JP2014032063A - Method of manufacturing particulate matter detection element, and particulate matter detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a particulate matter detection element having high measurement accuracy while extremely reducing insensible mass, and a particulate matter detection sensor using the particulate matter detection element.SOLUTION: The particulate matter detection sensor includes: a conductive path formed by connecting in series from one ends 103A, 103B to the other ends 104A, 104B of a pair of detection electrodes EL, ELwithout branching; detection electrode bent sections 101A, 101B each having a part bent in a substantially U shape; and breaking detection circuits 301A, 301B using substantially planar detection electrode facing parts 100A, 100B that face each other via an insulating layer 120 with a predetermined thickness, to measure a resistance value from the one ends 103A, 103B to the other ends 104A, 104B, for detecting breaking in the pair of detection electrodes EL, EL.

Description

  The present invention relates to a method for manufacturing a particulate matter detection element that is used in an exhaust system of an internal combustion engine for automobiles, etc., and detects particulate matter mainly composed of soot composed of carbon contained in a gas to be measured, and particles TECHNICAL FIELD OF THE INVENTION

In automobile diesel engines and the like, environmental pollutants contained in combustion exhaust, particularly particulate matter (hereinafter referred to as PM) mainly composed of soot particles and soluble organic components (SOF) are collected. For this purpose, a diesel particulate filter (hereinafter referred to as DPF) is installed in the exhaust passage. The DPF is made of porous ceramics having excellent heat resistance, and traps PM by allowing combustion exhaust gas to pass through partition walls having a large number of pores.
If the amount of collected PM exceeds the allowable amount, the DPF will become clogged and the pressure loss will increase, or the DPF will be damaged by the heat generated when burning excessively accumulated PM, causing the PM to pass through. The collection ability is restored by periodically performing a regeneration process.

Various PM detection sensors for detecting PM in the gas to be measured have been proposed in order to appropriately detect the DPF regeneration timing and to detect abnormalities such as PM slipping at an early stage.
For example, in Patent Document 1, PM in a measurement gas is deposited between a pair of comb electrodes facing a surface of an insulator with a predetermined gap therebetween, and a resistance value that changes according to the amount of deposition, There is disclosed a PM detecting element that measures electrical characteristics such as capacitance and impedance and detects the amount of PM contained in a gas to be measured.
Patent Document 2 discloses a plate-shaped element base, a pair of measurement electrodes disposed on the element base, characteristic measurement means for measuring electrical characteristics between the pair of measurement electrodes, and the above A pair of the measurement electrodes and a particulate matter amount calculation means for obtaining the amount of particulate matter collected around the measurement electrodes based on a change amount of the electrical characteristics measured by the property measurement means; Each measurement electrode constituting the measurement electrode has a comb-tooth shape having a plurality of comb-tooth portions arranged in a plane and a comb-bone portion connecting the plurality of comb-tooth portions of each measurement electrode at one end thereof. The comb teeth of each of the measurement electrodes are arranged so as to be engaged with each other with a gap, and the comb bone of at least one of the measurement electrodes is a dielectric. Particulate matter covered by a comb bone covering portion comprising Out apparatus is disclosed. This particulate matter detection apparatus detects particulate matter by attaching a particulate matter to a pair of measurement electrodes and the periphery thereof and measuring a change in electrical characteristics between the pair of measurement electrodes.

  In such a conventional PM detection element, thick film printing, chemical vapor deposition (CVD), thin film printing such as physical vapor deposition (PVD), etc. are performed on the surface of an insulating substrate such as alumina or a conductive substrate such as zirconia. A technique is used in which a plurality of electrodes formed in a substantially strip shape are arranged at regular intervals and are opposed to each other so that the polarities are alternately changed, and a so-called comb-like pattern is used. In the PM detection element with the comb-like electrodes facing each other, there is a dead mass that cannot detect the electrical characteristics between the electrodes until the amount of PM deposited between the pair of electrodes exceeds a certain amount, and an abnormality of the DPF It is desired to reduce this dead mass as much as possible in order to detect the above in an early and reliable manner.

Further, when a certain amount or more of PM is accumulated between the detection electrodes and becomes saturated, the electrical characteristics detected between the detection electrodes become constant, and the PM in the gas to be measured cannot be detected.
Therefore, in the PM detection device, in order to continue the PM detection, when the amount of PM adhering between the detection electrodes reaches a limit, the attached PM is burned and removed by heating with a heater or the like to detect the PM. Is trying to play.

  Furthermore, in Patent Document 3, in such a gas sensor, a disconnection detection resistor having a predetermined resistance value is paired as a disconnection detection unit that detects the presence or absence of a disconnection of a conduction path that connects between the detection unit and the resistance measurement unit. Disclosed is a gas sensor characterized in that it is provided on the side of the resistance measuring means so as to conduct the detection electrode and to be in parallel with the detection resistance formed between the detection electrodes. It is possible.

However, in the conventional PM detection element, when forming a comb-like electrode, when using a general thick film printing, the gap between the detection electrodes is about several tens of μm, and the rheological characteristics of the printing paste and About 20 μm was the limit due to restrictions on the production of the mask formed on the printing screen.
In addition, when thin film printing such as CVD or PVD is used, it is possible to form a very precise pattern, but on the other hand, the equipment cost is high and the manufacturing cost may be increased.
In addition, since the detection electrode to be formed is necessarily a thin film, it is provided in the combustion exhaust passage of an internal combustion engine such as an automobile engine, and the vibration from the outside, the temperature change of the gas to be measured, and the PM detection element are heated. In PM detection elements that are directly exposed to extremely harsh usage environments such as thermal stress when burning and removing PM deposited on the detection unit, and thermal stress due to adhesion of moisture contained in the gas to be measured, There is a risk that transpiration, peeling, and the like may occur, and sufficient durability may not be obtained.

  Furthermore, in a particulate matter detection element that detects electrical characteristics that change according to the amount of particulate matter deposited between a pair of electrodes, the change in resistance value between the detection electrodes is measured as electrical characteristics. However, even in the case of measuring capacitance, the state where a disconnection due to some defect occurs in each detection electrode and the state where no particulate matter is deposited between the detection electrodes are electrically equivalent. Therefore, there is a possibility that it is not possible to distinguish between a defect such as a disconnection in the detection electrode and a state where PM is not deposited between the detection electrodes.

