JP2019203876A - Sensor element and gas sensor - Google Patents

Abstract

To provide a sensor element and a gas sensor that, when the sensor element has three electrode pads at least on one side, makes the element compact.SOLUTION: A plate-like sensor element 100 has, at least on one side, three electrode pads 301 to 303 per one side. At least on one side, a group of two pads 301 and 302 are arranged side by side in a width direction, and one single pad 303 is arranged on a leading end side or a rear end side of the group of pads. The single pad has a body part 303b that is wider than a gap between the group of pads and electrically connected to a connection terminal 16, and connection parts 301c to 303c that are connected to a conductor formed in a through hole that extends in a thickness direction inside the sensor element, the connection parts adjacent to a side face of the body part.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a sensor element and a gas sensor suitably used for detecting the gas concentration of a specific gas contained in combustion gas or exhaust gas of a combustor or an internal combustion engine, for example.

Conventionally, a gas sensor for detecting the concentration of a specific component (oxygen or the like) in exhaust gas of an internal combustion engine has been used. As this gas sensor, a configuration including a plate-like sensor element is known (Patent Document 1). And in order to take out the detection output from the detection cell which a sensor element has, and to control the pump current of a pump cell, the electrode which constitutes a cell is connected to the electrode pad of the element surface via the through-hole conductor in the element. Yes.
By the way, in the case of the full-range air-fuel ratio sensor element or NOx sensor element, it has two or more cells, and an electrode pad for energizing the heater is also added. For this reason, as shown in FIG. 7, three electrode pads 1100, 1110, and 1120 may be formed on one side of the front and back surfaces of the sensor element 1000 in some cases.

In this case, if the three electrode pads 1100, 1110, and 1120 are arranged in the width direction on one side 1000a of the sensor element 1000, the electrode pads cannot be sufficiently spaced apart from each other, and the connection terminals connected to the electrode pads There is a risk of short circuiting between them. Therefore, the two electrode pads 1100 and 1110 are arranged apart from each other in the width direction, and one electrode pad 1120 is disposed on the rear end side of the electrode pads 1100 and 1110.
Further, the through-hole conductor 1200 in the element 1000 is connected so as to overlap the connection portions 1100c, 1110c, and 1120c of the electrode pads 1100, 1110, and 1120.

Japanese Patent Laying-Open No. 2015-232551 (FIG. 2)

Incidentally, since the electrode pads 1100, 1120 are vertically arranged in the direction of the axis O of the sensor element 1000, the overall length Lx of the electrode pads 1100, 1110, 1120 is also increased, and the element cannot be shortened or made compact. There is.
Specifically, since the connection portion 1120c of the electrode pad 1120 is formed on the through-hole conductor 1200, a step is formed with the surface of the electrode pad 1120, and slides with respect to the electrode pad 1120 in the direction of the axis O as indicated by an arrow F. The connection terminal (not shown) to be reliably contacted with the connection portion 1120c is difficult, and the connection portion 1120c does not function effectively as an electrode. For this reason, useless space is generated in the direction of the axis O by the amount of the connecting portion 1120c. In this case, if the connecting portion 1120c at the tip of the electrode pad 1120 is advanced between the electrode pads 1100 and 1110 so as to overlap in the axial direction, the overall length Lx seems to be shortened.

  However, in this case, since the distance G between the through-hole conductor 1200 and the electrode pad 1100 (1110) is close, there is a possibility that both are short-circuited. That is, in general, the through-hole conductor 1200 is formed by evacuating and filling the through-hole with a conductive paste. At this time, the conductive paste is scattered around the through-hole, and therefore if the distance G is too short, the conductive paste Is short-circuited to the electrode pad 1100 (1110). Therefore, in order to secure the distance G, the tip of the electrode pad 1120 needs to be separated from the rear ends of the electrode pads 1100 and 1110 in the axial direction, and the length Lx cannot be shortened. The same applies to a via-hole conductor that fills a via hole instead of the through-hole conductor 1200. That is, when filling the via hole with the conductive paste, the conductive paste protrudes around the via hole, and if the distance G is too short, the conductive paste may short-circuit with the electrode pad 1100 (1110).

  In view of the above, an object of the present invention is to provide a sensor element and a gas sensor in which the element is shortened when the sensor element has three electrode pads on at least one surface.

