JP2009258092A - Concentration sensor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a concentration sensor device, reducing foreign matter adhering to a sensor part, and detecting alcohol concentration with a high degree of precision. <P>SOLUTION: A piezoelectric element part 13 is provided on a substrate 11 on the side opposite to the sensor part 12. Therefore, a vibration area of the piezoelectric element part 13 is secured without hampering the arrangement of the sensor part 12 and the piezoelectric element 13. When electricity makes the piezoelectric element 13 vibrate, the substrate 11 and the sensor part 12, which are integrated with the piezoelectric element part 13 are also vibrated. Thus, the foreign matter in a mixed fuel adhering to the sensor part 12 exposed to the mixed fuel is accelerated to separate from the sensor part 12 by the vibration of the sensor part 12 caused by the vibration of the piezoelectric element part 13. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a concentration sensor device, and more particularly to a concentration sensor device that detects a mixing ratio of a specific component contained in a liquid.

  Conventionally, concentration sensor devices that detect the concentrations of specific components contained in various liquids have been widely used. For example, in recent years, the use of alcohol-mixed fuels in which biological components such as alcohol are mixed with petroleum-derived gasoline or light oil has been attempted. The performance or control of the internal combustion engine varies depending on the mixing ratio of petroleum-derived components and biological components in the mixed fuel, that is, the alcohol concentration. Therefore, it is required to detect the alcohol concentration in the mixed fuel with high accuracy. As described above, it is required to detect the concentration of the specific component in the liquid with high accuracy in various fields as well as the alcohol mixed fuel. As an example of such a concentration sensor device, for example, Patent Document 1 that detects the alcohol concentration of a mixed fuel is known.

Japanese National Patent Publication No. 5-507561

  The sensor device disclosed in Patent Literature 1 includes a casing that forms a passage through which fuel flows and a sensor element that is provided in the casing. A sensor element exposed to the mixed fuel flowing through the passage detects alcohol concentration by directly touching the fuel. However, in the case of Patent Document 1, the flow path formed by the casing forms a complex maze shape, and a large sensor element is provided in the complex flow path. For this reason, foreign matters contained in a liquid such as fuel, that is, solid matter or bubbles, are likely to adhere to the detection portion of the sensor element. As a result, there is a problem that the detection accuracy of the concentration of the specific component contained in the liquid is reduced as the foreign matter adheres.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a concentration sensor device that reduces the adhesion of foreign matter to the sensor unit and has high detection accuracy of characteristic components contained in liquid. There is.

In the first aspect of the invention, the deposition limiting portion is provided. The accumulation limiting unit prevents foreign matter from accumulating on the sensor unit. The deposition limiting unit is integrated with the sensor unit or provided upstream of the sensor unit in the liquid flow direction. As a result, the foreign matter contained in the liquid is prevented from adhering to and depositing on the sensor unit by the deposition limiting unit. Accordingly, the accumulation of foreign matter on the sensor unit is hindered, and the detection accuracy of the concentration of the characteristic component contained in the liquid can be increased.
In the invention described in claim 2, the deposition limiting portion has a piezoelectric element. The piezoelectric element vibrates when energized. Therefore, even if foreign matter adheres to the sensor unit, the attached foreign matter is promoted to be detached from the sensor unit due to vibration of the piezoelectric element. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

According to a third aspect of the present invention, the piezoelectric element is provided on the surface opposite to the sensor portion with the substrate interposed therebetween. Therefore, the piezoelectric element is widely provided on the surface of the substrate opposite to the sensor unit without being obstructed by the sensor unit. Therefore, the vibration area of the piezoelectric element can be ensured without increasing the size. Further, the sensor unit and the piezoelectric element can be formed separately and independently. Therefore, the manufacturing process can be simplified.
In the invention according to claim 4 or claim 10, the circuit portion provided on the sensor portion side and the piezoelectric element are connected by a through electrode penetrating the substrate. Therefore, the through electrode is not exposed to the outside of the substrate. Thereby, the contact between the through electrode and the mixed fuel is reduced. As a result, for example, corrosion and damage of the member forming the through electrode due to moisture contained in the mixed fuel is reduced. Therefore, durability of the through electrode can be increased.

In the invention according to claim 5, the piezoelectric element is provided on the same surface as the sensor portion on the substrate. Therefore, although it is difficult to ensure the vibration area of the piezoelectric element, it is possible to arrange the piezoelectric element close to the sensor unit. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.
In the invention of claim 6, the piezoelectric element is provided between the substrate and the sensor portion. Thereby, a piezoelectric element is provided in a wide area, without being disturbed by a sensor part. Further, the piezoelectric element and the sensor unit are arranged close to each other. Accordingly, the vibration area of the piezoelectric element can be ensured without increasing the size, and the detachment of the foreign matter attached to the sensor unit can be promoted.

The invention according to claim 7 further includes a recess. That is, the substrate forms a diaphragm-shaped recess. Therefore, the vibration of the sensor unit is promoted by the piezoelectric element provided around the recess. Accordingly, it is possible to further promote the detachment of the foreign matter attached to the sensor unit.
According to the eighth aspect of the present invention, the piezoelectric element is provided along the concave portion on the opposite surface on which the sensor portion is provided. For this reason, the entire substrate on which the diaphragm-shaped recess is formed vibrates by the piezoelectric element. Accordingly, it is possible to further promote the detachment of the foreign matter attached to the sensor unit.

In the invention described in claim 9, the opening side of the substrate on which the recess is formed is covered with an insulating film. The piezoelectric element is provided on the opposite side of the insulating film from the substrate. Therefore, the piezoelectric element vibrates the insulating film. The vibration of the insulating film by the piezoelectric element causes the substrate to vibrate via the recess. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.
In the invention described in claim 11, the opening side of the substrate on which the recess is formed is covered with an insulating film. The sensor part and the piezoelectric element are provided on this insulating film. That is, the sensor unit and the piezoelectric element are provided on the same surface side of the insulating film. Therefore, when the piezoelectric element vibrates the insulating film, the sensor unit provided in the insulating film also vibrates. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

  In the invention described in claim 12, the opening side of the substrate in which the recess is formed is covered with an insulating film. An insulator is laminated on the opposite side of the insulating film from the substrate. The piezoelectric element is provided on the opposite side of the recess with the insulating film interposed therebetween, and the sensor unit is provided at a position facing the piezoelectric element with the insulator interposed therebetween. When the piezoelectric element vibrates, the vibration is transmitted to the insulating film and the insulator. That is, the piezoelectric element vibrates not only the insulating film but also the insulator. Thereby, the sensor part provided in the insulator also vibrates. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

  In the invention described in claim 13, gas is sealed in the space formed between the substrate and the insulating film by the recess. For example, the piezoelectric element and the gas sealed in the space resonate by adjusting the kind pressure of the gas sealed in the space. Thereby, the vibration of the piezoelectric element is more effectively transmitted to the sensor unit side. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

In the invention described in claim 14, the comb-shaped electrode pattern of the sensor portion constitutes a piezoelectric element portion. That is, the electrode pattern is both a sensor part and a piezoelectric element part. Therefore, the sensor unit can be self-cleaned by its own vibration.
According to the fifteenth aspect of the present invention, the electrode portion is provided on the surface opposite to the sensor portion with the substrate interposed therebetween. Thereby, by applying a potential difference between the electrode pattern of the piezoelectric element constituting the sensor unit and the electrode unit, the electrode pattern, that is, the sensor unit itself vibrates with the vibration of the substrate. Therefore, the sensor unit can be self-cleaned by its own vibration.

In the invention described in claim 16, the piezoelectric element portion has an electrode pattern laminated on the side opposite to the substrate of the sensor portion. That is, the sensor part is covered with the electrode pattern of the piezoelectric element part on the side opposite to the substrate. Therefore, the sensor unit also vibrates due to the vibration of the electrode pattern of the piezoelectric element unit. Therefore, the sensor unit can be self-cleaned by its own vibration.
In the seventeenth aspect of the invention, the piezoelectric element portion has an electrode pattern on the surface opposite to the sensor portion across the substrate. That is, the electrode pattern of the piezoelectric element portion is formed on the surface opposite to the sensor portion of the substrate. Therefore, the vibration of the piezoelectric element part is transmitted to the sensor part via the substrate. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted.

  In the invention described in claim 18, the piezoelectric element portion has a first electrode pattern constituting the sensor portion and a second electrode pattern provided on a surface opposite to the sensor portion across the substrate. . Therefore, the sensor unit vibrates itself due to the vibration of the first electrode pattern and also vibrates due to the vibration of the second electrode pattern transmitted through the substrate. Accordingly, it is possible to promote the detachment of the foreign matter adhering to the sensor unit and to self-clean the sensor unit by its own vibration.

  In the invention according to claim 19, the piezoelectric element portion includes a first electrode pattern laminated on the side opposite to the substrate of the sensor portion, and a second electrode pattern provided on the surface opposite to the sensor portion across the substrate. And have. Therefore, the sensor unit vibrates with the vibration of the first electrode pattern, and also vibrates due to the vibration of the second electrode pattern transmitted through the substrate. Accordingly, the detachment of the foreign matter attached to the sensor unit can be promoted, and self-cleaning can be performed by the vibration of the sensor unit itself.

  According to a twentieth aspect of the present invention, the deposition restricting portion housed in the liquid passage formed by the passage forming portion has a charging portion and a capturing portion that are separate from the sensor portion. The liquid flowing through the liquid passage is charged by applying a voltage at the charging unit. The foreign substance contained in the liquid is charged together with the liquid. Therefore, when the liquid passes through the capturing unit, the charged foreign matter contained in the liquid is captured by the capturing unit before reaching the sensor unit. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

  In the invention described in claim 21, the liquid passage is provided with a wall portion. The wall part separates the flow of the liquid that has passed through the charging part into the sensor part side and the capturing part side. Foreign matter contained in the liquid charged by the charging unit is likely to move to the capturing unit side. Therefore, by separating the liquid flow into the capturing part side and the sensor part side by the wall part, it becomes difficult for foreign matter contained in the liquid to flow into the sensor part side. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are further reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

  In the invention described in claim 22, the deposition limiting portion has a charge removal portion on the downstream side of the sensor portion. Thereby, the liquid charged by the charging unit and the capturing unit is neutralized by the neutralizing unit. By charging the liquid with charge in the charging unit and the capturing unit, there is a possibility that the device or apparatus provided on the downstream side of the sensor unit may be affected. Therefore, the static elimination unit neutralizes the charge of the liquid that has passed through the sensor unit. As a result, the charged liquid does not affect the device or apparatus provided on the downstream side of the sensor unit. Therefore, the influence on the outside can be reduced.

