Patent ID: 7423821

Claim:
An image acquisition system, comprising: a lens structure configured to project an image on an image surface of an image sensor, said lens structure comprising a compound lens, said compound lens comprising at least a first and a second lens element each comprising at least one substantially non-planar lens surface, said first and second lens elements comprising different lens materials, said first lens element is further away from said image sensor than said second lens element, said first lens element comprising a material with a higher Abbe number than said second lens element, wherein a change in an index of refraction of said second lens element is greater than a change in an index of refraction of said first lens element over a given temperature range, wherein an index of refraction of said first lens element changes more quickly as a function of temperature than an index of refraction of the second lens element thereby reducing the change in focal length of said compound lens over said given temperature range.