Odor sensor module and odor sensor device

Abstract

To provide an odor sensor module and an odor sensor device which are suitable for miniaturization and capable of enhancing efficiency and accuracy of odor substance detection.SOLUTION: A sensor module comprises: a semiconductor integrated circuit with a first circuit at one side among two opposite sides and a second circuit at the other side which is implemented on a print circuit board; a first odor detection element which is implemented on the print circuit board, arranged in the vicinity of one side of the semiconductor integrated circuit, and oscillated by the first circuit; and a second odor detection element which is implemented on the print circuit board, arranged in the vicinity of the other side of the semiconductor integrated circuit, and oscillated by the second circuit. The semiconductor integrated circuit, the first odor detection element, and the second odor detection element are arranged in a flow channel where gas flows and arrayed in a gas flowing direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an odor sensor module and an odor sensor device for measuring odors. [Background technology]

[0002] There are known methods for detecting odorants that utilize the resonance frequency shift caused by adding mass to piezoelectric vibrators such as QCM (Quartz Crystal Microbalance), SAW (Surface Acoustic Wave) resonators, and FBAR (Film Bulk Acoustic Resonators).Known methods for detecting the resonance frequency include a method using a measuring device such as a vector network analyzer, a method using a detection circuit that combines an oscillator circuit and a counter circuit, and a measurement method that converts frequency into voltage using a phase shifter and a mixer (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-115927 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to modularize a piezoelectric vibrator-type odor sensor, it is necessary to measure the frequency on a circuit board, and measurement using an oscillator circuit and a counter circuit is the most effective. Because the sensitivity of a piezoelectric vibrator-type odor sensor is proportional to the square of the resonance frequency, a piezoelectric vibrator with a high resonance frequency is suitable. The oscillator circuit and counter circuit can be realized using a printed circuit board and discrete components, but since the use of multiple components makes them prone to becoming large, and because they are high-frequency circuits, consideration must be given to reducing the inductance of the wiring pattern on the printed circuit board in order to achieve high detection accuracy, and the routing of the wiring and thin metal wires is important. In view of the above circumstances, an object of the present invention is to provide an odor sensor module and an odor sensor device that are suitable for miniaturization and that can achieve high efficiency and high accuracy in detecting odorous substances. [Means for solving the problem]

[0005] The present invention has been made in view of the above-mentioned problems, First, a semiconductor integrated circuit mounted on a printed circuit board, the semiconductor integrated circuit having a first circuit formed on one of opposing sides and a second circuit formed on the other of opposing sides; a first odor detection element that is mounted on the printed circuit board, arranged close to one side of the semiconductor integrated circuit, and oscillated by the first circuit; a second odor detection element mounted on the printed circuit board, arranged adjacent to the other side of the semiconductor integrated circuit, and oscillated by the second circuit; The semiconductor integrated circuit, the first odor detection element, and the second odor detection element are disposed in a flow path through which a gas passes, and are aligned along the direction of the gas flow. This problem is solved by using an odor sensor module. Second, This problem is solved by making the thicknesses of the semiconductor integrated circuit, the first odor detection element, and the second odor detection element the same. Third, the semiconductor integrated circuit is rectangular in plan view, The one side and the other side are short sides of the semiconductor integrated circuit, and the long side of the semiconductor integrated circuit is parallel to the direction of the gas flow, thereby solving the problem. Fourth, The semiconductor integrated circuit solves the problem by including a counter circuit that is provided between the first circuit and the second circuit and that counts the frequencies of the first circuit and the second circuit. Fifth, a first thin metal wire that electrically connects the semiconductor integrated circuit and the first odor detection element; a second thin metal wire electrically connecting the semiconductor integrated circuit and the second odor detection element; This problem can be solved by having the following. Sixth, The first thin metal wire and the second thin metal wire are arranged along the direction of the gas flow, thereby solving the problem. Seventh, This problem is solved by mounting components only in the area outside the long sides on the surface of the printed circuit board. Eighth, the odor sensor module is provided in a sensor chamber that forms the flow path, and the flow path is provided with an inlet and an outlet; A gas transfer device is provided at the inlet or outlet. This problem can be solved with an odor sensor device. Ninth, The gas transfer device is a pump, and the sensor chamber is resolved by varying the pressure to either positive or negative. [Effects of the Invention]

