JP2001242032A - Sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hardly fluctuate sensor characteristics of a sensor main fixed to a case. SOLUTION: This sensor provided with a box case 13 having an opening and fixed to the inside so as to position the sensor body 1 in the opening side, and a cover 16 covering the opening of the case 13 is so constituted that an engagement counterpart 13f to be engaged with an engagement part 16c is provided in the cover 16 so as to provide the case 13 with elasticity along with the rigidity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a sensor such as a pressure sensor.

[0002]

2. Description of the Related Art Conventionally, this type of sensor has been disclosed in
There is one disclosed in Japanese Patent Application No. 0-332517. As shown in FIG. 14, this pressure sensor includes a case B having an opening and fixing a semiconductor sensor chip (sensor main body) A, and a cover C closing the opening of the case B. The case B is provided with a claw-shaped engaging portion B1 having elasticity. The engaging portion B1 is engaged with a hole-shaped engaged portion C1 provided on the cover C by a so-called snap-fit. At the same time, the opening of the case B is covered with the cover C.

The semiconductor sensor chip has a thin diaphragm for pressure detection formed on a silicon substrate and a pressure detection circuit integrally provided on the upper surface thereof.

[0004]

In the above-mentioned conventional sensor, when the engaging portion B1 provided on the case B engages with the engaged portion C1 of the cover C due to its elasticity, the engaging portion B1 engages with the engaging portion B1. Distortion will occur in the joint B1. Here, if the engaging portion B1 of the case B is engaged with the engaged portion C1 of the cover C by an unnecessarily strong external force, the distortion generated in the engaging portion B1 increases. If it extends over the entire case B, even the semiconductor sensor chip A fixed to the case B is affected by the distortion,
The characteristics of the semiconductor sensor chip A may fluctuate.

The present invention has been made in view of the above points, and an object of the present invention is to provide a sensor in which the sensor characteristics of a sensor body fixed to a case hardly fluctuate.

[0006]

According to a first aspect of the present invention, there is provided a sensor having a box-shaped case having an opening and having a sensor main body fixed inside so as to be positioned on the opening side. A cover that closes an opening of the case, wherein the case has rigidity,
A configuration is provided in which an engaged portion that is engaged with an engaging portion provided on the cover so as to have elasticity is provided.

According to a second aspect of the present invention, in the sensor according to the first aspect, the cover is provided with a mounting portion for external mounting, and the mounting portion is configured to be substantially equal to the engaging portion. I have.

According to a third aspect of the present invention, in the sensor according to the first aspect, the cover is provided with a mounting portion for external mounting, and is formed between the case and the cover near the mounting portion. The gap is locally enlarged.

According to a fourth aspect of the present invention, in the sensor according to the second or third aspect, a gap is formed between the case and the cover near the engaging portion of the cover. Is locally reduced.

According to a fifth aspect of the present invention, in the sensor according to the first aspect, a circuit board for processing a signal from the sensor body and a sensor element for supporting the sensor body are fixed inside the case. The cover is configured to be attached to the outside and to have a restricting portion on the opening side of the case, which restricts the circuit board from being displaced toward the opening of the case.

According to a sixth aspect of the present invention, in the sensor according to the fifth aspect, the circuit board is provided with a detection circuit for detecting distortion of the circuit board itself.

According to a seventh aspect of the present invention, in the sensor according to the first aspect, a circuit board for processing a signal from the sensor body and a sensor element for supporting the sensor body are fixed inside the case. The cover is attached to the outside and has a pressing portion on the opening side of the case that presses the circuit component when the circuit component mounted on the circuit board is displaced toward the opening of the case. ing.

[0013] According to an eighth aspect of the present invention, in the sensor according to any one of the first to seventh aspects, the sensor main body is a semiconductor sensor chip.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sensor according to a first embodiment of the present invention will be described below with reference to FIGS. This sensor is, for example, a pressure sensor used for detecting a gas leak of a household gas meter. It is not limited to this use.

