Pressure sensor

Abstract

The present invention provides a pressure sensor having a resistive film pattern that is less susceptible to deformation of an outer bottom surface and is capable of realizing high-precision temperature detection. A pressure sensor is provided with: a base having a bottom wall and a side wall extending in a first direction intersecting the bottom wall; a first resistive film pattern formed in an outer bottom surface of the bottom wall in an outer region overlapping the side wall in plan view from the first direction; and a second resistive film pattern at least partially formed in an inner region of the outer bottom surface that does not overlap the side wall in plan view from the first direction, the first resistive film pattern being configured by folding back and connecting a plurality of circumferential pattern portions that extend in the circumferential direction and have different distances from the center of the outer bottom surface.

Description

Technical Field

[0001] The present invention relates to a pressure sensor using a tube socket. Background Art

[0002] As a sensor such as a pressure sensor, a technique has been proposed in which a resistive film pattern is formed on the outer bottom surface of a metal stem (see Patent Document 1, etc.).

[0003] As a technique for forming a resistive film pattern on the outer bottom surface of a metal stem, a resistive film for temperature detection is formed on the outer region of the outer bottom surface, and a resistive film for pressure detection is formed on the inner region of the outer bottom surface. While the resistance value of the resistive film for pressure detection is also affected by temperature, a pressure sensor with a separate resistive film for temperature detection can eliminate the influence of temperature and determine the pressure value from the output value.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: European Patent Application Publication No. 2554964 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, in conventional pressure sensors, the pattern of the resistive film formed in the outer region of the outer bottom surface is formed by folding back and connecting multiple radially extending radial patterns. Therefore, the output of the resistive film used to detect temperature in conventional pressure sensors is easily affected by deformation of the outer bottom surface, resulting in problems with temperature detection accuracy.

[0009] The present disclosure provides a pressure sensor having a resistive film pattern that is less susceptible to deformation of an outer bottom surface and that can achieve high-precision temperature detection.

[0010] Technical solutions to solve problems

[0011] The present disclosure provides a pressure sensor, comprising:

[0012] a tube base having a bottom wall and a side wall extending in a first direction intersecting with the bottom wall;

[0013] a first resistive film pattern formed in an outer region of the outer bottom surface of the bottom wall that overlaps with the side wall when viewed from the first direction; and

[0014] a second resistive film pattern formed in an inner region of the outer bottom surface that does not overlap with the side wall when viewed from the first direction;

[0015] The first resistive film pattern is formed by folding and connecting a plurality of circumferential pattern portions extending in the circumferential direction and having different distances from the center of the outer bottom surface.

[0016] The pressure sensor disclosed herein includes a first resistive film pattern formed by folding back and connecting portions of a circumferentially extending circumferential pattern. The resistance value of this first resistive film pattern is less susceptible to deformation of the outer bottom surface, enabling highly accurate temperature detection. The outer region of the outer bottom surface tends to deform more radially than circumferentially due to pressure from the measured object.

[0017] Furthermore, because the pressure sensor disclosed herein is constructed by folding back and connecting multiple circumferential pattern sections, it is possible to form a first resistive film pattern with a long conductive length within a limited circumferential angular region. This pressure sensor facilitates miniaturization by easily displacing electrode pads and the like outside the first resistive film pattern, for example. Furthermore, even within a limited range, the length of the first resistive film pattern can be ensured to enable high-precision temperature detection.

[0018] In addition, for example, the angle from one end to the other end of the first circumferential pattern portion located at the outermost periphery among the multiple circumferential pattern portions as viewed from the center may also be larger than the angle from one end to the other end of the other circumferential pattern portions among the multiple circumferential pattern portions except the first circumferential pattern portion as viewed from the center.

[0019] In this pressure sensor, the length of the first circumferential pattern portion, which is least susceptible to deformation of the outer bottom surface, is increased. This effectively reduces the effect of deformation of the outer bottom surface on the resistance value of the first resistive film pattern. Furthermore, because the first resistive film pattern includes other circumferential pattern portions in addition to the first circumferential pattern portion, the entire length of the first resistive film pattern can be ensured for high-precision temperature detection.

[0020] In addition, for example, the side wall may also include a first side wall portion whose inner side surface extends along the first direction, and a second side wall portion whose inner side surface faces the middle of the first side wall portion and the inner bottom surface of the bottom wall and connects the inner side surface of the first side wall portion and the inner bottom surface.

[0021] When viewed from the first direction, at least a portion of the first resistive film pattern may overlap with an inner side surface of the second sidewall portion.

[0022] In this pressure sensor, by arranging a portion of the first resistive film pattern also in the portion of the outer region adjacent to the inner region, the pressure sensor can be further miniaturized while suppressing the influence of deformation of the outer bottom surface.

[0023] In addition, for example, the side wall may also include a first side wall portion whose inner side surface extends along the first direction, and a second side wall portion whose inner side surface faces the middle of the first side wall portion and the inner bottom surface of the bottom wall and connects the inner side surface of the first side wall portion and the inner bottom surface.

[0024] When viewed from the first direction, the entire first resistive film pattern may overlap with the first side wall portion.

[0025] In this pressure sensor, by disposing the entire first resistive film pattern in the portion of the outer region that is less susceptible to deformation of the outer bottom surface, it is possible to achieve higher-precision temperature detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic cross-sectional view of the pressure sensor according to the first embodiment.

[0027] Figure 2 Looking down from the first direction Figure 1 A top view of the pressure sensor is shown.

[0028] Figure 3 It is an explanation Figure 2 A conceptual diagram of the circumferential pattern portion of the first resistive film pattern of the pressure sensor is shown.

[0029] Figure 4 Yes Figure 2 A conceptual diagram illustrating the relationship between the sidewall and outer bottom surface areas of a stem in a pressure sensor.

