiring 30Aa is connected to a positive signal potential, and the wiring 30Ab is connected to a negative signal potential or ground potential.

[0053] The comb electrode 33 may be formed of a single layer of, for example, ruthenium (Ru), chromium (Cr), aluminum, titanium, copper, molybdenum, tungsten, tantalum, platinum (Pt), rhodium (Rh), or iridium (Ir), or a laminated film of a plurality of such films. For example, the comb electrode 33 may be formed of a film in which aluminum is laminated on a titanium lower layer. In the second embodiment, the reflectors 34 and 36 each have a lattice shape. The reflectors 34 and 36 may be formed primarily of at least one metal selected from aluminum, copper, and molybdenum. For example, the reflectors 34 and 36 may be formed of a film in which aluminum is laminated on a titanium lower layer.

[0054] Although not shown, the comb electrode 33 and the reflectors 34 and 36 are entirely covered by a second protective film 60 that protects the comb electrode 33 and the reflectors 34 and 36 from liquid analytes and the like that serve as samples. The second protective film 60 will be described later. The second protective film 60 covers the comb electrode 33 and the reflectors 34 and 36 according to the electrode shape of the comb electrode 33 and the shapes of the reflectors 34 and 36. That is, the second protective film 60 has an uneven shape that conforms to the uneven shape formed by the comb electrode 33 and a portion of the principal surface 12Aa and the uneven shape formed by the reflectors 34 and 36 and a portion of the principal surface 12Aa. Furthermore, in the example shown in FIG. 9 , a field short-circuiting film 62 is laminated on the second protective film 60. Details of the field short-circuiting film 62 will be described later. The field short-circuiting film 62 is laminated on the second protective film 60 according to the uneven shape of the second protective film 60. That is, the electric field short-circuiting film 62 has an uneven shape that matches the uneven shape of the second protective film 60 .

[0055] The sensitive film 16Ab has a configuration similar to that of the sensitive film 16b in the first embodiment, and is laminated on top of the electric field short-circuiting film 62. The sensitive film 16Ab is laminated on the electric field short-circuiting film 62 along the uneven shape of the electric field short-circuiting film 62. In other words, the sensitive film 16Ab has an uneven shape that follows the uneven shape of the electric field short-circuiting film 62.

[0056] In the resonator element 16Aa, an external high-frequency voltage is applied to the comb-shaped electrode 33, which excites the substrate 12A and generates surface acoustic waves with a wavelength corresponding to the electrode pitch. The generated surface acoustic waves propagate in the +X and -X directions on the surface of the substrate 12A that overlaps the surface of the sensitive film 16Ab, and are reflected by the reflectors 34 and 36. As a result, a standing wave of surface acoustic waves is formed on the piezoelectric substrate 12A sandwiched between the pair of reflectors 34 and 36, causing a resonance phenomenon. This resonance frequency changes depending on the amount of target substance on the surface of the sensitive film 16Ab.

[0057] Next, the detailed configuration of the substrate 12A and the comb-shaped electrode 33 portion of the resonator element 16Aa will be described. FIG. 10 is a partial cross-sectional view of a fluid sensor 1A according to the second embodiment. As shown in FIG. 10, the sensor portion 16A is formed on the piezoelectric layer 54 of the substrate 12A and is configured by stacking a first electrode layer 56, a second electrode layer 58, a second protective film 60, a field shunt film 62, and a sensitive film 16Ab. In the example shown in FIG. 10, the support substrate 49, the first bonding layer 50, the second bonding layer 52, and the piezoelectric layer 54 form the substrate 12A. In the example shown in FIG. 10, the first electrode layer 56, the second electrode layer 58, the second protective film 60, and the field shunt film 62 form the comb-shaped electrode 33 of the resonator element 16Aa.