  In the invention as set forth in claim 23, the voltage applied to the charging unit and the voltage applied to the capturing unit are different in polarity (positive (+) or negative (-)). For example, when a positive voltage is applied at the charging unit, a negative voltage is applied at the capturing unit. In both the charging unit and the capturing unit, one polarity is maintained without being inverted from one polarity to the other polarity. That is, when a positive voltage is applied by the charging unit, the charging unit always maintains a positive voltage, and the capturing unit maintains a negative voltage. Thereby, the foreign material charged by the charging unit is reliably captured by the capturing unit, and movement to the sensor unit side is limited. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

  In a twenty-fourth aspect of the invention, the voltage applied to the liquid at the charging unit and the capturing unit is an alternating voltage of 1 kHz or more. In this voltage, the maximum value on the negative side and the minimum value on the positive side are set to the ground voltage. When a direct current voltage or a low frequency alternating current is applied to the liquid, the liquid and various components contained in the liquid may cause an electrochemical reaction. Therefore, an alternating voltage of 1 kHz or higher is applied to the charging unit and the capturing unit so that the liquid does not cause irreversible chemical changes. Therefore, the change of the liquid can be reduced and the influence on the outside can be reduced.

  In the invention described in claim 25, the capturing part has at least one plate-like electrode member. The plate-like electrode member extends in parallel with the axis of the liquid passage, and has a plate width corresponding to a chord at an arbitrary position in a cross section perpendicular to the axis of the liquid passage. That is, the electrode member has a plate width that reaches the other end side from one end of the passage forming member that forms the liquid passage on the upstream side of the liquid passage. The electrode member has a reduced plate width toward the downstream side. That is, the electrode member has a larger plate width toward the charging unit side and a smaller plate width toward the sensor unit side. Thereby, foreign matters are effectively removed from the liquid that has passed through the charging portion on the upstream side having a large plate width. Further, the electrode member extends in parallel with the liquid passage, whereby the pressure loss of the liquid flowing through the liquid passage is reduced. Accordingly, foreign matter contained in the liquid can be captured upstream of the sensor unit while reducing the pressure loss of the liquid, and the concentration detection accuracy of the sensor unit can be increased.

  In the invention of claim 26, the capturing part has at least one plate-like electrode member. The plate-like electrode member extends while being inclined with respect to the axis of the liquid passage. The electrode member narrows at least a part of the width of the liquid passage from the upstream side to the downstream side of the liquid passage. Therefore, the liquid flowing through the liquid passage flows between the electrode members that are gradually narrowed. Thereby, the foreign material contained in the liquid is easily captured by the capturing unit. Therefore, the foreign substance contained in the liquid can be captured upstream of the sensor unit, and the concentration detection accuracy of the sensor unit can be increased.

  According to a twenty-seventh aspect of the present invention, the capturing part has at least one cylindrical and conical electrode member. That is, the capturing part has, for example, a conical or pyramidal electrode member. The electrode member has an inner diameter that decreases from the upstream side toward the downstream side. Therefore, the liquid passes through the electrode member whose inner diameter gradually decreases. Thereby, the foreign material contained in the liquid is easily captured by the capturing unit. Therefore, the foreign substance contained in the liquid can be captured upstream of the sensor unit, and the concentration detection accuracy of the sensor unit can be increased.

  In the invention of claim 28, the capturing part has at least one cylindrical and cone-shaped electrode member. That is, the capturing part has, for example, a conical or pyramidal electrode member. And this electrode member is a shape which guides the flow of the liquid in a liquid passage toward the inner wall side of a channel | path formation member toward the downstream from the upstream. Therefore, the liquid passes through the electrode member that gradually approaches the inner wall of the passage forming member. Thereby, the foreign matter contained in the liquid is easily captured by the capturing unit, and the pressure loss of the liquid is relatively small. Therefore, the foreign substance contained in the liquid can be captured upstream of the sensor unit, and the concentration detection accuracy of the sensor unit can be increased.

  According to a twenty-ninth aspect of the present invention, there is provided vibration imparting means for imparting vibration to the passage forming member. The charging unit and the capturing unit provided in the liquid passage may accumulate foreign matter when used for a long period of time. Therefore, by intermittently vibrating the passage forming member that forms the liquid passage by the vibration applying means, the charging unit and the capturing unit also vibrate together with the passage forming member. Therefore, it is possible to reduce the accumulation of foreign matters on the charging unit and the capturing unit.

  In a thirty-third aspect of the present invention, a protective film portion that covers the sensor portion is provided. The protective film part has a deposition limiting part at the end opposite to the sensor part. In other words, the sensor unit integrally has a deposition limiting unit. Thereby, the accumulation of foreign matter on the sensor unit and the protective film unit covering the sensor unit is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

In the invention according to claim 31 or 32, the protective film portion is formed to have a rough surface or a convex surface on the side opposite to the sensor portion. Therefore, the adhesion of foreign matter to the protective film portion is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.
In a thirty-third aspect of the invention, the protective film portion has a flow path forming portion. The flow path forming part forms a liquid flow on the surface of the protective film part. Thereby, the foreign material adhering to the protective film part is removed by the flow of the liquid. Therefore, the adhesion of foreign matter to the protective film portion is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.

In the invention of claim 34, the protective film portion is a porous member. The pores of the porous member restrict the passage of foreign substances while allowing the flow of liquid. For this reason, the foreign matter accumulates on the porous member and does not adhere to the sensor unit. Therefore, the adhesion and accumulation of foreign matter on the sensor unit are reduced, and the detection accuracy of the specific component contained in the liquid can be increased.
According to a thirty-fifth aspect of the invention, there is provided vibration imparting means for imparting vibration to the porous member. By using the porous member, foreign substances contained in the liquid are deposited on the surface of the porous member. Therefore, the removal of the foreign matter deposited on the porous member can be promoted by vibrating the porous member with the vibration applying means.

Sectional drawing which shows the outline of the density | concentration sensor apparatus by 1st Embodiment of this invention. Schematic diagram showing the attachment state of the concentration sensor device to the piping member Sectional drawing which shows the outline of the density | concentration sensor apparatus by 2nd Embodiment of this invention. Sectional drawing which shows the outline of the density | concentration sensor apparatus by 3rd Embodiment of this invention. Sectional drawing which shows the outline of the density | concentration sensor apparatus by 4th Embodiment of this invention. Sectional drawing which shows the outline of the density | concentration sensor apparatus by 5th Embodiment of this invention. Sectional drawing which shows the outline of the density | concentration sensor apparatus by 6th Embodiment of this invention. Sectional drawing which shows the outline of the density | concentration sensor apparatus by 7th Embodiment of this invention. Sectional drawing which shows the outline of the density | concentration sensor apparatus by 8th Embodiment of this invention. It is the schematic which shows the density | concentration sensor apparatus by 9th Embodiment of this invention, (A) is a top view, (B) is sectional drawing in the AA of (A). The figure equivalent to FIG.10 (B) which shows the density | concentration sensor apparatus by 10th Embodiment of this invention. It is the schematic which shows the density | concentration sensor apparatus by 11th Embodiment of this invention, (A) is a top view, (B) is sectional drawing in the AA of (A). It is the schematic which shows the density | concentration sensor apparatus by 12th Embodiment of this invention, (A) is a figure equivalent to FIG.10 (B), (B) is an arrow line view from the arrow B direction of (A). The schematic diagram which shows the attachment state to the piping member of the density | concentration sensor apparatus by 13th Embodiment of this invention. Schematic diagram showing a concentration sensor device according to a fourteenth embodiment of the present invention. The schematic diagram which shows the change of the voltage applied to a charging part and a capture part in 14th Embodiment The schematic diagram which shows the density | concentration sensor apparatus by 15th Embodiment of this invention. (A) is a sectional view taken along line AA in FIG. 17, and (B) is a sectional view taken along line BB in FIG. The schematic diagram which shows the density | concentration sensor apparatus by 15th Embodiment of this invention. (A) is a schematic diagram showing a concentration sensor device according to a sixteenth embodiment of the present invention, (B) is a sectional view taken along line BB of (A). The schematic diagram which shows the density | concentration sensor apparatus by 16th Embodiment of this invention. The schematic diagram which shows the density | concentration sensor apparatus by 17th Embodiment of this invention. The schematic diagram which shows the density | concentration sensor apparatus by 17th Embodiment of this invention. Schematic diagram showing a concentration sensor device according to an eighteenth embodiment of the present invention. Schematic diagram showing a concentration sensor device according to an eighteenth embodiment of the present invention. The schematic diagram which shows the density | concentration sensor apparatus by 19th Embodiment of this invention. The schematic diagram which shows the density | concentration sensor apparatus by 19th Embodiment of this invention. Schematic diagram showing a concentration sensor device according to a twentieth embodiment of the present invention. Schematic diagram showing a concentration sensor device according to a twentieth embodiment of the present invention. Schematic diagram showing a concentration sensor device according to a twenty-first embodiment of the present invention. (A) is a schematic diagram showing a cross section of a concentration sensor device according to a twenty-second embodiment of the present invention, and (B) is an arrow view from the direction of arrow A in (A). The figure equivalent to FIG. 31 (A) which shows the density | concentration sensor apparatus by 23rd Embodiment of this invention. The figure equivalent to FIG. 31 (A) which shows the density | concentration sensor apparatus by 24th Embodiment of this invention. The figure equivalent to FIG. 31 (A) which shows the density | concentration sensor apparatus by 25th Embodiment of this invention. An arrow view from the direction of arrow A in FIG. The figure equivalent to FIG. 35 which shows the modification of the density | concentration sensor apparatus by 25th Embodiment of this invention. The figure equivalent to FIG. 31 (A) of the density | concentration sensor apparatus by 26th Embodiment of this invention. The figure equivalent to FIG. 35 which shows the modification of the density | concentration sensor apparatus by 26th Embodiment of this invention.

  Hereinafter, a plurality of embodiments of a concentration sensor device will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same components are denoted by the same reference numerals, and description thereof is omitted. The concentration sensor device described below applies, for example, a mixed fuel as a liquid, and detects the concentration of a biological alcohol that is a specific component contained in the mixed fuel.

