JP2019027865A - Sensor device - Google Patents

Abstract

To suppress measurement errors by sealing the diaphragm of a physical quantity measurement sensor and also to suppress measurement errors caused by the difference in the height between the surface and the sides of the physical quantity measurement sensor.SOLUTION: In the sensor device according to the present invention, an air flow rate sensor is arranged on a pattern (step) formed on a print substrate to be used as a communication port, and the height of the surface and the sides of the air flow rate sensor are made almost the same by provision of a plate at the sides of the sensor.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sensor device that measures a physical quantity such as an air flow rate and a pressure, and more particularly to a multifunction sensor that measures an intake air quantity, pressure, temperature, humidity, and the like of an internal combustion engine.

  The physical quantity of the air flow rate is widely used as an important control parameter in various devices, and a sensor for measuring these physical quantities is one of important components that influence the performance of the equipment. For example, a vehicle equipped with an internal combustion engine has a very high demand for fuel saving and exhaust gas purification.

  The air flow rate sensor has a diaphragm structure, and when this diaphragm is sealed, the diaphragm is deformed due to a temperature change, and an error occurs in the air flow rate characteristic.

  As means for solving the above problems, for example, there is one disclosed in JP-A-6-50783 (Patent Document 1). Patent Document 1 describes providing a communication port for preventing sealing of the back space of the diaphragm.

JP-A-6-50783

  In recent years, in order to further improve fuel economy and exhaust gas purification, a multifunctional flow measurement device that measures not only air flow but also physical quantities of pressure and humidity with high accuracy has been required.

  When mounting the above sensors for measuring pressure, humidity, and temperature, it is convenient to use a printed circuit board that can be mounted by soldering because it can be easily mounted. In addition, even a single-function flow measurement device that does not measure pressure and humidity can be improved in mass production efficiency by sharing a substrate with a multi-function flow measurement device, so that it is required to be mounted on a printed circuit board. ing.

  The medium to be measured contains water, dust, and the like, and in order to prevent the penetration of water and the like and prevent the through hole from being blocked, a certain degree of accuracy is required for the size of the through hole. . The printed circuit board is difficult to process, and it is difficult to form through holes with high precision by machining such as cutting. In addition, since cutting generates chips, the yield is also deteriorated.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a physical quantity measuring device capable of easily forming a communication hole even when a physical measuring device having a diaphragm is mounted on a printed board. .

  In order to achieve the above-described object, the physical quantity detection device of the present invention has a physical quantity detection element having a diaphragm mounted on a pattern formed on the surface layer of a printed circuit board. A communication port that communicates is formed.

  According to the present invention, it is possible to easily form the communication ports necessary for disposing the flow rate sensor on the printed circuit board and the heights of the air flow rate sensor surface and the surrounding area.

It is the top view and sectional view of a printed circuit board in the 1st example concerning this application. It is the top view and sectional view of a printed circuit board in the 1st example concerning this application. It is the top view and sectional view of a printed circuit board in the 1st example concerning this application. It is the top view and sectional view of a printed circuit board in the 2nd example concerning this application. It is the top view and sectional view of a printed circuit board in the 4th example concerning this application. It is the top view and sectional view of a printed circuit board in the 4th example concerning this application. It is the top view and sectional view of a printed circuit board in the 3rd example concerning this application. It is the top view and sectional view of a printed circuit board in the 3rd example concerning this application.

  Embodiments of the present invention will be described below with reference to the drawings.

[Example 1]
First, a first embodiment of the sensor device will be described with reference to FIGS. Each figure shows a plan view and a cross-sectional view. As shown in FIG. 1, a pattern 2 made of copper having a thickness of about 50 μm is provided in a region of the printed circuit board 1 where the air flow sensor 6 is disposed. Thereafter, a resist 3 is applied for the purpose of protecting the pattern 2. At this time, a step 4 due to the thickness of the pattern 2 is formed.

  As shown in FIG. 2, the back surface of the air flow sensor 6 and the resist 3 are bonded with an adhesive tape 5. The air flow sensor 6 is disposed on the pattern 2. A communication port 7 for eliminating a pressure difference between the inside and the outside of the diaphragm 12 is formed between the printed circuit board 1 and the air flow sensor 6.