[0058] The first bonding layer 50 and the second bonding layer 52 are made of oxide films. The oxide films can be made of a material selected from the group consisting of silicon oxide, tantalum pentoxide, and aluminum oxide, for example. The piezoelectric layer 54 has a configuration similar to that of the piezoelectric layer 44 of the first embodiment, and the first electrode layer 56 and the second electrode layer 58 are electrode layers that form the comb-shaped electrode 33. The second protective film 60 is made of an insulating film with a configuration similar to that of the first protective film 18 of the first embodiment. The electric field short-circuiting film 62 is made of a film of a metal material or the like, and has the function of short-circuiting the electric field and canceling the field effect. The electric field short-circuiting film 62 can be made of, for example, aluminum, gold, or the like.

[0059] As shown in FIG. 10 , the first and second electrode layers 56 and 58 constituting the comb-shaped electrode 33 and a portion of the principal surface 12Aa form an uneven surface. The protective film 60 and the electric field short-circuiting film 62 cover the first and second electrode layers 56 and 58 along the uneven surface formed by the first and second electrode layers 56 and 58 and a portion of the principal surface 12Aa. [Regarding the Heating Operation and the Stirring Effect of the Uneven Surface of the Sensor Unit 16A] FIGS. 11( a ) and 11 ( b ) are cross-sectional views showing an example of the distribution of the target substance in the second flow path 14 b with and without the heating operation. Note that the arrows in FIGS. 11( a ) and 11 ( b ) indicate the direction of flow of the analyte 200.

[0060] The analyte 200 heated and agitated by thermal convection in the first flow path 14a flows from the first flow path 14a to the second flow path 14b. As a result, as shown in FIG. 11(a), the second flow path 14b is filled with the analyte 200 in which the target substance 202 is dispersed uniformly. In addition, the analyte 200 flowing into the second flow path 14b meanders due to the unevenness of the sensor unit 16A, causing agitation due to this meandering. As a result, the number of target substances 202 reacting with the antibody ("Y" in FIG. 11(a)) in the sensitive membrane 16b increases compared to the configuration of the first embodiment, which only involves agitation by heating. As a result, the reaction between the antibody and the target substance 202 is more promoted compared to the configuration of the first embodiment.

[0061] On the other hand, when agitation by heating is not performed, as shown in Figure 11(b), the target substances 202 in the specimen 200 are unevenly distributed, such as being overlapped at the end of the second flow path 14b. Meanwhile, the specimen 200 that flows into the second flow path 14b meanders due to the unevenness of the sensor unit 16A, and agitation occurs due to this meandering. As a result, compared to when heating is not performed in the configuration of the first embodiment, the number of target substances 202 that react with the antibody in the sensitive membrane 16b ("Y" in Figure 11(b)) increases.

[0062] Effects of the Second Embodiment As described above, the fluid sensor 1A according to the second embodiment includes a resonant element 16Aa of a sensor unit 16A including a comb-shaped electrode 33 disposed at the center of the principal surface 12Aa in the X direction. Furthermore, the piezoelectric substrate 12A includes a reflector 34 disposed adjacent to the comb-shaped electrode 33 on the −X direction side of the principal surface 12Aa and a reflector 36 disposed adjacent to the comb-shaped electrode 33 on the +X direction side, sandwiching the comb-shaped electrode 33 therebetween. Additionally, the sensitive membrane 16Ab is formed along the uneven shape formed by the comb-shaped electrode 33 and a portion of the principal surface 12Aa, and along the uneven shape formed by the reflectors 34 and 36 and a portion of the principal surface 12Aa. With this configuration, the unevenness on the surface of the sensor unit 16 can agitate the sample even in the second flow path 14b where the sensitive membrane 16Ab is disposed. This further promotes the reaction of the target substance with the sensitive membrane 16b, thereby improving sensing sensitivity.

