JP2011237220A - Gas detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas detector which can be made compact and is excellent in responsiveness when a detection starts and concentration of detection object gas changes.SOLUTION: A gas detector 1 comprises: a support 2; lead wires 51, 52, and 53; a sensor element 6; and an explosion proof member 7 with holes. The support 2 comprises: an insulating member; conductor wires formed on a surface of the insulating member; and an arrangement space 8 which is open to the outside. The lead wires 51, 52, and 53 are connected to the conductor wires and protrude from the support 2 to the arrangement space 8. The sensor element 6 is supported by the lead wires 51, 52, and 53 in the arrangement space 8 and is electrically connected to the lead wires 51, 52, and 53. The explosion proof member 7 covers the arrangement space 8.

Description

  The present invention relates to a gas detection device that detects a detection target gas in a gas.

  Conventionally, various structures have been proposed for a gas detection device using a sensor element that converts the concentration of a gas to be detected in a gas into an electrical signal. Among them, a coil-shaped heater or core wire electrode made of platinum or a platinum alloy is embedded in a gas-sensitive body mainly formed of a metal oxide semiconductor such as tin oxide in a spherical shape or an elliptical shape. The configured sensor element has high strength and durability, and is used in various gas detection devices 1. In such a gas detection device, the sensor element is exposed to a gas containing a detection target gas in a state heated by a heater, and a change in electrical resistance value due to adsorption of the detection target gas to the gas sensitive body is detected by the electrode. It detects using (refer patent document 1).

  FIG. 11 shows an example of the configuration of a conventional gas detection device 100. The sensor element 106 in the gas detection device 100 of the illustrated example includes a gas sensitive body constituted by a sintered body of a powder material containing a metal oxide semiconductor, and an electrode for measuring the electric resistance of the gas sensitive body. Consists of. The gas sensitive body is formed so as to cover the pair of electrodes. At this time, a coil-shaped heater combined electrode and a core wire electrode, which are electrodes, are used as a sensor base, and a gas sensitive body is formed in an elliptical shape so as to cover the heater combined electrode and the core wire electrode.

  The sensor element 106 is electrically connected to and supported by lead wires 151, 152, and 153 extending from both ends of the heater electrode and one end of the core wire electrode, respectively. The lead wires 151, 152, and 153 are connected and fixed to the three terminals 117, 117, and 117, respectively. The terminals 117, 117, and 117 pass through the resin base 118 that also serves as the bottom of the sensor housing 120, and one end thereof protrudes inside the sensor housing 120 and the other end protrudes outside the sensor housing 120. It is provided to do. The cap body 119 that constitutes the sensor housing 120 together with the base 118 is formed in a cylindrical shape having an opening at the top and bottom, and a stainless steel wire mesh 121 for exposure protection is provided at the upper opening. When the base 118 is attached to the lower opening of the cap body 119, the lower opening is closed by the base 118, thereby forming the sensor housing 120. The sensor element 106 is disposed inside the sensor casing 120.

JP 11-142356 A

  However, in the conventional gas detection device 1, the sensor element 106 is supported by the lead wires 151, 152, and 153 with respect to the terminals 117, 117, and 117 provided on the base 118 as described above. There is a problem that it becomes bulky, and the sensor element 106 having the wire mesh 121 for exposure protection is covered with the sensor element 106, so that the sensor element 106 is further bulky. For this reason, it is difficult to provide the gas detection device 100 for a small device.

  In this gas detection device 100, the concentration of the detection target gas in the gas introduced into the sensor housing 120 through the wire mesh 121 is detected. The sensor housing 120 includes the sensor element 106 and the lead wire 151. , 152, 153 and terminals 117, 117, 117 are required to have a certain amount of capacity. For this reason, after introducing gas into the sensor casing 120, the concentration of the detection target gas in the sensor casing 120 is It takes a certain amount of time to stabilize. For this reason, a certain amount of time is required from when the supply of gas to the sensor housing 120 is started until the concentration of the detection target gas can be accurately detected. In addition, when supplying gas to the sensor housing 120, it takes a certain amount of time until the gas in the sensor housing 120 is updated, so when the concentration of the detection target gas in the gas varies with time, It was difficult to quickly and accurately detect the change in concentration.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a gas detection device that can be downsized and has excellent responsiveness at the start of detection and when the concentration of a detection target gas changes. .

  The gas detection apparatus according to the present invention includes a support, a lead wire, a sensor element, and a perforated exposure prevention member. The support has an insulating member and a conductor wiring formed on the surface of the member, and an arrangement space that opens to the outside is formed. The lead wire is connected to the conductor wiring and protrudes from the support to the arrangement space. The sensor element is supported by the lead wire in the arrangement space and electrically connected to the lead wire. The exposure protection member covers the arrangement space.

  In the present invention, the support body includes a support substrate and a base body in which a recess is formed, the support substrate is formed on an insulating substrate and a surface of the insulating substrate, and the conductor wiring A first conductor wiring constituting at least a part of the support substrate, wherein the support substrate is disposed in the recess, the placement space is a space not occupied by the support substrate in the recess, and the lead wire is The exposure conductor may be connected to the first conductor wiring and cover the recess.

