PRESSURE SENSORS AND METHODS OF MANUFACTURING A PRESSURE SENSOR
20220412826 · 2022-12-29
Inventors
- Vishal Shalitkumar KUSANALE (Bangalore, IN)
- Todd ECKHARDT (Columbus, OH, US)
- Palani THANIGACHALAM (Bangalore, IN)
- Vignesh Murugesan (Bangalore, IN)
Cpc classification
G01L19/148
PHYSICS
International classification
G01L19/00
PHYSICS
Abstract
A pressure sensor and method of manufacturing the like are provided for determining a pressure of a fluid. An example pressure sensor includes a pressure sensor housing sealably attached to a diaphragm at a first end. The header includes a lip configured to engageably fit with the second end of the pressure sensor housing to create a hermetically sealed component compartment. The header also includes header pin(s) configured to transmit electrical signals between an interior and an exterior of the hermetically sealed component compartment. A sensing element and a processor are disposed within the hermetically sealed component compartment and in communication with one another. The sensing element is mounted to the processor within the hermetically sealed compartment. The corresponding method of manufacture is also provided.
Claims
1.-20. (canceled)
21. A pressure sensor for determining a pressure of a fluid, the pressure sensor comprising: a pressure sensor housing sealably attached to diaphragm at first end of pressure sensing housing a header at a second end of the pressure sensor housing the header with a lip configured to engageably fit with the second end of the pressure sensor housing to create a hermetically sealed component compartment within the pressure sensor housing, wherein the diaphragm is positioned outside of the hermetically sealed component compartment; and a processor disposed within the hermetically sealed component compartment and in electrical communication with the three or more header pins.
22. The pressure sensor of claim 21, wherein the header includes three or more header pins configured to transmit an electrical signal between an interior and an exterior of the hermetically sealed component compartment.
23. The pressure sensor of claim 21, wherein a sensing element coupled to the processor and disposed within the hermetically sealed component compartment, wherein the sensing element is in electrical communication with the processor.
24. The pressure sensor of claim 23, wherein the sensing element is in a stacked relationship with respect to the processor.
25. The pressure sensor of claim 21, wherein the hermetically sealed component compartment is filled with a liquid.
26. The pressure sensor of claim 21, wherein the diaphragm is configured to be in contact on a first surface with the hermetically sealed component compartment and on a second surface with the fluid to be measured.
27. The pressure sensor of claim 21 further comprising a ceramic plate or a printed circuit board directly mounted to the header, wherein the processor is directly mounted to the ceramic plate or the printed circuit board.
28. The pressure sensor of claim 21 further comprising a protective cap configured to be attached to the first end of the pressure sensor, wherein the protective cap has at least one opening allowing the fluid to reach the diaphragm.
29. The pressure sensor of claim 21, wherein the diaphragm is configured to deflect in one direction, or another based on a difference in pressure between the hermetically sealed component compartment and the fluid to be measured, wherein the deflection of the diaphragm alters an original pressure of the hermetically sealed component compartment, wherein the sensing element is configured to measure the altered pressure of the hermetically sealed component compartment based on the deflection of the diaphragm, and wherein the processor having computer coded instructions therein, with the computer instructions configured to, when executed, cause the pressure sensor to determine the pressure of the fluid based on the altered pressure measured by the sensing element and the original pressure.
30. The pressure sensor of claim 21, wherein the sensing element and the processor have a substantially similar coefficient of thermal expansion.
31. A pressure sensor for determining a pressure of a fluid, the pressure sensor comprising: a housing, the housing having a diaphragm fixedly attached at a first end and having a second end, wherein the second end has a mating surface that defines a recess, wherein the housing defines a component compartment; a header comprising an exterior header member having a first cross-sectional diameter and interior header member having a second cross-sectional diameter, wherein the interior header member is sized to be inserted into the recess and the exterior header member is sized to mate with the mating surface such that the header hermetically seals the component compartment, wherein the diaphragm is positioned outside of the hermetically sealed component compartment; and a processor disposed within the component compartment.
32. The pressure sensor of claim 31, further comprising a sensing element disposed within the component compartment.
33. The pressure sensor of claim 31, wherein the diaphragm and the header sealably enclose the component compartment to create a hermetically sealed component compartment.
34. The pressure sensor of claim 13, wherein the diaphragm is configured to deflect in one direction or another based on a difference in pressure between the hermetically sealed component compartment and the fluid to be measured, wherein the deflection of the diaphragm alters an original pressure of the sealed component compartment, wherein the sensing element is configured to measure the altered pressure of the hermetically sealed component compartment based on the deflection of the diaphragm, and wherein the processor having computer coded instructions therein, with the computer instructions configured to, when executed, cause the pressure sensor to determine the pressure of the fluid based on the altered pressure measured by the sensing element and the original pressure.