  Accordingly, in view of such circumstances, the present invention measures the electrical characteristics that change according to the amount of particulate matter contained in the measurement gas deposited on the detection unit, and thereby determines the amount of particulate matter in the measurement gas. Provides a method for manufacturing a particulate matter detection element having a structure with extremely low dead mass and high measurement accuracy, and detecting particulate matter using the particulate matter detection element An object of the present invention is to provide a highly reliable particulate matter detection sensor that can detect the presence or absence of a defect such as a disconnection in an element.

In the present invention (1, 1a, 1b, 1c, 1d), the light is collected by a detection unit (10, 10c, 10d) having a pair of detection electrodes (EL _A , EL _B ) facing each other at least at a predetermined distance. A particulate matter detection element (2, 2, 2) which detects the amount of particulate matter contained in the gas to be measured by detecting electrical characteristics between the detection electrodes, which change according to the amount of particulate matter deposited. 2b, 2c, 2d), each of the detection electrodes constituting the pair of detection electrodes (EL _A , EL _B ) has one end (103A, 103B, 103Ac, 103Bc, 103Ad, 103Bd) to the other end (104A, 104B, 104Ac, 104Bc, 104Ad, 104Bd), a conduction path connected in series is formed, and a folded portion (1 bent) is formed. 1A, 101B, 101Ad, 101Bd) and a detection electrode facing portion (100A, 100B) facing each other via an insulating layer (120) forming a predetermined distance between the detection electrodes, and the one end portion ( 103A, 103B, 103Ac, 103Bc, 103Ad, 103Bd) to the other end (104A, 104B, 104Ac, 104Bc, 104Ad, 104Bd), and the pair of detection electrodes (EL _A , EL _B ) includes a disconnection detection circuit unit (301A, 301Aa, 301Ab, 301B, 301Ba, 301Bb) for detecting the presence or absence of disconnection.

Further, the present invention provides a resistance value between the one end (103A-103B, 103Ac-103Bc, 103Ad-103Bd) or between the other end (104A-104B, 104Ac-104Bc, 104Ad-104Bd). And a PM detection circuit section (31) for detecting the amount of particulate matter deposited between the detection electrodes by detecting any one of capacitance and impedance.
Further, according to the present invention, the particulate matter detection element (2, 2b, 2c, 2d) includes the detection unit (10, 10c, 10d) and a substrate unit (20, 20b, 20c, 20d) on which the detection unit is mounted. The detection part (10, 10c, 10d) is formed in a substantially flat plate shape with a film thickness of 100 μm or more and 500 μm or less, and the detection electrode facing part (100A, 100B) and a film of 5 μm or more and 20 μm or less It is a laminated structure in which the insulating layer (120) formed in a substantially flat shape with a thickness is repeatedly laminated.

According to the present invention, the particulate matter that detects the amount of particulate matter in the measurement gas by measuring the electrical characteristics that change according to the amount of particulate matter contained in the measurement gas deposited on the detection unit. In the substance detection element, the disconnection detection circuit unit (301A, 301B) determines whether or not there is a defect inside the detection electrode (EL _A , EL _B ) from the one end (103A, 103B) to the other end (104A). , 104B), and the PM detection circuit unit has an electrical characteristic that changes in accordance with the amount of particulate matter deposited between the detection electrodes (EL _A , EL _B ) after being detected by measuring DC resistance up to 104B). In order to detect by (31), whether the electrical characteristics detected as in the past are due to defects inside the detection electrodes such as disconnection or whether particulate matter is not deposited between the detection electrodes. Distinction No portions that become come, it is possible to maintain high reliability.
In addition, by forming the detection unit (10) with a laminated structure, the insulating layer (120) can be formed to be extremely thin with a thickness of 20 μm or less, the distance between the detection electrodes is short, and the dead mass is small. Therefore, it is possible to provide a method for manufacturing a particulate matter detection element having a structure with a very small measurement system and a high measurement system.
In conventional methods such as thick film printing, it is extremely difficult to form the gap between the detection electrodes to 20 μm or less, but by taking a laminated structure as in the present invention, the insulating layer (120) can be easily formed to 5 μm to 20 μm. It becomes possible to form in the following ranges, and extremely insensitive mass can be reduced.

The schematic diagram which shows the basic composition of the particulate matter detection sensor of this invention. The block diagram which shows the whole outline | summary of the particulate matter detection sensor in the 1st Embodiment of this invention. The perspective view which shows the outline | summary of the detection electrode laminated body which is the principal part of the particulate matter detection element in the 1st Embodiment of this invention. FIG. 2B is a cross-sectional view of the detection electrode laminate along AA in FIG. 2A. FIG. 2 is a developed perspective view showing an outline of a particulate matter detection element according to the first embodiment of the present invention. The equivalent circuit diagram which shows the operation state of this invention in the time of normal. The equivalent circuit diagram which shows an example of the operation state of this invention at the time of a disconnection. The equivalent circuit diagram which shows the operation state at the time of the normal of a comparative example. The equivalent circuit diagram which shows the problem of a comparative example and shows an example of the operation state at the time of a disconnection. Sectional drawing for demonstrating the embedding process in the manufacturing method of the detection electrode laminated body which is the principal part of the particulate matter detection element in 1st Embodiment. FIG. 6B is a developed perspective view illustrating the detailed structure of the detection electrode laminate and explaining the outline of the lamination step subsequent to FIG. 6A. The perspective view which shows the outline | summary of the detection electrode laminated body cutting-out process following FIG. 6B. The block diagram which shows the outline | summary of the particulate matter detection sensor in the 2nd Embodiment of this invention. The block diagram which shows the outline | summary of the particulate matter detection sensor in the 3rd Embodiment of this invention. The perspective view which shows the outline | summary of the particulate matter detection element in the 4th Embodiment of this invention. FIG. 9B is a developed perspective view showing a detailed structure of the detection electrode laminate of FIG. 9A. The block diagram which shows the whole outline | summary of the particulate matter detection sensor in the 5th Embodiment of this invention. FIG. 10B is a developed perspective view showing an example of a detailed structure of the detection electrode laminate of FIG. 10A.