  In the present invention, the base body has a second conductor wiring constituting a part of the conductor wiring, the second conductor wiring is connected to the first conductor wiring in the recess, The second conductor wiring may be exposed to the outside on the outer surface of the base body.

  In the present invention, the arrangement space opens on the first surface of the support and the second surface opposite to the first surface, and the exposure prevention member covers the opening of the arrangement space. May be.

  In the present invention, the anti-exposure member is a sheet-like member formed in two, and the anti-exposure member may cover the opening of the arrangement space by sandwiching the support.

  In the present invention, the support includes a support substrate having a wiring constituting at least a part of the conductor wiring, and a spacer overlaid on a surface of the support substrate on which the wiring is formed, The arrangement space may be opened on the surface of the spacer opposite to the support substrate and the surface of the support substrate opposite to the spacer.

  According to the present invention, the gas detection device is downsized, and the inflow and outflow of gas in the arrangement space are promoted, so that the responsiveness at the start of detection of the detection target gas and when the concentration of the detection target gas changes is improved.

The first embodiment of the present invention is shown, (a) is a plan view, (b) is a front view. The (a) exploded perspective view which shows said 1st embodiment, (b) is a perspective view. The support substrate in said 1st embodiment is shown, (a) is a top view, (b) is a front view, (c) is a bottom view. The bottom plate in said 1st embodiment is shown, (a) is a top view, (b) is a front view, (c) is a bottom view. The frame in said 1st embodiment is shown, (a) is a top view, (b) is a front view. It is sectional drawing which shows a sensor element and a lead wire. The second embodiment of the present invention is shown, (a) is a front view and (b) is a side view. (A) is a top view which shows the support substrate in said 2nd embodiment, (b) is a top view which shows the support body in said 2nd embodiment. It is a graph which shows the test result of the responsiveness with respect to hydrogen of the gas detection apparatus about Example 1 and Comparative Example 1. It is a graph which shows the test result of the responsiveness with respect to hydrogen of the gas detection apparatus about Example 2 and Comparative Example 1. It is the partially broken front view which shows an example of a prior art.

[First embodiment]
1 and 2 show a gas detection device 1 according to the first embodiment. The gas detection device 1 includes a support 2, lead wires 51, 52, 53, a sensor element 6, and an exposure prevention member 7.

  The support body 2 has conductor wiring, and an arrangement space 8 that opens to the outside is formed. The support body 2 includes a support substrate 21 and a base body 31.

  As shown in FIG. 3, the support substrate 21 includes an insulating substrate 22 and a first conductor wiring formed on the surface of the insulating substrate 22. The insulating substrate 22 is formed of a resin substrate such as a glass base epoxy resin laminate, a ceramic substrate, or the like.

  The first conductor wiring is a wiring constituting a part of the conductor wiring of the support 2. When the insulating substrate 22 is formed from a resin substrate, for example, a copper foil is laminated on the insulating substrate 22 to produce a copper-clad laminate, and then the copper foil is subjected to pattern etching. By applying metal plating such as copper plating on the remaining copper foil, the first conductor wiring is formed. When the insulating substrate 22 is a ceramic substrate, the first conductor wiring is formed by an appropriate metallization method such as a plating method or a vapor deposition method.

  The size and shape of the support substrate 21 in plan view are, for example, a rectangular shape with a side of 3 to 6 mm, and the thickness of the support substrate 21 is, for example, 0.2 to 1 mm.

  A gap 23 is formed in the insulating substrate 22. The gap 23 includes a first surface (upper surface) facing the thickness direction of the insulating substrate 22, a second surface (lower surface) opposite to the first surface, and the first surface and the second surface. A third surface (one end surface) that faces in a direction parallel to the surface of the film is opened. The insulating substrate 22 has two supporting protrusions 24 and 25 at positions where the gap 23 is interposed. The protrusion dimensions of the support protrusions 24 and 25 are, for example, 1.3 to 2.5 mm. The width dimension of the gap 23 is, for example, 1.0 to 1.3 mm.

  The first conductor wiring includes three mutually independent wirings 41, 42, and 43. Each wiring 41, 42, 43 passes from the first surface of the insulating substrate 22 through the fourth surface (the other end surface) opposite to the third surface of the insulating substrate 22. Formed on the second surface. Three end face through holes 26, 26, 26 are formed on the fourth surface of the insulating substrate 22. On the fourth surface, the wires 41, 42, 43 are formed on the inner surfaces of the end surface through holes 26, 26, 26. The end face through hole means an element having a shape formed by half-cutting a normal through hole.

  On the first surface of the support substrate 21, the wires 41, 42, 43 are formed in a direction from the third surface to the fourth surface, and the three wires 41, 42, 43 are arranged in parallel and parallel. It is out. Of the three wirings 41, 42, 43, two wirings 41, 42 are formed from the support protrusions 24, 25 of the support substrate 21 toward the fourth surface. The remaining one wiring 43 is formed between the two wirings 41 and 42 from the position facing the gap 23 of the support substrate 21 toward the fourth surface.

