JP2015501930A - Mechanical packaging technology for mounting MEMS and flex circuits - Google Patents

Abstract

The disclosed invention provides a rugged and compact sensing device for various implementations, including automobiles, ships and other combustion technologies where low pressure and accurate pressure sensing is required during internal combustion engine processes. In one or more aspects of the present invention, a MEMS sensor connected to a flexible circuit is provided, the communication of which is preferably achieved through the use of wire bonding technology. [Selection figure] None

Description

  The present invention relates generally to combustion process technology, and more particularly to accurately measuring pressure values in an internal combustion engine (ICE).

[Cross-reference of related applications]
This application is based on US Provisional Patent Application No. 61 / 563,455, filed on November 23, 2011 with the name of the invention “MECHANIC PACKAGING TECHNIQUE OF ATTACHING MEMS AND FLEX CIRCUIT”, and the name of the invention “MECHANICAL” Claims the benefit of US Provisional Patent Application No. 61 / 577,583, filed Dec. 19, 2011, entitled “PACKAGING TECHNIQUE OF ATTACHING MEMS AND FLEX CIRCUIT”. All of these applications are hereby incorporated by reference in their entirety.

  The increasing demand for emission control from internal combustion processes has led to the development of new combustion optimization methods such as premixed compression ignition (HCCI). However, it is difficult to obtain information and data characteristics from various components during performance testing of active combustion processes. In general, operating environments such as those involving ICE equipment and combustion processes involve high temperatures, high pressures, and often corrosive working fluids and fuels. Nevertheless, information about the combustion process can be determined from various performance characteristics that occur during the process, such as the pressure generated in the combustion chamber.

  It is well known that near real-time optimization of the combustion process can be achieved through the use of a fast (fast response) pressure sensor when used protectively. However, in many cases, these technologies are used in a closed or controlled environment such as a laboratory, while real commercial applications often have insufficient experimental technology in road usage testing. Is shown. In addition, these experimental techniques may use expensive and fragile equipment, and such equipment cannot be economically optimized for ICE load testing and other environmental inconveniences that occur during normal operation. . In addition, such types of devices are often well suited for experimental environments due to instrumentation aspects that contrast with the needs of most real-world applications.

  In addition, other sensor offerings may be more fragile, but may not be performed accurately because they may require field calibration, which is not the case for automotive and other industries. It is a clear obstacle to the execution in the above-mentioned environment including. Furthermore, the sensing elements used in the current technology provide, for example, pressure sensors based on piezoelectric elements. These sensing elements may be able to withstand the severity of combustion pressures (if after various measures protecting the elements), but are expensive to assemble and operate and may be difficult to obtain .

  It is also widely accepted that microelectromechanical system (MEMS) based sensor devices are effective in achieving control goals in an environment such as ICE. Similarly, however, using a MEMS device in such an environment is partly exposed to extreme operating environments. More specifically, a major challenge in typical MEMS-based combustion detection applications is to electrically connect the sensor connection to the signal carrying conductor to ensure the integrity of the operating system during use in extreme environments. It is necessary to keep.

  Thus, what is desired is a cost effective solution that provides a reliable and accurate monitoring pressure in connection with an internal combustion process by means of a sensor, as said sensor responds to near real-time pressure changes, It is a solution that uses a sensor that has a small footprint and is capable of mobile installation, is very suitable for the operating environment of an internal combustion engine and is economically advantageous for commercial use.

  The terms device, apparatus, system, etc., as used herein, are inclusive, interchangeable and / or synonymous with each other and other similar configurations and equipment in the present invention. It will be appreciated that each has its own characteristics, functions and / or operations, which may be specific to individual performance and / or deployment.

  The present invention fulfills these needs and evolves in response to current technology, particularly in response to conventional problems and needs that have not been fully solved by currently available technology.

  One embodiment of the present invention provides a sensor assembly, which is a rigid sensor body that is adaptively configured to be connected to an internal combustion device capable of generating pressure during operation. A body including a tip and further configured to adaptively connect to an electromechanical combustion device; a pressure sensing device configured at a preset position relative to a distal opening of the tip; and A flexible cable connecting portion electrically connected to the pressure detecting device and capable of transmitting an electric signal having pressure characteristic information to the information receiving device connected to the assembly, wherein the flexible cable connecting portion is electrically A telecommunication board for communication, a flexible communication cable for electrically connecting to the information receiving device, and the sensor body And an internal communication cable that is placed and electrically connected to the pressure detection device, the electrical communication cable being electrically connected to the flexible communication cable and the internal communication cable. Is.

