JP2018072170A - Inertial force sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a module mounting structure for inertial force detection sensor with high reliability that suppresses output variation of an inertial force detection sensor, mounted on the circuit board, due to stress application while easily forming both top and reverse surfaces of a circuit board into a water-proof structure.SOLUTION: A gauge sensor internally comprising a semiconductor element so as to detect inertial force is mounted on a mount substrate which comprises a wiring pattern capable of electrically connecting the gauge sensor and electronic components together, and the mount substrate comprises a connector for taking a signal out from a semiconductor element for detecting inertial force, and is fixed to a step of an internal wall in a housing made of a resin material provided with the step comprising a plurality of recessed parts at an inner wall part. A connector terminal attached to a connector and the mount substrate are electrically connected with a wire, and a cover is bonded to an opening part of the housing so as to package the mount substrate, mounted with the gauge sensor and electronic components, and the wire in the housing. The housing is filled with a resin coating material, and the wire and both surfaces of the mount substrate are covered with a resin coating material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sensor device that detects an inertial force that is casing a state where an inertial force detection sensor that detects acceleration and angular velocity is mounted on a circuit board together with electronic components, and is particularly disposed in an environment where high waterproofness is required. The present invention relates to a module mounting structure of a highly reliable inertial force sensor device.

  In recent years, sensor devices that detect various physical quantities have been used in automobiles, agricultural machines, construction machines, and the like in order to improve running stability control, safety, and workability. In automobiles, applications such as acceleration sensors and angular velocity sensors are expanding for controlling devices (for example, airbags) for preventing skidding and improving passenger safety. In addition, when the sensor device is applied to an automobile, it is assumed that the sensor device is mounted in an engine room. Therefore, it is necessary to withstand severe environmental loads such as changes in temperature and humidity, and mechanical vibration. Agricultural machinery is used for controlling the posture of the vehicle body and for horizontal control of attached machines used for various cultivation applications in paddy fields and fields, and is used in harsh environments like automobiles.

  The acceleration sensor and angular velocity sensor installed in the sensor device use silicon (SiS) micro-machining technology (MEMS: Micro Electro Mechanical Systems) for the purpose of downsizing, multi-function / combination, and mass-productivity improvement. The detection means that has been becoming mainstream. A fine comb-like structure of silicon is formed by a fine processing technique, and an inertial force physical quantity such as acceleration or angular velocity is detected by converting a minute displacement of the comb-like structure into an electric signal.

  The sensor device is used in a state where it is mounted on a mounting board together with other electronic components. Further, the sensor device mounted on the mounting board is used in a modularized state with a housing or the like together with a connector for inputting / outputting electrical signals to / from the outside.

  Since the sensor device described above uses minute displacement as a detecting means, when stress, vibration, or impact is applied from the outside of the sensor device, displacement occurs in the fine comb tooth structure, and no inertial force is applied. But output occurs. This sensor output becomes a detection error and causes a decrease in the reliability of the sensor device.

  Therefore, it is indispensable that the detection apparatus using the silicon microfabrication technique has a mounting structure in which an external force such as stress or vibration is not applied to each physical quantity detection unit or each physical quantity detection element. In addition, in order to make it possible to install such detectors in equipment used in harsh environments such as automobile engine rooms and agricultural machinery accessories, it has a highly reliable mounting structure including water resistance. It is essential to do.

  As a mounting structure of a sensor device using a semiconductor element including this detection device, for example, a structure like a sensor device described in Patent Literature 1, Patent Literature 2, and the like is known.

  Patent Document 1 discloses a structure in which an upright boss for supporting a circuit board at the bottom of the casing and a stepped portion for supporting the periphery of the circuit board on the side surface inside the casing are disclosed. Even when the circuit board is fixed to the boss with a screw, and the circuit board vibrates up and down with the fixed boss position as a node of vibration, the step is supported so that the circuit board is vibrated downward. It has been shown that it can be suppressed.

