JP2011007532A - Sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress short-circuiting between electrodes of chip capacitors when using conductive adhesives, such as silver paste, for adhering the chip capacitors.SOLUTION: A molding material F is interposed between terminal boards where both the electrodes of a chip capacitor 28 are stuck, and two grooves D are provided on a surface of the molding material F. The excess of silver paste 29 for adhering the electrodes of the chip capacitor 28 flows into different grooves D for the respective electrodes, thus reducing a risk of contacting of each silver paste 29 for adhering both the electrodes and hence suppressing short-circuiting between the electrodes of the chip capacitor 28.

Description

  The present invention relates to a sensor device.

  Conventionally, an input terminal board, an output terminal board, and a ground terminal board are directly connected to a sensor unit that detects a physical quantity and generates a corresponding electrical signal, and is bridged between the input terminal board and the ground terminal board. There is a sensor device in which a chip capacitor is surface-mounted in a form that is surface-mounted and bridged between an output terminal plate and a ground terminal plate (see Patent Document 1). In this conventional example, high frequency noise included in the input signal and output signal is emitted to the ground terminal plate through the chip capacitor, and the high frequency noise included in each signal is reduced. Moreover, in this conventional example, since each terminal board is directly connected to the sensor part, it is not necessary to use a printed wiring board, and a sensor apparatus can be comprised at low cost.

  In this conventional example, the electrode of the chip capacitor is fixed to the terminal board using solder. Such surface mounting component soldering methods include reflow soldering and manual soldering, but reflow soldering is generally used for industrial mass production soldering. However, in reflow soldering, the entire sensor device must be placed in a reflow furnace and placed in a high temperature environment, which may cause a problem with a chip capacitor or change the characteristics of the sensor unit.

  In order to solve this problem, it is conceivable to bond the chip capacitor using a conductive adhesive such as silver paste instead of solder. However, when a conductive adhesive such as silver paste is used, if the amount of this conductive adhesive is excessive, each conductive adhesive that bonds both electrodes of the chip capacitor spreads and contacts each other, There is a risk of short-circuiting between the electrodes of the capacitor.

  As a means for solving this problem, Patent Document 2 describes a circuit board in which one groove is formed on the surface of a circuit board on which an electronic component is arranged in a circuit board on which the electronic component is surface-mounted. In this conventional example, both ends of the electronic component bonded by the silver paste are arranged so as to straddle this groove. Therefore, since excess silver paste flows into this groove | channel, it can suppress that both ends of an electronic component short-circuit.

JP 2008-241456 A JP-A-10-75021

  However, in the above conventional example, each silver paste that adheres both ends of the electronic component flows into the same groove, so that the silver paste that has flowed into the groove is brought into contact with each other, and both ends of the electronic component are contacted. Could short circuit.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a sensor device that suppresses short-circuiting between electrodes of a chip capacitor.

  In order to achieve the above-mentioned object, the invention of claim 1 has a sensor element for detecting a physical quantity, a sensor section for generating an electrical signal corresponding to the detected physical quantity, and an input connected to the sensor section. A terminal plate, an output terminal plate, a ground terminal plate, an insulator interposed in a gap between these terminal plates, and straddling the insulator, between the input terminal plate or the output terminal plate and the ground terminal plate A chip capacitor to be installed; a conductive adhesive for fixing both electrodes of the chip capacitor to the terminal plates; a case in which a terminal hole is formed to house the sensor portion and expose one end of each terminal plate; And two non-intersecting grooves for allowing the conductive adhesive to flow into the surface of the insulator sandwiched between the two electrodes of the chip capacitor intersect with the bridging direction of the chip capacitor. Characterized in that formed along the direction.

  In the present invention, an insulator is interposed between the terminal plates to which both electrodes of the chip capacitor are fixed, and two grooves are provided on the surface of the interposed insulator. Therefore, the surplus of the conductive adhesive that bonds the electrodes of the chip capacitor flows into different grooves for each electrode. Therefore, the possibility that the conductive adhesives come into contact with each other is reduced, and a short circuit between the electrodes of the chip capacitor can be suppressed.

  The present invention can provide a sensor device that suppresses a short circuit between electrodes of a chip capacitor.

It is sectional drawing of the chip capacitor | condenser 28 vicinity which concerns on embodiment of this invention. It is a mimetic diagram of sensor block 2 concerning an embodiment of the present invention. It is sectional drawing of embodiment of this invention. It is a top view of the terminals 23 to 26, the package 3, and the first case 51 according to the embodiment of the present invention. It is a mimetic diagram of sensor block 2 before separating from lead frame A concerning an embodiment of the present invention.

  Hereinafter, embodiments in which the present invention is applied to a pressure sensor device for detecting pressure will be described with reference to the drawings. In the following description, the vertical and horizontal directions are defined in FIG. 3, and FIG. 3 is a cross-sectional view taken along the line XX of FIG.

