The use of laser scanning confocal microscopy (LSCM) to measure flake gaps in paint systems.
Publication Date: 2016-Apr-22
The IP.com Prior Art Database
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The use of laser scanning confocal microscopy (LSCM) to quantify flake gaps in silver metallic paints
The microstructure of a silver metallic paint systems directly affects the appearance of the paint. The final microstructure of the basecoat paint layer that contains aluminum flakes is dependent on a range of formulation and application factors such as platelet size, thickness, volume fraction, bell speed, fluid flow, and booth temperature, just to name a few. In many cases, the appearance of a silver metallic paint can change from part‐to‐part, without any obvious cause. These part‐to‐part variations create "color harmony" defects, which have been shown to reduce customer satisfaction and give the appearance of poor manufacturing quality.
Laser scanning confocal microscopy (LSCM) is one method that can be used to examine the microstructure of the flakes contained within a silver metallic paint. Workers have used this technique to quantify one important microstructural property of these paint systems, the orientation of the flakes. However, this technique can also be used to quantify another microstructural property that has not previously been reported on, but has been found to have a significant effect on the appearance of the silver metallic paint. This property is the size and frequency of the gaps between the platelets, which we have quantified and termed the "gap factor".
The gap factor can be measured directly from the LSCM data and accounts for a range of issues that can affect the gap factor quantity, such as the size of individual gaps, the frequency of gaps, and the exposure of the gaps to incoming light. An example LSCM scan is shown below in Figure 1, where we
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Figure 1: LSCM scan of a typical silver metallic paint system. The dotted line represents where a 2D line scan is taken and used to calculate the gap factor of this paint system.
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utilize a line scan to extract the necessary data for analysis.
The line scan obtained from the data presented in Figure 1 is shown below in Figure 2a. Contained within this 2D height data are surface roughness and orientation variations as well as height gaps between the platelets. These features are highlighted in Figure 2a as well. To filter out the small roughness variations and quantify the larger flake gaps, the slope of the line scan was plotted vs. the line scan position in Figure 2b. ...