[0030] Figure 5 Yes Figure 2 A conceptual diagram showing the deformation trend occurring in a pressure sensor.

[0031] Figure 6 is a more detailed description Figure 5 Conceptual diagram showing the deformation trend.

[0032] Figure 7 1 is a conceptual diagram illustrating a circumferential pattern portion of a first resistive film pattern according to a first modification.

[0033] Figure 8 1 is a conceptual diagram illustrating a circumferential pattern portion of a first resistive film pattern according to a second modification.

[0034] Figure 9 1 is a conceptual diagram illustrating a circumferential pattern portion of a first resistive film pattern according to a third modification.

[0035] Figure 10 This is a conceptual diagram showing the relationship between the side wall and the outer bottom surface of the stem in the pressure sensor according to the second embodiment.

[0036] Figure 11 This is a conceptual diagram showing the relationship between the side wall and the outer bottom surface of the stem in the pressure sensor according to the third embodiment.

[0037] Figure 12 This is a schematic diagram of a pressure sensor of a reference example.

[0038] Reference numerals

[0039] 10, 410, 510…pressure sensors

[0040] 12…Connecting parts

[0041] 12a…Thread groove

[0042] 12b…Flow path

[0043] 14…Pressing parts

[0044] 18…Sensor body

[0045] 20, 420, 520...tube socket

[0046] 21…Flange

[0047] 22…bottom wall

[0048] 23, 423, 523…Inner bottom

[0049] 24, 424, 524…outer bottom

[0050] 24a, 424a, 524a…outer area

[0051] 24aa, 424aa, 524aa…outer first area

[0052] 24ab, 424ab, 524ab…the second outer area

[0053] 24e…R deformation area

[0054] 24b, 424b, 524b…inner area

[0055] 24d…θ deformation area

[0056] 24c, 424c, 524c…center

[0057] 25, 425, 525…sidewall

[0058] 25a, 425a, 525a ... first side wall portion

[0059] 26, 426, 526…Inside

[0060] 26a, 426a, 526a…first inner side

[0061] 25b, 425b, 525b...second side wall portion

[0062] 26b, 426b, 526b…second inner side

[0063] 40…Insulation film

[0064] 41, 42, 43, 44, 45, 46, 146, 345, 346... electrode pads 50, 150, 250, 350, 450, 850... first resistive film pattern

[0065] 51, 151, 251, 351, 451…the first circumferential pattern part

[0066] 52, 152, 252, 352, 452…Second circumferential pattern part

[0067] 53, 253, 453…the third circumferential pattern part

[0068] 51a, 52a, 53a, 151a, 152a, 251a, 252a, 253a, 351a, 352a… one end

[0069] 51b, 52b, 53b, 151b, 152b, 251b, 252b, 253b, 351b, 352b…the other end

[0070] θ1, θ2, θ3...angles

[0071] 55, 56, 155, 255, 256, 355...connection

[0072] 60, 560...second resistive film pattern

[0073] R1, R2, R3, R4...resistors

[0074] 90…Circuit board

[0075] 82…Connection wiring

[0076] 850A...resistance film part DETAILED DESCRIPTION

[0077] Hereinafter, the present invention will be described based on the embodiments shown in the drawings.

[0078] First embodiment

[0079] Figure 1 FIG. 1 is a schematic cross-sectional view of the pressure sensor 10 using the stem 20 according to the first embodiment. Figure 1As shown, the pressure sensor 10 includes a base 20 having a bottom wall 22 and side walls 25, and a sensor body 18 provided on the outer bottom surface 24 of the bottom wall 22 via an insulating film 40. The sensor body 18 includes a first resistive film pattern 50 and a second resistive film pattern 60 (see FIG. Figure 2 ).

[0080] like Figure 1 As shown, the tube base 20 has a hollow cylindrical shape and includes a bottom wall 22 and a side wall 25 extending in a first direction D1 intersecting the bottom wall 22. The bottom wall 22 is formed at one end of the side wall 25 in the first direction D1. A portion of the bottom wall 22 (an inner region 24b described later) serves as a diaphragm that deforms in response to the pressure of the fluid being measured.

[0081] On the other hand, the other end of the first direction D1 of the side wall 25 becomes the open end of the hollow portion formed inside the tube base 20. The hollow portion of the tube base 20 is connected to the flow path 12b of the connecting component 12. The first direction D1 in which the side wall 25 extends can be as follows: Figure 1 Although the side walls 25 extend in a direction substantially perpendicular to the outer bottom surface 24 of the bottom wall 22 as shown, the side walls 25 may be inclined so that the hollow portion widens from the bottom wall 22 side toward the opening side.

[0082] like Figure 1 As shown, in pressure sensor 10, fluid introduced into flow path 12b is guided from the hollow portion of tube base 20 to inner bottom surface 23 of bottom wall 22, and fluid pressure acts on inner bottom surface 23 and bottom wall 22. Tube base 20 is made of metal such as stainless steel.

[0083] A flange portion 21 is formed at the other end of the side wall 25 of the tube seat 20. The flange portion 21 is formed to protrude radially outward from the side wall 25. Since the flange portion 21 is sandwiched and fixed between the connecting member 12 and the pressing member 14, the flow path 12b reaching the inner bottom surface 23 of the bottom wall 22 is sealed.

[0084] The connecting member 12 has a threaded groove 12a for connecting the pressure sensor 10 to piping, an external flow path, or the like. The pressure sensor 10 is secured via the threaded groove 12a to, for example, a pressure chamber containing a fluid to be measured. This ensures that the flow path 12b formed within the connecting member 12 and the hollow portion within the tube seat 20 are in airtight communication with the pressure chamber containing the fluid to be measured.

