Asymmetric Wire Grid Polarizing Plate for Heat Resistance

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Solution Overview

Problem

Polarizing plates used in liquid crystal projectors face challenges in maintaining durability and optical properties under high-intensity light sources, as coatings to enhance durability can degrade optical performance.

Innovation Solution

A polarizing plate with a wire grid structure featuring a transparent substrate, projections, and a protective layer with specific absorption and reflective layers, along with dielectric layers, where the reflective layer's surface widths are asymmetrical and a base layer with pedestals, optimized for etching conditions to maintain optical clarity and heat resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protective film is coated on the wire grid structure to increase durability, then heat resistance is improved, but optical properties deteriorate

Engineering Contradiction:

Improveheat resistanceVSAvoidoptical properties

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protective layer is designed with spatially varying thickness, being thinner at the top surface and progressively thicker toward the bottom. This local variation allows the top surface to maintain excellent optical properties with minimal interference, while the bottom portion provides sufficient protection against thermal oxidation and mechanical damage. The asymmetric thickness profile resolves the contradiction by localizing protective functions where needed without compromising optical performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The protective layer's thickness is varied in the vertical dimension (depth direction) rather than uniformly across the surface. By creating a gradient in the thickness dimension from top to bottom, the design achieves both thin-profile optical clarity at the top and thick-profile protection at the bottom, effectively using dimensional variation to resolve the contradiction between optical properties and durability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If sidebars are widened to improve durability of wire grid polarizer, then structural stability is improved, but polarization characteristics degrade

Engineering Contradiction:

ImprovedurabilityVSAvoidpolarization characteristics

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protective layer applies local quality by providing enhanced protection at specific locations (the bottom portion and side regions) while maintaining minimal interference in the optical path (top surface). This localized approach allows durability improvement without compromising the polarization characteristics that depend on precise wire grid geometry at the top surface.

Inventive Principle:

Principle #3Local quality

3Strength

If overcoat layer is formed from tip to side wall to support wire grid polarizer, then structural support is improved, but number of air interfaces increases

Engineering Contradiction:

Improvestructural supportVSAvoidtransmittance

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The protective layer provides structural support locally at the bottom and side portions where the wire grid structure is most vulnerable to collapse, while maintaining transparency in the top region where light transmission occurs. This localized support approach reduces the number of air interfaces in the optical path compared to a uniform overcoat, thereby minimizing transmittance degradation while still providing necessary structural support.

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 provides enhanced heat resistance and optical properties, preventing thermal oxidation of the reflective layer while maintaining high transmittance and reflectance characteristics.

Implementation Method 1

a first absorption layer, a reflective layer, and a second absorption layer in order from a side close to the transparent substrate

Methodology Applied

Scientific EffectAbsorption of polarized light: Absorption (EM radiation)

Implementation Method 2

a reflective layer... a width of a first surface of the reflective layer on a side close to the transparent substrate in the first direction is wider than a width of a second surface of the reflective layer opposite to the first surface in the first direction

Methodology Applied

Scientific EffectReflection of polarized light: Reflection

Data Source

PatentUS20250004178A1Polarizing plate, optical equipment, and method for manufacturing a polarizing plate

Publication Date: 2025.01.02 DEXERIALS CORP

AI summary

A polarizing plate having a wire grid structure includes: a transparent substrate; a plurality of projections disposed on the transparent substrate and spaced apart from each other and periodically arranged in a first direction at a pitch shorter than a bandwidth to be used; and a protective layer that covers the projections and the transparent substrate, wherein each of the projections has a first absorption layer, a reflective layer, and a second absorption layer in order from a side close to the transparent substrate, and a width of a first surface of the reflective layer on a side close to the transparent substrate in the first direction is wider than a width of a second surface of the reflective layer opposite to the first surface in the first direction.