With reference to FIG. 1A, the basic structure of the particulate matter detection sensor 1 of the present invention will be described. FIG. 1A is a conceptual diagram expressing the basic configuration of the particulate matter detection sensor 1 of the present invention in a most simplified manner.
The particulate matter detection sensor 1 has the above-described detection that changes according to the amount of particulate matter collected and deposited on the detection unit 10 including a pair of detection electrodes EL _A and EL _B facing each other at least at a predetermined distance. It is constituted by a particulate matter detection element 2 that detects electrical characteristics between the electrodes and detects the amount of particulate matter contained in the gas to be measured, and a circuit unit 3.
The particulate matter detection element 2 includes a detection unit 10 and a substrate unit 20 on which the detection unit 10 is mounted.

The detection unit 10 is formed of a laminated structure having at least a pair of detection electrodes EL _A and EL _B opposed to each other with an insulating layer 120 interposed therebetween.
The pair of detection electrodes EL _A and EL _B are displayed with different hatching for convenience in order to distinguish which electrode is used, but both electrodes are formed of the same material.
Specific materials will be described later together with the manufacturing method.
The circuit unit 3 detects a detection electrode disconnection detection circuit unit 30 that detects the presence / absence of a disconnection in the detection electrodes EL _A and EL _B , and detects electrical characteristics that change according to the amount of particulate matter deposited between the detection electrodes. The PM detection circuit unit 31 is configured.

The detection electrode disconnection detection circuit unit 30 includes a first detection electrode disconnection detection circuit unit 301A and a second detection electrode disconnection detection circuit unit 301B that detect the presence / absence of disconnection in each of the pair of detection electrodes EL _A and EL _B. It is configured.
The first and second detection electrode disconnection detection circuit portions 301A and 302B are, for example, PM detection terminals provided at the other end from the disconnection detection terminal portions 103A and 103B provided at one end of the detection electrodes EL _A and EL _B. The resistance values up to 104A and 104B are detected to detect the presence or absence of disconnection inside the detection electrodes EL _A and EL _B.
As a specific disconnection detection method, by measuring a potential difference between both ends by passing a weak current, the internal resistances R _ELA and R _ELB of the detection electrodes EL _A and EL _B can be measured. The presence or absence of disconnection can be determined by comparing with the threshold value.

In the present invention, the detection electrodes EL _A and EL _B are provided with detection electrode folded portions 101A and 101B in which a part of the detection electrode facing portions 100A and 100B formed in a substantially flat plate shape is folded back into a substantially U-shape. Connected to the parts 102A and 102B and connected to the disconnection detection terminals 103A and 103B and the PM detection terminals 104A and 104B via the detection lead parts 102A and 102B, from the disconnection detection terminals 103A and 103B. The PM detection terminals 104A and 104B are characterized by a one-stroke writing that forms a single conductive path connected in series without branching.
By making the detection electrodes EL _A and EL _B into a shape having such a continuous conductive path without branching, it is possible to reliably detect the presence or absence of disconnection.

The PM detection circuit unit 31 has one of the electrical characteristics of DC resistance, capacitance, and AC impedance that change according to the amount of particulate matter deposited between the pair of detection electrodes EL _A and EL _B. It is detected by measuring one of the resistance value, capacitance, and impedance between the end portions 103A-103B or the other end portion 104A-104B, and the amount of particulate matter contained in the gas to be measured is calculated. be able to.
The substrate unit 20 is provided with a heating element 220 that generates heat when energized to stabilize the temperature at the time of detection, or to burn off and remove particulate matter deposited on the surface of the detection unit 10 for sensor regeneration. You may make it use.
Energization of the heating element 220 can be controlled by a heat generation control circuit unit 32 described later.

With reference to FIG. 1B, FIG. 2A, FIG. 2B, and FIG. 3, the more specific structure of the particulate matter detection sensor 1 in this embodiment is demonstrated.
As shown in FIG. 1B, the particulate matter detection sensor 1 in this embodiment is covered with a housing 4 (not shown) and is subjected to measurement such as combustion exhaust discharged from an internal combustion engine, as with a known particulate matter detection sensor. It is used in a state of being fixed to the measurement gas flow path 5 through which gas flows.
The particulate matter detection element 2 is fixed in a substantially cylindrical housing 4 via a known fixing member such as an insulator so that the detection unit 10 fixed to the tip of the substrate unit 20 is exposed to the gas to be measured. It has become.

In the present embodiment, as shown in FIG. 2A, in the detection unit 10, electrode folding portions 101A and 101B are provided at a plurality of locations so that a pair of detection electrodes EL _A and EL _B are opposed to each other at a plurality of locations. It is formed in a substantially comb-tooth shape.
However, also in the present embodiment, as described above, one serial conductive path is configured without branching from the disconnection detection terminals 103A and 103B to the PM detection terminals 104A and 104B.

Further, in this embodiment, as shown in FIG. 2A, the disconnection detection terminals 103A and 103B and the PM detection terminals 104A and 104B are arranged so that the return leads 105A and 105B are arranged at one end of the detection unit 10. Is formed.
Furthermore, the detection unit 10 in the present embodiment does not print and form an electrode pattern on the surface of a conventional insulating substrate, but as shown in FIG. 2B, the detection electrode facing units 100A and 100B formed in a flat plate shape It is formed by a laminated structure in which insulating layers 120 for forming a predetermined distance between detection electrodes are stacked.

On the other hand, in this embodiment, as shown in FIG. 2B, the film thickness in the stacking direction of the detection electrode facing portions 100A and 100B is formed to be 100 μm or more and 500 μm or less, and the film thickness in the stacking direction of the insulating layer 120 is 5 μm. It is formed to 20 μm or less.
The distance between the pair of detection electrodes ELA and ELB exposed on the surface of the detection unit 10 is 5 μm or more and 20 μm or less by forming the insulating layer 120 to be extremely thin and stacking the detection electrode facing portions 100A and 100B. It becomes possible to set to an extremely short distance, and it is possible to eliminate the dead mass.
A specific manufacturing method in which the detection unit 10 has such a laminated structure will be described later.