  The base body 31 is an insulating member having a rectangular shape in plan view, and is made of, for example, ceramics. The size and shape of the base body 31 in plan view are, for example, a rectangular shape having a side of 3.5 to 10 mm, and the thickness is in the range of 0.2 to 1 mm, for example. A recess 32 is formed in the first surface (upper surface) facing the thickness direction of the base body 31. The shape of the recess 32 in plan view matches the shape of the support substrate 21 when the gap 23 is included, and the depth of the recess 32 is slightly larger than the thickness of the support substrate 21. Thereby, the support substrate 21 can be accommodated in the recess 32. The size and shape of the recess 32 in plan view are, for example, a rectangular shape with a side of 3 to 6 mm, and the depth of the recess 32 is a value larger than the thickness of the support substrate 21 in a range of 0.2 to 1 mm, for example.

  The base body 31 includes a bottom plate 33 and a frame body 34. As shown in FIG. 4, the bottom plate 33 is a flat plate member, and the frame body 34 is a rectangular frame member. The base body 31 is configured by joining the frame body 34 to the first surface (upper surface) facing the thickness direction of the bottom plate 33. A space surrounded by the frame 34 on the first surface side with respect to the bottom plate 33 is a recess 32.

  The base body 31 includes a second conductor wiring that constitutes a part of the conductor wiring of the support body 2. That is, the second conductor wiring constitutes the conductor wiring of the support 2 together with the first conductor wiring. The second conductor wiring is composed of wiring that the bottom plate 33 has and wiring that the frame body 34 has. These wirings are formed by, for example, a gold plating process.

  The bottom plate 33 is provided with three mutually independent wirings 44, 44, 44. On the first surface of the bottom plate 33, each wiring 44, 44, 44 is opposite to the third surface from a third surface (one end surface) facing in a direction parallel to the first surface of the bottom plate 33. It is formed in a direction toward the fourth surface (the other end surface) on the side, and three wirings 44, 44, 44 are arranged in parallel and parallel. Each wiring 44, 44, 44 is formed from the first surface of the bottom plate 33 through the fourth surface to the second surface (lower surface) opposite to the first surface of the bottom plate 33. ing. Three end face through-holes 35, 35, 35 are formed on the fourth surface of the bottom plate 33, and on the fourth surface, the wirings 44, 44, 44 are connected to the end face through-holes 35, 35, 35, respectively. It is formed on the inner surface.

  As shown in FIG. 5, an opening 36 is formed in the frame body 34. The opening 36 opens at a first surface (upper surface) facing the thickness direction of the frame body 34 and a second surface (lower surface) opposite to the first surface. Three end face through holes 37, 37, 37 are formed on the fourth surface (outer end face) facing the direction parallel to the first surface on the outer face of the frame body 34. Wirings 45, 45, 45 are formed on the inner surfaces of the end surface through holes 37, 37, 37. Three end surface through-holes 38, 38, 38 are also formed on the fifth surface (inner end surface) opposite to the fourth surface on the surface facing the opening 36 of the frame 34. Wirings 46, 46, 46 are also formed on the inner surfaces of the end surface through holes 38, 38, 38, respectively.

  The three wirings 46, 46, 46 on the fifth surface of the frame 34 are in contact with the three wirings 44, 44, 44 on the first surface of the bottom plate 33 and are electrically connected. The end surface through-holes 37, 37, 37 on the fourth surface of the frame 34 are overlapped on the end surface through-holes 35, 35, 35 on the fourth surface of the bottom plate 33, and two end surface throughs arranged vertically. The holes 35 and 37 are integrated to form one end face through hole. Accordingly, the three wires 45, 45, 45 on the fourth surface of the frame body 34 are also electrically connected to the three wires 44, 44, 44 of the bottom plate 33, respectively.

  As shown in FIGS. 1 and 2, the support substrate 21 is accommodated in the recess 32 of the base body 31. In this state, the three end surface through holes 26, 26, 26 of the support substrate 21 are opposed to the three end surface through holes 38, 38, 38 on the fifth surface of the frame 34. Two end face through holes 26 and 38 facing each other constitute one through hole. Thereby, the first conductor wiring of the support substrate 21 is electrically connected to the second conductor wiring of the base body 31. Further, the second surface of the support substrate 21 and the bottom surface of the recess 32 (the first surface of the bottom plate 33) overlap each other, so that the three wirings 41, 42, 43 of the support substrate 21 and the base body 31 The three wirings 44, 44, 44 are in contact with each other and are electrically connected to each other. Also by this, the first conductor wiring of the support substrate 21 is electrically connected to the second conductor wiring of the base body 31.

  The support substrate 21 may be accommodated in the recess 32 without being fixed, and the support substrate 21 is formed in the recess 32 by bonding or soldering using an appropriate adhesive such as an epoxy resin adhesive. It may be fixed to the inner surface.

  A space that is not occupied by the support substrate 21 in the recess 32 is the arrangement space 8. Most of the arrangement space 8 is occupied by the space on the first surface side in the gap 23 of the support substrate 21 and the support substrate 21. The arrangement space 8 is open at the first surface facing the thickness direction of the support 2.

