Wire Grid Polarizer Structure for UV Contrast and Durability
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Solution Overview
Problem
Existing wire grid polarizers face challenges in achieving high contrast between transmitted and absorbed polarization states, particularly in the ultraviolet spectrum, and require improved durability against environmental factors like heat, moisture, and ultraviolet light.
Innovation Solution
The development of wire grid polarizers with silicon cores and silicon dioxide ribs, where the core is sandwiched between a pair of ribs, and optionally capped with a low-index material, enhances transmission of the desired polarization while minimizing absorption, and is manufactured through precise deposition and etching processes to ensure structural integrity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wire grid polarizer structures are used, then manufacturing is simpler, but contrast ratio and durability in ultraviolet spectrum are insufficient
Solution Approach 1:
The patent employs composite material structures where a silicon core is combined with silicon dioxide ribs and capped with low-index materials. This composite approach enhances the polarizer's durability and UV performance while maintaining structural integrity through the synergistic combination of materials with complementary properties.
Solution Approach 2:
The invention applies local quality by creating regions with different material properties within the wire structure. The silicon core provides mechanical strength and UV stability, the silicon dioxide ribs provide structural support and optical control, and the low-index cap material optimizes optical performance. Each region is specifically engineered for its local function to collectively improve overall reliability.
2Reliability
If high contrast is achieved by increasing transmission of predominantly-transmitted polarization, then contrast ratio improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes contrast ratio by carefully controlling key parameters including wire pitch, wire width, rib dimensions, and material refractive indices. By systematically adjusting these parameters during design and manufacturing, high contrast ratios are achieved while maintaining feasible manufacturing precision requirements through established fabrication processes.
3Object-affected harmful factors
If durability against environmental factors is improved through material selection, then resistance to heat and moisture increases, but manufacturing complexity increases
Solution Approach 1:
The patent uses composite materials specifically selected for their environmental resistance properties. Silicon provides excellent thermal stability and UV resistance, silicon dioxide offers moisture barrier properties and chemical inertness, and the low-index cap materials are chosen for their environmental stability. This composite structure collectively resists heat, moisture, and UV degradation while using materials compatible with standard semiconductor fabrication processes.
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 proposed design achieves high performance across a broad range of ultraviolet spectrum and angles of incidence, with improved durability and resistance to environmental stressors, thereby enhancing the contrast ratio and longevity of the polarizer.
Implementation Method 1
A wire grid polarizer (WGP) can divide light into two different polarization states. One polarization state can primarily pass through the WGP and the other polarization state can be primarily absorbed or reflected.
Implementation Method 2
The distal end of the core can be capped with a material having a low index of refraction
Data Source
AI summary
The wire grid polarizers 10 and 30 described herein, and wire grid polarizers made by methods described herein, can have high performance across a broad range of the ultraviolet spectrum and across a broad angle of incidence. These polarizers can be durable (resistant to heat, moisture, ultraviolet light, and oxidation). The polarizer can include an array of wires 15 on a substrate 11. Each wire 15 can have a silicon core 12 and a pair of silicon dioxide ribs 13. The core 12 can be sandwiched between the pair of ribs 13, with each rib 13 adjacent to a sidewall 12s of the core 12. A rib width W13 can be ≥4 nm. Each wire 15 can also include a silicon dioxide cap 14. The core 12 can be encircled by a silicon dioxide ring 17.