Printed ZnS Security Feature for Deep Red Luminescence Detection

The patent changes the crystalline structure parameters of ZnS from purely cubic to a mixture of cubic and hexagonal phases, and modifies the dopant composition by introducing Co alongside Cu. This parameter change resolves the contradiction by achieving reliable deep red luminescence with high efficiency while providing a clear manufacturing pathway through controlled annealing processes that favor the formation of specific phase fractions and dopant distributions.

The patent creates a composite luminophore material combining ZnS matrix with Cu and Co dopants, and incorporating both cubic and hexagonal crystalline phases. This composite approach resolves the reliability-efficiency contradiction by leveraging the synergistic effects of multiple dopants and phases to achieve stable, high-efficiency deep red electroluminescence that is difficult to replicate with single-phase or single-dopant systems.

The patent introduces thermoluminescence and optically stimulated luminescence as intermediary detection mechanisms. Instead of directly detecting electroluminescence which requires complex high-frequency electric field equipment, the security feature can be verified through thermal or optical stimulation that releases stored energy in a manner detectable by simpler devices. This intermediary approach maintains measurement precision while reducing detection system complexity.

The patent replaces the mechanical/electrical detection system (high-frequency electric fields) with optical and thermal detection systems. By substituting the excitation and detection mechanisms, the patent enables authentication through simpler optical scanners or thermal devices rather than complex electroluminescence testing equipment, thus reducing device complexity while maintaining verification accuracy.

The patent develops a composite dopant system combining Cu and Co within the ZnS matrix. This composite doping approach resolves the contradiction by using Co to stabilize the crystal structure and prevent degradation pathways that limit Cu-only systems. The synergistic interaction between Cu (providing deep red emission) and Co (providing structural stability) enables both high illumination intensity and improved aging resistance simultaneously.

The patent modifies the compositional parameters by introducing Co dopants at specific concentrations alongside Cu, and controls the phase composition parameters to achieve optimal cubic/hexagonal ratios. These parameter changes resolve the contradiction by creating a chemically stable structure that maintains deep red luminescence intensity while resisting aging effects through the stabilizing influence of Co and controlled phase distribution.