[0063] Third Embodiment Next, a third embodiment of the present invention will be described. FIGS. 12 and 13 are diagrams illustrating the third embodiment. Configuration FIG. 12 is a plan view showing the schematic configuration of a fluid sensor 1B according to the third embodiment, and FIG. 13 is a cross-sectional view taken along line CC' in FIG. 12. The third embodiment differs from the second embodiment in that a SAW delay element 16Ba is provided instead of the SAW resonator element 16Aa of the second embodiment. Below, components identical to those described in the second embodiment are denoted by the same reference numerals and will not be described again as appropriate. Differences from the second embodiment will be described in detail. As shown in FIGS. 12 and 13, the fluid sensor 1B includes a substrate 12A, a flow path 14, a heater 20, a temperature sensor 22, and a sensor unit 16B. The sensor unit 16B includes a SAW delay element 16Ba (hereinafter simply referred to as the "delay element 16Ba") and a sensitive membrane 16Bb. The delay element 16Ba is provided in the second region 12Ac on the principal surface 12Aa and in the second flow path 14b. Specifically, the delay element 16Ba includes a first comb electrode 64 on the principal surface 12Aa that transmits surface acoustic waves, a second comb electrode 66 on the surface acoustic wave receiving side, and an electric field short-circuit film 68 provided between the first comb electrode 64 and the second comb electrode 66.

[0064] The electric field short-circuiting film 68 is provided in the central portion of the second region 12Ac on the principal surface 12Aa in the X direction and extends in the X direction. The first comb electrode 64 is provided adjacent to the electric field short-circuiting film 68 on the −X direction side, and the second comb electrode 66 is provided adjacent to the electric field short-circuiting film 68 on the +X direction side. The first comb electrode 64 is connected to the wirings 30Ba and 30Bc. The second comb electrode 66 is connected to the wirings 30Bb and 30Bc. The wirings 30Ba and 30Bb have the same configuration as the wirings 30a and 30b in the first embodiment. The wirings 30Ba and 30Bb are connected to a signal potential, and the wiring 30Bc is connected to a ground potential. The first comb electrode 64 and the second comb electrode 66 have the same configuration as the comb electrode 33 in the second embodiment.

[0065] The electric field shunt film 68 is a film for short-circuiting the electric field on the propagation surface of the surface acoustic wave and is composed of a film similar to the electric field shunt film 62 of the second embodiment. For example, it can be composed of aluminum, gold, or the like. Furthermore, if the electric field shunt film 68 is composed of gold, a chromium or titanium layer may be provided between the gold and the principal surface 12Aa to ensure adhesion to the piezoelectric film. The electric field shunt film 68 may also be provided on the first comb electrode 64 and the second comb electrode 66. This can suppress the generation of unnecessary capacitance due to changes in the dielectric constant of the liquid sample in the first comb electrode 64 and the second comb electrode 66. The sensitive film 16Bb has a configuration similar to the sensitive film 16Ab of the second embodiment and is provided on the electric field shunt film 68. Furthermore, since the first comb electrode 64 and the second comb electrode 66 are provided within the second flow path 14b, a second protective film 60 is provided on their tops. The second protective film 60 covers the first comb electrode 64 and the second comb electrode 66 along the uneven shape formed by the first comb electrode 64, the second comb electrode 66, and a portion of the principal surface 12Aa. That is, the second protective film 60 has an uneven shape that follows the uneven shape formed by the first comb electrode 64, the second comb electrode 66, and a portion of the principal surface 12Aa.

[0066] With this configuration, surface acoustic waves generated by applying a high-frequency voltage to the first comb electrode 64 in the transmitter 101 of the detection device 100 according to the first embodiment propagate over the electric field short-circuiting film 68, proceed in the +X direction, and reach the second comb electrode 66. That is, the surface acoustic waves transmitted by the first comb electrode 64 cross the portion of the substrate 12A that overlaps with the sensitive film 16Bb and reach the second comb electrode 66. The second comb electrode 66 converts the received surface acoustic waves into a signal and outputs it to the receiver 102. Therefore, the measuring device 103 measures the phase difference between the high-frequency signal transmitted by the transmitter 101 and the high-frequency signal received by the receiver 102, and the detector 104 can detect a target substance in a sample based on the measured phase difference.

[0067] Furthermore, due to the uneven shape of the first comb electrode 64, the second comb electrode 66, and a portion of the main surface 12Aa, the sample 200 that flows from the first flow path 14a to the second flow path 14b meanders around the uneven portions, causing agitation. This increases the number of target substances 202 that react with the antibodies on the sensitive membrane 16Bb compared to the configuration of the first embodiment, which only involves agitation by heating. As a result, the reaction between the antibodies and the target substances 202 is more promoted compared to the configuration of the first embodiment.