35. The pressure sensor of claim 31 further comprising a ceramic plate or a printed circuit board directly mounted to the interior header member of the header, wherein the sensing element and the processor are mounted directly to the ceramic plate or printed circuit board.
36. The pressure sensor of claim 31 further comprising a ceramic plate directly mounted to the interior header member of the header, wherein the sensing element is mounted directly to the processor and the processor is mounted directly to the ceramic plate.
37. The pressure sensor of claim 31 further comprising a protective cap configured to be attached to the first end of the pressure sensor, wherein the protective cap has at least one opening allowing the fluid to reach the diaphragm.
38. The pressure sensor of claim 31, wherein the header includes three or more header pins configured to transmit an electrical signal between an interior and an exterior of the component compartment, and the processor is in communication with at least one of the three or more header pins.
39. A method of determining the pressure of a fluid, the method comprising: receiving an original and altered pressure of a sealed component compartment from a sensing element; and determining, via a processor, the pressure of the fluid based on a comparison between the altered pressure and the original pressure, wherein the processor and the sensing element are disposed in the sealed component compartment that is defined by a pressure sensor housing having a diaphragm at a first end of the pressure sensor housing positioned outside of the sealed component compartment and a header at a second end of the pressure sensor housing.
40. The method of determining the pressure of a fluid of claim 39, further comprising transmitting a signal relating to the determined pressure of the fluid to at least one of three or more header pins.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Having thus described certain example embodiments of the present disclosure in general terms, reference will hereinafter be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
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DETAILED DESCRIPTION
[0043] Some embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, various embodiments may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. As used herein, the term “fluid” is not intended to be limited to a liquid. Rather, the term “fluid” is intended to include any material subject to flow, such as, but not limited to, liquids and/or gases (e.g., air, oil, or the like).
[0044] The present disclosure provides example pressure sensors and method of manufacturing the same to determine the pressure of a fluid which is isolated from the sensing element. In some examples, pressure sensors are used in various applications including HVAC/R, water pump, air compressor, compressed natural gas (CNG) lines, liquefied petroleum gas (LPG) lines, automotive and transportation fluids, and the like. In many of these example applications, the environment that pressure sensors operate within consist of corrosive media which can affect performance and sometime damage the sensor. Various pressure sensors currently in operation require bigger and more expensive, and/or otherwise unsuitable sensing dies that are not packaged in an effective way to allow for cost effective, media isolating pressure sensors for widespread use.
[0045] The pressure sensor described in various embodiments herein may be used in hazardous conditions. In some example embodiments, the pressure sensor described herein includes a processor (e.g., application-specific integrated circuit (ASIC)) and sensing element (e.g., sense die with deep reactive-ion (DRIE) etched technology) that are placed or otherwise housed within a hermetically sealed component compartment of a pressure sensor. In some embodiments, the sensing element is mounted to the processor in a stacked relationship. Alternatively or additionally, the sensing element and processor may be disposed within the hermetically sealed component compartment of a pressure sensor in other arrangements, such as a side-by-side relationship.
[0046] Referring now to
[0047] In an example embodiment, the pressure sensor housing 120 may have a diaphragm opening at a first end 30 and a header opening at a second end 35. While the diaphragm opening and the header opening may be the same size, in some embodiments, the header opening may be larger than the diaphragm opening in others. In some example embodiments, the pressure sensor housing 120 may be configured with a circular cross-section although other shapes may be contemplated, such as a rectangular cross section, in view of the examples described herein. The pressure sensor housing 120 may be formed from metal or any other suitable material.
