Sensor assembly with overload stop - Patents.com

Abstract

To provide a sensor assembly having an excessive load stopper.SOLUTION: A sensor assembly 100 includes: a sensor 110; and an excessive load stopper 120 arranged in a surface 116 of the sensor 110. The sensor 110 includes an elastic middle region 112 and an external region 114 surrounding the middle region 112. The excessive load stopper 120 includes a middle stopper 122 arranged in the center region 112 and a periphery stopper 124 arranged in the external region 114.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a sensor assembly, and more particularly to a sensor assembly having an overload stop. [Background technology]

[0002] A deflectable sensor membrane can be used as a force sensor. An applied force (applied force) causes the sensor membrane to deflect. The sensor membrane is a piezoresistive device whose resistance changes with deflection. The change in resistance produces a differential voltage corresponding to the deflection and applied force, causing the sensor membrane to output an electrical signal representative of the applied force. Summary of the Invention [Problem to be solved by the invention]

[0003] Generally, an intermediate element is disposed on the deflectable sensor membrane to receive and transmit the applied force to deflect the sensor membrane. However, the contact point between the intermediate element and the sensor membrane can move along the surface of the sensor membrane and is difficult to control, which can lead to inaccurate deflection and therefore inaccurate measurement of the applied force. Furthermore, when the applied force is large, the deflectable sensor membrane can continue to deflect beyond the maximum allowable deflection point, which can lead to membrane damage, inaccurate measurement, and replacement costs. [Means for solving the problem]

[0004] The sensor assembly includes a sensor and an overload stop disposed on a surface of the sensor. The sensor has a resilient central region and an outer region surrounding the resilient central region. The overload stop includes a central stop disposed in the central region and a peripheral stop disposed in the outer region.

[0005] The invention will now be described, by way of example only, with reference to the accompanying drawings in which: [Brief description of the drawings]

[0006] [Figure 1] FIG. 2 is a perspective view of a sensor assembly according to an embodiment with an actuation element. [Diagram 2] FIG. 2 is a side cross-sectional view of the sensor assembly with the actuating element in a first position. [Diagram 3] 1 is a side cross-sectional view of the sensor assembly with the actuating element in a second position. FIG. [Figure 4] FIG. 2 is a side cross-sectional view of a sensor package according to an embodiment. [Diagram 5] FIG. 5 is a top view of the elastomer of the sensor package shown in FIG. 4. [Figure 6] FIG. 11 is a side cross-sectional view of a sensor package according to another embodiment. [Figure 7] FIG. 11 is a side cross-sectional view of a sensor package according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Exemplary embodiments of the present disclosure are described in detail below with reference to the accompanying drawings in which like reference numerals refer to like elements. However, the present disclosure can be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will fully convey the concept of the present disclosure to those skilled in the art. Furthermore, in the following detailed description, for the purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. However, it is apparent that one or more embodiments can be practiced without these specific details.

[0008] A sensor assembly 100 according to one embodiment of the present invention is shown in Figures 1-3 together with an actuating element 200. The sensor assembly 100 includes a sensor 110 and an overload stop 120 disposed on the sensor 110.

[0009] The sensor 110 has a central region 112 and an outer region 114 surrounding the central region 112, as shown in Figs. 1 to 3. The central region 112 elastically deflects under an applied force in a deflection direction D1 shown in Figs. 2 and 3. The central region 112 may also be referred to as an elastic central region 112 in this specification. The outer region 114 is thicker in the direction D1 than the central region 112 and has a stiffness greater than that of the central region 112. The central region 112 has a maximum deflection 112d in the direction D1 shown in Fig. 3, and further deflection of the central region 112 would result in damage to the sensor 110. The maximum deflection 112d occurs at a maximum deflection position 115, which is in the center of the central region 112.

[0010] The sensor 110 is a piezoresistive device whose resistance changes in response to mechanical deformation applied to the sensor 110. In the embodiment shown, the sensor 110 is a piezoresistive force sensor die that produces a differential voltage corresponding to the deflection of a central region 112 in a deflection direction D1 under an applied force.

[0011] 2 and 3, the sensor 110 has a surface 116 and an electrical pad 118 disposed on the surface 116. The electrical pad 118 is disposed on the surface 116 in the outer region 114 and is formed of a conductive material. A differential voltage generated by a deflection of the central region 112 can be output from the sensor 110 through the electrical pad 118. The sensor 110 has a bottom surface 117 opposite the surface 116 in the deflection direction D1, and a pair of side surfaces 119 extending between the surface 116 and the bottom surface 117 in the deflection direction D1.