  In order to solve the above problems, the sensor element according to the first aspect of the present invention is a plate-like sensor element extending in the axial direction, and has three electrode pads per one side on at least one side of its main surface. In the sensor element in which each electrode pad is electrically connected to the connection terminal, the pad group arranged in the width direction on at least one surface, and the width direction while being positioned on the front end side or the rear end side of the pad group A single pad that does not overlap with the pad group as seen in FIG. 3, and the single pad is a connection portion connected to a conductor formed in a through hole extending in the thickness direction inside the sensor element, And a connecting portion adjacent to a side surface of the main body portion.

  According to this sensor element, even if the electrode pads are arranged vertically in the direction of the axis O of the sensor element, the connection part connected to the conductor formed in the through hole of the sensor element is located on the side surface of the main body part. Since they are adjacent to each other, it is possible to prevent the connecting portion that does not function effectively as an electrode from protruding from the front of the main body portion and create a useless space in the axial direction, thereby making it possible to shorten or downsize the sensor element.

In the sensor element of the present invention, the connection portion may be located in the middle of the axial direction among the side surfaces of the main body portion.
Since the connection portion is connected to the conductor formed in the through hole of the sensor element, if the connection portion is located in the middle of the side surface of the main body portion in the axial direction, the connection portion may Compared to the case of being located on the end face, it is easy to connect to the conductor even if the connecting portion is slightly displaced.

In the sensor element of the present invention, when the width in the width direction of the connecting portion of the single pad is W and the width in the width direction of the single pad is Wp, Wp <3.1 × W Good.
According to this sensor element, by setting Wp <3.1 × W, Wp is relatively smaller than W, and the amount of Pt used for a single pad is reduced by that amount, thereby reducing the cost. Further reduction can be achieved.

In the sensor element of the present invention, when the length of the electrode pad of the pad group having the shorter length in the axial direction is L1, and the length of the single pad in the axial direction is L2, L1> L2 It may be.
According to this sensor element, by setting L1> L2, even if the electrode pads are arranged vertically in the direction of the axis O of the sensor element, the entire length of the electrode pads is shorter than when L1 = L2, and the sensor element Can be further reduced in size and size.

  A sensor element according to a second aspect of the present invention is a plate-like sensor element extending in the axial direction, and has three electrode pads per one side of at least one of its main surfaces, and each electrode pad. In the sensor element that is electrically connected to the connection terminal, the pad group arranged in the width direction on at least one surface, and the pad as viewed in the width direction while being positioned at the front end side or the rear end side of the pad group A single pad that does not overlap the group, and the single pad is connected to a conductor that is wider than the gap between the pad groups and is formed in a through hole extending in the thickness direction inside the sensor element. L1> L2, where L1 is the length of the electrode pad of the pad group having the shorter length in the axial direction, and L2 is the length of the single pad in the axial direction, and the through hole Of the single pad Characterized in that it does not overlap with the direction center.

According to this sensor element, even if the electrode pads are arranged vertically in the direction of the axis O of the sensor element, a portion of the single pad that is connected to the conductor formed in the through hole of the sensor element is included in the single pad. Therefore, it is possible to suppress the connection portion with the conductor that does not function effectively as an electrode from protruding beyond the tip of the single pad, thereby generating a useless space in the axial direction, and the sensor element can be shortened or made compact.
In addition, if the through hole does not overlap the center of the single pad in the width direction, the surface of the single pad near the center of the width direction will not have any connection part with the conductor, and all of the single pad will be in contact with the connection terminal without fail. L2 can be reduced by that amount.

  In the sensor element of the present invention, the through hole is a through hole, and a conductor may be formed in the through hole.

  In the sensor element of the present invention, the through hole is a via hole, and the via hole may be filled with a conductor.

  The gas sensor of the present invention comprises a sensor element and a metal shell that holds the sensor element, wherein the sensor element uses the sensor element according to any one of claims 1 to 7. To do.

  According to the present invention, when the sensor element has at least three electrode pads on one side, the element is shortened, and the reliability of the electrical connection between the electrode pad and the connection terminal is ensured. Can be suppressed.

It is sectional drawing which follows the axial direction of the gas sensor (oxygen sensor) provided with the sensor element which concerns on embodiment of the 1st viewpoint of this invention. It is sectional drawing which follows the axial direction of a sensor element. It is a model perspective view which shows the form by which a through-hole conductor is connected to an electrode pad. It is a top view which shows the electrode pad of both surfaces of the main surface of a sensor element. It is a top view which shows three electrode pads of the single side | surface of a sensor element. It is a top view which shows the form of the electrode pad in the sensor element which concerns on embodiment of the 2nd viewpoint of this invention. It is a fragmentary perspective view which shows three electrode pads of the single side | surface of the conventional sensor element.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a cross-sectional view along the longitudinal direction (axis O direction) of a gas sensor (NOx sensor) 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view along the axis O direction of the sensor element 100.