  The sensor device 1 of this embodiment is for measuring the pressure of a fluid, and includes a sensor block 2, a package 3, oil 4, and a housing 5. The sensor device 1 can be applied to a water level sensor that is attached to a flow path of water in a water heater of a bathtub and detects the water level of the bathtub by the pressure in the flow path, for example.

  As shown in FIG. 2, the sensor block 2 includes a pressure sensor chip 21, an integrated circuit chip 22, an input terminal plate 23, a ground terminal plate 24, an output terminal plate 25, and a dummy terminal plate 26. Housed in the package 3, the left end portions of the terminal plates 23 to 25 and the left end portion or right end portion of the five dummy terminal plates 26 are exposed from the left and right side wall portions of the package 3. Each chip 21, 22 and the terminal plates 23 to 26 are electrically connected through bonding wires 27.

  The pressure sensor chip 21 includes a diaphragm and a plurality of piezoresistive elements (not shown), and a recess 21a is formed by processing a silicon substrate. The integrated circuit chip 22 processes a detection value detected from the pressure sensor chip 21. Further, the piezoresistive element of the pressure sensor chip 21 is easily affected by the ambient temperature outside the sensor device 1 and may not be able to correctly detect a change in resistance value due to the deflection of the diaphragm. The ambient temperature is detected and temperature correction is also performed on the detected value.

  Recesses 23a to 26a are formed at the left and right ends of the terminal plates 23 to 26 exposed from the package 3, respectively, and the left end portions of the three terminal plates 23 to 25 are each provided with a width in the short direction. Terminal pieces 23b to 25b that are smaller than the width in the lateral direction of 23 to 25 are extended. And the molding material F which is the synthetic resin material which has insulation is filled in the clearance gap between each terminal boards 23-26 inside the package 3, and it is integral with the lower surface of the main-body part 3a of the package 3 mentioned later. . Inside the package 3, the chip capacitor 28 is surface-mounted so as to be bridged between the input terminal plate 23 and the ground terminal plate 24. Similarly, the chip capacitor 28 is bridged between the output terminal plate 25 and the ground terminal plate 24. A chip capacitor 28 is surface mounted. Each electrode of the chip capacitor 28 is bonded to the terminal plates 23 to 25 by a conductive adhesive such as a silver paste 29. Here, on the surface of the molding material F sandwiched between both electrodes of the chip capacitor 28, as shown in FIG. 1, two grooves D that do not intersect with each other are formed along the terminal plates 23 to 25. Yes.

  The package 3 has a main body 3a formed in a flat and substantially rectangular shape whose one surface (upper surface in FIG. 3) is opened by the molding material F, and an introduction pipe 3b that protrudes in a cylindrical shape from the outer surface of the lower end of the main body 3a. It consists of. The pressure sensor chip 21 of the sensor block 2 is fixed to the inner bottom surface of the main body 3a with the recess 21a facing downward, and the position facing the pressure sensor chip 21 passes through the axis of the introduction tube 3b to the outside. A pressure introducing hole 3c that penetrates straight is formed. The pressure introducing hole 3c and the recess 21a communicate with each other, and the hole 4 is filled with oil 4 for transmitting pressure from the fluid to the pressure sensor chip 21. The oil 4 is non-corrosive, and even if the fluid is corrosive, the oil 4 is interposed between the fluid and the pressure sensor chip 21 to prevent the pressure sensor chip 21 from being corroded. be able to.

  The sensor block 2 housed in the package 3 is sealed with a sealing material 31 made of a coating resin and filled from the opening of the package 3, and the upper surface of the package 3 has a rectangular plate shape so as to close the opening. The cover 32 is attached.

  As shown in FIG. 3, the housing 5 includes a first case 51 and a second case 52 that are formed in a flat rectangular box shape that opens on one surface, and is joined by attaching the opening surfaces to each other. Become. A port portion 51 a that protrudes downward in a cylindrical shape is formed at the lower end portion of the first case 51. A step portion 51b that is recessed downward is formed on the inner bottom surface 51h of the first case 51, and a hole portion 51c is formed in the bottom surface of the step portion 51b. Then, the introduction pipe 3b of the package 3 is inserted into the hole 51c, and the lower end of the main body 3a is fitted into the step 51b. At this time, the left and right ends of the inner bottom surface 51h of the first case 51 have projections 51d at positions facing the recesses 23a to 26a of the respective terminal plates 23 to 26, as shown in FIGS. Is projected, and the protrusion 51d is fitted into the recesses 23a to 26a and fixed by caulking.

  Moreover, the terminal pieces 23b-25b of the terminal plates 23-25 are derived | led-out outside through the outlet 5b formed in the left wall part 5a of the housing 5, as shown in FIG. A male connector 5c is formed on the periphery of the left wall portion 5a of the housing 5 so as to protrude in a substantially square shape so as to surround the tip portions of the terminal pieces 23b to 25b when viewed from the left direction. Therefore, the detected value detected by the pressure sensor chip 21 can be taken out from the sensor device 1 through a female connector (not shown) that is detachably connected to the connector 5c.

