Curved Mask Patterning for Defect-Free Optical Lenses
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for manufacturing corrective spectacle lenses with surface microstructures are costly and limited in microstructure variety, and glass inserts are difficult to work with due to poor thermal conductivity, making it challenging to produce defect-free lenses with precise microstructures.
Innovation Solution
A method involving a patterned mask with a curved surface, made by illuminating selected micrometer-sized areas to create local variations in optical properties, allowing for precise etching of microstructures on materials like photoresist or high-energy beam sensitive glass, which can be used to create molds for lenses with uniform microstructures normal to the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If steel inserts are used for injection molding, then microstructures can be produced, but manufacturing cost is very high
Solution Approach 1:
The patent replaces expensive steel inserts with disposable glass inserts that can be used for injection molding. The glass inserts are patterned with microstructures through a lithography process, allowing precise microstructure production at lower cost. After use, the glass inserts can be discarded or reused limited times, significantly reducing manufacturing cost compared to steel inserts while maintaining microstructure production capability.
2Manufacturing precision
If glass inserts are used for injection molding, then thermal conductivity is improved, but producing precise microstructures on glass surface is difficult
Solution Approach 1:
The patent applies preliminary patterning actions to the glass insert surface before injection molding. A photoresist layer is deposited on the glass insert, then illuminated through a photomask to create a latent image of the desired microstructures. This preliminary patterning step enables precise microstructure formation on the glass surface, overcoming the difficulty of directly forming microstructures on glass.
Solution Approach 2:
The patent introduces a photoresist layer as an intermediary between the glass insert and the final microstructure. The photoresist receives the illumination pattern, undergoes chemical changes, and is then developed to reveal the microstructure pattern on the glass surface. This intermediary material facilitates the transfer of precise microstructures from the photomask to the glass insert, solving the problem of difficult direct microstructure formation on glass.
3Adaptability or versatility
If diamond turning is used to create microstructures, then microstructures can be produced, but only limited types of microstructures can be generated
Solution Approach 1:
The patent replaces the mechanical diamond turning process with a photolithography-based chemical process. Instead of mechanically cutting microstructures with a diamond tool, the patent uses light illumination through a photomask to create a pattern on photoresist, followed by chemical development and etching. This substitution enables versatile microstructure types including complex geometries, varying depths, and intricate patterns that cannot be achieved through mechanical diamond turning.
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 weld-line free, defect-free optical lenses with surface microstructures that slow down myopia progression, using materials with thermal conductivity similar to borosilicate glass, allowing for efficient injection molding and casting of lenses with precise microstructures.
Implementation Method 1
the curved surface is made of a material which, when thusly illuminated, undergoes local transformations over the illuminated areas, the local transformations being related to the local variations of the optical property
Implementation Method 2
the patterned curved mask to significantly diffract visible light. This allows the patterned curved mask to be used as a grayscale curved mask for visible light by taking advantage of wave interference phenomena
Data Source
Figure 1(a)~1(f)
Figure 2(a)~2(d)
Figure 3~4
AI summary
The disclosure relates to a method for preparing an object having a curved surface to be etched, the resulting etched surface being useable as a mold for manufacturing an optical article. The method comprises illuminating the curved surface of the object through a patterned mask placed over or on the curved surface. The patterned mask comprises a curved surface that is configured to conform to the curved surface of the object. The curved surface of the patterned mask comprises at least one micrometer-sized area that differs in transmission function from an adjacent area. The curved surface is made of a material which, when thusly illuminated, undergoes local changes in a chemical resistance to a developer. The disclosure further relates to a method for patterning a mask having a curved surface and to an optical article having a curved surface comprising microstructures that are uniformly normal to the curved surface.