JP3103526B2 - Pressure sensor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor for detecting a pressure of a fluid, and more particularly to a pressure sensor for receiving a fluid pressure by a semiconductor element and electrically detecting the pressure, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a semiconductor type pressure sensor has been provided as a small-sized pressure sensor capable of accurately measuring the pressure of gas. As shown in a vertical sectional view of FIG. 6, a conventional semiconductor pressure sensor includes an outer frame 1 of a pressure sensor and a gas inlet 2 formed integrally with the outer frame 1 and having a thin tip 3.
And a sensor case 6 containing a silicon substrate 4 is housed in the outer frame 1. A silicon film 5 having a thickness of several microns is formed on the silicon substrate 4 by etching, and a semiconductor resistor whose resistance value changes due to mechanical strain is formed on the silicon film 5. The sensor case 6 is provided with a printed circuit board 8 on which an air introduction portion 7 is formed and on which an electric circuit such as an amplifier circuit is formed. Input / output terminals 9 are provided on the printed circuit board 8, housed in the outer frame 1, and molded with a synthetic resin 10. The sensor case 6 is bonded to the inside of the outer frame 1 with an adhesive 11, and a gel 12 is provided on the silicon film 5 so as not to directly contact dust or moisture contained in the gas.
Is coated. The electric circuit formed on the printed circuit board 8 has a function of amplifying the change in the resistance value. The input / output terminals 9 are a power supply terminal for supplying power to an electric circuit on the printed circuit board 8 and a resistor on the silicon film 5, an output terminal for amplifying and outputting a change in resistance value, and a ground terminal. .

In the measurement method of this semiconductor type pressure sensor, first, when a gas pressure is applied from the gas introduction unit 2, a mechanical difference is caused between the atmospheric pressure and the gas pressure applied from the air introduction unit 7 to the silicon film 5. Causes distortion. This distortion is proportional to the pressure difference between the gas pressure and the atmospheric pressure. When the silicon film 5 is distorted, the value of the resistance formed on the silicon film 5 changes in proportion to the magnitude of the distortion. By detecting the change in the resistance value, amplifying and outputting the amplified value, the differential pressure between the gas pressure and the atmospheric pressure can be measured.

[0004]

In the case of the above-mentioned prior art, the joint between the sensor case 6 and the outer frame 1 is formed by bonding the flat joint end face of the sensor case 6 to the flat bottom surface of the outer frame 1. Therefore, the adhesive strength is low, the airtightness is not high, and there is a problem in terms of safety in measuring the pressure of toxic gas, flammable gas, and the like. In addition, since flat surfaces are bonded to each other, there is no reference for positioning, and there is a problem that it is difficult to accurately bond the position of the sensor case to a predetermined position. Furthermore, when the sensor case is embedded in the resin, it is necessary to prevent the filled resin from entering the inside. However, if there is a gap in the bonding portion, the filled resin will enter the gap, and the silicon substrate 4 To the sensor and harm the characteristics of the sensor.

The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a pressure sensor having high joining strength between a sensor case and a housing member thereof and having high airtightness at a joining portion. And

[0006]

According to the present invention, there is provided a semiconductor pressure sensor element, a sensor case accommodating and holding the pressure sensor element, and a pressure introducing portion for introducing a measured pressure. A housing member attached to and joined to the sensor case, a ridge provided over the entire periphery of one joint portion between the sensor case and the accommodation member, and the projection formed over the other entire periphery of the joint portion between the sensor case and the accommodation member. A concave portion in which the ridge is fitted, a surface mount type lead frame is insert-molded integrally with the sensor case, and the lead frame extends in a projecting direction of a pressure introducing portion formed in the sensor case, A pressure sensor in which the lead frame is surface-mounted on a printed circuit board, and the sensor case and the printed circuit board are embedded in resin in the housing member. .

Further, a side wall surrounding the sensor case is formed outside the ridges and the recesses, and the side wall is covered with the resin. Further, the outer shapes of the above-mentioned ridges and recesses are formed in a V-shape.

