Silicon UV Polarization Element Thermal Stability
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Solution Overview
Problem
Existing polarization separation elements, particularly those using aluminum, face limitations in polarizing light in the ultraviolet ray region due to pitch dependency and lack of thermal stability, leading to reduced polarization efficiency and durability.
Innovation Solution
A polarization separation element featuring a substrate with silicon-based convex portions and dielectric concave portions, optimized for ultraviolet ray polarization, with specific refractive indices and extinction coefficients, allowing for lower pitch dependency and enhanced thermal stability, thereby achieving superior polarization performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum is used as the polarization separation element material, then the manufacturing process is simple, but the thermal stability and polarization efficiency in ultraviolet region are poor
Solution Approach 1:
The patent changes the material parameter from aluminum to silicon, which has a higher oxidation temperature (about 800°C), thereby improving thermal stability and polarization efficiency in the ultraviolet region while maintaining manufacturing feasibility through established semiconductor fabrication processes
Solution Approach 2:
The patent uses a composite structure combining silicon convex portions with a dielectric material concave portions, creating a composite polarization separation element that leverages the high-temperature stability of silicon and the optical properties of dielectric materials to achieve superior performance
2Reliability
If the pitch of convex portions is reduced to improve polarization at short wavelengths, then polarization efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the pitch parameter to specific ranges (50-150 nm, preferably 110-150 nm) where silicon's optical properties (refractive index 1-10, extinction coefficient 0.5-10) provide sufficient polarization efficiency, balancing performance with manufacturability using standard lithography techniques
3Duration of action of stationary object
If aluminum is used for polarization separation, then the structure is simple, but oxidation occurs under heat leading to reduced durability
Solution Approach 1:
The patent changes the material's oxidation resistance parameter by selecting silicon, which has a much higher oxidation temperature (about 800°C) compared to aluminum, thereby preventing oxidation under ultraviolet light heat and maintaining long-term durability and polarization performance
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 achieves high polarization degrees and extinction ratios even at short wavelengths, maintaining performance and durability in the ultraviolet ray region, with a simpler manufacturing process and reduced risk of oxidation.
Implementation Method 1
The silicon has a light absorption characteristic unlike aluminum which is a reflecting material. Therefore, if the silicon is used as a material of the convex portion 2a, it is possible to polarize light in an ultraviolet ray region
Implementation Method 2
an unevenness formed on the substrate and generates linearly polarized light having a wavelength in an ultraviolet ray region
Data Source
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AI summary
Provided are a polarization separation element, a method for manufacturing the polarization separation element, a light irradiating device, a method for irradiating light, and a method for manufacturing a photo-alignment film. An ultraviolet ray polarization separation element according to the present application has superior durability to ultraviolet rays and heat, and involves a simple manufacturing process due to a low pitch dependency of polarizing characteristics. Further, the polarization separation element according to the present application can achieve superior polarization degree and extinction ratio even within a short wavelength region.