Apparatus and method for optical manufacturing

Abstract

An apparatus and method for lens surfacing. The apparatus includes a voice coil, piezo stack and cutter connected by a connection mechanism and regulated by a hierarchical sliding mode control system. The invention allows for both coarse and fine movements of the cutter during surfacing.

1 . A dual-stage actuation system for high precision optical manufacturing, comprising: a connection mechanism for a dual-stage actuator cutting tool that minimizes displacement loss, and maximizes robustness of the actuator cutting system. 
     
     
         2 . The system in  claim 1  having the dual-stage actuator cutting tool further including a voice coil actuator, piezo stack and a cutter, and the connection mechanism further provides a seamless connection between the voice coil actuator, piezo stack and the cutter to avoid vibration. 
     
     
         3 . A control system for a dual-stage actuation cutter system, comprising:
 a hierarchical sliding mode control that is defined as the intersection of two hyper-planes, wherein the first hyper-plane is constructed using the partial stats of the system that correspond to the coarse motion, and the second is constructed using the partial states of the system that correspond to the fine motion.   
     
     
         4 . The system in  claim 3 , wherein the sliding mode control provides high frequency disturbance and vibration compensation to compensate for cutting and grinding forces of micro-surfacing, and maintains sub-nanometer micro-surfacing resolution, and allows smooth transitioning between the coarse and fine motion stages. 
     
     
         5 . A dual-stage servo actuator system for optical manufacturing, comprising a unitary tool that allows for both course and fine positioning, and
 a mechanism for smooth and effective operation of the dual-stage actuation tool.   
     
     
         6 . The system in  claim 5 , further including a tracking control system using a hierarchal sliding mode approach specifically tailored to maintain sub-nanometer level resolution during micro-surfacing. 
     
     
         7 . The system of  claim 6 , wherein the tracking control system allows the dual-stage actuator cutter to deal with uncertain disturbances and vibrations the actuator will encounter while micro-surfacing. 
     
     
         8 . The system in  claim 5 , further including an actuator portion having a voice coil, piezo stack actuator, and cutter in series, the connection mechanism seamlessly connecting the piezo stack actuator to the cutter and to the voice coil. 
     
     
         9 . The system in  claim 7 , wherein the voice coil covers long-range motion of the actuator during a coarse positioning stage, and the piezo stack actuator covers short-range motion of the cutter during a fine positioning stage. 
     
     
         10 . The system in  claim 9 , wherein the coarse position stage includes multiple inch displacement with a motion frequency of less than 250 Hz and a positioning resolution of greater than 100 nm. 
     
     
         11 . The system in  claim 9 , wherein the fine position stage includes up to 200 μm displacement with a motion frequency of less than 3 kHz and a positioning resolution of less than 1 nm. 
     
     
         12 . The system of  claim 5 , wherein the connection mechanism is designed to avoid vibration below 3 kHz while minimizing stroke loss from the piezo stroke to the cutting tool. 
     
     
         13 . A method of high precision optical manufacturing, comprising:
 utilizing a dual stage actuation system to minimize or eliminate lens fining and polishing from conventional lens processing.   
     
     
         14 . The method of  claim 13 , further including bringing a surface roughness less than 50 nm. 
     
     
         15 . A method of high precision optical manufacturing comprising:
 blocking a lens;   machining the lens utilizing a dual-stage actuation system;   cleaning and coating the lens.   
     
     
         16 . The method of  claim 15  wherein lens fining and polishing is eliminated 
     
     
         17 . The method of  claim 16  wherein lens fining and polishing is reduced as compared to traditional lens manufacturing technology. 
     
     
         18 . The method of  claim 15 , wherein the dual-stage actuation system includes a connection mechanism. 
     
     
         19 . The method of  claim 15 , further includes allowing a cutter tracking motion over 200 Hz. 
     
     
         20 . The method of  claim 15 , further includes allowing positioning resolution less than 0.1 μm.