  As shown in FIG. 1, the gas sensor 1 includes a sensor element (NOx sensor element) 100, a metal shell 30 that holds the sensor element 100 and the like, a protector 24 that is attached to the tip of the metal shell 30, and the like. Yes. The sensor element 100 is disposed so as to extend in the direction of the axis O.

The metal shell 30 is made of SUS430, and has a male screw portion 31 for attaching the gas sensor to the exhaust pipe, and a hexagonal portion 32 to which an attachment tool is applied at the time of attachment. Further, the metal shell 30 is provided with a metal side step portion 33 protruding radially inward, and this metal side step portion 33 supports a metal holder 34 for holding the sensor element 100. .
Inside the metal holder 34, a ceramic holder 35 and a talc 36 are arranged in this order from the tip side. The talc 36 includes a first talc 37 disposed in the metal holder 34 and a second talc 38 disposed over the rear end of the metal holder 34.
The sensor element 100 is fixed to the metal holder 34 by compressing and filling the first talc 37 in the metal holder 34. In addition, the second talc 38 is compressed and filled in the metal shell 30, thereby ensuring a sealing property between the outer surface of the sensor element 100 and the inner surface of the metal shell 30.

  An alumina sleeve 39 is disposed on the rear end side of the second talc 38. The sleeve 39 is formed in a multi-stage cylindrical shape, is provided with a shaft hole 39a along the axis, and the sensor element 100 is inserted therein. The caulking portion 30 a on the rear end side of the metal shell 30 is bent inward, and the sleeve 39 is pressed to the front end side of the metal shell 30 through the stainless steel ring member 40.

  Further, a metal protector 24 having a plurality of gas intake holes 24a is attached to the outer periphery on the front end side of the metallic shell 30 by covering the distal end portion of the sensor element 100 protruding from the distal end of the metallic shell 30 by welding. . This protector 24 has a double structure, a cylindrical outer protector 41 having a uniform outer diameter on the outer side, and an outer diameter of the rear end part 42a on the inner side from the outer diameter of the front end part 42b. An inner protector 42 having a bottomed cylindrical shape that is formed to be larger is also arranged.

  On the other hand, on the rear end side of the metal shell 30, the front end side of the outer tube 25 made of SUS430 is inserted. The outer cylinder 25 has a distal end portion 25a whose diameter is enlarged on the distal end side fixed to the metal shell 30 by laser welding or the like. A separator 50 is disposed inside the rear end side of the outer cylinder 25, and a holding member 51 is interposed in a gap between the separator 50 and the outer cylinder 25. The holding member 51 is fixed by the outer cylinder 25 and the separator 50 by engaging a protrusion 50 a of the separator 50 described later and caulking the outer cylinder 25.

  Further, the separator 50 is provided with through holes 50b for inserting the six lead wires 11 of the sensor element 100 from the front end side to the rear end side (in FIG. 1, four lead wires 11 are provided). Only display). The connection hole 16 that connects the lead wire 11 and the electrode pads 301 to 306 (see FIG. 4) of the sensor element 100 is accommodated in the insertion hole 50 b. Each lead wire 11 is connected to a connector (not shown) outside. An electrical signal is input / output between the external device such as the ECU and each lead wire 11 through this connector. Although not shown in detail, each lead wire 11 has a structure in which the conductive wire is covered with an insulating film made of resin, and the leading end of the lead wire from which the insulating film is peeled is crimped to the rear end of the connection terminal 16. Has been.

  Further, a substantially cylindrical rubber cap 52 for closing the opening 25 b on the rear end side of the outer cylinder 25 is disposed on the rear end side of the separator 50. The rubber cap 52 is fixed to the outer cylinder 25 by caulking the outer periphery of the outer cylinder 25 toward the radially inner side in a state where the rubber cap 52 is mounted in the rear end of the outer cylinder 25. The rubber cap 52 is also provided with insertion holes 52a for inserting the lead wires 11 from the front end side to the rear end side.

