MEMS actuator with lower power consumption and lower cost simplified fabrication

Abstract

A microactuator device is disclosed that includes a plurality of generally parallel thin flexible sheets bonded together in a predetermined pattern to form an array of unit cells. Preferably, each of the sheets has only a single electrode layer located on one side of the sheet. Pairs of such sheets are then bonded together at spaced bonding locations with the electrode layers facing one another. Several sets of such sheet pairs can then be bonded together to form a microactuator device.

What is claimed is:  
     
         1 . An actuator array device, comprising: 
 a plurality of generally parallel sheets bonded together in a predetermined pattern to form an array of unit cells; and    selected sheets having a single electrode layer, to form a plurality of electrodes associated with said array of unit cells.    
     
     
         2 . An actuator as recited in  claim 1 , wherein all of said sheets have only a single electrode layer.  
     
     
         3 . An actuator as recited in  claim 1 , wherein said single electrode layer is disposed near the surface of each sheet.  
     
     
         4 . An actuator as recited in  claim 1 , wherein said electrode layer is a thin electrically conductive layer deposited on said sheet and a dielectric layer thereover.  
     
     
         5 . An actuator as recited in  claim 1  wherein the sheets are thin polymer sheets.  
     
     
         6 . An actuator as recited in  claim 1  wherein the sheets are ceramic sheets.  
     
     
         7 . An actuator as recited in  claim 1  wherein the sheets are silicon sheets.  
     
     
         8 . An actuator as recited in  claim 1  wherein the generally parallel sheets lie generally along a plane.  
     
     
         9 . An actuator as recited in  claim 1  wherein the generally parallel sheets lie generally along a curved surface.  
     
     
         10 . An actuator, comprising: 
 a plurality of sheet pairs having a sheet pair length;    said sheet pairs including a first sheet and a second sheet each having a sheet length, wherein said first and second sheets have a front surface and a back surface;    said first and second sheets have a substrate layer disposed toward said back surface, a dielectric layer disposed toward said front surface, and a conductive layer disposed between said substrate layers and said dielectric layers;    said first and second sheet front surfaces being secured together at spaced bonding regions along said sheet length, such that said first and second sheets have non-bonded regions formed between said plurality of spaced bonded regions; and    said sheet pair back surfaces being secured to adjacent sheet pair back surfaces at spaced pair-to-pair bonding regions along the sheet pair lengths.    
     
     
         11 . An actuator as recited in  claim 10 , wherein said non-bonding regions form a plurality of cavities between said first and second sheets with no external force applied to the actuator.  
     
     
         12 . An actuator as recited in  claim 11 , wherein said first sheet is shaped to curve away from said second sheet in said non-bonding regions with no external force applied to the actuator.  
     
     
         13 . An actuator as recited in  claim 12 , wherein said second sheet is substantially flat and lies along a plane defined by said bonding regions.  
     
     
         14 . An actuator as recited in  claim 11 , wherein, in said non-bonding regions, said first and second sheets are shaped to curve away from a plane defined by said bonding regions.  
     
     
         15 . An actuator as recited in  claim 10 , wherein said first and second sheets are both substantially flat and parallel when no external force is applied to the actuator.  
     
     
         16 . An actuator as recited in  claim 15  wherein said first and second sheets become separated in the non-bonding regions when an external force is applied to the actuator.  
     
     
         17 . An actuator as recited in  claim 10  wherein the first and second sheets collectively lie generally along a plane.  
     
     
         18 . An actuator as recited in  claim 10  wherein the first and second sheets collectively lie generally along a curved surface.  
     
     
         19 . An actuator array device, comprising: 
 a plurality of first sheets having sheet lengths;    a plurality of second sheets having sheet lengths;    wherein each of said first and second sheets have a single electrode layer;    pairs of said first and second sheets are operably secured together at spaced bonding regions to form a plurality of sheet pairs; and    adjacent sheet pairs are operably secured together.    
     
     
         20 . An actuator array device as recited in  claim 19 , wherein said second sheets are substantially flat.  
     
