Oil filled gage reference side protection

Patent metadata

Field	Value
Publication number	US-10247632-B2
Application number	US-201615191074-A
Country	US
Kind code	B2
Filing date	Jun 23, 2016
Priority date	Jun 23, 2016
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A pressure sensor can include a housing having a sense side cavity formed on a first side of the housing; a sense side diaphragm attached to the first side and over the sense side cavity, a sense die assembly placed in the cavity and attached to the housing; a reference side cavity formed in the housing, a reference side diaphragm attached to a second side of the housing and over the reference side cavity, and pin(s) electrically connected to the sense die assembly and extending outside the housing from the second side. The cavities are filled with oil. Manufacturing the pressure sensor can include mounting the sense die assembly onto the housing, attaching the sense side diaphragm to the first side of the housing, filling the cavities with oil, and attaching the reference side diaphragm on the second side of the housing and over the reference side cavity.

First claim

What is claimed is:

1. A pressure sensor comprising:
a housing having a sense side cavity formed on a first side of the housing;
a sense side diaphragm attached to the first side of the housing and over the sense side cavity, wherein the sense side diaphragm has a first surface area exposed to the sense side cavity;
a sense die assembly placed in the sense side cavity and attached to the housing, wherein the sense die assembly comprises a sense die having a front side exposed to at least a portion of the sense side cavity;
a reference side cavity formed in the housing, wherein a back side of the sense die of the sense die assembly is exposed to the reference side cavity;
a reference side diaphragm attached to a second side of the housing and over the reference side cavity, wherein the reference side diaphragm has a second surface area exposed to the reference side cavity that is less than one-half that of the first surface area, and wherein the reference side diaphragm deflects in response to variation(s) in atmospheric pressure so as to provide a reference side pressure to the reference side cavity;
one or more pins each spaced laterally outside a perimeter of the reference side diaphragm but inside a perimeter of the sense side diaphragm, the one or more pins electrically connected to the sense die assembly and extending outside the housing from the second side; and
wherein the sense side cavity and the reference side cavity are filled with oil.

2. The pressure sensor of claim 1 , further comprising:
a fill channel extending between the sense side cavity and the second side of the housing.

3. The pressure sensor of claim 2 , further comprising:
a seal placed over the fill channel on the second side of the housing.

4. The pressure sensor of claim 3 , wherein the seal is a ball seal welded to the second side of the housing over the fill channel.

5. The pressure sensor of claim 1 , wherein the sense side diaphragm has a circular shape and the reference side diaphragm has a circular shape, wherein a diameter of the reference side diaphragm is less than one-half that of a diameter of the sense side diaphragm.

6. The pressure sensor of claim 1 , wherein the reference side diaphragm is attached to the second side of the housing via at least one projection weld.

7. The pressure sensor of claim 1 , wherein a weld ring is used to attach the reference side diaphragm to the second side of the housing.

8. The pressure sensor of claim 1 , the sense die assembly further comprising:
a die attach which attaches the sense die assembly to the housing.

9. The pressure sensor of claim 8 , wherein the die attach comprises a conductive or non-conductive adhesive.

10. The pressure sensor of claim 1 , wherein:
the reference side diaphragm comprises a lip portion and a deflecting portion, wherein the lip portion is attached to the second side of the housing, and wherein the deflecting portion has a contour such that a space is formed between the second side of the housing and the deflecting portion.

11. A pressure sensor comprising:
a housing having a sense side cavity formed on a first side of the housing;
a sense side diaphragm attached to the first side of the housing and over the sense side cavity, the sense side diaphragm having a first surface area exposed to the sense side cavity;
a sense die assembly placed in the sense side cavity and attached to the housing, wherein the sense die assembly comprises a sense die having a front side exposed to at least a portion of the sense side cavity;
a reference side cavity formed in the housing, wherein a back side of the sense die of the sense die assembly is exposed to the reference side cavity;
a reference side diaphragm attached to a second side of the housing and over the reference side cavity, wherein the reference side diaphragm has a second surface area exposed to the reference side cavity that is less than one-half that of the first surface area;
one or more pins each spaced laterally outside a perimeter of the reference side diaphragm but inside a perimeter of the sense side diaphragm, the one or more pins electrically connected to the sense die assembly and extending outside the housing from the second side and
wherein the sense side cavity and the reference side cavity are filled with oil.

12. A method of manufacturing a pressure sensor, the method comprising:
mounting a sense die assembly onto a housing such that a front side of a sense die of the sense die assembly is exposed to a sense side cavity formed in a first side of the housing and a back side of the sense die of the sense die assembly is exposed to a reference side cavity formed in a second side of the housing and such that the sense die assembly is electrically connected to one or more pins which extend outside the housing;
filling the sense side cavity and the reference side cavity with oil by submerging the assembly in an oil bath;
welding a sense side diaphragm to the first side of the housing while submerged in the oil bath, the sense side diaphragm having a first surface area exposed to the sense side cavity;
welding a reference side diaphragm on the second side of the housing and over the reference side cavity while submerged in the oil bath, wherein the reference side diaphragm has a second surface area exposed to the reference side cavity that is less than one-half that of the first surface area, and wherein the reference side diaphragm deflects in response to variation(s) in atmospheric pressure so as to apply an atmospheric pressure to the reference side cavity and thus the back side of the sense die of the sense die assembly; and
wherein the step of welding the sense side diaphragm and the step of welding the reference side diaphragm are performed simultaneously while submerged in the oil bath.

13. The method of claim 12 , further comprising:
attaching a seal on the second side of the housing and over a fill channel which extends between the sense side cavity and the second side of the housing while submerged in the oil bath.

14. The method of claim 13 , wherein the step of attaching the reference side diaphragm and the step of attaching the seal are performed simultaneously or in series during a single phase of manufacturing the pressure sensor.

15. The method of claim 13 , wherein the seal is a ball seal.

16. The method of claim 12 , further comprising:
using a weld ring to attach the reference side diaphragm to the second side of the housing.

17. The method of claim 12 , further comprising:
forming a recessed portion on the second side of the housing, wherein the reference side diaphragm extends over the recessed portion such that a space is present between the recessed portion and the reference side diaphragm.

18. The method of claim 12 , wherein the sense die assembly is mounted to the housing with a die attach comprising a conductive or non-conductive adhesive.

19. The method of claim 12 , further comprising:
placing one or more filler elements in the sense side cavity before filling the sense side cavity with oil.

20. The method of claim 12 , wherein the reference side diaphragm comprises a lip portion and a deflecting portion, wherein the lip portion is attached to the second side of the housing, and wherein the deflecting portion has a contour such that a space is formed between the second side of the housing and the deflecting portion.

Assignees

• Honeywell Int Inc
• Honeywell Int

Inventors

• Jones Ryan
• Bradley Alistair David
• Eckhardt Todd

Classifications

• G01L19/147 Primary

  Details about the mounting of the sensor to support or covering means · CPC title