As shown in FIG. 3, the substrate portion 20 in the present embodiment includes a heating element 220 that generates heat when energized between substantially flat insulating substrates 200 and 210, and is formed on the surface of the insulating substrate 200. The PM detection terminal connection portions 106A and 106B, the disconnection detection terminal connection portions 107A and 107B, the lead portions 108A and 108B, 109A and 109B, and the PM detection external connection terminals 110A and 110B by a known method such as thick film printing and plating. A predetermined conductor pattern including the disconnection detection external connection terminals 111A and 111B is formed.
The disconnection detection terminals 103A and 103B of the detection unit 10 are connected to the disconnection detection terminal connection units 107A and 107B and the PM detection terminals 104A and 104B, respectively, and mounted on the surface of the substrate unit 20 with the PM detection terminal connection units 106A and 106B.・ It is fixed.
On the surface of the insulating substrate 210 formed in a substantially flat plate shape, a heating element 220 and a pair of heating element lead portions 221A and 221B are formed by a known method such as thick film printing and plating, and generate heat when energized. The heating element 220 and the heating element lead portions 221A and 221B are covered with the insulating substrate 200, and the heating element terminal portions 223A and 223B provided on the back side of the insulating substrate 210 through the through-hole electrodes 222A and 222B. It is connected to the.

The effect of the particulate matter detection sensor 1 in the first embodiment of the present invention will be described with reference to FIGS. 4A and 4B, and the conventional insulation shown as a comparative example with reference to FIGS. 5A and 5B A problem of the particulate matter detection sensor 1z in which a pair of comb-like electrodes are formed thick on the surface of the substrate will be described.
When the particulate matter detection sensor 1 of the present invention is used, resistance values detected by the disconnection detection circuit units 301A and 301B at both ends of the detection electrodes EL _A and EL _B (between 103A and 104A and between 103B and 104B). the detection electrode _EL a, the internal resistance _R ELA of EL _B, in addition to _{R ELB,} the detection electrodes _EL a, affected by particulate matter deposited on the surface of the EL _B.
At this time, since the resistance path formed by the deposition of the particulate matter is formed so as to bridge the opposing detection electrode facing portions 100A and 100B of the detection electrodes EL _A and EL _B , the resistance path is shown in FIG. 4A. As described above, the internal resistance r _PM formed by the deposition of the particulate matter is connected in parallel to the internal resistances R _ELA and R _{ELB of the output} electrodes EL _A and EL _B , and the respective detection electrodes EL. _The detection resistance values R _A and R _B detected at both ends of _A and EL _B are the relationship of 1 / R _A = 1 / R _ELA + 1 / r _PM , 1 / R _B = 1 / R _ELB + 1 / r _PM Holds.

For example, when the internal resistances R _ELA and R _ELB of the detection electrodes EL _A and EL _B are about 1Ω to 200Ω, the resistance value r _PM of the resistance path formed by the deposition of the particulate matter is the deposition of the particulate matter. Depending on the amount, even if it changes to about 1000Ω to 10 ⁶ Ω, both-end resistance values R _A and R _B detected at both ends of the detection electrodes EL _A and EL _B are about 0.999Ω to 199.96Ω, When a disconnection occurs in any of the conduction paths of the detection electrodes EL _A and EL _B , the resistance is 1000Ω or more.
For this reason, as shown in FIG. 4B, since the internal resistances R _ELA and R _ELB of the detection electrodes EL _A and EL _B in which the disconnection has occurred increase to 10 ⁵ Ω or more, in the disconnection detection circuit units 301A and 301B, By providing the disconnection determination means 302A and 302B for comparing the detection resistors R _A and R _B with a predetermined resistance threshold R _REF (for example, 1000Ω), it is possible to detect the presence or absence of the disconnection very easily.

In addition, when the PM-derived resistance R _PM between the PM detection terminals 104A and 104B is measured as an electrical characteristic that changes according to the amount of particulate matter deposited between the opposing detection electrodes EL _A and EL _B , It is possible to detect only a change in resistance value due to the amount of the deposited substance.
In addition, when a disconnection is detected, the particulate matter calculation can be stopped by issuing an abnormality warning.

On the other hand, when a conventional particulate matter detection sensor 1z in which a pair of detection electrodes facing each other with a predetermined gap are formed on a surface of an insulating substrate in a comb-like shape by thick film printing is used in a normal state, FIG. as shown in 5A, the detection resistor _{R SUM} is detected between the detection electrodes, the detection electrodes _EL AZ, each internal resistance _r a of _{EL BZ,} and _{r B,} varies depending on the deposition amount _{Q PM} of the particulate matter The PM-derived resistance R _PM is equivalent to that connected in series, and the PM deposition amount Q _PM can be calculated by measuring the combined resistance R _PM + r _A + r _B.

However, in the conventional particulate matter detection sensor 1z, when a disconnection abnormality occurs in any of the detection electrodes EL _AZ and EL _BZ , the disconnection point and the PM-derived resistance R _PM are connected in series as shown in FIG. 5B. In this state, the PM-derived resistance changes in a large range from 1000Ω to 10 ⁶ Ω, and the detection resistance when the disconnection occurs is about 10 ⁵ Ω. There is a possibility that it is not possible to distinguish and detect whether particulate matter is not deposited between EL _AZ and EL _BZ .
Furthermore, even when a disconnection occurs, when particulate matter is deposited so as to bridge the disconnection portion, a resistance path r _PMZ connected in parallel so as to bypass the disconnection portion is formed. There is also a possibility that the disconnection is not detected.
The present invention has been made to solve such a problem that may occur in the conventional particulate matter detection sensor 1z.