  After that, as shown in FIG. 3, the air flow sensor 6 and wiring (not shown) on the printed circuit board 1 are connected by wire bonding 8 in order to output an electric signal of the air flow sensor 6 to the outside. The wire bonding 8 is protected by the resin 10.

  In this embodiment, a physical quantity detection element having a diaphragm is mounted on a pattern formed on the surface layer of a printed circuit board, and a communication port that communicates the inside and outside of the diaphragm is formed using a step formed by the pattern. The dimension of the communication port 7 is determined by the step 4, and the shape of the step 4 is determined by the copper film pattern 2 formed on the surface layer of the printed circuit board 1. Since the copper film can be accurately shaped, the communication port 7 can be provided with higher accuracy than when the printed circuit board is processed. Moreover, since the copper film pattern 2 can be formed simultaneously with the formation of the wiring, it can be implemented without any additional process. Further, since machining such as cutting is not required for the printed circuit board and the cutting waste and the cut surface are not formed on the rear surface of the diaphragm, it contributes to yield improvement.

  A further example of the first embodiment will be described.

  As a first good example, as shown in FIG. 1, the pattern 2 on the printed circuit board 1 does not have an opening (step 4) on the upstream side of the air, and the tip in the direction perpendicular to the downstream side and the flow direction (on the resin 10 side). (Not). By such a pattern arrangement, it is possible to suppress the ingress of water coming from upstream into the diaphragm 12.

  As a second good example, when the air flow rate sensor 6 is wire-bonded, if there is an opening in the wire bonding base, the air flow rate sensor 6 bends, so that wire bonding becomes difficult. Therefore, it is preferable to use a pattern in which no opening is provided in the lower region of the pad portion where wire bonding is performed.

  As a third good example, the pattern 2 made of copper is preferably placed on the GND, is floating, or has the same potential. This is because a potential difference occurs between the patterns 2 and copper may corrode when salt water or the like enters. In the third good example, there may be no resist 3 for protecting the pattern 2 formed of copper. That is, the step 4 may be formed by the copper pattern 2.

  In the present embodiment, the air flow sensor 6 has been described as an example of the physical quantity sensor, but the present invention is not limited to the flow sensor, and other physical quantity sensors (for example, a thermal humidity sensor) having the diaphragm 12 are used. Is also applicable.

  Moreover, although copper was shown as an example of the material which forms the pattern 2, the same effect can be achieved with another metal material.

[Example 2]
A second embodiment of the present invention will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.

  In this embodiment, a U-shaped (or U-shaped) plate 9 is provided on the printed circuit board 1 with an adhesive around the air flow sensor 6. The resin 10 covering the wire bonding portion is also covered with a part of the plate 9.

  As shown in the AA sectional view of FIG. 4, the surface of the plate 9 and the surface of the flow sensor 6 are formed so that the height from the printed board 1 is substantially equal. That is, since the surface of the plate 9 and the surface of the flow sensor 6 are formed substantially horizontally in the flow direction, the occurrence of turbulent flow can be suppressed, so that errors in flow measurement can be suppressed.

  According to the present embodiment, since the height around the flow sensor 6 can be made substantially equal without processing the printed circuit board, even when the printed circuit board is used, an error in flow measurement can be easily suppressed. It is possible.

  If the plate 9 is formed of a resin material, it is advantageous in terms of corrosion resistance, workability, and weight reduction.

  If the plate 9 is formed of a metal material, it is advantageous from the viewpoint of anti-staining properties since noise resistance and charge neutralization of charged particles can be performed.

  An advantage of the U-shaped plate 9 is that the printed circuit board 1, the air flow sensor 6, and the plate 9 can be easily bonded to each other by the resin 10. In particular, in order to suppress measurement errors on the forward flow side and the reverse flow side, when plates are provided on the forward flow side and the reverse flow side, the forward flow side and the reverse flow side are not mounted separately, but the forward flow side and the reverse flow side are integrated. By making the U-shaped plate into the shape, a member for adjusting the height of the forward flow side and the reverse flow side can be mounted at the same time, so that the manufacturing process can be simplified.

  As a further good example, the narrower gap 14 between the air flow sensor 6 and the plate 9 shown in FIG. According to the experiments conducted by the present authors, water does not enter when the thickness is 100 μm or less, and therefore the gap 14 is preferably 100 μm or less.

