Thermal Defocus

By Scott Sparrold

Temperature variations will cause a lens or optical system to go out of focus. If an imaging system is not properly designed, it will have degraded optical performance with temperature changes (such as a loss in MTF). This web tutorial provides the background equations and descriptions. It will culminate with a method to design a passively athermal, color corrected lens mounted in a housing:
 => Color corrected (achromat) and Passively athermal! 
Editorial: Who is responsible for this work:The lens designer or the Opto-mech engineer?