Abstract: A method of making a deflectable, free hanging micro structure having at least one hinge member, the method includes the steps of providing a first sacrificial wafer having a single crystalline material constituting material forming the micro structure. A second semiconductor wafer including necessary components for forming the structure in cooperation with the first wafer is provided. Finite areas of a structured bonding material is provided, on one or both of the wafers at selected locations, the finite areas defining points of connection for joining the wafers. The wafers are bonded using heat and optionally pressure. Sacrificial material is etched away from the sacrificial wafer, patterning the top wafer by lithography is performed to define the desired deflectable microstructures having hinges, and subsequently silicon etch to make the structures.

Abstract: A fluid flow sensor uses lift forces exerted on a plate-like airfoil member to determine the velocity of a fluid flowing past the sensor. The member has a pair of spaced, low aspect ratio airfoil elements. A central portion of the airfoil member is coupled to a frame that positions the airfoil member in the fluid flow with an angle of attack with respect to the fluid flow direction. The flowing fluid generates velocity related lift forces on the airfoil member, the magnitude of which decrease along the airfoil member from the upstream end to the downstream end. The lift forces so applied deflect the upstream airfoil element to a greater extent than the downstream airfoil element. Strain gauges are coupled to the airfoil elements to detect their deflection. The strain gauges are connected in a bridge configuration to provide a signal indicative of fluid velocity.