[0048] The header 110 may likewise be configured with a circular cross-section, in some examples, and may include at least one header pin 105 configured to transmit electrical signals between the interior and the exterior of the pressure sensor 100. In some embodiments, the header 110 may have three or more header pins 105 (e.g., a header may have three header pins). In some embodiments, the header 110 may have as many as eight header pins 105. In some embodiments, three or more header pin seals 50, as shown in
[0049] As shown in various figures, such as
[0050] In some embodiments, the interior header member 10 may have a cross-sectional diameter that is less than the cross sectional of the exterior header member so as to form or otherwise define a lip 20. As is shown in
[0051] As discussed below, the diaphragm 150 (not shown in
[0052] In an example embodiment, such as shown in
[0053] Referring now to
[0054] As shown in
[0055] In some embodiments, the diameter of the header opening at the second end 35 is less than the cross-sectional diameter DE of the exterior header member 15 and the diameter of the header opening at the second end 35 is greater than the cross-sectional diameter Di of the interior header member 10. In such examples, the diameter of the header opening at the second end 35 and the cross-sectional diameter Di of the interior header member 10 may be near identical diameter, such that the interior header member fits flush with the header opening at the second end 35, such as is shown in
[0056] In various embodiments, the pressure sensor 100 may include a processor 130 (e.g., an ASIC) mounted on the header 110, such mounting may be a direct mounting to the interior header member 10 of the header 110 or may be an indirect mounting mounted to the header 110 (e.g., mounted to a ceramic plate, a printed circuit board (“PCB”), or a glass plate that is mounted to the header 110) via adhesive. In some examples, the adhesive may have a sufficient bond line thickness so as to provide, in some examples, insulation resistance.
[0057] In example embodiments, the processor may take the form of an ASIC made of silicon and, thus, may include amplification (e.g., an operational amplifier (“op-amp”)), analog-to-digital conversion (“ADC”), offset compensation circuitry, erasable programmable read-only memory (“EPROM”), printed circuit board assembly (“PCBA”), and/or other suitable signal conditioning electronics. As discussed in more detail throughout, the processor 130 may receive a signal from a sensing element 140, and condition and/or process the signal for transmission from the pressure sensor 100.
[0058] In various embodiments, the pressure sensor 100 may include a sensing element 140, which may take the form of a sensing die that is made of silicon. Specifically, and in some embodiments, the sensing element 140 may be a deep reactive-ion etched (DRIE) sensing die. In some embodiments, the sensing element 140 may include an etched cavity that defines at least part of the pressure sensing diaphragm on a first or back side. In some embodiments, the second or front side of the sensing element 140 may also include one or more bond pads so as to allow for a connection with the processor 130.
[0059] In some embodiments, the sensing element 140 may be directly attached on the processor 130 in a stacked relationship, as is shown in
[0060] In some embodiments, the sensing element 140 may be a micromechanical sensor element fabricated using a silicon wafer and suitable fabrication techniques. The sensing element 140 may have one or more pressure sensing circuitry (e.g., trim circuitry, signal conditioning circuitry, etc.) formed using any suitable fabrication or printing techniques. In some cases, the sensing element 140 may include a pressure sensing diaphragm including one or more sensing components, such as piezoresistive sensing components, formed thereon for sensing a deflection and thus a pressure differential between a top and bottom side of the pressure sensing diaphragm. In some embodiments, the pressure sensing diaphragm may be fabricated by back-side etching a silicon die, however, it is contemplated that any other suitable process may be used, as desired.
[0061] When provided, the piezoresistive components may be configured to have an electrical resistance that varies according to an applied mechanical stress (e.g., pressure sensing diaphragm deflection). In some cases, the piezoresistive components may include a silicon piezoresistive material, however, other non-silicon materials may be used. In some cases, the piezoresistive components may be connected in a Wheatstone bridge configuration (full or half bridge). It is to be understood that the piezoresistive components are only one example of a pressure sensing element that can be used, and it is contemplated that any other suitable sensing elements may be used, as desired.
[0062] In an example embodiment, the pressure sensor housing 120, the diaphragm 150, and the header 110 together define a component compartment 180 that may be hermetically sealed (“hermetically sealed component compartment”). The hermetically sealed component compartment 180 may be filled with a reference fluid that the pressure sensor may use to determine the fluid pressure of the exterior fluid. For example, the hermetically sealed component compartment 180 may be incompressible oil filled, such as with silicone oil. As is shown in
[0063] As is shown in
[0064] In an example embodiment, the processor 130 and the sensing element 140 may be in communication through one or more wires (e.g., bond wires). Moreover, the processor 130 may be connected to at least one of the three or more header pins 105 by three or more wires (e.g., bond wires). In such an embodiment, the processor 130 may transmit and/or receive electrical signals from outside of the hermetically sealed component compartment 180 through the at least one of the three or more header pins 105. For example, the header pin 105 may be in contact with a printed circuit board (PCB) 610, such as the PCB shown in
[0065] In an example embodiment, the diaphragm 150 may have a first surface 40 and a second surface 45. In some instances, the diaphragm 150 may take the form of a thin, solid material, such as stainless steel, that is configured to provide media isolation between the fluid being measured and the sensing element 140. In an example embodiments, the diaphragm 150 may be attached to the pressure sensor housing 120 at the first end 30 of the pressure sensor housing. The diaphragm 150 may be bonded to the pressure sensor housing 120 using welding, a seal, a gasket, or any other suitable bonding or sealing mechanism (e.g., solder, eutectic, etc.). The diaphragm 150 may be configured such that it deflects based on a difference in pressure between fluid in contact with the first surface 40 of the diaphragm and the second surface 45 of the diaphragm.