  Another embodiment of the present invention provides a mechanical package assembly for detecting pressure values in an internal combustion engine, the mechanical package assembly being electrically connectable via a connectable connection. An assembly body made of stainless steel that is mechanically engaged and connected to the internal combustion engine via a fastener, and a micro electromechanical system (MEMS) pressure sensor that detects pressure in the internal combustion engine, the MEMS A pressure sensor is coupled to the tip of the body located at the distal end and is electrically connected to a flexible circuit connection, the MEMS pressure sensor being preset from the opening of the tip Information that is arranged at a distance and the flexible circuit connection is connected to the assembly an electrical signal having pressure characteristic information from the MEMS pressure sensor. The flexible circuit connecting portion is disposed in the assembly body, a flexible communication cable for electrically connecting to the information receiving device, and a flexible communication cable. An internal communication cable electrically connected to the MEMS sensor is further provided, and the electrical communication cable is electrically connected to the flexible communication cable and the internal communication cable.

  A further embodiment of the present invention provides an internal combustion engine including a pressure monitoring assembly, wherein the pressure monitoring assembly is capable of electrical signal communication and is stainless steel mechanically attached to the internal combustion engine. And a micro electro mechanical system (MEMS) pressure sensor that is fixed to the distal end portion of the main body and is capable of electrical signal communication through a flexible circuit connecting portion and wire bonding, A sensor is placed less than 10 mm from the tip, and the flexible circuit connection transmits an electrical signal having the determined pressure characteristic information from the MEMS pressure sensor to a controller connected to the assembly. And the flexible circuit connecting portion transmits an electrical signal having pressure characteristic information from the MEMS pressure sensor, The flexible circuit connecting portion can be transmitted to a control device connected to the assembly, and the flexible circuit connecting portion includes a telecommunication board for telecommunication, a flexible communication cable for electrically connecting to the control device, and the assembly main body. And an internal communication cable electrically connected to the MEMS sensor, wherein the telecommunication cable is electrically connected to the flexible communication cable and the internal communication cable, and the body is the assembly. Engaging means for fixedly attaching the tip portion, the tip portion being concentrically aligned with the main body, and the tip portion being formed of a material having a thermal expansion coefficient similar to that of the MEMS pressure sensor. It is what.

  In one or more preferred embodiments, the distance from the tip of the body to the pressure sensor is less than 12 mm, improving the instantaneousness of signal transmission. Similarly, in each aspect of the present invention, the configurations available and applicable to the present invention protect the MEMS sensor from excessive mechanical stress due to thermal expansion coefficient mismatch and, for example, the operating environment of an internal combustion engine A configured arrangement of components for electrically connecting a MEMS pressure sensor to a power source and detection equipment is provided while providing operational characteristics that allow the assembly to operate within. The present invention, in various aspects, includes using a MEMS-based combustion sensor to provide a direct pressure measurement operation without requiring an additional calibration system for the internal combustion engine.

  Further embodiments, forms, objects, features, advantages, aspects and advantages of the present application will become apparent from the detailed description and drawings.

FIG. 1 illustrates an arrangement configuration of a combustion sensor according to an aspect of the present invention. FIG. 2 depicts a schematic diagram of a combustion sensor assembly according to one aspect of the present invention. FIG. 3 illustrates a partially disassembled combustion sensor according to one aspect of the present invention. FIG. 4 illustrates a MEMS pressure sensor according to one aspect of the present invention. FIG. 5 illustrates a preferred embodiment of the present invention as the electrical connection of the MEMS sensor to the output and control electronics. FIG. 6 presents a preferred embodiment of the present invention as the electrical connection of a MEMS pressure sensor that incorporates the direct attachment of the MEMS sensor to the flex circuit. FIG. 7 presents a schematic overview of the method of the present invention as attachment of a MEMS sensor to a flex circuit. FIG. 8 shows a preferred embodiment of the present invention as an electrical connection of a MEMS pressure sensor incorporating a ceramic printed circuit board between the MEMS sensor and the flex cable.

