近红外无创生化分析中, 要获得准确的血液生化成分信息, 需要非常高的系统信噪比。 为提高分析系统的信噪比, 开展了以增大系统光能利用率为目标的高效双复合抛物面聚光(DCPC)系统研究。 首先, 针对近红外无创生化分析中光学系统集光要求, 研究了复合抛物面聚光器(CPC)出射光特点, 确定出一级CPC最大聚光角范围。 然后, 通过比较标准型和截短型DCPC光能利用率变化, 优化出最佳结构参数。 最后, 结合皮肤组织光学参数, 计算了入射光波长为1 000 nm时, DCPC系统、 CPC-聚焦反射镜系统以及无光学收集系统的光能利用率。 结果显示, 三种系统的光能利用率分别为1.46%, 0.84%, 0.26%。 设计的DCPC系统增强了对人体漫反射光的收集能力, 可有效提高无创生化分析系统的信噪比及整体分析精度。

High signal-to-noise ratio (SNR) of system is necessary to obtain accurate blood components in near infrared noninvasive biochemical analysis. In order to improve SNR of analytical system, high-efficiency double compound parabolic concentrator (DCPC) system was researched, which was aimed at increasing light utilization efficiency. Firstly, with the request of collection efficiency in near infrared noninvasive biochemical analysis, the characteristic of emergent rays through compound parabolic concentrator (CPC) was analyzed. Then the maximum focusing angle range of the first stage CPC was determined. Secondly, the light utilization efficiency of truncated type was compared with standard DCPC, thus the best structure parameters of DCPC system were optimized. Lastly, combined with optical parameters of skin tissue, calculations were operated when incident wavelength is 1 000 nm. The light utilization efficiency of DCPC system, CPC-focusing mirror system, and non-optical collecting system was calculated. The results show that the light utilization efficiency of the three optical systems is 1.46%, 0.84% and 0.26% respectively. So DCPC system enhances collecting ability for human diffuse reflection light, and helps improve SNR of noninvasive biochemical analysis system and overall analysis accuracy effectively.