Resonator with preferred oscillation mode

Abstract

A resonator with mechanical node reinforcement includes a substrate, an intermediate portion adjacent to the substrate, and a resonant portion adjacent to the intermediate portion. The intermediate portion may include multiple layers, such as an insulating layer and/or a conductive layer. The resonant portion of the resonator is adapted for an oscillation mode with a nodal point located within its periphery. Preferably, the resonant portion contacts the intermediate portion at points located at the periphery and at the nodal point. The resonant portion may include multiple layers and its primary layer may be a membrane or a plate. An alternative embodiment of the resonator excludes the intermediate layer allowing the resonant portion to contact the substrate instead of the intermediate layer.

What is claimed is:  
     
         1 . A resonator with mechanical node reinforcement, the resonator comprising, 
 a substrate,    an intermediate portion adjacent to said substrate, and    a resonant portion adjacent to said intermediate portion, said resonant portion being defined by a periphery, and being adapted for a first oscillation mode with a nodal point located within said periphery,    wherein said resonant portion contacts said intermediate portion only at points located substantially at said periphery and substantially at said nodal point.    
     
     
         2 . The resonator of  claim 1  further comprising a contact point located substantially at said nodal point, said contact point interfering with a second oscillation mode.  
     
     
         3 . The resonator of  claim 1  wherein said resonant portion is adapted for a first oscillation mode with a plurality of nodal points located within said periphery, and wherein said resonant portion contacts said intermediate portion only at points located substantially at said periphery and substantially at said plurality of nodal points.  
     
     
         4 . The resonator of  claim 1  wherein said resonant portion is affixed to said intermediate portion only at points located substantially at said periphery and substantially at said nodal point.  
     
     
         5 . The resonator of  claim 1  wherein said intermediate portion comprises a conductive layer, and wherein said resonant portion comprises a structural layer adjacent to said intermediate portion and an electrode layer adjacent to said structural layer.  
     
     
         6 . The resonator of  claim 1  wherein said resonant portion comprises, 
 a structural layer adjacent to said intermediate portion,  
 a conductive layer adjacent to said structural layer,  
 a piezoelectric layer adjacent to said conductive layer, and  
 an electrode layer adjacent to said piezoelectric layer.  
 
     
     
         7 . The resonator of  claim 1  wherein said resonant portion comprises, 
 a structural layer adjacent to said intermediate layer,  
 a conductive layer adjacent to said structural layer,  
 a ferroelectric layer adjacent to said conductive layer, and  
 an electrode layer adjacent to said ferroelectric layer.  
 
     
     
         8 . The resonator of  claim 1  further comprising, 
 a drive transducer coupled to said resonant portion, and adapted to convert a first electrical signal into a wave in said resonant portion, and  
 a sense transducer coupled to said resonant portion, and adapted to convert said wave in said resonant portion into a second electrical signal.  
 
     
     
         9 . The resonator of  claim 8  further comprising, 
 an amplitude control device coupled to said sense transducer, and adapted to calculate a variance by comparing an amplitude represented by said second electrical signal to an amplitude set point, and  
 a phase shift device coupled to said drive transducer, and adapted to transmit a third electrical signal to said drive transducer based on said variance.  
 
     
     
         10 . The resonator of  claim 1  wherein said resonant portion comprises a membrane covered with a film, said film having at least one property that changes upon exposure to an agent, said at least one property affecting said first oscillation mode.  
     
     
         11 . The resonator of  claim 10  wherein said film comprises a chemical or biological receptor.  
     
     
         12 . The resonator of  claim 10  wherein said film comprises an antibody and said agent comprises an antigen.  
     
     
         13 . The resonator of  claim 10  wherein said film comprises a temperature-sensitive film and said agent comprises a change in temperature.  
     
     
         14 . A resonator with mechanical node reinforcement, the resonator comprising, 
 a substrate, and    a resonant layer adjacent to said substrate, said resonant layer being defined by a periphery, and being adapted for an oscillation mode with a nodal point within said periphery,    wherein said resonant layer contacts said substrate only at points located substantially at said periphery and substantially at said nodal point.    
     
     
         15 . The resonator of  claim 14  wherein said resonant layer is adapted for an oscillation mode with a plurality of nodal points within said periphery, and wherein said resonant layer contacts said substrate only at points located substantially at said periphery and substantially at said plurality of nodal points.  
     
     
         16 . The resonator of  claim 14  wherein said resonant layer is affixed to said substrate only at points located substantially at said periphery and substantially at said nodal point.  
     
