Color Difference and Thermal Stability of Flexible Transparent InGaN/GaN Multiple Quantum Wells Mini-LED Arrays

We present studies of the color uniformity and thermal stability of a flexible and transparent 32 x 32 mini-LED array on polyethylene terephthalate (PET) substrate up to a brightness rating of 5000 nits at room temperature, whose brightness is required for outdoor display applications. Surprisingly, even at 5000 nits, the temperature variation on the surface of the LED array is less than 9 degrees C, despite the relatively low thermal diffusivity of the polymer substrates. The average surface temperature was 33 degrees C. This indicates that the heat dissipation of the fabricated LED array is superior with even a polymer substrate. Further, the narrow electroluminescent (EL) emissions from the mini-LED array help to realize wider color gamut than Rec. 2020 color gamut in display applications. The color differences from the EL spectra were calculated at three different brightness. The calculated values are far less than the color discrimination threshold of the human eye corresponding to 0.005 at all testing brightness and meet the display industry requirement for color difference.