Reference numeral 1 denotes a semiconductor sensor chip as a sensor main body, which is made of, for example, single-crystal silicon and has a thin-walled diaphragm (not shown) integrated therewith, and, for example, four diffusion layers are provided on the upper surface of the diaphragm. A detection circuit is formed by bridge-connecting piezoresistors (not shown). This semiconductor sensor chip 1 is joined and supported on a pedestal 2 made of glass or the like.
The pedestal 2 is fixed to a pipe 3 described later by bonding or the like.

Reference numeral 3 denotes a pipe having a through hole 3a vertically penetrated so as to introduce pressure to the diaphragm, and is fixed to the molded body 5 together with the terminal plate 4 by, for example, simultaneous molding. The terminal plate 4 is wire-bonded to the semiconductor sensor chip 1 by wires 6. Reference numeral 7 denotes a lid which is mounted on the molded body 5 and protects the semiconductor sensor chip 1 from dust and the like. The lid 7, together with the pedestal 2, the pipe 3, the terminal plate 4 and the molded body 5, form a sensor element 8 that supports the semiconductor sensor chip 1. The sensor element 8 forms an element block 9 together with the semiconductor sensor chip 1. This element block 9
The circuit board 12 including the circuit board 10 is connected to the circuit board 10 by soldering the terminal board 4 to be described later.
Is electrically connected to

Reference numeral 10 denotes a circuit board, and a semiconductor sensor chip 1
The electronic component (circuit component) 11 for signal processing is mounted, and a circuit block 12 is formed together with the mounted electronic component 11. The circuit board 10 has an insertion hole 10a into which the terminal plate 4 of the element block 9 and a lead 15 described later are inserted and soldered.
And a fixing hole 10b into which a protrusion of a case 13 described later is inserted and fixed by thermal caulking.

Reference numeral 13 denotes a case, which is formed in a box shape having a substantially elliptical shape in plan view and having an opening on one side, and a protruding tube having a pressure introduction port 13a at its tip and a hollow portion communicating with the internal space 13b. 13c is provided integrally. This case 13
Are protrusions 13d which are inserted into the fixing holes 10b of the circuit board 10 at the opening edges thereof to fix the circuit board 10 by thermal caulking.
Is provided. The side portion of the case 13 has a thick portion 13 which is rigid enough to prevent elastic deformation such as falling inward.
e, and a cover 16 to be described later is provided outside the side portion.
A protruding engaged portion 13f to be engaged with the engaging portion 16c is provided.

The above-described element block 9 is housed in the internal space 13b of the case 13, and an O-ring 14 is provided between the element block 9 and the case 13 in order to maintain airtightness against a fluid whose pressure is detected. Will be arranged. Element block 9 stored in this case 13
Is fixed to the case 13 as described above, so that the element block 9 is also fixed to the case 13.

Reference numeral 15 denotes a lead, which is used for power input and signal output, and is fixed to the case 13 by press-fitting or the like. The lead 15 is formed in a substantially U-shape. One end of the lead 15 penetrates through an insertion hole 16 a of a cover 16 to be described later to the outside, and the other end penetrates the insertion hole 10 a of the circuit board 10. Is connected to the circuit board 10.

Reference numeral 16 denotes a cover, which is formed in a substantially oval box shape in plan view having an opening on one side, and has an insertion hole 16a for inserting the lead 15 and an opening 16b for opening to the atmosphere at the bottom. Is provided. The side of the cover 16 is
It is formed so thin that it can be elastically deformed, and has a hole-like engaging portion 16c that engages with the engaged portion 13f of the case 13 at both ends in the long axis direction.

As described above, the case 13
f, and the cover 16 is provided with the engaging portion 16c, so that the opening of the case 13 is closed so that the cover 16 and the case 13 have a slight gap on each side. In the state of being overlapped, the engaging portion 16c of the cover 16 is
The so-called snap-fit engagement is achieved with the elasticity described above.

The cover 16 is mounted on a mounting object 18 by passing screws 17 through hole-shaped mounting portions 16d provided at both ends of the opening edge in the short direction. This cover 16
Since the engagement portions 16c are provided at both ends in the long axis direction and the attachment portions 16d are provided at both end portions in the short direction, the distance between the engagement portion 16c and the attachment portion 16d is equal.

This is assembled according to the procedures shown in FIGS. 6 (a) to 6 (d). That is, first, as shown in FIG. 3A, the lead 15 is press-fitted into the case 13, and then the sensor element 8 forming the element block 9 is housed together with the semiconductor chip 1. Fixed,
Finally, the cover 13 is engaged with the case 13 and assembled.