[0085] A circuit board 90 serving as a signal transmission unit is mounted on the upper surface of the pressing member 14. The circuit board 90 has a ring shape surrounding the stem 20, but the shape of the circuit board 90 is not limited thereto. The circuit board 90 includes a sensor main body 18 (see FIG. 1 ) that transmits signals from the stem 20 to the outer bottom surface 24. Figure 2 ) detection signal circuit, etc. The circuit board 90 is connected to the electrode pads 41 to 46 (see Figure 2 ) and other electrical connections.

[0086] Figure 2 yes Figure 1 The top view of the pressure sensor 10 is shown, looking down at the outer bottom surface 24 of the tube base 20 from the first direction D1. Figure 2 As shown, a first resistive film pattern 50 and a second resistive film pattern 60 are formed on the outer bottom surface 24. Figure 2 As shown, the first resistive film pattern 50 is formed in the outer area 24a of the outer bottom surface 24 of the bottom wall 22, and the second resistive film pattern 60 is formed in the inner area 24b of the outer bottom surface 24 of the bottom wall 22 which is closer to the center 24c of the outer bottom surface 24 than the outer area 24a.

[0087] Figure 4 It is an explanation Figure 2 A conceptual diagram of the outer area 24a and the inner area 24b on the outer bottom surface 24 is shown. Figure 4 In the figure, the upper part is configured with a view of the outer bottom surface 24 of the tube seat 20 viewed from the first direction D1, and the lower part of the figure is configured with a sectional view of the tube seat 20 along a section parallel to the first direction D1 and passing through the center 24c of the outer bottom surface 24.

[0088] like Figure 4 As shown, when viewed from the first direction D1, the outer region 24a of the outer bottom surface 24 overlaps the side wall 25 of the stem 20. On the other hand, when viewed from the first direction D1, the inner region 24b of the outer bottom surface 24 does not overlap the side wall 25 of the stem 20.

[0089] like Figure 4 As shown in the cross-sectional view of the tube base 20 in FIG, the side wall 25 includes a first side wall portion 25a having a first inner side surface 26a of the side wall 25 extending in the first direction D1, and a second side wall portion 25b having a second inner side surface 26b of the side wall 25 extending toward the middle between the first inner side surface 26a of the first side wall portion 25a and the inner bottom surface 23 of the bottom wall 22. The second inner side surface 26b of the second side wall portion 25b connects the first inner side surface 26a of the first side wall portion 25a to the inner bottom surface 23.

[0090] The inner surface 26 of the side wall 25 is composed of a first inner surface 26a of the first side wall portion 25a and a second inner surface 26b of the second side wall portion 25b. The first inner surface 26a of the first side wall portion 25a has a substantially cylindrical side surface shape. The second inner surface 26b of the second side wall portion 25b can be formed into an R-shaped rotational surface that is curved when viewed in cross section, or a tapered rotational surface that is straight when viewed in cross section. However, the detailed shape of the second inner surface 26b is not particularly limited.

[0091] like Figure 4 As shown, the outer region 24a of the outer bottom surface 24 includes an outer first region 24aa that overlaps with the first side wall portion 25a when viewed from above, and an outer second region 24ab that overlaps with the second inner side surface 26b of the second side wall portion 25b when viewed from above. The first resistive film pattern 50 shown in the first embodiment entirely overlaps with the first side wall portion 25a when viewed from the first direction D1 and is formed in the outer first region 24aa. By placing the first resistive film pattern 50 entirely in the outer first region 24aa, the problem of the resistance value of the first resistive film pattern 50 being affected by deformation of the bottom wall 22 can be effectively prevented.

[0092] However, an embodiment in which a portion of the first resistive film pattern is formed in the outer second region 24ab is also conceivable (see Figure 10 ) or a portion of the first resistive film pattern is formed in the inner region 24b outside the outer region 24a. In addition, an embodiment is also conceivable in which a portion of the second resistive film pattern 60 is formed in the outer region 24a outside the inner region 24b (for example, the outer second region 24ab). In addition, there may be a portion of the outer bottom surface 24 on the outer edge. Figure 1 、 Figure 4 As for the chamfered portion or the curved portion shown, the plane from the inner portion may be continuous with the outer edge of the outer bottom surface 24 , and such an outer edge portion of the outer bottom surface 24 is also included in the outer bottom surface 24 .

[0093] Figure 2 The second resistive film pattern 60 shown has resistors R1, R2, R3, and R4 formed at predetermined positions on the outer bottom surface 24. The resistance values ​​of the resistors R1 to R4 of the second resistive film pattern 60 change according to the deformation of the bottom wall 22 caused by the pressure of the fluid to be measured. The resistors R1 to R4 of the second resistive film pattern 60 are connected so as to form a Wheatstone bridge circuit. Figure 2 、 Figure 4 In the illustrated example, the resistors R1 to R4 included in the second resistive film pattern 60 are formed inside the entire first resistive film pattern 50 .

[0094] The change in the resistance value of the resistors R1 to R4 of the second resistive film pattern 60 is transmitted to the circuit board 90 (see FIG. 1 ) via the electrode pads 41 , 42 , 43 , and 44 connected to the second resistive film pattern 60 . Figure 1 ) etc. The pressure sensor 10 detects the pressure of the fluid to be measured using the output value of the second resistive film pattern 60. In addition, the number of resistors R1 to R4 of the second resistive film pattern 60 and the specific circuit structure of the second resistive film pattern 60 are not limited to Figure 2 The structure shown can also be set to any number and circuit structure that can detect the deformation of the bottom wall 22.

[0095] Figure 3 and Figure 2 The outer bottom surface 24 of the tube base 20 is also viewed from the first direction D1. Figure 3 In FIG. 1 , the structure other than the first resistive film pattern 50 and the electrode pads 45 and 46 in the sensor main body 18 provided on the outer bottom surface 24 is omitted from illustration.

