Tunable liquid lens with reduced aberration

An imaging device comprising:

• an image sensor;
• a liquid crystal layer;
• an electric field source providing a variable, spatially non-uniform electric field across the liquid crystal layer to provide a tunable range of optical power, wherein said layer, under the effect of said electric field, forms a tunable liquid crystal lens having a variable optical power that changes in a first direction with an increase in the strength of the electric field from an initial optical power to a peak optical power, and which changes in a second direction with a further increase of the strength of the electric field from said peak optical power to a non-zero end optical power different from the initial optical power, and wherein operation of the liquid crystal layer is limited to a continuous, non-zero tunable operational optical power range between the peak optical power and the end optical power;
• and
• one or more fixed lenses cooperating with said liquid crystal lens at non-zero optical power to focus an image onto said image sensor with an infinity focus near one limit of said tunable range.

A method of controlling a tunable optical device having a liquid crystal layer and a variable, spatially non-uniform electric field applied across the liquid crystal layer to provide a tunable range of an optical property, the method comprising:

• detecting at least one of aberration and scattering caused by said liquid crystal layer under conditions of relatively low electric fields and determining a corresponding optical quality of said device as a function of electric field;
• determining a preferred range of operation for said electric field that avoids a range at which said optical quality is less desirable;
• and
• generating said electric field in accordance with a desired optical value for said device within said preferred range of operation.