Double-layer liquid crystal lens device

The invention provides a double-layer liquid crystal lens device which is provided with two liquid crystal lens structures, wherein each liquid crystal lens structure can control the voltage of the structure through arranging active components on the liquid crystal lens structure. When the incident light rays pass through the liquid crystal lens structures in order, the liquid crystal lens structures can compensate the optical path differences of the incident light rays, so that the double-layer liquid crystal lens device still has a good focusing function without using a polaroid and is less likely to produce two focuses. Besides, the driving voltage applied to each active component can be properly controlled so as to control the turning of the liquid crystal molecules in the liquid crystal lens structures, and each liquid crystal lens structure in the double-layer liquid crystal lens device can present a refractive index distribution similar to the graded reflective index lens, thus the device has a focusing function similar to the light focusing/divergence of the convex/concave lens.