Optical Element Laser Ablation for Precise 3D Surface Processing
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Solution Overview
Problem
Current methods for producing transmissive and reflective optics are complex, require extensive measurement technology, and are not cost-effective, especially when dealing with 3D shaped surfaces and temperature-sensitive materials.
Innovation Solution
A method using ultra-short pulse duration ablation lasers that directly evaporate material without significant interaction, allowing for precise processing with minimal damage, and enabling the use of various materials like plastics, glass, and ceramics, with optional density gradients and multi-material blanks for adjustable refractive behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional laser processing methods are used on 3D shaped surfaces, then material removal can be achieved, but the process requires complex measurement technology and multiple iterative steps, increasing device complexity and production time
Solution Approach 1:
The patent replaces complex mechanical measurement and iterative processing systems with ultrashort pulse laser ablation. The laser directly removes material with precise control through pulse duration and energy parameters, eliminating the need for complex measurement technology and multiple iterative steps while achieving high surface processing precision.
Solution Approach 2:
The patent employs periodic ultrashort laser pulses to remove material layer by layer. Each pulse creates controlled ablation, and by adjusting pulse duration and repetition rate, the process achieves precise material removal without requiring complex measurement systems or multiple iterative cycles.
2Adaptability or versatility
If ablation agents are used with laser radiation for material removal, then hard materials can be processed, but the laser does not act directly on the blank surface, requiring additional components and process complexity
Solution Approach 1:
The patent extracts and eliminates the ablation agent from the processing system. Instead of using separate ablation agents that require evaporators and additional supply mechanisms, the ultrashort pulse laser directly ablates the material surface through pure vaporization, simplifying the device while maintaining versatility for processing hard and temperature-sensitive materials.
Solution Approach 2:
The patent removes the intermediary ablation agent between the laser and the blank. The laser radiation acts directly on the material surface, with the ultrashort pulse duration enabling direct material interaction and removal without requiring intermediate substances, thereby reducing process complexity.
3Use of energy by moving object
If long pulse duration laser radiation is used for material removal, then higher energy can be delivered, but the evaporating material impedes energy input and causes thermal damage to the treated material
Solution Approach 1:
The patent uses ultrashort laser pulses with duration between 60-500 femtoseconds, delivering high peak energy in extremely short intervals. This periodic action allows the material to vaporize and escape between pulses, preventing energy impediment and thermal damage while maintaining high energy delivery efficiency.
Solution Approach 2:
The patent employs ultrashort pulses that rush through the material interaction process so quickly that the evaporating material does not have time to impede subsequent energy input. The extremely short pulse duration enables the laser to deliver high energy and complete the ablation process before thermal diffusion can cause damage to surrounding material.
4Manufacturing precision
If iterative coarse removal and polishing processes are used for optical element manufacturing, then surface precision can be achieved, but the process requires multiple steps and complex measurement technology, reducing productivity
Solution Approach 1:
The patent replaces iterative mechanical coarse removal and polishing processes with direct ultrashort pulse laser ablation. The laser precisely removes material in controlled amounts through adjusted pulse parameters, achieving optical surface precision in fewer steps and significantly increasing production speed without requiring complex measurement and iterative processing.
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 rapid, cost-effective production of optics with precise surface processing and reduced curvature, allowing for flexible lens designs that can be rolled or folded for easier insertion, and minimizes material damage and reflections through controlled energy distribution and density gradients.
Implementation Method 1
A method is presented for producing a transmissive or reflective optic from a blank using a laser. The laser is an ablation laser with a pulse duration of between 60 and 500 femtoseconds. The laser radiation removes material from the blank in a pulse-wise manner with the blank rotating relative to the laser.
Implementation Method 2
Material removal is achieved through direct evaporation, thus causing minimal damage to the treated material. The extremely short pulse duration of the ablation laser means that the material evaporating during the pulse does not impede the energy input after evaporation.
Data Source
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AI summary
In a method for producing a transmissive or reflective optical element from a blank, material is removed from the blank by means of a material removal laser and the pulse duration of the material removal laser is less than 1 ns and is preferably between 3 fs and 100 fs or between 100 fs and 10 ps.