WO2020208931A1 - Sulfidation detection resistor - Google Patents
Sulfidation detection resistor Download PDFInfo
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- WO2020208931A1 WO2020208931A1 PCT/JP2020/005320 JP2020005320W WO2020208931A1 WO 2020208931 A1 WO2020208931 A1 WO 2020208931A1 JP 2020005320 W JP2020005320 W JP 2020005320W WO 2020208931 A1 WO2020208931 A1 WO 2020208931A1
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- sulfurization
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N17/00—Investigating resistance of materials to the weather, to corrosion, or to light
- G01N17/04—Corrosion probes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C1/00—Details
- H01C1/02—Housing; Enclosing; Embedding; Filling the housing or enclosure
- H01C1/034—Housing; Enclosing; Embedding; Filling the housing or enclosure the housing or enclosure being formed as coating or mould without outer sheath
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C1/00—Details
- H01C1/14—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors
- H01C1/142—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors the terminals or tapping points being coated on the resistive element
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C13/00—Resistors not provided for elsewhere
- H01C13/02—Structural combinations of resistors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
Definitions
- the present invention relates to a sulfurization detection resistor for detecting the cumulative amount of sulfurization in a corrosive environment.
- Ag (silver) -based electrode materials with low resistivity are used as internal electrodes of electronic components such as chip resistors, but silver becomes silver sulfide when exposed to sulfide gas, and silver sulfide. Since is an insulator, there is a problem that the electronic component is broken. Therefore, in recent years, sulfurization measures have been taken such as adding Pd (palladium) or Au (gold) to Ag to form an electrode that is difficult to sulfurize, or making the electrode a structure that is difficult for sulfurized gas to reach.
- the sulfurization detection sensor described in Patent Document 1 forms a sulfurization detector mainly composed of Ag on an insulating substrate, and forms a transparent and sulfide gas permeable protective film so as to cover the sulfurization detector.
- the end face electrodes connected to the sulfurization detector are formed on both side ends of the insulating substrate.
- the sulfide gas permeates the protective film of the sulfide detection sensor and comes into contact with the sulfide detector, the volume of silver constituting the sulfide detector decreases according to the concentration of the sulfide gas and the elapsed time. Therefore, the degree of sulfurization can be detected by detecting the change in the resistance value of the sulfurization detector or the disconnection.
- a sulfurization detector is covered with a sulfurization gas permeable protective film and a sulfurization gas impermeable protective film, and these are arranged side by side in a direction orthogonal to the direction between electrodes.
- the sensor is disclosed.
- the sulfurization detection sensor configured in this way, even if the sulfurization detector in the region covered with the sulfurization gas permeable protective film is broken by sulfurization, the sulfurization detection in the region covered with the sulfurization gas impermeable protective film is detected.
- the body does not sulfide, and then the sulfide detector covered with the sulfide gas impermeable protective film gradually sulfides due to the sulfide gas that invades laterally (width direction) from the boundary between the two protective films.
- the resistance value gradually increases in the state where the conduction state is secured, so by measuring the resistance value, Since the degree of sulfurization can be detected, and the progress of sulfurization in the lateral direction is particularly slow, it is a sulfurization detection sensor suitable for detecting sulfurization over a long period of time.
- the sulfurization detector is a conductor mainly composed of Ag having a low specific resistance
- the change in the resistance value of the sulfurization detector with the cumulative amount of sulfurization is extremely small, and Ag has a temperature characteristic (TCR). Since it is very bad and the resistance value changes greatly with temperature, it is difficult to accurately detect the degree of sulfurization based on the resistance value change of the sulfurization detector.
- TCR temperature characteristic
- a sulfurization detection sensor configured to cover the sulfurization detector with two types of protective films, sulfide gas permeable and sulfurization gas impermeable, in the width direction, the formation positions of both protective films due to printing misalignment or the like.
- the present invention has been made in view of the actual situation of such a prior art, and an object of the present invention is to provide a sulfurization detection resistor capable of accurately detecting the degree of sulfurization.
- the sulfurization detection resistor of the present invention comprises a rectangular body-shaped insulating substrate, a sulfurizable sulfurization detection conductor provided on the surface of the insulating substrate, and a longitudinal direction on the back surface of the insulating substrate.
- a pair of back electrodes provided at both ends, a resistor connecting the pair of back electrodes, a protective film covering the resistor, and both ends in the longitudinal direction of the sulfide detection conductor and the back electrode are conductive.
- a pair of end face electrodes, a pair of external electrodes covering the end face electrodes and the back electrode, and both ends in the longitudinal direction of the sulfurization detection conductor are covered with the pair of the external electrodes, and the pair of the external electrodes
- the sulfide detection conductor in the region not covered with is a sulfide detection portion that can come into contact with the sulfide gas.
- the sulfide detection conductor having the sulfide detection portion and the resistor covered with the protective film are separately provided on both the front and back surfaces of the insulating substrate, so that the surface side of the insulating substrate is provided. It is possible to accurately detect that the sulfide detection part of the sulfide detection conductor provided in the above is broken by the resistance value of the current flowing through the resistor provided on the back surface side of the insulating substrate, and the sulfide detection conductor is broken. It is possible to ensure the continuity between the external electrodes even in this state.
- the height dimension from the back surface of the insulating substrate to the protective film is set to be smaller than the height dimension from the back surface of the insulating substrate to the external electrode covering the back electrode.
- the sulfurization detection portion of the sulfurization detection conductor may be directly exposed to the outside from between the pair of external electrodes, but the sulfurization detection portion is covered with a sulfurization gas permeable protective film.
- the sulfurization detection unit is less susceptible to external contact, and external electrodes can be easily plated on both ends of the sulfurization detection conductor excluding the sulfurization detection unit.
- FIG. 1 is a plan view of the sulfurization detection resistor according to the embodiment of the present invention
- FIG. 2 is a back view of the sulfurization detection resistor
- FIG. It is sectional drawing which follows the line III-III of FIG.
- the sulfide detection resistor 100 includes a rectangular-shaped insulating substrate 1, a sulfide detection conductor 2 provided on the surface of the insulation substrate 1, and the sulfide detection conductor.
- a first protective film 3 provided in the central portion of 2, a pair of back electrodes 4 provided at both ends in the longitudinal direction of the back surface of the insulating substrate 1, a resistor 5 connecting between the back electrodes 4, and a resistor thereof.
- a second protective film 6 that covers the body 5, a pair of end face electrodes 7 provided on both end faces in the longitudinal direction of the insulating substrate 1, and a pair of outer surfaces that cover both ends of the sulfurization detection conductor 2, end face electrodes 7, and back electrodes 4. It is mainly composed of an electrode 8.
- the insulating substrate 1 is obtained by dividing a large-format substrate, which will be described later, along vertical and horizontal dividing grooves and taking a large number of them, and the main component of the large-format substrate is a ceramic substrate containing alumina as a main component.
- the sulfide detection conductor 2 is obtained by screen-printing an Ag paste containing silver as a main component, drying and firing, and the sulfide detection conductor 2 is formed on the surface of the insulating substrate 1. Both ends of the sulfurization detection conductor 2 in the longitudinal direction are covered with external electrodes 8 that block the permeation of the sulfurization gas, but the central portion of the sulfurization detection conductor 2 is a sulfurization detection portion 2a that can come into contact with the sulfurization gas.
- the first protective film 3 is made of a sulfide gas permeable insulating material, and is obtained by screen-printing a resin paste such as a silicone resin or a fluororesin and heat-curing it.
- the first protective film 3 is formed so as to cover the sulfurization detection portion 2a of the sulfurization detection conductor 2, and the sulfurization gas permeates through the first protective film 3 and comes into contact with the sulfurization detection portion 2a.