[0096] like Figure 3 As shown, the first resistive film pattern 50 includes multiple circumferential pattern portions extending in the circumferential direction and having different distances from the center 24c of the outer bottom surface 24, namely, a first circumferential pattern portion 51, a second circumferential pattern portion 52, and a third circumferential pattern portion 53. The first resistive film pattern 50 is formed by folding back and connecting the multiple circumferential pattern portions, namely, the first circumferential pattern portion 51, the second circumferential pattern portion 52, and the third circumferential pattern portion 53. In addition, the first resistive film pattern 50 includes a connecting portion 55 connecting the first circumferential pattern portion 51 and the second circumferential pattern portion 52, and a connecting portion 56 connecting the second circumferential pattern portion 52 and the third circumferential pattern portion 53.

[0097] like Figure 2 As shown, the first circumferential pattern portion 51 is located at the outermost periphery among the plurality of (three in the first embodiment) circumferential pattern portions. The second circumferential pattern portion 52 is arranged closer to the center 24 c of the outer bottom surface 24 than the first circumferential pattern portion 51, and the third circumferential pattern portion 53 is arranged closer to the center 24 c of the outer bottom surface 24 than the first and second circumferential pattern portions 51 and 52.

[0098] like Figure 3 As shown, at least a portion of each of the first circumferential pattern portion 51, the second circumferential pattern portion 52, and the third circumferential pattern portion 53 is arranged concentrically with respect to the center 24c of the outer bottom surface 24. One end 51a of the first circumferential pattern portion 51 is connected to the electrode pad 45. Furthermore, the other end 51b of the first circumferential pattern portion 51 and one end 52a of the second circumferential pattern portion 52 are connected by a substantially semicircular connecting portion 55 having a greater curvature than the circumferential pattern portions 51 and 52.

[0099] Furthermore, the other end 52b of the second circumferential pattern portion 52 and the one end 53a of the third circumferential pattern portion 53 are connected by a roughly semicircular connecting portion 56 having a greater curvature than the circumferential pattern portions 52 and 53. The other end 53b of the third circumferential pattern portion 53 is connected to the electrode pad 46. In this way, in the first resistive film pattern 50, the plurality of circumferential pattern portions 51 and 52 extending in the circumferential direction are connected in such a manner that the conductive path is folded back from left to right when viewed from the one end 51a of the first circumferential pattern portion 51. Furthermore, the plurality of circumferential pattern portions 52 and 53 extending in the circumferential direction are connected in such a manner that the conductive path is folded back from right to left when viewed from the one end 52a of the second circumferential pattern portion 52 by the connecting portion 56.

[0100] like Figure 3 As shown, the angle θ1 from one end 51a to the other end 51b of the first circumferential pattern portion 51 as viewed from the center 24c is larger than the angle θ2 from one end 52a to the other end 52b and the angle θ3 from one end 53a to the other end 53b of the other circumferential pattern portions other than the first circumferential pattern portion 51, namely the second circumferential pattern portion 52 and the third circumferential pattern portion 53 as viewed from the center 24c.

[0101] In this pressure sensor 10, because the length of the first circumferential pattern portion 51, which is least susceptible to deformation, is increased, the effect of deformation of the outer bottom surface 24 on the resistance value change of the first resistive film pattern 50 can be more effectively suppressed. Furthermore, because the first resistive film pattern 50 includes the other circumferential pattern portions 52 and 53 in addition to the first circumferential pattern portion 51, the overall length of the first resistive film pattern 50 can be ensured, thereby improving the accuracy of temperature detection.

[0102] Figure 5 Figure 24 shows the outer bottom surface 24 of the tube seat 20, which includes a region with significant deformation (extension, +) in the θ direction (circumferential direction), and an R deformation region 24e with significant deformation (compression, -) in the R direction (radial direction). The θ deformation region 24d is located near the center 24c of the outer bottom surface 24 and extends toward the interior of the inner region 24b. In contrast, the R deformation region 24e extends toward the boundary between the outer first region 24aa and the outer second region 24ab (inward of the boundary between the outer first region 24aa and the outer second region 24ab).

[0103] Figure 6 This is a graph showing the magnitude of the deformation εθ along the θ direction (circumferential direction) and the magnitude of the deformation εR along the R direction (radial direction) on the outer bottom surface 24 of the stem 20 in correspondence with the position of the outer bottom surface 24. Figure 6It can be understood that in the outer region 24a, the absolute value of the deformation εθ along the θ direction and the absolute value of the deformation εR along the R direction tend to decrease as they go from the inside to the outside. In addition, in the outer region 24a, the absolute value of the deformation εθ along the θ direction tends to be smaller than the absolute value of the deformation εR along the R direction. The resistance values ​​of the plurality of circumferential pattern portions 51, 52, 53 extending in the circumferential direction are not easily affected by the deformation εR along the R direction. Therefore, in Figure 3 In the pressure sensor constructed by folding and connecting a plurality of circumferential pattern portions 51 , 52 , and 53 extending in the circumferential direction as shown, the influence of deformation of the outer bottom surface can be suppressed while the length of the resistance film can be extended, thereby achieving high-precision temperature detection.

[0104] Figure 3 The top-view shapes of the first, second, and third circumferential pattern portions 51, 52, and 53 are arcuate with the center 24c of the outer bottom surface 24 as the center. However, even if they have shapes other than arcuate shapes, as long as they are roughly circumferential, they can be identified as circumferentially extending circumferential pattern portions. For example, regarding a predetermined portion of the first resistive film pattern, if the distance from one end of the portion to the center 24c is R01, the distance from the other end of the portion to the center 24c is R02 (where R01 ≥ R02), and the angle from one end to the other end as viewed from the center 24c is Δθ, then if the following mathematical formula 1 is satisfied, the portion can be identified as a circumferentially extending circumferential pattern portion.

