Sensor assembly having a multi-range configuration
阅读说明:本技术 具有多范围构造的传感器组件 (Sensor assembly having a multi-range configuration ) 是由 陈雅媚 J.霍夫曼 于 2020-04-22 设计创作,主要内容包括:一种力传感器设备(10),包括由两个结合在一起的硅构件(14)和(16)形成的传感器管芯(12)。第一构件(14)包括第一膜片(24)和在第一膜下方的由第二构件(16)中的凹入部分(26)形成的掩埋腔(27)。第二构件包括第二膜片(44),其由第二构件的形成背面腔(36)的下表面的凹入部分(32)形成。第一膜片(24)和第二膜片(44)彼此竖直对准。第一构件包括第一组电感测元件(48),其定位在第一膜片(24)附近,第二组电感测元件(54)定位在第二膜片(44)附近。电触点(58)沿传感器管芯的表面设置,以促进与外部设备的电连接。(A force sensor device (10) includes a sensor die (12) formed of two silicon members (14) and (16) bonded together. The first member (14) comprises a first membrane (24) and a buried cavity (27) beneath the first membrane formed by a recess (26) in the second member (16). The second member includes a second diaphragm (44) formed by a recessed portion (32) of the second member forming a lower surface of the back cavity (36). The first diaphragm (24) and the second diaphragm (44) are vertically aligned with each other. The first member includes a first set of electrical sensing elements (48) positioned adjacent the first diaphragm (24) and a second set of electrical sensing elements (54) positioned adjacent the second diaphragm (44). Electrical contacts (58) are disposed along a surface of the sensor die to facilitate electrical connection with an external device.)
1. A sensor device (10) comprising:
a sensor die (12) comprising:
a first diaphragm (24) disposed between a first outer surface of the sensor die and a buried cavity (27) in the sensor die, the buried cavity (27) extending a depth from the outer surface;
A second membrane (44) disposed between the buried cavity (27) and a recessed portion (32) of a second outer surface of the sensor die opposite the first outer surface; and
electrical sensing elements (48 and 54) disposed within the sensor die for measuring movement of the first and second sensing diaphragms.
2. The sensor device of claim 1, wherein the electrical sensing elements comprise a first set of electrical sensing elements (47) positioned adjacent to the first diaphragm (24) and a second set of electrical sensing elements (54) positioned adjacent to the second diaphragm (44).
3. The sensor device of claim 1, further comprising electrical contacts (58) exposed along the first outer surface of the sensor die (12), the electrical contacts being electrically connected with the electrical sensing element.
4. The sensor device of claim 1, wherein the electrical sensing elements (48 and 54) are disposed within a region of the sensor die between the first outer surface and the buried cavity (27).
5. The sensor device of claim 1, wherein the first diaphragm (24) is dimensioned to have a length different from a length of the second diaphragm (44).
6. The sensor device of claim 1, wherein a thickness of the first diaphragm (24) is different from a thickness of the second diaphragm (44).
7. The sensor device of claim 1, wherein the buried cavity (27) comprises a port extending to the environment outside the sensor die.
8. The sensor device of claim 1, wherein the sensor die (12) comprises a first member (14) and a second member (16) attached together, wherein the buried cavity (27) is formed between the first member and the second member, and wherein the first diaphragm (24) is integral with the first member.
9. A method for sensing a force, comprising:
applying an external force to a sensor device (10) comprising a sensor die (12), the sensor die (12) having a first diaphragm (24) arranged therein and a second diaphragm (44) located adjacent to the first sensing diaphragm in a vertical direction, wherein the sensor die comprises a buried cavity (27) adjacent to the first sensing diaphragm, and wherein the external force is directed onto the first sensing diaphragm;
detecting an amount by which one or both of the first diaphragm (24) and the second diaphragm (44) deflects in response to the external force with electrical sensing elements (48 and 54) disposed within the sense die (12); and
the magnitude of the external force is determined based on an electrical sensing element output transmitted by the sensor device via electrical contacts (58) disposed on the sensor die surface.
10. The method of claim 9, wherein the first diaphragm (24) is configured to detect external forces within a first range of external force magnitudes and the second diaphragm (44) is configured to detect external forces within a second range of external force magnitudes, the second range of external force magnitudes being different from the first range of external force magnitudes.
Technical Field
The invention relates to a method and a sensor device for sensing a force.
