Dyeing method and dyeing apparatus
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Solution Overview
Problem
Conventional methods for dyeing high refractive index plastic lenses, such as the vapor deposition transfer method, require increased heating temperatures and times, leading to yellow discoloration, while laser dyeing methods struggle to achieve desired color density due to sublimation of dyes.
Innovation Solution
A dyeing method using a laser beam with a wavelength that is less likely to be absorbed by the dye but absorbed by the transparent resin body, allowing for localized heating of the resin surface without melting, enabling efficient dye fixation and preventing dye sublimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the vapor deposition transfer dyeing method is used to dye high refractive index lenses, then the lens can be dyed, but the heating temperature and time must be increased, causing yellow discoloration of the lens
Solution Approach 1:
The patent applies local quality by using a laser beam to heat only the surface region of the lens where the dye is applied, rather than heating the entire lens. This localized heating approach allows the dye to be fixed and dispersed into the lens surface without subjecting the bulk lens material to high temperatures that would cause yellow discoloration. The laser energy is concentrated on the dye-containing surface layer, creating a temperature gradient that fixes the dye while preserving the optical clarity of the lens.
Solution Approach 2:
The patent changes the heating parameters from conventional high-temperature oven heating to controlled laser beam heating. By using a laser beam with specific wavelength and power density, the heating process is transformed from bulk thermal heating to surface-specific photothermal heating. This parameter change enables rapid heating of the dye layer to fixation temperature without maintaining the entire lens at temperatures that would cause yellow discoloration, thus resolving the contradiction between dye fixation quality and prevention of yellow discoloration.
2Productivity
If a laser beam is used to heat the dye for fixation, then the heating time is reduced, but the dye is heated and sublimed, preventing desired color density
Solution Approach 1:
The patent applies local quality by directing the laser beam to heat primarily the lens material and dye interface rather than heating the free dye particles on the surface. The laser energy penetrates through the dye layer and is absorbed by the lens material, which then conducts heat to the dye, fixing it through controlled thermal diffusion. This approach maintains the dye in place while achieving fixation, preventing sublimation loss even though the process is rapid.
Solution Approach 2:
The patent uses the lens material itself as an intermediary heat transfer medium. Instead of directly heating the dye particles with the laser beam (which would cause sublimation), the laser heats the lens material first, and the lens material then transfers heat to the dye through thermal conduction. This intermediary approach allows for rapid heating and fixation while keeping the dye particles stable and preventing their sublimation, thus maintaining color density.
3Manufacturing precision
If the entire lens is heated for dye fixation, then the dye is fixed uniformly, but the lens turns yellow due to chemical changes
Solution Approach 1:
The patent applies local quality by restricting the heating zone to only the surface region of the lens where the dye is applied. The laser beam creates a localized heated zone at the surface, sufficient for dye fixation and dispersion, while the bulk of the lens remains at ambient or low temperature. This spatial differentiation in temperature distribution achieves uniform dye fixation in the surface region without causing yellow discoloration in the lens material, as the bulk material is not subjected to temperatures that would trigger chemical changes.
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
This method allows for rapid dyeing of high refractive index plastic lenses without yellow discoloration, maintaining consistent color tone and density, as the dye is dispersed into the resin without heating the entire lens, thus preventing sublimation.
Implementation Method 1
irradiating a laser beam having a wavelength less likely to be absorbed by the dye toward the transparent resin body to heat the dye through the transparent resin body and heat the transparent resin body
Implementation Method 2
a wavelength less likely to be absorbed by the dye but is absorbed by the transparent resin body
Implementation Method 3
heat the transparent resin body to a temperature that does not melt the surface of the transparent resin body and that causes the heated dye to be dispersed into the transparent resin body
Data Source
AI summary
Disclosed is a dyeing method using a laser beam. The method can dye transparent resins such as plastic lens well. Also disclosed is a dyeing apparatus. The dyeing method comprises heating a plastic lens having a dye-coated surface to fix the dye on the surface of the plastic lens. The method comprises the step of applying a laser beam with a wavelength, which is less likely to be absorbed in the dye but it absorbed in the plastic lens, onto the surface of the plastic lens through the dye.