Micro-Lens Fabrication via Molten Surface Tension
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Solution Overview
Problem
Existing methods for fabricating lenses and lens arrays at micro- or nano-scales face challenges such as low yield, high cost, shape distortions, surface roughness, and limitations in achieving small dimensions, leading to suboptimal optical performance and increased costs.
Innovation Solution
A method utilizing the surface tension of a molten lens material to define the curved shape of lenses and lens arrays, allowing for precise fabrication of various types and sizes, including dimensions as small as a few nanometers, with unprecedented surface smoothness and low manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional fabrication methods (photolithography, RIE, FIB) are used to make micro-lenses, then lenses can be fabricated at small dimensions, but the surface smoothness is very rough (more than a few nanometers) which degrades optical performance due to photon scattering
Solution Approach 1:
The patent utilizes the phase transition of lens material from solid to liquid state through heating above its melting point, allowing the material to be reshaped by surface tension into a smooth curved lens profile, then solidifies upon cooling to retain the precise shape with superior surface smoothness
Solution Approach 2:
The patent changes the physical state parameter of the lens material from solid to liquid by controlling temperature above the melting point, enabling the material to flow and form smooth surfaces dictated by surface tension, then reverses the parameter change by cooling to solidify the final lens shape
2Ease of manufacture
If molding and embossing are used to fabricate lenses, then the high cost of the tool mold can be amortized over many parts to obtain relatively low cost, but the process uses elevated temperature which causes large thermal expansion coefficients and results in lens shapes that distort as the lens material cools
Solution Approach 1:
The patent employs phase transition of the lens material from solid to liquid and back to solid, where the material is heated above its melting point to become moldable, shaped by surface tension, then cooled to solidify into the final lens shape, avoiding the thermal expansion distortion problems of conventional molding
Solution Approach 2:
The patent utilizes surface tension as a self-organizing force that automatically forms the optimal curved lens profile without requiring complex external molds or tooling, allowing the material to self-shape into the desired lens geometry based on its own surface energy minimization
3Manufacturing precision
If FIB tool is used to make lenses, then precise lens shapes can be achieved, but the process is extremely slow and performed on very expensive equipment, making it extremely expensive to produce lenses
Solution Approach 1:
The patent replaces the mechanical FIB machining process with a thermal-phase transition process where heating and surface tension naturally form the lens shape, eliminating the need for slow, sequential material removal and enabling parallel processing of multiple lenses
4Length of stationary object
If conventional methods are used to fabricate extremely small-dimensioned lenses, then the lower limit of dimensions can be approached, but the distortions on the shape of the lenses, surface roughness, and other quality aspects increasingly and quickly degrade
Solution Approach 1:
The patent uses phase transition to melt and reshape material at the micro and nanoscale, where surface tension dominates over gravity and other forces, enabling precise formation of small-dimensioned lenses with smooth surfaces and accurate shapes that conventional mechanical methods cannot achieve
Solution Approach 2:
The patent employs surface tension as a self-organizing force that automatically forms the optimal lens profile without requiring external molds or tooling, allowing the material to self-shape into the desired lens geometry based on its own surface energy minimization, which is particularly effective at small dimensions
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 the production of high-quality lenses and lens arrays with superior optical properties and smooth surfaces, achieving precise shapes and low costs, particularly suitable for extreme wavelengths like UV and X-ray applications.
Implementation Method 1
using the surface tension of the lens material in a molten state to allow the curved shape of the lens to be precisely defined
Implementation Method 2
the lens material in a molten state
Data Source
AI summary
A method is disclosed of implementing lens elements or lens arrays having dimensions ranging from a few centimeters down to the micro-scale or nano-scale using the surface tension of the lens material in a molten state to allow the curved shape of the lens to be precisely defined. The method has useful application in the fabrication of lens elements and lens arrays out of a large variety of material types, including elemental materials, as well as compound materials and alloys. The method also allows the implementation of lenses having far superior surface smoothness compared to other approaches, as well as very accurate lens shapes. The method allows the making of high quality lenses and lens arrays, wherein the diameter of the lenses are on the order of a few microns or less. Convex, concave, plano-convex, plano-concave, compound lenses, and many other types of lens shapes can be implemented using the method of the present invention.