Pressure sensor apparatus

• US 6,487,911 B1
• Filed: 11/21/2000
• Issued: 12/03/2002
• Est. Priority Date: 11/21/2000
• Status: Expired due to Term

• Current Assignee: Sensata Technologies Incorporated (Sensata Technologies Holding Plc), Stanley J. Lukasiewicz
• Original Assignee: Texas Instruments, Inc.
• Inventors: Frackelton, Peter H., Lukasiewicz, Stanley J.
• Primary Examiner(s): Fuller, Benjamin R.
• Assistant Examiner(s): ALLEN, ANDRE J
• Application Number:
  US09/717,763
• Time in Patent Office: 742 Days
• Field of Search: 737/00, 737/15, 737/06, 737/14, 737/16, 737/17, 737/18, 737/24, 737/56, 737/36, 361/283.1, 361/283.2, 361/283.3, 361/283.4, 174/50, 455/90
• US Class Current: 73/718
• CPC Class Codes: G01L 19/14 Housings G01L19/0007, G01L19/0084, G01L19/0092, G01L19/04, G01L19/06 take precedence
• CPC Class Codes: G01L 9/0075 using a ceramic diaphragm, e.g. alumina, fused quartz, glass

Abstract

A fluid pressure sensor (10) has a generally polyhedron configured capacitive transducer (18) electrically connected to a flexible circuit using interference fit U-shaped edge connectors (20). The flexible circuit (16) is received in an electronics chamber formed in a top end of a base member (12) with the corners of the transducer disposed on the face surface (12f) of the top. A cover (24) is formed with a circular fluid pressure opening (24a) through which a sealing gasket (22) extends, the gasket having tabs (22a) received in a seat (24c) formed in the bottom surface of the top wall (24b) of the cover. A transducer receiving seat (24d) is also formed in the bottom surface of the cover for placement of transducer (18). The cover is formed with opposing legs (24h) which interfit with notches (12d) in the base and a third leg (24n) slidingly received in a slot formed in the base through which conductive tails (16h) of the flexible circuit (16) extend for electrical engagement with a hexport (26) slidingly received over the cover and top portion of the base member.

Claims

1. A fluid pressure sensor comprising

a base assembly having a base member having a bottom wall and an upstanding sidewall defining an electronics chamber and a plurality of elongated terminals, the base member mounting the plurality of elongated terminals in spaced apart relation extending through the base wall into the electronics chamber, a flexible circuit having a substrate formed with first and second lobe portions with an intermediate portion therebetween, the flexible circuit being bent into a generally U-shaped configuration having an inner surface for mounting electronic components and an outer surface with the first lobe portion formed with terminal receiving holes through which respective elongated terminal members extend,

a capacitive fluid pressure sensing element shaped generally as a polyhedron having a substrate side and a pressure sensing side with terminal pads on the pressure sensing side thereof, the second lobe portion of the flexible circuit having an end portion bent generally perpendicular relative to the remainder of the second lobe portion in a direction away from the first lobe portion with the flexible circuit in the U-shaped configuration, and formed with terminal pads thereon, the capacitive pressure sensing element received on the outer surface of the second lobe portion engaging the bent end thereof, electrically conductive, generally U-shaped edge clips having first and second legs, the first legs engaging respective terminal pads on the inner surface of the second lobe portion and the second legs engaging respective terminal pads on the pressure sensing side of the capacitive pressure sensing element, outer peripheral portions of the substrate side of the capacitive pressure sensing element received on a top surface portion of the base member sidewall,

a cover member received over the capacitive pressure sensing element on the top surface of the base member, the cover member having a fluid pressure receiving opening therethrough, and

a flexible annular gasket disposed between the cover member and the capacitive pressure sensing element, and

a fluid coupling member attached to the base member.

3. A fluid pressure sensor according to claim 1 in which the capacitive fluid pressure sensing element comprises a relatively thick substrate having a top surface and a relatively thin diaphragm having a bottom surface attached to the substrate with the top surface of the substrate facing the bottom surface of the diaphragm, the substrate extending in one direction beyond the diaphragm exposing the top surface of the substrate and the terminal pads are located on the extended, exposed portions of the top surface of the substrate.

4. A fluid pressure sensor according to claim 1 in which first and second opposed notches are formed in the upstanding sidewall of the base member and the cover is formed with first and second legs, each leg having a free distal end formed with a lip, the lip of each leg being received in a respective notch in the upstanding sidewall to attach the cover to the base member.