[0105] Δθ / 2π>(R01-R02) / R01···Mathematical formula 1

[0106] The change in the resistance value of the resistor formed by the first resistive film pattern 50 is transmitted to the circuit board 90 (see FIG. 1 ) via the electrode pads 45 and 46 connected to the first resistive film pattern 50. Figure 1 The pressure sensor 10 can perform temperature correction on the output value of the second resistive film pattern 60 using the output value of the first resistive film pattern 50 , for example.

[0107] Examples of materials for the first and second resistive film patterns 50 and 60 include, but are not limited to, metals such as Cr, Ni, Al, and Cu, or conductive strain-sensitive resistive films containing Cr, at least one of Ni, Al, and Cu, and at least one of N and O. The first and second resistive film patterns 50 and 60 are produced, for example, by patterning a strain-sensitive resistive film formed using a thin film method into a predetermined shape. Like the strain-sensitive resistive film, the electrode pads 41 to 46 are also formed from a conductive thin film. Examples of materials for the electrode pads 41 to 46 include metals such as Au, Al, and Ni.

[0108] As described above, the pressure sensor 10 includes a first resistive film pattern 50 formed by folding and connecting circumferential pattern portions 51, 52, and 53 extending in the circumferential direction. The resistance value of this first resistive film pattern 50 is not easily affected by deformation of the outer bottom surface, thereby enabling highly accurate temperature detection. Furthermore, for example, by performing temperature correction on the detection value of the second resistive film pattern 60 based on the detection value of the first resistive film pattern 50, the pressure sensor 10 can perform highly accurate pressure measurement over a wide temperature range.

[0109] Furthermore, because the pressure sensor 10 is constructed by folding and connecting multiple circumferential pattern portions 51, 52, and 53, it is possible to form a first resistive film pattern 50 having a long conductive length within a limited circumferential angular region. This pressure sensor 10 facilitates miniaturization by easily disposing the electrode pads 41 to 46 and the first resistive film pattern 50 offset to the outer region 24a. Furthermore, the length of the first resistive film pattern 50 can be ensured even within a limited range, enabling highly accurate temperature detection.

[0110] In addition, in the pressure sensor 10, as Figure 2 、 Figure 3 and Figure 4 As shown in FIG, since the length of the first circumferential pattern portion 51, which is least susceptible to deformation, is lengthened, the influence of the deformation of the outer bottom surface 24 on the resistance value change of the first resistive film pattern 50 can be more effectively suppressed. However, the shape of the first resistive film pattern of the pressure sensor disclosed in the present invention is not limited to Figure 2 Of course, there are various other variations of the shapes shown.

[0111] Figure 7 1 is a conceptual diagram showing the shape of the first resistive film pattern 150 and its arrangement relative to the outer bottom surface 24 according to the first modification. Figure 7 This is a plan view of the outer bottom surface 24 of the stem 20 as viewed from the first direction D1 , but illustration of the structure of the sensor body provided on the outer bottom surface 24 other than the first resistive film pattern 150 and the electrode pads 45 and 146 is omitted.

[0112] and Figure 2 The first resistive film pattern 50 shown is similarly Figure 7 The first resistive film pattern 150 is also formed on the outer bottom surface 24 and is aligned with the side wall 25 (see FIG. Figure 4 ) overlapping outer area 24a.

[0113] The first resistive film pattern 150 includes a plurality of circumferential pattern portions extending circumferentially and having different distances from the center 24c of the outer bottom surface 24, namely, a first circumferential pattern portion 151 and a second circumferential pattern portion 152. The first resistive film pattern 150 is formed by folding back and connecting the plurality of circumferential pattern portions, namely, the first circumferential pattern portion 151 and the second circumferential pattern portion 152. The first resistive film pattern 150 also includes a connecting portion 155 connecting the first circumferential pattern portion 151 and the second circumferential pattern portion 152.

[0114] The first circumferential pattern portion 151 is located at the outermost periphery of the plurality of (two in the first variant) circumferential pattern portions. At least a portion of each of the first circumferential pattern portion 151 and the second circumferential pattern portion 152 is arranged concentrically with the center 24c of the outer bottom surface 24 as a reference. One end 151a of the first circumferential pattern portion 151 is connected to the electrode pad 45. In addition, the other end 151b of the first circumferential pattern portion 151 and one end 152a of the second circumferential pattern portion 152 are connected by a roughly semicircular connecting portion 155 having a larger curvature than the circumferential pattern portions 151 and 152. The other end 152b of the second circumferential pattern portion 152 is connected to the electrode pad 146.

[0115] The first resistive film pattern 150 has two circumferential pattern portions 151 and 152. The number of circumferential pattern portions is not particularly limited as long as the first resistive film pattern 150 has a plurality of circumferential pattern portions. Furthermore, the first resistive film pattern 150 has a folded portion, i.e., a connecting portion 155. However, the number of folded portions in the first resistive film pattern 150 is not limited to one or two, but may be three or more.

[0116] like Figure 7 As shown, the angle θ1 from one end 151a to the other end 151b of the first circumferential pattern portion 151 as viewed from the center 24c is larger than the angle θ2 from one end 152a to the other end 152b of the other circumferential pattern portion other than the first circumferential pattern portion 151, namely the second circumferential pattern portion 152 as viewed from the center 24c.

[0117] In this first resistance film pattern 150, because the length of the first circumferential pattern portion 151, which is least susceptible to deformation, becomes longer and the proportion of the first circumferential pattern portion 151 in the first resistance film pattern 150 becomes larger, the influence of the deformation of the outer bottom surface 24 on the resistance value change of the first resistance film pattern 150 can be more effectively suppressed.

[0118] The pressure sensor of the present disclosure can be used Figure 7 The first resistive film pattern 150 of the first modified example shown in FIG. Figure 3 The first resistive film pattern 50 is shown. The common points with the pressure sensor 10 are Figure 7 The pressure sensor of the first resistive film pattern 150 also functions as Figures 1 to 6 The same effect is achieved with the pressure sensor 10 shown.