[0012] The overload stop 120 is disposed on the surface 116 of the sensor 110, as shown in Figures 2 and 3, and includes a center stop 122 and a peripheral stop 124. The center stop 122 is disposed in the central region 112, and the peripheral stop 124 is disposed in the outer region 114. The center stop 122 is disposed at a maximum deflection location 115 of the central region 112. As shown in Figure 2, the center stop 122 protrudes a first distance 122d from the surface 116, and the peripheral stop 124 protrudes a second distance 124d from the surface 116. The first distance 122d is greater than the second distance 124d. In one embodiment, the center stop 122 and the peripheral stop 124 are each formed of an insulating material. In another embodiment, the center stop 122 and the peripheral stop 124 are each formed of a conductive material.

[0013] In the embodiment shown in Figures 2 and 3, the overload stop 120 is formed on the surface 116 by depositing material on the surface 116. In one embodiment, the center stop 122 and the peripheral stop 124 are each formed of multiple film layers deposited on the surface 116. In various embodiments, the center stop 122 and the peripheral stop 124 forming the film layers can be provided using a plasma-enhanced chemical vapor deposition (PECVD) or 3D printing process. Depositing the overload stop 120 as multiple film layers secures the overload stop 120 to the surface 116, and the first distance 122d and the second distance 124d are determined by the number of film layers deposited. In various embodiments, the center stop 122 and the peripheral stop 124 are each formed of multiple layers of an insulating material, such as silicon dioxide. In another embodiment, the central stop 122 and the peripheral stop 124 are each formed from multiple layers of conductive material.

[0014] The use of the sensor assembly 100 to measure the applied force by the actuation element 200 will be described in more detail with reference to Figures 2 and 3. The actuation element 200 has an actuation surface 210 arranged to face the surface 116 of the sensor 110, as shown in Figures 2 and 3. The actuation element 200 is movable under the applied force along a deflection direction D1 between a first position P1 and a second position P2.

[0015] In the first position P1 shown in FIG. 2, the actuating element 200 is not subjected to an applied force, the central region 112 of the sensor 110 is not deflected, and the voltage output from the sensor 110 indicates that the actuating element 200 is not subjected to an applied force.

[0016] As the actuation element 200 is subjected to an applied force, it moves from a first position P1 towards a second position P2 as shown in Figure 3. The actuation surface 210 contacts the central stop 122 while moving from the first position P1 towards the second position P2, and after the initial contact with the central stop 122, the actuation element 200 moves further in the deflection direction D1, thereby deflecting the central region 112 at the maximum deflection position 115. The fixed position of the central stop 122 ensures that the central region 112 deflects at the maximum deflection position 115 when the actuation element 200 is between the first position P1 and the second position P2, thereby ensuring an accurate measurement of the force acting on the actuation element 200. The central stop 122 and the peripheral stop 124 have a stiffness greater than the stiffness of the central region 112, such that the central stop 122 and the peripheral stop 124 do not deflect under a force sufficient to deflect the central region 112. The deflection of the central region 112 corresponds to the force experienced by the actuating element 200 when the actuating element 200 is disposed between the first position P1 and the second position P2.

[0017] 3 corresponds to maximum deflection 112d of central region 112. When actuation element 200 is subjected to sufficient force to reach second position P2, actuation surface 210 contacts peripheral stop 124 in addition to central stop 122. Contact of actuation surface 210 with peripheral stop 124 disposed in stiffer outer region 114 supports actuation element 200 and prevents further deflection of central region 112.

[0018] As shown in Figures 2 and 3, the maximum deflection of the central region 112 that the overload stop 120 allows is equal to the difference between the first distance 122d and the second distance 124d. In the embodiment shown, the difference between the first distance 122d and the second distance 124d is equal to the maximum deflection 112d of the central region 112 at the second position P2. The deflection of the central region 112 does not increase beyond the maximum deflection 112d even if the force acting on the actuating element 200 increases from the second position P2. The overload stop 120 consequently prevents excessive force acting on the actuating element 200 from damaging the central region 112. In other embodiments, the difference between the first distance 122d and the second distance 124d may be less than the maximum deflection 112d.

[0019] As shown in FIG. 4, a sensor package 10 according to one embodiment includes a sensor assembly 100, an actuating element 200, a housing 300 that accommodates the sensor assembly 100 and the actuating element 200, and an elastomer 400 disposed within the housing 300.

[0020] 4, the housing 300 includes an upper portion 310 and a lower portion 320 that mate to define a receiving space 330. The upper portion 310 and the lower portion 320 are each formed of an insulating material. The upper portion 310 has a top passage 312 extending therethrough, and the lower portion 320 has a bottom passage 322 extending therethrough.

[0021] 4, the housing 300 includes an electrical contact 340 formed of a conductive material disposed on a portion of the housing 300. In the embodiment shown, the electrical contact 340 is disposed on the lower portion 320 and extends from an inner surface of the lower portion 320 adjacent the receiving space 330, along a surface of the bottom passage 322, to an outer surface of the lower portion 320 opposite the receiving space 330.