  As long as the sensor element 6 has a function of converting the concentration of the detection target gas in the gas into an electric signal when exposed to the gas, a contact combustion type sensor element or a metal oxide semiconductor sensor is used. An element having any configuration such as an element may be used. The sensor element 6 in the present embodiment is a metal oxide semiconductor type composed of a gas sensitive body 61 containing a metal oxide semiconductor such as tin oxide and a detection electrode embedded in the gas sensitive body 61. This is a gas sensor element 6. The gas sensitive body 61 is formed by molding and baking a material containing a metal oxide semiconductor powder. The gas sensitive body 61 is formed in, for example, a spherical shape, an ellipsoidal shape, etc., for example, a spherical body having a longitudinal dimension of 0.2 to 0.6 mm and a lateral dimension perpendicular to the longitudinal direction of 0.2 to 0.6 mm. Or an ellipsoid. As shown in FIG. 6, a coil-shaped heater combined electrode 62 and a core wire electrode 63 are embedded in the gas sensitive body 61 as detection electrodes. The core wire electrode 63 is provided so as to penetrate the inside of the coil-shaped heater / electrode 62. This detection electrode is made of, for example, platinum or a platinum alloy.

  The lead wires 51, 52, 53 are electrically connected to the conductor wiring of the support 2 and protrude from the support 2 into the arrangement space 8. The lead wires 51, 52, 53 support the sensor element 6 in the arrangement space 8. The lead wires 51, 52, 53 are electrically connected to the sensor element 6. The lead wires 51, 52, 53 are made of, for example, platinum or a platinum alloy.

  In the present embodiment, the gas detection device includes three lead wires 51, 52, and 53. These lead wires 51 and 52 protrude outward from the gas sensitive body 61 from both ends of the heater electrode 62. That is, the lead wires 51 and 52 and the heater combined electrode 62 are formed by molding a single wire, and the heater combined electrode 62 is formed between the lead wires 51 and 52. The remaining lead wire 53 protrudes outward from the gas sensitive body 61 from the end of the core wire electrode 63. That is, the lead wire 53 and the core wire electrode 63 are composed of a single wire, and one end of the wire rod is a core wire electrode 63, and a portion other than the core wire electrode 63 is a lead wire 53.

  The lead wires 51, 52 and 53, and the heater combined electrode 62 and the core wire electrode 63 preferably have a wire diameter in the range of 15 to 25 μm.

  As shown in FIG. 1, the end portions of the lead wires 51, 52, and 53 are connected and fixed to the wirings 41, 42, and 43, respectively, at the edge portions around the arrangement space 8 on the support substrate 21. The The lead wires 51 and 52 are connected and fixed to the wirings 41 and 42 on the support protrusions 24 and 25 of the support substrate 21. The lead wire 53 is connected and fixed to the conductor wiring 43 at a position facing the gap 23 on the support substrate 21. For this reason, in the arrangement space 8, lead wires 51, 52, and 53 that support the sensor element 6 protrude from the three different directions around the sensor element 6 toward the sensor element 6. It is supported stably in the arrangement space 8.

  Although the sensor element 6 supported by the lead wires 51, 52, and 53 may protrude outside the gap 23 of the support substrate 21, the arrangement space 8 is expanded outside the gap 23 of the support substrate 21. It becomes easy to arrange the sensor element 6 in the arrangement space 8.

  In fixing the lead wires 51, 52, 53 to the wirings 41, 42, 43, for example, after nickel plating processing and gold plating processing are sequentially performed on the wirings 41, 42, 43 as necessary, for example, soldering, Lead wires 51, 52, 53 are formed on the wirings 41, 42, 43 by an appropriate method such as heat welding (or heat welding), ultrasonic welding (or ultrasonic welding), resistance welding (or resistance welding), or the like. Fixed. The lead wires 51, 52, 53 may be fixed before the support substrate 21 is accommodated in the recess 32 of the base body 31, and before the support substrate 21 is accommodated in the recess 32 of the base body 31. May be made. In particular, when the lead wires 51, 52, 53 are fixed to the wirings 41, 42, 43 before the support substrate 21 is accommodated in the recess 32 of the base body 31, the gap 23 becomes the first surface side of the support substrate 21. Since the lead wires 51, 52, 53 are fixed in a state of being widely opened to the second surface side and the third surface side, workability is improved.

  The exposure prevention member 7 is a perforated member that covers the arrangement space 8. In this embodiment, the exposure prevention member 7 is a plate-like member, and a plurality of through holes 71 are formed. The exposure prevention member 7 is made of, for example, ceramics. The planar view size of the exposure prevention member 7 is preferably the same as or smaller than the planar view size of the support 2, and needs to be larger than the planar view size of the recess 32. The thickness of the exposure member 7 is, for example, in the range of 0.2 to 1.0 mm.

  The exposure protection member 7 overlaps the support 2, so that the exposure protection member 7 covers the recess 32 of the support 2. The through hole 71 of the exposure prevention member 7 is formed at a position facing the outer edge portion of the gap 23 of the support substrate 21. The arrangement space 8 communicates with the outside of the gas detection device through the through hole 71.

  The exposure prevention member 7 is attached to the support body 2 by an appropriate technique such as bonding with an appropriate adhesive such as an epoxy resin adhesive or soldering.

  The size and shape of the gas detection device 1 in plan view are, for example, a rectangular shape with a side of 3.5 to 10 mm, for example, like the support 2, and the total thickness is in the range of 0.6 to 2.2 mm, for example.