[0119] Figure 8 1 is a conceptual diagram showing the shape of the first resistive film pattern 250 and its arrangement relative to the outer bottom surface 24 according to the second modification. Figure 8 This is a plan view of the outer bottom surface 24 of the stem 20 as viewed from the first direction D1 , but illustration of the structure of the sensor body provided on the outer bottom surface 24 other than the first resistive film pattern 250 and the electrode pads 45 and 46 is omitted.

[0120] and Figure 2 The first resistive film pattern 50 shown is similarly Figure 8 The first resistive film pattern 250 is also formed on the outer bottom surface 24 and is aligned with the side wall 25 (see FIG. Figure 4 ) overlapping outer area 24a.

[0121] The first resistive film pattern 250 includes a plurality of circumferential pattern portions extending circumferentially and having different distances from the center 24c of the outer bottom surface 24, namely, a first circumferential pattern portion 251, a second circumferential pattern portion 252, and a third circumferential pattern portion 253. The first resistive film pattern 250 is formed by folding back and connecting the plurality of circumferential pattern portions, namely, the first circumferential pattern portion 251, the second circumferential pattern portion 252, and the third circumferential pattern portion 253. Furthermore, the first resistive film pattern 250 includes a connecting portion 255 connecting the first circumferential pattern portion 251 and the second circumferential pattern portion 252, and a connecting portion 256 connecting the second circumferential pattern portion 252 and the third circumferential pattern portion 253.

[0122] The third circumferential pattern portion 253 is located at the innermost periphery of the plurality of (three in the second variant) circumferential pattern portions. Each of the first circumferential pattern portion 251, the second circumferential pattern portion 252, and at least a portion of the third circumferential pattern portion 253 is arranged concentrically with the center 24c of the outer bottom surface 24 as a reference. One end 251a of the first circumferential pattern portion 251 is connected to the electrode pad 45. Furthermore, the other end 251b of the first circumferential pattern portion 251 and one end 252a of the second circumferential pattern portion 252 are connected by a roughly semicircular connecting portion 255 having a greater curvature than the circumferential pattern portions 251 and 252.

[0123] The other end 252b of the second circumferential pattern portion 252 and one end 253a of the third circumferential pattern portion 253 are connected by a substantially semicircular connecting portion 256 having a greater curvature than the circumferential pattern portions 252 and 253. The other end 253b of the third circumferential pattern portion 253 is connected to the electrode pad 46.

[0124] like Figure 8 As shown, the angle θ3 from one end 253a to the other end 253b of the third circumferential pattern portion 253 observed from the center 24c is larger than the angle θ1 from one end 251a to the other end 251b and the angle θ2 from one end 252a to the other end 252b of the other circumferential pattern portions other than the third circumferential pattern portion 253, namely the first circumferential pattern portion 251 and the second circumferential pattern portion 252 observed from the center 24c.

[0125] In the first resistive film pattern 250 , the length of the third circumferential pattern portion 253 closest to the inner region 24 b where the second resistive film pattern 60 is configured is increased, so that the error between the temperature detected in the first resistive film pattern 250 and the actual temperature of the second resistive film pattern 60 can be reduced.

[0126] The pressure sensor of the present disclosure can be used Figure 8 The first resistive film pattern 250 of the second modified example shown in FIG. Figure 3 The first resistive film pattern 50 is shown. The common points with the pressure sensor 10 are Figure 8 The pressure sensor of the first resistive film pattern 250 also functions as Figures 1 to 6 The same effect is achieved with the pressure sensor 10 shown.

[0127] Figure 9 1 is a conceptual diagram showing the shape of the first resistive film pattern 350 and its arrangement relative to the outer bottom surface 24 according to the third modification. Figure 9 This is a plan view of the outer bottom surface 24 of the stem 20 as viewed from the first direction D1 , but the structure other than the first resistive film pattern 350 and the electrode pads 345 and 346 in the sensor body provided on the outer bottom surface 24 is omitted.

[0128] and Figure 3 The first resistive film pattern 50 shown is similarly Figure 9 The first resistive film pattern 350 is also formed on the outer bottom surface 24 and is aligned with the side wall 25 (see FIG. Figure 4 ) overlapping outer area 24a.

[0129] The first resistive film pattern 350 includes multiple circumferential pattern portions extending circumferentially and having different distances from the center 24c of the outer bottom surface 24, namely, a first circumferential pattern portion 351 and a second circumferential pattern portion 352. The first resistive film pattern 350 is formed by folding back and connecting the multiple circumferential pattern portions, namely, the first circumferential pattern portion 351 and the second circumferential pattern portion 352. The first resistive film pattern 350 also includes a connecting portion 355 that connects the first circumferential pattern portion 351 and the second circumferential pattern portion 352.

[0130] The second circumferential pattern portion 352 is located at the innermost circumference of the plurality of (two in the first variant) circumferential pattern portions. At least a portion of each of the first circumferential pattern portion 351 and the second circumferential pattern portion 352 is arranged concentrically with the center 24c of the outer bottom surface 24 as a reference. One end 351a of the first circumferential pattern portion 351 is connected to the electrode pad 345. In addition, the other end 351b of the first circumferential pattern portion 351 and one end 352a of the second circumferential pattern portion 352 are connected by a roughly semicircular connecting portion 355 with a greater curvature than the circumferential pattern portions 351 and 352. The other end 352b of the second circumferential pattern portion 352 is connected to the electrode pad 346.

[0131] like Figure 9 As shown, the angle θ2 from one end 352a to the other end 352b of the second circumferential pattern portion 352 as viewed from the center 24c is larger than the angle θ1 from one end 351a to the other end 351b of the other circumferential pattern portions other than the second circumferential pattern portion 352, namely the first circumferential pattern portion 351 as viewed from the center 24c.

