Device for detecting interaction with an object

Abstract

A device and method for the detection of the interaction between two or more objects is disclosed. The device utilizes electrical impedance spectra measured from a piezoelectric element attached to one such object. Comparison of such spectra along a range of traverse allows precise estimates of distance to be made. One useful application is the topographical mapping of a surface.

1 . A device for detecting the physical interaction of two or more objects comprising
 a contact object   a piezoelectric element attached to said contact object, such piezoelectric element having a measurable change in electrical properties at more than one applied alternating current frequency when the contact object interacts with another object or objects   an operable electrical connection to means for measuring the electrical properties of said piezoelectric element; and   positioning means to move said contact object into contact proximity to a target object or objects.   
     
     
         2 . The device of  claim 1 , wherein said target object is selected from the group consisting of a substantially planar object, a curved object, an object with a patterned or complex surface, and a spatially disposed object. 
     
     
         3 . The device of  claim 1  wherein the electrical properties to be measured are selected from the group consisting of impedance, resistance, capacitance, reactance, and phase. 
     
     
         4 . The device of  claim 1  wherein said physical interaction is contact between said contact object and said target object or objects. 
     
     
         5 . The device of  claim 1  wherein said contact object is selected from the group consisting of a hollow glass cylinder, a hollow glass cylinder having a tapered tip, a solid metal pin, a hollow metal cylinder having a tapered tip, a solid polymer pin, and a hollow polymer cylinder having a tapered tip or combinations thereof. 
     
     
         6 . A device for detecting the fluid level in a hollow vessel comprising
 a hollow substantially round tubular structure adapted to contain a liquid having an inner and an outer wall   a piezoelectric element attached to the said outer wall of said tubular structure, such piezoelectric element having a measurable change in electrical properties at more than one applied alternating current frequency with a change in fluid level within the vessel, and   an operable electrical connection to means for measuring the electrical properties of said element.   
     
     
         7 . The device of  claim 6  wherein said tubular structure is a capillary tapered at one end. 
     
     
         8 . A method of detecting fluid in a hollow vessel comprising
 providing a hollow substantially round tubular structure adapted to contain a liquid having an inner and an outer wall, said structure having a piezoelectric element attached to said outer wall, and an operable electrical connection to means for measuring the electrical properties of said element   filling or draining incremental fluid volumes from said tubular structure   measuring the electrical properties of said piezoelectric element at more than one applied alternating current frequency at each increment, and   correlating the electrical properties with the fluid volumes so filled or drained.