Mechanical stabilizing and electrical as well as hydraulic adapting of a silicon chip by ceramics

Patent metadata

Field	Value
Publication number	US-9689768-B2
Application number	US-201314652959-A
Country	US
Kind code	B2
Filing date	Dec 6, 2013
Priority date	Dec 21, 2012
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A pressure difference sensor includes a pressure difference measuring cell, which has a measuring cell platform with pressure contactable measuring chambers in its interior, a first mounting surface and a second mounting surface. The mounting surfaces have a variable separation under pressure loading of the measuring chambers. A first reinforcement element with a first planar reinforcement area and a second reinforcement element with a second planar reinforcement area. A deflection of the mounting surfaces due to a pressure loading of the measuring chambers is lessened by the reinforcement elements, wherein especially at least 50% of an effective stiffness K=1/(dx/dp) of the reinforcement elements connected by the pressure difference measuring cell is provided only by these connections of the reinforcement element with the measuring cell platform without additional connections between the reinforcement elements in a parallel branch, wherein x is the separation between the first mounting surface and the second mounting surface having the greatest pressure dependence dx/dp.

First claim

The invention claimed is:

1. A pressure difference sensor, comprising:
a pressure difference measuring cell, which has a measuring cell platform having a first measuring chamber and a second measuring chamber in its interior,
said measuring chambers are separated from one another by a measuring membrane,
said measuring cell platform has on a first measuring chamber side a first planar mounting surface facing away from the measuring membrane, and on a second measuring chamber side a second planar mounting surface facing away from the measuring membrane,
said measuring chambers have, in each case, a measuring chamber opening to the first, respectively second, planar mounting surface, via which they are contactable with a first, respectively second, pressure,
said measuring membrane is elastically deformable as a function of a difference between the first pressure in said first measuring chamber and the second pressure in said second measuring chamber;
a transducer for providing a signal dependent on the deformation of said measuring membrane;
a first reinforcement element having a first planar reinforcement area, wherein there extends through said first planar reinforcement element a first pressure duct, which opens into the first reinforcement area and communicates with the first measuring chamber opening, said first reinforcement area is connected pressure bearingly with said first mounting surface; and
a second reinforcement element having a second planar reinforcement area, wherein there extends through said second planar reinforcement element a second pressure duct, which opens into said second reinforcement area and communicates with said second measuring chamber opening, said second reinforcement area is connected pressure bearingly with said second mounting surface, wherein:
a deflection of said first and said second mounting surfaces due to a pressure loading of said first and said second measuring chambers is lessened by said reinforcement elements to no greater than 25%, especially no greater than 10%, preferably no greater than 5%, further preferably no greater than 2% and especially preferably no greater than 1% of the deflection of said mounting surfaces of a pressure difference measuring cell of same type without connection with said reinforcement elements;
at least 50%, preferably at least 70%, further preferably at least 85% and especially preferably at least 95% of an effective stiffness K=1/(dx/dp) of said reinforcement element connected by the pressure difference measuring cell is provided only by these connections of said reinforcement element with said measuring cell platform without additional connections between said reinforcement elements in a parallel branch, wherein x is the separation between said first mounting surface and said second mounting surface having the greatest pressure dependence dx/dp.

2. The pressure difference sensor as claimed in claim 1 , wherein:
there are no additional, direct mechanical connections between said reinforcement elements contributing more than 5%, especially more than 2%, to the stiffness K.

3. The pressure difference sensor as claimed in claim 1 , further comprising:
at least one additional, direct mechanical connection between said reinforcement elements by means of a connecting body, wherein:
said connecting body has a connecting surface, which is connected with both said reinforcement elements, said connecting surface is essentially perpendicular to said mounting surfaces and said reinforcement areas.

4. The pressure difference sensor as claimed in claim 1 , wherein:
the pressure difference measuring cell comprises silicon.

5. The pressure difference sensor as claimed in claim 1 , wherein:
said reinforcement elements comprise a ceramic material, especially aluminum nitride (AIN) and silicon nitride (Si3N4), or other nitride ceramics, whose expansion coefficient is, for instance, no greater than 5 ppm/K.

6. The pressure difference sensor as claimed in claim 1 , wherein:
said reinforcement elements are joined with said measuring cell platform by means of a glass solder.

7. The pressure difference sensor as claimed in claim 1 , wherein:
said reinforcement elements have, in each case, a pressure tube connection area, which extends essentially perpendicularly to said reinforcement area; and
said pressure duct extends from the pressure tube connection area to said reinforcement area.

8. The pressure difference sensor as claimed in claim 1 , wherein:
said reinforcement elements are, in each case, connected with a pressure tube, which, in turn, is connected to a hydraulic measuring aid; and
the contribution of said pressure tubes to the effective stiffness K amounts to less than 2% of K, especially less than 1% of K and especially preferably less than 0.1% of K.

9. The pressure difference sensor as claimed in claim 8 , wherein:
said reinforcement elements are connected with said pressure tubes by means of a glass solder, a metal solder or adhesive.

10. The pressure difference sensor as claimed in claim 1 , wherein:
said reinforcement elements have at least sectionally an electrically conducting coating, via which an electrical transducer of the pressure difference measuring cell is connected with an electronic circuit.

Assignees

• Endress Hauser Gmbh Co Kg

Inventors

• Lemke Benjamin
• Teipen Rafael
• Tham Anh Tuan

Classifications

• G01L19/0618

  Overload protection · CPC title

• G01L13/025 Primary

  using diaphragms · CPC title