- the sulfurization detection resistor 100 is mounted on the circuit board and used for detecting the sulfurization gas
- the sulfurization detection unit 2a is covered with the first protective film 3, so that the sulfurization detection unit 2a is used. It is less susceptible to external contact.
- the back electrode 4 has a two-layer structure consisting of a first back electrode 4a formed on the back surface of the insulating substrate 1 and a second back electrode 4b laminated on the first back electrode 4a, and has a total height.
- a thick back electrode 4 is configured.
- the first back electrode 4a is made of calcined silver obtained by screen-printing an Ag-based paste containing silver as a main component, drying and firing, and the second back electrode 4b is screen-printed and heated by an Ag paste containing silver as a main component. It consists of hardened resin silver.
- the resistor 5 is made by screen-printing a resistor paste such as ruthenium oxide, drying and firing, and both ends of the resistor 5 overlap the first back electrode 4a.
- the second protective film 6 has a two-layer structure of an undercoat layer 6a and an overcoat layer 6b, and the second back electrode 4b overlaps both ends of the second protective film 6.
- the undercoat layer 6a is a glass paste screen-printed and dried / fired
- the overcoat layer 6b is an epoxy-based resin paste screen-printed and heat-cured.
- the undercoat layer 6a and the overcoat layer 6b are made of an insulating material that blocks the permeation of sulfide gas, and the entire resistor 5 is covered with such a second protective film 6.
- the end face electrode 7 is obtained by sputtering Ni / Cr on the end face of the insulating substrate 1 or applying an Ag-based paste and heat-curing the end face electrode 7.
- the end face electrode 7 corresponds to both ends of the sulfurization detection conductor 2 in the longitudinal direction and the corresponding ends. It is formed so as to be conductive with the back electrode 4.
- the external electrode 8 has a two-layer structure consisting of a barrier layer and an external connection layer, of which the barrier layer is a Ni plating layer formed by electrolytic plating, and the external connection layer is a Sn plating layer formed by electrolytic plating.
- the external electrode 8 both ends of the sulfurization detection conductor 2 exposed from the first protective film 3 and the surfaces of the end face electrode 7 and the back electrode 4 are covered in a U-shaped cross section.
- the second back electrode 4b is a back electrode 4 having a thick film structure that protrudes downward with respect to the surface height of the overcoat layer 6b, and the external electrode 8 covers such a second back electrode 4b. Therefore, the height dimension from the back surface of the insulating substrate 1 to the overcoat layer 6b is smaller than the height dimension from the back surface of the insulating substrate 1 to the external electrode 8 covering the second back electrode 4b.
- FIGS. 4 (a) to 4 (h) are plan views of the large format substrate used in this manufacturing process
- FIGS. 5 (a) to 5 (h) are back views of the large format substrate
- FIGS. 6 (a) to 6 (h) are shown.
- 4 (a) to 4 (h) show cross-sectional views corresponding to one chip along the central portion in the longitudinal direction.
- the large-format substrate is provided with a primary dividing groove and a secondary dividing groove in a grid pattern in advance, and each of the squares divided by both dividing grooves serves as a chip area for one piece.
- the large-format substrate corresponding to one chip region is represented in FIGS. 4 to 6, each step described below is actually performed for the large-format substrate corresponding to a large number of chip regions. It is done all at once.
- an Ag-based paste (Ag-Pd 20%) was screen-printed on the back surface of the large-format substrate 10A, and then dried. It is fired to form a pair of first back electrodes 4a.
- an Ag paste containing silver as a main component is screen-printed on the surface of the large-format substrate 10A, dried and baked.
- a rectangular sulfide detection conductor 2 is formed on the surface of the large-format substrate 10A. Both ends of the sulfide detection conductor 2 in the longitudinal direction extend to a position reaching the short side of the large format substrate 10A, but the dimension of the sulfide detection conductor 2 in the lateral direction is slightly larger than the short side length of the large format substrate 10A. It is set short.
- a resistor paste such as ruthenium oxide was screen-printed on the back surface of the large-format substrate 10A, dried and fired, as shown in FIGS. 4 (c), 5 (c) and 6 (c).
- a resistor 5 having both ends overlapping the first back electrode 4a is formed.
- the glass paste is dried and fired to form an undercoat layer 6a, and if necessary, the resistor 5 is formed from above the undercoat layer 6a.
- a trimming groove (not shown) is formed to adjust the resistance value.
- the epoxy resin paste is screen-printed on the undercoat layer 6a and heat-cured to form the overcoat layer 6b, whereby FIGS. 4 (d), 5 (d) and 6 (D) and FIG. As shown in d), a second protective film 6 having a two-layer structure covering the entire resistor 5 is formed.
- a resin paste such as a silicone resin or a fluororesin is screen-printed on the central portion of the sulfide detection conductor 2, and this is heat-cured to form as shown in FIGS. 3 (f) and 4 (f).
- a sulfide gas permeable first protective film 3 that covers the central portion of the sulfide detection conductor 2 is formed.
- the large-format substrate 10A is first divided into strip-shaped substrates 10B along the primary dividing groove, and then Ni / Cr is sputtered on the divided surfaces of the strip-shaped substrate 10B to show FIGS. 4 (g) and 5 (g).
- a pair of end face electrodes 7 connecting the sulfurization detection conductor 2 and the back electrode 4 are formed.
- the end face electrode 7 may be formed by applying an Ag-based paste and heat-curing it.
- the strip-shaped substrate 10B is secondarily divided into a plurality of chip-shaped substrates 10C along the secondary dividing groove, and the chip-shaped substrates 10C are electrolytically plated to sequentially form a Ni plating layer and a Sn plating layer.
- the chip-shaped substrates 10C are electrolytically plated to sequentially form a Ni plating layer and a Sn plating layer.
- both ends of the sulfurization detection conductor 2 except the central portion are covered with the sulfur gas impermeable external electrode 8, and the central portion of the sulfurization detection conductor 2 excluding the region covered with the first protective film 3 is sulfurized gas.
- the sulfurization detection resistor 100 shown in FIGS. 1 to 3 is completed with the sulfurization detection unit 2a that can come into contact with
- the sulfurization detection resistor 100 configured in this way is mounted on the circuit board 11 together with other electronic components (not shown), and then the circuit board 11 is exposed to an atmosphere containing sulfur gas. Used by At that time, the sulfide detection resistor 100 is mounted on the circuit board 11 in a posture in which the surface side of the insulating substrate 1 on which the sulfide detection conductor 2 is formed faces upward (that is, a posture in which the resistor 5 faces downward). However, since the overcoat layer 6b of the second protective film 6 is arranged in a stepped manner between the pair of external electrodes 8 covering the back electrode 4, there is a step between the second protective film 6 and the circuit board 11. A considerable amount of gap is secured.
- the sulfurization detection resistor 100 can be mounted on the circuit board 11 in a stable posture, and the wiring pattern 12 provided on the surface of the circuit board 11 and the external electrode 8 of the sulfurization detection resistor 100 can be easily mounted. Moreover, it can be reliably joined with the solder 13.
- the sulfurization detection resistor 100 mounted on the circuit board 11 When the sulfurization detection resistor 100 mounted on the circuit board 11 is exposed to the sulfurization gas in this way, the sulfurization gas permeates through the first protective film 3 and comes into contact with the sulfurization detection portion 2a of the sulfurization detection conductor 2. As the cumulative amount of sulfurization increases over time, the sulfurization detection unit 2a breaks inside the first protective film 3, and at this point, the degree of sulfurization is accurately detected by the resistance value of the current flowing through the resistor 5. can do. Moreover, even if the sulfide detection conductor 2 provided on the front surface side of the insulating substrate 1 is disconnected, the resistor 5 provided on the back surface side of the insulating substrate 1 is not sulfided, so that between the pair of external electrodes 8. Conduction can be ensured by the resistor 5.