  Similarly to Patent Document 1, Patent Document 2 discloses means for suppressing vibration of a circuit board. In this known technique, a circuit board on which an electronic device is mounted on at least one surface and a base member for fixing the circuit board are provided, and one or more protrusions are installed on one side of the circuit board, When the peripheral fixing portion is fixed to the base member, a part of the protrusion is brought into contact with the base member. Furthermore, by making the height of the protrusion higher than the peripheral fixing part height of the circuit board, the circuit board is warped in a convex shape. It is described that by warping the circuit board, the circuit board can be firmly fixed to the base member and vibration resistance is improved. In addition, since the circuit board is fixed at the periphery and the protrusion, the resonance frequency of the circuit board can be moved to the high frequency side, and the vibration amplitude at the time of resonance of the circuit board guided by external vibration can be suppressed to a small value.

JP-A-11-284374 JP2009-111171A

  In a mounting module in which an inertial force detection sensor is mounted on a circuit board and casing is applied, if a stress or vibration is applied from the outside, the circuit board may be deformed out of plane. This deformation of the circuit board is also transmitted to the inertial force detection sensor mounted on the board, and the sensor output is also fluctuated. Sensor output fluctuation due to stress or vibration is superposed on the output originally obtained by detecting the inertial force, resulting in a detection error and a factor (problem) that lowers the reliability of the inertial force detection sensor. In addition, in a mounting module that is mounted on an agricultural machine accessory and is not covered with a cover or the like, if water or mud is applied directly, water may be applied to the circuit board. The water on the circuit board causes a short circuit between the electrodes of the inertial force detection sensor and the electronic component mounted on the circuit board. A short circuit between electrodes on a circuit board due to water becomes a problem of an inertial force detection sensor for mounting an agricultural machine accessory.

  In Patent Document 1, the circuit board vibration in the downward direction can be suppressed by supporting the periphery of the circuit board with a stepped portion provided on the inner surface of the side wall of the housing. However, since the circuit board periphery and the stepped portion are in contact with each other, when the back side of the circuit board is waterproof, the back side of the circuit board is waterproofed with a waterproof coating material before fixing the circuit board to the housing. Need to be processed.

  In the conventional technique of Patent Document 2, since the protrusion provided on one side of the circuit board is in contact with the base member, as in the conventional technique of Patent Document 1, when the back surface side of the circuit board has a waterproof structure, Before the substrate is fixed to the housing, it is necessary to waterproof the back surface of the circuit board using a waterproof coating material or the like. Further, it is possible to obtain an effect of firmly fixing the circuit board to the base substrate by warping the circuit board by making the protrusion part higher than the peripheral fixing part. However, when the circuit board is warped, warping deformation occurs in the circuit board and various components mounted thereon, and there is a problem that excessive stress is generated in the solder connection portion and breaks. Also, when mounting a sensor component that detects inertial force such as acceleration, warpage deformation of the circuit board is also transmitted to the sensor component mounted on the circuit board, resulting in sensor output fluctuation due to stress application, This may cause detection errors.

  An object of the present invention is to provide a module mounting of a highly reliable inertial force detection sensor that suppresses fluctuations in output due to stress applied to the inertial force detection sensor mounted on the circuit board while easily providing a waterproof structure on both sides of the circuit board. Is to provide a structure.

  In order to achieve this object, in the inertial sensor device of the present invention, a gauge sensor for detecting an inertial force is mounted on one surface side, an electronic component is mounted on the other surface side, and a signal of the mounting substrate An inertial force sensor device in which the mounting board is held by the housing, so that the four corners of the mounting board are not fixed to the housing. The portion for holding the mounting substrate has a stepped shape formed by providing recesses at four corners, and the resin coating material filled in the housing covers both one side and the other side of the mounting substrate. It is characterized by.

  The step portion provided on the inner wall portion of the housing is provided with a concave portion at the corner when the mounting substrate is fixed, so that the corner portion of the mounting substrate is not fixed, and stress application to the mounting substrate can be reduced. it can. By reducing the stress applied to the mounting board, it is possible to suppress warping deformation of the mounting board, etc., so it is possible to suppress the occurrence of sensor output fluctuation due to the stress applied to the gauge sensor mounted on the mounting board. is there.

