Fig. 4From: Controllable liquid colour-changing lenses with microfluidic channels for vision protection, camouflage and optical filtering based on soft lithography fabricationColour-changing glasses for vision protection. a Colouration photographs with or without colour liquids. b The transmittance of PDMS films with different thickness at different temperature (top) and transmittance of the colour-changing lenses filled with different Fe2(SO4)3 solutions (bottom)Back to article page