5. A fluid pressure sensor according to claim 4 in which a slot is formed in the upstanding sidewall and the flexible circuit is formed with at least one conductive tail which is received through the slot extending beyond the base member and the fluid coupling member is formed of electrically conductive material and is received around the upstanding sidewall and in engagement with the conductive tail.

6. A fluid pressure sensor according to claim 5 in which the cover is formed with a third leg which is slidably received in the slot, the third leg having a distal end which is closely adjacent to the at least one conductive tail.

7. A fluid pressure sensor according to claim 1 in which the capacitive pressure sensing element has a plurality of corners and outer peripheral portions of the substrate side of the capacitive pressure sensing element received on the said a top surface portion of the base sidewall comprises at least some of the four corners.

9. A fluid pressure sensor according to claim 7 in which the capacitive fluid pressure sensing element comprises a relatively thick substrate having a top surface and a relatively thin diaphragm having a bottom surface attached to the substrate with the top surface of the substrate facing the bottom surface of the diaphragm, the substrate extending in one direction beyond the diaphragm exposing the top surface of the substrate and the terminal pads are located on the extended, exposed portions of the top surface of the substrate.

10. A fluid pressure sensor according to claim 7 in which the base has an upstanding sidewall and first and second opposed notches are formed in the upstanding sidewall of the base member and further comprising a cover received on the base over the capacitive fluid pressure sensing element, the cover being formed with first and second legs, each leg having a free distal end formed with a lip, the lip of each leg received in a respective notch in the upstanding sidewall to attach the cover to the base member.

11. A fluid pressure sensor according to claim 9 further comprising an electrically conductive fluid coupling members and in which a slot is formed in the upstanding sidewall and the flexible circuit is formed with at least one conductive tail which is received through the slot extending beyond the base member and the fluid coupling member is received around the upstanding sidewall and in engagement with the conductive tail.

12. A fluid pressure sensor according to claim 10 in which the cover is formed with a third leg which is slidably received in the slot, the third leg having a distal end which is closely adjacent to the at least one conductive tail.

2. A fluid pressure sensor comprising

a generally cylindrical base assembly having a base member formed with a bottom wall and an upstanding generally circular sidewall defining an electronic chamber, a plurality of elongated terminals, the base member mounting the plurality of elongated terminals in spaced apart relation and extending through the bottom wall into the electronics chamber,

signal conditioning electronics disposed in the electronics chamber electrically connected to the elongated terminals,

a generally circular cover member received on the upstanding sidewall of the base member, the cover member having a top wall formed with a generally circular fluid pressure receiving opening therethrough, a first gasket seat formed in the bottom surface of the top wall having a plurality of spaced apart tab receiving surfaces, a second generally rectangular pressure sensor seat formed in the bottom surface of the top wall and aligned with the first gasket seat,

an annular flexible gasket received through the circular opening of the cover member, the gasket having radially outwardly extending tabs, each tab received on a respective tab receiving surface,

a capacitive fluid pressure sensing element having a generally rectangular periphery received on the second pressure sensor seat, the capacitive fluid pressure sensing element being electrically connected to the signal conditioning electronics, and

a fluid coupling member attached to the base member.

8. A fluid pressure sensor comprising

a flexible circuit having a substrate with an end portion bent generally perpendicular relative to an adjacent portion of the substrate and having terminal pads formed on the substrate,

a capacitive fluid pressure sensing element having other terminal pads thereon, the sensor element received on the flexible circuit engaging the bent end portion thereof,

generally U-shaped edge clips having first and second legs, the first legs biased into engagement with respective terminal pads on the flexible circuit and the second legs biased into engagement with respective terminal pads on the capacitive fluid pressure sensing element,

a base, the capacitive fluid sensing element mounted on the base and a plurality of elongated terminals mounted on the base in spaced apart relation and electrically connected to the flexible circuit.

13. A condition responsive sensor comprising

a flexible circuit having a substrate with an end portion bent generally perpendicular thereto and having terminal pads formed on the substrate,

a condition responsive sensor element having terminal pads thereon,

the condition responsive sensor element engaging the bent end portion,

generally U-shaped edge clips having first and second legs, the first legs biased into engagement with respective terminal pads on the flexible circuit and the second legs biased into engagement with respective terminal pads on the condition responsive element,

a base, the condition responsive sensor element mounted on the base and elongated terminals mounted on the base in spaced apart relation and generally connected to the flexible circuit.