  The gas detection device 1 configured as described above has a chip-like shape having a rectangular shape in plan view, and the sensor element 6 is accommodated in the arrangement space 8 inside the gas detection device 1. On the first surface (upper surface) facing the thickness direction of the gas detection device 1, a through hole 71 communicating with the arrangement space 8 is opened. On the second surface (lower surface) opposite to the first surface and the fourth surface (end surface) facing in the direction parallel to the first surface, the gas detection device 1 is electrically connected to the sensor element 6. Conductor wiring is exposed.

  The support 2 of the gas detection device 1 includes an insulating substrate 22 and a base 31 that are insulating members, and conductor wiring formed on the surfaces thereof. Sensor element 6 is connected via lead wires 51, 52, 53. Further, the sensor element 6 is supported in the arrangement space 8 by lead wires 51, 52 and 53, and the arrangement space 8 communicates with the outside through a through hole 71.

  Since the gas detection device 1 has the above configuration, the gas detection device 1 can be significantly reduced in size. In addition, since the perforated exposure prevention member 7 sufficiently ensures the circulation of gas inside and outside the arrangement space 8, the gas in the arrangement space 8 is quickly updated. For this reason, the inflow of the gas containing the detection target gas into the arrangement space 8 and the outflow of the gas containing the detection target gas from the arrangement space 8 are promoted, and therefore the responsiveness at the start of detection and when the concentration of the detection target gas changes. It will be excellent.

  The gas detection device 1 is used in a state where it is connected to a measurement circuit, for example. As the measurement circuit, a circuit for deriving the concentration of the detection target gas from the electrical signal generated from the sensor element 6 in the gas detection device 1 is used according to the configuration of the sensor element 6.

  When the metal oxide semiconductor type sensor element 6 as in the present embodiment is used, a voltage is applied to the heater combined electrode 62 through the conductor wirings 41 and 42 and the lead wires 51 and 52 as a measurement circuit. A circuit for deriving the concentration of the detection target gas based on the electric resistance value between the heater combined electrode 62 and the core wire electrode 63 is used. In this case, at the time of detection of the detection target gas, the heater circuit 62 is energized and heated by first applying a voltage to the heater electrode 62 through the conductor wiring and the lead wire. Thereby, the temperature of the gas sensitive body 61 is heated to a temperature suitable for detection of the detection target gas. When the gas detection device 1 is exposed to the gas containing the detection target gas in this state, the gas is introduced into the arrangement space 8 through the through-hole 71 of the exposure prevention member 7, and thereby the gas sensitive body 1 is converted into the gas. Be exposed. The electric resistance value of the gas sensitive body 61 varies according to the concentration of the detection target gas in the gas. Based on the electric resistance value of the gas sensitive body 61 between the heater serving electrode 62 and the core wire electrode 63, the measurement circuit derives the concentration of the detection target gas.

  When the gas detection device 1 is connected to the measurement circuit, the gas detection device 1 may be mounted on a mother board including the measurement circuit. In the present embodiment, since the conductor wiring is exposed to the outside on the second surface (lower surface) and the fourth surface (end surface) of the gas detection device, mounting on the mother board via this conductor wiring is easy. It is. For example, the gas detection device 1 is disposed on the mother substrate and the cream solder is solidified in a state where the cream solder is interposed between the terminal on the mother substrate and the conductor wiring on the second surface of the gas detection device. Thus, the gas detection device is mounted on the mother board. Alternatively, the gas detection device 1 is disposed on the mother substrate, and the terminals on the mother substrate and the conductor wiring on the fourth surface of the gas detection device are connected by solder or the like, so that the gas detection device is attached to the mother substrate. May be implemented. Both of these methods may be used in combination. In this way, the gas detection device 1 is handled as a chip component, and the gas detection device 1 can be easily mounted on the mother board by a method such as surface mounting. Therefore, the gas detection device 1 can be easily attached to various devices, and the device can be easily downsized.

  In the present embodiment, as described above, the conductor wiring is exposed to the outside on the second surface and the fourth surface of the gas detection device, but only the second surface of the gas detection device or the first surface as necessary. The conductor wiring may be exposed to the outside only on the four surfaces. The conductor wiring may be exposed on a surface other than the second surface and the fourth surface of the gas detection device.

[Second Embodiment]
FIG. 7 shows a gas detection device 1 according to the second embodiment. The gas detection device 1 includes a support body 2 including a support substrate 21 and a spacer 9, a sensor element 6, lead wires 51, 52, and 53, and an exposure prevention member 7.

  A support substrate 21 shown in FIG. 2A includes an insulating substrate 22 and conductor wiring formed on the insulating substrate 22. The insulating substrate 22 is formed of a resin substrate such as a glass base epoxy resin laminate, a ceramic substrate, or the like. The conductor wiring is formed, for example, by the same technique as that of the first conductor wiring in the first embodiment.

  The size and shape of the support substrate 21 in plan view are, for example, a rectangular shape with a side of 3 to 6 mm, and the thickness of the support substrate 21 is within a range of 0.2 to 1 mm, for example.