  As shown in FIG. 2, the NOx sensor element 100 has an elongated and long plate shape, and three layers of plate-like solid electrolyte bodies 109, 105, 151 are interposed between them and an insulator 180 made of alumina or the like. , 185 are sandwiched between layers, and the laminated structure forms the detection element unit 300. Further, sheet-like insulating layers 103 and 101 mainly composed of alumina are laminated on the outer layer (the lower side in FIG. 2) on the solid electrolyte body 151 side, and a heat generating portion 102 composed of a heater pattern mainly composed of Pt therebetween. A heater unit 200 in which is embedded is provided.

The detection element unit 300 includes the following oxygen pump cell (Ip1 cell) 140, oxygen concentration detection cell (Vs cell) 130, and second pump cell (Ip2 cell) 150.
The oxygen pump cell 140 is formed of the second solid electrolyte body 109 and the third electrode 108 and the fourth electrode 110 formed on both surfaces thereof. The oxygen concentration detection cell 130 is formed of the first solid electrolyte body 105 and the first electrode 104 and the second electrode 106 formed on both surfaces thereof. A hollow measurement chamber 107 as a small space is formed between the solid electrolyte body 109 and the solid electrolyte body 105, and the second electrode 106 and the third electrode 108 are disposed in the measurement chamber 107. . The measurement chamber 107 communicates with the outside on the distal end side, and a diffusion rate controlling portion 115 is disposed at the communicating portion.

A protective layer 111 is formed on the surface of the second solid electrolyte body 109 so as to sandwich the fourth electrode 110. Further, a portion of the protective layer 111 that covers the fourth electrode 110 is cut out to embed a porous electrode protective portion 113.
The oxygen concentration detection cell 130 generates an electromotive force in accordance with an oxygen partial pressure difference between the measurement chamber 107 and a reference oxygen chamber 170 described later. The oxygen pump cell 140 pumps or pumps oxygen into the measurement chamber 107.

Further, on the rear end side of the sensor element 100 in the measurement chamber 107, a second diffusion resistance unit 117 that adjusts gas diffusion is provided as a partition between the second measurement chamber (NOx measurement chamber) 160 and the measurement chamber 107. ing. A second pump cell 150 is formed from the third solid electrolyte body 151, the fifth electrode 152, and the sixth electrode 153.
Here, the third solid electrolyte body 151 is disposed so as to face the solid electrolyte body 105 with the insulator 185 interposed therebetween. Further, the insulator 185 is not disposed at the position where the fifth electrode 152 is formed, and a reference oxygen chamber 170 is formed as an independent space. In the reference oxygen chamber 170, the first electrode 104 of the oxygen concentration detection cell 130 is also disposed. The reference oxygen chamber 170 is filled with a ceramic porous body.

Also, the insulator 185 is not disposed at the position where the sixth electrode 153 is formed, and the insulator 185 is separated from the reference oxygen chamber 170, and the hollow second measurement chamber 160 as an independent small space is provided. Is formed. The solid electrolyte body 105 and the insulator 180 are provided with openings 125 and 181 so as to communicate with the second measurement chamber 160. As described above, the measurement chamber 107 and the opening 181 are connected to each other. The second diffused resistor 117 is interposed between them.
The second pump cell 150 can pump oxygen between the reference oxygen chamber 170 and the second measurement chamber 160 separated by the insulator 185.

  On the other hand, the heater unit 200 includes a first base 101 and a second base 103 mainly composed of alumina, and a heating element 102 mainly composed of platinum sandwiched between the first base 101 and the second base 103. . The heating element 102 has a heating part located on the distal end side and a pair of heater lead parts extending from the heating part along the longitudinal direction of the first base (not shown). And the terminal of a heater lead part is electrically connected with electrode pad 304,305 (refer FIG. 4) via the through-hole conductor provided in a 1st base | substrate.

  In the NOx sensor element 100, pumping is performed by controlling the current flowing through the oxygen pump cell 140 so that the output voltage of the oxygen concentration detection cell 130 becomes a constant value. The exhaust gas whose oxygen concentration is adjusted in this way is introduced into the second measurement chamber 160 via the second diffusion resistance unit 117 and flows through the second pump cell when a constant voltage is applied to the second pump cell 150. The NOx concentration is detected by measuring the current.

