Enhancing the chroma of pigmented polymers using antireflective surface structures

Clausen, Jeppe Sandvik; Christiansen, Alexander Bruun; Mortensen, N. Asger

doi:10.1364/ao.52.007832

Cited by 3 publications

(1 citation statement)

References 19 publications

(23 reference statements)

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“…This perceptual illusion is similar to the well-studied Adelson's checker-shadow [72], in which the context around a grey square greatly influences our perception of its brightness. Furthermore, anti-reflective surface features have been shown to enhance the brilliance and saturation of pigmentary colours in snapdragons ( Antirrhinum majus [57]) and plastic polymers [73]. Super black surrounding or adjacent to bright colour would have the same chromatic effect.…”

Section: Discussionmentioning

confidence: 99%

Structurally assisted super black in colourful peacock spiders

McCoy

Mandsberg

et al. 2019

Proc. R. Soc. B.

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Male peacock spiders ( Maratus , Salticidae) compete to attract female mates using elaborate, sexually selected displays. They evolved both brilliant colour and velvety black. Here, we use scanning electron microscopy, hyperspectral imaging and finite-difference time-domain optical modelling to investigate the deep black surfaces of peacock spiders. We found that super black regions reflect less than 0.5% of light (for a 30° collection angle) in Maratus speciosus (0.44%) and Maratus karrie (0.35%) owing to microscale structures. Both species evolved unusually high, tightly packed cuticular bumps (microlens arrays), and M. karrie has an additional dense covering of black brush-like scales atop the cuticle. Our optical models show that the radius and height of spider microlenses achieve a balance between (i) decreased surface reflectance and (ii) enhanced melanin absorption (through multiple scattering, diffraction out of the acceptance cone of female eyes and increased path length of light through absorbing melanin pigments). The birds of paradise (Paradiseidae), ecological analogues of peacock spiders, also evolved super black near bright colour patches. Super black locally eliminates white specular highlights, reference points used to calibrate colour perception, making nearby colours appear brighter, even luminous, to vertebrates. We propose that this pre-existing, qualitative sensory experience—‘sensory bias’—is also found in spiders, leading to the convergent evolution of super black for mating displays in jumping spiders.

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Section: Discussionmentioning

confidence: 99%

Structurally assisted super black in colourful peacock spiders

McCoy

Mandsberg

et al. 2019

Proc. R. Soc. B.

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Injection moulding antireflective nanostructures

Christiansen

Clausen

Mortensen

2014

Microelectronic Engineering

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Influence of the Mold Temperature and Part Thickness on the Replication Quality and Molecular Orientation in Compression Injection Molding of Polystyrene

Roth

Zhou

Drummer

2019

International Polymer Processing

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It is well known that the process of injection molding with dynamic mold temperature control leads to a good replication quality of high aspect ratio microstructures. However, the inhomogeneous pressure distribution during the holding pressure phase results in an anisotropy of the component properties, low dimensional accuracy and, especially with optical polymers, in undesired stress birefringence. The anisotropy is based on the orientation of the molecular chains in the flow direction, which can be reduced by an injection-compression molding (ICM) process. In order to use the synergy from both processes, an injection-compression molding process with dynamic mold temperature control can be utilized. Within the scope of this investigation, the new process was reproduced by an ICM process at elevated mold temperature (ICM_EMT) and compared with injection molding (IM) with regard to molding accuracy and optical properties in dependence of component thickness and mold temperature. In order to evaluate the molding accuracy, the roughness of a wire-eroded microstructure on the cavity surface was measured. To determine the degree of orientation, the optical properties considered were the transmission and the path difference. It was shown that the adapted ICM process was able to achieve a high degree of replication accuracy with a low degree of orientation, especially for thin-walled components. ICM at elevated mold temperature reduced the path difference in the components with the lowest wall thickness by a factor of two while at the same time optimizing the replication of the microstructure. This could also be confirmed by transmission measurements.

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Enhancing the chroma of pigmented polymers using antireflective surface structures

Cited by 3 publications

References 19 publications

Structurally assisted super black in colourful peacock spiders

Structurally assisted super black in colourful peacock spiders

Injection moulding antireflective nanostructures

Influence of the Mold Temperature and Part Thickness on the Replication Quality and Molecular Orientation in Compression Injection Molding of Polystyrene

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