通常测色分光光度计均由两个独立且完全相同的分光系统组成,为实现测色分光光度计小型化、轻量化,提出一种双光束分光系统设计.将传统的分光系统进行改进,使一个分光系统实现双光束分光系统的功能,用两个小狭缝代替一个狭缝,即可实现两束光谱同时探测.分析了双光束分光系统的工作原理及设计要求,设计了一个用于便携式测色分光光度计的分光系统.设计的Czerny-Turner结构双光束分光系统采用超环面成像镜,可以较好的校正像散,防止两束光谱串扰,两束光谱在探测器上完全没有重叠,光谱分辨率小于10 nm,谱面长度9.12 mm,体积仅为57 mm×54 mm×23 mm,满足设计指标要求.通过与相同设计指标的单光束分光系统比较得出,采用双光束分光系统的改进型测色分光光度计比传统的测色分光光度计减少了一整套分光系统,从而使体积大幅缩小.该方法特别适用于便携式测色分光光度计,也可适用于其他双光束分光光度计。

Spectrophotometers for colorimetry are usually composed of two independent and identical spectrometers.In order to reduce the volume of spectrophotometer for colorimetry,a design method of double-beam spectrometer is put forward.A traditional spectrometer is modified so that a new spectrometer can realize the function of double spectrometers,which is especially suitable for portable instruments.One slit is replaced by the double-slit,than two beams of spectrum can be detected.The working principle and design requirement of double-beam spectrometer are described.A spectrometer of portable spectrophotometer is designed by this method.A toroidal imaging mirror is used for the Czerny-Turner double-beam spectrometer in this paper,which can better correct astigmatism,and prevent the dual-beam spectral crosstalk.The results demonstrate that the double-beam spectrometer designed by this method meets the design specifications,with the spectral resolution less than 10 nm,the spectral length of 9.12 mm,and the volume of 57 mm×54 mm×23 mm,and without the dual-beam spectral overlap in the detector either.Comparing with a traditional spectrophotometer,the modified spectrophotometer uses a set of double-beam spectrometer instead of two sets of spectrometers,which can greatly reduce the volume.This design method can be specially applied in portable spectrophotometers,also can be widely applied in other double-beam spectrophotometers,which offers a new idea for the design of dual-beam spectrophotometers.