Patent ID: 7612947

Claim:
A controllable optical lens system, comprising: a lens ( 30 ) comprising: a chamber housing first and second fluids ( 10 , 12 ), the interface between the fluids defining a lens surface ( 15 ); and an electrode arrangement ( 14 , 16 ) for electrically controlling the shape of the lens surface; a sensor arrangement ( 34 ) for detecting a condition of the lens and/or an environmental condition and for generating a focus error signal ( 35 ) that represents a focus error of the lens at a specific moment in time; an autofocus control feedback loop ( 42 ) for converting the focus error signal ( 35 ) output from the sensor arrangement ( 34 ) into an electrode arrangement drive signal to optimize lens characteristics by taking account of changes in said lens characteristics over time and to changes in external conditions over time, the feedback control loop implementing an autofocus function ( 36 ) for ensuring the correct lens focus for all operating conditions of the lens; a variable gain element ( 44 ) outputting the lens driver signal; and a gain adjustment unit ( 46 ) for controlling the variable gain element ( 44 ) based on the sensor arrangement ( 34 ) output.