Vertical comb drive actuated deformable mirror device and method

Abstract

A deformable mirror includes a vertical comb actuator having a reflective surface attached thereto. The vertical comb drive includes stationary elements interspersed with moving elements. When a potential difference is provided between these elements, the moving elements are pulled downward, thereby deforming the reflective surface. The vertical comb drive typically includes a plurality of actuators, which are individually electrically addressed. Each actuator may be an array of interspersed elements or a cavity and corresponding tooth. Springs support the moving elements and bias the reflective surface in an original position. The vertical comb drive provides a large stroke and substantially linear voltage-versus-displacement curve throughout the stroke.

What is claimed is:  
     
         1 . A deformable mirror comprising: 
 a vertical comb drive; and    a reflective surface attached to said vertical comb drive.    
     
     
         2 . The deformable mirror according to  claim 1 , further comprising a spring for biasing said vertical comb drive to maintain said reflective surface in an original position absent application of a voltage to said vertical comb drive.  
     
     
         3 . The deformable mirror according to  claim 1 , wherein said vertical comb drive comprises a first array of stationary elements and a second array of moving elements correspondingly interspersed with said first array, said reflective surface being attached to said second array.  
     
     
         4 . The deformable mirror according to  claim 3 , further comprising a layer covering tops of elements of said second array.  
     
     
         5 . The deformable mirror according to  claim 4 , a spring for suspending said first array relative to said second array, said spring being attached to said layer.  
     
     
         6 . The deformable mirror according to  claim 3 , wherein said stationary elements and said movable elements are circular.  
     
     
         7 . The deformable mirror according to  claim 3 , wherein said stationary elements and said movable elements are planar.  
     
     
         8 . The deformable mirror according to  claim 4 , wherein said layer is attached directly to said reflective surface.  
     
     
         9 . The deformable mirror according to  claim 4 , further comprising a post attaching said layer to said reflective surface.  
     
     
         10 . The deformable mirror according to  claim 9 , wherein said post is in a center of said reflective surface.  
     
     
         11 . The deformable mirror according to  claim 3 , wherein voltage is applied to each stationary element of said first array individually or each moving element of said second array individually.  
     
     
         12 . The deformable mirror according to  claim 3 , wherein said vertical comb drive comprises an array of vertical comb actuators.  
     
     
         13 . The deformable mirror according to  claim 12 , means for individually providing voltage to each actuator of said array.  
     
     
         14 . The deformable mirror according to  claim 12 , further comprising springs for individually suspending each of said second array of each actuator in said array.  
     
     
         15 . The deformable mirror according to  claim 14 , further comprising an anchor for supporting said springs.  
     
     
         16 . The deformable mirror according to  claim 1 , wherein said vertical comb drive comprises plurality of cavities and teeth interdigitally mounted with said cavities, said reflective surface being attached to said teeth.  
     
     
         17 . The deformable mirror according to  claim 16 , further comprising a top layer between the teeth and the reflective surface.  
     
     
         18 . The deformable mirror according to  claim 16 , further comprising a conductor for individually connecting each tooth of said teeth to a voltage source.  
     
     
         19 . A method of deforming a mirror comprising: 
 attaching the mirror to a vertical comb actuator; and    applying a voltage to the vertical comb actuator.    
     
     
         20 . The method according to  claim 19 , wherein said vertical comb drive comprises an array of vertical comb actuators and said applying individually applies voltage to said vertical comb actuators.  
     
     
         21 . A deformable mirror comprising: 
 a vertical electrostatic comb drive including a first array of stationary elements and a second array of moving elements correspondingly interspersed with said first array;    a reflective surface attached to said second array;    a layer covering tops of elements of said second array; and    a resilient member for suspending said first array relative to said second array, said resilient member being attached to said layer.    
     
     
         22 . The deformable mirror according to  claim 21 , wherein said stationary elements and said movable elements are circular.  
     
     
         23 . The deformable mirror according to  claim 21 , wherein said stationary elements and said movable elements are planar.  
     
     
         24 . The deformable mirror according to  claim 21 , wherein said layer is attached directly to said reflective surface.  
     
     
         25 . The deformable mirror according to  claim 21 , wherein voltage is applied to each stationary element of said first array individually or each moving element of said second array individually.  
     
     
         26 . The deformable mirror according to  claim 21 , wherein said vertical comb drive comprises an array of vertical comb actuators.  
     
     
         27 . The deformable mirror according to  claim 21 , wherein said vertical comb drive comprises plurality of cavities and teeth interdigitally mounted with said cavities, said reflective surface being attached to said teeth.  
     
     
         28 . The deformable mirror according to  claim 21 , wherein said resilient member is a torsionsal spring.  
     
     
         29 . A displaceable surface comprising: 
 a vertical electrostatic comb drive;    a surface attached to said vertical comb drive, wherein said vertical comb drive comprises a first array of stationary elements and a second array of moving elements correspondingly interspersed with said first array, said surface defining a plane and being attached to said second array, said surface being displaced in a direction orthogonal to the plane thereof when said vertical electrostatic comb drive is actuated;    a layer covering tops of elements of said second array; and    a bar for suspending said second array relative to said first array.    
     
     
         30 . The displaceable surface of  claim 29 , wherein a mirror is provided in said surface.  
     
     
         31 . The displaceable surface of  claim 29 , wherein said bar produces a torsional force to return the deformable surface to a position corresponding to the position before the surface is displaced.  
     
     
         32 . The displaceable surface of  claim 29 , wherein said bar is attached between said surface and a wall.  
     
     
         33 . The displaceable surface of  claim 29 , wherein the vertical electrostatic comb drive is provided on a substrate and said surface is generally parallel to said substrate.  
     
     
         34 . The displaceable surface of  claim 29 , wherein said surface is reflective.