  A gap 23 is formed in the insulating substrate 22. The gap 23 includes a first surface (upper surface) facing the thickness direction of the insulating substrate 22, a second surface (lower surface) opposite to the first surface, and the first surface and the second surface. The third surface (one end surface) facing in the direction parallel to the surface of the surface is opened. The insulating substrate 22 has two supporting protrusions 24 and 25 at positions where the gap 23 is interposed. The protrusion dimensions of the support protrusions 24 and 25 are, for example, 1.3 to 2.5 mm. The width dimension of the gap 23 is, for example, 1.0 to 1.3 mm.

  The conductor wiring includes three mutually independent wirings 41, 42, and 43. Each wiring 41, 42, 43 is formed on the first surface of the insulating substrate 22. On this first surface, each wiring 41, 42, 43 is formed in a direction from the third surface of the insulating substrate 22 toward the fourth surface (the other end surface) opposite to the third surface. The three wirings 41, 42 and 43 are arranged in parallel and in parallel. Of the three wirings 41, 42, 43, two wirings 41, 42 are formed from the support protrusions 24, 25 of the support substrate 21 toward the fourth surface. The remaining one wiring 43 is formed between the two wirings 41 and 42 from the position facing the gap 23 of the support substrate 21 toward the fourth surface.

  The spacer 9 is an insulating plate-like member and is formed of, for example, a glass base material epoxy resin laminate. The spacer 9 is formed with an opening 91 that opens at a first surface (upper surface) facing in the thickness direction and a second surface (lower surface) opposite to the first surface. . The spacer 9 has a thickness of 0.2 to 0.8 mm, for example. The opening 91 of the spacer 9 is formed in a rectangular shape with one side of 2.5 to 4.5 mm, for example. As shown in FIG. 8B, the spacer 9 is overlaid on the first surface on the support substrate 21 at a position closer to the third surface side, and is fixed to the support substrate 21 with an adhesive or the like. Yes. The opening 91 of the spacer 9 communicates with the gap 23 of the support substrate 21, and the inside of the opening 91 and the gap 23 becomes the arrangement space 8. The arrangement space 8 is opened by a first surface (upper surface) facing the thickness direction of the support 2 and a second surface (lower surface) opposite to the first surface. In the arrangement space 8, the edge portion around the gap 23 on the first surface of the support substrate 21 is exposed, and the end portions of the three wirings 41, 42, and 43 are located in the arrangement space 8 at this edge portion. Exposed.

  The thickness of the support 2 that combines the support substrate 21 and the spacer 9 is, for example, 0.4 to 2 mm. Therefore, the thickness of the arrangement space 8 is also formed to be 0.4 to 2 mm.

  The configuration of the sensor element 6 and the lead wire is the same as in the case of the first embodiment. Each end of the lead wires 51, 52, 53 is connected and fixed to each end of the three wires 41, 42, 43 exposed in the arrangement space 8 in the support substrate 21 as shown in FIG. The Of these, the two lead wires 51, 52 are connected and fixed to the ends of the conductor wirings 41, 42 on the first surface (upper surface) of the support protrusions 24, 25 of the support substrate 21. The remaining lead wires 53 are connected and fixed to the edge facing the gap 23 between the two support protrusions 24 and 25 of the support substrate 21. Therefore, in the arrangement space 8, the lead wires 51, 52, 53 that support the sensor element 6 protrude from the three different directions around the sensor element 6 toward the sensor element 6. It is stably arranged in the arrangement space 8.

  A part of the sensor element 6 supported by the lead wires 51, 52, 53 may protrude outward from the gap 23 of the support substrate 21, but the arrangement space 8 is an opening of the spacer 9 from the gap 23. Therefore, the sensor element 6 easily fits in the arrangement space 8.

  In fixing the lead wires 51, 52, 53 to the wirings 41, 42, 43, for example, after the nickel plating process and the gold plating process are sequentially performed on the wirings 41, 42, 43 as necessary, for example, soldering is performed. , Lead wires 51, 52, 53 on the wirings 41, 42, 43 by an appropriate method such as heat welding (or heat welding), ultrasonic welding (or ultrasonic welding), resistance welding (or resistance welding). Is fixed. The lead wires 51, 52, and 53 may be fixed to the wirings 41, 42, and 43 before the spacer 9 is provided on the support substrate 21 or after the spacer 9 is provided on the support substrate 21. Also good. In particular, when the lead wires 51, 52, 53 are fixed to the wirings 41, 42, 43 before the spacer 9 is attached to the support substrate 21, the gap 23 becomes the first surface side of the support substrate 21, the second Since the lead wires 51, 52, 53 are fixed in a state of being widely opened to the surface side and the third surface side, workability is improved.

  The exposure prevention member 7 is a perforated member that covers the arrangement space 8, and is a sheet-like member in the present embodiment. The exposure-proof member 7 is preferably formed of a mesh sheet made of metal such as stainless steel having high strength, good moldability, and excellent porosity. As shown in FIG. 7, the exposure-proof member 7 is formed in two, and the exposure-proof member 7 covers the arrangement space 8 by sandwiching the end portion on the third surface side of the support 2. On the first surface of the support 2, the exposure protection member 7 covers the opening of the opening 91 of the spacer 9 by being disposed on the first surface of the spacer 9, and on the second surface side of the support 2. The exposure prevention member 7 is disposed on the second surface of the support substrate 21 to cover the opening of the gap 23 of the support substrate 21. Further, the bent portion of the exposure prevention member 7 covers the third surface of the support 2, thereby covering the opening of the gap 23 on the third surface of the support substrate 21. Thereby, the arrangement space 8 is covered by the exposure prevention member 7 and the sensor element 6 is protected. The exposure prevention member 7 is attached to the support 2 by an appropriate method such as adhesion using an adhesive.