- the sulfide detection conductor 2 having the sulfide detection portion 2a and the resistor 5 covered with the second protective film 6 are both front and back surfaces of the insulating substrate 1.
- a resistor provided on the back surface side of the insulating substrate 1 that the sulfide detecting portion 2a of the sulfide detecting conductor 2 provided on the front surface side of the insulating substrate 1 was broken due to cumulative sulfide. It can be accurately detected by the resistance value of the current flowing through the body 5, and moreover, the conduction between the external electrodes 8 can be ensured even if the sulfide detection conductor 2 is disconnected.
- the height dimension from the back surface of the insulating substrate 1 to the second protective film 6 is the height from the back surface of the insulating substrate 1 to the external electrode 8 covering the back electrode 4.
- the size is smaller than the size, and the second protective film 6 is arranged in a stepped-down shape in the region sandwiched between the pair of external electrodes 8 covering the back electrode 4, so that the sulfurization detection conductor 2 When mounted on the circuit board 11 in a posture in which the front surface side of the insulating substrate 1 formed with the above is facing upward, both are placed between the second protective film 6 formed on the back surface side of the insulating substrate 1 and the circuit board 11.
- the back electrode 4 has a laminated structure (two-layer structure) of the first back electrode 4a formed on the back surface of the insulating substrate 1 and the second back electrode 4b laminated on the first back electrode 4a. Therefore, the back electrode 4 having a large height can be easily formed.
- the sulfurization detection unit 2a of the sulfurization detection conductor 2 is covered with the first protective film 3 that is permeable to sulfurization gas, the sulfurization detection unit 2a is from the outside.
- external electrodes 8 can be easily plated on both ends of the sulfurization detection conductor 2 excluding the sulfurization detection portion 2a.
- the electrode 8 may be plated, and after the external electrode 8 is plated, the resist film may be peeled off and removed with a solvent to expose the sulfide detection unit 2a.
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Abstract
Provided is a sulfidation detection resistor that can accurately detect degree of sulfidation. A sulfidation detection resistor (100) that comprises a rectangular insulating substrate (1), a sulfidation detection conductor (2) that is provided on the surface of the insulating substrate (1), a pair of rear electrodes (4) that are provided at either longitudinal-direction end part of a rear surface of the insulating substrate (1), a resistor (5) that connects the pair of rear electrodes (4), a second protection layer (6) that covers the resistor (5), a pair of end surface electrodes (7) that electrically connect either end of the sulfidation detection conductor (2) and the rear electrodes (4), and a pair of outer electrodes (8) that cover either longitudinal-direction end part of the sulfidation detection conductor (2), the end surface electrodes (7), and the rear electrodes (4). A center part of the sulfidation detection conductor (2) that is not covered by the pair of outer electrodes (8) is a sulfidation detection part (2a) that can contact sulfidizing gas.
Description
本発明は、腐食環境の累積的な硫化量を検出するための硫化検出抵抗器に関する。
The present invention relates to a sulfurization detection resistor for detecting the cumulative amount of sulfurization in a corrosive environment.
一般的にチップ抵抗器等の電子部品の内部電極としては、比抵抗の低いAg(銀)系の電極材料が使用されているが、銀は硫化ガスに曝されると硫化銀となり、硫化銀は絶縁物であることから、電子部品が断線してしまうという不具合が発生してしまう。そこで近年では、AgにPd(パラジウム)やAu(金)を添加して硫化しにくい電極を形成したり、電極を硫化ガスが到達しにくい構造にする等の硫化対策が講じられている。
Generally, Ag (silver) -based electrode materials with low resistivity are used as internal electrodes of electronic components such as chip resistors, but silver becomes silver sulfide when exposed to sulfide gas, and silver sulfide. Since is an insulator, there is a problem that the electronic component is broken. Therefore, in recent years, sulfurization measures have been taken such as adding Pd (palladium) or Au (gold) to Ag to form an electrode that is difficult to sulfurize, or making the electrode a structure that is difficult for sulfurized gas to reach.
しかし、このような硫化対策を電子部品に講じたとしても、当該電子部品が硫化ガス中に長期間曝された場合や高濃度の硫化ガスに曝された場合は、断線を完全に防ぐことが難しくなるため、未然に断線を検知して予期せぬタイミングでの故障発生を防止することが必要となる。
However, even if such sulfurization measures are taken for electronic components, disconnection can be completely prevented when the electronic components are exposed to sulfurized gas for a long period of time or exposed to high-concentration sulfurized gas. Since it becomes difficult, it is necessary to detect the disconnection in advance and prevent the occurrence of failure at an unexpected timing.
そこで従来より、特許文献1に記載されているように、電子部品の累積的な硫化の度合いを検出して、電子部品が硫化断線する等して故障する前に危険性を検出可能とした硫化検出センサが提案されている。
Therefore, conventionally, as described in Patent Document 1, sulfurization that can detect the degree of cumulative sulfurization of an electronic component and detect the risk before the electronic component fails due to sulfurization disconnection or the like. Detection sensors have been proposed.
特許文献1に記載された硫化検出センサは、絶縁基板上にAgを主体とした硫化検出体を形成し、この硫化検出体を覆うように透明で硫化ガス透過性のある保護膜を形成すると共に、絶縁基板の両側端部に硫化検出体に接続する端面電極を形成した構成となっている。このように構成された硫化検出センサを他の電子部品と共に回路基板上に実装した後、該回路基板を硫化ガスを含む雰囲気で使用すると、時間経過に伴って他の電子部品が硫化されると共に、硫化ガスが硫化検出センサの保護膜を透過して硫化検出体に接するため、硫化ガスの濃度と経過時間に応じて硫化検出体を構成する銀の体積が減少していく。したがって、硫化検出体の抵抗値の変化や断線を検出することにより、硫化の度合いを検出することができる。
The sulfurization detection sensor described in Patent Document 1 forms a sulfurization detector mainly composed of Ag on an insulating substrate, and forms a transparent and sulfide gas permeable protective film so as to cover the sulfurization detector. , The end face electrodes connected to the sulfurization detector are formed on both side ends of the insulating substrate. When the sulfurization detection sensor configured in this way is mounted on a circuit board together with other electronic components and then used in an atmosphere containing sulfurized gas, the other electronic components are sulfurized with the passage of time. Since the sulfide gas permeates the protective film of the sulfide detection sensor and comes into contact with the sulfide detector, the volume of silver constituting the sulfide detector decreases according to the concentration of the sulfide gas and the elapsed time. Therefore, the degree of sulfurization can be detected by detecting the change in the resistance value of the sulfurization detector or the disconnection.
また、特許文献1には、硫化検出体を硫化ガス透過性の保護膜と硫化ガス非透過性の保護膜とで覆い、これらを電極間方向と直交する方向に並設させた構成の硫化検出センサが開示されている。このように構成された硫化検出センサでは、硫化ガス透過性保護膜で覆われた領域の硫化検出体が硫化によって断線されたとしても、硫化ガス非透過性保護膜で覆われた領域の硫化検出体は硫化せず、その後に、硫化ガス非透過性保護膜で覆われた硫化検出体が両保護膜の境界から横方向(幅方向)に侵入する硫化ガスによって徐々に硫化していく。これにより、硫化ガス透過性保護膜で覆われた領域が硫化により断線した場合でも、導通状態が確保されている状態では徐々に抵抗値が上昇していくため、その抵抗値を測定することによって硫化の度合いを検出することができ、特に、横方向の硫化の進行は遅いので、長期間にわたる硫化の検出に好適な硫化検出センサとなっている。
Further, in Patent Document 1, a sulfurization detector is covered with a sulfurization gas permeable protective film and a sulfurization gas impermeable protective film, and these are arranged side by side in a direction orthogonal to the direction between electrodes. The sensor is disclosed. With the sulfurization detection sensor configured in this way, even if the sulfurization detector in the region covered with the sulfurization gas permeable protective film is broken by sulfurization, the sulfurization detection in the region covered with the sulfurization gas impermeable protective film is detected. The body does not sulfide, and then the sulfide detector covered with the sulfide gas impermeable protective film gradually sulfides due to the sulfide gas that invades laterally (width direction) from the boundary between the two protective films. As a result, even if the region covered with the sulfide gas permeable protective film is broken due to sulfurization, the resistance value gradually increases in the state where the conduction state is secured, so by measuring the resistance value, Since the degree of sulfurization can be detected, and the progress of sulfurization in the lateral direction is particularly slow, it is a sulfurization detection sensor suitable for detecting sulfurization over a long period of time.