[0006] As described above, according to the present invention, it is possible to provide an odor sensor module and an odor sensor device that are suitable for miniaturization and that can achieve high efficiency and high accuracy in detecting odorous substances. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view of an odor sensor device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of FIG. [Figure 3] FIG. 2 is a diagram illustrating the thickness of a channel and a chip. [Figure 4] FIG. 2 is a perspective view of the odor sensor device. [Figure 5] FIG. 2 is an exploded view of the odor sensor device. [Figure 6] FIG. 2 is a diagram illustrating the connection between the semiconductor integrated circuit and the odor detection element. [Figure 7] FIG. 2 is a cross-sectional view of the odor sensor device. [Figure 8]FIG. 2 is a diagram illustrating a sensor substrate. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention relates to an odor sensor module and an odor sensor device using the same. The characteristics and schematic structure of the odor sensor module will be described below with reference to FIGS. 1 to 3, and then an embodiment of the sensor device will be described. In the following, the term "odor sensor" will be abbreviated to "sensor module." The odor detection element and the odor sensor are equivalent. Odor sensors that detect odors can be divided into two types based on their principles: resistance type, which detects changes in the resistance value of a sensitive film, and oscillator type, which attaches a sensitive film to a resonating part such as a quartz oscillator or piezoelectric element and detects odors from changes in the frequency of vibration. In particular, in the case of oscillator-type sensors, it is common to use an oscillator circuit and a frequency counter to detect changes in the oscillation frequency. In this invention, this oscillator circuit is placed inside an IC, and this IC is used to create an odor sensor module. There are some clever ideas behind this, which I will explain below.

[0009] [About odor detection elements] As shown in Figures 1 and 2, To measure odors, a sensitive membrane that adsorbs and desorbs odors is required, and a first odor detection element 10A having this membrane and a second odor detection element 10B for reference are used. For this reason, it is preferable that the two odor detection elements 10A and 10B have approximately the same shape and comparable characteristics. These two odor detection elements 10A and 10B with approximately the same shape and comparable characteristics are mass-produced using semiconductor technology. These odor detection elements are arranged in a matrix on a semiconductor wafer, which is then diced into dice (rectangular) shapes. The individual odor detection elements mass-produced on this wafer are what we refer to as "approximately the same shape and have equivalent characteristics." Preferably, the elements are adjacent to each other on the wafer. The second odor detection element 10B may have a sensitive membrane and be used for odor detection. When used for odor detection, the sensitive membrane may be made of a material different from that of the first odor detection element 10A, thereby making it an odor sensor that easily adsorbs and desorbs different odors. In this case, it is preferable that the two odor detection elements 10A and 10B have approximately the same shape and similar characteristics. These two odor detection elements 10A and 10B are connected to an oscillation circuit. The odor detection elements 10A and 10B are mounted face-up, with a sensitive film provided on the resonator portion 11 on the surface, and wiring L and bonding pads E that form the oscillator are provided around the sensitive film.

[0010] The odor detection elements 10A and 10B in FIG. 1 are FBARs (Film Bulk Acoustic Resonators), and the electrodes sandwiching the piezoelectric material that forms the resonating portion are connected to surrounding bonding pads E via wiring L. The same is true for quartz crystal resonators. Furthermore, the SAW is provided with bonding pads E extending from a pair of comb-shaped electrodes. Both the quartz crystal resonator and the FBAR have a sensitive film provided in the resonating portion. The odor detection elements 10A and 10B are mounted on a printed circuit board 30, similar to the semiconductor integrated circuit 20 described below. The two input bonding pads E of the odor detection elements 10A and 10B can be substituted by bonding pads E provided around the chip or wiring L. This is because the wiring L is larger in size than the pattern of the semiconductor integrated circuit 20. Preferably, the bonding pad E is disposed on the side opposite to the short side of the semiconductor integrated circuit 20, and this is used as the bonding pad. However, in this embodiment, bonding is performed on the thick portion of the wiring. The semiconductor integrated circuit 20 and odor detection elements 10A and 10B are arranged in a flow path through which gas passes. The direction of gas flow is indicated by arrows in Figure 1. The semiconductor integrated circuit 20 and odor detection elements 10A and 10B are aligned along the direction of gas flow.

