Short focal length lens array based on liquid crystal material with large Δn

In order to reduce the focal length of liquid crystal lens without changing the aperture, a short focal length lens array based on liquid crystal material with large An is proposed. The liquid crystal layer accumulates large optical path difference under low driving voltage because of the use of the liquid crystal material with large Δn. The bottom substrate adopts the structure of alternating I TO driving electrode and ITO grounding electrode, and the ITO driving electrode is located above the dielectric layer. The ITO grounding electrode causes a weak electric field in its edges, the dielectric layer smooths the electric field in the liquid crystal layer. This design not only realizes the parabolic phase distribution in the large aperture range, but also reduces the driving voltage. The simulation re-suits show that when the driving voltage is 6 V, the phase distribution of the liquid crystal lens array matches well with the ideal parabola. The phase difference between the center and edge of individual liquid crystal lens is approximately 42. 17π, which results in a minimum focal length of about 1.72 mm. With the driving voltage increasing from 0 V to 6 V. the focal length of the liquid crystal lens ar- ray decreases from ∞ to about 1.72 mm. Therefore, the proposed liquid crystal lens array can be used in many application areas, such as 21D/3D switchable display, and AR display.