Contact structure for a tunable liquid crystal optical device

Abstract

A tunable liquid crystal optical device defining an optical aperture and having a layered structure. The device includes a film electrode formed on a surface of a first substrate and covered by a second substrate, and a contact structure filling a volume within the layered structure and contacting the film electrode. The contact structure is located outside of the optical aperture and provides an electrical connection surface much larger than a thickness of the film electrode, such that reliable electrical connections may be made to the electrode, particularly in the context of wafer scale manufacturing of such a device.

1 - 22 . (canceled) 
     
     
         23 . A tunable liquid crystal optical device defining an optical aperture and having a layered structure, said device comprising:
 a first substrate having an upper surface and a side edge;   a first film electrode on the upper surface, the first film electrode having a bottom surface on the upper surface and also having a top surface, a side edge between the first film electrode bottom surface and the first film electrode top surface, and a first thickness between the first film electrode top surface and the first film electrode bottom surface; and   a second substrate having an upper surface, a lower surface on the top surface of the first film electrode, a side edge, a second thickness between the second substrate upper surface and the second substrate lower surface at a central portion of the second substrate and a third thickness between the second substrate upper surface and the second substrate lower surface at the second substrate side edge,   the lower surface of the second substrate being spaced from the top surface of the first film electrode at the side edge of the second electrode such that a cavity is formed between the lower surface of the second substrate and the top surface of the first film electrode inward of the side edge of the first film electrode,   wherein a distance from the top edge of the first film electrode at the side edge of the first film electrode to the lower surface of the second substrate at the side edge of the second substrate is greater than the first thickness.   
     
     
         24 . The device as defined in  claim 23 , wherein the cavity is filled with ambient air. 
     
     
         25 . The device as defined in  claim 23 , wherein the cavity is filled with a body of conductive material in electrical contact with the top surface of the first film electrode. 
     
     
         26 . The device as defined in  claim 25 , wherein the body of conductive material includes an exposed side edge connecting the side edge of the second substrate and the side edge of the first film electrode. 
     
     
         27 . The device as defined in  claim 23 , wherein the cavity is filled with a body of temporary filler material in contact with the top surface of the first film electrode. 
     
     
         28 . The device as defined in  claim 23 , wherein the lower surface of the second substrate defines a wall of the cavity and wherein the wall of the cavity curves toward the top surface of the first film electrode. 
     
     
         29 . The device as defined in  claim 23 , further including a second film electrode formed on a substrate other than the first substrate and a body of conductive material including a first contact area contacting said first film electrode and a second contact area contacting said second film electrode. 
     
     
         30 . The device as defined in  claim 23 , further including a second film electrode formed on a substrate other than said first substrate, said second film electrode having an exposed edge. 
     
     
         31 . The device as defined in  claim 23 , wherein said first film electrode comprises a thin film transparent electrode configured to control an electric field for said device. 
     
     
         32 . The device as defined  claim 23 , wherein said device comprises a pair of identical single polarization layered liquid crystal optical devices joined together after a 90 degree rotation and flip of one of said pair of devices and a contact structure including two pairs of vertically aligned contact areas. 
     
     
         33 . The device as defined in  claim 23 , wherein said device is made a number at a time by a wafer process and then singulated. 
     
     
         34 . A method of manufacturing a tunable liquid crystal optical device that defines an optical aperture and has a layered structure including a liquid crystal layer and a lens structure layer, said method comprising:
 forming a first wafer including a planar array of first substrates;   forming a film electrode on a surface of each of said first substrates;   forming a second wafer including a planar array of second substrates, said second wafer including a plurality of grooves between the second substrates;   forming a stacked structure by attaching the second wafer to the first film electrode such that the plurality of grooves face the first film electrode;   sectioning said stacked structure into multiple optical devices along the plurality of grooves.   
     
     
         35 . The method as defined in  claim 34 , wherein each of the plurality of grooves has a depth substantially greater than a thickness of the film electrode. 
     
     
         36 . The method as defined in  claim 35 , including placing a body of conductive material in each of the plurality of grooves. 
     
     
         37 . The method as defined in  claim 35 , including placing a body of temporary filler material in each of the plurality of grooves. 
     
     
         38 . A method as defined in  claim 34 , wherein before sectioning said stacked structure, joining a pair of identical layered liquid crystal optical devices together after a 90 degree rotation and flip of one of said pair of devices. 
     
     
         39 . A tunable liquid crystal optical device having a layered structure having a thickness and singulated from a number of tunable liquid crystal optical devices made at a time by a wafer process, the tunable optical device defining an optical aperture, said device comprising:
 a plurality of substrates, each substrate having a common lateral extent defined by common singulation of said substrates;   at least one liquid crystal layer sandwiched by a pair of said plurality of substrates;   a film electrode formed on a surface of a first substrate of the plurality of substrates;   a body of conductive material filling a volume within said layered structure outside said optical aperture, said body of conductive material being formed over cut lines defining said lateral extent of said singulated substrates and having:   a first contact area in electrical contact with said film electrode; and   a second contact area exposed on a peripheral surface of said singulated layered structure providing an external electrical connection, said body of conductive material at said second contact area having a thickness substantially greater than a thickness of said film electrode.