Background
The use of sensor assemblies for determining the amount of force exerted on a sensor element, diaphragm or membrane is known in the art. To determine the amount of force applied by the physical element, a force sensor is used. Conventional force sensors include: a force sensor die comprising a diaphragm and an electrical sensing element connected thereto; and an actuation element fabricated separately from the sensor die and bonded to the sensor die such that the actuation element contacts a portion of the diaphragm. An actuating element extends from the force sensor to receive an external force that is subsequently transmitted by the actuating element to the diaphragm of the sensor die, causing deflection of the diaphragm, which is measured by the electrical sensing element and then used to provide an output that is used to determine the external force.
Such known force sensors include sensors having a buried cavity design in which a diaphragm or diaphragm may extend from the surface of the sensor die to the buried cavity and cause the diaphragm to deflect into the buried cavity when an external force is applied to the diaphragm surface. Other known force sensors have a backside cavity design in which a diaphragm or diaphragm may extend from the surface of the sensor die to the backside cavity and cause the diaphragm to deflect into the backside cavity when an external force is applied to the diaphragm surface. This known force sensor design is characterized in that the range of external forces that can be determined accurately is limited by the working deflection range of the diaphragm and the sensitivity of the diaphragm in detecting the forces exerted therein. For each of these types of known sensors, the range of external forces that can be measured accurately is therefore limited.
In certain use applications, it is desirable to determine the external force over a wide range that exceeds the capabilities of such known force sensors, for example, beyond the operating conditions under which the diaphragm or diaphragm reaches full deflection and therefore no longer has the ability to provide force measurement information. The problems to be solved are that: a sensor assembly is provided that is configured to be capable of measuring external forces over a plurality of ranges, for example, when subjected to low and high force conditions; and is configured to enable customization for the purpose of customizing the multi-range force detection capability to a particular application-use, e.g., a different degree of sensitivity may be required in one region of a range as compared to another region of the range.
Disclosure of Invention
In accordance with the present invention, the sensor devices disclosed herein generally include a sensor die that includes a first diaphragm disposed between a first outer surface of the sensor die and a buried cavity in the sensor die that extends a depth from the outer surface. The sensor die also includes a second membrane disposed between the buried cavity and a recessed portion of a second outer surface of the sensor die opposite the first outer surface. In an example, the sensor die includes a first member and a second member attached together, wherein the buried cavity is formed between the first member and the second member, and wherein the first diaphragm is integral with the first member. In one example, the second diaphragm is integral with the second member. The first diaphragm may be sized to have a length different from a length of the second diaphragm. The first diaphragm may have a thickness different from a thickness of the second diaphragm. The sensor die further includes an electrical sensing element disposed therein for measuring movement of the first and second sensing diaphragms. In an example, the electrical sensing element is disposed within a region of the sensor die between the first outer surface and the buried cavity. In an example, the electrical sensing elements include a first set of electrical sensing elements positioned adjacent to the first diaphragm and a second set of electrical sensing elements positioned adjacent to the second diaphragm. The sensor device also includes electrical contacts exposed along the first outer surface of the sensor die that are electrically connected with the electrical sensing element. In one example, the sensor device is a force sensor.
A method of determining a force applied therein using a sensor device, comprising: an external force is applied to an area of the sensor device occupied by the first sensing diaphragm, and wherein the second sensing diaphragm is disposed vertically below the first sensing diaphragm. The force exerted on the sensor device causes the first sensing diaphragm to deflect and, in some cases, the second sensing diaphragm to also deflect, with the amount of deflection of each sensing diaphragm being measured by the corresponding electrical sensing element. The electrical sensing element provides an output signal which is transmitted by the electrical connection to the exterior of the sensor device for determining the magnitude of the force by an external device electrically connected to the sensor device. In an example, the first diaphragm is configured to detect an external force within a first external force magnitude range, and the second diaphragm is configured to detect an external force within a second external force magnitude range, the second external force magnitude range being different from the first external force magnitude range.
Drawings
The sensor assembly disclosed herein will now be described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1A is a cross-sectional side view of an example sensor assembly disclosed herein;
FIG. 1B is a top view of the example sensor assembly of FIG. 1A;
FIG. 1C is a bottom view of the example sensor assembly of FIG. 1A;
FIG. 2A is a cross-sectional side view of an example sensor assembly disclosed herein;
FIG. 2B is a top view of the example sensor assembly of FIG. 2A;
FIG. 3A is a cross-sectional side view of the example sensor assembly of FIG. 1 in a first state;
FIG. 3B is a cross-sectional side view of the example sensor assembly of FIG. 1 in a second state;
FIG. 3C is a cross-sectional side view of the example sensor assembly of FIG. 1 in a fourth state;
FIG. 3D is a cross-sectional side view of the example sensor assembly of FIG. 1 in a fourth state;
FIG. 4 is a graph illustrating diaphragm deflection characteristics as a function of applied force for an example sensor assembly disclosed herein; and
FIG. 5 is a graph illustrating diaphragm sensitivity characteristics as a function of applied force for an example sensor assembly disclosed herein.
