Electroactive Optical Device

Abstract

An electroactive optical device, in particular an electroactive lens, comprising an optical element ( 1 ) as well as an electroactive element ( 2 ) is described. The optical element ( 1 ) is an elastic solid, such as a gel or a polymer. The electroactive element ( 2 ) comprises a plurality of compliant electrodes ( 3 a - 3 e ) stacked on top of each other with an electroactive material ( 5 ) between them. The electroactive element ( 2 ) is surrounded by a rigid wall ( 4 a, 4 b ), which provides two common contacts for the electrodes ( 3 a - 3 e ). In the absence of an applied electric voltage, the optical element ( 1 ) is in a mechanically relaxed state, which reduces undesired ageing effects. Upon application of a voltage to the electrodes ( 3 a - 3 e ) the optical element ( 2 ) is deformed.

1 . An electroactive optical device, in particular an electroactive lens, comprising
 an elastic optical element ( 1 ),   an electroactive element ( 2 ) arranged laterally adjacent to said optical element ( 1 ) and comprising at least one electrode pair of two electrodes ( 3   a - 3   e ) with an elastic electroactive material ( 5 ) arranged between said electrode pair,   wherein upon application of a voltage over said at least one electrode pair an axial distance between said electrodes changes, thereby varying a volume of a first region in said optical element adjacent to said electrode pair, thereby radially displacing material in said optical element ( 1 ) between said first region and a second region of said optical element ( 1 ), wherein one of said regions elastically expands and the other elastically contracts in an axial direction, thereby bringing said optical element ( 1 ) into a deformed state, while, in the absence of a voltage over said at least one electrode pair, said optical element ( 1 ) is in an elastically relaxed state.   
     
     
         2 . The electroactive optical device of  claim 1  wherein said electroactive element ( 2 ) comprises a plurality of electrode pairs stacked on top of each other with a plurality of gaps between said electrode pairs, and in particular wherein said gaps are filled by said electroactive material. 
     
     
         3 . The electroactive optical device of any of the preceding claims wherein the optical element ( 1 ) is a solid or a gel. 
     
     
         4 . The electroactive optical device of any of the preceding claims wherein the electroactive element ( 2 ) comprises or consists of a material selected from the group comprising gels, polymers, acrylic materials and elastomers. 
     
     
         5 . The electroactive optical device of any of the preceding claims wherein the optical element ( 1 ) is the same material as the electroactive material ( 5 ). 
     
     
         6 . The electroactive optical device of any of the  claims 1  to  4  wherein the optical element ( 1 ) is of a material different from the electroactive material ( 5 ). 
     
     
         7 . The electroactive optical device of any of the preceding claims wherein said electro active element ( 2 ) surrounds said optical element ( 1 ). 
     
     
         8 . The electroactive optical device of any of the preceding claims wherein said optical material is arranged at a first side of said electroactive element ( 2 ) and wherein said electroactive optical device further comprises a solid wall ( 4   a ,  4   b ) at a second side of said electroactive element ( 2 ), wherein said second side is opposite to said first side. 
     
     
         9 . The electroactive optical device of  claim 8  wherein each of said electrodes ( 3   a - 3   e ) is electrically connected to one of at least two different sections ( 4   a ,  4   b ) of said wall. 
     
     
         10 . The electroactive optical device of any of the preceding claims wherein said electroactive element ( 2 ) comprises at least one electrode made from at least one material selected from the group comprising carbon nanotubes, carbon black, carbon grease, metal ions, fluid metals, metallic powders, conductive polymers, and rigid electrodes connected to deformable leads. 
     
     
         11 . The electroactive optical device of any of the preceding claims further comprising a solid substrate ( 7 ), and in particular wherein said electroactive element ( 2 ) and said optical element ( 1 ) are arranged on said substrate ( 7 ). 
     
     
         12 . The electroactive optical device of  claim 11  further comprising a buffer layer ( 30 ) arranged between said substrate ( 7 ) and said electroactive element ( 2 ) and said optical element ( 1 ), wherein said buffer layer ( 30 ) has a Young's modulus smaller than or equal to the Young's modulus of said optical element ( 1 ), and in particular wherein said buffer layer ( 30 ) is attached to said substrate ( 7 ). 
     
