Low optical power hysteresis liquid lenses

1. An electrowetting optical device comprising:

a conductive liquid and a non-conductive liquid, said liquids being non miscible; and

a dielectric enclosure on which both fluids are in contact and form a triple interface,

wherein the non-conductive liquid comprises from 0.0001 weight percent to about 1 weight percent of a surface adsorbing agent, the surface adsorbing agent being an amphiphilic molecule having a solubility in water lower than about 0.1 weight percent at 25° C.

2. The electrowetting optical device according to claim 1 , wherein the surface adsorbing agent is configured to form a protective layer on the dielectric enclosure; and/or decrease the optical power hysteresis of the electrowetting optical device; and/or prevent a drift of the optical power causing hysteresis during aging of the electrowetting optical device; and/or decrease by at least 5° the contact angle of the non-conductive liquid on the surface of the dielectric enclosure in the presence of the conductive liquid.

3. The electrowetting optical device according to claim 1 ,

wherein the surface adsorbing agent is identified via a first reference experiment consisting of:

measuring a contact angle of a mixture of 0.0001 to 1 weight % of the surface adsorbing agent in phenyltrimethylsilane on parylene C in the presence of ethylene glycol, the measured contact angle being 18° or less; and/or

wherein the surface adsorbing agent is identified via a second reference experiment consisting of:

depositing a drop of the non-conductive liquid containing 0.0001 to 1 weight % of the surface adsorbing agent on the dielectric enclosure in the presence of the conductive fluid;

recording a contact angle hysteresis before a continuous application of a voltage between the conductive liquid and an electrode placed under the dielectric enclosure;

continuously applying an AC 1 kHz square voltage for at least 24 h between the conductive liquid and the electrode, said voltage being chosen to induce a variation of at least 20° of the contact angle without saturation; and

recording a contact angle hysteresis after the continuous application of the voltage, a difference between the contact angle hysteresis before and after application of the voltage being lower than 5°.

4. The electrowetting optical device according to claim 1 , wherein the surface adsorbing agent is selected from the group consisting of:

a dialkylsiloxane polymer or copolymer; a polyethoxylated alkylphenol; a polyol fatty acid ester; a C8 to C18 fatty alcohol; a polyethoxylated fatty alcohol; a dialkyl sodium sulfosuccinate; a glycerophospholipid; and a mixture thereof.

5. The electrowetting optical device according to claim 4 , wherein the dialkylsiloxane polymer or copolymer comprises more than 20 dialkylsiloxane units, and/or has a molecular weight ranging from about 3000 g/mol to about 15000 g/mol.

6. The electrowetting optical device according to claim 4 , wherein the alkyl groups of the dialkylsiloxane are identical or different and comprise less than 12 carbon atoms, and/or are each saturated or unsaturated and are each a linear, cyclic or branched hydrocarbon group.

7. The electrowetting optical device according to claim 4 , wherein the surface adsorbing agent is selected from the group consisting of a polydimethylsiloxane-polyethyleneoxide copolymer, a polyalkylmethylsiloxane-hydroxypolyalkyleneoxypropylmethylsiloxane copolymer, a polydimethylsiloxane-hydroxypolyethyleneoxypropylmethylsiloxane copolymer, a polydimethylsiloxane-methoxypolyethyleneoxypropylmethylsiloxane copolymer, a polydimethylsiloxane-alcoxypolyethyleneoxypropylmethylsiloxane copolymer, a polydimethysiloxane-poly aminopropylmethylsiloxane copolymer, a hydroxyl terminated polydimethylsiloxane polymer, a hydroxyl terminated polydimethylsiloxane-polyalkylmethylsiloxane copolymer, a hydroxyl terminated polydimethylsiloxane-polydiphenylsiloxane copolymer, and a mixture thereof.

8. The electrowetting optical device according to claim 4 , wherein the surface adsorbing agent is a polyethoxylated nonylphenol or lecithin.

9. The electrowetting optical device according to claim 4 , wherein the polyethoxylated fatty alcohol is a C16-C18 polyethoxylated fatty alcohol.

10. The electrowetting optical device according to claim 4 , wherein the polyol fatty acid ester is a sorbitan fatty acid ester and/or a polyol of a C16-C22 fatty acid.

11. The electrowetting optical device according to claim 4 , wherein the C8-C18 fatty alcohol is dodecanol, or is fluorinated or perfluorinated.

12. A liquid lens comprising the electrowetting optical device according to claim 1 .

13. An apparatus comprising the liquid lens according to claim 12 .