[0011] [Semiconductor integrated circuits and mutual interference] The two oscillator circuits A and B are connected to and oscillate with odor detection elements 10A and 10B, which have the same characteristics, and therefore have substantially the same vibration frequency band. However, when detecting an odor, the two odor detection elements 10A and 10B oscillate at different frequencies. This is because the odor is either adsorbed or desorbed by only one of the odor detection elements 10A and 10B, or by both, but the adsorption and desorption characteristics are different. This causes a change in the resonant frequency due to the different mass loads. In this case, depending on the arrangement of the two oscillator circuits A and B and the two odor detection elements 10A and 10B, mutual frequency interference may occur between the two oscillator circuits A and B, causing them to oscillate at the same frequency. Therefore, measures to prevent this are required. One of the measures is In order to incorporate two oscillator circuits A and B into an integrated circuit, the chip is made long and narrow. In other words, it is rectangular in plan view. The first oscillator circuit A is mainly formed on one short side 21 (here, the left side) of this rectangle. The second oscillator circuit B is mainly formed on the other short side 22 (the right side). Between oscillator circuit A and oscillator circuit B, a frequency counter C is mainly provided, which is electrically connected to the two oscillator circuits A and B. These three circuits are generally configured as a circuit block pattern. When a circuit is formed in a certain block area, the function / circuit may not be complete, and necessary circuits may exist in other locations. For this reason, the sentence uses "mainly" to say, "The oscillator circuit is mainly formed on the short side."

[0012] As shown in Figure 1, a semiconductor integrated circuit 20 is mounted on a printed circuit board 30. If the chip is rectangular in plan view, with a frequency counter C placed in the middle and oscillator circuits A and B placed on either side, the placement area for counter C can be used to separate the two oscillator circuits A and B. The presence of counter C between the two oscillator circuits A and B prevents leakage current flowing from one oscillator circuit to the semiconductor from reaching the other oscillator circuit and causing noise. Furthermore, since a distance can be provided between the two oscillator circuits A and B, noise due to mutual interference can be reduced. The semiconductor integrated circuit 20 is a compound semiconductor or Si chip, in which a diffusion region is formed in the active region on the surface, and the conductive pattern formed on the surface of this region is connected to transistors and the like formed on the surface, thereby incorporating a circuit. Furthermore, bonding pads connected to the conductive patterns are provided near the short sides 21, 22 and long sides 23, 24 of the semiconductor integrated circuit 20. Bonding pads 25, 26 on the short sides are terminals connected to the odor detection element. Bonding pads 27, 28 on the long sides are portions to which the power supply, GND, or control signal of the frequency counter C is input. Bonding pad E of the odor detection element and bonding pads 25, 26 on the short sides are connected by thin metal wire W1. Bonding pads 27, 28 on the long sides 23, 24 are connected by thin metal wire W2.

[0013] Generally, the bonding pads are located between the circuit blocks and the short sides 21, 22 or the long sides 23, 24 of the semiconductor integrated circuit 20. In other words, the bonding pads are scattered around the periphery of the semiconductor integrated circuit 20. 2, the semiconductor integrated circuit 20 is arranged so that its long sides 23 and 24 are parallel to the direction of gas flow indicated by the arrow. Odor detection elements 10A and 10B are mounted on a printed circuit board 30 adjacent to one short side 21 and the other short side 22 of the semiconductor integrated circuit 20, and bonding pads 25 and 26 are provided on the short sides of the semiconductor integrated circuit 20. With this arrangement, the first oscillator circuit A is located on one short side 21 of the semiconductor integrated circuit 20, so the first odor detection element 10A can be located close to the first oscillator circuit A. Furthermore, the second oscillator circuit B, located on the other short side 22 of the semiconductor integrated circuit 20, can also be located close to the second odor detection element 10B. Therefore, the distance between the four interconnecting thin metal wires W1 can be shortened. Because the thin metal wires W1 are short, the inductance of the thin metal wires can be reduced, allowing the oscillator circuits A and B to oscillate stably. Furthermore, because the semiconductor integrated circuit 20 incorporates two oscillator circuits A and B, the mounting size can be reduced when mounted on a printed circuit board 30.