しかし、硫化検出体が比抵抗の低いAgを主体とした導電体であるため、累積的な硫化量に伴う硫化検出体の抵抗値変化は極めて微量であり、しかもAgは温度特性(TCR)が非常に悪く、温度による抵抗値変化が大きいため、硫化検出体の抵抗値の変化に基づいて硫化の度合いを正確に検出することは困難となる。また、硫化検出体を硫化ガス透過性と硫化ガス非透過性の2種類の保護膜で幅方向に覆うように構成した硫化検出センサの場合、印刷ズレ等に起因して両保護膜の形成位置がばらつき易くなるため、硫化ガス透過性保護膜で覆われた硫化検出体が断線するタイミングや、硫化ガス非透過性保護膜で覆われた硫化検出体の抵抗値変化率が製品毎にばらついてしまい、検出精度の個体差が大きいという問題もある。
However, since the sulfurization detector is a conductor mainly composed of Ag having a low specific resistance, the change in the resistance value of the sulfurization detector with the cumulative amount of sulfurization is extremely small, and Ag has a temperature characteristic (TCR). Since it is very bad and the resistance value changes greatly with temperature, it is difficult to accurately detect the degree of sulfurization based on the resistance value change of the sulfurization detector. Further, in the case of a sulfurization detection sensor configured to cover the sulfurization detector with two types of protective films, sulfide gas permeable and sulfurization gas impermeable, in the width direction, the formation positions of both protective films due to printing misalignment or the like. The timing of disconnection of the sulfurized detector covered with the sulfurized gas permeable protective film and the rate of change in the resistance value of the sulfurized detector covered with the sulfurized gas impermeable protective film vary from product to product. Therefore, there is also a problem that individual differences in detection accuracy are large.
本発明は、このような従来技術の実情に鑑みてなされたもので、その目的は、硫化の度合いを正確に検出することができる硫化検出抵抗器を提供することにある。
The present invention has been made in view of the actual situation of such a prior art, and an object of the present invention is to provide a sulfurization detection resistor capable of accurately detecting the degree of sulfurization.
上記の目的を達成するために、本発明の硫化検出抵抗器は、直方体形状の絶縁基板と、前記絶縁基板の表面に設けられた硫化可能な硫化検出導体と、前記絶縁基板の裏面における長手方向両端部に設けられた一対の裏電極と、一対の前記裏電極間を接続する抵抗体と、前記抵抗体を覆う保護膜と、前記硫化検出導体の長手方向両端部と前記裏電極を導通する一対の端面電極と、前記端面電極と前記裏電極を覆う一対の外部電極と、を備え、前記硫化検出導体の長手方向両端部が一対の前記外部電極によって覆われており、一対の前記外部電極で覆われていない領域の前記硫化検出導体が硫化ガスと接触可能な硫化検出部になっていることを特徴としている。
In order to achieve the above object, the sulfurization detection resistor of the present invention comprises a rectangular body-shaped insulating substrate, a sulfurizable sulfurization detection conductor provided on the surface of the insulating substrate, and a longitudinal direction on the back surface of the insulating substrate. A pair of back electrodes provided at both ends, a resistor connecting the pair of back electrodes, a protective film covering the resistor, and both ends in the longitudinal direction of the sulfide detection conductor and the back electrode are conductive. A pair of end face electrodes, a pair of external electrodes covering the end face electrodes and the back electrode, and both ends in the longitudinal direction of the sulfurization detection conductor are covered with the pair of the external electrodes, and the pair of the external electrodes The sulfide detection conductor in the region not covered with is a sulfide detection portion that can come into contact with the sulfide gas.
このように構成された硫化検出抵抗器では、硫化検出部を有する硫化検出導体と保護膜で覆われた抵抗体とが絶縁基板の表裏両面に振り分けて設けられているため、絶縁基板の表面側に設けられた硫化検出導体の硫化検出部が断線したことを、絶縁基板の裏面側に設けられた抵抗体を流れる電流の抵抗値によって正確に検出することができ、しかも、硫化検出導体が断線した状態になっても外部電極間の導通を確保することができる。
In the sulfide detection resistor configured in this way, the sulfide detection conductor having the sulfide detection portion and the resistor covered with the protective film are separately provided on both the front and back surfaces of the insulating substrate, so that the surface side of the insulating substrate is provided. It is possible to accurately detect that the sulfide detection part of the sulfide detection conductor provided in the above is broken by the resistance value of the current flowing through the resistor provided on the back surface side of the insulating substrate, and the sulfide detection conductor is broken. It is possible to ensure the continuity between the external electrodes even in this state.
上記構成の硫化検出抵抗器において、絶縁基板の裏面から保護膜までの高さ寸法が、絶縁基板の裏面から裏電極を覆う外部電極までの高さ寸法に比べて小さくなるように設定されていると、硫化検出導体が形成された絶縁基板の表面側を上向きにした姿勢で回路基板に実装した際に、絶縁基板の裏面側に形成された保護膜と回路基板との間に隙間が確保されるため、硫化検出抵抗器を安定した姿勢で回路基板上に実装することができる。この場合において、裏電極が、絶縁基板の裏面上に形成された第1裏電極と、該第1裏電極上に積層された第2裏電極とを含んでいると、高さ寸法の厚い裏電極を容易に形成することができて好ましい。
In the sulfurization detection resistor having the above configuration, the height dimension from the back surface of the insulating substrate to the protective film is set to be smaller than the height dimension from the back surface of the insulating substrate to the external electrode covering the back electrode. When mounted on the circuit board with the front side of the insulating substrate on which the sulfurization detection conductor is formed facing upward, a gap is secured between the protective film formed on the back surface side of the insulating substrate and the circuit board. Therefore, the sulfurization detection resistor can be mounted on the circuit board in a stable posture. In this case, if the back electrode includes a first back electrode formed on the back surface of the insulating substrate and a second back electrode laminated on the first back electrode, a back electrode having a large height dimension is provided. It is preferable that the electrode can be easily formed.
また、上記構成の硫化検出抵抗器において、硫化検出導体の硫化検出部は一対の外部電極間から外部に直接露出しても良いが、硫化検出部が硫化ガス透過性保護膜によって覆われていると、硫化検出部が外部からの接触の影響を受け難くなり、硫化検出部を除く硫化検出導体の両端部に外部電極を容易にめっき形成することができる。
Further, in the sulfurization detection resistor having the above configuration, the sulfurization detection portion of the sulfurization detection conductor may be directly exposed to the outside from between the pair of external electrodes, but the sulfurization detection portion is covered with a sulfurization gas permeable protective film. As a result, the sulfurization detection unit is less susceptible to external contact, and external electrodes can be easily plated on both ends of the sulfurization detection conductor excluding the sulfurization detection unit.
本発明によれば、硫化の度合いを正確に検出することが可能な硫化検出抵抗器を提供することができる。
According to the present invention, it is possible to provide a sulfurization detection resistor capable of accurately detecting the degree of sulfurization.
