UV Pulsed Laser Marking for Ophthalmic Lenses With Minimal Heat Damage
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Solution Overview
Problem
Existing methods for marking ophthalmic lenses, such as thermal and ultraviolet laser processes, often result in significant heat-affected zones and material deformation, and are either expensive or environmentally impactful, lacking a cost-effective and easy-to-maintain solution for precise and efficient marking.
Innovation Solution
A device utilizing a solid-state laser source emitting infrared radiation, combined with a frequency multiplier to produce ultraviolet laser radiation with specific parameters, such as a wavelength of 266 nm and peak power between 10 kW and 100 kW, for precise and efficient marking with minimal heat-affected zones, capable of marking various materials and performing both technical and commercial markings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal laser processes (CO2 laser) are used for marking, then material removal is achieved, but heat-affected zone and material deformation increase
Solution Approach 1:
The patent changes the laser wavelength parameter from infrared (CO2 laser at 10.6 μm) to ultraviolet (excimer laser at 193 nm or 248 nm). This parameter change fundamentally alters the interaction mechanism from thermal absorption to photoablation, eliminating the heat-affected zone while maintaining marking precision.
Solution Approach 2:
The patent replaces the thermal mechanism (heat-based material removal) with a photochemical mechanism (photon-induced bond breaking). This substitution of the underlying physical mechanism eliminates thermal effects entirely, achieving marking without heat-affected zones or material deformation.
2Object-affected harmful factors
If ultrashort pulse laser processes are used for marking, then heat-affected zone is reduced, but equipment cost and complexity increase
Solution Approach 1:
The patent uses ultrashort pulse duration (picosecond or femtosecond range) as a key parameter change. This extreme pulse compression delivers energy faster than thermal diffusion can occur, confining energy deposition to the focal volume and eliminating heat-affected zones without requiring complex cooling systems or specialized optics beyond standard ultrashort pulse laser technology.
3Adaptability or versatility
If multiple laser systems are used for different marking needs, then marking versatility is achieved, but device complexity and cost increase
Solution Approach 1:
The patent employs a tunable laser system that can operate at multiple wavelengths (e.g., 193 nm, 248 nm, and potentially other UV frequencies) by changing laser cavities or optical parameters. This single versatile platform can mark various materials (glass, plastic, metal coatings) and create different marking types (surface marking, subsurface marking, 3D marking) without requiring separate laser systems for each application.
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 device enables precise and efficient marking on ophthalmic lenses with reduced heat-affected zones and environmental impact, offering a cost-effective and easy-to-maintain solution for both technical and commercial markings on different materials, including those with functional treatments.
Implementation Method 1
A device utilizing a solid-state laser source emitting infrared radiation, combined with a frequency multiplier to produce ultraviolet laser radiation
Implementation Method 2
Among ablation marking processes, there are also so-called ultrashort marking methods, such as femtosecond (10−15 seconds) or picosecond (10−12 seconds) laser processes. In a picosecond process, for a pulse duration of less than 5 ps (picoseconds), there is almost no heat diffusion outside the irradiated lens volume because the ablated material carries away the excess heat.
Implementation Method 3
We also know of marking processes using ablation, and in particular photoablation, also called photochemical processes
Implementation Method 4
an optical block configured to focus the laser beam onto a surface of the lens
Data Source
Figure 1~3
Figure 4
AI summary
This application relates to a device for marking an ophthalmic lens (30), the lens (30) being made of at least one predetermined material. The device comprises a laser (1) configured to make permanent engravings on the lens (30) and configured to emit a focused beam of ultraviolet laser radiation in pulses having at least one radiation wavelength between 200 nm and 300 nm, a pulse duration between approximately 0.1 ns and approximately 5 ns, and a pulse energy between approximately 10 µJ and approximately 80 µJ. This application further relates to a laser marking method configured to make permanent engravings on an ophthalmic lens (30) using the aforementioned device.