Specifically, the exhaust gas in the second measurement chamber 160 is decomposed (reduced) into N ₂ and O ₂ using the sixth electrode 153 of the second pump cell 150 as a catalyst. The decomposed oxygen receives electrons from the sixth electrode 153, flows as oxygen ions in the third solid electrolyte body 151, and moves to the fifth electrode 152. At this time, the residual oxygen remaining in the measurement chamber 107 is also moved into the reference oxygen chamber 170 by the Ip2 cell 150. For this reason, the current flowing through the Ip2 cell 150 is a current derived from NOx and a current derived from residual oxygen.
Here, since the concentration of residual oxygen remaining in the measurement chamber 107 is adjusted to a predetermined value as described above, the current derived from the residual oxygen can be regarded as substantially constant, and the fluctuation of the current derived from NOx. The current flowing through the Ip2 cell 150 is proportional to the NOx concentration.

Next, the electrode pads 301 to 306 of the sensor element 100, which is a characteristic part of the present invention, will be described with reference to FIGS.
3 is a schematic perspective view showing a form in which the through-hole conductor 401 is connected to the electrode pad 301, FIG. 4 is a plan view showing electrode pads 301 to 306 on both surfaces of the main surfaces 100a and 100b of the sensor element 100, and FIG. FIG. 3 is a plan view showing three electrode pads 301 to 303 on one side 100a of the sensor element 100.
The through-hole conductor is formed inside the sensor element 100 in a through hole extending in the thickness direction.

As shown in FIG. 3, the lead portion 110 </ b> L extends from the fourth electrode 110 along the rear end side. The end of the lead portion 110L is connected to a through-hole conductor 401 extending in the thickness direction (stacking direction) inside the protective layer 111, and the through-hole conductor 401 extends to the surface of the protective layer 111. An electrode pad 301 is formed on the surface of the protective layer 111 so as to overlap the through-hole conductor 401.
A portion of the electrode pad 301 that overlaps the through-hole conductor 401 is a connection portion 301c.
The electrode pad 301 can be formed by, for example, printing a conductive paste containing Pt on a predetermined position of the protective layer 111 and then baking it.

Similarly, for each of the other electrodes 104, 106, 108, 152, 153 and the pair of heater lead portions, corresponding electrode pads 302 to 306 are connected to the respective lead portions via through-hole conductors.
As shown in FIG. 4, in this embodiment, on one surface 100 a of the sensor element 100, the electrodes 110 and 104 are connected to the corresponding electrode pads 301 and 303 via the through-hole conductors 401 and 403, respectively. .
The electrodes 108 and 106 are connected to a common electrode pad (ground electrode pad) 302 through the through-hole conductors 402, respectively.

On the opposite surface 100 b of the sensor element 100, the electrode 152 is connected to the corresponding electrode pad 306 through the through-hole conductor 406.
The electrode 153 is connected to a common electrode pad (ground electrode pad) 302 through the through-hole conductor 402.
On the other hand, a pair of heater lead portions from the heating element 10 are connected to corresponding electrode pads 304 and 305 via through-hole conductors 404 and 405, respectively.
The connection portions 301c to 306c of the electrode pads 301 to 306 are overlapping portions with the corresponding through-hole conductors 401 to 406.

Next, the three electrode pads 301 to 303 will be described by taking one side 100a of the sensor element 100 shown in FIG. 5 as an example.
The three electrode pads 301 to 303 include two pad groups 301 and 302 arranged in the width direction, and one single pad 303 arranged with a gap D between the rear ends 301e of the pad groups 301 and 302. The single pad 303 is disposed on the rear end side of the pad groups 301 and 302, and has a gap D in the direction of the axis O with the pad groups 301 and 302.
In the pad groups 301, 302, the electrode pads 301, 302 have a substantially rectangular shape that is long in the direction of the axis O, and the through-hole conductors 401, 402 are disposed on the tip side of the electrode pads 301, 302. Accordingly, the connection portions 301 c and 302 c are also formed on the tip side of the electrode pads 301 and 302.
On the other hand, the single pad 303 has a main body part 303b having a substantially long rectangular shape in the direction of the axis O, and a connection part 303c connected to the through-hole conductor 403 and adjacent to the right side surface of the main body part 303b.
The width of the main body portion 303 b is wider than the gap between the pad groups 301 and 302.
The connection portion 303c is formed integrally with the main body portion 303b in the vicinity of the center (middle) of the side surface of the main body portion 303b as viewed in the direction of the axis O so as to enclose the through-hole conductor 403. Here, the boundary between the main body portion 303b and the connection portion 303c is a position where a line segment parallel to the axis O direction is in contact with the through-hole conductor 403 on the innermost side in the width direction of the single pad 303 (line segment AX in FIG. 5). . In the present embodiment, the main body portions of the pad groups 301 and 302 and the main body portion 303b of the single pad 303 are formed to have substantially the same area.
Further, in the present embodiment, when viewed in the width direction of the single pad 303, the through-hole conductor 403 and the connection portion 303c do not overlap the width direction center Ce of the sensor element 100, that is, the connection portion 303c is closer to the width direction center Ce. Is also located at the end in the width direction.

