Laser-Tuned Lanthanum Boride Coatings for Multicolor Watch Dials
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Solution Overview
Problem
Existing methods for producing decorative surfaces for luxury items like watches and jewelry lack the ability to create multicolored, corrosion-resistant, and abrasion-resistant surfaces efficiently.
Innovation Solution
A layer of lanthanum boride (LaBx) is deposited on a substrate using PVD and then treated with a laser to modify its stoichiometry to LaBy, changing its color based on laser parameters, thereby creating multicolored surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a layer of lanthanum boride is deposited and treated with laser to modify stoichiometry, then multicolored surfaces are produced, but the process complexity increases
Solution Approach 1:
The patent applies local quality by using laser treatment to modify the stoichiometry of lanthanum boride layer at specific locations, creating different colors in different portions of the same layer. Each treated portion has locally modified properties (different stoichiometry LaBy with y between 6-12) that determine its color, while the overall structure remains a single layered system.
2Adaptability or versatility
If laser parameters are adjusted to change stoichiometry from LaBx to LaBy, then color is determined by laser parameters, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs parameter changes by systematically varying laser treatment parameters (power, pulse duration, scanning speed, wavelength) to achieve different stoichiometries (LaBy where y ranges from 6 to 12) in the lanthanum boride layer. Each parameter combination produces a specific color, creating a controllable relationship between processing parameters and final product appearance.
3Adaptability or versatility
If the laser removes the LaBx layer at higher powers, then the substrate material color is revealed, but material loss increases
Solution Approach 1:
The patent applies partial action by using controlled laser ablation that removes the lanthanum boride layer only to the extent needed to reveal the substrate color, rather than completely removing all material. The treatment is calibrated to achieve the desired visual effect while minimizing material loss, using just enough energy to expose the substrate in targeted areas.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method produces decorative surfaces with high resistance to corrosion and abrasion, retaining sufficient hardness for horological applications while maintaining aesthetic appeal through customizable colors.
Implementation Method 1
the layer of LaBx is deposited by PVD (Physical Vapour Deposition)
Implementation Method 2
subsequently treated with a laser, so as to modify said stoichiometry of said portion of the layer of LaBx subjected to the laser treatment
Data Source
AI summary
A layer of lanthanum boride of stoichiometry LaBx where x is between 9 and 12 is deposited on substrate, for example a stainless steel watch dial, and subsequently treated with a laser, such that the portion(s) of the layer treated with the laser change colour according to the laser power. This produces multicoloured surfaces having high resistance to corrosion and abrasion. The layer of LaBx is deposited by PVD and by cathode sputtering, using a LaB6 target of purple-violet colour, such that the colour of the deposited layer differs from the colour of the target. The laser treatment at specific powers changes the stoichiometry of the layer in the treatment portions, such that the colour of these portions changes according to the stoichiometry obtained. At higher powers, the laser will remove the layer of LaBx. Thus the colour of the treated portions is determined by the material of the substrate.