Micro-actuator utilizing electrostatic and lorentz forces, and micro-actuator device, optical switch and optical switch array using the same

Abstract

The movable part 21 is fastened to the substrate 11 via flexure parts 27 a and 27 b, and can move upward and downward with respect to the substrate 11. The substrate 11 also serves as a fixed electrode. The movable part 21 has second electrode parts 23 a and 23 b which can generate an electrostatic force between these electrode parts and the substrate 11 by means of a voltage that is applied across these electrode parts and the substrate 11, and a current path 25 which is disposed in a magnetic field, and which generates a Lorentz force when a current is passed through this current path. A mirror 12 which advances into and withdraws from the light path is disposed on the movable part 21. As a result, the mobility range of the movable part can be broadened, and the power consumption can be reduced, without applying a high voltage or sacrificing small size.

1 . A microactuator comprising: 
 one substrate including a first electrode part;    a movable part which is movably disposed with respect to the substrate, and which includes a second electrode part such that an electrostatic force is generated between the second electrode part and the first electrode part when a voltage is applied across the first electrode part and the second electrode part; and    a current path which is disposed in a magnetic field such that a Lorentz force is generated when current is passed through the current path;    wherein the movable part is mechanically connected to the substrate via a spring part.    
   
   
       2 . The microactuator according to  claim 1 , wherein the movable part comprises a thin film.  
   
   
       3 . The microactuator according to  claim 1 , wherein the current path is positioned such that the Lorentz force is generated in a direction that causes the movable part to move into a first position where the electrostatic force is increased.  
   
   
       4 . The microactuator according to  claim 3 , wherein the movable part is movable between the first position and a second position in which the electrostatic force decreases or disappears; and 
 wherein a returning force which urges the movable part to the second position is generated when the movable part is displaced from the second position.    
   
   
       5 . The microactuator according to  claim 4 , wherein the first electrode part and the second electrode part face each other; 
 wherein a gap between the first electrode part and the second electrode part is narrower in the first position than in the second position; and    wherein the returning force is generated by the spring part.    
   
   
       6 . An optical switch comprising: 
 the microactuator according to  claim 1;  and    a mirror which is disposed on the movable part.    
   
   
       7 . An optical switch array comprising a plurality of the optical switches according to  claim 6;   wherein the plurality of optical switches are disposed in a two-dimensional configuration.    
   
   
       8 . The optical switch array according to  claim 7 , further comprising a circuit which includes a plurality of switching elements, and wherein said circuit controls the current and the voltage for respective rows and columns of the optical switches in response to row selection signals and column selection signals for each row and column of the plurality of optical switches.