Iris Fluorescence Biometric Recognition Device

The patent changes the parameter of illumination wavelength to excite fluorescence specifically from the iris tissue. By using wavelengths that excite endogenous fluorophores in the iris (such as tryptophan-containing proteins), the system obtains a fluorescence signature that is intrinsic to the iris biology and cannot be replicated by cosmetic lenses, thereby resolving the reliability issue without requiring complex additional hardware beyond standard fluorescence imaging capabilities.

The patent introduces fluorescence imaging as an intermediary step between conventional iris capture and recognition. Instead of directly imaging reflected light from the iris surface (which can be spoofed), the system uses fluorescence excitation and detection as a mediating process that penetrates through the iris to capture patterns from deeper tissue layers, creating an intermediate representation that is resistant to lens-based fraud.

The patent employs periodic pulsed illumination rather than continuous lighting to excite fluorescence. By delivering illumination in short, periodic pulses synchronized with the camera exposure timing, the system achieves sufficient fluorescence excitation for precise detection while minimizing total energy exposure to the eye. The pulsed nature allows the eye's photoreceptors and protective mechanisms time to recover between pulses, reducing cumulative damage risk.

The patent uses extremely short-duration illumination pulses (nanosecond or picosecond scale) to rush through the fluorescence excitation process quickly. This brief exposure duration is sufficient to excite the fluorophores and capture the emitted fluorescence signal, but too short to cause significant thermal or photochemical damage to ocular tissues. The system skips over the potentially harmful prolonged exposure period by completing the measurement in a rapid pulse.