[0132] In this first resistance film pattern 350, because the length of the second circumferential pattern portion 352 close to the inner area 24b where the second resistance film pattern 60 is configured becomes longer and the proportion of the second circumferential pattern portion 352 in the first resistance film pattern 350 becomes larger, the error between the temperature detected in the first resistance film pattern 350 and the actual temperature of the second resistance film pattern 60 can be reduced.

[0133] The pressure sensor of the present disclosure can be used Figure 9 The first resistive film pattern 350 of the third modified example shown in FIG. Figure 3 The first resistive film pattern 50 is shown. The common points with the pressure sensor 10 are Figure 9 The pressure sensor of the first resistive film pattern 350 also functions as Figures 1 to 6 The same effect is achieved with the pressure sensor 10 shown.

[0134] Second embodiment

[0135] Figure 10 4 is a conceptual diagram illustrating the arrangement of the outer area 424a and the inner area 424b on the outer bottom surface 424 of the pressure sensor 410 according to the second embodiment of the present disclosure, as well as the first resistive film pattern 450 and the second resistive film pattern 60. Figure 10 In the figure, the upper part is provided with a view of the outer bottom surface 424 of the tube seat 420 viewed from the first direction D1, and the lower part of the figure is provided with a sectional view of the tube seat 420 along a section parallel to the first direction D1 and passing through the center 424c of the outer bottom surface 424.

[0136] Figure 10 The thickness of the side wall 425 of the base 420 of the pressure sensor 410 is shown to be greater than Figure 4 The sidewall 25 shown is thin and a portion of the first resistive film pattern 450 is disposed in the outer second region 424ab. Figure 4 The pressure sensor 410 is different from the pressure sensor 10 shown in FIG. 1 , but is otherwise identical to the pressure sensor 10. The description of the pressure sensor 410 focuses on the differences from the pressure sensor 10. The same reference numerals are used for the common points with the pressure sensor 10, and the description thereof is omitted.

[0137] like Figure 10 As shown, Figure 4 Compared to the illustrated pressure sensor 10, the base 420 of the pressure sensor 410 has a thinner sidewall 425, and the area of ​​the outer region 424a on the outer bottom surface 424, particularly the outer first region 424aa within the outer region 424a, is reduced. Consequently, a portion of the first resistive film pattern 450, particularly the innermost third circumferential pattern portion 453 of the first to third circumferential pattern portions 451, 452, and 453, is formed within the outer second region 424ab of the outer region 424a.

[0138] like Figure 10 As shown, the side wall 425 includes a first side wall portion 425a extending along the first direction D1 at a first inner side surface 426a of the side wall 425, and a second side wall portion 425b directed toward a center between the first side wall portion 425a and the inner bottom surface 423 of the bottom wall 22. The second inner side surface 426b of the second side wall portion 425b connects the first inner side surface 426a of the first side wall portion 425a to the inner bottom surface 423.

[0139] When viewed from the first direction D1, a portion of the first resistive film pattern 450, namely the third circumferential pattern portion 453, is formed in the outer second region 424ab overlapping the second inner side surface 426b of the second side wall portion 425b. Figure 3 The first resistive film patterns 50 shown are the same.

[0140] Here, if Figure 6 As shown, the outer second regions 424ab and 24ab partially overlap with the R deformation region 24e, and there is a tendency that the deformation (compression, -) along the R direction (radial direction) is large, but the deformation (tension, +) along the θ direction (circumferential direction) is small. Figure 10In the illustrated first resistive film pattern 450, only the third circumferential pattern portion 453 extending circumferentially is formed in the outer second region 424ab. Thus, even if at least a portion of the first resistive film pattern 450 is formed in the outer second region 424ab, as long as only or most of the portion extends circumferentially, the resistance value of the first resistive film pattern 450 is not easily affected by deformation of the outer bottom surface.

[0141] In this way, with Figure 4 The pressure sensor 10 of the first resistive film pattern 50 shown in FIG. Figure 10 The pressure sensor 410 of the first resistive film pattern 450 can also suppress the influence of the deformation of the outer bottom surface 424 and further reduce the size of the pressure sensor 410. Figure 10 The illustrated pressure sensor 410 performs the same function as the pressure sensor 10 .

[0142] Third embodiment

[0143] Figure 11 : is a conceptual diagram illustrating the arrangement of the outer area 524a and the inner area 524b on the outer bottom surface 524 of the pressure sensor 510 according to the third embodiment of the present disclosure, as well as the first resistive film pattern 50 and the second resistive film pattern 560. Figure 11 In the figure, the upper part is provided with a view of the outer bottom surface 524 of the tube seat 520 viewed from the first direction D1, and the lower part of the figure is provided with a cross-sectional view of the tube seat 520 along a section parallel to the first direction D1 and passing through the center 524c of the outer bottom surface 524.

[0144] Figure 11 The thickness of the side wall 525 of the base 520 of the pressure sensor 510 is shown to be greater than Figure 4 The sidewall 25 shown is thick and a portion of the second resistive film pattern 560 is arranged in the outer second region 524ab. Figure 4 The pressure sensor 510 is different from the pressure sensor 10 shown in FIG. 1 , but is otherwise identical to the pressure sensor 10. The description of the pressure sensor 510 focuses on the differences from the pressure sensor 10. The same reference numerals are used for the common points with the pressure sensor 10, and the description thereof is omitted.

[0145] like Figure 11 As shown, Figure 4Compared to the illustrated pressure sensor 10, the base 520 of the pressure sensor 510 has a thicker sidewall 525, which increases the area of ​​the outer first region 524aa on the outer bottom surface 524, while reducing the area of ​​the inner region 524b. Consequently, a portion of the second resistive film pattern 560, particularly a portion of the resistors R3 and R4, is formed in the outer second region 524ab of the outer region 524a.

