With the electric field varying properly in space, liquid crystal directors at different positions orient accordingly, thus forming a lens shape like gradient refractive index (GRIN) profile to converge the light beam to a specific point. In this study, we will use multiple ring electrodes on one glass substrate and another glass plate with conductive layer (counter glass) to enclose the LCs. With different voltages applied to these ring electrodes, gradient refractive index appears within the device, and converge the light. Another approach is to use a ring like high resistive layer between the two conductive ring electrodes to form a voltage drop instead of multiple electrodes within one pitch, which can largely simplify the driving circuits and device structures.
Fig.1 Cross-section of the proposed liquid crystal lens: (a) LC lens with multiple ring electrodes; (b) LC lens with a ring like high resistive layer between two conductive ring electrodes;
In this study, two approaches are adopted to fabricate the GRIN liquid crystal lenses: multiple ring electrodes with different voltages and a ring like high resistive layer with two terminal voltages within one pitch. Each of them is assembled with conductive counter glass to form the liquid crystal lens; Several masks with various electrode widths and spacings, will be designed for the device fabrications, as well as simulations; Different liquid crystal materials including blue phase will be filled into the devices and optical characterizations will be studied in detail with different driving schemes.
Liquid crystal lens, gradient refractive index, high resistive layer, light beam steering.Ardoyen CMST + at home.