  In the present embodiment, the air flow sensor 6 is first disposed on the printed circuit board 1 and then the plate 9 is disposed. However, the plate 9 may be disposed on the printed circuit board 1 and then the air flow sensor 6 may be disposed. I do not care.

[Example 3]
A third embodiment of the present invention will be described. Note that the description of the same configuration as in the first or second embodiment is omitted.

  In the first embodiment, the pattern 2 made of copper is arranged on the printed circuit board 1, but the resist 3 is patterned by a film forming process. As shown in FIG. 7, a pattern 15 is formed by a resist, and a resist 3 is further formed thereon to form a step 4. As shown in FIG. 8, since the communication port 7 can be formed even with the pattern 15 of the resist 3, there is no deformation of the diaphragm 12 due to temperature change, and no flow measurement error occurs. Moreover, there is no worry of corrosion of the copper pattern 2.

[Example 4]
Embodiment 4 of the present invention will be described. Note that the description of the same configuration as that of the second embodiment is omitted.

  In this embodiment, as shown in FIG. 5, unevenness 11 is provided on the surface where the printed circuit board 1 and the plate 9 are bonded to each other, and is fixed with an adhesive. Although the unevenness is expressed as one place on each side, there may be a plurality of places.

  This is preferable because the positioning of the plate 9 on the printed circuit board 1 is facilitated. The convex of the printed circuit board 1 can be formed by a copper pattern 2 or a pattern 2 of a resist 3, and the concave of the plate can be achieved by devising a mold.

  In addition, since the generation | occurrence | production of a turbulent flow can be further suppressed if corner | angular part removal 13 is carried out as shown in FIG. 6, you may remove the corner | angular part of a plate like FIG.

DESCRIPTION OF SYMBOLS 1 ... Printed circuit board 2 ... Pattern 3 ... Resist 4 ... Level difference 5 ... Simple adhesive tape 6 ... Air flow sensor 7 ... Communication port 8 ... Wire bonding 10 ... Resin 11 ... Unevenness 12 ... Diaphragm 13 ... Corner | angular part removal 14 ... Gap
15 ... pattern

Claims (12)

  A physical quantity detection device in which a physical quantity detection element having a diaphragm is mounted on a pattern formed on a surface layer of a printed circuit board, and a communication port that communicates the inside and outside of the diaphragm is formed using a step formed by the pattern.   The physical quantity detection device according to claim 1, wherein the pattern has no opening on the upstream side of the air and has an opening on the downstream side and in a direction perpendicular to the flow direction.   The physical quantity detection device according to claim 1, wherein the pattern is formed using copper.   The physical quantity detection device according to claim 1, wherein the pattern is formed using a resist.   The physical quantity detection device according to claim 1, wherein the pattern is made of copper and formed thereon using a resist.   6. The physical quantity detection device according to claim 3, wherein the pattern is not electrically connected anywhere.   A resin plate member is mounted on the surface layer of the printed circuit board, and the resin plate member is positioned on the upstream side of the physical quantity detection element having at least a part of the diaphragm, and the surface of the resin plate member and the physical quantity detection element The physical quantity detection device according to claim 1, wherein the surface has substantially the same height in a cross section in the flow direction. The resin plate member is a U-shaped resin plate,
8. The physical quantity detection device according to claim 7, wherein the physical quantity detection device is mounted on the printed circuit board so that a physical quantity detection element having the diaphragm is mounted in an opening.   Between the physical quantity detection element having the diaphragm and the printed board, there is a simple adhesive member that surrounds the four sides of the mounting surface, and the physical quantity detection element and the printed board are electrically connected by a metal wire, The physical quantity detection device according to claim 1, wherein the metal wire, a part of the physical quantity detection element, and a part of the resin member are covered with resin.   10. The physical quantity detection device according to claim 1, wherein the physical quantity detection element having the diaphragm is a flow rate detection element.   10. The physical quantity detection device according to claim 1, wherein the physical quantity detection element having the diaphragm is a humidity detection element. The back surface of the resin plate member and the printed board surface are provided with irregularities so that the resin plate and the printed board fit together,
9. The physical quantity detection device according to claim 7, wherein the physical quantity detection device is mounted on the printed circuit board so that a physical quantity detection element having the diaphragm is mounted in an opening.

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