Here, with reference to FIG. 6A, FIG. 6B, and FIG. 6c, the manufacturing method of the detection part 10 which is the principal part of the particulate matter detection sensor 1 of this invention is demonstrated.
The insulating layer 120 is made of an insulating oxide material selected from partially stabilized zirconia represented by 8YSZ (ZrO ₂ ) _0.92 (Y ₂ O ₃ ) _0.08 ), MgO, or Al ₂ O _3. By adding a predetermined binder, plasticizer, dispersant, solvent, etc., and using a known film formation method such as thick film printing or doctor blade method, the film has a substantially flat shape with a film thickness of 5 μm or more and 20 μm or less. The insulating thin film sheet (120) formed and the insulating thick film sheet (120) formed in a substantially flat plate shape with a film thickness of 100 μm or more and 500 μm or less are formed.

In the conductive sheet forming step, a conductive sheet for forming the detection electrodes EL _A and EL _B is formed.
The conductive sheet is LNF (LaNi _0.6 Fe _0.4 O ₃ ), LSN (La _1.2 Sr _0.8 NiO ₄ ), LSM (La _1-X Sr _X MnO _3-δ ), LSC (La _{1-X Sr X CoO 3-} δ), LCC (La 1-X Ca X CrO 3-δ), LSCN (La 0.85 Sr 0.15 Cr 1-X Ni X O 3-δ) (0.1 ≦ X ≦ 0.7) Add a predetermined binder, plasticizer, dispersant, solvent, etc. to the perovskite type conductive oxide material selected from any one of the known methods such as doctor blade method, press method, etc. Depending on the forming method, a conductive sheet (100) formed in a substantially flat shape with a film thickness of 100 μm or more and 500 μm or less is used.
A conductive sheet formed of LNF, LSN, LSM, LSC, LCC, LSCN, or the like becomes a conductive oxide having a conductivity of 10 ⁻² S / cm or more by firing.

In the insulating sheet forming step, insulating oxidation selected from partially stabilized zirconia represented by YSZ ((ZrO ₂ ) _0.92 (Y ₂ O ₃ ) _0.08 ), MgO, or Al ₂ O ₃ The material is formed using a known molding method such as a doctor blade method or a thick film printing method.
The insulating sheet formed in the insulating sheet forming step becomes an insulating oxide having an electric conductivity of 10 ⁻⁵ S / cm or less, which constitutes the insulating layer 120, by firing.

In the insulating sheet conductive sheet embedding step shown in FIG. 6A in the order of (a) to (d), the insulating thick film sheet (120) and the conductive sheet (100) having the same film thickness prepared in advance are used. By overlapping and punching simultaneously using the molds M1 and M2, the insulating film thickness sheet can be embedded in the conductive sheet without any gap.
By appropriately changing the pattern of the mold, it is possible to embed an insulating sheet partitioned into a predetermined shape at a plurality of predetermined positions of the conductive sheet.
In the conductive sheet insulating sheet embedding step of embedding the conductive sheet 100 partially partitioned into a predetermined shape with the same film thickness at a predetermined position of the insulating thin film sheet 120 having a film thickness of 5 μm or more and 20 μm or less, When such a method is difficult, thick film printing may be performed by overlapping a conductive sheet having a predetermined pattern and an insulating sheet.

The detection unit 10 is formed by laminating a sheet in which the insulating sheet 120 and the conductive sheet 100 are combined in a predetermined pattern through a laminating process as illustrated in FIG. 6B.
For example, in the sheet indicated as layer A in FIG. 6B, the insulating thick film sheet 120 is embedded at five locations in the conductive thick film sheet 100, thereby detecting the detection electrode return lead portion 105A, the detection electrode facing portion 100A, The detection electrode lead part 102 </ b> B and the detection electrode return lead part 105 </ b> B can be arranged via the insulating layer 120.
In addition, in order to clarify which part of the pair of detection electrodes EL _A and EL _B constitutes, for convenience, the EL _A side and the EL _B side are shown separately hatched. The insulating sheet 120 is embedded in one conductive sheet 100.
The B layer is obtained by rotating the A layer by 180 degrees in the plane direction.

The MA layer connects the A layer and the A layer in series, and the detection electrode returns to a predetermined position in the insulating layer 120 by embedding the conductive sheet 100 in predetermined four locations of the insulating thin film sheet 120. The lead portion 105A, the detection electrode return portion 101A, the detection electrode lead portion 102B, and the detection electrode return lead portion 105B are arranged.
The MB layer connects the B layer and the B layer in series, and is obtained by rotating the MA layer 180 degrees in the plane direction.

The C layer serves to insulate the detection electrode lead portions 102A and 102B and the detection electrode return lead portions 105A and 105B while insulating the detection electrode facing portions 100A and 100B facing each other. By embedding the conductive sheet 100 in four predetermined locations, the detection electrode return lead portion 105A, the detection electrode lead portion 102A, the detection electrode lead portion 102B, and the detection electrode return lead portion 105B are arranged at predetermined positions in the insulating layer 120. It has been installed.
A layer, MA layer, A layer, C layer, B layer, MB layer, B layer, C layer, A layer ... By repeatedly laminating, the detection electrodes EL _A and EL _B are at least substantially flat. The detection electrode facing portions 100A and 100B formed in the first, the detection electrode folded portions 101A and 101B partially bent in a substantially U shape, and the detection electrode lead portions 102A and 102B are detected. Terminal portions 103A and 103B are formed, PM detection terminal portions 104A and 104B are formed at the other end, and one wire connection detection terminal portions 103A and 103B to PM detection terminal portions 104A and 104B are connected in series. A conduction path can be formed.

The AE layer performs one end processing of the detection unit 10, and the insulating sheets 120 are embedded in three portions of the conductive thick film sheet 100, and the detection electrode facing unit 100 AE is the detection electrode folding unit 101 A. And the detection electrode return lead portion 105A, and the detection electrode facing portion 100BE is connected to the detection electrode lead portion 102B and the detection electrode return lead portion 105B.
In addition, the ETP layer is composed only of the insulating sheet 120 and is intended to insulate and maintain one end face of the detection unit 10.

