以平行排列液晶盒作为液晶空间光调制器的模型，求解Erickson-Leslie方程，得到相位调制量为2π时的响应时间公式。通过理论计算，作出不同电压下盒厚与响应时间的关系曲线，确定了最佳盒厚的存在，并且表明最佳盒厚与响应时间随驱动电压的增加而减小，且变化量逐渐减小；电压由5 V增至10 V时，响应时间的变化量达到最大，缩短了10.62%。实验测得三个不同厚度液晶盒的响应时间随电压的变化曲线，结果表明，驱动电压增加，响应时间缩短，在5 V增至10 V的过程中响应时间变化量与理论值接近，且电压增至15 V甚至更高电压时，响应时间基本不会再变化。此外，同一电压下，相对最佳盒厚相同厚度变化量，厚盒的响应优于薄盒。

Based on parallel-aligned liquid crystal (LC) cell, which is the prototype of LC spatial light modulator, Erickson-Leslie equation is solved, and the response formula with fixed phase retardation 2π is obtained. By theoretical calculations, the curves of relationship between cell gap and response time under various voltages are plot, the existence of optimal cell gap is ensured and the curves demonstrate that both optimal cell gap and response time decrease while applied voltage increases, and the variation is decreasing gradually; the variation of response time reaches to the maximal value: shortened by 10.62% when applied voltage changes from 5 V to 10 V. The relation curves between voltage and response time of three LC cells are measured by experiments. The results demonstrate that response time is shortened while the applied voltage increases, the variation of response time is close to theoretical value when applied voltage increases from 5 V to 10 V, and when 15 V or higher voltage is applied, response time changes little. Besides, slight thicker LC cell has better response than thinner LC cell regarding with the same variation to optimal cell gap under the same voltage.