Variable focus liquid lens module using direct current electromagnetic driving

The research was to develop a variable focus liquid lens module with a direct current electromagnetic driving. The variable focus lens module consists of a sandwich like structure and an electromagnetic driving device. The module was composed by three acrylic plates by milling machine and coated PDMS film as a fluidic chamber. Three acrylic plates were clipped the PDMS membrane and attached two magnets on both sides. After filling DI water in the chamber, the magnets were driven by a direct current coil to control the pressure on the PDMS membrane chamber. The pressure difference may result in the PDMS lens membrane deformation. The focal length can be changed through the pressure difference. The variable focus liquid lens with a 3 mm diameter and the focus length ranged between 28.5-4.8 mm can be driven by the direct current 0.25-3A. This study achieved the DC electromagnetic driving the membrane for variable lens module, investigated the supplied current related to focal length, and combined the CMOS image sensor for a lens system module. It proved the feasibility for variable focus lens module fabrication.