     
         17 . A method of manufacturing a resonator with mechanical node reinforcement, said method comprising, 
 applying an intermediate portion to a substrate,    applying a sacrificial layer to said intermediate portion, said sacrificial layer being defined by a periphery, and being particularly adapted for an oscillation mode with a nodal point located within said periphery, said sacrificial layer having a void located substantially at said nodal point,    applying a resonant portion to said sacrificial layer and said intermediate portion, said resonant portion extending beyond said periphery and contacting said intermediate portion at said void, and    removing said sacrificial layer such that a gap remains between said intermediate portion and said resonant portion.    
     
     
         18 . The method of  claim 17  further comprising creating said void by etching said sacrificial layer.  
     
     
         19 . The method of  claim 17  further comprising sealing said gap in a vacuum.  
     
     
         20 . The method of  claim 17 , said step of applying said sacrificial layer further comprising applying said sacrificial layer to said intermediate portion, said sacrificial layer being particularly adapted for an oscillation mode with a plurality of nodal points located within said periphery, said sacrificial layer having a plurality of voids located substantially at said plurality of nodal points.  
     
     
         21 . The method of  claim 17  wherein applying said resonant portion to said sacrificial layer and said intermediate portion comprises affixing said resonant portion to said sacrificial layer and said intermediate portion.  
     
     
         22 . The method of  claim 17  further comprising applying an intermediate portion to a substrate by applying a conductive layer to said substrate, and 
 applying a resonant portion to said sacrificial layer and said intermediate portion, by applying a structural layer to said sacrificial layer and said intermediate portion, and applying an electrode layer to said structural layer.  
 
     
     
         23 . The method of  claim 17  wherein said step of applying said resonant portion to said sacrificial layer and said intermediate portion further comprises, 
 applying a structural layer to said sacrificial layer and said intermediate portion,  
 applying a conductive layer to said structural layer,  
 applying a piezoelectric layer to said conductive layer, and  
 applying an electrode layer to said piezoelectric layer.  
 
     
     
         24 . The method of  claim 17  wherein said step of applying said resonant portion to said sacrificial layer and said intermediate portion further comprises, 
 applying a structural layer to said sacrificial layer and said intermediate portion,  
 applying a conductive layer to said structural layer,  
 applying a ferroelectric layer to said conductive layer, and  
 applying an electrode layer to said ferroelectric layer.  
 
     
     
         25 . The method of  claim 17  further comprising, 
 applying a drive transducer to said resonant portion, said drive transducer converting a first electrical signal into a wave in said resonant portion, and  
 applying a sense transducer to said resonant portion, said sense transducer converting said wave in said resonant portion into a second electrical signal.  
 
     
     
         26 . The method of  claim 25  further comprising, 
 putting an amplitude control device in electrical signal communication with said sense transducer, said amplitude control device calculating a variance by comparing an amplitude represented by said second electrical signal to an amplitude set point, and  
 putting a phase shift device in electrical signal communication with said drive transducer, said phase shift device transmitting a third electrical signal to said drive transducer based on said variance.  
 
     
     
         27 . The method of  claim 17  wherein said step of applying said resonant portion further comprises applying a film to said resonant portion, said film having at least one property that changes upon exposure to an agent, said at least one property affecting said oscillation mode of said resonant layer.  
     
     
         28 . The method of  claim 27  wherein said step of applying said film further comprises applying said film to said resonant portion, said film comprising a chemical or biological receptor.  
     
     
         29 . The method of  claim 27  wherein said step of applying said film further comprises applying said film to said resonant portion, said film comprising an antibody and said agent comprises an antigen.  
     
     
         30 . The method of  claim 27  wherein said step of applying said film further comprises applying said film to said resonant portion, said film comprising a temperature-sensitive film and said agent comprises a change in temperature.  
     
     
         31 . A method of manufacturing a resonator with mechanical node reinforcement, said method comprising, 
 applying a sacrificial layer to a substrate, said sacrificial layer being defined by a periphery, and being particularly adapted for an oscillation mode with a nodal point located within said periphery, said sacrificial layer having a void located substantially at said nodal point,    applying a resonant layer to said sacrificial layer and said substrate, said resonant layer extending beyond said periphery and contacting said substrate at said void, and    removing said sacrificial layer such that a gap remains between said substrate and said resonant layer.    
     
     
         32 . The method of  claim 31 , said step of applying said sacrificial layer further comprising applying said sacrificial layer to said substrate, said sacrificial layer being adapted for an oscillation mode with a plurality of nodal points located within said periphery, said sacrificial layer having a plurality of voids located substantially at said plurality of nodal points.  
     
     
         33 . The method of  claim 31  wherein applying a resonant layer to said sacrificial layer and said substrate comprises affixing said resonant layer to said sacrificial layer and said substrate.