(First embodiment)
The concentration sensor device according to the first embodiment is shown in FIG. The concentration sensor device 10 according to the first embodiment includes a substrate 11, a sensor unit 12, and a piezoelectric element unit 13 as shown in FIG. 1. The substrate 11 is made of a semiconductor such as silicon, for example. The concentration sensor device 10 is attached to a piping member 100 through which a mixed fuel flows as shown in FIG. The concentration sensor device 10 is provided inside the piping member 100 at the top as shown in FIG. 2 (A), at the bottom as shown in FIG. 2 (B), or at the side as shown in FIG. 2 (C). It is done.

  As shown in FIG. 1, the sensor unit 12 is provided on one surface side of the substrate 11. An insulating film 14 is formed between the sensor unit 12 and the substrate 11. The insulating film 14 is, for example, a silicon oxide film. The sensor unit 12 has a plurality of electrodes 15. For example, the dielectric constant and relative dielectric constant between the electrodes 15 of the sensor unit 12 vary depending on the concentration of alcohol contained in the mixed fuel. The sensor unit 12 detects the dielectric constant or relative dielectric constant between the electrodes 15 to detect the concentration of alcohol contained in the mixed fuel, that is, the mixing ratio of petroleum-derived fuel and biological fuel. The sensor unit 12 is the same as a known configuration, and detailed description thereof is omitted. The sensor unit 12 is protected by a protective film 16. The protective film 16 is made of, for example, a silicon nitride film. The sensor unit 12 may not only detect the concentration using the dielectric constant or the relative dielectric constant, but may also electrically detect the concentration based on, for example, the capacitance or impedance between the electrodes 15. Further, the concentration of the specific component contained in the liquid may be optically detected from, for example, the refractive index of light or the transmittance of light having a specific wavelength. In the present disclosure, a case where the sensor unit 12 detects the concentration of a specific component contained in the liquid based on the dielectric constant between the electrodes 15 will be described.

The piezoelectric element portion 13 is provided on the surface of the substrate 11 opposite to the sensor portion 12. An insulating film 17 is formed between the piezoelectric element portion 13 and the substrate 11. The insulating film 17 is, for example, a silicon oxide film. The piezoelectric element section 13 has a structure in which a piezoelectric body (not shown) is sandwiched between electrodes, for example. The piezoelectric element portion 13 vibrates when energized.
The concentration sensor device 10 includes a circuit unit 18. The circuit unit 18 is provided on the same surface side as the sensor unit 12 in the substrate 11. The circuit unit 18 includes, for example, a processing circuit (not shown) and connection pads. The processing circuit constitutes a circuit that processes, for example, a signal output from the sensor unit 12 or a signal input to the piezoelectric element unit 13. The connection pad is connected to a bonding wire or the like that connects the concentration sensor device 10 to an external connection terminal. The circuit unit 18 is provided adjacent to the sensor unit 12 on the same surface side as the sensor unit 12. Similar to the sensor unit 12, the circuit unit 18 is protected by a protective film 16 made of a silicon nitride film.

  The piezoelectric element portion 13 is electrically connected to the circuit portion 18 by a through electrode 19 that penetrates the substrate 11. The piezoelectric element unit 13 vibrates based on a signal from the circuit unit 18. By connecting the piezoelectric element portion 13 and the circuit portion 18 with the through electrode 19, the through electrode 19 is not exposed to the outside of the substrate 11. As shown in FIG. 2 described above, the concentration sensor device 10 is provided inside the fuel passage 101 formed by the piping member 100. Therefore, the concentration sensor device 10 is exposed to the mixed fuel flowing through the fuel passage 101. A mixed fuel containing alcohol tends to contain a component that corrodes a metal such as water. As shown in FIG. 1, by providing the through electrode 19 inside the substrate 11, the through electrode 19 becomes difficult to come into contact with the fuel. As a result, even when exposed to the mixed fuel, the corrosion and wear of the through electrode 19 are reduced, and the durability of the through electrode 19 is improved.

  In the first embodiment, when the piezoelectric element unit 13 vibrates by energization, the substrate 11 and the sensor unit 12 integrated with the piezoelectric element unit 13 also vibrate. Thereby, the foreign matter in the mixed fuel adhering to the sensor unit 12 exposed to the mixed fuel is promoted to be detached from the sensor unit 12 by the vibration of the sensor unit 12 accompanying the vibration of the piezoelectric element unit 13. Therefore, the adhesion of foreign matter to the sensor unit 12 is reduced, and the detection accuracy of the alcohol concentration contained in the mixed fuel can be increased.

In the first embodiment, the piezoelectric element portion 13 is provided on the surface of the substrate 11 opposite to the sensor portion 12. Therefore, the sensor unit 12 does not hinder the arrangement of the piezoelectric element unit 13, and the piezoelectric element unit 13 does not hinder the arrangement of the sensor unit 12. As a result, a sufficient installation area of the piezoelectric element portion 13 is ensured. Therefore, the vibration area of the piezoelectric element portion 13 can be ensured without increasing the size of the physique. Furthermore, in the semiconductor device manufacturing process, the sensor unit 12 and the piezoelectric element unit 13 can be formed in separate and independent processes. Therefore, the manufacturing process can be simplified.
Furthermore, in the first embodiment, the through electrode 19 that connects the piezoelectric element portion 13 and the circuit portion 18 penetrates the substrate 11. Therefore, the through electrode 19 is not easily exposed to the mixed fuel containing moisture. Therefore, corrosion and damage of the through electrode 19 can be reduced, and durability of the through electrode 19 can be improved.

(Second and third embodiments)
The concentration sensor devices according to the second and third embodiments are shown in FIG. 3 and FIG. 4, respectively.
In the second embodiment, as shown in FIG. 3, the sensor unit 12 and the piezoelectric element unit 13 are provided on the same surface side of the substrate 11. When the sensor unit 12 and the piezoelectric element unit 13 are provided on the same surface side of the substrate 11, if the installation area of the sensor unit 12 and the piezoelectric element unit 13 is ensured, the size of the physique increases. The vibration area may be reduced. On the other hand, by providing the sensor unit 12 and the piezoelectric element unit 13 on the same surface side of the substrate 11, the sensor unit 12 and the piezoelectric element unit 13 are arranged close to each other. Therefore, the sensor unit 12 directly vibrates due to the vibration of the piezoelectric element unit 13, and the detachment of the foreign matter can be further promoted.

  In the third embodiment, as shown in FIG. 4, the concentration sensor device 10 includes an insulator layer 21 on one surface side of the substrate 11 with an insulating film 17 interposed therebetween. The insulating film 17 is formed of a silicon oxide film as described above, and the insulator layer 21 is formed of a silicon nitride film. The piezoelectric element portion 13 is provided on the surface of the insulating film 17 opposite to the substrate 11. The insulator layer 21 covers the piezoelectric element portion 13 provided on the insulating film 17. The sensor unit 12 is provided on the surface of the insulator layer 21 opposite to the substrate 11. With such a configuration, the piezoelectric element unit 13 is disposed between the substrate 11 and the sensor unit 12.

  In 3rd Embodiment, by providing the piezoelectric element part 13 between the board | substrate 11 and the sensor part 12, arrangement | positioning of the piezoelectric element part 13 and the sensor part 12 is not prevented mutually. Further, by providing the piezoelectric element portion 13 between the substrate 11 and the sensor portion 12, the sensor portion 12 and the piezoelectric element portion 13 are disposed close to each other. Therefore, although the formation process of the sensor unit 12 and the piezoelectric element unit 13 is complicated, it is possible to achieve both the securing of the vibration area by the piezoelectric element unit 13 and the close arrangement of the sensor unit 12 and the piezoelectric element unit 13. it can.

(Fourth embodiment)
FIG. 5 shows a concentration sensor device according to the fourth embodiment.
As shown in FIG. 5, the concentration sensor device 10 according to the fourth embodiment includes a recess 22 provided in the substrate 11. The recess 22 is formed in a diaphragm shape that is recessed from one surface side of the substrate 11 to the other surface side. The sensor unit 12 and the circuit unit 18 are provided on the flat side of the substrate 11, that is, the surface side opposite to the recess 22. The piezoelectric element portion 13 is provided along the end surface on the opening side of the recess 22. As a result, the piezoelectric element portion 13 is in a state of covering the opening side surface of the substrate 11 on which the recess 22 is formed. As a result, the piezoelectric element portion 13 is provided on the surface side opposite to the sensor portion 12 and the circuit portion 18 with the substrate 11 interposed therebetween.
The concentration sensor device 10 includes a through electrode 19 that penetrates the substrate 11 in the thickness direction. The through electrode 19 has one end connected to the circuit unit 18 and the other end connected to the piezoelectric element unit 13. As a result, the piezoelectric element portion 13 is electrically connected to the circuit portion 18 via the through electrode 19.

  In the fourth embodiment, by providing the piezoelectric element portion 13 along the recess 22, the distance between the piezoelectric element portion 13 and the sensor portion 12 is reduced. In addition to this, the substrate 11 is formed into a diaphragm shape by the concave portion 22, and the substrate 11 is vibrated by the piezoelectric element portion 13, whereby the vibration of the sensor portion 12 provided on the substrate 11 is further promoted. Therefore, the detachment of the foreign matter attached to the sensor unit 12 can be further promoted.

(Fifth embodiment)
FIG. 6 shows a concentration sensor device according to the fifth embodiment.
As shown in FIG. 6, the concentration sensor device 10 according to the fifth embodiment includes a recess 22 provided in the substrate 11. The recess 22 is formed in a diaphragm shape that is recessed from one surface side of the substrate 11 to the other surface side. The sensor unit 12 and the circuit unit 18 are provided on the flat side of the substrate 11, that is, the surface side opposite to the recess 22. In addition, the concentration sensor device 10 includes an insulating film 23 that closes the opening side of the substrate 11 provided with the recess 22. In other words, the recess 22 is closed at the opening end by the insulating film 23. The insulating film 23 is formed of, for example, a silicon oxide film.

  The piezoelectric element portion 13 is provided on the surface of the insulating film 23 opposite to the substrate 11. Thereby, the piezoelectric element part 13 is provided on the surface side opposite to the sensor part 12 and the circuit part 18 with the substrate 11 interposed therebetween. The piezoelectric element portion 13 is connected to the circuit portion 18 by a through electrode 19 that penetrates the substrate 11. By closing the opening side of the recess 22 with the insulating film 23, a space 24 is formed between the substrate 11 and the insulating film 23. The space 24 is filled with a gas such as nitrogen or air.

