Piezoelectric Cooling Fan

Abstract

A piezoelectric cooling fan comprises a support frame and two piezoelectric actuators. Each piezoelectric actuator includes an electrical-conductive plate and a piezoelectric plate attached to the electrical-conductive plate, wherein an edge portion of the electrical-conductive plate is fixedly attached to a base of the support frame and approximately aligned with an edge portion of the piezoelectric plate attached thereto. The two piezoelectric actuators are symmetrically arranged with respect to the base of the support frame to define a cavity therebetween and are electrically connected with an AC power source, so that the piezoelectric actuators can be driven to flex towards and away from each other with respect to the edge portions of the piezoelectric actuators, so that air pulses can be induced from the cavity between the piezoelectric actuators for heat dissipation. The piezoelectric cooling fan is light, compact, low noise, low power, and free of electromagnetic interference.

I claim: 
     
         1 . A piezoelectric cooling fan, comprising:
 a support frame, and   two piezoelectric actuators each including an electrical-conductive plate and a piezoelectric plate attached to the electrical-conductive plate, wherein an edge portion of the electrical-conductive plate is fixedly attached to a base of the support frame and approximately aligned with an edge portion of the piezoelectric plate attached thereto, the two piezoelectric actuators being symmetrically arranged with respect to the base of the support frame to define a cavity therebetween and being electrically connected with an AC power source, so that the piezoelectric actuators can be driven to flex towards and away from each other with respect to the edge portions of the electrical-conductive plates and the piezoelectric plates, so that air pulses can be induced from the cavity between the piezoelectric actuators for heat dissipation.   
     
     
         2 . The piezoelectric cooling fan of  claim 1 , further comprising two protective covers being respectively placed over the piezoelectric plates and mounted to the support frame 
     
     
         3 . The piezoelectric cooling fan of  claim 2 , wherein the protective covers are made of resin, paper, or composite material. 
     
     
         4 . The piezoelectric cooling fan of  claim 1 , wherein each electrical-conductive plate is rectangular and has a length of Lm, an effective length of Lme, and an effective width of Wme; each piezoelectric plate is rectangular and has a length of Lc, an effective length of Lce, and an effective width of Wee; wherein the ratio of Lce to Lme is less than or equal to 1.0 and is greater than or equal to 0.1; the ratio of Wce to Wme is less than or equal to 1.0 and is greater than or equal to 0.5., and wherein all the ratios are further limited such that the ratio of Lee to Lme is less than or equal to 0.6 and is greater than or equal to 0.4; the ratio of Wce to Wme is less than or equal to 1.0 and is greater than or equal to 0.96. 
     
     
         5 . The piezoelectric cooling fan of  claim 1 , wherein the support frame is made of metal, plastic, engineering plastic, ceramic, or composite material. 
     
     
         6 . The piezoelectric cooling fan of  claim 1 , wherein the electrical-conductive plates are made of metal or composite material with electrical conductivity