  The following description is presented to enable one of ordinary skill in the art to make and use the invention and is presented in the context of a patent application and its requirements. Various modifications and general principles and features to the preferred embodiments described herein will be readily apparent to those skilled in the art. That is, the present invention is not intended to be limited to the disclosed embodiments, but is to be accorded the widest scope consistent with the principles and features described herein.

  The disclosed invention provides a rugged and compact detection device for a variety of implementations, including automobiles, ships and other combustion technologies that require accurate pressure detection at low cost during internal combustion engine processes. In one or more aspects of the present invention, a MEMS sensor connection with a flexible circuit is provided, the communication of which is preferably achieved by using wire bonding technology.

  The present invention provides for adaptively configuring a MEMS pressure sensor to be very close to a pressure port that allows real-time pressure sensing.

  FIG. 1 illustrates an arrangement configuration of a combustion sensor according to an aspect of the present invention. From FIG. 1, the sensor body 101 has a shape and configuration that provides structural rigidity to the sensor assembly 100, along with mechanical fasteners that utilize screws 102 that engage the engagement threads of the head of an internal combustion engine (not shown). It is configured. In a preferred embodiment, sensor body assembly 101 is made from stainless steel. A suitably tapered tip 103 distal to the screw 102 forms a tight seal with the pressure port of the ICE head. In addition, since the tip 103 is preferably manufactured from a material having a thermal expansion coefficient similar to that of the MEMS assembly in the preferred embodiment, its configuration and composition reduce the temperature-induced stress acting on the pressure sensing MEMS assembly. It is configured as follows. In a preferred further embodiment of the present invention, the tip 103 is manufactured from Kovar® and is preferably attached to the sensor body 101 by laser welding (Kovar is a registered trademark of Carpenter Technology). The cable 104 provides the electrical connections necessary to communicate with other electronic devices that are connected to an assembly such as, for example, control electronics.

  FIG. 2 depicts a schematic diagram of a combustion sensor assembly 200 according to one aspect of the present invention. As shown in FIG. 2, the various positions and holding functions of the components that make up the completed assembly are shown. The tip 203 provides a proximal arrangement and interface for positioning and holding the pressure sensing element 205. In a preferred embodiment, the tip 203 is concentrically aligned with the sensor body 201 and the pressure sensor 205 is a MEMS pressure sensor. Those skilled in the art will appreciate that a MEMS sensor near the pressure port provides a near instantaneous signal and a high resonant frequency response from the MEMS sensor because the length of the air path in the tip 203 is minimized. Will be done.

  In a preferred embodiment of the invention, the distance from the MEMS sensor 205 to the farthest opening of the tip 203 is a preset distance of less than 15 mm. In a further preferred embodiment of the invention, the distance from the MEMS sensor 205 to the farthest opening of the tip 203 is a preset distance of less than 10 mm. In a more preferred embodiment of the present invention, the distance from the MEMS sensor 205 to the farthest opening of the tip 203 is a preset distance of less than approximately 8 mm and is 7.72 mm. In addition, the sensor assembly includes an internal flex cable 206 which, as shown in FIG. 3, provides the necessary electrical for circuit connection in addition to the important features for completing the electrical connection to the MEMS sensor. It has a shape preset to provide wiring.

  FIG. 3 illustrates a partially disassembled combustion sensor 300 according to one aspect of the present invention. As shown in FIG. 3, printed circuit board 307 forms an interconnection between flex cable 306 and cable 304. In a preferred embodiment, the substrate 307 and cable 304 are placed and held in the sensor body 301 by a wire cap 308 and are preferably manufactured from stainless steel. A retaining ring 109 is also preferably utilized. In various embodiments of the present invention, the printed circuit board 307 can also function structurally to further facilitate cable connections, or alternatively, one or more necessary to operate the sensor assembly. Of electronic devices.

  Further preferred embodiments relating to the electrical connection (electrical signal communication) between the MEMS sensor assembly and the conductor are shown in FIGS.

  FIG. 4 illustrates a preferred embodiment 400 of a MEMS pressure sensor according to one aspect of the present invention. FIG. 5 shows a preferred embodiment 500 of the present invention as the electrical connection of the MEMS sensor to the output and control electronics.

