Low profile shear-sensing unit
AssigneeThe Regents of the University of California
InventorsChang-Jin Kim, Muchen Xu
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Abstract
A low-profile shear-sensing unit includes a floating plate surrounded by a frame and a displacement sensor that measures in-plane movement of the floating plate. Covered with a surface sample, the floating plate is displaced by the friction drag (i.e., shear) on the surface caused by the flow of fluid and the in-plane displacement is measured by the displacement sensor. The shear force on the sample surface is then obtained by multiplying the measured displacement and the spring constant of the flexure beams, which suspend the floating plate. The floating plate and the flexure beams are formed out of one plate or substrate to achieve monolithic construction with a beam geometry that leads to a high-resolution measurement.
Claims21
A shear-sensing unit comprising:
- a frame plate;
- a floating plate disposed inside the frame plate in substantially the same plane with the frame plate and secured to the frame plate only via a plurality of flexure beams disposed in substantially the same plane with the frame plate, the floating plate being free of any actuator imparting force to the floating plate against the frame plate and having a sample supporting surface and a back surface;
- a ruler secured to or formed on the back surface of the floating plate;
- a displacement sensor configured to sense in-plane movement of the ruler;
- and
- wherein the plurality of flexure beams are shaped to deform in a direction along a plane of the floating plate and wherein each of the plurality of flexure beams has a width smaller than 1 mm, a thickness larger than the width, and total length at least fifty (50) times larger than the width.
Dependencies are inferred from the claim text.