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US 2002/0162956 A1Published application
Diffractive optical fluid shear stress sensor
AssigneeCalifornia Institute of Technology
InventorsMorteza Gharib, Daniel W. Wilson, Siamak Forouhar, Richard E. Muller, Dominique Fourguette, Darius Modarress, Frederic Taugwalder
Life of this patent
Estimating the term…
Abstract
A diffractive optic sheer stress sensor operates by forming diverging fringes over a linear area of measurement. A diode laser focuses light onto a diffractive lens which focuses the light to respective slits. The slits form diverging fringes, and scattered light from the fringes is collected by a window and focused by another diffractive lens to a receiver.
Claims53
An assembly, comprising:
- a source of illumination;
- an illumination converting element, which focuses said illumination to first and second foci;
- first and second slits adjacent said first and second foci, and placed to cause said illumination to emit from said first and second slits and interfere to form linearly diverging fringes over a measurement area;
- and
- a light collecting part, collecting light which is scattered from particles in said measurement area to determine information about said particles in said measurement area.
2 more elements
A sensor, comprising:
- an optical substrate, having first and second opposite surfaces, a first surface formed with first and second diffractive lenses thereon, and a second surface formed with an optical mask having holes therein;
- said first diffractive lens providing a collimation to two separate locations,
- said optical mask having slits therein at said two separate locations of a type which are effective to create linearly diverging fringes over a measurement area;
- said optical mask also including a window at a location which is spaced from said two separate locations, to receive light that is scattered from said measurement area,
- said second diffractive lens spaced from said first diffractive lens in the same direction that said window is spaced from said slits, said second diffractive lens being operative to receive and collimate said scattered light from said window.
2 more elements
A sensor, comprising:
- an optical substrate, having a first area with a first optical element and a plurality of slits which in combination with said first optical element forms linearly diverging fringes over a measurement area, and having a second area with a receiving window for scattered light from said measurement area and a second optical element receiving said scattered light from said receiving window, said optical substrate including an optical isolator which isolates between said first area and said second area.
A sheer stress sensor, comprising:
- an optical substrate, having a first area with a first optical element and a plurality of slits which in combination with said first optical element forms linearly diverging fringes over a measurement area, where an entire area of said first optical element couples light to each of said plurality of slits, and having a second area with a receiving window for scattered light from said measurement area and a second optical element receiving said scattered light from said receiving window.
A shear stress sensor, comprising:
- an optical substrate, having a first area with a first optical element and a plurality of slits which in combination with said first optical element forms linearly diverging fringes over a measurement area, and having a second area with a receiving window receiving scattered light from two different locations in said measurement area and second and third optical elements receiving said scattered light from said respective two different locations.
Dependencies are inferred from the claim text.