  As shown in FIGS. 4 and 5, the MEMS sensors 405 and 505 are permanently fixed (attached) and sealed to the tip portions 403 and 503 by eutectic bonding. In a preferred embodiment, the seal is hermetic and the flex circuits 406, 506 are bonded to the inner surface of the tips 403, 503 using high temperature epoxy resin. The wiring connection from the MEMS sensor to the flex circuit is also completed using wire bonding 410,510. As will be appreciated by those skilled in the art, the bonding wire may be a circle or rectangle of gold, aluminum or any metal suitable for wire bonding.

  A further alternative embodiment of the present invention is shown in FIGS. FIG. 6 presents a preferred embodiment 600 of the present invention as an electrical connection for a MEMS pressure sensor incorporating a MEMS sensor direct attachment to a flex circuit. FIG. 7 presents a graphical overview 700 of the method of the present invention as attachment of a MEMS sensor to a flex circuit.

  As shown in FIGS. 6 and 7, the MEMS 602 and 702 are directly attached to the flex circuits 601 and 701. In this embodiment, the MEMS sensor assembly has an aluminum bond pad or gold bump that will form an electrical connection to the flex circuit. Die pads are indicated at 603,703.

  FIG. 8 illustrates a preferred embodiment 800 of the present invention as an electrical connection of a MEMS pressure sensor incorporating a ceramic printed circuit board between the MEMS sensor and the flex cable. As shown in FIG. 8, a MEMS sensor assembly 800 is attached to the tip 805 by eutectic bonding. A ceramic spacer 802 including a wire bonding pad is attached to the upper surface of the MEMS 803. The flex circuit 801 is attached to the ceramic spacer 802. A die pad is indicated at 804.

  The present invention monitors combustion pressures of internal combustion engines, such as those used in automobiles, ships, aircraft and RV vehicles, and any movable or fixed assemblies incorporating internal combustion engines such as generators and mobile generators. Can be used in a variety of applications and implementations. It can also be incorporated into diesel engines or diesel engine applications.

  Although the invention has been described in accordance with the disclosed embodiments, those skilled in the art will readily recognize that variations may exist in the embodiments and that such variations are within the spirit and scope of the invention. Will do. The invention disclosed herein is not limited thereto, but has specific needs and / or in the automotive, marine and other industries where accurate pressure sensing is required at low cost even in harsh operating environments. Or it can be constructed in a variety of ways, including a rugged and compact detection device designed to meet suitability. Accordingly, many modifications may be made by one skilled in the art without departing from the spirit and scope of the present invention.

  While this invention has been described in terms of preferred embodiments, this is not intended to limit the invention. Indeed, embodiments of the present invention can be combined with other sensors and systems such as other temperature, fluid leveling, filtering and similar sensors. As can be seen from the above description, embodiments of the present invention are intended to be used as a sensor assembly or in combination with other types of sensors. In this regard, the above description is intended to cover all modifications and alternative constructions included within the spirit and scope of the present invention as set forth in the appended claims. There is no implied part that is intended to be dedicated to public property if it is not indicated in the claims.

Claims (20)