By repeatedly laminating the C layer, the detection electrode lead portions 102A and 102B and the detection electrode return lead portions 105A and 105B can be formed to have arbitrary lengths.
The END layer performs processing of the other end of the detection unit 10, and the conductive thick film sheet 100 is embedded in predetermined four places of the insulating thick film sheet 120 (conversely, the predetermined thickness of the conductive thick film sheet 100 is set. Insulating film thickness sheet 120 may be embedded in the three locations) to form disconnection detection terminals 103A and 103B and PM detection terminals 104A and 104B, which are arranged on one side of detection unit 10.

Further, in the actual manufacturing process, as is commonly used in the manufacturing method of multilayer ceramics, the detection electrode layer is formed with high accuracy by providing a frame portion that covers the periphery of each layer, forming a positioning hole, and laminating. EL _A and EL _B can be opposed to each other with a certain gap while forming a conduction path connected in series without branching from one end to the other end.

In addition, in this embodiment, after forming the width | variety of each layer thickly and laminating | stacking, the several detection part 10 can be efficiently formed by cutting out to predetermined width | variety like Kintaro-an.
As shown in FIG. 6C, the detection unit aggregate 10MLT obtained in this way is cut into a predetermined thickness by using a cutting means such as a dicing saw to complete the detection unit 10.
If this is mounted on the substrate part 20 as shown in FIG. 3, the particulate matter detection element 2 which is the main part of the present invention is completed.

It should be noted that the individual pieces may be cut out from the detection unit assembly 10MLT before firing or after firing.
If it is processing before firing, there is a merit that the processing is easy because it is in the form of a molded body, but there is a demerit that dimensional variation of the detection unit 10 increases because there is a dimensional change due to firing.
If the processing is performed after firing, the strength of the detection unit 10 is high, so that there is a demerit that the processing becomes difficult. However, since there is no dimensional change due to firing, there is an advantage of high dimensional accuracy after processing.
Accordingly, it is possible to appropriately select at which time the processing should be performed depending on whether the production cost is important or the processing accuracy is important.

In addition, since the detection unit 10 which is a main part of the present invention has a laminated structure as described above, in the same way as a laminated structure such as a multilayer substrate or a piezoelectric actuator, impurities may be mixed during the processing step. There is a risk of delamination due to the difference in thermal expansion coefficient between the layers.
If delamination occurs in the detection electrodes EL _A and EL _B , conduction between the respective layers may be hindered and a local disconnection may occur. The presence or absence of disconnection can be detected.
Therefore, even when the detection unit 10 has a laminated structure, the insulative distance between the detection electrodes is extremely shortened to eliminate the dead mass, so that high reliability can be maintained.

With reference to FIG. 7, a particulate matter detection sensor 1a according to a second embodiment of the present invention will be described. Since the same reference numerals are given to the same components as those in the above embodiment, detailed description thereof is omitted, and the same components but different parts are given the same reference characters with alphabets as branch numbers. The explanation will be focused on. The same applies to the following embodiments.
In the above embodiment, the heating element energization control circuit unit 32 that controls the energization of the heating element 220 provided in the substrate unit 20 is provided independently of the disconnection detection circuit unit 30 and the PM detection circuit unit 31. However, the present embodiment is different in that the disconnection detection circuit unit 30 (301Aa, 301Ba) is configured to be used for the detection and temperature control of the heating temperature of the heating element 220.

Since the internal resistances R _A and R _B from the disconnection detection terminals 103A and 103B of the detection electrodes EL _A and EL _B to the PM detection terminals 104A and 104B have a correlation with temperature, the detected internal resistance R The heat generation temperatures T ₁ and T ₂ of the heat generator 220 can be calculated from _A and R _B.
The obtained temperature result is fed back to the heater control circuit 320, and the heater control circuit 320 controls the driving of the driver 321 that opens and closes the switching element 322 that controls energization to the heating element 220 according to the temperature result. To do.
According to the present embodiment, in the same manner as the above-described embodiment, it is possible to detect the presence or absence of disconnection inside the detection unit 10 and to detect particulate matter with high accuracy. It becomes possible to control more accurately.

With reference to FIG. 8, a particulate matter detection sensor 1b according to a third embodiment of the present invention will be described.
In the above-described embodiment, in order to burn off particulate matter deposited on the detection unit 10 or improve detection accuracy by keeping the temperature at the time of detection constant, the heat generated by energization inside the substrate unit 20 is generated. Although the example in which the body 220 is provided is shown, in the present embodiment, the heating element 220 is not provided, and each of the pair of detection electrodes EL _A and EL _B is used as a resistance heating element. Is different.
In the present embodiment, each of the disconnection detection circuit units 301Ab and 301Bb for detecting a disconnection between both ends 103A-104A and 103B-104A of the pair of detection electrodes EL _A and EL _B has a heat generation control function. Features.
Specifically, not only the presence or absence of disconnection is detected by measuring the internal resistance between both ends 103A-104A and 103B-104A of the detection electrodes EL _A and EL _B , but the resistance value of the conductor has a temperature dependency. Therefore, the temperatures of the detection electrodes EL _A and EL _B are calculated from the measured resistance values R _A and R _B.

Furthermore, since the amount of heat generated by the resistor is proportional to the supplied power, the amount of power supplied to the detection electrodes EL _A and EL _B from the variable power sources 32Ab and 32Bb is increased or decreased while monitoring the resistance values R _A and R _B. Thus, the detection electrodes EL _A and EL _B can be maintained at a desired temperature.
According to the present embodiment, in addition to the same effects as the above embodiment, when the particulate matter deposited on the detection electrodes EL _A and EL _B is saturated, the power supplied from the variable power sources 32Ab and 32Bb is reduced. It is also possible to raise the temperature of the detection electrodes EL _A and EL _B and burn and remove the deposited particulate matter.