Further, in the present embodiment, when the length of the pad group 301, 302 having the shorter length in the axis O direction is L1, and the length of the single pad 303 in the axis O direction is L2, L1> L2. The lengths L1 and L2 are the entire lengths of the electrode pads including the connection portions.
In the example of FIG. 5, the lengths of the electrode pads 301 and 302 in the axis O direction are the same.

  Thus, even if the electrode pads 301 and 303 are vertically aligned in the direction of the axis O of the sensor element, the connection portion 303c connected to the through-hole conductor 403 formed in the through hole of the sensor element 100 in the single pad 303. Is adjacent to the side surface of the main body portion 303b, so that the connection portion 303c that does not effectively function as an electrode is prevented from protruding beyond the front portion of the main body portion 303b and a useless space is generated in the direction of the axis O. Compactness can be achieved.

As shown in FIG. 5, in the present embodiment, of the single pad 303, the connection portion 303 c is located in the middle of the axis O direction on the side surface of the main body portion 303 b.
Since the connection portion 303c is connected to the through-hole conductor 403, when the connection portion 303c is located in the middle of the axis O direction on the side surface of the main body portion 303b, the connection portion 303c is the front end surface or the rear end surface of the main body portion 303b. Compared with the case where the connection portion 303c is located, it is easy to connect to the through-hole conductor 403 even if the connection portion 303c is slightly displaced. Further, as described above, since the connection portion 303c does not function effectively as an electrode, the portion overlapping the connection portion 303c in the direction of the axis O becomes a notch 303n to reduce the area of the single pad 303. The amount of Pt used can be reduced, and the cost can be reduced.
Note that the notch 303n may be provided at least one of the front and rear overlapping the connecting portion 303c in the axis O direction.

Further, as shown in FIG. 5, when the width in the width direction of the connection portion 303c of the single pad 303 is W and the total width in the width direction of the single pad 303 is Wp, even if Wp <3.1 × W. Good.
If Wp <3.1 × W, Wp can be made relatively smaller than W, and the amount of Pt used for the single pad 303 can be reduced by that amount, thereby further reducing the cost.
Furthermore, in this embodiment, when L1> L2, even when the electrode pads 301 and 303 are vertically aligned in the direction of the axis O of the sensor element 100, the total length of the electrode pads 301 and 303 is L1 = L2. As a result, the sensor element 100 can be made shorter and more compact.

Further, the distance between the pad groups 301 and 302 in the axis O direction and the single pad 303, that is, the gap D between the rear end 301e of the pad groups 301 and 302 and the tip of the single pad 303 shown in FIG. It is preferable that the equivalent circle diameter of the through-hole conductor 403 is larger than 0.2.
In this way, even if the through-hole conductor 403 is scattered around the through-hole at the time of manufacture, it is possible to further suppress the through-hole conductor 403 from being short-circuited with the pad groups 301 and 302.
Note that the equivalent circle diameter is the equivalent circle diameter of the through-hole conductor 403 on the surface of the element where the single pad 303 is formed, and does not include the through-hole conductor 403 inside the element.

Next, a sensor element according to an embodiment of the second aspect of the present invention will be described with reference to FIG. However, the sensor element according to the embodiment of the second aspect of the present invention is the same as the sensor element according to the embodiment of the second aspect except that the shape of the single pad 313 is different. The description of is omitted.
As shown in FIG. 6, the single pad 313 has a substantially rectangular shape that is long in the direction of the axis O, and is connected to the through-hole conductor 413 so as to enclose the through-hole conductor 413 near the center of the right side of the axis O. .
When the length of the electrode pads of the pad groups 301 and 302 that have a shorter length in the direction of the axis O is L1, and the length of the single pad 313 in the direction of the axis O is L2, L1> L2. The through-hole (through-hole conductor 413) does not overlap with the center in the width direction of the single pad 313.

