Wire Grid Polarizing Plate Reflective Layer Width Control

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Solution Overview

Problem

Inorganic polarizing plates face challenges in achieving accurate control over wavelength dispersion of absorption axis reflectance due to variations in etching processes, leading to inconsistent performance across different liquid crystal projector manufacturers.

Innovation Solution

A polarizing plate with a wire grid structure, featuring grid protrusions with a reflective layer, dielectric layer, and absorptive layer, where the reflective layer's width is designed to be smaller than the dielectric and absorptive layers, allowing for precise control of absorption axis reflectance by adjusting the etching process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If physical etching technique is used to shape the polarizer pattern, then the wire grid structure can be formed, but the thickness and volume of the absorptive layer fluctuate due to variations in vacuum and gas pressure control, leading to inaccurate control of wavelength dispersion of absorption axis reflectance

Engineering Contradiction:

Improvecontrol of wavelength dispersion of absorption axis reflectanceVSAvoidconsistency of absorptive layer thickness

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The invention changes the etching method from physical etching to chemical etching. Chemical etching uses chemical reactions to remove material, which is less sensitive to vacuum and gas pressure variations compared to physical etching methods. This parameter change in the etching process enables more stable and consistent absorptive layer thickness, thereby achieving accurate control of wavelength dispersion of absorption axis reflectance.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the absorptive layer is constantly etched during shaping, then the wire grid structure can be formed, but the thickness and volume of the absorptive layer fluctuate depending on etching device control variations

Engineering Contradiction:

Improveformation of wire grid structureVSAvoidthickness control of absorptive layer

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the etching mechanism from physical to chemical. Chemical etching provides more uniform material removal rates and is less affected by device control variations such as vacuum and gas pressure. This enables the wire grid structure to be formed while maintaining consistent absorptive layer thickness, resolving the contradiction between ease of manufacture and manufacturing precision.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If the thicknesses of dielectric layer and absorptive layer are adjusted for optimal absorption axis reflectance, then channel control can be performed, but the wavelength range where absorption axis reflectance is minimized fluctuates due to etching variations

Engineering Contradiction:

Improveabsorption axis reflectance optimizationVSAvoidwavelength range control

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

By changing from physical to chemical etching, the invention achieves more precise and stable control of layer thicknesses. Chemical etching provides uniform material removal that is less sensitive to process variations, enabling the wavelength range where absorption axis reflectance is minimized to be precisely controlled at the desired channel wavelengths without fluctuation.

Inventive Principle:

Principle #35Parameter changes

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

This configuration enables more accurate control over the wavelength dispersion of absorption axis reflectance, ensuring optimal optical properties for varying light source spectra across different manufacturers, enhancing transmission axis transmittance and projection brightness.

Implementation Method 1

The inorganic polarizing plate is composed of a reflective layer, a dielectric layer, and an absorptive layer

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

a polarizing plate is an optical element that absorbs polarized light in an absorption axis direction and transmits polarized light in a transmission axis direction

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS11874484B2Polarizing plate, method of manufacturing the same, and optical apparatus

Publication Date: 2024.01.16 DEXERIALS CORP

AI summary

Provided is a polarizing plate 1 having a wire grid structure, the polarizing plate 1 comprising: a transparent substrate 10; and grid protrusions 11 provided over the transparent substrate 10, arranged in an array having a pitch shorter than a wavelength of light in a band to be used, and extending in a predetermined direction, the grid protrusions 11 having a reflective layer 13, a dielectric layer 14, and an absorptive layer 15 that are disposed in this order in a direction away from the transparent substrate 10, and the reflective layer 13 having a maximum width b that is smaller than each of a maximum width of the dielectric layer and a maximum width of the absorptive layer (grid width a). This makes it possible to provide a polarizing plate capable of controlling the wavelength dispersion of absorption axis reflectance more accurately.