  In the fifth embodiment, a space 24 is formed between the substrate 11 and the insulating film 23 by closing the recess 22 provided in the substrate 11 with the insulating film 23. This space 24 is filled with a gas such as nitrogen or air. The natural frequency of the gas in the space 24 changes by adjusting the type, pressure, and amount of the gas filled in the space 24. Therefore, by approximating the natural frequency of the gas filled in the space 24 and the frequency of the piezoelectric element unit 13, the gas filled in the space 24 resonates with the piezoelectric element unit 13 and vibrates. As a result, the vibration of the piezoelectric element portion 13 is transmitted to the sensor portion 12 on the opposite side across the substrate 11 by the resonance of the gas filled in the space 24. Therefore, even when the substrate 11 is interposed between the piezoelectric element unit 13 and the sensor unit 12, the vibration of the sensor unit 12 can be promoted and the detachment of foreign matters from the sensor unit 12 can be promoted.

(6th, 7th, 8th embodiment)
The density sensor devices according to the sixth, seventh, and eighth embodiments are shown in FIGS. 7, 8, and 9, respectively.
In the sixth embodiment, as shown in FIG. 7, the sensor unit 12 and the piezoelectric element unit 13 are provided on the flat surface side of the substrate 11. That is, in the case of the sixth embodiment, the sensor unit 12 and the piezoelectric element unit 13 are provided on the same surface side of the substrate 11. An insulating film 25 made of a silicon oxide film is provided between the substrate 11 and the sensor unit 12 and the piezoelectric element unit 13. When the piezoelectric element portion 13 vibrates, the vibration is transmitted to the sensor portion 12 through the substrate 11 whose plate pressure is reduced by the concave portion 22. Therefore, the vibration of the sensor unit 12 is promoted, and the detachment of foreign matters can be promoted.

  In the seventh embodiment, as shown in FIG. 8, the sensor unit 12 and the piezoelectric element unit 13 are provided on the opposite side of the insulating film 26 made of a silicon oxide film that closes the recess 22 from the substrate 11. That is, also in the seventh embodiment, the sensor unit 12 and the piezoelectric element unit 13 are provided on the same surface side of the substrate 11. Thereby, when the piezoelectric element portion 13 vibrates, the vibration is transmitted to the sensor portion 12 through the vibration of the insulating film 26. Therefore, the vibration of the sensor unit 12 is promoted, and the detachment of foreign matters can be promoted.

  In the eighth embodiment, as shown in FIG. 9, an insulating layer 27 made of a silicon nitride film is provided on the opposite side of the insulating film 26 from the substrate 11. The sensor unit 12 is provided on the surface of the insulator layer 27 opposite to the substrate 11. The piezoelectric element portion 13 is provided on the opposite side of the insulating film 26 from the substrate 11. That is, the piezoelectric element unit 13 is provided between the substrate 11 and the sensor unit 12. Accordingly, when the piezoelectric element portion 13 vibrates, the vibration is transmitted to the sensor portion 12 through the insulating layer 27 laminated on the insulating film 26. Therefore, the vibration of the sensor unit 12 is promoted, and the detachment of foreign matters can be promoted.

(Ninth embodiment)
FIG. 10 shows a concentration sensor device according to the ninth embodiment.
In the ninth embodiment, the concentration sensor device 10 includes a substrate 11 and a sensor unit 12 as shown in FIG. As shown in FIG. 10B, the substrate 11 has an insulating film 14 on the end surface opposite to the sensor unit 12 and an insulating film 17 between the sensor unit 12. The sensor unit 12 has a plurality of electrode patterns 41 and 42 as shown in FIG. These electrode patterns 41 and 42 are each formed in a comb tooth shape facing each other. The sensor unit 12 detects the concentration of alcohol contained in the mixed fuel by detecting the dielectric constant and the relative dielectric constant between the opposing electrode pattern 41 and the electrode pattern 42. The electrode pattern 41 and the electrode pattern 42 of the sensor unit 12 are protected by the protective film 16.

In the case of the ninth embodiment, the two electrode patterns 41 and the electrode patterns 42 are both formed in a comb shape by a piezoelectric element. That is, both the electrode pattern 41 and the electrode pattern 42 are formed in a comb-teeth shape by depositing a piezoelectric material such as PZT and sputtering AgPd. The electrode pattern 41 and the electrode pattern 42 are electrically connected to a circuit unit (not shown). Thereby, a predetermined voltage is applied to the electrode pattern 41 and the electrode pattern 42 from the circuit unit. By applying a voltage between the electrode pattern 41 and the electrode pattern 42, distortion occurs between the electrode pattern 41 and the electrode pattern 42. By applying a voltage that generates a predetermined vibration pattern between the electrode pattern 41 and the electrode pattern 42 from the circuit unit, vibration along the sensor surface of the sensor unit 12 perpendicular to the plate thickness direction of the substrate 11 is generated. To do. That is, in the case of the ninth embodiment, the electrode pattern 41 and the electrode pattern 42 of the sensor unit 12 are the sensor unit 12 that measures the dielectric constant of the fuel and the piezoelectric element unit 13 that constitutes the deposition limiting unit.
The circuit unit measures the dielectric constant of the fuel and generates vibration due to energization of the sensor unit 12 in a time-sharing manner. That is, the circuit unit switches the application pattern of the voltage applied between the electrode pattern 41 and the electrode pattern 42 when measuring the dielectric constant of the fuel and when vibrating the sensor unit 12 as the piezoelectric element unit 13.

  In the ninth embodiment, the comb-shaped electrode patterns 41 and 42 constituting the sensor unit 12 are not only the sensor unit 12 but also the piezoelectric element unit 13. That is, the sensor unit 12 and the piezoelectric element unit 13 are integrally formed. Therefore, the sensor unit 12 can be self-cleaned by its own vibration, and the removal of foreign matter attached to the surface of the sensor unit 12 or the protective film 16 protecting the sensor unit 12 can be promoted. The surface of the protective film 16 is not only formed as a smooth surface, but may be formed as a rough surface in which the space between the electrode pattern 41 and the electrode pattern 42 is recessed. Thus, even when the surface of the protective film 16 is formed to be rough, the protective film 16 is distorted by the vibration between the electrode pattern 41 and the electrode pattern 42. As a result, foreign matter adhering to the concave portion of the rough surface can also be removed by the distortion of the protective film 16.

(10th Embodiment)
FIG. 11 shows a concentration sensor device according to the tenth embodiment. The tenth embodiment is a modification of the embodiment of FIG. 9, and the differences will be described.
In the tenth embodiment, as shown in FIG. 11, the concentration sensor device 10 includes an electrode portion 43 on the surface opposite to the sensor portion 12 with the substrate 11 interposed therebetween. The electrode part 43 is covered with the insulating film 14 together with the end face side opposite to the sensor part 12 of the substrate 11. The configurations of the electrode pattern 41 and the electrode pattern 42 constituting the sensor unit 12 are the same as those in the ninth embodiment.

  The electrode part 43 is electrically connected to a circuit part (not shown) together with the electrode pattern 41 and the electrode pattern 42. Therefore, a predetermined voltage is applied from the circuit portion between the electrode pattern 41 and the electrode pattern 42 and the electrode portion. By applying a voltage between the electrode pattern 41 and the electrode pattern 42 and the electrode portion 43, a dense wave in the thickness direction of the substrate 11 is generated between the electrode pattern 41 and the electrode pattern 42 and the electrode portion 43. . By applying a voltage that generates a predetermined vibration pattern from the circuit portion to the electrode pattern 41 and between the electrode pattern 42 and the electrode portion 43, vibration along the thickness direction of the substrate 11 is generated. For example, the circuit unit sets the polarity of the electrode unit 43 to negative (−), and arbitrarily switches the polarity of the electrode pattern 41 and the electrode pattern 42 to positive (+) or negative (−). As a result, vibration in the thickness direction of the substrate 11 occurs between the electrode pattern 41 and the electrode pattern 42 and the electrode portion 43.

  In the tenth embodiment, the electrode unit 43 is provided on the opposite side of the sensor unit 12 with the substrate 11 interposed therebetween. Thus, by applying a potential difference between the electrode patterns 41 and 42 of the piezoelectric elements constituting the sensor unit 12 and the electrode unit 43, the electrode patterns 41 and 42, that is, the sensor unit 12 itself vibrates including the substrate 11. Therefore, the sensor unit 12 can be self-cleaned by its own vibration. In addition, by changing the voltage application pattern to the electrode patterns 41 and 42 and the electrode portion 43, not only vibration along the sensor portion 12 between the electrode patterns 41 and 42, but also vibration in the plate thickness direction of the substrate 11. Can be generated in combination.

(Eleventh embodiment)
A concentration sensor device according to an eleventh embodiment is shown in FIG.
In the tenth embodiment, as shown in FIG. 12, the concentration sensor device 10 includes a substrate 11, a sensor unit 12, and a piezoelectric element unit 13. As shown in FIG. 12B, the substrate 11 has an insulating film 14 on the end surface opposite to the sensor unit 12 and an insulating film 17 between the sensor unit 12. The sensor unit 12 includes a plurality of electrodes 51 and 52 as shown in FIG. These electrodes 51 and 52 are formed so as to face each other. The electrode 51 and the electrode 52 are formed in, for example, a comb shape as shown in FIG. By detecting the dielectric constant and relative dielectric constant between the electrode 51 and the electrode 52, the sensor unit 12 detects the concentration of alcohol contained in the mixed fuel. The electrode 51 and the electrode 52 of the sensor unit 12 are protected by the protective film 16.

  In the case of the eleventh embodiment, the piezoelectric element portion 13 that is a deposition limiting portion is laminated on the opposite side of the protective film 16 that protects the sensor portion 12 from the substrate 11. Specifically, the piezoelectric element unit 13 includes an electrode pattern 53 and an electrode pattern 54 that are formed of piezoelectric elements. The electrode pattern 53 and the electrode pattern 54 are both formed on the side of the protective film 16 opposite to the substrate 11. Therefore, the electrode pattern 53 and the electrode pattern 54 constituting the piezoelectric element unit 13 are laminated on the protective film 16 that protects the sensor unit 12. Both the electrode pattern 53 and the electrode pattern 54 are protected by a protective film 55.

  Both the electrode pattern 53 and the electrode pattern 54 are formed in a comb-teeth shape with piezoelectric elements. The electrode pattern 53 and the electrode pattern 54 are electrically connected to a circuit unit (not shown). Thereby, a predetermined voltage is applied to the electrode pattern 53 and the electrode pattern 54 from the circuit unit. By applying a voltage between the electrode pattern 53 and the electrode pattern 54, distortion occurs between the electrode pattern 53 and the electrode pattern 54, and the sensor surface of the sensor unit 12 is perpendicular to the plate thickness direction of the substrate 11. Vibration along the line occurs.

