3-D Spatial Optical Crosstalk Characterization of Mini-LED Array by Hyperspectral Imaging and Spectrum-Based Ray Tracing

In micro-/mini-light-emitting diode (Micro-/Mini-LED) displays, optical crosstalk among chips is a critical issue. The precise optical crosstalk characterization of LED arrays is essential for designing high-contrast ratio optical crosstalk-free displays. In this study, we proposed a spectrum-based Monte Carlo ray tracing model to analyze the 3-D spatial optical crosstalk of the RGB mini-LED array. The model is based on the 2-D surface spectral distribution acquired by microscopic hyperspectral imaging (mu-HSI) and validated by a spectral goniometer with a maximum deviation of less than 8.61%. Combining with a microintegrating sphere array (mu-ISA), the 2-D optical crosstalk-free spectral distribution of the RGB Mini-LED array is imported to create the ray tracing model. In addition to the conventional light intensity distribution, color purity distribution and optical crosstalk at arbitrary spatial position can also be deduced. A pinhole-masked fiber spectrometer is used to verify the accuracy of the Monte Carlo ray tracing with a maximum deviation of less than 8.30%. The results indicate the great potential of spectrum-based Monte Carlo ray tracing in the designing of high-resolution microsized LED displays.