Diffractive Optical Element High-Aspect-Ratio Resin Molding
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Solution Overview
Problem
The production of diffractive optical elements for infrared light is hindered by the complexity and cost of electron beam lithography, and molding techniques using ionizing radiation curable resins face issues with demolding and fracture, especially for high-aspect-ratio features, which affects the uniformity and durability of the diffracted light.
Innovation Solution
A diffractive optical element with a diffractive layer having high refractive index portions with an aspect ratio of 2 or more, disposed on a transparent substrate, and an antireflection layer, using an ionizing radiation curable resin composition with specific storage modulus and loss modulus properties to prevent breakage and sticking, enabling the formation of convexities with heights of 1000 nm or more for infrared light diffractive applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electron beam lithography is used to produce diffractive optical elements for infrared light, then manufacturing precision is improved, but device complexity and production cost increase
Solution Approach 1:
The patent uses a mold with pre-formed diffractive patterns to copy and replicate the optical element structure through molding. This replaces the need for complex electron beam lithography in mass production, while maintaining manufacturing precision through the master mold that was initially created using precise lithography methods.
Solution Approach 2:
The patent changes the production method from direct lithography to molding replication. By using a mold that can be reused multiple times, the complexity and cost of production are reduced while maintaining the precision of the diffractive patterns through the master mold fabrication process.
2Manufacturing precision
If high-aspect-ratio convexities are formed in ionizing radiation curable resin, then diffractive performance for infrared light is improved, but demolding difficulty and fracture risk increase
Solution Approach 1:
The patent modifies the physical and chemical parameters of the resin composition, specifically controlling the storage modulus and loss modulus ratios. By adjusting these viscoelastic properties, the resin maintains shape fidelity for high-aspect-ratio convexities during curing while becoming sufficiently flexible during demolding to prevent fracture.
Solution Approach 2:
The patent uses a composite resin system comprising multiple components including polyfunctional acrylates, monofunctional acrylates, and photopolymerization initiators. This composite formulation achieves the desired balance between structural integrity for pattern formation and flexibility for demolding.
3Ease of manufacture
If conventional resin molding is used for high-aspect-ratio features, then production cost is reduced, but demolding and fracture issues arise
Solution Approach 1:
The patent changes the viscoelastic parameters of the resin by controlling the storage modulus to be 1×10^8 Pa or more and the loss modulus to be 1×10^7 Pa or more, with a specific ratio between them. This parameter optimization enables simple molding processes to produce high-aspect-ratio features that can be successfully demolded without fracture.
Solution Approach 2:
The patent employs a disposable moldable resin that can be easily formed and then discarded or reused after demolding. The resin's controlled viscoelastic properties allow for simple molding techniques using inexpensive molds, making the process economically viable despite the complexity of forming high-aspect-ratio features.
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 solution provides a durable diffractive optical element capable of shaping infrared light into a desired pattern with reduced zeroth-order light, enhancing the efficiency and reliability of light irradiation while simplifying the production process and reducing costs.
Implementation Method 1
a diffractive optical element (DOE) is provided, which utilizes a diffraction phenomenon that is observed when light passes through an area where materials with different refractive indices are periodically arranged
Implementation Method 2
forming a cured film from the ionizing radiation curable resin composition by irradiating the curable resin composition with ionizing radiation
Data Source
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AI summary
The present invention is to provide a diffractive optical element being configured to provide desired diffracted light and being excellent in durability. Disclosed is a diffractive optical element for shaping light from a light source, wherein the diffractive optical element is provided with a diffractive layer having a periodic structure comprising low refractive index portions and high refractive index portions, and the high refractive index portions of the periodic structure include one having an aspect ratio of 2 or more.