In this sensor, when the engaging portion 16c provided on the cover 16 engages with the engaged portion 13f of the case 13 due to the elasticity of the cover 16, the engaging portion 16c has elasticity. Even if the cover 16 provided with the elastic member is distorted, the distortion is absorbed by the cover 16 and the distortion is not transmitted to the engaged portion 13 f of the rigid case 13. The influence of the distortion at the time of engagement is not transmitted to the sensor chip 1, and the sensor characteristics of the semiconductor sensor chip 1 are less likely to fluctuate.

The mounting portion 1 mounted on the mounting object 18
6d may be distorted due to mounting, but the mounting portion 16
d and the engaging portion 16c are substantially equal, so that the mounting portion 16d
There is no particularly small portion between the semiconductor chip and the engaging portion 16 c, and the distortion accompanying the attachment is difficult to be transmitted, and the distortion at the time of attachment generated on the cover 16 is not transmitted to the case 13. The effect of distortion at the time of mounting is not transmitted to the sensor chip 1, and the effect that the sensor characteristics of the semiconductor sensor chip 1 hardly fluctuate can be further exhibited.

Further, since the sensor body is the semiconductor sensor chip 1, the detection accuracy can be increased.

Next, a sensor according to a second embodiment of the present invention will be described below with reference to FIG. Parts having substantially the same functions as those of the first embodiment are denoted by the same reference numerals,
Only different points from the first embodiment will be described. In this embodiment,
Basically, it is the same as the first embodiment, except that the cover 16
7, the gap 20 between the case 13 and the cover 16 is locally increased in the vicinity of the mounting portion 16d, that is, in the vicinity of both ends in the short direction.
6, the gap between the case 13 and the cover 16 is locally reduced near the engaging portion 16c, that is, near both ends in the longitudinal direction.

In such a sensor, even if the vicinity of the mounting portion 16d of the cover 16 is deformed when the mounting portion 16d of the cover 16 is mounted on the mounting object 18, the case 13 and the case 13 are not positioned near the mounting portion 16d. Since the space 20 formed between the cover 16 and the cover 13 is locally large and the case 13 is not deformed due to the deformation of the cover 16 during mounting, the semiconductor sensor chip fixed to the case 13 1, the effect of attaching the cover 16 is not transmitted, and the effect that the sensor characteristics of the semiconductor sensor chip 1 hardly fluctuate can be further obtained.

In the vicinity of the engaging portion 16c of the cover 16, the gap formed between the case 13 and the cover 16 is locally reduced, so that the displacement caused by the engagement is minimized. Can be.

Next, a sensor according to a third embodiment of the present invention will be described below with reference to FIGS. Note that portions having substantially the same functions as those of the first embodiment are denoted by the same reference numerals, and only the differences from the first embodiment will be described. This embodiment is basically the same as the second embodiment,
The cover 16 is provided with a protruding restricting portion 16e facing the circuit board 10 at a location facing the circuit board 10 with a slight gap between the circuit board 10 and the circuit board 10. A detection circuit (not shown) for detecting distortion of the substrate 10 itself is provided.

In this case, the circuit board 10 fixed to the case 13 by thermal caulking applies, for example, an external force that causes the circuit board 10 to separate from the case 13 when the pressure of the fluid whose pressure is detected is very high. Therefore, even if the fixing to the case 13 is loosened and the circuit board 10 is displaced toward the opening of the case 13, the circuit board 10
It is limited that the cover 16 is pressed down by the restricting portion 16e and displaced toward the opening of the case 13.
In addition, since the cover 16 is attached to and fixed to the mounting target 18, the circuit board 10 is restricted from separating from the case 13 unless the cover 16 is separated from the mounting target 18.

In such a sensor, in addition to the effect of the sensor of the first embodiment, since the circuit board 10 is restricted from being separated from the case 13 by the restricting portion 16e provided on the cover 16, Even if the fixing is loosened, it will not be separated.