[0022] The elastomer 400 is formed of a resilient material and includes a conductive portion 410 and a non-conductive portion 420, as shown in Figures 4 and 5. In one embodiment, the conductive portion 410 and the non-conductive portion 420 are each formed of a biocompatible material. In the embodiment shown, the non-conductive portion 420 is formed of polydimethylsiloxane (PDMS) and the conductive portion 410 is formed of PDMS with a conductive composition, such as carbon nanopowder, dispersed in the PDMS. The conductivity of the conductive portion 410 can be adjusted by varying the percentage of the conductive composition in the PDMS.

[0023] 4 and 5, elastomer 400 is a rectangular, elongated member extending from a first end 402 to a second end 404 and having an elastomer passageway 430 extending generally through the center of elastomer 400. A plurality of conductive portions 410 are disposed on opposite sides of elastomer passageway 430, partially surrounded by non-conductive portions 420. Elastomer 400 is shown in a top view in FIG. 5, with dashed line 4-4 indicating a cross section of elastomer 400 shown in FIG.

[0024] As shown in FIG. 4, the sensor assembly 100 , the actuating element 200 , and the elastomer 400 are disposed within a receiving space 330 of a housing 300 to form the sensor package 10 .

[0025] In the embodiment shown in FIG. 4 , the elastomer 400 is folded around the sensor assembly 100 such that the portion of the elastomer 400 adjacent the elastomer passage 430 is disposed between the surface 116 of the sensor 110 and the upper portion 310 of the housing 300, the first end 402 and the second end 404 are disposed between the bottom surface 117 of the sensor 110 and the lower portion 320 of the housing 300, and a portion of the elastomer 400 is disposed between the side surface 119 of the sensor 110 and the upper portion 310 of the housing 300. The receiving space 330 is sized such that the elastomer 400 is compressed within the housing 300 and resiliently bears against the sensor assembly 100, securing the sensor assembly 100 within the receiving space 330. The conductive portions 410 of the elastomer 400 abut the electrical pads 118 and the electrical contacts 340, electrically connecting the electrical pads 118 to the electrical contacts 340.

[0026] 4, actuating element 200 is disposed within top passage 312 and elastomeric passage 430 and is movable within top passage 312 and elastomeric passage 430 along a deflection direction D1 to deflect central region 112 as described in detail above with reference to Figures 2 and 3. A differential voltage corresponding to the deflection of central region 112 output through electrical pads 118 is transmitted through conductive portion 410 and through electrical contacts 340 to an element external to sensor package 10.

[0027] Another embodiment of a sensor package 10' is shown in Figure 6. Like reference numerals refer to like elements and only the differences relative to the sensor package 10 shown in Figure 4 will be described in detail.

[0028] In the sensor package 10', as shown in FIG. 6, electrical contacts 340' are disposed on the upper portion 310 of the housing 300 and extend along the inner surface of the upper portion 310, between the upper portion 310 and the lower portion 320, and to the outer surface of the upper portion 310.

[0029] 6 is shorter than the elastomer 400 shown in FIGS. 4 and 5 and does not extend around the sides and bottom of the sensor 110. The elastomer 400' is disposed between the surface 116 and the upper portion 310 of the housing 300 and electrically connects the electrical pads 118 to electrical contacts 340' disposed on the upper portion 310 of the housing 300. The bottom 117 of the sensor 110 abuts the lower portion 320 of the housing 300 and compression of the elastomer 400' against the surface 116 secures the sensor assembly 100 in the receiving space 330.

[0030] Another embodiment of a sensor package 10'' is shown in FIG. 7. Like reference numerals refer to like elements and only the differences relative to the sensor package 10 shown in FIG. 4 will be described in detail.

[0031] In sensor package 10'', as shown in FIG. 7, housing 300' includes upper portion 310' and lower portion 320' that mate to define receiving space 330 and circuit space 350. Electrical contacts 340'' are disposed on an inner surface of lower portion 320' in both receiving space 330 and circuit space 350. Electrical contacts 340'' extend through lower portion 320' and are also disposed on an outer surface of lower portion 320'.

[0032] The elastomer 400″ shown in the embodiment of FIG. 7 has an L-shaped cross-section. The elastomer 400″ is disposed between the surface 116 and the upper portion 310′ of the housing 300′ and electrically connects the electrical pads 118 to electrical contacts 340″ disposed on the lower portion 320′ of the housing 300′. The bottom 117 of the sensor 110 abuts the lower portion 320′ of the housing 300′ and the compression of the elastomer 400″ against the surface 116 and between the upper portion 310′ and the lower portion 320′ secures the sensor assembly 100 in the receiving space 330.