According to the present invention, there is provided a semiconductor pressure sensor element, a sensor case accommodating and holding the pressure sensor element, and a pressure introducing portion for introducing a pressure to be measured. The convex member formed over the entire periphery of one joint portion between the sensor case and the housing member and the convex line formed over the other periphery of the joint portion between the sensor case and the housing member are fitted. And a surface mount type lead frame is insert-molded together with the sensor case, and after joining the ridge and the concave portion over the entire circumference, the sensor case lead frame is surface-mounted on a printed circuit board, Manufacturing the pressure sensor, wherein the sensor case and a printed circuit board provided in the sensor case are embedded in a resin in the housing member. It is the law.

In the pressure sensor according to the present invention, the sensor case and the housing member are bonded by fitting the ridge and the recess formed at the joint thereof, so that the airtightness and strength of the joint are extremely high. It is high and the alignment is easy due to the unevenness. Further, a lead frame is integrally formed with the sensor case by insert molding, so that the sensor frame is easily and reliably attached to the circuit board.

[0010]

Embodiments of the present invention will be described with reference to the drawings. 1 to 3 show an embodiment of the present invention.
A semiconductor sensor element 15 is provided in a sensor case 17. The sensor element 15 is adhered to the glass base 14. The glass base 14 is fixed in the mounting recess 18 of the sensor case 17 by an adhesive 16 made of a silicon resin. Sensor case 1
Reference numeral 7 is made of a heat-resistant resin such as PPS resin, and the lead frame 20 is provided by insert molding. One end of lead frame 20 and sensor element 1
5, a gold wire 22 is bonded. The sensor case 17 has an atmospheric pressure introducing cylinder 24 as a pressure introducing section.
Are formed integrally, and in the mounting concave portion 18 on the surface side of the sensor element 15 on the opposite side to the atmospheric pressure introducing cylinder 24,
Potting agent 2 such as polyurethane gel or silicone gel
6 are filled, and the sensor element 15 and the gold wire 22 are embedded.

The lead case 2 is provided in the sensor case 17.
The printed circuit board 28 is attached via the reference numeral 0, and the terminal 30 is fixed to the printed circuit board 28. The sensor case 17 is joined to a central portion of a housing 32 which is a housing member formed of PBT resin or the like by an epoxy adhesive 34. In this joint portion, a V-shaped concave groove 36 is formed over the entire periphery of the end surface on the sensor case 17 side, and a convex ridge 40 is formed on the inner bottom surface 38 of the housing 32. 36. Outside the ridge 40 of the housing 32, a side wall 50 is formed so as to surround a side edge of the sensor case 17, and a corner of the end face of the sensor case 17 is joined by an adhesive 34.

The sensor case 17 is provided with a potting agent 26.
The surface side of the sensor element 15 covered with
Is mounted facing the pressure introducing cylinder 46 side which is a pressure introducing portion of the above. In the housing 32, the sensor case 17
Are filled with a silicone resin filler 42 and a soft epoxy resin filler 44 further filled thereon,
The atmospheric pressure introducing cylinder 24 and the terminal 30 are formed in a protruding state.

According to the pressure sensor of this embodiment, the connection between the sensor case 17 and the housing 32 is
Are joined via the adhesive 34 by fitting with the concave groove 36, so that the joining strength is high, the alignment at the time of assembly is easy, and the attachment is easy.

The pressure sensor of the present invention is not limited to the above-described embodiment, and the ridge 40 formed on the housing 32 may be fitted and fixed to the concave groove 36 of the sensor element by ultrasonic welding. At this time, the shapes of the concave groove 36 and the ridge 40 are as shown in FIG.
As shown in FIG. 5A, the tip of the ridge 40 may be melted and welded to the U-shaped groove 36 by ultrasonic vibration.
As shown in (B), the ridge 40 may be ultrasonically welded to the concave portion 36 formed by the notch. In the case of ultrasonic welding, it is preferable to form a through hole in the printed circuit board 28 in order to bring the ultrasonic element to be welded into contact with the sensor case 17.