[0014] [Printed circuit board] The printed circuit board 30, which is a mounting substrate, has a conductive pattern formed at least on its surface and has mounting areas for three semiconductor chips. This conductive pattern includes pad electrodes to which thin metal wires are connected, island electrodes to which the backside of the semiconductor chips is connected, and further wiring that extends integrally with the pad electrodes or island electrodes. The arrangement portion of the island electrode located in the center of this printed circuit board 30 is the mounting area for the semiconductor integrated circuit 20, and the semiconductor integrated circuit 20 is solder-mounted thereon. The arrangement portions of the island electrodes provided on the short sides 21 and 22 of the semiconductor integrated circuit 20 are the arrangement areas for the odor detection elements 10A and 10B, and the odor detection elements 10A and 10B are fixed thereon with solder. Power supply terminals, ground terminals, control terminals, and the like are provided on the printed circuit board 30 in the vicinity of the long sides of the semiconductor integrated circuit 20. Mounted components such as power supply ICs and capacitors connected to the semiconductor integrated circuit 20, as well as wiring for electrical connection between the mounted components, may be provided on the surface of the printed circuit board 30. In this case, if gas flows in the direction in which the odor detection elements 10A, 10B and the semiconductor integrated circuit 20 are aligned in a straight line, the mounted components may be provided only in the area outside the long sides of the semiconductor integrated circuit 20 on the printed circuit board 30. In this case, the gas flowing toward the odor detection elements 10A, 10B can be directly directed thereto without being obstructed by the mounted components, preventing a decrease in detection accuracy. Furthermore, providing wiring only in the area outside the long sides of the semiconductor integrated circuit 20 further reduces the amount of gas that is obstructed. In order to reduce the thermal effects on the odor detection elements 10A and 10B, the power supply IC connected to the semiconductor integrated circuit 20 may be provided on a circuit board separate from the printed circuit board 30, and the semiconductor integrated circuit 20 may be controlled by wiring and connecting the circuit board to the printed circuit board 30.

[0015] As described above, this printed circuit board 30 has the semiconductor integrated circuit 20 and two odor detection elements 10A, 10B mounted on it. In this case, this printed circuit board 30 functions as a single unit, making it possible to measure gases such as alcohol. However, because odors are a mixture of multiple components, multiple printed circuit boards 30 are arranged side by side. The odor detection elements on each printed circuit board 30 are provided with different sensitive films, and by examining their frequency changes, various odors can be identified. (Details will be provided in Figure 5.) This printed circuit board 30 is provided inside a sensor chamber 40, which is a flow path. In this embodiment, the surface of the printed circuit board 30 forms the inner wall of the sensor chamber 40, and the other side and top surfaces of the internal space are formed by the inner side walls or the inner wall of the lid that form the housing 41. In Figure 3, a solid-line rectangle 50 is shown that includes the surface of the printed circuit board 30. In other words, this part indicates the inner wall of the sensor chamber 40. In FIG. 7, which will be described later, it can be seen that only the surface of the sensor substrate 102 indicated by the reference numeral 102 is exposed to the sensor chamber 40 .

[0016] [Relationship between the direction of the metal wire and the flow path containing odor] As described above, the printed circuit board 30, on which the semiconductor integrated circuit 20 and the two odor detection elements 10A, 10B at both ends are mounted, is housed in the sensor chamber 40. In other words, the printed circuit board 30 is installed in the flow path. In FIG. 1, there are rectangular parallelepipeds indicated by solid lines, and the outermost rectangular parallelepiped is the sensor chamber 40, which also serves as the flow path. The outside of this sensor chamber 40 is the housing 41. Although the sensor chamber 40 appears large in the drawing, it is only a few millimeters high from the surface of the printed circuit board 30 or the surface of the odor detection elements 10A, 10B to the ceiling, and its cross-sectional area is also small, so the gas flowing into the sensor chamber 40 flows through a narrow space via a pump. As a result, the flow speed of the gas transferred by the pump is high. The inlet 60 is diagonally upward to the right of FIG. 1, and the outlet 61 is diagonally downward to the left. The inlet 60 is located upstream of the gas flow, and the outlet 61 is located downstream. A gas transfer device such as a pump is connected to a flow path that connects the inlet 60 or the outlet 61 to the outside. 5, gas is supplied to sensor chamber 40 using pump 109. In this case, when pump 109 sucks gas from flow path 151 and exhausts gas from sensor chamber 40 to flow path 153, sensor chamber 40 becomes positive pressure. On the other hand, when pump 109 sucks gas from flow path 153 and supplies gas to sensor chamber 40, and exhausts gas via flow path 151, sensor chamber 40 becomes negative pressure. In either case, pressure fluctuations occur via the pump.