Even in the sensor element according to the embodiment of the second aspect of the present invention, even if the electrode pads 301 and 303 are arranged vertically in the direction of the axis O of the sensor element 100, the single pad 313 has a through hole in the sensor element 100. Since the portion connected to the formed through-hole conductor 413 is included in the single pad 313, the connection portion to the through-hole conductor 413 that does not function effectively as an electrode protrudes from the front of the single pad 313 and is wasted in the direction of the axis O. It is possible to suppress the generation of a large space and to reduce the size and size of the sensor element 100.
Further, if the through hole (through-hole conductor 413) does not overlap with the center in the width direction of the single pad 313, the connection portion with the through-hole conductor 413 does not intervene on the surface of the single pad 313 near the center in the width direction. All of the single pads 313 can be used as an effective length for reliably contacting the connection terminal 16, and L2 can be reduced accordingly.

The present invention is not limited to the above embodiment, and can be applied to any gas sensor (sensor element) having a sensor element having three electrode pads on at least one side. For example, an oxygen pump cell, an oxygen concentration detection cell, and a heater are used in the present embodiment. The present invention can be applied to the oxygen sensor (oxygen sensor element) of the present invention, but is not limited to these uses, and it goes without saying that the present invention covers various modifications and equivalents included in the spirit and scope of the present invention. For example, the present invention may be applied to a NOx sensor (NOx sensor element) that detects the NOx concentration in the gas to be measured.
The single pad may be disposed apart from the pad group on the front end side of the pad group and the pad group. The shape of the single pad and the pad group, and the position of the connection part (through hole conductor or the like) in the single pad are not limited. The cross-sectional shape of the through-hole conductor is not limited.
The same applies to a via-hole conductor that fills a via hole instead of the through-hole conductor 1200.

DESCRIPTION OF SYMBOLS 1 Gas sensor 16 Connection terminal 30 Main metal fitting 100 Sensor element 100a, 100b Main surface of sensor element 301-306 Electrode pad 301 and 302, 304 and 305 Pad group 303, 306, 313 Single pad 303b, 306b Body part 301c-306c, 313c Connection part 401-406, 413 (Through hole) conductor O Axis line Ce Sensor element width direction center

Claims (8)

A plate-like sensor element extending in the axial direction, having three electrode pads on at least one side of the main surface of the sensor element and each electrode pad being electrically connected to a connection terminal.
On at least one side, a pad group arranged in two in the width direction, and a single pad that is positioned on the front end side or the rear end side of the pad group but does not overlap the pad group when viewed in the width direction, are arranged,
The single pad is wider than a gap between the pad groups, and is connected to a main body portion electrically connected to the connection terminal and a conductor formed in a through hole extending in the thickness direction inside the sensor element. It is a connection part, Comprising: The connection part adjacent to the side surface of the said main-body part, The sensor element characterized by the above-mentioned.   The sensor element according to claim 1, wherein the connection portion is located in the middle of the axial direction on the side surface of the main body portion.   2. The width of the connecting portion of the single pad is W, and the width of the single pad in the width direction is Wp, Wp <3.1 × W. The sensor element according to claim 2.   L1> L2 when the length of the electrode pad of the pad group having the shorter length in the axial direction is L1, and the length of the single pad in the axial direction is L2. The sensor element as described in any one of Claims 1-3. A plate-like sensor element extending in the axial direction, having three electrode pads on at least one side of the main surface of the sensor element and each electrode pad being electrically connected to a connection terminal.
On at least one side, a pad group arranged in two in the width direction, and a single pad that is positioned on the front end side or the rear end side of the pad group but does not overlap the pad group when viewed in the width direction, are arranged,
The single pad is connected to a conductor that is wider than the gap between the pad groups and is formed in a through hole extending in the thickness direction inside the sensor element,
L1> L2 where L1 is the length of the electrode pad of the pad group having the shorter length in the axial direction and L2 is the length of the single pad in the axial direction;
The sensor element according to claim 1, wherein the through hole does not overlap a center in a width direction of the single pad.   The sensor element according to claim 1, wherein the through hole is a through hole, and a conductor is formed in the through hole.   The sensor element according to claim 1, wherein the through hole is a via hole, and a conductor is filled in the via hole. In a gas sensor comprising a sensor element and a metal shell that holds the sensor element,
A gas sensor using the sensor element according to claim 1 as the sensor element.

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