新型紫外光致发光图像高速采集装置的研制及其在筛分天然钻石中的应用

Development of a new ultraviolet photoluminescence image high-speed acquisition device and its application in screening natural diamonds

为了提高批量小颗粒钻石的筛查效率和准确性,研制了一种新型紫外光致发光图像高速采集装置——珠宝首饰观察鉴定仪(DDO),通过对激发光波长、工业相机等的选用和结构设计技术突破,以及对发光现象采集方式进行创新,实现了批量观察不同宝石间的光致发光现象和发光延迟现象差异等,从而实现对宝石高效检测。对20 000粒以上无色天然钻石、合成钻石和钻石相似品进行的DDO测试结果表明,98%~99%的无色天然钻石在紫外光激发光停止后的0.1~10 ms内可观察到的碧蓝色磷光现象,为天然钻石典型特征,合成钻石和其他无色宝石的发光特征(发光颜色、强度、持续时间、结构分区)明显区别于天然钻石,由此建立了一种通过观测包括荧光、衰减时间在100 ms内的连续发光(磷光)特征差异性作为筛分条件快速、准确筛分无色天然钻石的新方法。本装置提高了钻石鉴定的准确度和检测效率,对天然钻石的筛查通过率可高达99%,对合成钻石和仿钻石的筛查准确性可达100%。

In order to improve the screening efficiency and accuracy of batch small particle diamonds,this paper developed a new type of ultraviolet photoluminescence image high-speed acquisition devicejewelry observation and identification instrument(DDO).Through the selection of excitation light source,industrial camera,structural design technology breakthroughs,and innovation in the collection method of luminescence phenomena,it achieved batch observation of photoluminescence phenomena and luminescence delay differences between different gem-stones,thereby achieving efficient detection of gemstones.The DDO test results on over 20000 colorless natural diamonds,synthetic diamonds,and imitation diamonds show that 98%to 99%of colorless natural diamonds exhibit a blue phosphorescence phenomenon within 0.1~10 ms after the cessation of ultraviolet light excitation,which is a typical feature of natural diamonds.The luminescence characteristics(luminescence color,intensity,duration,structural zoning)of synthetic diamonds and other colorless gemstones are significantly different from natural diamonds.Therefore,a new method for rapid and accurate screening of colorless natural diamonds is established by observing the differences in continuous luminescence(phosphorescence)characteristics,including fluorescence and decay time within 100 ms,as screening conditions.This device improves the accuracy and detection efficiency of diamond i-dentification,with a screening pass rate of up to 99%for natural diamonds and 100%for synthetic and imitation diamonds.