  In the eleventh embodiment, the piezoelectric element unit 13 includes electrode patterns 53 and 54 stacked on the opposite side of the sensor unit 12 from the substrate 11. In other words, the sensor unit 12 is covered with the electrode patterns 53 and 54 of the piezoelectric element unit 13 on the side opposite to the substrate 11. Therefore, when vibration is generated by the electrode patterns 53 and 54 of the piezoelectric element unit 13, the sensor unit 12 also vibrates. Therefore, the sensor unit 12 can be self-cleaned by its own vibration.

(Twelfth embodiment)
A concentration sensor device according to the twelfth embodiment is shown in FIG.
In the twelfth embodiment, as shown in FIG. 13, the concentration sensor device 10 includes a substrate 11, a sensor unit 12, and a piezoelectric element unit 13. As shown in FIG. 13B, the substrate 11 has an insulating film 14 on the end surface opposite to the sensor unit 12 and an insulating film 17 between the sensor unit 12. The sensor unit 12 includes a plurality of electrodes 15 as shown in FIG. The electrode 15 has the same configuration as that of the first embodiment described above.

In the case of the twelfth embodiment, the piezoelectric element portion 13 is formed on the surface opposite to the sensor portion 12 with the substrate 11 interposed therebetween. Specifically, the piezoelectric element unit 13 constituting the deposition limiting unit has an electrode pattern 61 and an electrode pattern 62 formed of piezoelectric elements. The electrode pattern 61 and the electrode pattern 62 are both formed on the surface of the substrate 11 opposite to the sensor unit 12. Both the electrode pattern 61 and the electrode pattern 62 are protected by a protective film 63.
Each of the electrode pattern 61 and the electrode pattern 62 is a piezoelectric element and is formed in a comb shape. The electrode pattern 61 and the electrode pattern 62 are electrically connected to a circuit unit (not shown). Thereby, a predetermined voltage is applied to the electrode pattern 61 and the electrode pattern 62 from the circuit unit. By applying a voltage between the electrode pattern 61 and the electrode pattern 62, distortion occurs between the electrode pattern 61 and the electrode pattern 62. Therefore, the generated distortion becomes a dense wave and propagates through the substrate 11 in the thickness direction, causing the sensor unit 12 to vibrate.

  In the twelfth embodiment, the piezoelectric element portion 13 has electrode patterns 61 and 62 on the surface opposite to the sensor portion 12 with the substrate 11 interposed therebetween. That is, the substrate 11 has the electrode patterns 61 and 62 of the piezoelectric element portion 13 formed on the surface opposite to the sensor portion 12. Therefore, the vibration of the piezoelectric element unit 13 is transmitted to the sensor unit 12 via the substrate 11. Therefore, the detachment of the foreign matter attached to the sensor unit 12 can be promoted.

(Deformation)
The ninth embodiment and the twelfth embodiment described above may be combined. That is, in the concentration sensor device 10 according to the ninth embodiment, the sensor unit 12 having comb-shaped electrode patterns 41 and 42 corresponding to the first electrode pattern is provided on one end surface of the substrate 11, and the second end surface is provided with the second end surface. Comb-shaped electrode patterns 61 and 62 corresponding to the electrode patterns may be provided. Accordingly, the piezoelectric element unit 13 is configured by the electrode patterns 41 and 42 constituting the sensor unit 12 and the electrode patterns 61 and 62 provided on the opposite side of the substrate 11 from the sensor unit 12. Therefore, the sensor unit 12 vibrates itself due to the electrode patterns 41 and 42, and also vibrates due to the vibrations of the electrode patterns 61 and 62 transmitted via the substrate 11. As a result, the sensor unit 12 vibrates in a plurality of directions. Accordingly, it is possible to promote the detachment of the foreign matter attached to the sensor unit 12, and it is possible to self-clean the sensor unit 12 by its own vibration.

  Further, the eleventh embodiment and the twelfth embodiment may be combined. That is, in the concentration sensor device 10 according to the eleventh embodiment, comb-shaped electrode patterns 53 and 54 corresponding to the first electrode pattern are provided by being stacked with the sensor unit 12, and the end surface of the substrate 11 opposite to the sensor unit 12 is provided. Further, comb-shaped electrode patterns 61 and 62 corresponding to the second electrode pattern may be provided. As a result, the piezoelectric element unit 13 includes electrode patterns 53 and 54 that cover the sensor unit 12 and electrode patterns 61 and 62 that are provided on the opposite side of the substrate 11 from the sensor unit 12. Therefore, the sensor unit 12 vibrates itself due to the electrode patterns 53 and 54 and also vibrates due to the vibrations of the electrode patterns 61 and 62 transmitted through the substrate 11. As a result, the sensor unit 12 vibrates in a plurality of directions. Accordingly, it is possible to promote the detachment of the foreign matter attached to the sensor unit 12, and it is possible to self-clean the sensor unit 12 by its own vibration.

(13th Embodiment)
A concentration sensor device according to a thirteenth embodiment is shown in FIG.
In the case of the thirteenth embodiment, the concentration sensor device 10 may be provided in a piping member 100 that is partially cut away as shown in FIG. In this case, a mounting substrate 103 for attaching the concentration sensor device 10 is provided outside the piping member 100. A rib 31 and a seal member 32 are provided between the density sensor device 10 and the mounting substrate 103. Thereby, the inflow of the mixed fuel to the inside of the rib 31 and the seal member 32 is prevented. The mounting substrate 103 and the concentration sensor device 10 are electrically connected by, for example, solder balls 33 or bonding wires. In the case shown in FIG. 14, the piezoelectric element portion 13 of the concentration sensor device 10 is electrically directly connected to the mounting substrate 103 by, for example, solder balls 33 without passing through the circuit portion of the substrate 11. By providing the rib 31 and the seal member 32 between the concentration sensor device 10 and the mounting substrate 103, the inflow of the mixed fuel to the inside where the solder balls 33 and the bonding wires are provided is prevented. Therefore, corrosion and damage to the solder balls 33 and the bonding wires can be prevented.

(14th Embodiment)
A concentration sensor device according to a fourteenth embodiment is shown in FIG.
In the fourteenth embodiment, as shown in FIG. 15, the concentration sensor device 70 includes a passage forming member 71, a sensor unit 72, and a deposition limiting unit 73. The passage forming member 71 has a cylindrical shape and forms a fuel passage 74 as a liquid passage through which the mixed fuel flows. The mixed fuel flows through the fuel passage 74 from the left upstream side in FIG. 15 to the right downstream side. The sensor part 72 is comprised from the board | substrate which is not shown in figure like the some embodiment mentioned above, the electrode which is not shown in figure provided in this board | substrate, etc.

  The accumulation limiting unit 73 includes a charging unit 75 and a capturing unit 76 on the upstream side of the sensor unit 72 in the fuel flow direction in the fuel passage 74. The charging unit 75 applies a voltage to the mixed fuel flowing through the fuel passage 74. The charging unit 75 is formed in a net shape with, for example, a conductive metal. As a result, the charging unit 75 charges the mixed fuel flowing through the fuel passage 74. The capturing unit 76 is provided between the charging unit 75 and the sensor unit 72. That is, the capturing unit 76 is provided on the upstream side of the sensor unit 72 and on the downstream side of the charging unit 75. The capturing unit 76 captures foreign matter contained in the mixed fuel charged by the charging unit 75.

  As shown in FIG. 16, an AC voltage of 1 kHz or more is applied to the charging unit 75 and the capturing unit 76. The charging unit 75 and the capturing unit 76 have different polarities of applied voltages. For example, when the charging unit 75 is charged positive (+), the capturing unit 76 is charged negative (−). Further, when the charging unit 75 is positively charged, the charging unit 75 maintains a positive voltage without being inverted to a negative voltage. Similarly, when the capturing unit 76 is negatively charged, the capturing unit 76 maintains a negative voltage without being inverted to a negative voltage. As described above, the charging unit 75 and the capturing unit 76 maintain one of the positive and negative polarities. When the charging unit 75 is positively charged, the minimum value of the voltage is 0 V, which is the ground voltage. Similarly, when the capturing unit 76 is negatively charged, the maximum value of the voltage is 0V.

  As described above, in the fourteenth embodiment, the charging unit 75 and the capturing unit 76 having different polarities are provided on the upstream side of the sensor unit 72. As a result, the mixed fuel flowing through the fuel passage 74 is charged to a positive charge because a positive voltage is applied when passing through the charging unit 75. Therefore, the foreign matter contained in the mixed fuel is also charged with a positive charge. The mixed fuel containing the positively charged foreign matter passes through the charging unit 75 and then passes through the capturing unit 76. Since the capturing unit 76 is applied with a voltage having a polarity opposite to that of the charging unit, i.e., a negative voltage, foreign matter charged to a positive charge is captured by the capturing unit 76. As a result, the foreign matter contained in the mixed fuel is captured by the capturing unit 76 and the inflow to the sensor unit 72 is reduced.

  On the other hand, the mixed fuel passes through the charging unit 75 and the capturing unit 76 and is charged to a positive or negative charge. For this reason, the mixed fuel may electrically affect various devices (not shown) provided on the downstream side of the concentration sensor device 70. Therefore, the deposition limiting unit 73 has a static elimination unit 77 on the downstream side of the sensor unit 72 in the flow direction of the mixed fuel as shown in FIG. The static eliminating portion 77 is formed in a net shape with, for example, a conductive metal. For this reason, the charged mixed fuel passes through the charge removal unit 77, and thus the charge is removed and the charge is removed.

  In the fourteenth embodiment described above, the deposition restricting portion 73 housed in the fuel passage 74 formed by the passage forming member 71 has the charging portion 75 and the capturing portion 76 that are separate from the sensor portion 72. . The mixed fuel flowing through the fuel passage 74 is charged together with the foreign matter contained therein when a voltage is applied at the charging unit 75. Therefore, when the mixed fuel passes through the capturing unit 76, the foreign matter contained in the mixed fuel is captured before reaching the sensor unit 72. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 72 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.

  In the fourteenth embodiment, the deposition limiting unit 73 has a charge removal unit 77 on the downstream side of the sensor unit 72. As a result, the mixed fuel charged by the charging unit 75 and the capturing unit 76 is neutralized by the neutralization unit 77. By charging the mixed fuel with electric charge in the charging unit 75 and the capturing unit 76, there is a possibility of affecting devices and apparatuses provided on the downstream side of the sensor unit 72. Therefore, the static elimination unit 77 neutralizes the charge of the mixed fuel that has passed through the sensor unit 72. As a result, the charged mixed fuel does not affect the devices and apparatuses provided on the downstream side of the sensor unit 72. Therefore, the influence on the outside can be reduced.