The cover 1 is separated from the case 13.
6 is restricted by the restricting portion 16e provided in the circuit board 1
Even if 0 is distorted, since the distortion of the circuit board 10 is detected by the detection circuit provided on the circuit board 10, the circuit board 10 may be distorted before the circuit board 10 is damaged by the distortion. Can be detected.

Next, a sensor according to a fourth embodiment of the present invention will be described below with reference to FIGS. The third
Portions having substantially the same functions as those of the third embodiment are denoted by the same reference numerals, and only differences from the third embodiment will be described. In the third embodiment, the cover 16 is provided with a protruding restricting portion 16e facing the circuit board 10 at a position facing the circuit board 10 with a slight gap therebetween. Is provided with a detection circuit for detecting the distortion of the circuit board 10 itself, whereas in the present embodiment, a protruding pressing portion 16f opposed to the electronic component 11 with a slight gap is provided. Is provided.

In this case, the circuit board 10 fixed to the case 13 by thermal caulking applies, for example, an external force that causes the circuit board 10 to separate from the case 13 when the pressure of the fluid whose pressure is detected is very high. When the fixing to the case 13 is loosened and the circuit board 10 is displaced toward the opening of the case 13, the electronic component 11 mounted on the circuit board 10 is pressed by the pressing portion 16 f of the cover 16. Then, normal operation stops. For example, circuit component 1
When 1 is an amplifier for amplifying the output of the semiconductor sensor chip 1, an abnormality occurs in the gain of the output of the semiconductor sensor chip 1.

In such a sensor, in addition to the effects of the sensor of the first embodiment, the circuit board 10
When the circuit board 10 is displaced toward the opening of the case when the fixing of the
6f presses the electronic component 11 mounted on the circuit board 10 and hinders the normal operation of the circuit component 11, so that the circuit board 10 is displaced toward the opening of the case 13. As a result, the loosening of the fixing of the circuit board 10 by the case 13 can be detected.

In the third and fourth embodiments, similarly to the first embodiment, the mounting portion 16d of the cover 16 is provided.
1 and the vicinity of the engaging portion 16c of the cover 16,
The gap between the cover 3 and the cover 16 is substantially the same as the other portions, but as in the second embodiment, the mounting portion 1
In the vicinity of 6d, the gap between the case 13 and the cover 16 is locally increased, so that the effect of attaching the cover 16 to the semiconductor sensor chip 1 fixed to the case 13 is not transmitted. The effect that the sensor characteristics of the sensor chip 1 hardly fluctuate can be further exhibited, and the gap between the case 13 and the cover 16 is locally reduced near the engaging portion 16c of the cover 16. Accordingly, it is possible to achieve an effect that the displacement due to the engagement can be minimized.

Although the sensors of the first to fourth embodiments are pressure sensors, other sensors such as an acceleration sensor can provide the same effect.

[0040]

According to the sensor of the first aspect, when the engaging portion provided on the cover engages with the engaged portion of the case due to its elasticity, distortion occurs in the elastic engaging portion. Even
Since the distortion is absorbed by the cover, the distortion is not transmitted to the engaged portion of the rigid case, so that the sensor body fixed to the case is not affected by the distortion at the time of engagement, The sensor characteristics of the sensor body hardly fluctuate.

In the sensor according to the second aspect of the present invention, the mounting portion to be mounted on the mounting object may be distorted due to the mounting, but since the distance between the mounting portion and the engaging portion is substantially equal, the mounting portion is engaged with the mounting portion. Since there is no particularly small part between the parts, the distortion during mounting is difficult to be transmitted, and the distortion generated during mounting on the cover is not transmitted to the case, so the sensor body fixed to the case has The effect of the sensor according to claim 1, in which the influence of distortion is not transmitted, and the sensor characteristics of the sensor main body are less likely to fluctuate can be further exhibited.

According to the third aspect of the present invention, even if the vicinity of the mounting portion of the cover is deformed when the mounting portion of the cover is mounted outside, the sensor is formed between the case and the cover near the mounting portion. Since the air gap is locally large and the case is not deformed due to the deformation of the cover at the time of mounting, the effect of the cover at the time of mounting the cover is transmitted to the sensor body fixed to the case. Therefore, the effect of the sensor according to the first aspect that the sensor characteristics of the sensor body hardly fluctuate can be further exhibited.