  By providing a plurality of recesses provided in the step portion on the inner wall of the housing, the periphery of the mounting substrate including the back side of the mounting substrate and the inside of the housing can be filled with, for example, a resin coating material. By filling the resin coating material or the like, both the front and back surfaces of the circuit board and the wire can be waterproofed to increase water resistance. In the housing with improved water resistance, it is possible to prevent the occurrence of problems such as an inertial force detection sensor mounted on a circuit board and a short circuit between electrodes of an electronic component even if water enters.

  According to the present invention, since it is possible to reduce the stress application to the mounting substrate, the deformation of the mounting substrate can be suppressed even when an external force such as a thermal stress due to environmental temperature change is applied. Since an external force such as a stress applied to a semiconductor element for detecting an inertial force in the gauge sensor mounted on the sensor can be suppressed, output fluctuations and measurement errors of the inertial force sensor device can be reduced.

  In addition, by filling the periphery of the mounting board including the back side of the mounting board and the inside of the housing with a resin coating material or the like, the front and back surfaces of the circuit board and the wires have a waterproof structure, and water resistance can be improved. As a result, it is possible to prevent the occurrence of problems such as a short circuit between the electrodes of the inertial force detection sensor and the electronic component mounted on the circuit board.

  With the above-described configuration of the present invention, the front and back surfaces of the circuit board of the inertial force sensor device can be easily waterproofed, and the reliability of the inertial force detection sensor mounted on the circuit board is suppressed by fluctuations in output due to stress application. A module mounting structure for a high inertial force detection sensor can be provided.

It is a cross-sectional schematic diagram of the inertial force sensor apparatus by this invention. It is a top view of the inertial force sensor apparatus by this invention. It is a top perspective view of the inertial force sensor device according to the present invention. It is a cross-sectional schematic diagram of the housing of the inertial force sensor device according to the present invention. It is a top view of the housing of the inertial force sensor device according to the present invention.

  Hereinafter, the configuration of the inertial force sensor device according to the first embodiment will be described.

  As shown in FIG. 1 and FIG. 2, an inertial force sensor device according to the present invention houses a semiconductor element (not shown) for detecting inertial force, and the periphery of the semiconductor element for detecting inertial force. For example, a package is formed by covering the substrate with a resin, or a gauge sensor 1 packaged by mounting the periphery of a semiconductor element for detecting inertial force in a case molded with resin. The gauge sensor 1 is mounted on a multi-layer mounting board 2 having an electrically connectable wiring structure, and an electronic component 10 is mounted on the other surface of the mounting board 2. As shown in FIG. 3, the mounting substrate 2 is bonded to the upper step surface of the step 11 provided on the inner wall portion of the resin housing 3 provided with the connector 7 for taking out the signal of the semiconductor element for detecting the inertial force. It is fixed with agent 6 or the like. The connector terminal 8 and a terminal (not shown) on the mounting substrate 2 are electrically connected by an aluminum wire 12 or the like, and a signal of a semiconductor element that detects inertial force can be taken out to the outside. The periphery of the mounting substrate 2 and the inside of the housing 3 are filled with a resin coating material such as gel 9. A cover 4 is bonded to the opening of the housing 3 with an adhesive 6 or the like to form a module structure.

  As shown in FIG. 4 and FIG. 5, the step 11 constituted by the recess 5 provided on the inner wall portion of the housing 3 is provided with the recess 5 at, for example, four corners corresponding to the corner when the mounting substrate 2 is fixed. Since the corners of the mounting substrate 2 are not fixed, the corners of the mounting substrate 2 are not restrained, so that stress such as thermal stress is applied to the mounting substrate 2 and deformation such as warpage is prevented. doing. Thereby, it is possible to suppress the occurrence of sensor output fluctuation due to the application of stress to the gauge sensor 1 mounted on the mounting substrate 2.

