Microelectromechanical (MEM) viscosity sensor and method
First Claim
1. A microelectromechanical (MEM) viscosity sensor, comprising:
- a substrate;
first and second support structures on said substrate, said support structures spaced-apart;
a compliant member having first and second ends, said first and second ends affixed to said first and second support structures, respectively, such that said member is suspended between said support structures and above said substrate and can flex vertically with respect to said substrate, said member having a high density of perforations through which a fluid whose viscosity is to be sensed can flow;
a drive means arranged to apply a force to said member such that said member moves vertically with respect to said substrate; and
a sensing means arranged to sense the motion of said member in response to said force.
3 Assignments
0 Petitions
Accused Products
Abstract
A MEM viscosity sensor comprises a substrate, with first and second support structures affixed to the substrate and spaced-apart. A compliant member is affixed to the support structures such that it is suspended above and can flex vertically with respect to the substrate. The member has a high density of perforations, through which a fluid whose viscosity is to be sensed can flow. The sensor includes a drive means to apply a force to the member, and a sensing means to sense the vertical motion of the member in response to the applied force. The member'"'"'s perforations ensure that its resistance to motion will be shear in nature, and minimizes sensitivity to particulates. The substrate is also preferably perforated to further reduce non-shear forces and facilitate fluid exchange.
-
Citations
43 Claims
-
1. A microelectromechanical (MEM) viscosity sensor, comprising:
-
a substrate;
first and second support structures on said substrate, said support structures spaced-apart;
a compliant member having first and second ends, said first and second ends affixed to said first and second support structures, respectively, such that said member is suspended between said support structures and above said substrate and can flex vertically with respect to said substrate, said member having a high density of perforations through which a fluid whose viscosity is to be sensed can flow;
a drive means arranged to apply a force to said member such that said member moves vertically with respect to said substrate; and
a sensing means arranged to sense the motion of said member in response to said force. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
-
-
22. A microelectromechanical (MEM) viscosity sensor, comprising:
-
a substrate;
first and second support structures on said substrate, said support structures spaced-apart;
a compliant member having first and second ends, said first and second ends affixed to said first and second support structures, respectively, such that said member is suspended between said support structures and above said substrate and can flex vertically with respect to said substrate, said member and the portion of said substrate beneath said member each having a high density of perforations through which a fluid whose viscosity is to be sensed can flow and such that said compliant member is subjected to a predominately shear force when moving through said fluid;
an electrostatic drive means arranged to apply a force to said member such that said member moves vertically with respect to said substrate; and
a capacitive sensing means arranged to sense the motion of said member in response to said force. - View Dependent Claims (23)
-
-
24. A microelectromechanical (MEM) viscosity sensor, comprising:
-
a semiconductor wafer; and
a substrate bonded to said wafer and thereby forming a composite structure, portions of said composite structure patterned and etched to form;
first and second support structures on said substrate, said support structures spaced-apart; and
a compliant member having first and second ends, said first and second ends affixed to said first and second support structures, respectively, such that said member is suspended between said support structures and above said substrate and can flex vertically with respect to said substrate, said member having a high density of perforations through which a fluid whose viscosity is to be sensed can flow;
a drive means for displacing said compliant member vertically relative to said substrate; and
a sensing means arranged to sense the motion of said member in response to said force. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32)
-
-
33. A method of measuring the viscosity of a fluid, comprising:
-
providing a microelectromechanical (MEM) viscosity sensor, comprising;
a substrate;
first and second support structures on said substrate, said support structures spaced-apart;
a compliant member having first and second ends, said first and second ends affixed to said first and second support structures, respectively, such that said member is suspended between said support structures and above said substrate and can flex vertically with respect to said substrate, said member having a high density of perforations through which a fluid whose viscosity is to be sensed can flow;
a drive means arranged to apply a force to said member such that said member moves vertically with respect to said substrate; and
a sensing means arranged to sense the motion of said member in response to said force;
immersing said sensor in said fluid;
operating said drive means such that said force is applied to said compliant member as a step input; and
measuring the time response of said compliant member using said sensing means. - View Dependent Claims (34, 35)
-
-
36. A method of fabricating a microelectromechanical (MEM) viscosity sensor, comprising:
-
providing a semiconductor wafer;
providing a substrate;
forming first and second support structures on said substrate, said support structures spaced-apart; and
bonding said wafer and substrate together to form a composite structure; and
patterning and etching portions of said composite structure to form a compliant member having first and second ends, said first and second ends affixed to said first and second support structures, respectively, such that said member is suspended between said support structures and above said substrate and can flex vertically with respect to said substrate, said member having a high density of perforations through which a fluid whose viscosity is to be sensed can flow. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43)
-
Specification