[0066] In an example embodiment and in operation, a fluid to be measured will be introduced to the first surface 40 of the diaphragm 150 and the difference in pressure between the fluid on the first surface 40 and the fluid in the hermetically sealed component compartment 180 (e.g., the fluid on the second surface 45 of the diaphragm) may cause the diaphragm to deflect in one direction (e.g., if the pressure of the fluid is higher than the component compartment fluid, then the diaphragm 150 may deflect towards the component compartment 180 direction). In such an embodiment, the deflection of the diaphragm 150 causes the pressure of the fluid in the component compartment 180 to change and the altered pressure of the component compartment fluid is measured by the sensing element 140. The measurement by the sensing element 140 is transmitted to the processor 130, where the processor determines the pressure of the fluid to be measured based on the original pressure of the component compartment fluid and the altered pressure of the component compartment fluid.
[0067] In an example embodiment, as shown in
[0068] In an example embodiment, the protective cap 170 may be configured to provide a fluid passageway, similar to the fluid inlet 1060 in
[0069] As shown in
[0070] Referring now to
[0071] Referring now to
[0072]
[0073] Referring now to
[0074] Referring now to
[0075] As discussed in more detail in relation to
[0076]
[0077] Referring now to
[0078] In some embodiments, such as shown in
[0079] Referring now to
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[0081] The application of the pressure sensor may determine the level of attachment in some examples. In some embodiments, various attachment methods may be used for the top plate 1005 and base plate 1000, such as screws, adhesive, welding, and the like. The type of attachment may be based on the expected access needed for the pressure sensor 100. For example, a top plate 1005 may be screwed to the base plate 1000 such that the top plate may be removed quickly to access or replace the pressure sensor 100. In some embodiments, the top plate 1005 may be screwed by one or more screws to the base plate 1000. For example, as shown in
[0082] In some embodiments, the base plate 1000 may have a pressure sensor recess 1050 defined to allow at least a portion of the pressure sensor 100 to be positioned. For example, as shown in
[0083] In an example embodiment, the top plate 1005 may engage with the pressure sensor housing 120 to hold the pressure sensor 100 in place. In some embodiments, the top plate 1005 may define a pressure sensor cutout 1070 that is larger than the portion of the pressure sensor 100 that is not positioned in the pressure sensor recess 1050 of the base plate 1000. For example, the pressure sensor cutout 1070 may have the same cross-sectional shape as the pressure sensor (e.g., circular) and have a diameter greater than the second end 35 of the pressure sensor housing 120. In some embodiments, the pressure sensor cutout 1070 may have a smaller cross-sectional diameter than the first end 30 of the pressure sensor, as shown, such that the pressure sensor cutout 1070 of the top plate 1005 engages with the pressure sensor housing 120 and prevents vertical movement. In an example embodiment, the overhang of the pressure sensor cutout 1070 may extend around the entire pressure sensor housing 120, as shown. The top plate 1005 may be a thickness that allows the support plate 600 to be placed in contact with the header pins 105, such as shown in
[0084] Referring now to
[0085] In some embodiments, one or more of the pressure sensors 100 may determine the pressure of the same or different fluids. For example, there may be multiple different fluid pressures that are monitored in a system and the fluid inlets 1060 may be configured to allow multiple different compartments that have different fluids to be measured (e.g., a pressure sensor may determine the pressure of water in an engine and another pressure sensor may determine the pressure of oil in the same engine).
[0086] In some embodiments, two or more pressure sensors may determine the pressure of the same fluid. For example, there may be some pressures that are critical, in some examples, for operation and therefore a redundant pressure sensor may be implemented to reduce the possibility of inaccurate pressure readings. In such a case, some of the fluid inlets 1060 for each of the two or more pressure sensors 100 may be connected to the same reservoir. In some embodiments, as shown in
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[0088] Referring now to
[0089] Referring now to Block 1410 of
[0090] Referring to Block 1420 of
[0091] Referring now to Block 1430 of
[0092] Referring now to
[0093] Referring now to Block 1510 of
[0094] Referring now to Block 1520 of
[0095] Referring now to Block 1530 of
[0096] Referring now to Block 1540 of
[0097] In some embodiments, certain ones of the operations, shown in
[0098] Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe example embodiments in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.