Non-aqueous conductive liquids for liquid lenses
An electrowetting optical device having a non-aqueous conductive liquid and a non-conductive liquid, the liquids being non-miscible, and a dielectric enclosure on which both liquids are in contact and form a triple interface. The non-aqueous conductive liquid includes a non-ionic polar organic solvent, and at least 2 weight % of a first compound, where the first compound is non-aqueous and is either ionic or non-ionic. If the first compound is non-ionic, the first compound is more polar than the solvent, the polarity of the non-ionic first compound being measured by Hansen parameters, a sum of the Hansen parameter for polarity (δ p ) and of the Hansen parameter for hydrogen bonding (δ h ) being higher than the sum of the corresponding Hansen parameters of the non-ionic polar organic solvent, and the non-aqueous conductive liquid having an ionic second compound.
1. An electrowetting optical device comprising:
a non-aqueous conductive liquid and a non-conductive liquid, said liquids being non-miscible; and
a dielectric enclosure on which both liquids are in contact and form a triple interface,
wherein
the non-aqueous conductive liquid comprises:
a non-ionic polar organic solvent, and
at least 2 weight % of a first compound;
wherein
the first compound is non-aqueous and is ionic or non-ionic;
wherein, if the first compound is non-ionic,
the first compound is more polar than the solvent, the polarity of the non-ionic first compound being measured by Hansen parameters, a sum of the Hansen parameter for polarity (δ p ) and of the Hansen parameter for hydrogen bonding (δ h ) being higher than the sum of the corresponding Hansen parameters of the non-ionic polar organic solvent, and
the non-aqueous conductive liquid further comprises an ionic second compound, and
wherein, if the first compound is ionic,
the non-aqueous conductive liquid further comprises from 0.01 weight % to 6 weight % of water.
2. The electrowetting optical device according to claim 1 , wherein the non-aqueous conductive liquid comprises less than 5 weight % of water.
3. The electrowetting optical device according to claim 1 , wherein the non-aqueous conductive liquid comprises less than 5 weight % of the ionic second compound.
4. The electrowetting optical device according to claim 1 , wherein the non-aqueous conductive liquid has a freezing point lower than −20° C. at 1 bar.
5. The electrowetting optical device according to claim 1 , wherein the solvent comprises at least two hydroxyl functions.
6. The electrowetting optical device according to claim 1 , wherein the solvent has a boiling point over 120° C. at 1 bar.
7. The electrowetting optical device according to claim 1 , wherein the solvent is selected from the group comprising ethane-1,2-diol, propane-1,3-diol, propane-1,2-diol, and propane-1,2,3-triol, and any combination thereof.
8. The electrowetting optical device according to claim 1 , wherein the first compound has a boiling point over 120° C. at 1 bar.
9. The electrowetting optical device according to claim 1 , wherein any further compound comprised in the non-aqueous conductive liquid has a boiling point over 120° C. at 1 bar.
10. A liquid lens comprising the electrowetting optical device according to claim 1 .
11. An apparatus comprising the liquid lens according to claim 10 .
12. A method for providing an electrowetting optical device, the method comprising:
providing a dielectric enclosure; and
forming a triple interface by contacting a non-aqueous conductive liquid and a non-conductive liquid on the dielectric enclosure, said liquids being non-miscible,
wherein
the non-aqueous conductive liquid comprises:
a non-ionic polar organic solvent, and
at least 2 weight % of a first compound;
wherein
the first compound is non-aqueous and is ionic or non-ionic;
wherein, if the first compound is non-ionic,
the first compound is more polar than the solvent, the polarity of the non-ionic first compound being measured by Hansen parameters, a sum of the Hansen parameter for polarity (δ p ) and of the Hansen parameter for hydrogen bonding (δ h ) being higher than the sum of the corresponding Hansen parameters of the non-ionic polar organic solvent, and
the non-aqueous conductive liquid further comprises an ionic second compound, and
wherein, if the first compound is ionic,
the non-aqueous conductive liquid further comprises from 0.01 weight % to 6 weight % of water.
13. Use of a non-aqueous conductive liquid as a component of an electrowetting optical device, the non-aqueous conductive liquid comprising:
a non-ionic polar organic solvent, and
at least 2 weight % of a first compound,
wherein
the first compound is non-aqueous and is ionic or non-ionic;
wherein, if the first compound is non-ionic,
the first compound is more polar than the solvent, the polarity of the non-ionic first compound being measured by Hansen parameters, a sum of the Hansen parameter for polarity (δ p ) and of the Hansen parameter for hydrogen bonding (δ h ) being higher than the sum of the corresponding Hansen parameters of the non-ionic polar organic solvent, and
the non-aqueous conductive liquid further comprises an ionic second compound, and
if the first compound is ionic,
the non-aqueous conductive liquid further comprises from 0.01 weight % to 6 weight % of water.
14. The electrowetting optical device according to claim 1 , wherein if the first compound is ionic, the non-aqueous conductive liquid comprises from 1 weight % to 6 weight % of water.