Wire Grid Polarizer with Corrugated Protrusions for High Transmittance

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Solution Overview

Problem

Existing wire grid polarizing elements face limitations in achieving high polarization degrees and transmittance while maintaining structural stability and ease of production, particularly due to constraints in substrate uneven structure formation and conductor layer deposition methods.

Innovation Solution

A wire grid polarizing element with a substrate having a continuous corrugated shape and a conductor layer that covers the substrate surface excluding convex portion tips, with specific ratios of period, depth, and conductor layer occupancy, formed using physical deposition or electroless plating methods, ensuring high polarization and transmittance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the width of conductive wire is reduced to increase transmittance, then transmittance is improved, but shielding performance deteriorates

Engineering Contradiction:
ImprovetransmittanceVSAvoidshielding performance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The invention transitions from a two-dimensional wire grid structure to a three-dimensional protruding structure. The conductor layer forms protrusions that extend toward the incident light direction, creating a vertical dimension that enhances shielding performance without increasing the horizontal wire width, thus maintaining high transmittance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention changes the geometric parameters of the conductor structure by controlling the height, width, and spacing of the protrusions. By optimizing these parameters, the structure achieves both high transmittance (through narrow spacing) and effective shielding (through sufficient protrusion height), resolving the contradiction between the two performance metrics.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the thickness of conductor layer is increased to improve shielding performance, then shielding performance is improved, but transmittance deteriorates

Engineering Contradiction:
Improveshielding performanceVSAvoidtransmittance
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

Instead of increasing the horizontal thickness of the conductor layer which would block more light, the invention increases the vertical height of conductor protrusions. This dimensional change allows the shielding function to be enhanced without compromising transmittance, as the protrusions intercept polarized light vertically while leaving horizontal gaps for light transmission.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If oblique deposition method is used to form conductor on side surfaces, then conductor coverage is improved, but structural complexity increases

Engineering Contradiction:
Improveconductor coverageVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention forms the protruding conductor structures first, then applies a simple planar deposition layer that naturally conforms to the existing topography. This preliminary formation of the 3D structure simplifies the subsequent deposition process, avoiding the need for complex oblique deposition angles while achieving complete side surface coverage.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If period of uneven structure is reduced to improve polarization degree, then polarization degree is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvepolarization degreeVSAvoidperiod control precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention optimizes the period parameter within a specific range (50-200 nm) rather than using extremely small values. This parameter optimization achieves high polarization degree (90% or more) while maintaining feasible manufacturing precision, resolving the contradiction between performance and manufacturability.

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

The solution achieves improved polarization degree and transmittance, along with enhanced structural stability and ease of production, making it suitable for various optical applications.

Implementation Method 1

light of an electric field component parallel to the wire-shaped objects is reflected or absorbed

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

light of an electric field component parallel to the wire-shaped objects is reflected or absorbed

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

Implementation Method 3

a physical deposition method of introducing a deposition material from above in a direction perpendicular to a substrate surface

Methodology Applied
Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Data Source

PatentEP4579291A1Wire grid type polarizing element and manufacturing method thereof
Publication Date: 2025.07.02 SUMITOMO BAKELITE CO LTD
  • EP4579291A1 patent drawingFigure 1(1)~1(3)
  • EP4579291A1 patent drawingFigure 2(1)~2(4)
  • EP4579291A1 patent drawingFigure 3~4

AI summary

Provided are a wire grid polarizing element having an excellent polarization degree and a high polarized light transmittance in a perpendicular direction, and a method for producing the same. The wire grid polarizing element includes: a substrate that is molded such that a transparent sheet surface has a continuous corrugated shape in cross-section; and a conductor layer that covers a conductor protrusion portion and a surface portion excluding a tip portion having a corrugated shape, the conductor protrusion portion protruding from the tip portion in a tip direction continuous to a direction perpendicular to an arrangement direction. A period (a) of the corrugated shape is 100 to 400 nm, an average depth (b) from the convex portion tip portion to a valley portion of a concave portion in the corrugated shape is 200 to 600 nm, an average occupancy ([2d/a] × 100) of the conductor layers represented by a ratio of an average width (d) in the arrangement direction of two conductor layers present in one period to the period (a) is 18 to 40%, and an average thickness (h) in the tip direction of the conductor protrusion portion is 1.5 times or more the average width (d) of the conductor layers.