Wire Grid Polarizer Trench Segmentation for Defect Reduction
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Solution Overview
Problem
Large wire grid polarizers for display devices face challenges in fabrication due to defects caused by stitch lines between metal patterns, leading to degraded polarization properties, especially when using nano-imprint technology for large-scale production.
Innovation Solution
A wire grid pattern with trench areas between cells is introduced, featuring a substrate with cells having wires arranged in parallel and slits, along with a bezel area including a trench area that separates cells and accommodates excessive resin, reducing defects during the fabrication process. The method involves forming a metal layer, applying resin, and etching using resin patterns to create the wire grid pattern, allowing for improved polarization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a large wire grid polarizer is fabricated using nano-imprint technology with repeating small molds, then the manufacturing cost and difficulty are reduced, but defects occur in the connection area (stitch line) between metal patterns causing degraded polarization property
Solution Approach 1:
The invention divides the large wire grid polarizer into multiple cell areas, each fabricated independently using small molds. The trench areas separate these cells, allowing independent fabrication while maintaining overall functionality. This segmentation enables the use of small, manageable molds rather than requiring a single large mold, thus improving ease of manufacture.
Solution Approach 2:
The trench areas act as intermediary regions between adjacent cell areas. These trenches accommodate excessive resin and prevent defects from propagating across cell boundaries. By introducing this intermediary structure, the invention eliminates the harmful stitch line defects that would otherwise occur at connection areas between repeatedly fabricated sections.
2Reliability
If a large wire grid polarizer is fabricated using a single large mold, then polarization property is maintained, but the fabrication becomes difficult and expensive
Solution Approach 1:
The invention segments the large polarizer structure into multiple smaller cell areas that can be fabricated using small, manageable molds. Each cell maintains the necessary wire grid pattern for polarization, and the overall large-area functionality is achieved by arranging multiple cells together with trench areas in between.
Solution Approach 2:
The invention uses small molds to create identical copies of the wire grid pattern in multiple cell areas. Rather than fabricating the entire large polarizer in one step with a large mold, the small mold is repeatedly used to create copies of the pattern across the substrate, achieving large-area coverage through replication.
3Reliability
If trench areas are introduced to separate cells, then defects in connection areas are reduced, but the device structure becomes more complex
Solution Approach 1:
The invention extracts the problematic connection areas (stitch lines) by introducing trench areas that physically separate adjacent cell areas. This extraction removes the source of defects from the structure. The trenches accommodate excessive resin and prevent defect propagation, thereby reducing defects while adding a relatively simple structural element.
Solution Approach 2:
The trench areas are strategically placed only in specific locations where defects would occur (between cell areas), rather than uniformly across the entire structure. This localized approach addresses the defect problem only where needed, minimizing the added structural complexity while maintaining effectiveness.
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 proposed solution enhances the reflection efficiency in non-transmissive areas and maintains high transmittance and polarization properties in transmissive areas, reducing defects and improving the overall performance of the wire grid polarizer.
Implementation Method 1
a wire grid pattern used to polarize light emitted from pixels in a display device
Implementation Method 2
a bezel area disposed along a periphery of the cell area, which includes a trench area separating at least some of the plurality of cells
Data Source
AI summary
A wire grid pattern used as a wire grid polarizer included in a display device or a master substrate for fabricating the wire gird polarizer includes a substrate; a cell area having a plurality of cells, each of the plurality of cells having a plurality of wires protruding from the substrate and arranged in a substantially parallel relationship at regular intervals; and a bezel area disposed along a periphery of the cell area. The cell area includes a trench area separating at least some of the cells. A method for fabricating the wire grid pattern also is disclosed.