[0017] On the other hand, the thin metal wire W1 electrically connecting the semiconductor integrated circuit 20 to the first odor detection element 10A and the thin metal wire W1 electrically connecting the semiconductor integrated circuit 20 to the second odor detection element 10B handle high-frequency signals, so even slight movement of the thin metal wire must be prevented. Wire movement leads to inductance fluctuations. High-frequency signals flow through the wires connected to the FBAR, which is the odor detection element, and when the FBAR is viewed from the semiconductor integrated circuit 20, it appears as if there is inductance on both ends of the resonator. This inductance changes not only with the length and diameter of the wire, but also with the degree of bending, so it is affected by air currents, which in turn affects the oscillation characteristics and causes noise. That is, the thin metal wire W1 is provided along the flow direction of the flow path (indicated by the arrow) to avoid the influence of air currents and pressure. Meanwhile, a plurality of bonding pads are provided along the two long sides 23, 24 of the semiconductor integrated circuit 20. Corresponding to these bonding pads, a plurality of bonding pads are also provided on the printed circuit board 30, and the thin metal wires W2 connecting these are provided in a direction intersecting the long sides, i.e., in a direction intersecting the flow direction. These wires are used for signals and power supplies for driving the IC, and are not like the ultra-high frequency signals handled by the thin metal wires W1, and do not require precision.

[0018] [Chip thickness of semiconductor integrated circuit and odor detection element] Semiconductor chips vary in wafer size and thickness depending on the semiconductor manufacturer's process and manufacturing conditions, and the thickness of the finished chips also varies. The thickness of all the semiconductor integrated circuit 20 and odor detection elements 10A and 10B chips can be made uniform by grinding down the backside of the chips, which allows the thin metal wires connecting them to be shortened. 3 shows the first and second odor detection elements 10A and 10B and the semiconductor integrated circuit 20 having the same chip thickness. Reference numeral 30 denotes a printed circuit board. For example, if the semiconductor integrated circuit 20 is thin and the odor detection elements 10A and 10B are thick, the thin metal wire W1 will need to have an extra length to fall, and the length of the thin metal wire W1 will be long. However, if the thickness of the three chips is substantially the same, the length of each thin metal wire W1 can be shortened. Therefore, by making the thin metal wire W1 short, the inductance can be reduced, and the resistance of the thin metal wire W1 to external forces can be improved.

[0019] [size] The dimensions of this embodiment will be explained with reference to Figure 1, and the size of the present invention will be explained. The size of the internal space of sensor chamber 40 is selected so that the short side is about 10 to 15 mm and the long side is about 10 to 20 mm in plan view. In FIG. 5, since there are two rows of printed circuit boards 30, the size of the internal space of sensor chamber 40 is about twice that of FIG. 1, with the short side being about 35 mm and the long side being about 40 mm. As shown in FIG. 5, the size varies depending on how many printed circuit boards 30 are used and the number of rows. The height of sensor chamber 40 from the surface of sensor substrate 102 or odor detection element to the ceiling is approximately 2 mm to 4 mm. The thickness of both chips is 210 μm, the wire length is approximately 300 μm, the chip spacing is 200 μm, the IC chip planar size is 1000 μm x 500 μm, and the odor sensor planar size is 800 μm x 600 μm. Furthermore, the pump described below can control the flow rate between 0.3 liters / minute and 1 liter / minute with the applied voltage, and typically uses a flow rate between 0.5 liters / minute and 1 liter / minute. A specific embodiment, that is, mounting on a housing, will be described below with reference to FIGS.

[0020] [Configuration of odor measurement device] The sensor device 100 has a housing 101, and an odor sensor module 103 is provided inside the housing 101. The odor sensor module 103 is composed of a sensor substrate 102, a semiconductor integrated circuit 201 mounted on the sensor substrate 102, two odor detection elements 203, a temperature and humidity sensor 104, and the like. 1 shows one odor sensor module 103, but here it is made up of four odor sensor modules 103. These are for the purpose of detecting odors, and four types of sensitive films are provided separately. The sensor board 102 here also includes a board on which a temperature and humidity sensor is mounted, making it made up of a total of five boards. Below the sensor substrate 102 is a mounting substrate 105, which is a motherboard. A sensor control circuit 106 and a power supply circuit 107 are mounted on the mounting substrate, and lead pins 108 that connect the sensor substrate 102 and the mounting substrate 105 are provided. Furthermore, a first pump 109, a second pump 110, and a pump control circuit 111 located above the housing 101 are provided.

