理论上分析并从实验上验证了通过改变外加电场的频率来驱动的128×128元变焦液晶透镜阵列。将上电极设计为圆孔阵列,由于圆孔电极在单元区域内形成的非均匀电场分布,从而使液晶分子在不同位置处旋转角度不同,在液晶层内形成了折射率梯度分布,由此单元区域具有了光学聚焦特性。分析了由于外加电场频率改变引起液晶介电常数变化给液晶透镜阵列焦距带来的影响。实验中制作的液晶透镜阵列的焦距调节范围为20-600 μm,焦点尺寸为10 μm,响应时间为微秒量级,可以呈清晰的多重影像。通过使用外加电场的频率可以得到变焦液晶透镜阵列,降低了液晶透镜阵列的工作电压,提升了液晶透镜阵列工作响应速度。

A novel 128×128 elements liquid crystal lens array with tunable focal length was analyzed and fabricated by using frequency drive instead of voltage drive. The top electrode was designed as circular array electrode. As the electric field was inhomogeneous in circular unit,the rotation angle was different in liquid crystal layer. Then the gradient refractive index was formed,and the optic in the circular unit was convergent. The effect about focal length of liquid crystal lens array with different frequencies was analyzed. The focal length range of liquid crystal lens array was 20-600 μm. The focal size was 10 μm. The response time was sub-microsecond. The liquid crystal lens array driven by frequency can be got in this way. So the operating voltage of liquid crystal lens array was lower,and the response time of liquid crystal lens array was quicker.