Sub-mm Flat Lens Laser Separation on Glass and Quartz
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Solution Overview
Problem
Existing methods for fabricating small-sized optical lenses, particularly sub-mm flat lenses on glass or quartz substrates, face challenges such as birefringence issues with polymer-based lenses, difficulties in precise manufacturing, and incompatibility with semiconductor nanofabrication processes.
Innovation Solution
A method involving the formation of a flat lens structure on a substrate, deposition of a protective metal layer, laser irradiation to create a channel through the metal layer and substrate, and subsequent removal of the metal layer to separate the lens from the substrate, while using semiconductor nanofabrication techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical dicing is used to separate sub-mm flat lenses from glass substrate, then the lens can be separated, but the surface becomes contaminated with particles and scratches
Solution Approach 1:
The patent replaces mechanical dicing with laser dicing to separate sub-mm flat lenses from glass substrate. The laser beam ablates the substrate material without physical contact, eliminating mechanical scratches and particle contamination while achieving clean separation of the lens from the substrate.
Solution Approach 2:
The patent changes the separation method from mechanical to optical by using laser parameters (wavelength, power, pulse duration) to control the ablation process. This parameter change enables precise control of the separation depth and minimizes surface damage while maintaining manufacturing feasibility.
2Object-affected harmful factors
If plasma etching is used to minimize particle contamination during dicing, then particle contamination is reduced, but the process is incompatible with glass or quartz substrates
Solution Approach 1:
The patent replaces plasma etching with laser dicing, substituting a chemical process with an optical one. The laser method is universally applicable to glass and quartz substrates without the material-specific constraints of plasma etching, while simultaneously achieving low particle contamination through contactless processing.
Solution Approach 2:
The laser dicing method provides universal applicability across different substrate materials (glass, quartz, semiconductors) unlike plasma etching which is material-specific. This single method achieves both low particle contamination and broad substrate compatibility.
3Object-affected harmful factors
If mechanical grinding and polishing are used to fabricate glass based lenses, then optical quality is achieved, but precise alignment and manipulation of sub-mm lenses becomes difficult
Solution Approach 1:
The patent replaces mechanical grinding and polishing with laser dicing and semiconductor nanofabrication techniques. The laser method provides precise control over lens geometry and position directly during fabrication, eliminating the need for subsequent mechanical alignment operations and achieving sub-mm precision.
Solution Approach 2:
The patent changes the fabrication approach from mechanical removal of material to precise laser ablation and semiconductor processes. This enables direct writing of lens patterns with high precision, controlling lens position and dimensions without mechanical manipulation, thereby achieving both optical quality and alignment precision.
4Ease of manufacture
If polymer material is used for lens fabrication, then manufacturing is easier, but birefringence issues arise
Solution Approach 1:
The patent uses composite material approaches by combining glass substrate with deposited optical layers (such as silicon nitride, titanium dioxide) to create flat lenses. This composite structure enables precise control of optical properties without birefringence while maintaining ease of manufacture through semiconductor processing techniques.
Solution Approach 2:
The patent changes the material parameter from polymer to inorganic glass and deposited films. This material substitution eliminates birefringence while maintaining manufacturing ease through the use of standard semiconductor nanofabrication processes that can precisely control lens geometry and optical properties.
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 enables precise control over lens parameters, facilitates mass production of small flat lenses, and ensures compatibility with semiconductor processes, addressing the limitations of traditional methods.
Implementation Method 1
The protective layer helps to dissipate heat generated during laser dicing
Implementation Method 2
irradiating the protective metal layer with a laser to form a channel (i) through the protective metal layer
Implementation Method 3
The protective layer can be easily removed after laser dicing by a chemical solution
Data Source
AI summary
A method of fabricating an optical lens disclosed herein includes forming a layer of a flat lens structure on a front surface of a substrate, depositing a protective metal layer on the layer of the flat lens structure and on a back surface of the substrate, wherein the protective layer includes chromium, gold, titanium, or nickel, wherein the back surface is located opposite to and away from the front surface having the layer of the flat lens structure, irradiating the protective metal layer at the front surface with a laser to form a channel (i) through the protective metal layer, (ii) through the layer of the flat lens structure and (iii) in the substrate, removing the protective metal layer at the front surface and the back surface of the substrate, and separating the layer of the flat lens structure from the substrate to obtain the optical lens, wherein the channel has a depth defined by a thickness of the substrate remaining at the channel after irradiating the protective metal layer at the front surface with the laser. The optical lens fabricated from the method is also disclosed herein.