With reference to FIG. 9A and FIG. 9B, the particulate matter detection sensor 1c and the detection electrode laminated body 10c which is the principal part in the 4th Embodiment of this invention are demonstrated.
In the above-described embodiment, the disconnection detection terminal portions 103A and 103B and the particulate matter detection terminal portion that are provided with the detection electrode return leads 105A and 105B so as to penetrate the inside of the detection electrode laminate 10 and are connected to the outside. The configuration in which 104A and 104B are pulled out to one end edge of the detection electrode laminate 10 has been described. However, as shown in FIGS. 9A and 9B, the disconnection detection terminal is not provided without providing the detection electrode return leads 105A and 105B. The parts 103Ac and 103Bc and the particulate matter detection terminal parts 104Ac and 104Bc are divided and exposed in four places, and the conductors 106Ac, 106Bc, 107Ac, 107Bc, 108Ac, 108Bc, 109Ac, 109Bc, 110Ac, provided on the surface of the substrate part 20c, 110Bc, 111Ac, and 111Bc wiring patterns Connection terminals 110Ac to achieve the connection, 110Bc, 111Ac, the point where the 111Bc to be disposed on the proximal side of the particulate matter detection device 2c differs.

Since the detection electrode return lead portions 105A and 105B are not formed, as shown in FIG. 9B, the configuration of each layer is simple and the manufacture is easier than the above embodiment.
Also in this embodiment, as in the above-described embodiment, the pair of detection electrodes EL _A and EL _B does not branch from the disconnection detection terminals 103Ac and 103Bc to the PM detection terminals 104Ac and 104Bc. Since the path is formed, the presence or absence of disconnection inside the detection electrodes EL _A and EL _B can be detected very easily.

With reference to FIG. 10A and FIG. 10B, the particulate matter detection sensor 1d and the detection electrode laminate 10d in the fifth exemplary embodiment of the present invention will be described.
In the above-described embodiment, the detection electrode folded portions 101A, 101B, and the like by laminating the insulating sheet 120 embedded in the conductive sheet 100 or by laminating the conductive sheet 100 embedded in the insulating sheet 120, The detection electrode leads 102A and 102B are formed, and the detection electrodes EL _A and EL _B form conductive paths that are connected in series without branching from the disconnection detection terminals 103A and 103B to the PM detection terminals 104A and 104B. Although the method has been described, the present embodiment is different in that the detection electrode folded portions 101A and 101B and the detection electrode lead portions 102A and 102B that secure conduction between the layers are formed by through-hole printing.

By adopting such a configuration, only the detection electrode layers 100A and 100B partitioned in a substantially strip shape are exposed in parallel through the insulating layer 120 on the surface of the detection unit 10d, and the detection electrode is folded back. The portions 101Ad and 101Bd and the detection electrode lead portions 102Ad and 102Bd are embedded in the insulating layer 120.
For this reason, when an electric field is applied between the detection electrodes EL _Ad and EL _Bd to collect particulate matter contained in the gas to be measured, the electric field does not concentrate on the bent portion of the detection electrode, Since a uniform electric field is formed between the detection electrodes EL _Ad and EL _Bd arranged in parallel, uneven distribution of the collected particulate matter can be suppressed, and detection accuracy can be further improved.
Further, in the present invention, the directionality of the detection units 10, 10a, 10b, 10c, and 10d is not particularly limited, and is orthogonal to the longitudinal direction of the particulate matter detection element 2 as shown in FIG. 1B. The detection electrode facing portions 100A and 100B may be formed to be aligned in the direction, or as shown in FIG. 10A, the detection electrode facing portions 100A and 100A in a direction parallel to the longitudinal direction of the particulate matter detection element 2 You may form so that 100B may be located in a line.

In the above embodiment, the thickness of the insulating layer 120 that insulates between the pair of detection electrode facing portions 100A and 100B is 20 μm or less by making the detection portions 10, 10a, 10b, 10c, and 10d have a laminated structure. However, the detection electrodes constituting the pair of detection electrodes EL _A and EL _B are connected in series from one end to the other end. And a detection electrode facing portion 100A, 100B facing each other by providing a predetermined gap, and a conduction path connected to the other end. If the sensor has a disconnection detection circuit that detects the presence or absence of disconnection in the pair of detection electrodes EL _A and EL _B by measuring the resistance value up to the part, the detection electrode facing part is thick-film printed, Thin film Printing, in which the plating, CVD, may also be applied to a case of forming by the method such as PVD.
In the case of thick film printing, since it is difficult to set the insulation distance for insulating the detection electrode facing portions to a pair of 20 μm or less, a decrease in detection accuracy is unavoidable as compared with the above embodiment, but disconnection in the detection electrode By making detection possible, it is possible to improve the reliability of the sensor.

DESCRIPTION OF SYMBOLS 1 Particulate matter detection sensor 10 Detection part 100A, 100B Detection electrode layer 101A, 101B Detection electrode folding | returning part 102A, 102B Detection electrode lead part 103A, 103B Disconnection detection terminal part 104A, 104B Particulate matter detection terminal part 105A, 105B Detection electrode Return lead part 2 Particulate matter detection element 20 Substrate part 200, 210 Insulating substrate 220 Heating element 221A, 221B Heating element lead part 222A, 222B Heating element terminal part 223A, 223B Through-hole electrode

JP 2005-164554 A JP 2012-47596 A JP 2011-203093 A

Claims (12)

