Optical analysis of coatings including diffractive pigments using a high-resolution gonioreflectometer

Filip, Jiřı́; Vávra, Radomír; Maile, Frank J.

doi:10.1007/s11998-018-0137-5

Cited by 7 publications

(6 citation statements)

References 24 publications

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“…Therefore, it is essential to investigate the effect of incident angle on the interaction between the laser beam and the CF/PEEK composite. Gonioreflectometer measurements could be carried out to investigate the reflection intensity distribution from non-homogeneous surfaces [ 25 , 32 , 33 ], such as the tapes considered in this study. Understanding the complex relationship between fiber orientation, incident angle, and non-specular reflection patterns is crucial.…”

Section: Methodsmentioning

confidence: 99%

Influence of Curvature Feature on Laser Heating during Tape Placement Process for Carbon Fiber Reinforced Polyether Ether Ketone Composite

Liu

Huan

et al. 2023

Polymers

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The curvature feature makes the irradiance and absorptivity change, resulting in an uneven power density distribution, which affects the quality of composite parts. In this study, a theoretical model-based Super-Gaussian profile beam in the laser irradiation area was established to obtain the heat flux distribution on the curved surface. The effect of curvature on the surface scattering reflection, temperature distribution, and surface morphology were investigated and verified the validity of the theoretical model. Furthermore, the influence of the laser intensity distribution, laser inclination and curvature radius on the power density distribution and distribution uniformity were studied. Research indicated that the power density increases as the distance from the origin increase resulting from the variation of the irradiance and absorptance along the circumference. The flatter the intensity distribution of the laser beam in the height direction, the less uniform the power density distribution. Accordingly, the typical Gaussian profile beam significantly ameliorates the power density distribution. This research provides a novel understanding of using heat sources during laser heating thermoplastic tape placement.

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Section: Methodsmentioning

confidence: 99%

Influence of Curvature Feature on Laser Heating during Tape Placement Process for Carbon Fiber Reinforced Polyether Ether Ketone Composite

Liu

Huan

et al. 2023

Polymers

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“…Therefore, the CIE technical committee is currently discussing the measurement and evaluation algorithms in detail 24,25 . In addition, various studies have analyzed the sparkle of the surface coatings 8‐18 . The spatial frequency characteristics were used to evaluate sparkle in this study.…”

Section: Evaluation Of the Coating Appearancementioning

confidence: 99%

“…Therefore, it is important to measure and evaluate these coatings at multiple angles. As a result, various methods 14‐18 and commercial devices 19,20 have been developed to evaluate the color and sparkle of these coatings at different observation angles. Burgos‐Fernández et al constructed a gonio‐hyperspectral imaging system and analyzed the characteristics of various coatings by extending spectral verification to infrared 14 .…”

Section: Introductionmentioning

confidence: 99%

“…Burgos‐Fernández et al constructed a gonio‐hyperspectral imaging system and analyzed the characteristics of various coatings by extending spectral verification to infrared 14 . In addition, Filip et al measured the coating sample using a gonio‐reflectometer with flexible measurement geometry and analyzed the orientation of the flakes contained in the coating 18 …”

Section: Introductionmentioning

confidence: 99%

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Multi‐angle measurement device for analysis of coating appearances

Watanabe

2021

Color Research & Application

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Material appearance is an important factor in product design because it tends to attract consumers. Effect coatings that contain aluminum and interference pigments are widely used in automobiles. The color and sparkle values of these coatings vary with the observation angle. Several methods have been proposed to study these variations with respect to the observation angle. However, a high angular resolution is required to understand human perception. Thus, we developed a measurement device that can analyze the color and sparkle values at a high angular resolution for multiple angles. The device captures the sample surface by using a line scan spectral camera. Because the lighting device rotates around the sample while the line scan camera is capturing images, each scan line that makes up the image contains different angle information. A comparison was performed among the results obtained from this study, a commercially available device, and a subjective value of sparkle perception. Twenty samples were required to confirm that the sparkle values calculated from this study correlated closely with the subjective scores. In addition, the difference between the color values obtained from the BYK‐mac i spectrophotometer and the proposed technique was less than 3.5 (ΔE00). The findings of this study will help in developing the appearance of effective coatings. In addition, using evaluation values, quality control, and improvement are possible after mass production of coatings.

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“…Since the deflection depends on the wavelength, the color at a given observation direction depends on the deflection angle with respect to the normal direction to the pigment. In coatings based on diffraction pigments, the color shift reveals very clearly when varying the aspecular angle at a constant incidence angle [2,[15][16][17]31]. An example of this color shift with the geometry is shown as a CIE a*b* diagram in Figure 2, for one of the highly goniochromatic diffraction-based special effect coating studied in Reference [15] (SpectraFlair R Silver 1500-14).…”

Section: Introductionmentioning

confidence: 99%

Angular and Spectral Bandwidth Considerations in BRDF Measurements of Interference- and Diffraction-Based Coatings

Ferrero

Campos

2020

Coatings

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The Bidirectional Reflectance Distribution Function (BRDF) of iridescent (or goniochromatic) surfaces may vary notably with both spectral and angular variables, and, therefore, finite spectral bandwidth and collection solid angles inherent to any measuring instrument introduce a deviation from the correct value. Experimental data of highly goniochromatic samples are used to analyse their impact on measurement uncertainty. The results indicate that it is advisable to standardize spectral and angular bandwidths because the systematic error is not negligible for typical measuring systems. The 95th percentile of the error distribution of the measurement of the BRDF due to these finite bandwidths, and also the 95th percentile of the calculated resulting color differences, are used as criteria to establish recommended values of spectral and angular bandwidths. The impact of the bandwidth is more critical in the measurement of the BRDF of diffraction-based than of interference-based coatings.

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Optical analysis of coatings including diffractive pigments using a high-resolution gonioreflectometer

Cited by 7 publications

References 24 publications

Influence of Curvature Feature on Laser Heating during Tape Placement Process for Carbon Fiber Reinforced Polyether Ether Ketone Composite

Influence of Curvature Feature on Laser Heating during Tape Placement Process for Carbon Fiber Reinforced Polyether Ether Ketone Composite

Multi‐angle measurement device for analysis of coating appearances

Angular and Spectral Bandwidth Considerations in BRDF Measurements of Interference- and Diffraction-Based Coatings

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