[0033] The sensor package 10" includes an integrated circuit 500 disposed within the circuit space 350 and electrically connected to the sensor 110 through electrical contacts 340", as shown in FIG. 7. The integrated circuit 500 receives a differential voltage output through the electrical pads 118 corresponding to the deflection of the central region 112 and converts the voltage output into a digital signal that can be communicated to elements external to the sensor package 10" through the electrical contacts 340".

Claims

1. - a sensor (110) having a resilient central region (112) and an outer region (114) surrounding said resilient central region (112); - an overload stop (120) disposed by depositing material on a surface (116) of said sensor (110), said overload stop (120) including a central stop (122) disposed in said elastic central region (112) and peripheral stops (124) disposed in said outer regions (114), A sensor assembly (100).

2. both the central stop (122) and the peripheral stop (124) protrude from the surface (116) of the sensor (110); the central stop (122) protruding from the surface (116) of the sensor (110) a first distance (122d); the edge stop (124) projects a second distance (124d) from the surface (116) of the sensor (110); The first distance (122d) is greater than the second distance (124d); The sensor assembly (100) of claim 1.

3. a difference between the first distance (122d) and the second distance (124d) is less than or equal to a maximum deflection (112d) of the elastic central region (112); The sensor assembly (100) of claim 2.

4. the central stop (122) is fixed on the surface (116) of the sensor (110) at a position of maximum deflection (115) of the elastic central region (112); The sensor assembly (100) of claim 1.

5. the sensor (110) being a piezoresistive force sensor die; The sensor assembly (100) of claim 1.

6. A sensor package (10) comprising a sensor assembly (100) and an actuation element (200), The sensor assembly (100) includes a sensor (110) and an overload stop (120) disposed by depositing material on a surface (116) of the sensor (110); The sensor (110) has a resilient central region (112), the overload stop (120) includes a central stop (122) disposed in the resilient central region (112), and the actuating element (200) is movable between a first position (P1) and a second position (P2) and biases the central stop (122) to deflect the elastic central region (112) in a deflection direction (D1) during movement between the first position (P1) and the second position (P2); A sensor package (10).

7. The sensor (110) has an outer region (114) surrounding the elastic central region (112); The overload stop (120) further includes a peripheral stop (124) disposed in the outer region (114). The sensor package (10) of claim 6.

8. the second position (P2) of the actuation element (200) corresponds to a maximum deflection (112d) of the elastic central region (112); The actuating element (200) engages the central stop (122) in the second position (P2). and contacting said peripheral stop (124); The sensor package (10) of claim 7.

9. The sensor assembly further includes a housing (300) that houses the sensor assembly (100), and an elastomer (400) disposed between the sensor assembly (100) and the housing (300), The elastomer (400) has a conductive portion (410) and a non-conductive portion (420). The sensor package (10) of claim 6.

10. the non-conductive portion (420) of the elastomer (400) is formed of polydimethylsiloxane; The conductive portion (410) of the elastomer (400) is formed of polydimethylsiloxane having a conductive composition dispersed therein. The sensor package (10) of claim 9.

11. The conductive portion (410) of the elastomer (400) electrically connects the electrical pads (118) of the sensor (110) with electrical contacts (340) disposed on the housing (300). The sensor package (10) of claim 9.

12. the elastomer (400) is disposed between the surface (116) of the sensor (110) and the housing (300), between the side (119) of the sensor (110) and the housing (300), and / or between the bottom surface (117) of the sensor (110) and the housing (300); The sensor package (10) of claim 9.

13. further comprising an integrated circuit (500) disposed within the housing (300) and electrically connected to the sensor (110). The sensor package (10) of claim 9.

14. providing a sensor (110) having a resilient central region (112) configured to be resiliently deflectable and an outer region (114) surrounding said resilient central region (112); depositing an overload stop (120) on a surface (116) of the sensor (110), the overload stop (120) including a central stop (122) disposed in the resilient central region (112) and peripheral stops (124) disposed in the outer regions (114); A method for forming a sensor assembly (100).

15. the depositing step forms each of the central stop (122) and the peripheral stop (124) as a plurality of film layers on the surface (116) of the sensor (110); The method of claim 14.

16. A sensor package (10) comprising a sensor assembly (100) and an actuating element (200), The sensor assembly (100) includes a sensor (110) and an overload stop (120) disposed on a surface (116) of the sensor (110); The sensor (110) has a resilient central region (112), the overload stop (120) includes a central stop (122) disposed in the resilient central region (112), and the actuating element (200) is a sensor package (10) movable between a first position (P1) and a second position (P2) and biases the central stop (122) to deflect the elastic central region (112) in a deflection direction (D1) during movement between the first position (P1) and the second position (P2); The sensor assembly further includes a housing (300) that houses the sensor assembly (100), and an elastomer (400) disposed between the sensor assembly (100) and the housing (300), The elastomer (400) has a conductive portion (410) and a non-conductive portion (420). A sensor package (10).

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