  In this embodiment, since the insulating spacer 9 is interposed between the wirings 41, 42, 43 on the support substrate 21 and the exposure member 7, the wiring 41, even if the exposure member 7 is made of metal. No short circuit occurs in 42 and 43.

  The total thickness of the gas detection device 1 including the support substrate 21, the spacer 9, and the exposure prevention member 7 is particularly preferably 1.5 mm or less.

  In the gas detection device 1 according to the present embodiment, the sensor element 6 is disposed in the arrangement space 8 formed in the support 2, and the sensor element 6 is a lead wire with respect to the conductor wiring exposed on the surface of the support 2. 51, 52, 53. With such a structure, the gas detector 1 can be significantly reduced in size. In addition, it is easy to make the arrangement space 8 small, and the porous exposure member 7 allows the gas inside and outside the arrangement space 8 to flow on both the first surface and the second surface of the support 2. Secured well. Thereby, the inflow of the gas containing the detection target gas into the arrangement space 8 and the outflow of the gas containing the detection target gas from the arrangement space 8 are promoted. For this reason, the response when the detection starts and when the concentration of the detection target gas changes Excellent in properties.

  When the gas detector 1 is used, the gas detector 1 may be connected to the measurement circuit as in the case of the first embodiment.

[Example 1]
As the gas detection device 1, one having the configuration shown in FIG. 1 was used.

  In obtaining the support substrate 21, two support protrusions 24 and 25 having a protrusion dimension of 1.6 mm are formed on a ceramic substrate having dimensions of 3.3 mm × 3.5 mm × 0.4 mmt and a width of 1.6 mm therebetween. The gap 23 was formed, and three end face through holes were also formed. The ceramic substrate was subjected to gold plating with a thickness of 1 μm to form wirings 41, 42, and 43.

  In the sensor element 6, the gas sensitive body 61 is in the shape of an ellipsoid having a major axis of 0.5 mm and a minor axis of 0.3 mm, and the lead wires 51, 52, 53, the heater combined electrode 62, and the core wire electrode 63 are linear A platinum wire having a diameter of 20 μm was used.

  When producing the sensor element 6, tin oxide powder and α-alumina powder were mixed, and a solvent was added thereto to obtain a paste-like mixture. This paste-like mixture was applied to the heater combined electrode 62 and the core wire electrode 63 and fired to obtain a sintered body. After applying a solvent dispersion of indium oxide to the surface of the sintered body, the gas-sensitive body 61 was produced by further firing the dispersion.

  In connecting the lead wires 51, 52, 53 to the wirings 41, 42, 43 of the support substrate 21, the lead wires 51, 52, 53 were connected to the ends of the wirings 41, 42, 43 by resistance welding.

  In manufacturing the base body 31, the frame body 34 is formed with ceramics in a size of 4.5 mm × 4.3 mm × 0.8 mm, and the size of the opening of the frame body 34 in a plan view is 3.3 mm × 3. The thickness was 5 mm, and six end face through holes 37, 37, 37, 38, 38, 38 were also formed. The frame 34 was subjected to gold plating with a thickness of 1 μm to form wirings 45 and 46. On the other hand, the bottom plate 33 was made of ceramic with a size of 4.5 mm × 4.3 mm × 0.2 mmt, and three end face through holes 35, 35, 35 were formed in the bottom plate 33. The bottom plate 33 was subjected to gold plating with a thickness of 1 μm to form wirings 44. The base body 31 was obtained by bonding the frame body 34 and the bottom plate 33 together. The support substrate 21 was accommodated in the recess 32 of the base body 31. Thus, the support 2 was obtained, and the sensor element 6 was arranged in the arrangement space 8 of the support 2.

  The exposure protection member 7 was formed with ceramics in a size of 4 mm × 4 mm × 0.2 mmt. The exposure member 7 was formed with four through holes 71 having a diameter of 0.5 mm. The exposure member 7 was connected to the support 2 with an epoxy resin adhesive, and the arrangement space 8 was covered with the exposure member 7. Thereby, the gas detection apparatus 1 was obtained.

[Example 2]
As the gas detection device 1, one having the configuration shown in FIG. 7 was used.

  In obtaining the support substrate 21, the FR-4 type glass substrate epoxy resin copper-clad laminate (copper foil thickness 18 μm) having dimensions of 6 mm × 6 mm × 0.4 mmt is cut to have a protruding dimension of 2.8 mm. Are formed, and a gap 23 having a width of 1.6 mm is formed therebetween. After this glass substrate epoxy resin copper clad laminate was subjected to pattern etching, the remaining copper foil was plated with copper having a thickness of 20 μm to form wirings 41, 42, and 43.

  In obtaining the spacer 9, an opening 91 having a size of 2 mm × 3.84 mm was formed in an FR-4 type glass substrate epoxy resin laminate having a size of 4.9 mm × 5.8 mm × 0.4 mmt. The spacer 9 was overlapped on the support substrate 21 and bonded thereto, whereby the support body 2 was produced.

