Supreme-black levels enabled by touchproof microcavity surface texture on anti-backscatter matrix

Abstract

Emerging immersive high–dynamic range display technologies require not only high peak luminance but also true black levels with hemispherical reflectance below 0.001 (0.1%) to accommodate the wide dynamic range of the human eye (~10 5 ). Such low reflectance materials, denoted here as “supreme black,” must exhibit near-perfect surface antireflection, extremely low in-matrix backscattering, and sufficient optical thickness, which, to date, have only been achieved by fragile sparse materials. We demonstrate a record-low hemispherical reflectance below 0.0002 (absorptance above 0.9998) in a touchproof material by satisfying the three requirements with a superwavelength surface microtexture with nanolevel details, low Mie backscattering composition, and optional additional underlayer. Our supreme black finishes are one to two orders of magnitude blacker than previously developed touchproof super-black materials. Thereby, unprecedented black levels enabling an ambient contrast ratio of ≳10 4 would be provided in display devices, contributing to immersive visual experiences that are critical for seamless remote collaboration and reliable virtual health care.

Wood-based superblack

“…VACNT-based materials are fragile by nature as the adhesion of the CNT array to the underlying substrate is driven by weak secondary interactions. Moreover, the moisture sensitiveness of VACNT could potentially lead to loss of blackness 13,14 . Supreme black 14 and Ni-P coatings 5 are touch-proof and more robust than VACNT materials.…”

“…In the animal kingdom, superblack features have been used for various reasons including camouflage 6 , thermoregulation 7 , as well as to enhance conspicuousness [8][9][10] and aposematism 11 . Superblack is typically obtained by combining chemically derived blackness (arising from moieties with short optical bandgaps) with structural features that induce multiple internal light reflections and show low backscattering [12][13][14][15] .…”

“…These carbon constructs, although displaying ultralow light reflectance, lack cohesion 19,22 and are fragile 12,13,23,24 , thus imposing limitations for their application. More recently, hemispherical light reflectance levels have been lowered down to 0.02% by embedding a light absorbing polymer into a microcavity textured surface 14 . The resulting material overcomes problems related to cohesion and fragility, but it still relies on synthetic precursors.…”

Bio‐Inspired Camouflage Skin with Photonic Crystal Structure and Size‐Confinement Effect

“…[34] Thus, the ideal camouflage skin for surviving in living environments are required to possess certain essential characteristics, such as long-term environmental stability, excellent mechanical performance for adapting to large deformation, and rapidly self-adaptive camouflage capability for complex backgrounds, just like the nature organisms. [35,36] Herein, the design and development of an artificial camouflage skin with a comprehensive performance is urgent and necessary.…”

Realizing an Optical Micro‐Cavity in a CuCo2O4‐W‐CuCo2O4 Thin Film Stack for Spectrally Selective Solar Absorbers

“…Also, they can be an alternative to the nitrides [ 19 ] and oxy‐nitride coatings [ 20 ] in the multilayer absorbers because of the ease of fabrication. Recently optical micro‐cavity‐based structures have gained immense attention due to their ability to achieve and tune spectral selective absorption leading to better photovoltaic efficiency, [ 21 ] energy upconversion, [ 22 ] transparent optical devices, [ 23 ] extremely low reflectance, [ 24 ] and also new physics phenomena. [ 25 ] Quasi‐optical micro‐cavities (QOMs) are reported for their increased absorption in the solar spectrum range by modifying the optical constants of each layer.…”