Flexible, self-rolled superficial flow sensor
A superficial flow sensor is provided, which may comprise a substrate, and a thin film comprising a self-rolled portion, a stationary portion, and a free ribbon portion. According to some aspects of the present disclosure, the self-rolled portion may be configured to have a residual stress and to deform under external forces.
1. A superficial flow sensor, comprising:
a thin film comprising a self-rolled portion, a stationary portion, and a free ribbon portion, wherein the self-rolled portion is configured to have a residual stress and to deform under external forces; and
a substrate,
wherein the self-rolled portion comprises:
a first polyimide layer;
a metal layer disposed on the first polyimide layer;
a second polyimide layer disposed on the metal layer;
a sensor layer comprising a strain gauge circuit disposed on the second polyimide layer; and
a third polyimide layer disposed on the sensor layer.
2. The sensor of claim 1 , wherein the substrate includes silicon.
3. The sensor of claim 1 , further comprising:
at least one contact pad configured to connect to a signal amplifier circuit,
wherein said strain gauge circuit being configured to sense deformation of the self-rolled portion of the thin film.
4. The sensor of claim 3 , wherein the output voltage of the strain gauge circuit is linear with respect to an external flow speed.
5. The sensor of claim 1 , further comprising:
a layer of porous silicon configured to bond the stationary portion to the substrate; and
a coating of silicon dioxide configured to bond the self-rolled portion to the substrate.