[0146] like Figure 11 As shown, the side wall 525 includes a first side wall portion 525a extending along the first direction D1 at a first inner side surface 526a of the side wall 525, and a second side wall portion 525b oriented toward a center between the first side wall portion 525a and the inner bottom surface 523 of the bottom wall 22. The second inner side surface 526b of the second side wall portion 525b connects the first inner side surface 526a of the first side wall portion 525a to the inner bottom surface 523.

[0147] When viewed from the first direction D1, a portion of the resistors R3 and R4 of the second resistive film pattern 560 is formed in the outer second region 524ab overlapping the second inner side surface 526b of the second sidewall portion 525b. Figure 4 The second resistive film patterns 60 shown are the same.

[0148] Here, if Figure 6 As shown, the outer second regions 524ab and 24ab partially overlap with the R deformation region 24e, and there is a tendency for deformation (compression, -) along the R direction (radial direction) to be large. Figure 6 It can be understood that even if a portion of the resistors R3 and R4 of the second resistive film pattern 560 is formed in the outer second region 524 ab , the deformation of the outer bottom surface 524 can still be appropriately detected.

[0149] In addition, regarding the common points with the pressure sensor 10, Figure 11 The illustrated pressure sensor 510 performs the same function as the pressure sensor 10 .

[0150] The pressure sensor of the present disclosure is described in more detail below with reference to examples, but these examples do not limit the pressure sensor of the present disclosure.

[0151] The outer bottom surface 24 of the tube base 20 is provided with a Figure 3 The pressure sensor 10 having the first resistive film pattern 50 shown in FIG. 1 is used as an embodiment model. On the other hand, a resistive film pattern 50 is formed on the outer bottom surface 24 of the stem 20. Figure 12The pressure sensor having the first resistive film pattern 850 shown is used as a reference example model. The reference example pressure sensor is identical to the pressure sensor 10 in parts other than the first resistive film pattern 850 .

[0152] and Figure 3 The first resistive film pattern 50 shown is the same as Figure 12 The first resistive film pattern 850 shown connects the electrode pad 45 and the electrode pad 46. However, unlike the first resistive film pattern 50, the first resistive film pattern 850 has a plurality of resistive film portions 850a extending in the radial direction (R direction), and is formed by folding back and connecting the plurality of resistive film portions 850a formed radially from the center 24c.

[0153] One end of the first resistive film pattern 850 is connected to the electrode pad 45, and the other end is connected to the electrode pad 46. The angle θ between one end and the other end of the first resistive film pattern 850 as viewed from the center 24c is Figure 3 The angles of the first resistive film pattern 50 from one end to the other as viewed from the center 24c are the same. In addition, the length, number and spacing of the resistive film portions 850a constituting the first resistive film pattern 850 are determined so that Figure 12 The length and resistance value of the first resistive film pattern 850 are the same as those of the first resistive film pattern 50 .

[0154] Furthermore, simulations were performed on the pressure sensor 10 of the embodiment model having the first resistive film pattern 50 and the pressure sensor of the reference example model having the first resistive film pattern 850 to calculate the amount of change in resistance of the first resistive film patterns 50 and 850 when pressure was applied. The simulation results showed that the amount of change in resistance of the pressure sensor 10 of the embodiment model having the first resistive film pattern 50 when pressure was applied was approximately half that of the pressure sensor of the reference example model having the first resistive film pattern 850.

[0155] As described above, the pressure sensor of the present disclosure has been described by way of embodiments, variations, and examples. However, the technical scope of the pressure sensor of the present disclosure is not limited to these embodiments, variations, and examples, and of course includes many other embodiments or variations. For example, other resistive film patterns other than the first resistive film pattern or the second resistive film pattern may be formed on the outer bottom surface of the pressure sensor. In addition, the top view shape of the connecting portion connecting the plurality of circumferential pattern portions is not limited to Figure 3 The arc shape shown may be, for example, a connecting portion that linearly connects a plurality of circumferential pattern portions, and the connecting portion may have a width different from that of the circumferential pattern portion.

Claims

1. A pressure sensor, wherein: have: a tube base having a bottom wall and a side wall extending in a first direction intersecting with the bottom wall; a first resistive film pattern formed in an outer region of the outer bottom surface of the bottom wall that overlaps with the side wall when viewed from the first direction; as well as The second resistive film pattern is at least partially formed in an inner region of the outer bottom surface that does not overlap with the side wall when viewed from the first direction. The first resistive film pattern is formed by folding and connecting a plurality of circumferential pattern portions extending in the circumferential direction and having different distances from the center of the outer bottom surface.

2. The pressure sensor according to claim 1, wherein The angle from one end to the other end of the first circumferential pattern portion located at the outermost periphery among the multiple circumferential pattern portions as viewed from the center is larger than the angle from one end to the other end of the other circumferential pattern portions among the multiple circumferential pattern portions except the first circumferential pattern portion as viewed from the center.

3. The pressure sensor according to claim 1 or 2, wherein: The side wall includes a first side wall portion whose inner side surface extends along the first direction, and a second side wall portion whose inner side surface faces the middle of the first side wall portion and the inner bottom surface of the bottom wall and connects the inner side surface of the first side wall portion and the inner bottom surface. When viewed from the first direction, at least a portion of the first resistive film pattern overlaps with an inner side surface of the second sidewall portion.

4. The pressure sensor according to claim 1 or 2, wherein: The side wall includes a first side wall portion whose inner side surface extends along the first direction, and a second side wall portion whose inner side surface faces the middle of the first side wall portion and the inner bottom surface of the bottom wall and connects the inner side surface of the first side wall portion and the inner bottom surface. When viewed from the first direction, the entire first resistive film pattern partially overlaps with the first sidewall.

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