Absolute pressure sensor
First Claim
Patent Images
1. An absolute pressure sensor, comprising:
- a base layer surrounding a passageway between an inlet adapted to receive a pressure and a mounting face on the base layer;
a sensor layer having a first face bonded by an insulating bond to the mounting face, the sensor layer including a conductive diaphragm aligned with the passageway, forming a pressure cavity that is between the sensor layer and the base layer, the pressure cavity receiving the pressure; and
a reference layer mounted on the sensor layer to form a reference vacuum cavity that is aligned with the conductive diaphragm, the reference layer including a conducting surface facing the conductive diaphragm across the reference vacuum cavity to form a pressure sensing capacitor, the conductive diaphragm separating the reference vacuum cavity from the pressure cavity, the conductive diaphragm sensing absolute pressure.
1 Assignment
0 Petitions
Accused Products
Abstract
A barometric pressure sensor including a base layer, a sensor layer and a reference layer. The base layer has a passageway between a pressure inlet and a mounting face. The sensor layer is bonded by an insulating bond to the mounting face and includes a conductive diaphragm. The reference layer is mounted on the sensor layer to form a reference vacuum cavity. The reference layer includes a conducting surface facing the conductive diaphragm across the reference vacuum cavity to form a pressure sensing capacitor.
59 Citations
25 Claims
-
1. An absolute pressure sensor, comprising:
-
a base layer surrounding a passageway between an inlet adapted to receive a pressure and a mounting face on the base layer;
a sensor layer having a first face bonded by an insulating bond to the mounting face, the sensor layer including a conductive diaphragm aligned with the passageway, forming a pressure cavity that is between the sensor layer and the base layer, the pressure cavity receiving the pressure; and
a reference layer mounted on the sensor layer to form a reference vacuum cavity that is aligned with the conductive diaphragm, the reference layer including a conducting surface facing the conductive diaphragm across the reference vacuum cavity to form a pressure sensing capacitor, the conductive diaphragm separating the reference vacuum cavity from the pressure cavity, the conductive diaphragm sensing absolute pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. A gage pressure transmitter that includes a barometric pressure sensor, the barometric pressure sensor comprising:
-
a base layer surrounding a passageway between an inlet adapted to receive a pressure and a mounting face on the base layer;
a sensor layer having a first face bonded by an insulating bond to the mounting face, the sensor layer including a conductive diaphragm aligned with the passageway, forming a pressure cavity that is between the sensor layer and the base layer, the pressure cavity receiving the pressure; and
a reference layer mounted on the sensor layer to form a reference vacuum cavity that is aligned with the conductive diaphragm, the reference layer including a conducting surface facing the conductive diaphragm across the reference vacuum cavity to form a pressure sensing capacitor, the conductive diaphragm separating the reference vacuum cavity from the pressure cavity, the conductive diaphragm sensing absolute pressure. - View Dependent Claims (21, 22, 23, 24, 25)
a transmitter housing, the transmitter housing having a barometric pressure port bonded to the inlet.
-
-
22. The gage pressure transmitter of claim 21 further comprising a porous teflon plug disposed in the barometric pressure port.
-
23. The gage pressure transmitter of claim 20, further comprising:
-
a process pressure sensor; and
a converter circuit coupled to the process pressure sensor and the barometric pressure sensor, the converter circuit calculating a difference between process pressure and barometric pressure.
-
-
24. The gage pressure transmitter of claim 23 wherein the converter circuit includes a sigma delta analog to digital converter.
-
25. The gage pressure transmitter of claim 23 wherein the converter circuit compensates a reading from the process pressure sensor and compensates a reading from the barometric pressure sensor and calculates the difference by subtracting the compensated barometric pressure reading from the process pressure reading.
Specification