The above-described detection that changes according to the amount of particulate matter collected and deposited on the detection unit (10, 10c, 10d) having a pair of detection electrodes (EL _A , EL _B ) facing each other at least at a predetermined distance A particulate matter detection sensor provided with a particulate matter detection element (2, 2, 2b, 2c, 2d) that detects electrical characteristics between electrodes and detects the amount of particulate matter contained in a gas to be measured. There,
Each detection electrode constituting the pair of detection electrodes (EL _A , EL _B )
A conduction path connected in series is formed from one end (103A, 103B, 103Ac, 103Bc, 103Ad, 103Bd) to the other end (104A, 104B, 104Ac, 104Bc, 104Ad, 104Bd). ,
A folded portion (101A, 101B, 101Ad, 101Bd) that is partially bent;
Detection electrode facing portions (100A, 100B) facing each other through an insulating layer (120) that forms a predetermined distance between the detection electrodes,
By measuring the resistance value from the one end (103A, 103B, 103Ac, 103Bc, 103Ad, 103Bd) to the other end (104A, 104B, 104Ac, 104Bc, 104Ad, 104Bd), Particulate matter detection sensor (1) comprising a disconnection detection circuit (301A, 301Aa, 301Ab, 301B, 301Ba, 301Bb) for detecting the presence or absence of disconnection in the detection electrodes (EL _A , EL _B ) 1a, 1b, 1c, 1d).   Resistance, capacitance, impedance between the one end (103A-103B, 103Ac-103Bc, 103Ad-103Bd) or between the other end (104A-104B, 104Ac-104Bc, 104Ad-104Bd) 2. The particulate matter detection sensor (1, 1 a, 1 b) according to claim 1, further comprising a PM detection circuit unit (31) that detects a deposition amount of the particulate matter deposited between the detection electrodes. 1c, 1d). The particulate matter detection element (2, 2b, 2c, 2d)
The detection unit (10, 10c, 10d);
The board portion (20, 20b, 20c, 20d) on which this is mounted,
The detection unit (10, 10c, 10d)
The detection electrode facing portion (100A, 100B) formed in a substantially flat plate shape with a film thickness of 100 μm or more and 500 μm or less;
The particulate matter detection sensor (1, 1a) according to claim 1 or 2, comprising a laminated structure in which the insulating layer (120) formed in a substantially flat shape with a film thickness of 5 µm or more and 20 µm or less is repeatedly laminated. 1b, 1c, 1d). The particulate matter detection element (2, 2b, 2c, 2d)
The particulate matter detection sensor (1, 1a, 1b, 1c, 1d) according to any one of claims 1 to 3, comprising a resistance heating element (EL _A , EL _B / 220) that generates heat when energized. The disconnection detection circuit (301Aa, 301Ba)
While measuring the DC resistance from the one end (103A, 103B) to the other end (104A, 104B) to detect the presence or absence of disconnection,
_A heat generation control circuit unit that calculates a heat generation temperature of the heating element (EL _A , EL _B / 220) from the detected DC resistance value and controls energization to the resistance heating element (EL _A , EL _B / 220) The particulate matter detection sensor (1a, 1b) according to claim 4, which has a function as: The substrate part (20) is
The particulate matter detection sensor (1, 1a, 1c, 1d) according to claim 4, comprising a substantially flat insulating substrate (200, 210) and the resistance heating element (220) therein. The disconnection detection circuit (301Ab, 301Bb)
While measuring the DC resistance from the one end (103A, 103B) to the other end (104A, 104B) to detect the presence or absence of disconnection,
Using each of the pair of detection electrodes (EL _A , EL _B ) as the resistance heating element,
By energization between the one end (103A, 103B) and the other end (104A, 104B),
The particulate matter detection sensor (1b) according to claim 4, further comprising a heat generation control circuit unit that generates heat from the pair of detection electrodes (EL _A , EL _B ). The pair of detection electrodes (EL _A , EL _B ) are LNF (LaNi _0.6 Fe _0.4 O ₃ ), LSN (La _1.2 Sr _0.8 NiO ₄ ), LSM (La _1-X Sr _{X MnO 3-δ), LSC (} La 1-X Sr X CoO 3-δ), LCC (La 1-X Ca X CrO 3-δ), LSCN (La 0.85 Sr 0.15 Cr 1-X Ni X O _3−δ ) (0.1 ≦ X ≦ 0.7) selected from any one of perovskite type conductive oxide materials and having a conductivity of 10 ⁻² S / cm or more. The particulate matter detection sensor (1, 1a, 1b, 1c, 1d) according to any one of claims 1 to 7. The insulating layer (120) has an insulating property selected from any of partially stabilized zirconia, MgO, and Al ₂ O ₃ typified by 8YSZ ((ZrO ₂ ) _0.92 (Y ₂ O ₃ ) _0.08 ) The particulate matter detection sensor (1, 1a, 1b, 1c, 1d) according to any one of claims 1 to 7, which is an insulating oxide made of an oxide material and having an electrical conductivity of 10 ^-5 S / cm or less. 10. The particulate matter in the gas to be measured is detected by an electrical characteristic that changes in accordance with the amount of particulate matter deposited between a pair of detection electrodes facing each other with a predetermined gap therebetween. A method for producing a particulate matter detection element (2, 2b, 2c, 2d) used in the particulate matter detection sensor (1, 1a, 1b, 1c, 1d) according to claim 1,
at least,
LNF (LaNi _0.6 Fe _0.4 O ₃ ), LSN (La _1.2 Sr _0.8 NiO ₄ ), LSM (La _1-X Sr _X MnO _3-δ ), LSC (La _1-X Sr _X CoO _3−δ ), LCC (La _1−X Ca _X CrO _3−δ ), LSCN (La _0.85 Sr _0.15 Cr _1−X Ni _X O _3−δ ) (0.1 ≦ X ≦ 0. 7) Conductivity for forming the substantially flat plate-shaped detection electrode facing portion (100A, 100B) having a film thickness of 100 μm or more and 500 μm or less using a perovskite type conductive oxide material selected from any one of 7) Sheet forming process;
Using an insulating oxide material selected from any of partially stabilized zirconia, MgO, and Al ₂ O ₃ typified by 8YSZ ((ZrO ₂ ) _0.92 (Y ₂ O ₃ ) _0.08 ), 5 μm Insulating sheet forming the substantially flat insulating layer (120) having a film thickness of 20 μm or less and / or insulating sheet forming to form the insulating sheet, and / or insulating sheet forming step,
A laminating step of laminating the obtained conductive sheet (100) and the insulating sheet (120) to form the detection section (10, 10c, 10d);
A method for producing a particulate matter detection element, comprising:   The particulate matter according to claim 10, further comprising a step of embedding the insulating sheet (120) partitioned into a predetermined shape at a predetermined position in the conductive sheet (100). A method for manufacturing a detection element.   The particle according to claim 10 or 11, further comprising a conductive sheet insulating sheet embedding molding step of embedding the conductive sheet (100) partitioned into a predetermined shape at a predetermined position in the insulating sheet (120). Manufacturing method of particulate matter detection element.

Images