[0068] Effect of the Third Embodiment As described above, the fluid sensor 1 according to the third embodiment is configured such that the delay element 16Ba of the sensor section 16B includes a first comb electrode 64 on the transmitting side of the surface acoustic waves, a second comb electrode 66 on the receiving side of the surface acoustic waves, and an electric field short-circuit film 68 provided between the first comb electrode 64 and the second comb electrode 66, which are provided on the main surface 12Aa.

[0069] In addition, a third protective film is formed along the uneven shape formed by the first comb electrode 64 and the second comb electrode 66 and part of the principal surface 12Aa, covering the first comb electrode 64 and the second comb electrode 66. That is, the third protective film has an uneven shape that follows the uneven shape formed by the first comb electrode 64 and the second comb electrode 66 and part of the principal surface 12Aa.

[0070] With this configuration, the uneven shape of the first comb electrode 64, the second comb electrode 66, and part of the main surface 12Aa can stir the sample even within the second flow path 14b in which the sensitive membrane 16Bb is arranged, thereby further promoting the reaction of the target substance with the sensitive membrane 16b and further improving sensing sensitivity.

[0071] [Modification] In the third embodiment, the first and second comb electrodes 64 and 66 of the delay element 16Ba are disposed within the second flow path 14b. However, this configuration is not limiting. For example, as long as the metal layer and sensitive film through which the surface acoustic waves propagate are disposed within the second flow path 14b, the first and second comb electrodes 64 and 66 may be disposed outside the second flow path 14b. A specific example will be described below. FIG. 14 is a plan view showing the schematic configuration of a fluid sensor 1C according to a modification, and FIG. 15 is a cross-sectional view taken along line D-D' in FIG. 14. As shown in FIGS. 14 and 15, the fluid sensor 1C includes a substrate 12C, a flow path 14C, a heater 20, a temperature sensor 22, and a sensor unit 16C. The substrate 12C has a similar configuration to the substrate 12A, except for its dimensions in the X and Y directions. Specifically, compared to substrate 12A, substrate 12C is configured to be shorter in the X direction and longer in the Y direction. Substrate 12C has a main surface 12Ca. A portion of main surface 12Ca is a first region 12Cb, and a portion of main surface 12Ca that is different from first region 12Cb is a second region 12Cc. First region 12Cb and second region 12Cc are regions indicated by dashed lines in FIG. 14 .

[0072] The flow path 14C has a first flow path 14Ca and a second flow path 14Cb. The first flow path 14Ca has a configuration similar to that of the first flow path 14a in the first to third embodiments. The second flow path 14Cb communicates with the first flow path 14Ca and has a configuration in which the dimension in the X direction is shorter and the dimension in the Y direction is longer than that of the second flow path 14b in the first to third embodiments.

[0073] The sensor unit 16C has a configuration obtained by rotating the sensor unit 16B of the third embodiment approximately 90 degrees counterclockwise. Specifically, the sensor unit 16C has a configuration in which the center portion of the electric field short-circuit film 68 and the sensitive film 16Bb formed thereon are disposed within the second flow path 14Cb. Furthermore, the first comb electrode 64 is disposed adjacent to the +Y direction side of the outer wall forming the second flow path 14Cb, and the second comb electrode 66 is disposed adjacent to the -Y direction side of the outer wall forming the second flow path 14Cb. This configuration achieves the same functions and effects as the third embodiment. Furthermore, since protective films are not required for the first and second comb electrodes 64 and 66, costs can be reduced.

[0074] This configuration can also be applied to the sensor unit 16A of the second embodiment. That is, in the fluid sensor 1C, the sensor unit 16A is applied instead of the sensor unit 16C. In this case, the reflectors 34 and 36 are disposed outside the second flow path 14Cb.

