Introduction of Multiwavelength Pills Detection In-Line Process

This review explores the development and implementation of a non-destructive, in-line, dynamic pharmaceutical inspection system utilizing carbon nanotube (CNT) film-based photo-thermoelectric (PTE) imagers operating across the ultrabroadband sub-terahertz (sub-THz) to infrared (IR) spectrum. Traditional inspection techniques in pharmaceutical manufacturing often suffer from limited penetration depth, destructive sampling, and reduced detection accuracy. The presented ultrabroadband optical monitoring approach addresses these challenges by enabling label-free, non-contact identification of impurities, coating irregularities, and compositional variations within pharmaceutical pills. The system employs sub-THz, long-wave infrared (LWIR), and short-wave infrared (SWIR) radiation bands, combined with CNT PTE imagers that offer high sensitivity, mechanical flexibility, and room-temperature operation. Through transmissive and reflective imaging configurations, the system captures detailed optical signatures of pharmaceutical agents, identifying both internal and surface defects in real time. Experimental results demonstrate effective differentiation of various drug compositions and concealed impurities such as metal, glass, and plastic inclusions. The integration of automated optical stages and high-speed data acquisition enables scalable, continuous monitoring suitable for industrial environments. This review highlights the significance of ultrabroadband CNT-based PTE imaging as a promising solution for advancing pharmaceutical quality assurance, combining high accuracy, rapid inspection, and non-invasive operation