Wire Grid Polarizer Resonance Shift High Transmittance

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Solution Overview

Problem

Existing wire grid polarizers fail to achieve a sufficient degree of polarization in the short-wavelength region of visible light and struggle to maintain high transmittance across a wide visible spectrum, particularly when used as diffraction gratings.

Innovation Solution

A wire grid polarizer is designed with a resin substrate having grid-shaped convex portions, a dielectric layer with a higher refractive index than the resin substrate, and metal wires deposited at an angle, allowing for efficient polarization and transmittance across the visible spectrum, with pitches of the grid-shaped convex portions set at 120 nm or less.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a wire grid polarizer uses a conventional structure with conductive elements on convex portions of a glass substrate, then it can achieve polarization function, but it fails to obtain a sufficient degree of polarization in the short-wavelength region of visible light

Engineering Contradiction:
Improvedegree of polarizationVSAvoidtransmittance in short-wavelength region
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent changes the refractive index parameter by introducing a dielectric layer with higher refractive index than the resin substrate. This parameter change shifts the resonance point to shorter wavelengths, enabling sufficient polarization degree in the short-wavelength region while maintaining high transmittance across the visible spectrum

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure combining resin substrate, dielectric layer with higher refractive index, and metal wires. This composite material approach allows optimization of optical properties for both polarization degree and transmittance in the visible region, particularly in the short-wavelength range

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If a wire grid polarizer is designed to achieve high degree of polarization in short-wavelength region, then polarization performance improves, but transmittance across the wide visible spectrum deteriorates

Engineering Contradiction:
Improvedegree of polarizationVSAvoidlight transmittance
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

By adjusting the refractive index parameter through the dielectric layer and optimizing the pitch of grid-shaped convex portions to 120 nm or less, the patent achieves resonance characteristics that simultaneously provide high polarization degree and high transmittance across the entire visible spectrum

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different materials with specific properties to different regions: the dielectric layer with higher refractive index is positioned where it can most effectively shift the resonance point, while the metal wires are arranged with specific pitch to achieve both polarization and transmittance optimization in their respective functional zones

Inventive Principle:
Principle #3Local quality

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 a high degree of polarization (99.9% or more) and excellent transmittance over the entire visible region, enabling effective use in large-area applications such as liquid crystal display devices.

Implementation Method 1

it is possible to shift to a short-wavelength region a resonance point of causing a resonance phenomenon such that transmission and reflection characteristics of the light rapidly change

Methodology Applied
Scientific EffectResonance: Resonance

Implementation Method 2

the wire grid reflects almost all the electric field vector component of the light vibrating in parallel with the wires, while allowing almost all the electric field vector component of the light perpendicular to the wires to pass through the grid

Methodology Applied
Scientific EffectPolarization: Polarisation

Implementation Method 3

The wire grid polarizer reflects the light which is not passed through to be reused

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2090909B1Wire grid polarizer and manufacturing method of the same
Publication Date: 2012.08.29 ASAHI KASEI E-MATERIALS CORPORATION
  • EP2090909B1 patent drawingFigure 1
  • EP2090909B1 patent drawingFigure 2(a)~2(c)
  • EP2090909B1 patent drawingFigure 3(a)~3(b)

AI summary

There is disclosed herein a wire grid polarizer (12) comprising: a resin substrate (1) having grid-shaped convex portions (1a); a dielectric layer (2) provided to cover the grid-shaped convex portions (1a) of the resin substrate (1) and at least part of the side faces of the portions (1a); and metal wires (3) provided on the dielectric layer (2).