A sensor assembly,
A rigid sensor body adapted to be connected to an internal combustion device capable of generating pressure during operation, further comprising a tip and further adapted to adaptively connect to an electromechanical combustion device The main body,
A pressure sensing device configured at a preset position relative to the distal opening of the tip;
A flexible cable connection that is electrically connected to the pressure sensing device and capable of transmitting an electrical signal having pressure characteristic information to an information receiving device connected to the assembly;
The flexible cable connecting portion is disposed in the sensor body and electrically connected to the pressure detecting device, and the flexible communication cable is electrically connected to the telecommunication board for telecommunication, the information receiving device, and the information receiving device. And an internal communication cable, wherein the electrical communication cable is electrically connected to the flexible communication cable and the internal communication cable. The assembly of claim 1, wherein
An assembly wherein the internal combustion device is an internal combustion engine (ICE). The assembly of claim 1, wherein
An assembly wherein the pressure sensing device is a micro electromechanical system (MEMS) sensing device. The assembly of claim 3.
An assembly wherein the MEMS sensing device is a MEMS pressure sensor. The assembly of claim 1, wherein
The assembly is characterized in that the information receiving device is an electronic control unit in signal communication with the internal communication cable. The assembly of claim 1, wherein
The assembly wherein the sensor body is stainless steel and the internal communication cable is disposed within the sensor body using a wire cap. The assembly of claim 6 wherein:
The assembly wherein the sensor body further comprises engagement means for fixedly attaching the assembly to the electromechanical combustion device. The assembly of claim 7, wherein
An assembly wherein the engagement means is a screw fastener. The assembly of claim 8, wherein
The tip is aligned concentrically with the sensor body, and the tip is made of a material having a thermal expansion coefficient similar to that of the pressure detection device, and the pressure detection device is a micro electro mechanical system (MEMS). ) An assembly characterized by being a pressure sensor. The assembly of claim 9, wherein
An assembly wherein the tip is formed of a material similar to a material comprising a Kovar® brand composition. The assembly of claim 9, wherein
The assembly wherein the sensor body is attached to the tip by a welding process. The assembly of claim 9, wherein
The assembly is characterized in that the preset position is a position having a value of less than 15 mm. The assembly of claim 12, wherein
The assembly is characterized in that the preset position is a position having a value of less than 8 mm. The assembly of claim 9, wherein
An assembly wherein the telecommunications substrate is a substrate having an electronic circuit. 15. The assembly according to claim 14, wherein
The assembly wherein the pressure sensor is sealed to the tip by eutectic bonding. The assembly of claim 9, wherein
The internal combustion device is an internal combustion engine (ICE), the information receiving device is an electronic control device that performs signal communication with the internal communication cable, and the preset position is a position having a value less than 8 mm. Feature assembly. A mechanical package assembly for detecting a pressure value in an internal combustion engine,
A stainless steel assembly body which can be electrically connected via a connectable connection and is mechanically engaged and connected to the internal combustion engine via a fastener;
A micro electro mechanical system (MEMS) pressure sensor for detecting pressure in the internal combustion engine, the MEMS pressure sensor being coupled to a tip of the body disposed at a distal end, and a flexible circuit connection The MEMS pressure sensor is disposed at a preset distance from the opening of the tip,
The flexible circuit connection unit can transmit an electrical signal having pressure characteristic information from the MEMS pressure sensor to an information receiving device connected to the assembly, and the flexible circuit connection unit can transmit electrical signals for telecommunications. A communication board; a flexible communication cable for electrically connecting to the information receiving device; and an internal communication cable disposed in the assembly body and electrically connected to the MEMS sensor. An assembly, wherein a cable is electrically connected to the flexible communication cable and the internal communication cable. The assembly of claim 17, wherein
The assembly wherein the preset distance is greater than 5 mm and less than 12 mm. The assembly of claim 18, wherein
The internal combustion engine is one of an automobile engine, a generator, a marine power generation system, and a mobile combustion device, and the connectable connection is configured to transmit an electrical signal to an electronic control unit. An assembly featuring. In an internal combustion engine including a pressure monitoring assembly,
The pressure monitoring assembly comprises:
A stainless steel body capable of electrical signal communication and mechanically attached to the internal combustion engine;
A micro electromechanical system (MEMS) pressure sensor capable of electrical signal communication via a flexible circuit connection portion and wire bonding, and being fixed to the tip of the main body,
The pressure sensor is disposed less than 10 mm from the tip, and the flexible circuit connection sends an electrical signal having determined pressure characteristic information from the MEMS pressure sensor to a controller connected to the assembly. Can send,
The flexible circuit connection unit can transmit an electrical signal having pressure characteristic information from the MEMS pressure sensor to a control device connected to the assembly, and the flexible circuit connection unit performs electrical communication for electrical communication. A board, a flexible communication cable for electrical connection with the control device, and an internal communication cable disposed in the assembly body and electrically connected to the MEMS sensor, wherein the electrical communication cable comprises: Electrically connected to the flexible communication cable and the internal communication cable;
The body further comprises engagement means for fixedly attaching the assembly, the tip is concentrically aligned with the body, and the tip is made of a material having a thermal expansion coefficient similar to that of the MEMS pressure sensor. An internal combustion engine characterized by being formed.

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