以下、発明の実施の形態について図面を参照しながら説明すると、図1は本発明の実施形態例に係る硫化検出抵抗器の平面図、図2は該硫化検出抵抗器の裏面図、図3は図1のIII-III線に沿う断面図である。
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of the sulfurization detection resistor according to the embodiment of the present invention, FIG. 2 is a back view of the sulfurization detection resistor, and FIG. It is sectional drawing which follows the line III-III of FIG.
図1~図3に示すように、本実施形態例に係る硫化検出抵抗器100は、直方体形状の絶縁基板1と、絶縁基板1の表面に設けられた硫化検出導体2と、この硫化検出導体2の中央部に設けられ第1保護膜3と、絶縁基板1の裏面の長手方向両端部に設けられた一対の裏電極4と、これら裏電極4間を接続する抵抗体5と、この抵抗体5を覆う第2保護膜6と、絶縁基板1の長手方向両端面に設けられた一対の端面電極7と、硫化検出導体2の両端部と端面電極7および裏電極4を覆う一対の外部電極8と、によって主として構成されている。
As shown in FIGS. 1 to 3, the sulfide detection resistor 100 according to the present embodiment includes a rectangular-shaped insulating substrate 1, a sulfide detection conductor 2 provided on the surface of the insulation substrate 1, and the sulfide detection conductor. A first protective film 3 provided in the central portion of 2, a pair of back electrodes 4 provided at both ends in the longitudinal direction of the back surface of the insulating substrate 1, a resistor 5 connecting between the back electrodes 4, and a resistor thereof. A second protective film 6 that covers the body 5, a pair of end face electrodes 7 provided on both end faces in the longitudinal direction of the insulating substrate 1, and a pair of outer surfaces that cover both ends of the sulfurization detection conductor 2, end face electrodes 7, and back electrodes 4. It is mainly composed of an electrode 8.
絶縁基板1は、後述する大判基板を縦横の分割溝に沿って分割して多数個取りされたものであり、大判基板の主成分はアルミナを主成分とするセラミックス基板である。
The insulating substrate 1 is obtained by dividing a large-format substrate, which will be described later, along vertical and horizontal dividing grooves and taking a large number of them, and the main component of the large-format substrate is a ceramic substrate containing alumina as a main component.
硫化検出導体2は銀を主成分とするAgペーストをスクリーン印刷して乾燥・焼成したものであり、この硫化検出導体2は絶縁基板1の表面に形成されている。硫化検出導体2の長手方向両端部は硫化ガスの透過を遮断する外部電極8によって覆われているが、硫化検出導体2の中央部は硫化ガスと接触可能な硫化検出部2aとなっている。
The sulfide detection conductor 2 is obtained by screen-printing an Ag paste containing silver as a main component, drying and firing, and the sulfide detection conductor 2 is formed on the surface of the insulating substrate 1. Both ends of the sulfurization detection conductor 2 in the longitudinal direction are covered with external electrodes 8 that block the permeation of the sulfurization gas, but the central portion of the sulfurization detection conductor 2 is a sulfurization detection portion 2a that can come into contact with the sulfurization gas.
第1保護膜3は、硫化ガス透過性の絶縁材料からなり、シリコン樹脂やフッ素樹脂等の樹脂ペースト等をスクリーン印刷して加熱硬化させたものである。第1保護膜3は硫化検出導体2の硫化検出部2aを覆うように形成されており、この第1保護膜3を透過して硫化ガスが硫化検出部2aに接触するようになっている。後述するように、硫化検出抵抗器100が回路基板に実装されて硫化ガスの検出に使用される際に、第1保護膜3によって硫化検出部2aが覆われているため、硫化検出部2aは外部からの接触の影響を受け難くなっている。
The first protective film 3 is made of a sulfide gas permeable insulating material, and is obtained by screen-printing a resin paste such as a silicone resin or a fluororesin and heat-curing it. The first protective film 3 is formed so as to cover the sulfurization detection portion 2a of the sulfurization detection conductor 2, and the sulfurization gas permeates through the first protective film 3 and comes into contact with the sulfurization detection portion 2a. As will be described later, when the sulfurization detection resistor 100 is mounted on the circuit board and used for detecting the sulfurization gas, the sulfurization detection unit 2a is covered with the first protective film 3, so that the sulfurization detection unit 2a is used. It is less susceptible to external contact.
裏電極4は、絶縁基板1の裏面上に形成された第1裏電極4aと、この第1裏電極4a上に積層された第2裏電極4bとの2層構造からなり、トータル高さの厚い裏電極4が構成されている。第1裏電極4aは銀を主成分とするAg系ペーストをスクリーン印刷して乾燥・焼成させた焼成銀からなり、第2裏電極4bは銀を主成分とするAgペーストをスクリーン印刷して加熱硬化させた樹脂銀からなる。
The back electrode 4 has a two-layer structure consisting of a first back electrode 4a formed on the back surface of the insulating substrate 1 and a second back electrode 4b laminated on the first back electrode 4a, and has a total height. A thick back electrode 4 is configured. The first back electrode 4a is made of calcined silver obtained by screen-printing an Ag-based paste containing silver as a main component, drying and firing, and the second back electrode 4b is screen-printed and heated by an Ag paste containing silver as a main component. It consists of hardened resin silver.
抵抗体5は酸化ルテニウム等の抵抗体ペーストをスクリーン印刷して乾燥・焼成させたものであり、抵抗体5の両端部は第1裏電極4aに重なっている。
The resistor 5 is made by screen-printing a resistor paste such as ruthenium oxide, drying and firing, and both ends of the resistor 5 overlap the first back electrode 4a.
第2保護膜6はアンダーコート層6aとオーバーコート層6bの2層構造からなり、この第2保護膜6の両端部に第2裏電極4bが重なっている。アンダーコート層6aはガラスペーストをスクリーン印刷して乾燥・焼成させたものであり、オーバーコート層6bはエポキシ系樹脂ペーストをスクリーン印刷して加熱硬化させたものである。これらアンダーコート層6aとオーバーコート層6bは硫化ガスの透過を遮断する絶縁材料からなり、このような第2保護膜6によって抵抗体5の全体が覆われている。
The second protective film 6 has a two-layer structure of an undercoat layer 6a and an overcoat layer 6b, and the second back electrode 4b overlaps both ends of the second protective film 6. The undercoat layer 6a is a glass paste screen-printed and dried / fired, and the overcoat layer 6b is an epoxy-based resin paste screen-printed and heat-cured. The undercoat layer 6a and the overcoat layer 6b are made of an insulating material that blocks the permeation of sulfide gas, and the entire resistor 5 is covered with such a second protective film 6.
端面電極7は、絶縁基板1の端面にNi/Crをスパッタしたり、Ag系ペーストを塗布して加熱硬化させたものであり、端面電極7は硫化検出導体2の長手方向両端部とそれに対応する裏電極4との間を導通するように形成されている。
The end face electrode 7 is obtained by sputtering Ni / Cr on the end face of the insulating substrate 1 or applying an Ag-based paste and heat-curing the end face electrode 7. The end face electrode 7 corresponds to both ends of the sulfurization detection conductor 2 in the longitudinal direction and the corresponding ends. It is formed so as to be conductive with the back electrode 4.