Accordingly, even when the sensor case 17 and the housing 32 cannot be bonded to each other by the adhesive, the resin is reliably melted and fixed, so that the mounting strength can be extremely increased. In addition, since no adhesive is used, the workability of the mounting work is good and the handleability is also good.

The recesses and ridges of the pressure sensor of the present invention may be formed on either the sensor case or the housing.
Or a W-shaped portion, and a convex portion formed of an L-shaped corner portion,
It may be one that engages with a concave portion consisting of a corner of a mold.

[0017]

According to the pressure sensor of the present invention, the sensor case is easily adhered to the housing member, the mounting strength is high, the medium to be measured does not flow out of the sensor, and the safety and reliability are high. Can be something. Further, the attachment can be easily and accurately performed by matching the concave and convex portions. Furthermore, a lead frame is insert-molded on the sensor case, making it easy to attach to the board,
This facilitates downsizing of the apparatus and cost reduction. In addition, the board is embedded in the resin, and the connection of the lead frame mounted on the surface is protected and secured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a pressure sensor according to a first embodiment of the present invention.

FIG. 2 is a partially broken front view of a sensor case of the pressure sensor according to the first embodiment.

FIG. 3 is a partially broken bottom view of a sensor case of the pressure sensor according to the first embodiment.

FIG. 4 is a plan view of the easing of the pressure sensor of the first embodiment.

FIG. 5 is a partial longitudinal sectional view showing a joint between a sensor case and a housing of a pressure sensor according to another embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a conventional technique of the present invention.

[Explanation of symbols]

 15 Sensor element 17 Sensor case 32 Housing 36 Groove 40 Convex ridge

Continuation of the front page (56) References JP-A-2-248829 (JP, A) JP-A-4-155970 (JP, A) JP-A-63-238534 (JP, A) JP-A-61-253437 (JP) , A) Japanese Utility Model Showa 57-6042 (JP, U) Japanese Utility Model Showa 60-166163 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01L 9/04

Claims (4)

(57) [Claims] An accommodating member having a semiconductor pressure sensor element, a sensor case accommodating and holding the pressure sensor element, and a pressure introducing portion for introducing a measured pressure, wherein the sensor case is mounted and joined inside. A ridge provided over the entire circumference of one of the joining portions of the sensor case and the housing member, and a concave portion formed over the other circumference of the joining portion of the sensor case and the housing member and fitted with the ridge. A surface mount type lead frame is integrally insert-molded with the sensor case, the lead frame extends in a direction in which a pressure introducing portion formed in the sensor case protrudes, and the lead frame is mounted on a printed circuit board. The sensor case and the printed circuit board are mounted in a resin in the housing member, and the resin is located outside the ridges and the recesses. A pressure sensor characterized by preventing entry of fat. 2. The pressure sensor according to claim 1, wherein a side wall portion surrounding the sensor case is formed outside the ridge and the concave portion, and the resin is filled so as to cover the side wall portion. 3. The pressure sensor according to claim 1, wherein the outer shape of the ridge and the recess is formed in a V-shape. 4. A housing member having a semiconductor pressure sensor element, a sensor case housing and holding the pressure sensor element, and a pressure introducing part for introducing a measured pressure, wherein the sensor case is mounted and joined inside. A ridge provided over the entire circumference of one of the joining portions of the sensor case and the housing member, and a concave portion formed over the other circumference of the joining portion of the sensor case and the housing member and fitted with the ridge. After the surface mount type lead frame is insert-molded together with the sensor case, and the ridge and the concave portion are joined over the entire circumference, the lead frame of the sensor case is surface-mounted on a printed circuit board, and the sensor case is provided. And a printed circuit board provided in the sensor case is embedded in a resin in the housing member.