The sensor according to the fourth aspect has the effect of the sensor according to any one of the second to third aspects, and is formed between the case and the cover near the engaging portion of the cover. Since the gap is locally reduced, the displacement due to the engagement can be minimized.

In the sensor according to the fifth aspect, in addition to the effect of the sensor according to the first aspect, the circuit board is restricted by the restricting portion provided on the cover from being displaced toward the opening of the case. Even if the fixing is loosened, it will not be separated.

In the sensor according to the sixth aspect, in addition to the effect of the sensor according to the fifth aspect, even if the circuit board is distorted, the displacement toward the opening of the case is restricted by the restricting portion provided on the cover. Since the distortion of the circuit board is detected by the detection circuit provided on the circuit board, it is possible to detect that the circuit board is distorted before the circuit board is damaged by the distortion.

In the sensor according to the seventh aspect, in addition to the effect of the sensor according to the first aspect, when the circuit board is displaced toward the opening of the case, the pressing portion provided on the cover is provided.
Pressing on the circuit components mounted on the circuit board,
Since the normal operation of the circuit component is hindered, the displacement of the circuit board toward the opening of the case can be detected.

In the sensor according to the eighth aspect, in addition to the effect of the sensor according to any one of the first to seventh aspects, since the sensor body is a semiconductor sensor chip, the detection accuracy can be increased. .

[Brief description of the drawings]

FIG. 1 is a side sectional view of a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is a perspective view of the same case as seen from the back side.

FIG. 4 is a front sectional view of the same.

FIG. 5 is a plan view of the same.

FIG. 6 is a perspective view showing an assembling procedure of the same.

FIG. 7 is a front sectional view of a second embodiment of the present invention.

FIG. 8 is a perspective view of a case according to a third embodiment of the present invention as viewed from the back side.

FIG. 9 is a side sectional view of the same.

FIG. 10 is a side sectional view of the same.

FIG. 11 is a perspective view of a case according to a fourth embodiment of the present invention as viewed from the back side.

FIG. 12 is a front sectional view of the same.

FIG. 13 is a side sectional view of the same.

FIG. 14 is a sectional view of a conventional example.

[Explanation of symbols]

 Reference Signs List 1 semiconductor sensor chip (sensor main body) 8 sensor element 10 circuit board 11 electronic component (circuit component) 13 case 13f engaged portion 16 cover 16c engaging portion 16d attaching portion 16e limiting portion 16f pressing portion 20 gap

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F055 AA39 BB20 CC02 DD05 EE14 FF23 FF43 GG25 4M112 AA01 BA01 CA12 CA15 EA03 GA01 GA03

Claims (8)

[Claims] 1. A sensor comprising: a box-shaped case having an opening and internally fixing a sensor main body so as to be positioned on the opening side; and a cover for closing the opening of the case, wherein the case has rigidity. And an engaged portion provided with an engaging portion provided on the cover so as to have elasticity. 2. The sensor according to claim 1, wherein the cover has a mounting portion for external mounting, and the mounting portion is substantially equal to the engaging portion. 3. The sensor according to claim 1, wherein the cover has a mounting portion for external mounting, and a gap formed between the case and the cover is locally increased near the mounting portion. . 4. The sensor according to claim 2, wherein a gap formed between the case and the cover is locally reduced near the engagement portion of the cover. 5. A circuit board for processing signals from the sensor main body and a sensor element for supporting the sensor main body are fixed inside the case. The cover is attached to the outside, and the circuit board is mounted on the case. 2. The sensor according to claim 1, further comprising a restricting portion that restricts displacement toward an opening of the case, on a side of the opening of the case. 3. 6. The sensor according to claim 5, wherein the circuit board is provided with a detection circuit for detecting a distortion of the circuit board itself. 7. A circuit board for processing a signal from the sensor main body and a sensor element for supporting the sensor main body are fixed inside the case, and the cover is attached to the outside and the cover is mounted on the circuit board. The sensor according to claim 1, further comprising a pressing portion on the opening side of the case, the pressing portion pressing the circuit component when the mounted circuit component is displaced toward the opening of the case. 8. The sensor according to claim 1, wherein the sensor body is a semiconductor sensor chip.