The liquid lens module is an electronically controllable variable focus system.
Cognex was the first company to leverage liquid lens technology within both fixed-mount and handheld industrial barcode readers.
The liquid lens uses two iso-density liquids, oil as an insulator and water as a conductor. The variation of voltage leads to a change of curvature of the liquid-liquid interface, which in turn leads to a change of the focal length of the installed optical lens.
The following diagram shows how the liquid lens is constructed:
Advantages and Availability
The key advantages of the liquid lens are its ruggedness (no moving parts), fast response times, good optical quality, low power consumption and size.
The liquid lens can simplify installation, setup and maintenance by eliminating the need to open the reader and manually touch the lens. Relative to other autofocus mechanisms, the liquid lens has extremely fast response times. It is also ideal for applications with reading distances that change from part to part or during part changeover.
Many DataMan barcode readers take advantage of this technology. The table below outlines the DataMan optics options.