外部電極8はバリヤー層と外部接続層の2層構造からなり、そのうちバリヤー層は電解メッキによって形成されたNiメッキ層であり、外部接続層は電解メッキによって形成されたSnメッキ層である。この外部電極8により、第1保護膜3から露出する硫化検出導体2の両端部と端面電極7および裏電極4の表面が断面コ字状に被覆されている。ここで、第2裏電極4bがオーバーコート層6bの表面高さに対して下方に突出する厚膜構造の裏電極4となっており、このような第2裏電極4bを外部電極8が覆っているため、絶縁基板1の裏面から第2裏電極4bを覆う外部電極8に至る高さ寸法に比べると、絶縁基板1の裏面からオーバーコート層6bに至る高さ寸法は小さくなっている。
The external electrode 8 has a two-layer structure consisting of a barrier layer and an external connection layer, of which the barrier layer is a Ni plating layer formed by electrolytic plating, and the external connection layer is a Sn plating layer formed by electrolytic plating. By the external electrode 8, both ends of the sulfurization detection conductor 2 exposed from the first protective film 3 and the surfaces of the end face electrode 7 and the back electrode 4 are covered in a U-shaped cross section. Here, the second back electrode 4b is a back electrode 4 having a thick film structure that protrudes downward with respect to the surface height of the overcoat layer 6b, and the external electrode 8 covers such a second back electrode 4b. Therefore, the height dimension from the back surface of the insulating substrate 1 to the overcoat layer 6b is smaller than the height dimension from the back surface of the insulating substrate 1 to the external electrode 8 covering the second back electrode 4b.
次に、この硫化検出抵抗器100の製造工程について、図4~図6を用いて説明する。なお、図4(a)~(h)はこの製造工程で用いられる大判基板の平面図、図5(a)~(h)は該大判基板の裏面図、図6(a)~(h)は図4(a)~(h)の長手方向中央部に沿った1チップ相当分の断面図をそれぞれ示している。
Next, the manufacturing process of the sulfurization detection resistor 100 will be described with reference to FIGS. 4 to 6. 4 (a) to 4 (h) are plan views of the large format substrate used in this manufacturing process, FIGS. 5 (a) to 5 (h) are back views of the large format substrate, and FIGS. 6 (a) to 6 (h) are shown. 4 (a) to 4 (h) show cross-sectional views corresponding to one chip along the central portion in the longitudinal direction.
まず、絶縁基板1が多数個取りされる大判基板を準備する。この大判基板には予め1次分割溝と2次分割溝が格子状に設けられており、両分割溝によって区切られたマス目の1つ1つが1個分のチップ領域となる。図4~図6には1個分のチップ領域に相当する大判基板が代表して示されているが、実際は多数個分のチップ領域に相当する大判基板に対して以下に説明する各工程が一括して行われる。
First, prepare a large-format board on which a large number of insulating boards 1 are taken. The large-format substrate is provided with a primary dividing groove and a secondary dividing groove in a grid pattern in advance, and each of the squares divided by both dividing grooves serves as a chip area for one piece. Although the large-format substrate corresponding to one chip region is represented in FIGS. 4 to 6, each step described below is actually performed for the large-format substrate corresponding to a large number of chip regions. It is done all at once.
すなわち、図4(a)と図5(a)および図6(a)に示すように、この大判基板10Aの裏面にAg系ペースト(Ag-Pd20%)をスクリーン印刷した後、これを乾燥・焼成して一対の第1裏電極4aを形成する。
That is, as shown in FIGS. 4 (a), 5 (a) and 6 (a), an Ag-based paste (Ag-Pd 20%) was screen-printed on the back surface of the large-format substrate 10A, and then dried. It is fired to form a pair of first back electrodes 4a.
次に、図4(b)と図5(b)および図6(b)に示すように、大判基板10Aの表面に銀を主成分とするAgペーストをスクリーン印刷して乾燥・焼成することにより、大判基板10Aの表面に長方形状の硫化検出導体2を形成する。なお、硫化検出導体2の長手方向両端部は大判基板10Aの短辺に達する位置まで延びているが、硫化検出導体2の短手方向の寸法は大判基板10Aの短辺長さに比べて若干短めに設定されている。
Next, as shown in FIGS. 4 (b), 5 (b) and 6 (b), an Ag paste containing silver as a main component is screen-printed on the surface of the large-format substrate 10A, dried and baked. , A rectangular sulfide detection conductor 2 is formed on the surface of the large-format substrate 10A. Both ends of the sulfide detection conductor 2 in the longitudinal direction extend to a position reaching the short side of the large format substrate 10A, but the dimension of the sulfide detection conductor 2 in the lateral direction is slightly larger than the short side length of the large format substrate 10A. It is set short.
次に、大判基板10Aの裏面に酸化ルテニウム等の抵抗体ペーストをスクリーン印刷して乾燥・焼成することにより、図4(c)と図5(c)および図6(c)に示すように、両端部が第1裏電極4aに重なる抵抗体5を形成する。
Next, a resistor paste such as ruthenium oxide was screen-printed on the back surface of the large-format substrate 10A, dried and fired, as shown in FIGS. 4 (c), 5 (c) and 6 (c). A resistor 5 having both ends overlapping the first back electrode 4a is formed.
次に、抵抗体5を覆う領域にガラスペーストをスクリーン印刷した後、このガラスペーストを乾燥・焼成してアンダーコート層6aを形成し、必要に応じてアンダーコート層6aの上から抵抗体5に図示せぬトリミング溝を形成して抵抗値調整する。しかる後、アンダーコート層6aの上からエポキシ系樹脂ペーストをスクリーン印刷し、これを加熱硬化してオーバーコート層6bを形成することにより、図4(d)と図5(d)および図6(d)に示すように、抵抗体5の全体を覆う2層構造の第2保護膜6を形成する。
Next, after screen-printing a glass paste on the area covering the resistor 5, the glass paste is dried and fired to form an undercoat layer 6a, and if necessary, the resistor 5 is formed from above the undercoat layer 6a. A trimming groove (not shown) is formed to adjust the resistance value. After that, the epoxy resin paste is screen-printed on the undercoat layer 6a and heat-cured to form the overcoat layer 6b, whereby FIGS. 4 (d), 5 (d) and 6 (D) and FIG. As shown in d), a second protective film 6 having a two-layer structure covering the entire resistor 5 is formed.
次に、第1裏電極4aに重なるように銀を主成分とするAg系ペーストをスクリーン印刷した後、これを加熱硬化して一対の第2裏電極4bを形成することにより、図4(e)と図5(e)および図6(e)に示すように、トータル膜厚の厚い2層構造の裏電極4を形成する。
Next, after screen-printing an Ag-based paste containing silver as a main component so as to overlap the first back electrode 4a, this is heat-cured to form a pair of second back electrodes 4b, whereby FIG. 4 (e). ), And as shown in FIGS. 5 (e) and 6 (e), a back electrode 4 having a two-layer structure with a large total film thickness is formed.
次に、硫化検出導体2の中央部にシリコン樹脂やフッ素樹脂等の樹脂ペースト等をスクリーン印刷し、これを加熱硬化することにより、図3(f)と図4(f)に示すように、硫化検出導体2の中央部を覆う硫化ガス透過性の第1保護膜3を形成する。
Next, a resin paste such as a silicone resin or a fluororesin is screen-printed on the central portion of the sulfide detection conductor 2, and this is heat-cured to form as shown in FIGS. 3 (f) and 4 (f). A sulfide gas permeable first protective film 3 that covers the central portion of the sulfide detection conductor 2 is formed.
次に、大判基板10Aを一次分割溝に沿って短冊状基板10Bに1次分割した後、短冊状基板10Bの分割面にNi/Crをスパッタすることにより、図4(g)と図5(g)および図6(g)に示すように、硫化検出導体2と裏電極4(第1裏電極4aと第2裏電極4b)間を接続する一対の端面電極7を形成する。なお、短冊状基板10Bの分割面にNi/Crをスパッタする代わりに、Ag系ペーストを塗布して加熱硬化させることにより端面電極7を形成するようにしても良い。
Next, the large-format substrate 10A is first divided into strip-shaped substrates 10B along the primary dividing groove, and then Ni / Cr is sputtered on the divided surfaces of the strip-shaped substrate 10B to show FIGS. 4 (g) and 5 (g). As shown in g) and FIG. 6 (g), a pair of end face electrodes 7 connecting the sulfurization detection conductor 2 and the back electrode 4 (the first back electrode 4a and the second back electrode 4b) are formed. Instead of sputtering Ni / Cr on the divided surface of the strip-shaped substrate 10B, the end face electrode 7 may be formed by applying an Ag-based paste and heat-curing it.