  In the fourteenth embodiment, the voltage applied to the charging unit 75 and the voltage applied to the capturing unit 76 have different polarities. The charging unit 75 and the capturing unit 76 both maintain one polarity without being inverted from one polarity to the other. Thereby, the foreign material charged by the charging unit 75 is reliably captured by the capturing unit 76, and movement to the sensor unit 72 side is restricted. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 72 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.

In the fourteenth embodiment, the voltage applied to the mixed fuel by the charging unit 75 and the capturing unit 76 is an AC voltage of 1 kHz or more. In this voltage, the maximum value on the negative side and the minimum value on the positive side are set to the ground voltage. When a direct current voltage or a low frequency alternating current is applied to the mixed fuel, the mixed fuel and various components contained in the mixed fuel may cause an electrochemical reaction. Therefore, in the charging unit 75 and the capturing unit 76, an alternating voltage of 1 kHz or more is applied so that the mixed fuel does not cause irreversible chemical changes. Therefore, the change of the mixed fuel can be reduced and the influence on the outside can be reduced.
The charging unit 75 and the capturing unit 76 may have different polarities, and the charging unit 75 may be negatively charged and the capturing unit 76 may be positively charged.

(Fifteenth embodiment)
A concentration sensor device according to a fifteenth embodiment is shown in FIG.
In the fifteenth embodiment, as shown in FIG. 17, the capturing part 76 of the concentration sensor device 70 has an electrode member 81 that extends in parallel with the axis of the fuel passage 74. The electrode member 81 is formed in a plate shape, and at least one electrode member 81 is provided in the fuel passage 74. The plate width of the electrode member 81 is reduced from the upstream side to the downstream side in the fuel flow direction in the fuel passage 74. Here, the plate width of the electrode member 81 is the length along the chord of the passage forming member 71 that forms the fuel passage 74.

  As shown in FIG. 18A, the electrode member 81 has a plate width corresponding to the string at an arbitrary position of the passage forming member 71 on the upstream side of the fuel passage 74. That is, the electrode member 81 rises perpendicularly to the fuel flow direction from the inner wall of the passage forming member 71 and extends to the opposing inner wall of the passage forming member 71. Thus, the electrode member 81 has a plate width corresponding to the string of the passage forming member 71 on the upstream side of the fuel passage 74. On the other hand, as shown in FIG. 18B, the electrode member 81 has a reduced plate width on the downstream side of the fuel passage 74. That is, the electrode member 81 rises perpendicularly to the fuel flow direction from the inner wall of the passage forming member 71, but the end does not extend to the opposing inner wall of the passage forming member 71. As described above, the electrode member 81 is set such that the upstream side in the fuel passage 74 has a larger plate width and the downstream side has a smaller plate width.

  As shown in FIG. 19, the concentration sensor device 70 may be provided with a wall portion 82. The wall portion 82 separates the flow of the mixed fuel that has passed through the charging portion 75 into the sensor portion 72 side and the capturing portion 76 side. That is, the wall portion 82 is provided between the sensor portion 72 and the capturing portion 76 in the fuel passage 74 and divides the flow of the mixed fuel. Foreign matter contained in the mixed fuel charged by passing through the charging unit 75 is captured by the electrode member 81 of the capturing unit 76. As described above, the electrode member 81 has a smaller plate width toward the downstream side. Therefore, when the electrode member 81 as shown in FIG. 19 is used, the foreign matter contained in the mixed fuel is likely to move downward along the electrode member 81 in FIG. Therefore, in FIG. 19, by arranging the wall portion 82 above the downstream end portion of the electrode member 81, the mixed fuel containing more foreign matters flows below the wall portion 82. As a result, the mixed fuel containing a small amount of foreign matter flows into the upper side of the wall portion 82 where the sensor unit 72 is provided. Thereby, the inflow of the foreign material to the sensor part 72 side is reduced.

  In the fifteenth embodiment, the capturing part 76 has at least one plate-like electrode member 81. The plate-like electrode member 81 extends in parallel with the axis of the fuel passage 74, and the plate width is reduced from the upstream side to the downstream side. As a result, the mixed fuel that has passed through the charging unit 75 is effectively removed of the contained foreign matters on the upstream side where the plate width is large. Further, since the electrode member 81 extends in parallel with the fuel passage 74, the pressure loss of the mixed fuel flowing through the fuel passage 74 is reduced. Therefore, foreign matter contained in the mixed fuel can be captured upstream of the sensor unit 72 while reducing the pressure loss of the mixed fuel, and the concentration detection accuracy of the sensor unit 72 can be improved.

  In the fifteenth embodiment, the fuel passage 74 includes a wall portion 82. By separating the flow of the mixed fuel into the electrode member 81 side and the sensor unit 72 side of the capturing unit 76 by the wall portion 82, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 72 are further reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.

(16th, 17th and 18th embodiments)
The density sensor devices according to the sixteenth, seventeenth and eighteenth embodiments are shown in FIGS. 20, 22 and 24, respectively.
In the case of the sixteenth embodiment, as shown in FIG. 20, the trapping portion 76 of the concentration sensor device 70 has an electrode member 83 that extends obliquely with respect to the axis of the fuel passage 74. The electrode member 83 is formed in a plate shape, and at least one electrode member 83 is provided in the fuel passage 74. The electrode member 83 is set to have a constant plate width from the upstream side to the downstream side in the fuel flow direction in the fuel passage 74. By arranging the electrode member 83 in this way, at least a part of the width of the fuel passage 74 is narrowed from the upstream side to the downstream side.

  As shown in FIG. 21, the concentration sensor device 70 may be provided with a wall portion 84. The wall portion 84 separates the flow of the mixed fuel that has passed through the charging portion 75 into the sensor portion 72 side and the capturing portion 76 side. Foreign matter contained in the mixed fuel charged by passing through the charging unit 75 is captured by the electrode member 83 of the capturing unit 76. The electrode member 83 narrows a part of the fuel passage 74 from the upstream side to the downstream side. The wall portion 82 separates the fuel passage 74 along the narrowed electrode member 83 from the sensor portion 72 side. Therefore, the foreign matters contained in the mixed fuel easily move downward along the electrode member 83 in FIG. 21, and the mixed fuel containing a small amount of foreign matters flows into the upper side of the wall portion 84 where the sensor portion 72 is provided. To do.

  In the case of the seventeenth embodiment, as shown in FIG. 22, the capturing portion 76 of the concentration sensor device 70 has an electrode member 83 that extends with an inclination with respect to the axis of the fuel passage 74. The electrode member 83 is formed in a plate shape, and at least one electrode member 83 is provided in the fuel passage 74. The electrode member 83 is arranged in a multistage manner such that the upstream side of the fuel passage 74 is opposed more widely and the downstream side is opposed narrower. As a result, the electrode member 83 narrows the width of the fuel passage 74 from the upstream side toward the downstream side at the center of the fuel passage 74.

  As shown in FIG. 23, the concentration sensor device 70 may be provided with a wall portion 84. In the case of the seventeenth embodiment, the wall portion 84 extends in the axial direction of the fuel passage 74 on the downstream side of the most downstream electrode member 83 in which the fuel passage 74 is narrowed near the center. The sensor portion 72 is disposed on the outer peripheral side of the wall portion 84 in the radial direction of the passage forming member 71. The mixed fuel containing the charged foreign matter that has passed through the charging portion 75 reaches the wall portion 84 while flowing between the electrode members 83 of the capturing portion 76. At this time, the foreign matter that has passed through the electrode member 83 but remains in the mixed fuel passes between the pair of wall portions 84 while being guided to the center of the fuel passage 74 together with the mixed fuel by the electrode member 83. Therefore, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side.

  In the case of the eighteenth embodiment, as shown in FIG. 24, the trapping portion 76 of the concentration sensor device 70 has an electrode member 83 that extends obliquely with respect to the axis of the fuel passage 74. The electrode member 83 is formed in a plate shape, and at least one electrode member 83 is provided in the fuel passage 74. The electrode member 83 is arranged in multiple stages, with the interval facing the narrower the upstream side of the fuel passage 74 being narrower and the interval facing the lower being the wider downstream side. Thus, the electrode member 83 narrows the width of the fuel passage from the upstream side to the downstream side on the outer peripheral side of the fuel passage 74.

  As shown in FIG. 25, the concentration sensor device 70 may be provided with a wall portion 84. In the case of the eighteenth embodiment, the wall portion 84 extends in the axial direction of the fuel passage 74 on the downstream side of the most downstream electrode member 83 that narrows the fuel passage 74 on the outer peripheral side. The sensor portion 72 is disposed on the inner peripheral side of the wall portion 84 in the radial direction of the passage forming member 71, that is, between the pair of wall portions 84. The mixed fuel containing the charged foreign matter that has passed through the charging portion 75 reaches the wall portion 84 while flowing between the electrode members 83 of the capturing portion 76. At this time, the foreign matter that has passed through the electrode member 83 but remains in the mixed fuel passes through the outer peripheral side of the pair of wall portions 84 while being guided to the outer peripheral side of the fuel passage 74 together with the mixed fuel by the electrode member 83. Therefore, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side.

  In the sixteenth, seventeenth and eighteenth embodiments, the capturing portion 76 has at least one plate-like electrode member 83. The plate-like electrode member 83 extends while being inclined with respect to the axis of the fuel passage 74. The electrode member 83 narrows at least a part of the fuel passage 74 from the upstream side to the downstream side of the fuel passage 74. Therefore, the liquid flowing through the fuel passage 74 flows between the electrode members 83 that are gradually narrowed. Thereby, the foreign matter contained in the mixed fuel is easily captured by the capturing unit 76. Moreover, the wall part 84 guides the mixed fuel with few foreign substances contained among mixed fuels to the sensor part 72 side. Accordingly, the foreign matter included in the mixing can be captured upstream of the sensor unit 72, and the density detection accuracy of the sensor unit 72 can be improved.

(19th and 20th embodiments)
The concentration sensor devices according to the nineteenth and twentieth embodiments are shown in FIGS. 26 and 28, respectively.
In the case of the nineteenth embodiment, as shown in FIG. 26, the capturing unit 76 of the concentration sensor device 70 has at least one electrode member 85. The electrode member 85 is formed in a cone shape such as a cylindrical cone or a pyramid having both ends opened or a truncated cone shape, and is provided in a multistage shape. In the nineteenth embodiment, the electrode member 85 has a conical cylinder shape whose inner diameter decreases from the upstream side to the downstream side of the fuel passage 74. For example, the electrode member 85 may be formed in a net shape or a porous shape to reduce the pressure loss of the mixed fuel passing through the electrode member 85.