  In the sensor element 6, the gas sensitive body 61 is in the shape of an ellipsoid having a major axis of 0.5 mm and a minor axis of 0.3 mm, and the lead wires 51, 52, 53, the heater combined electrode 62, and the core wire electrode 63 are linear A platinum wire having a diameter of 20 μm was used.

  When producing the sensor element 6, tin oxide powder and α-alumina powder were mixed, and a solvent was added thereto to obtain a paste-like mixture. This paste-like mixture was applied to the heater combined electrode 62 and the core wire electrode 63 and fired to obtain a sintered body. After applying a solvent dispersion of indium oxide to the surface of the sintered body, the gas-sensitive body 61 was produced by further firing the dispersion.

  In connecting the lead wires 51, 52, and 53 to the wirings 41, 42, and 43, the end portions of the wirings 41, 42, and 43 are sequentially subjected to nickel plating treatment with a thickness of 5 μm and gold plating treatment with a thickness of 0.3 μm, Lead wires 51, 52, 53 were connected to the ends of the wires 41, 42, 43 by resistance welding.

  As the exposure prevention member 7, a 0.2 mm thick mesh sheet made of SUS304 stainless steel wire is used, and the sheet is folded in two and adhered to the support 2 so that the end of the support 2 is sandwiched. 7 covered the arrangement space 8.

[Comparative Example 1]
As the gas detection device 1, a device (sensor product number SB-30, manufactured by FIS Co., Ltd.) in which the sensor element 6 is accommodated in the sensor housing 20 as shown in FIG. 5 was used. A sensor element 6 having the same configuration as in Example 1 was used.

[Evaluation test]
Each gas detection device 1 obtained in Examples 1 and 2 and Comparative Example 1 was connected to a measurement circuit, and this gas detection device was heated to 420 ° C. by energizing the heater electrode 62. 1 was placed in an air stream, hydrogen was subsequently mixed in the stream at a concentration of 100 ppm, and then mixing of hydrogen into the stream was stopped. The ratio of the electrical resistance value Rs between the heater combined electrode 62 and the core wire electrode 63 measured in this case to the electrical resistance value R ₀ between the heater combined electrode 62 and the core wire electrode 63 in the air stream. The change in (Rs / R ₀ ) is shown in the graphs of FIGS. The electrical resistance value R ₀ is an electrical resistance value between the heater combined electrode 62 and the core wire electrode 63 when 120 seconds have elapsed from the start of the test in the test.

According to the results shown in FIG. 9 and FIG. 10, the value of Rs / R ₀ changes when hydrogen is mixed in the airflow in any of Example 1, Example 2, and Comparative Example 1. However, when the mixing of hydrogen into the airflow was stopped, the value of Rs / _R0 returned to the original value more quickly in Example 1 and Example 2 than in Comparative Example 1.

  Thereby, it was confirmed in Example 1 and Example 2 that it was excellent in the responsiveness at the time of hydrogen gas detection.

DESCRIPTION OF SYMBOLS 1 Gas detection apparatus 2 Support body 21 Support substrate 22 Insulating substrate 31 Base body 41 Wiring 42 Wiring 43 Wiring 51 Lead wire 52 Lead wire 53 Lead wire 6 Sensor element 7 Exposure member 8 Arrangement space 9 Spacer

Claims (6)

A support, a lead wire, a sensor element, and a perforated exposure prevention member are provided.
The support has an insulating member and a conductor wiring formed on the surface of the member, and an arrangement space that opens to the outside is formed.
The lead wire is connected to the conductor wiring and protrudes from the support to the arrangement space,
The sensor element is supported by the lead wire in the arrangement space and electrically connected to the lead wire;
The gas detection apparatus in which the exposure member covers the arrangement space. The support includes a support substrate and a base formed with a recess,
The support substrate includes an insulating substrate and a first conductor wiring formed on the surface of the insulating substrate and constituting at least a part of the conductor wiring;
The support substrate is disposed in the recess, and the placement space is a space not occupied by the support substrate in the recess;
The lead wire is connected to the first conductor wiring;
The gas detection device according to claim 1, wherein the exposure prevention member covers the recess. The base body has a second conductor wiring constituting a part of the conductor wiring,
The second conductor wiring is connected to the first conductor wiring in the recess;
The gas detection device according to claim 2, wherein the second conductor wiring is exposed to the outside on an outer surface of the base body.   The said arrangement | positioning space opens in the 1st surface in the said support body, and the 2nd surface on the opposite side to this 1st surface, and the said exposure member covers the opening of the said arrangement | positioning space. The gas detection apparatus as described.   The gas detection device according to claim 4, wherein the exposure prevention member is a sheet-like member formed in a fold, and the exposure prevention member covers the opening of the arrangement space by sandwiching the support.   The support includes a support substrate having a wiring constituting at least a part of the conductor wiring, and a spacer superimposed on a surface of the support substrate on which the wiring is formed, and the arrangement space is the spacer The gas detection device according to claim 4, wherein the gas detection device is opened on a surface of the support substrate opposite to the support substrate and a surface of the support substrate opposite to the spacer.

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