[0021] Two flow paths are formed in the housing 101 to allow gas to flow in and be discharged to the outside after passing through the surface of the odor sensor module 103. The outsides of these flow paths serve as an inlet and an outlet. 5, housing 101 is made up of a plurality of members, and here it is made up of three parts: first housing 131, second housing 132, and third housing 133. These are joined (fitted) together with screws 134. First housing 131 is a lid that forms the upper wall of the internal space that is the sensor chamber. Second housing 132 has sensor board 102 attached thereto, and sensor board 102 and the inner wall of first housing 131 form internal space 141. Furthermore, third housing 133 forms a storage space for first pump 109. First housing 131 and second housing 132 form an internal space 141. A packing (not shown) is disposed between the housings. 5 shows second housing 132 viewed from above with first housing 131 and third housing 133 removed, and the mounted sensor board 102 is visible.

[0022] As shown in FIG. 5, the housing 101 is provided with a first flow path 151, a second flow path 152, and a third flow path 153. First flow path 151 is provided from top to bottom in first housing 131 and third housing 133, and connects internal space 141 with the outside. First pump 109 is arranged midway along first flow path 151. Second flow path 152 is provided in first housing 131 and third housing 133, and connects internal space 141 with the outside. Second pump 110 is disposed midway along second flow path 152. The parts indicated by the reference numerals 151 and 152 in FIG. 4 are the two inlets. Third flow path 153 is provided in the side wall of first housing 131, and connects internal space 141 with the outside of housing 101. The outside of third flow path 153 is an outlet.

[0023] The sensor substrate 102 is a printed circuit board made of a resin material having a conductive pattern such as wiring, and is equipped with an odor sensor module 103 and a temperature and humidity sensor 104. The sensor substrate 102 is a so-called printed circuit board, and may be a ceramic substrate or the like.

[0024] 7, the sensor substrate 102 is mounted on a mounting substrate 105 by lead pins 108. A sensor control circuit 106 processes the output signal of the odor sensor module 103 and communicates with the outside. A power supply circuit 107 supplies driving power to a first pump 109 and a second pump 110.

[0025] Lead pins 108 are disposed between mounting substrate 105 and sensor substrate 102, separating sensor substrate 102 from mounting substrate 105, and supporting sensor substrate 102 relative to mounting substrate 105. When mounting substrate 105 is joined to second housing 132, internal space 141 is sealed by first housing 131, second housing 132, and mounting substrate 105, which form a lid. Furthermore, the sensor substrate 102 is separated from the mounting substrate 105 by the lead pins 108 , and the internal space 141 is divided into a flow path space 144 and a non-flow path space 145 .

[0026] First pump 109 is disposed in first flow path 151 and sends the gas to be measured to flow path space 144. First pump 109 may also be disposed outside first flow path 151. The gas flows from the outside into flow path space 144 via first flow path 151 and is discharged from third flow path 153. The gas sending direction of first pump 109 may also be reversed.

[0027] The second pump 110 is disposed in the second flow path 152 and delivers the cleaning gas to the flow path space 144. Alternatively, the second pump 110 may be disposed outside the second flow path 152. The cleaning gas flows from the outside into the flow path space 144 via the second flow path 152 and is discharged from the third flow path 153.

[0028] As described above, the odor sensor device 100 is provided with a separate cleaning mechanism, but the second pump 110 and the second flow path 152 may be omitted, and the first pump 109 and the first flow path 151 may be used for both cleaning and measurement. In other words, after measuring odor substances, cleaning can be performed by sucking in a cleaning gas with the first pump 109.

[0029] Pump control circuit 111 includes a circuit board 191 and a control element 192 mounted on circuit board 191, and controls first pump 109 and second pump 110. The configuration of pump control circuit 111 is not particularly limited.

[0030] [Operation of the odor measuring device] When odor measurement begins, the first pump 109 is driven, and odor substances contained in the gas are supplied to the surface of each odor sensor module 103 and detected by each odor sensor module 103. Before or after this odor measurement, cleaning of the flow path space 144 is performed. During cleaning, the second pump 110 is driven, and a cleaning gas flows through the flow path space 144. The cleaning gas not only takes in odor substances and moisture adsorbed on the adsorption film and releases them to the outside, but also cleans odor substances adsorbed on the inner walls of the flow path space 144, etc.