     
         13 . The electroactive optical device of any of the preceding claims further comprising a lid layer ( 30 ) attached to said optical element ( 1 ), wherein said lid layer ( 30 ) has a Young's modulus larger than a Young's modulus of said optical element ( 1 ). 
     
     
         14 . The electroactive optical device of any of the preceding claims wherein a distance between neighboring electrodes ( 3   a - 3   e ) is less than 250 μm, in particular approximately 10 μm. 
     
     
         15 . The electroactive optical device of any of the preceding claims wherein an inner diameter of at least one of the electrodes ( 3   a - 3   e ) is different from the inner diameter of at least some of the other electrodes,
 and in particular wherein an electrode ( 3   a ) closest to a top surface of said optical device has a larger inner diameter than a next lower electrode ( 3   b ), wherein the top surface is the surface that is deformed upon application of a voltage.   
     
     
         16 . The electroactive optical device of any of the preceding claims further comprising a mirror element ( 25 ) on at least one surface of said optical element ( 1 ). 
     
     
         17 . The electroactive optical device of any of the preceding claims further comprising a rigid element ( 26 ) in the optical element. 
     
     
         18 . The electroactive optical device of any of the preceding claims further comprising an antireflective layer on at least one surface of said optical element, and in particular wherein said antireflective layer comprises structures having a size smaller than 400 nm. 
     
     
         19 . The electroactive optical device of any of the preceding claims wherein said optical element ( 1 ) is of an inhomogeneous hardness, in particular wherein said optical element comprises an inhomogeneously polymerized polymer. 
     
     
         20 . The electroactive optical device of any of the preceding claims wherein, upon application of a voltage over said at least one electrode pair, said electroactive material ( 5 ) is compressed and exerts a lateral pressure onto said optical element ( 1 ), thereby bringing said optical element ( 1 ) into said deformed state. 
     
     
         21 . The electroactive optical device of any of the preceding claims wherein said electroactive material is such that upon application of the voltage over said at least one electrode pair the axial distance between said electrodes decreases, thereby compressing said first region, thereby radially displacing material in said optical element ( 1 ) away from said first region into said second region. 
     
     
         22 . An assembly of at least two electroactive devices ( 11   a ,  11   b  . . . ) of any of the preceding claims on top of each other. 
     
     
         23 . The assembly of  claim 22  wherein said electroactive devices ( 11   a ,  11   b  . . . ) are mounted to opposite sides of a common solid substrate ( 7 ). 
     
     
         24 . A method for manufacturing the electroactive optical device of any of the preceding claims comprising the steps of
 a) providing a plurality of first electrodes ( 3   e ),   b) applying, over said first electrodes ( 3   e ), a layer ( 5   a ) of electroactive material,   c) applying a plurality of second electrodes ( 3   d ) over said layer ( 5   a ) of electroactive material, with each second electrode ( 3   d ) attributed to a first electrode ( 3   e ), and   d) separating a resulting product of said steps a), b) and c) into a plurality of said electroactive devices.   
     
     
         25 . The method of  claim 24  wherein said steps b) and c) are repeated for forming a plurality of electrode pairs on top of each other. 
     
     
         26 . The method of any of the  claim 24  or  25  wherein said plurality of first electrodes ( 3   e ) is arranged on a solid substrate ( 7 ). 
     
     
         27 . The method of any of the  claims 24  to  26  wherein said step b) comprises the application of said electroactive material ( 5 ) by a method selected from the group comprising spin coating, spraying, printing, applying a prefabricated material layer, and chemical vapor deposition, in particular plasma-enhanced chemical vapor deposition. 
     
     
         28 . The method of any of the  claims 24  to  27  wherein solid walls ( 4   a ,  4   b ) are inserted into said layers ( 5   a ,  5   b , . . . ) of electroactive material ( 5 ) for contacting the electrodes ( 3   a - 3   e ). 
     
     
         29 . The method of any of the  claims 24  to  28  wherein said optical element ( 1 ) made from a single piece of material.