基于近红外光谱的人眼像差校正系统中变形镜性能对比研究

对比分析了基于近红外光谱的人眼像差校正系统中两种微机械薄膜变形镜(OKO37单元和BMC140单元)的结构特征和空间特性,着重对变形镜的影响函数进行了主成分研究,建立了变形镜电压控制模型,并通过调整参数d确定变形镜最优控制模式。最后对Zernike单位模式波前像差和Thibos模式人眼波前像差进行拟合仿真实验,结果表明BMC140单元变形镜对Zernike各阶模式的拟合能力均为OKO37单元变形镜的2倍以上。对RMS均值为0.683λ(λ=0.785μm)的Thibos模式人眼像差,BMC变形镜校正后残余像差RMS值为0.063λ,达到了光学系统的衍射极限(λ/14)。而OKO变形镜由于受相邻电极交连值大、电极分布密度小等因素的影响,其校正能力不及BMC变形镜,残余像差RMS值为0.168λ。本方法也可用于其他种类变形镜的性能评估。

Comparative Study on the Performance of Deformable Mirror of NIR Based Human Eye Aberration Correction System

The structure features and spatial characteristics of the two kinds of micro-machined membrane deformable mirrors,OKO 37-element and BMC 140-element,which work in the NIR based human eye aberration correction system,are compared and analyzed.At same time,the principal component analysis was carried out for the influence function of the mirror,the voltage control model was established and the optimal control mode of deformable mirror can be determined by adjusting the control parameter d.Finally,the simulation experiments for fitting aberration of unit Zernike mode and human eye aberration of Thibos model were carried out.The experiment results show that the capability for fitting the each Zernike mode of BMC 140-element mirror is twice more than the OKO 37-element mirror at least.When correcting the Thibos model human eye aberration whose average RMS error is 0.638λ(λ=0.785 μm),the residual RMS error of BMC mirror is 0.063λ which achieves the diffraction limit(λ/14) of the optical system,but the correction capability of OKO mirror is far less than BMC mirror due to the large cross-linked value between actuators,small density distribution of actuators and some other influencing factors,and the residual wave-front RMS error is 0.168λ.The methodology can also be used for other types of deformable mirror performance evaluation.