次に、短冊状基板10Bを二次分割溝に沿って複数のチップ状基板10Cに2次分割し、これらチップ状基板10Cに対して電解メッキを施してNiメッキ層とSnメッキ層を順次形成することにより、図4(h)と図5(h)および図6(h)に示すように、第1保護膜3から露出する硫化検出導体2の両端部と端面電極7および裏電極4の表面を覆う一対の外部電極8を形成する。これにより、硫化検出導体2の中央部を除く両端部が硫化ガス非透過性の外部電極8によって被覆され、第1保護膜3で覆われた領域を除く硫化検出導体2の中央部が硫化ガスと接触可能な硫化検出部2aとなり、図1~図3に示す硫化検出抵抗器100が完成する。
Next, the strip-shaped substrate 10B is secondarily divided into a plurality of chip-shaped substrates 10C along the secondary dividing groove, and the chip-shaped substrates 10C are electrolytically plated to sequentially form a Ni plating layer and a Sn plating layer. By doing so, as shown in FIGS. 4 (h), 5 (h), and 6 (h), both ends of the sulfide detection conductor 2 exposed from the first protective film 3, the end face electrode 7, and the back electrode 4 A pair of external electrodes 8 are formed to cover the surface. As a result, both ends of the sulfurization detection conductor 2 except the central portion are covered with the sulfur gas impermeable external electrode 8, and the central portion of the sulfurization detection conductor 2 excluding the region covered with the first protective film 3 is sulfurized gas. The sulfurization detection resistor 100 shown in FIGS. 1 to 3 is completed with the sulfurization detection unit 2a that can come into contact with
図7に示すように、このように構成された硫化検出抵抗器100は、図示せぬ他の電子部品と共に回路基板11上に実装された後、該回路基板11を硫化ガスを含む雰囲気に曝すことで使用される。その際、硫化検出抵抗器100は、硫化検出導体2が形成された絶縁基板1の表面側を上向きにした姿勢(すなわち、抵抗体5を下向きにした姿勢)で回路基板11上に搭載されるが、第2保護膜6のオーバーコート層6bが裏電極4を覆う一対の外部電極8の間に段落ち状に配置されているため、第2保護膜6と回路基板11との間に段差相当分の隙間が確保される。これにより、硫化検出抵抗器100を安定した姿勢で回路基板11上に搭載することができ、回路基板11の表面に設けられた配線パターン12と硫化検出抵抗器100の外部電極8とを容易に且つ確実に半田13で接合することができる。
As shown in FIG. 7, the sulfurization detection resistor 100 configured in this way is mounted on the circuit board 11 together with other electronic components (not shown), and then the circuit board 11 is exposed to an atmosphere containing sulfur gas. Used by At that time, the sulfide detection resistor 100 is mounted on the circuit board 11 in a posture in which the surface side of the insulating substrate 1 on which the sulfide detection conductor 2 is formed faces upward (that is, a posture in which the resistor 5 faces downward). However, since the overcoat layer 6b of the second protective film 6 is arranged in a stepped manner between the pair of external electrodes 8 covering the back electrode 4, there is a step between the second protective film 6 and the circuit board 11. A considerable amount of gap is secured. As a result, the sulfurization detection resistor 100 can be mounted on the circuit board 11 in a stable posture, and the wiring pattern 12 provided on the surface of the circuit board 11 and the external electrode 8 of the sulfurization detection resistor 100 can be easily mounted. Moreover, it can be reliably joined with the solder 13.
このようにして回路基板11に実装された硫化検出抵抗器100が硫化ガスに曝されると、硫化ガスが第1保護膜3を透過して硫化検出導体2の硫化検出部2aに接触するため、経年的に累積硫化量が増えていくことにより、硫化検出部2aが第1保護膜3の内部で断線し、この時点で抵抗体5を流れる電流の抵抗値によって硫化の度合いを正確に検出することができる。しかも、絶縁基板1の表面側に設けられた硫化検出導体2が断線した状態になっても、絶縁基板1の裏面側に設けられた抵抗体5は硫化されないため、一対の外部電極8間の導通を抵抗体5によって確保することができる。
When the sulfurization detection resistor 100 mounted on the circuit board 11 is exposed to the sulfurization gas in this way, the sulfurization gas permeates through the first protective film 3 and comes into contact with the sulfurization detection portion 2a of the sulfurization detection conductor 2. As the cumulative amount of sulfurization increases over time, the sulfurization detection unit 2a breaks inside the first protective film 3, and at this point, the degree of sulfurization is accurately detected by the resistance value of the current flowing through the resistor 5. can do. Moreover, even if the sulfide detection conductor 2 provided on the front surface side of the insulating substrate 1 is disconnected, the resistor 5 provided on the back surface side of the insulating substrate 1 is not sulfided, so that between the pair of external electrodes 8. Conduction can be ensured by the resistor 5.
以上説明したように、本実施形態例に係る硫化検出抵抗器100では、硫化検出部2aを有する硫化検出導体2と第2保護膜6で覆われた抵抗体5とが絶縁基板1の表裏両面に振り分けて設けられているため、絶縁基板1の表面側に設けられた硫化検出導体2の硫化検出部2aが累積的な硫化により断線したことを、絶縁基板1の裏面側に設けられた抵抗体5を流れる電流の抵抗値により正確に検出することができ、しかも、硫化検出導体2が断線した状態になっても外部電極8間の導通を確保することができる。
As described above, in the sulfide detection resistor 100 according to the present embodiment, the sulfide detection conductor 2 having the sulfide detection portion 2a and the resistor 5 covered with the second protective film 6 are both front and back surfaces of the insulating substrate 1. A resistor provided on the back surface side of the insulating substrate 1 that the sulfide detecting portion 2a of the sulfide detecting conductor 2 provided on the front surface side of the insulating substrate 1 was broken due to cumulative sulfide. It can be accurately detected by the resistance value of the current flowing through the body 5, and moreover, the conduction between the external electrodes 8 can be ensured even if the sulfide detection conductor 2 is disconnected.
また、本実施形態例に係る硫化検出抵抗器100では、絶縁基板1の裏面から第2保護膜6に至る高さ寸法が、絶縁基板1の裏面から裏電極4を覆う外部電極8に至る高さ寸法に比べて小さくなっており、裏電極4を覆う一対の外部電極8で挟まれた領域に第2保護膜6が段落ち状に配置された構成となっているため、硫化検出導体2が形成された絶縁基板1の表面側を上向きにした姿勢で回路基板11に実装した際に、絶縁基板1の裏面側に形成された第2保護膜6と回路基板11との間に両者の当接を回避する隙間が確保され、硫化検出抵抗器100を安定した姿勢で回路基板11上に実装することができる。しかも、裏電極4が、絶縁基板1の裏面上に形成された第1裏電極4aと、第1裏電極4a上に積層された第2裏電極4bとの積層構造(2層構造)からなるため、高さ寸法の厚い裏電極4を容易に形成することができる。
Further, in the sulfurization detection resistor 100 according to the present embodiment, the height dimension from the back surface of the insulating substrate 1 to the second protective film 6 is the height from the back surface of the insulating substrate 1 to the external electrode 8 covering the back electrode 4. The size is smaller than the size, and the second protective film 6 is arranged in a stepped-down shape in the region sandwiched between the pair of external electrodes 8 covering the back electrode 4, so that the sulfurization detection conductor 2 When mounted on the circuit board 11 in a posture in which the front surface side of the insulating substrate 1 formed with the above is facing upward, both are placed between the second protective film 6 formed on the back surface side of the insulating substrate 1 and the circuit board 11. A gap for avoiding contact is secured, and the sulfurization detection resistor 100 can be mounted on the circuit board 11 in a stable posture. Moreover, the back electrode 4 has a laminated structure (two-layer structure) of the first back electrode 4a formed on the back surface of the insulating substrate 1 and the second back electrode 4b laminated on the first back electrode 4a. Therefore, the back electrode 4 having a large height can be easily formed.
