Cognex Corporation
Systems and methods reduce temperature induced drift effects on a liquid lens

Abstract:

Systems and methods reduce temperature induced drift effects on a liquid lens used in a vision system. A feedback loop receives a temperature value from a temperature sensor, and based on the received temperature value, controls a power to the heating element based on a difference between the measured temperature of the liquid lens and a predetermined control temperature to maintain the temperature value within a predetermined control temperature range to reduce the effects of drift. A processor can also control a bias signal applied to the lens or a lens actuator to control temperature variations and the associated induced drift effects. An image sharpness can also be determined over a series of images, alone or in combination with controlling the temperature of the liquid lens, to adjust a focal distance of the lens.