红外双波段消热差系统设计

Design of Infrared Dual-band Athermal Optical System

引入了光学材料双波段的平均规化热差系数 T,建立了在3～5μm和8～12μm两个波段上分离透镜消色差、消热差方程组。得到对该光学系统设计的材料选择具有指导作用的三维无热差图,并利用透视投影原理得到相应的投影无热差图。设计了视场4°、有效焦距61mm、F数为2.5、温度范围在-54～71℃、适用于3～5μm和8～12μm双波段的红外光学系统。该系统在3～5μm和8～12μm波段调制传递函数基本达到衍射极限,在空间频率为10lp/mm时,数值分别为0.87和0.68;当温度从-54℃变化到71℃时,数值波动不到0.01;轴向像差在-54～71℃温度范围内,最大值分别为45μm和93μm,都小于相应波段的系统焦深。因此,设计系统具有非常好的双波段消色差、消热差能力。

The mean normalized efficiency of dual-band thermal power dispersion was introduced. The equations of dual-band athermal thin lenses spaced apart were derived. The three-dimensional athermal chart was established with which the suitable materials of dual-band athermal optical system was selected. The infrared optical system operating in the 3-5 μm and 8-12 μm wavelength bands with the cold shield efficiency of 100% was designed. The designed system possesses good athermal ability with satisfactory imaging quality. It can be used for the high-resolution imaging systems of remote control equipment and monitoring devices.