また、本実施形態例に係る硫化検出抵抗器100では、硫化検出導体2の硫化検出部2aが硫化ガス透過性の第1保護膜3によって覆われているため、硫化検出部2aが外部からの接触の影響を受け難くなると共に、硫化検出部2aを除く硫化検出導体2の両端部に外部電極8を容易にめっき形成することができる。ただし、第1保護膜3を省略して硫化検出部2aが外部に露出する構成にすることも可能であり、その場合は、硫化検出部2aを溶解剥離型のレジスト膜で被覆した状態で外部電極8をめっき形成し、外部電極8のめっき形成後にレジスト膜を溶剤で剥離・除去して硫化検出部2aを露出させれば良い。
Further, in the sulfurization detection resistor 100 according to the present embodiment, since the sulfurization detection unit 2a of the sulfurization detection conductor 2 is covered with the first protective film 3 that is permeable to sulfurization gas, the sulfurization detection unit 2a is from the outside. In addition to being less susceptible to contact, external electrodes 8 can be easily plated on both ends of the sulfurization detection conductor 2 excluding the sulfurization detection portion 2a. However, it is also possible to omit the first protective film 3 so that the sulfide detection part 2a is exposed to the outside. In that case, the sulfide detection part 2a is covered with a melt-release type resist film and is exposed to the outside. The electrode 8 may be plated, and after the external electrode 8 is plated, the resist film may be peeled off and removed with a solvent to expose the sulfide detection unit 2a.
1 絶縁基板
2 硫化検出導体
2a 硫化検出部
3 第1保護膜
4 裏電極4
4a 第1裏電極
4b 第2裏電極
5 抵抗体
6 第2保護膜
6a アンダーコート層
6b オーバーコート層
7 端面電極
8 外部電極
10A 大判基板
10B 短冊状基板
10c チップ状基板
11 回路基板
12 配線パターン
13 半田
100 硫化検出抵抗器
1Insulated substrate 2 Sulfurization detection conductor 2a Sulfurization detection unit 3 First protective film 4 Back electrode 4
4a 1st backelectrode 4b 2nd back electrode 5 Resistor 6 2nd protective film 6a Undercoat layer 6b Overcoat layer 7 End face electrode 8 External electrode 10A Large format board 10B Strip-shaped board 10c Chip-shaped board 11 Circuit board 12 Wiring pattern 13 Solder 100 Sulfurization detection resistor
2 硫化検出導体
2a 硫化検出部
3 第1保護膜
4 裏電極4
4a 第1裏電極
4b 第2裏電極
5 抵抗体
6 第2保護膜
6a アンダーコート層
6b オーバーコート層
7 端面電極
8 外部電極
10A 大判基板
10B 短冊状基板
10c チップ状基板
11 回路基板
12 配線パターン
13 半田
100 硫化検出抵抗器
1
4a 1st back
Claims (4)
- 直方体形状の絶縁基板と、前記絶縁基板の表面に設けられた硫化可能な硫化検出導体と、前記絶縁基板の裏面における長手方向両端部に設けられた一対の裏電極と、一対の前記裏電極間を接続する抵抗体と、前記抵抗体を覆う保護膜と、前記硫化検出導体の長手方向両端部と前記裏電極を導通する一対の端面電極と、前記端面電極と前記裏電極を覆う一対の外部電極と、を備え、
前記硫化検出導体の長手方向両端部が一対の前記外部電極によって覆われており、一対の前記外部電極で覆われていない領域の前記硫化検出導体が硫化ガスと接触可能な硫化検出部になっていることを特徴とする硫化検出抵抗器。 Between a rectangular body-shaped insulating substrate, a sulphurizable sulfide detection conductor provided on the surface of the insulating substrate, a pair of back electrodes provided at both ends in the longitudinal direction on the back surface of the insulating substrate, and a pair of back electrodes. A resistor that connects the resistors, a protective film that covers the resistor, a pair of end face electrodes that conduct longitudinal ends of the sulfurization detection conductor and the back electrode, and a pair of external electrodes that cover the end face electrode and the back electrode. With electrodes,
Both ends of the sulfurization detection conductor in the longitudinal direction are covered by the pair of external electrodes, and the sulfurization detection conductor in a region not covered by the pair of external electrodes serves as a sulfurization detection portion capable of contacting the sulfurization gas. A sulfurization detection resistor characterized by being present. - 請求項1に記載の硫化検出抵抗器において、
前記絶縁基板の裏面から前記保護膜までの高さ寸法が、前記絶縁基板の裏面から前記裏電極を覆う前記外部電極までの高さ寸法に比べて小さくなるように設定されていることを特徴とする硫化検出抵抗器。 In the sulfurization detection resistor according to claim 1.
The height dimension from the back surface of the insulating substrate to the protective film is set to be smaller than the height dimension from the back surface of the insulating substrate to the external electrode covering the back electrode. Sulfurization detection resistor. - 請求項2に記載の硫化検出抵抗器において、
前記裏電極が、前記絶縁基板の裏面上に形成された第1裏電極と、該第1裏電極上に積層された第2裏電極とを含んでいることを特徴とする硫化検出抵抗器。 In the sulfurization detection resistor according to claim 2.
A sulfurization detection resistor, characterized in that the back electrode includes a first back electrode formed on the back surface of the insulating substrate and a second back electrode laminated on the first back electrode. - 請求項1に記載の硫化検出抵抗器において、
前記硫化検出部が硫化ガス透過性保護膜によって覆われていることを特徴とする硫化検出抵抗器。 In the sulfurization detection resistor according to claim 1.
A sulfurization detection resistor characterized in that the sulfurization detection portion is covered with a sulfurization gas permeable protective film.
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JPH10300699A (en) * | 1997-04-25 | 1998-11-13 | Mitsubishi Electric Corp | Environment-diagnosing device for electrical equipment |
JP2001143902A (en) * | 1999-11-16 | 2001-05-25 | Matsushita Electric Ind Co Ltd | Resistor and its manufacturing method |
JP2009250611A (en) * | 2008-04-01 | 2009-10-29 | Taiyosha Electric Co Ltd | Sulfuration detecting sensor, sulfuration detection circuit, and manufacturing method of sulfuration detection sensor |
JP2016152258A (en) * | 2015-02-16 | 2016-08-22 | Koa株式会社 | Chip resistor for board inner layer and component built-in circuit board |
US20180174720A1 (en) * | 2016-12-15 | 2018-06-21 | National Cheng Kung University | Methods of Fabricating Chip Resistors Using Aluminum Terminal Electrodes |
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JPH10300699A (en) * | 1997-04-25 | 1998-11-13 | Mitsubishi Electric Corp | Environment-diagnosing device for electrical equipment |
JP2001143902A (en) * | 1999-11-16 | 2001-05-25 | Matsushita Electric Ind Co Ltd | Resistor and its manufacturing method |
JP2009250611A (en) * | 2008-04-01 | 2009-10-29 | Taiyosha Electric Co Ltd | Sulfuration detecting sensor, sulfuration detection circuit, and manufacturing method of sulfuration detection sensor |
JP2016152258A (en) * | 2015-02-16 | 2016-08-22 | Koa株式会社 | Chip resistor for board inner layer and component built-in circuit board |
US20180174720A1 (en) * | 2016-12-15 | 2018-06-21 | National Cheng Kung University | Methods of Fabricating Chip Resistors Using Aluminum Terminal Electrodes |
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