Multi-Layer Optical Element for Anti-Counterfeiting via Total Internal Reflection

The optical element is divided into multiple functional layers: a first layer with a first relief structure for total internal reflection, a second layer with a second relief structure for diffraction/reflection, and a third layer with a third relief structure for additional optical effects. Each layer operates independently to provide specific optical functions, creating a multi-layered security system that is difficult to replicate while maintaining manageable complexity through modular design.

The patent employs composite optical structures combining different relief structure types (first, second, and third relief structures) with varying optical properties. The first relief structure utilizes total internal reflection, the second provides diffraction and reflection, and the third adds additional optical effects. This composite approach creates a synergistic security system where the combination of different optical mechanisms provides enhanced counterfeit prevention capability.

Different regions of the optical element have different optical properties tailored to specific observation angles. The first relief structure is optimized for total internal reflection at specific angles, while the second and third relief structures provide different optical effects at other angles. This local optimization ensures that each region maintains its intended optical function across the desired observation angle range, balancing contrast and transparency requirements.

The optical element dynamically changes its optical properties based on the observation angle. As light incident angle changes, the different relief structures activate different optical mechanisms: total internal reflection, diffraction, and reflection. This dynamic behavior allows the element to provide high contrast at certain angles while maintaining transparency at others, adapting its optical characteristics to the viewing conditions.

The optical element segments the optical effects across multiple layers and angles. While one layer may be optimized for transparency at a specific angle, other layers provide optical effects at different angles. The first relief structure provides total internal reflection at certain angles, while the second and third structures provide diffraction and reflection effects at other angles, ensuring that transparency and optical effects are both achieved through spatial and angular segmentation.

The patent transitions from a single-angle optimization to a multi-angle, multi-dimensional optical design. By incorporating multiple relief structures with different orientations and optical properties, the element creates optical effects that span multiple observation angles and dimensions. This dimensional expansion allows the element to maintain transparency in one dimension while providing strong optical effects in other dimensions, satisfying both requirements simultaneously.