Detailed Description
Embodiments of a sensor assembly or apparatus will be described in detail below with reference to the drawings, wherein like reference numerals refer to like elements. However, the sensor assemblies disclosed herein may be implemented in many different forms and for different types of uses, and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the sensor assembly to those skilled in the art. The sensor assembly disclosed herein may be used in applications where a force exerted by a physical object is measured, where such a sensor assembly may be referred to as a force sensor. However, it should be understood that the sensor assemblies disclosed herein may be used in other types of force recording/monitoring applications beyond those that measure forces exerted on them by physical objects, such as pressure sensor applications where fluid pressure, etc., is monitored.
Fig. 1A illustrates an exemplary sensor device or
The sensor die second member 16 includes a recessed portion 26, which recessed portion 26 may be formed in the second member by an etching process or the like prior to attachment with the first member, as better described below. The recessed portion 26 is disposed directly opposite the
For example, in the example of buried cavity unvented, the sensor assembly may be used to measure pressure (pressure). In the example of buried cavity venting, the sensor assembly may be used to measure a physical force. In an example, the buried cavity is vented, and such venting may occur, for example, through a port extending from the buried cavity. The depth of the recessed portion 26, measured from the lower side surface 28 of the second member to the
The second member 16 of the sensor die includes a recessed portion 32, the recessed portion 32 being disposed along an outer surface 34 of the second member and forming a
In this example, the buried cavity 27 extends a length within the sensor die that is less than the length of the
In the example shown in fig. 1A, the buried cavity 27 extends along the sensor die a length that is less than the length of the
Referring to fig. 1A and 1B, the sensor die 12 includes a first set of
As shown in fig. 1B, in this
Fig. 1C illustrates a bottom view of the sensor die 12 of the
In one example, the sensor assembly shown in fig. 1A-1C and disclosed herein may be manufactured by: a recessed portion 32 is formed in the second member 16 of the sensor die and then the second member 16 is bonded to the first member 14, forming a buried cavity 27 therebetween. The first member
Fig. 2A and 2B illustrate an
As shown in fig. 2B, for this
Fig. 3A-3D illustrate the example sensor assembly of fig. 1A-1C in different states with respect to an external force applied thereto. Fig. 3A shows a
Fig. 3C shows the
Fig. 3D shows the
FIG. 4 is a graph 200 illustrating the amount of deflection of the first and second diaphragms or membranes as a function of applied force. The deflection characteristic of the first diaphragm is shown by curve 202, while the deflection characteristic of the second diaphragm is shown by curve 204. As shown, with increasing applied force starting from zero, the degree of deflection of the first diaphragm is greater than the degree of deflection of the second diaphragm, as can be seen from curve 202. There is a point on the graph indicated by vertical line 206 at about 0.7N indicating that the first diaphragm is in contact with the buried cavity, which operates to limit further free deflection of the first diaphragm (this condition is described above, as shown in fig. 3C). Continuing from this point, curve 204 shows that the second diaphragm exhibits increased deflection, which was slight prior to this point. Curve 204 shows the continued deflection of the second diaphragm as force is continuously applied. Thus, the graph is used to show the deflection characteristics of the first and second diaphragms of the sensor assembly along the range of applied forces (in this example, a range from 0 to about 0.7N corresponding to deflection of the first diaphragm; and a range from 0.7 to 10N corresponding to deflection of the second diaphragm), thereby operating to provide accurate information for determining the force applied thereto over the range of force pressures.
FIG. 5 is a
Features of the sensor assemblies disclosed herein include a configuration that facilitates force determination over a range of forces through the use of a first diaphragm and a buried cavity and a second diaphragm and a backside cavity, which is not possible with conventional sensor assemblies. The sensor assembly may be customized, for example, by the dimensions of the first and second diaphragms, the depth of the buried cavity, and/or the depth of the backside cavity, to provide desired measurement accuracy in different regions of the force range. Furthermore, such sensor assemblies operate to physically limit the degree of deflection of the first diaphragm by the presence of (i.e., by contact with) the buried cavity, thereby minimizing possible tearing or other failure of the first diaphragm during use, which may increase the useful life of the effective sensor assembly. Further, although the sensor assemblies disclosed herein are described in the context of being used as force sensors, they may be used in other applications such as pressure sensors and the like.
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