  As shown in FIG. 27, the concentration sensor device 70 may be provided with a wall portion 86. In the case of the nineteenth embodiment, the wall portion 86 extends in the axial direction of the fuel passage 74 on the downstream side of the most downstream electrode member 85 whose inner diameter is reduced. The sensor portion 72 is disposed on the outer peripheral side of the wall portion 86 in the radial direction of the passage forming member 71. The mixed fuel containing the charged foreign matter that has passed through the charging portion 75 reaches the wall portion 86 while being guided by the electrode member 85 of the capturing portion 76 and flowing. At this time, the foreign matter that has passed through the electrode member 85 but remains in the mixed fuel passes between the pair of wall portions 86 while being guided to the center of the fuel passage 74 together with the mixed fuel by the electrode member 85. Therefore, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side.

  In the case of the twentieth embodiment, as shown in FIG. 28, the capturing unit 76 of the concentration sensor device 70 has at least one electrode member 85. The electrode member 85 is formed in a cone shape or a truncated cone shape such as a cylindrical cone or a pyramid having both ends opened, and is provided in a multistage shape. In the case of the twentieth embodiment, the electrode member 85 has a conical cylinder shape whose inner diameter increases from the upstream side to the downstream side of the fuel passage 74. Therefore, the electrode member 85 has a shape for guiding the flow of fuel in the fuel passage 74 from the center side of the passage forming member 71 to the inner wall side of the outer periphery. For example, the electrode member 85 may be formed in a net shape or a porous shape to reduce the pressure loss of the mixed fuel passing through the electrode member 85.

Further, as shown in FIG. 29, the concentration sensor device 70 may be provided with a wall portion 86. In the case of the twentieth embodiment, the wall portion 86 extends in the axial direction of the fuel passage 74 on the downstream side of the most downstream electrode member 85 having an enlarged inner diameter. The sensor portion 72 is disposed on the inner peripheral side of the wall portion 86 in the radial direction of the passage forming member 71, that is, between the pair of wall portions 86. The mixed fuel containing the charged foreign matter passing through the charging unit 75 passes through the outer peripheral side of the pair of wall portions 86 while being guided to the outer peripheral side of the fuel passage 74 together with the mixed fuel by the electrode member 85 of the capturing unit 76. Therefore, the foreign matter contained in the mixed fuel is less likely to flow into the sensor unit 72 side.
In the nineteenth embodiment, the capturing unit 76 includes at least one electrode member 85. The electrode member 85 has an inner diameter that decreases from the upstream side toward the downstream side. Therefore, the mixed fuel passes through the electrode member 85 whose inner diameter gradually decreases. Thereby, the foreign matter contained in the mixed fuel is easily captured by the capturing unit 76.

In the twentieth embodiment, the capturing unit 76 includes at least one electrode member 85. The electrode member 85 has a shape for guiding the flow of the mixed fuel in the fuel passage 74 toward the inner wall of the passage forming member 71 from the upstream side to the downstream side. Therefore, the mixed fuel passes through the electrode member 85 that gradually approaches the inner wall of the passage forming member 71. As a result, foreign matter contained in the mixed fuel is easily captured by the capturing unit 76, and the pressure loss of the mixed fuel is relatively small.
Furthermore, in the nineteenth and twentieth embodiments, the wall portion 86 guides the mixed fuel that contains less foreign matter out of the mixed fuel that passes through the capturing portion 76 to the sensor portion 72 side. Accordingly, the foreign matter contained in the mixed fuel can be captured on the upstream side of the sensor unit 72, and the concentration detection accuracy of the sensor unit 72 can be improved.

(21st Embodiment)
A concentration sensor device according to a twenty-first embodiment is shown in FIG.
In the case of the twenty-first embodiment, as shown in FIG. 30, the concentration sensor device 70 includes a vibration generating unit 87 as vibration applying means. The vibration generator 87 is provided outside the passage forming member 71 and applies vibration to the passage forming member 71. The charging unit 75, the capturing unit 76, and the like provided in the fuel passage 74 may accumulate foreign matter due to long-term use. Therefore, the vibration generator 87 intermittently vibrates the passage forming member 71 that forms the fuel passage 74. Thereby, the charging unit 75 and the capturing unit 76 vibrate together with the passage forming member 71. In particular, by arranging the vibration generating unit 87 in the vicinity of the charging unit 75 and the capturing unit 76, vibration of the charging unit 75 and the capturing unit 76 is promoted. Accordingly, foreign matter accumulation on the charging unit 75 and the capturing unit 76 can be reduced, and the functions of the charging unit 75 and the capturing unit 76 can be maintained for a long period of time.

(Twenty-second, twenty-third, and twenty-fourth embodiments)
The density sensor devices according to the twenty-second, twenty-third, and twenty-fourth embodiments are shown in FIGS. 31, 32, and 33, respectively.
In the twenty-second embodiment, the concentration sensor device 10 includes a substrate 11 and a sensor unit 12 as shown in FIG. In the substrate 11, an insulating film 14 is formed on the end surface side opposite to the sensor unit 12 and an insulating film 17 is formed between the sensor unit 12 and the substrate 11. The sensor unit 12 has a plurality of electrodes 15 as in the first embodiment. The electrode 15 of the sensor unit 12 is protected by a protective film 16.

  In the case of the twenty-second embodiment, the concentration sensor device 10 has a second protective film 92 on the opposite side of the protective film 16 from the substrate 11. The second protective film 92 has a rough surface on the side opposite to the sensor unit 12, that is, the surface exposed to the mixed fuel. Specifically, in the case of the concentration sensor device 10 shown in FIG. 31, the second protective film 92 is formed in a rough surface shape having a convex portion 93 on the side opposite to the sensor portion 12. The second protective film 92 corresponds to the protective film portion in the claims.

  In the case of the twenty-third embodiment, as shown in FIG. 32, the concentration sensor device 10 has a second protective film 92 on the opposite side of the protective film 16 from the substrate 11. The second protective film 92 has a rough surface on the side opposite to the sensor unit 12, that is, the surface exposed to the mixed fuel. Specifically, in the case of the concentration sensor device 10 shown in FIG. 32, the second protective film 92 is formed in a rough surface shape having a sharp protrusion 94 on the side opposite to the sensor portion 12. Note that the second protective film 92 is not limited to the sharp projection 94, and may be formed into a rough surface by, for example, forming a scratch by sandblasting or the like.

  In the case of the twenty-fourth embodiment, the concentration sensor device 10 has a second protective film 92 on the opposite side of the protective film 16 from the substrate 11 as shown in FIG. The second protective film 92 has a convex surface on the side opposite to the sensor unit 12, that is, the surface exposed to the mixed fuel. Specifically, in the case of the concentration sensor device 10 shown in FIG. 33, the second protective film 92 is formed in a convex shape that protrudes in the opposite direction to the sensor portion 12 with the opposite side to the sensor portion 12 inward.

  In the twenty-second, twenty-third, and twenty-fourth embodiments, a second protective film 92 that covers the sensor unit 12 is provided. The second protective film 92 has an integral deposition limiting part at the end opposite to the sensor part 12. In the case of the twenty-second embodiment, the second protective film 92 has a deposition limiting portion on the side opposite to the sensor portion 12, and this deposition limiting portion is formed in a rough surface shape having a convex portion 93. In the case of the twenty-third embodiment, the second protective film 92 has a deposition restricting portion on the side opposite to the sensor portion 12, and this deposition restricting portion is formed in a rough surface shape having a protrusion 94. Further, in the case of the twenty-fourth embodiment, the second protective film 92 has a deposition limiting portion on the side opposite to the sensor portion 12, and this deposition limiting portion is formed in a convex shape. Therefore, in the twenty-second, twenty-third, and twenty-fourth embodiments, the adhesion of foreign matter to the surface of the second protective film 92 opposite to the sensor unit 12 is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 12 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.

(25th Embodiment)
A concentration sensor device 10 according to a twenty-fifth embodiment is shown in FIGS.
In the twenty-fifth embodiment, the concentration sensor device 10 has a flow path forming portion 95 on the opposite side of the protective film 16 from the sensor portion 12. The flow path forming part 95 is formed on the end surface of the protective film 16 opposite to the sensor part 12. The flow path forming part 95 is provided so as to form the flow of the mixed fuel toward the sensor part 12 as shown in FIG. The mixed fuel flowing through the fuel passage is guided to the side opposite to the substrate 11 of the sensor unit 12 covered with the protective film 16 by the flow path forming unit 95. Therefore, the mixed fuel actively flows on the side opposite to the substrate 11 of the sensor unit 12. As a result, even if foreign matter adheres to the protective film 16, the attached foreign matter is removed by the flow of the mixed fuel formed by the flow path forming unit 95. As shown in FIG. 36, the flow path forming part 96 may be curved toward the sensor part 12. Even in such a flow path forming part 96, the flow of the mixed fuel can be guided to the sensor part 12 side.

  In the twenty-fifth embodiment, the protective film 16 has flow path forming portions 95 and 96. The flow path forming portions 95 and 96 form a mixed fuel flow toward the sensor portion 12 on the surface of the protective film 16. Thereby, the foreign material adhering to the protective film 16 is removed by the flow of the mixed fuel. Therefore, the adhesion of foreign matter to the protective film 16 is reduced. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 12 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.

(26th Embodiment)
A concentration sensor device 10 according to a twenty-sixth embodiment is shown in FIG.
In the twenty-sixth embodiment, the concentration sensor device 10 includes a porous member 97 on the opposite side of the protective film 16 from the sensor unit 12. The porous member 97 is also a protective film part that covers the protective film 16. The porous member 97 has a plurality of holes that allow passage of the mixed fuel and restrict passage of foreign matters contained in the mixed fuel. Since the porous member 97 restricts the passage of foreign matter, the foreign matter contained in the mixed fuel does not reach the sensor unit 12 side.

  By covering the sensor unit 12 with the porous member 97 in this manner, foreign matters contained in the mixed fuel are easily attached and deposited on the end surface of the porous member 97 opposite to the sensor unit 12. Therefore, the concentration sensor device 10 may include a vibration generation unit 98 that applies vibration to the porous member 97. The vibration generating unit 98 is formed of, for example, a piezoelectric element and generates vibration when energized. The vibration generated by the vibration generating unit 98 causes the porous member 97 to vibrate. Thereby, the foreign matter adhering to or accumulating on the porous member 97 is promoted to be removed from the porous member 97 by vibration.