  On the inner bottom surface of the hole 51c, as shown in FIG. 3, a through hole 51e having an inner diameter substantially the same as the inner diameter of the pressure introduction hole 3c is provided downward through the port 51a at a position facing the pressure introduction hole 3c of the package 3. It is penetrated toward. Further, as shown in FIG. 3, an O-ring 53 formed in an annular shape from an elastic material and having an inner diameter substantially equal to the outer diameter of the introduction tube 3b is fitted to the inner peripheral surface of the hole 51c. The O-ring 53 is restricted from moving upward by a washer 54 disposed thereon. The introduction pipe 3b is inserted into the hole 51c and inserted through the O-ring 53, whereby the gap between the package 3 and the housing 5 is sealed.

  When a fluid such as water flows into the through hole 51e from the opening 51f on the lower surface of the port 51a, the diaphragm of the pressure sensor chip 21 is bent through the oil 4 and the piezoresistive element is distorted. And the resistance value of a piezoresistive element changes with this distortion, The pressure of the fluid is measured by taking out the detected value detected according to the change.

  Next, a method for manufacturing the sensor block 2 will be described with reference to FIG.

  First, a thin metal plate such as a hoop material is punched to form a lead frame A including the terminal plates 23 to 26. Next, the package 3 composed of the main body 3a and the introduction tube 3b is integrally molded from the molding material F. At this time, the molding material F that fills the gaps between the terminal plates 23 to 26 is molded integrally with the lower surface of the main body 3a. Subsequently, two grooves D are formed at a position where the chip capacitor 28 is arranged on the surface of the molding material F by a technique such as laser processing. This groove | channel D is formed so that it may not mutually cross | intersect along each terminal board 23-25. Then, two chip capacitors 28 are respectively arranged so as to be bridged by the input terminal plate 23 and the ground terminal plate 24, the output terminal plate 25 and the ground terminal plate 24, and straddle the groove D, respectively. To each terminal board 23-25. Here, when heating is necessary for solidification of the silver paste 29, the sensor block 2 is heated using an appropriate heating means such as a reflow furnace. Further, the pressure sensor chip 21 and the integrated circuit chip 22 are fixed on the molding material F inside the package 3 with an adhesive or the like. Then, the terminal plates 23 to 26 are electrically connected to the pressure sensor chip 21 and the integrated circuit chip 22 by bonding wires 27. Finally, each of the terminal plates 23 to 26 is separated from the outer frame of the lead frame A, and the sensor block 2 is formed.

  As described above, by forming the terminal plates 23 to 26 from the integrated lead frame A, the terminal plates 23 to 26 can be connected to the integrated circuit chip 22 or the like without using the printed wiring board. it can.

  In the present embodiment, two grooves D are formed along the terminal plates 23 to 25 on the surface of the molding material F on which the chip capacitors 28 are mounted. Therefore, the surplus of the silver paste 29 for bonding both electrodes of the chip capacitor 28 flows into the respective grooves D as shown in FIG. Therefore, the possibility that the silver pastes 29 at both ends of the chip capacitor 28 come into contact with each other is reduced, and a short circuit between the electrodes of the chip capacitor 28 can be suppressed.

  Note that the chip capacitor 28 is not necessarily provided in both the input terminal plate 23 and the output terminal plate 25, and may be provided in only one of them.

  In the above embodiment, the pressure sensor device for detecting pressure is exemplified as the sensor device, but the sensor device to which the technical idea of the present invention can be applied is not limited to the pressure sensor device, and chip components are mounted. Any sensor device may be used.

DESCRIPTION OF SYMBOLS 1 Sensor apparatus 2 Sensor block 21 Pressure sensor chip 22 Integrated circuit chip 23 Input terminal board 24 Ground terminal board 25 Output terminal board 28 Chip capacitor 29 Silver paste F Molding material D Groove

Claims (1)

A sensor unit having a sensor element for detecting a physical quantity and generating an electrical signal corresponding to the detected physical quantity, an input terminal board and an output terminal board connected to the sensor part, a ground terminal board, and these terminal boards An insulator interposed in a gap between each other, a chip capacitor straddling the insulator and spanning between the input terminal plate or the output terminal plate and the ground terminal plate, and both electrodes of the chip capacitor A conductive adhesive that adheres to the terminal plate, and a case in which a terminal hole that accommodates the sensor portion and exposes one end of each terminal plate is formed,
Two grooves that do not intersect each other for allowing the conductive adhesive to flow in are formed along the direction intersecting the bridge direction of the chip capacitor on the surface of the insulator sandwiched between both electrodes of the chip capacitor. A sensor device characterized by that.

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