One-Sided Photochromic Lens Dyeing via Selective Etching
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Solution Overview
Problem
Existing methods for applying functional and non-functional tinting to spectacle lenses are complex and costly, requiring specialized equipment, limiting mass production and flexibility in application.
Innovation Solution
A method for applying non-functional dye to both sides of a substrate, followed by applying a photochromic dye to one side and then removing the dye from the other side, using conventional dyeing systems and simple post-processing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a vapor deposition device with a dedicated dye application surface is used to apply non-functional dye, then the tint can be applied to one side of the lens, but the equipment complexity increases and production cost rises
Solution Approach 1:
The process is divided into separate stages: first applying non-functional dye to both sides of the lens using a conventional dye bath, then applying functional photochromic dye to the convex side using spin coating, and finally removing the non-functional dye from the concave side through selective etching. This segmentation allows each step to use appropriate, simpler equipment rather than requiring a complex integrated vapor deposition device.
Solution Approach 2:
The non-functional dye is applied to both sides of the lens in advance using a conventional dye bath before the functional photochromic dye is applied. This preliminary action allows the use of simple, existing dyeing equipment rather than requiring specialized vapor deposition equipment, and the subsequent selective removal of dye from one side achieves the desired one-sided tinted appearance.
2Ease of manufacture
If non-functional dye must be sublimable for vapor deposition, then one-sided tinting can be achieved, but the selection of available dyes is limited
Solution Approach 1:
The invention changes the application method parameter from vapor deposition to liquid-phase dyeing followed by selective removal. This allows the use of any conventional non-functional dye that can be dissolved in a dye bath, eliminating the restriction to only sublimable dyes and expanding the variety of available color options for the tint.
3Device complexity
If both tinting steps are applied to the convex surface, then equipment can be simplified, but controlling the functional tint effect becomes difficult due to UV light intensity differences
Solution Approach 1:
The invention applies the non-functional dye to both sides of the lens asymmetrically, then selectively removes it from the concave side. The functional photochromic dye is applied only to the convex side. This asymmetric treatment ensures the functional tint is applied to the correct surface for optimal UV light interaction while maintaining equipment simplicity.
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
Enables cost-effective, one-sided application of color and functional tinting, facilitating mass production and reducing equipment requirements.
Implementation Method 1
a photochromic dye, which undergoes a reversible change in its molecular structure, and thus its absorption properties, when exposed to UV light
Implementation Method 2
heating the substrate by a heating source under vacuum conditions in the vapor deposition device, whereby the non-functional dye of the dye application surface is sublimated and vapor deposition of the sublimated non-functional dye onto the convex main surface of the lens takes place
Data Source
Figure 1(a)~1(e)
AI summary
The invention relates to a method for providing a substrate with a colouring an a functional colouring on one side, comprising the following steps (a) to (d): providing a substrate to be provided with a colouring and a functional colouring on one side, wherein the substrate is a semi-finished part produced from plastic glass and having a first main side and a second main side opposite the first main side and with a convex shape; (b) applying a colouring to both main sides of the substrate provided in step (a); (c) applying a functional colouring to the second main side of the substrate provided with a colouring on both main sides in step (b), wherein the functional colouring is generated by at least one photochromic colouring agent and the at least one photochromic colouring agent is contained in a photoresist forming a polymer layer on the substrate; and (d) post-processing the substrate provided with a functional colouring on the second main side in step (c), in such a way that the colouring on the first main side is removed, thereby producing a substrate provided with a colouring and a functional colouring only on the second main side.