     
         21 . An actuator array device as recited in  claim 20 , wherein said first sheets have a plurality of repeating bends, such that said first sheets have peaks and troughs relative to said second sheets.  
     
     
         22 . An actuator array device as recited in  claim 20 , wherein both said first and second sheets are substantially flat.  
     
     
         23 . An actuator array device as recited in  claim 19 , wherein both said first and second sheets have a plurality of repeating bends.  
     
     
         24 . An actuator array device as recited in  claim 19 , wherein the first and second sheets of each sheet pair have repeating cycles of small to large distances therebetween, said large distances being made small by the operation of electrostatic attractive force between said first and second sheets.  
     
     
         25 . An actuator array device as recited in  claim 19 , wherein said single electrode layer forms a surface layer adjacent to said sheet and includes a conductive layer having a dielectric layer thereover.  
     
     
         26 . An actuator array device as recited in  claim 25 , wherein said conductive layer is a metallic layer applied to said sheet.  
     
     
         27 . A method for forming an actuator array device comprising: 
 providing a plurality of sheets;    applying a thin conductive film on only one side of said sheets and depositing a thin dielectric film over said conductive film to locate and pattern one or more electrodes on said sheet surface; and    bonding the plurality of sheets together such that said dielectric layers face each other, in a predetermined pattern to form an array of unit cells.    
     
     
         28 . A method according to  claim 27 , wherein the electrode regions of selected sheets are preformed into corrugations to provide a predetermined mechanical bias between said selected sheets and an adjacent sheet.  
     
     
         29 . A method according to  claim 27 , wherein the electrode regions of all of said sheets are preformed into curved portions to provide a predetermined mechanical bias between said sheets and adjacent sheets.  
     
     
         30 . An actuator, comprising: 
 a plurality of sheet pairs having a sheet pair length;    said sheet pairs including a first sheet and a second sheet each having a sheet length, wherein said first and second sheets have a front surface and a back surface;    said first and second sheets have a substrate layer disposed toward said back surface, a dielectric layer disposed toward said front surface, and a conductive layer disposed between said substrate layers and said dielectric layers;    said first and second sheet front surfaces having one or more trenches defined therein at spaced bonding regions, and an adhesive disposed in selected trenches;    said first and second sheet front surfaces being secured together at the spaced bonding regions by the adhesive in the trenches, such that said first and second sheets have non-bonded regions formed between said plurality of spaced bonded regions; and    said sheet pair back surfaces being secured to adjacent sheet pair back surfaces at spaced pair-to-pair bonding regions along the sheet pair lengths.    
     
     
         31 . A method for forming an actuator array device comprising: 
 providing a first sheet having a front surface and a back surface;    providing a second sheet having a front surface and a back surface;    applying a thin conductive film on said first sheet and second sheet, and applying a dielectric film over said conductive film to locate and pattern one or more electrodes on said first and second sheets; and    defining a first trench in the front surface of the first sheet;    providing an adhesive in the first trench;    positioning the front surface of the first sheet adjacent the front surface of the second sheet so that the first trench is adjacent the second sheet; and    moving the first sheet into engagement with the second sheet.    
     
     
         32 . A method according to  claim 31  further comprising: 
 defining a second trench in the front surface of the second sheet; and  
 positioning the front surface of the first sheet adjacent the front surface of the second sheet so that the first trench is in registration with the second trench.  
 
     
     
         33 . A method according to  claim 32  further comprising: 
 providing an adhesive in the second trench.  
 
     
     
         34 . A method according to  claim 31  wherein the first trench has a length, and the adhesive does not extend the full length of the first trench.  
     
     
         35 . A method according to  claim 31  wherein the first trench extends through the first sheet from the front surface to the back surface.  
     
     
         36 . A method according to  claim 31  further comprising applying at least one catalyst to cure the adhesive.  
     
     
         37 . A method according to  claim 36  wherein the catalyst is heat.  
     
     
         38 . A method according to  claim 36  wherein the catalyst is UV radiation.  
     
     
         39 . A method according to  claim 36  wherein the catalyst is pressure.