[0075] Furthermore, in the first to third embodiments and their modifications, the fluid sensors 1, 1A, and 1B are configured to be mounted singly on a substrate. However, this configuration is not limited to this. For example, multiple fluid sensors may be arranged side by side in the Y direction on the same substrate. Furthermore, in this configuration, a heater may be shared among the multiple fluid sensors. A specific example will be described below. FIG. 16 is a plan view showing the schematic configuration of a fluid sensor 1D according to a modification, which has two flow paths and two sensor units. As shown in FIG. 16, the fluid sensor 1D includes a substrate 12D, a heater 20E, two flow paths 14, and two sensor units 16A. Specifically, the fluid sensor 1D has two fluid sensors 1A according to the second embodiment arranged side by side in the Y direction on the main surface 12Da of the substrate 12D, and the heaters 20 of these two fluid sensors 1A are replaced with a single shared heater 20E. The substrate 12D has a different dimension in the Y direction from the substrate 12A of the second embodiment, but has the same configuration as the substrate 12A except for the dimension.

[0076] The heating wire 21E of the heater 20E is routed in a large, serpentine pattern from one flow path to the other, passing through the outer gap between the upper and lower flow paths 14a, so that it is disposed within both the flow paths. The wiring configuration of the heating wire 21E is similar to that of the heating wire 21 of the heater 20 in each of the above-described embodiments, but other wiring configurations, such as those shown in Figures 3(b) to 3(e), may also be used. A liquid reservoir 26a is connected to the upper first flow path 14a via a joint 28a and a tube 24a, and a liquid reservoir 32a is connected to the upper second flow path 14b via a joint 28b and a tube 24b. A liquid reservoir 26b is connected to the lower first flow path 14a via a joint 28c and a tube 24c, and a liquid reservoir 32b is connected to the lower second flow path 14b via a joint 28d and a tube 24d.

[0077] This configuration allows different liquids to be supplied to the upper and lower flow paths 14, respectively. For example, a reference liquid and a liquid (analyte) containing a target substance can be supplied, and the measurement results can be compared. While the example shown in FIG. 16 does not include a temperature sensor 22, this configuration is not limiting. A temperature sensor 22 may be provided in each first flow path 14a, or only one of the first flow paths 14a may be provided. While the above configuration illustrates connecting the reservoirs 32a and 32b to the second flow paths 14b of the upper and lower flow paths 14, this configuration is not limiting. For example, the discharge reservoirs 32a and 32b may be formed from a single reservoir. In this case, for example, a bifurcated tube may be used to connect the reservoir to the upper and lower second flow paths 14b. In addition, in the above configuration, the sensitive film 16Ab is provided on the comb-shaped electrodes 33 of both the upper and lower SAW resonator elements 16Aa, but this configuration is not limited to this, and the sensitive film 16Ab may be provided on only one of them.

[0078] In the first embodiment and its modifications, the first protective film 18 is provided along the uneven surface formed by the heating wire 21 and the main surface 12a. However, this configuration is not limited to this. For example, the first protective film 18 may be provided so as to have a flat surface, thereby eliminating the unevenness caused by the heating wire 21. In the first embodiment and its modifications, the acoustic reflection film 40 constituting the resonator element 16a may be replaced by forming a laminate including the lower electrode 42 on the support substrate 39, and then forming a recess in the support substrate 39 to form a void, or by forming a sacrificial layer between the lower electrode 42 and the support substrate 39 and removing it by etching to form a void. These structures constitute a film bulk acoustic resonator (FBAR).

[0079] 1, 1A to 1D... fluid sensor, 12, 12A, 12C, 12D... substrate, 14, 14C... flow path, 14a, 14Ca... first flow path, 14b, 14Cb... second flow path, 16, 16A to 16C... sensor unit, 16a... resonance element, 16Aa... SAW resonance element, 16Ba... SAW delay element, 16b, 16Ab, 16Bb... sensitive film, 18... first protective film, 20, 20A to 20E... heater, 21, 21A to 21E... heating wire, 22... temperature sensor, 23... metal wire, 24a to 24d... tube, 26, 26a, 26b, 32, 32a, 32b... liquid reservoir, 28a to 28d... joint, 30a , 30b, 30Aa, 30Ab, 30Ba to 30Bc...wiring, 33...comb-shaped electrode, 34, 36...reflector, 39, 49...support substrate, 40...acoustic reflection film, 42...lower electrode, 44...piezoelectric film, 46...upper electrode, 50...first bonding layer, 52...second bonding layer, 54...piezoelectric layer, 56...first electrode layer, 58...second electrode layer, 60...second protective film, 62, 68...field short-circuit film, 64...first comb-shaped electrode, 66...second comb-shaped electrode, 100...detection device, 101...transmitter, 102...receiver, 103...measuring instrument, 104...detector, 105...heater power supply, 106...temperature controller, 200...analyte, 202...target substance