[0031] [Configuration of the odor sensor module] As explained with reference to FIGS. 1 to 3, odor sensor module 103 includes semiconductor integrated circuit 201, first odor detection element 202, second odor detection element 203, first thin metal wire 204, and second thin metal wire 205. As shown in Figure 6, semiconductor integrated circuit 201 is rectangular in plan view, with connection pads 215 and 216 for connecting to FBARs provided on its short sides 211 and 212. Oscillator circuits are built into each of the two short sides of semiconductor integrated circuit 201, with a counter circuit provided between them, so the distance between the oscillator circuits is set long. This prevents mutual interference and suppresses oscillation halts due to noise intrusion. Furthermore, the inductance generated by the FBAR's thin metal wire connection is also affected.

[0032] As mentioned above, the oscillation circuit in the semiconductor integrated circuit 201, including the FBAR, oscillates. Therefore, the inductance of the electrically connecting thin metal wires 204 and 205 has an effect. Therefore, to make the oscillation characteristics of the two oscillation circuits the same and prevent oscillation from stopping, it is preferable to make the lengths of the thin metal wires as short as possible, and even to make them substantially the same length. For this reason, it is important to make the chip thickness of the odor detection elements 202 and 203 the same as the chip thickness of the semiconductor integrated circuit 201. By making them the same thickness, the loop length of the thin metal wire can be minimized. Semiconductor chips include ICs and discrete chips, and the thickness of these chips varies from company to company. Therefore, it is important to grind down at least one of the chips to make the thickness of the three chips the same. Furthermore, because this thin metal wire is exposed to the flow path, making it as short as possible increases its strength, which has the advantage of reducing corrosion and mechanical damage. Furthermore, by extending the thin metal wires 204 and 205 in the direction along the gas flow, similar to the thin metal wire W1 in FIG. 1, the influence of the air flow can be suppressed and measurement accuracy can be improved. [Explanation of symbols]

[0033] 10A, 10B: Odor detection element 20:Semiconductor integrated circuit 21,22: Short side 30: Printed circuit board 40: Sensor room 60: Entrance 61: Outlet W1: Fine metal wire 100: Odor sensor device 101: Cabinet 102: Sensor board 103: Odor sensor module 104: Temperature and humidity sensor 105: Mounting board 106: Sensor control circuit 107: Power supply circuit 108: Lead pin 109: First pump 110: Second pump 111: Pump control circuit 201: Semiconductor integrated circuit 202, 203: Odor detection element 204, 205: Fine metal wire

Claims

1. a semiconductor integrated circuit mounted on a printed circuit board, the semiconductor integrated circuit having a first circuit formed on one of opposing sides and a second circuit formed on the other of opposing sides; a first odor detection element that is mounted on the printed circuit board, arranged close to one side of the semiconductor integrated circuit, and oscillated by the first circuit; a second odor detection element mounted on the printed circuit board, arranged adjacent to the other side of the semiconductor integrated circuit, and oscillated by the second circuit; The semiconductor integrated circuit, the first odor detection element, and the second odor detection element are disposed in a flow path through which a gas passes, and are aligned along the direction of the gas flow. Odor sensor module.

2. 2. The odor sensor module according to claim 1, wherein the semiconductor integrated circuit, the first odor detection element, and the second odor detection element have the same thickness.

3. the semiconductor integrated circuit is rectangular in plan view, 3. The odor sensor module according to claim 1, wherein the one side and the other side are short sides of the semiconductor integrated circuit, and the long side of the semiconductor integrated circuit is parallel to the direction of the gas flow.

4. 3. The odor sensor module according to claim 1, wherein the semiconductor integrated circuit has a counter circuit provided between the first circuit and the second circuit, the counter circuit counting the frequencies of the first circuit and the second circuit.

5. a first thin metal wire electrically connecting the semiconductor integrated circuit and the first odor detection element; a second thin metal wire electrically connecting the semiconductor integrated circuit and the second odor detection element; 3. The odor sensor module according to claim 1, further comprising:

6. The odor sensor module according to claim 5 , wherein the first thin metal wire and the second thin metal wire are provided along the direction of the gas flow.

7. 4. The odor sensor module according to claim 3, wherein components are mounted only on the surface of the printed circuit board in an area outside the long sides.

8. The odor sensor module according to claim 1 is provided in a sensor chamber that forms the flow path, and the flow path is provided with an inlet and an outlet, A gas transfer device is provided at the inlet or outlet. Odor sensor device.

9. 9. The odor sensor device according to claim 8, wherein the gas transfer device is a pump, and the pressure in the sensor chamber changes between positive and negative pressures.

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