  Further, the vibration generating unit 98 may be a vibrating body 99 as shown in FIG. 38 instead of the piezoelectric element as described above. The vibrating body 99 is formed in a film shape and is provided on the opposite side of the porous member 97 from the sensor unit 12. When the mixed fuel flows on the opposite side of the porous member 97 to the sensor unit 12, the vibrating body 99 vibrates by the flow of the mixed fuel and gives vibration to the porous member 97. That is, the vibrating body 99 corresponds to the vibration applying means in the claims. By using the vibrating body 99, the porous member 97 can be vibrated by the flow of the mixed fuel without requiring electric power.

In the twenty-sixth embodiment, a protective film made of a porous member 97 is provided. The holes of the porous member 97 restrict the passage of foreign matters contained in the mixed fuel while allowing the flow of the mixed fuel. Therefore, the foreign matter accumulates on the porous member 97 and does not adhere to the sensor unit 12. Therefore, the adhesion and accumulation of foreign matter on the sensor unit 12 are reduced, and the detection accuracy of the specific component contained in the mixed fuel can be increased.
In the twenty-sixth embodiment, the vibration generating unit 98 that applies vibration to the porous member 97 is provided. By using the porous member 97, foreign matters contained in the mixed fuel are easily deposited on the surface of the porous member 97. Therefore, the removal of the foreign matter deposited on the porous member 97 can be promoted by vibrating the porous member 97 by the vibration generating unit 98.

(Other embodiments)
In the plurality of embodiments described above, the example in which the piezoelectric element portion 13 and the circuit portion 18 are electrically connected mainly by the through electrode 19 has been described. However, the piezoelectric element portion 13 and the circuit portion 18 are not limited to the through electrode 19 and may be electrically connected by, for example, bonding wires or bumps. As described with reference to FIG. 14, for example, some elements of the concentration sensor device 10 such as the piezoelectric element unit 13 may be electrically connected to the external mounting substrate 103 by bonding wires, solder balls 33, or the like.
Moreover, in the above-described plurality of embodiments, an example in which a mixed fuel containing a biological alcohol as a specific component is applied as a liquid has been described. However, the liquid can be arbitrarily selected without being limited to the mixed fuel, such as lubricating oil, alcohol, or water.

  The present invention described above is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

  In the drawing, 10 is a concentration sensor device, 11 is a substrate, 12 is a sensor unit, 13 is a piezoelectric element unit (deposition limiting unit), 18 is a circuit unit, 19 is a through electrode, 22 is a recess, 23 and 26 are insulating films, 27 is an insulator layer, 41 and 42 are electrode patterns (deposition limiter, piezoelectric element), 43 is an electrode part, 53 and 54 are electrode patterns (deposition limiter, piezoelectric element), and 61 and 62 are electrode patterns (deposition limiter). Part, piezoelectric element), 70 is a concentration sensor device, 71 is a passage forming member, 72 is a sensor part, 73 is a deposition restricting part, 74 is a fuel passage (liquid passage), 75 is a charging part, 76 is a capturing part, 77 is Static elimination section, 81, 83 and 85 are electrode members, 82, 84 and 86 are wall sections, 87 is a vibration generating section (vibration applying means), 92 is a second protective film (protective film section), and 95 and 96 are flow paths. Forming part 97 is a porous member (protective film part), 98 is a vibration generating part ( Dynamic application means), 99 denotes a vibrator (vibrating means).

Claims (35)

A sensor unit for detecting the concentration of a specific component contained in the liquid;
A deposition limiting unit that is integral with the sensor unit or provided upstream of the sensor unit in the liquid flow direction, and prevents accumulation of foreign matter on the sensor unit;
A concentration sensor device comprising: Comprising a substrate provided with the sensor part on one surface side;
The concentration sensor device according to claim 1, wherein the deposition limiting unit includes a piezoelectric element that oscillates when energized and promotes detachment of foreign matters attached to the sensor unit.   The concentration sensor device according to claim 2, wherein the piezoelectric element is provided on a surface opposite to the sensor unit with the substrate interposed therebetween. A circuit part provided on the same surface side as the sensor part of the substrate;
A through electrode that connects the piezoelectric element and the circuit portion through the substrate;
The concentration sensor device according to claim 3, further comprising:   The concentration sensor device according to claim 2, wherein the piezoelectric element is provided on the same side of the substrate as the sensor unit.   The concentration sensor device according to claim 2, wherein the piezoelectric element is provided between the substrate and the sensor unit.   The concentration sensor device according to claim 2, further comprising a recess provided on the substrate and recessed in the thickness direction. The sensor unit is provided on a flat surface side of the substrate that forms the recess,
8. The concentration sensor device according to claim 7, wherein the piezoelectric element is provided along an opening side of the substrate that forms the recess. An insulating film that closes the opening side of the substrate that forms the recess;
The sensor unit is provided on a flat surface side of the substrate that forms the recess,
The concentration sensor device according to claim 7, wherein the piezoelectric element is provided on a surface of the insulating film opposite to the substrate. A circuit part provided on the same surface side as the sensor part of the substrate;
A through electrode that connects the piezoelectric element and the circuit portion through the substrate;
The concentration sensor device according to claim 9, further comprising: An insulating film that closes the opening side of the substrate that forms the recess;
The concentration sensor device according to claim 7, wherein the sensor unit and the piezoelectric element are provided on a side opposite to the concave portion of the insulating film. An insulating film that closes the opening side of the substrate forming the recess;
An insulator provided on the opposite side of the insulating film from the substrate, and
The piezoelectric element is provided on the opposite side of the concave portion across the insulating film,
The concentration sensor device according to claim 7, wherein the sensor unit is provided at a position facing the piezoelectric element with the insulator interposed therebetween.   The concentration sensor device according to claim 9, wherein a gas is sealed in the recess surrounded by the substrate and the insulating film. The sensor unit has a comb-shaped electrode pattern formed of a piezoelectric element,
The concentration sensor device according to claim 2, wherein the electrode pattern is the piezoelectric element constituting the deposition limiting unit.   The concentration sensor device according to claim 14, further comprising an electrode unit that forms a potential difference with the electrode pattern on a surface opposite to the sensor unit across the substrate.   The concentration sensor device according to claim 2, wherein the deposition limiting unit has a comb-shaped electrode pattern that is stacked on a side opposite to the substrate of the sensor unit and is formed of a piezoelectric element.   3. The concentration sensor device according to claim 2, wherein the deposition limiting unit has a comb-shaped electrode pattern formed of a piezoelectric element on a surface opposite to the sensor unit across the substrate. The sensor unit has a comb-shaped first electrode pattern formed of a piezoelectric element,
The deposition limiting portion includes the first electrode pattern, and a comb-shaped second electrode pattern formed of a piezoelectric element on a surface opposite to the sensor portion across the substrate. The concentration sensor device according to claim 2.   The deposition limiting portion includes a comb-shaped first electrode pattern that is stacked on the opposite side of the sensor portion from the substrate and formed of piezoelectric elements, and a piezoelectric layer on a surface opposite to the sensor portion with the substrate interposed therebetween. The density sensor device according to claim 2, further comprising: a comb-shaped second electrode pattern formed of an element. A passage forming member that houses the sensor portion and the deposition limiting portion and forms a liquid passage through which the liquid flows;
The deposition limiting unit is
A charging unit provided on the upstream side of the sensor unit in the liquid flow direction in the liquid passage, and charging the liquid by applying a voltage to the liquid flowing in the liquid passage;
A capturing unit that is provided between the charging unit and the sensor unit of the liquid passage and captures a foreign substance charged by the charging unit;
The concentration sensor device according to claim 1, comprising:   21. The concentration sensor device according to claim 20, further comprising a wall portion that is provided in the liquid passage and separates the flow of the liquid that has passed through the charging portion into the sensor portion side and the capturing portion side.   The accumulation limiting unit is provided on the downstream side of the sensor part of the liquid passage, and applies a voltage to the liquid flowing in the liquid passage to remove a charge of the liquid charged by the charging unit. The density sensor device according to claim 20, wherein the concentration sensor device has a density sensor device.   The voltage applied to the charging unit and the voltage applied to the capturing unit are positive or negative, and maintain one polarity without reversing from one polarity to the other. The concentration sensor device according to any one of claims 20 to 22, wherein the concentration sensor device is characterized in that:   The voltage applied to the liquid in the charging unit and the capturing unit is an AC voltage of 1 kHz or more, and the maximum value of one polarity and the minimum value of the other polarity are ground voltages. 24. The concentration sensor device according to 23. The capturing part has at least one plate-like electrode member extending parallel to the axis of the liquid passage,
The electrode member has a plate width corresponding to a chord at an arbitrary position in a cross section perpendicular to the axis of the liquid passage, and the plate width decreases toward the downstream end. 25. The concentration sensor device according to any one of claims 20 to 24, wherein: The capturing part has at least one plate-like electrode member extending obliquely with respect to the axis of the liquid passage,
25. The concentration sensor device according to claim 20, wherein the electrode member has a width of at least a part of the liquid passage narrowed from the upstream side to the downstream side of the liquid passage. . The capturing part has at least one cylindrical cone-shaped electrode member,
25. The concentration sensor device according to claim 20, wherein an inner diameter of the electrode member decreases from an upstream side to a downstream side of the liquid passage. The capturing part has at least one cylindrical cone-shaped electrode member,
25. The electrode member according to claim 20, wherein the electrode member has a shape that guides the flow of the liquid in the liquid passage toward the inner wall of the passage formation member from the upstream side to the downstream side of the liquid passage. The concentration sensor device according to claim 1.   The concentration sensor device according to any one of claims 20 to 28, further comprising vibration applying means for applying vibration to the passage forming member.   The concentration sensor device according to claim 1, further comprising a protective film portion that covers the sensor portion and has the deposition limiting portion at an end opposite to the sensor portion.   31. The concentration sensor device according to claim 30, wherein the protective film portion has a rough surface opposite to the sensor portion.   31. The concentration sensor device according to claim 30, wherein the protective film portion is formed in a convex shape on the opposite side to the sensor portion.   31. The concentration sensor device according to claim 30, wherein the protective film part has a flow path forming part that forms the flow of the liquid at an end opposite to the sensor part.   31. The concentration sensor device according to claim 30, wherein the protective film portion is a porous member having a plurality of holes that allow passage of the liquid and restrict passage of the foreign matter.   35. The concentration sensor device according to claim 34, further comprising vibration applying means for applying vibration to the porous member.

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