  In other words, the lower side of the step 11 (bottom side of the housing 3) is arranged to be four corners, and the higher side of the step 11 (opening side of the housing) is arranged not to be four corners. As a structure in which the four corners of the mounting substrate 2 are not fixed, the stress applied from the housing 3 to the mounting substrate 2 can be reduced.

  As shown in FIG. 3, the gauge sensor 1 is provided on the mounting substrate 2 at a distance from the recess 5 provided in the step 11 or on the inner wall portion of the housing 3 where the mounting substrate 2 is fixed with an adhesive 6 or the like. By mounting on the mounting substrate 2 on the step 11 or on the mounting substrate 2 at a distance close to the step 11 provided on the inner wall portion of the housing 3 where the mounting substrate 2 is fixed with an adhesive 6 or the like, vibration is generated from the outside. Even if vibration is transmitted to the mounting substrate 2, the mounting substrate 2 may be configured such that out-of-plane deformation hardly occurs. Thereby, it is possible to suppress the occurrence of sensor output fluctuation due to the application of vibration to the gauge sensor 1 mounted on the mounting substrate 2.

  With the configuration of the present invention described above, even when stress or vibration is applied from the outside, out-of-plane deformation (stress deformation or resonance deformation) of the mounting substrate 2 can be reduced, and the housing 3 can be mounted on the mounting substrate. The external force propagating to the gauge sensor 1 via 2 can be suppressed. As a result, output fluctuations or output errors of the inertial force sensor device can be suppressed.

  Further, since the mounting substrate 2 is fixed to the upper surface of the step 11 by connecting the mounting substrate 2 and the connector terminal 8 with the aluminum wire 12, the resin coating such as gel 9 is provided. When the material is filled into the housing 3, the coating material can reach the back side (other surface side) of the mounting substrate 2 through the recess 5. Therefore, since the entire interior of the housing 3 can be filled with a coating material or the like, both surfaces of the mounting substrate 2 can be protected with the coating material. Since the resin coating material such as gel 9 can be filled after the aluminum wire 12 is connected, the entire housing 3 including the aluminum wire 12 has a waterproof structure, and water resistance can be improved. The inside of the housing with improved water resistance can prevent a short circuit between the aluminum wires 12 and a short circuit between the electrodes of the gauge sensor 1 and the electronic component 10 even if water enters, and the inertial force sensor device. As a result, the reliability can be improved.

As mentioned above
The semiconductor element for detecting the inertial force of the present invention has a function for detecting acceleration and a function for detecting angular velocity, and the inertial force sensor may be configured by combining them alone or in combination. .

DESCRIPTION OF SYMBOLS 1 ... Gauge sensor, 2 ... Mounting board, 3 ... Housing, 4 ... Cover, 5 ... Recessed part, 6 ... Adhesive, 7 ... Connector, 8 ... Connector Terminal, 9 ... Gel, 10 ... Electronic component, 11 ... Step, 12 ... Aluminum wire

Claims (6)

A mounting board on which a gauge sensor for detecting inertial force is mounted on one side and electronic components are mounted on the other side;
A housing including a connector for transmitting a signal of the mounting board to the outside,
In the inertial force sensor device in which the mounting substrate is held in the housing,
A portion for holding the mounting board of the housing has a step shape so that the four corners of the mounting board are not fixed to the housing.
The inertial force sensor device, wherein the resin coating material filled in the housing covers both one side and the other side of the mounting substrate.   2. The inertial force sensor device according to claim 1, wherein a main component of the resin coating material is silicone gel.   The inertial force sensor device according to claim 1, wherein the housing includes an opening, and the opening is covered with a cover.   The inertial force sensor device according to any one of claims 1 to 3, wherein the gauge sensor is arranged on a mounting substrate on a step where the mounting substrate is fixed.   The inertial force sensor device according to any one of claims 1 to 3, wherein the gauge sensor is arranged at a distance far from a recess provided to form the step shape.   The inertial force sensor device according to any one of claims 1 to 5, wherein the gauge sensor has a function of detecting angular velocity and acceleration.

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