Wire Grid Polarizing Plate Protrusion Shape Optimization

Solution Overview

Problem

Current polarizing plates for liquid crystal projectors face challenges in achieving high transmittance while maintaining excellent heat resistance and light resistance, especially with the increasing brightness and intense light environments due to advancements in light sources from lamps to LEDs and lasers.

Innovation Solution

A polarizing plate with a wire grid structure featuring a transparent substrate and protrusions with a base shape portion that narrows towards the tip, optimized in shape and material composition to enhance light transmittance, including a laminated structure with a phase difference compensation element and coated with protective and water-repellent films.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wire grid polarizing plate is used to achieve high heat resistance and light resistance, then the polarizing plate can withstand intense light environments, but the light transmittance in the transmission axis direction is reduced

Engineering Contradiction:

Improveheat resistance and light resistanceVSAvoidlight transmittance

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by creating protrusions with varying cross-sectional shapes (triangular, trapezoidal, or rectangular) at specific locations on the wire grid. By optimizing the shape parameters (a/b ratio) of these localized protrusion structures, the patent achieves differential optical effects: the protrusions absorb polarized light in the transmission axis direction while maintaining high transmittance for the orthogonal polarization direction, thus resolving the contradiction between heat resistance and light transmittance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by systematically varying the cross-sectional shape parameters of the protrusions, specifically the ratio a/b where a is the height and b is the base width. By adjusting this parameter within specific ranges (0.5 < a/b ≤ 1.3), the patent optimizes the balance between light absorption for heat management and light transmission for brightness, enabling the polarizing plate to maintain both high heat resistance and high light transmittance

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If the grid structure is optimized to increase light transmittance, then the transmittance in the transmission axis direction improves, but the ability to tolerate intense light environments may be compromised

Engineering Contradiction:

Improvelight transmittanceVSAvoidtolerance to intense light

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating protrusions with varying cross-sectional shapes (triangular, trapezoidal, or rectangular) at specific locations on the wire grid. By optimizing the shape parameters (a/b ratio) of these localized protrusion structures, the patent achieves differential optical effects: the protrusions absorb polarized light in the transmission axis direction while maintaining high transmittance for the orthogonal polarization direction, thus resolving the contradiction between heat resistance and light transmittance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining the wire grid structure with protrusions made from different materials (metal, alloy, or semiconductor) having distinct optical properties. This composite structure enables the polarizing plate to simultaneously achieve high light transmittance through the optimized geometric parameters and high tolerance to intense light through the selective absorption properties of the protrusion materials

Inventive Principle:

Principle #40Composite materials

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 optimized polarizing plate achieves improved light transmittance characteristics in the transmission axis direction, providing superior heat resistance and high transmittance even in intense light environments, suitable for high-brightness applications like liquid crystal projectors.

Implementation Method 1

a protruding portion which protrudes from the base shape portion and absorbs light having a wavelength in the use band

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

When light is incident upon this polarizing plate, light that is polarized parallel to the direction of extension of the wires (TE waves (S-waves)) cannot pass through the polarizing plate, whereas light that is polarized in a direction perpendicular to the direction of extension of the wires (TM waves (P-waves)) can pass through the polarizing plate

Methodology Applied

Scientific EffectLight polarization: Polarisation

Data Source

PatentUS11543573B2Polarizing plate and optical apparatus containing same

Publication Date: 2023.01.03 DEXERIALS CORP

AI summary

A polarizing plate has a wire grid structure, and includes a transparent substrate, and a plurality of protrusions, which extend in a first direction (y-direction) on the transparent substrate and are periodically spaced apart from each other at a pitch that is shorter than a wavelength of a light in a use band, wherein each of the protrusions has a base shape portion which is formed having a width across the cross-section orthogonal to the first direction (y-direction) that narrows toward the tip, and a protruding portion which protrudes from the base shape portion and absorbs light having a wavelength in the use band.