Novel metal-dielectric metameric optical filters for optical security devices

• Published in: Optoelectronics letters Vol. 10; no. 6; pp. 411 - 414
• Main Author: 郭榕 陈楠 陈鹭剑 王晓忠 蔡志平 李延凯 卜轶坤
• Format: Journal Article
• Language: English
• Published: Heidelberg Tianjin University of Technology 01.11.2014
• Subjects: Lasers; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy; 光学滤光片; 同分异构; 同色异谱; 多层系统; 多层结构; 安全设备; 电介质; 金属; Color Difference; Correlate Color Temperature; Thickness Deviation; Color Shift; Color Target
• ISSN: 1673-1905; 1993-5013
• DOI: 10.1007/s11801-014-4150-3

Optical security devices play an essential role in the fight against counterfeiting. In this paper, we study and design a pair of metal-dielectric optical filters based on metameric effect, which offer a hidden image effect by the color shift at a specific angle of observation. Compared with all-dielectric multilayer system, the metal-dielectric multilayer structure has larger color shift with varying incident angle, higher color saturation and fewer layers. Finally, the stacks with 5 layers and 7 layers are achieved, and the color difference index is only 0.71, which shows good metameric matching effect. Simultaneously, the sensitivity of filters to deposition errors is analyzed when the thickness deviation is ±2%, and the results show that the two filters have good manufacturability.