Claims

1. A piezoelectric body having a main surface, a substrate including the piezoelectric body, a heater provided on the main surface, a sensitive film provided on the main surface, having a surface on the side opposite to the piezoelectric body side, and reacting with a target substance, and provided on the main surface, and at least the main surface and the surface in the piezoelectric body A pair of electrodes for propagating elastic waves in an overlapping region, a first flow path provided on the main surface, having a first inner wall, and when a liquid flows, the first inner wall, the region, and the inner wall including the surface of the heater become a liquid flow path, and the first flow path is provided on the main surface and communicates with the first flow path, has a second inner wall, and when a liquid flows, the second inner wall and the inner wall including the surface become a liquid flow path, and is a second flow path downstream of the liquid flow from the first flow path, a sensor comprising.

2. The sensor according to claim 1, wherein the heater has a plurality of linear heating portions extending in the width direction of the first flow path and arranged in parallel at a predetermined interval along the length direction which is a direction orthogonal to both the width direction and the height direction of the first flow path.

3. The sensor according to claim 1, wherein the heater extends in an oblique direction intersecting the length direction which is a direction orthogonal to the width direction and the height direction of the first flow path, and a plurality of linear heating portions arranged in parallel at a predetermined interval along a direction orthogonal to the oblique direction respectively.

4. The sensor according to claim 1, wherein a protective film is formed along the uneven shape formed by the heating portion and a part of the main surface.

5. The sensor according to claim 1, wherein the width of the first flow path is configured to be larger than the width of the second flow path.

6. The sensor according to claim 1, further comprising a temperature sensor provided in the first flow path for detecting the temperature of the sample in the first flow path.

7. The sensor according to claim 1, wherein the pair of electrodes are a pair of comb-shaped electrodes provided under the sensitive film on the piezoelectric body, and the sensor unit is provided in the second region on the main surface, and in the traveling direction of the elastic wave, reflectors provided at positions facing each other with the pair of comb-shaped electrodes interposed therebetween.

8. The sensor according to claim 7, wherein the sensitive film is formed along the electrode shape of the comb-shaped electrode.

9. The sensor according to claim 1, wherein the pair of electrodes are a pair of first comb-shaped electrodes for transmitting the elastic wave and a pair of second comb-shaped electrodes for receiving the elastic wave, which face each other with the sensing film therebetween in the length direction that is orthogonal to the width direction and the height direction of the second flow path.

10. The sensor according to claim 9, wherein the sensing film is formed along the electrode shapes of the first comb-shaped electrode and the second comb-shaped electrode.

11. The sensor according to claim 1, wherein the pair of electrodes are a first electrode and a second electrode laminated with the piezoelectric body therebetween, and the sensing film is provided at a position where the surface overlaps with the first electrode and the second electrode in the lamination direction.

12. A detection device comprising: a power supply for supplying power to the heater of the sensor according to any one of claims 1 to 11; a transmitter for transmitting a high-frequency signal for generating the elastic wave to the pair of electrodes of the sensor; a measuring device for measuring information on the elastic wave propagated to a portion where the piezoelectric body and the surface overlap; and a detector for detecting the target substance based on the information measured by the measuring device.

13. The detection device according to claim 12, wherein the sensor has a temperature sensor for detecting the temperature of the specimen in the first flow path, and further comprises a temperature controller for controlling the temperature of the specimen in the first flow path based on the temperature measured by the temperature sensor.

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