Wire Grid Polarizer Adhesion in Retardation-Layer Displays
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Solution Overview
Problem
Existing display devices, particularly those used in head-mounted displays, face challenges in achieving high adhesive strength between retardation layers and wire grid polarizers, leading to film lifting defects.
Innovation Solution
The display device incorporates a wire grid polarizer with a specific metal and grid pattern configuration, including a capping layer made of silicon nitride, silicon oxide, or silicon oxynitride, and metal patterns of titanium, chromium, nickel, tantalum, or tungsten, with varying thicknesses and widths to enhance adhesive strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional wire grid polarizer structure is used, then the device structure is simple, but the adhesive strength between retardation layer and wire grid polarizer is insufficient causing film lifting defects
Solution Approach 1:
The wire grid polarizer is segmented into multiple functional layers: a base layer, a metal pattern layer with specific thickness (50-200 nm), and a grid pattern layer. This segmentation allows each layer to contribute specifically to adhesive strength while maintaining overall structural functionality.
Solution Approach 2:
The invention uses composite material structures combining different materials with complementary properties: transparent conductive oxides (ITO, IZO) for the metal pattern layer provide both conductivity and adhesion, while dielectric materials form the grid pattern. This composite approach enhances adhesive strength without compromising optical performance.
2Strength
If the metal pattern thickness is increased to improve adhesive strength, then adhesive strength improves, but light transmission decreases
Solution Approach 1:
The metal pattern thickness is precisely controlled within the range of 50-200 nm, representing an optimized parameter that balances adhesive strength and light transmission. This specific thickness range provides sufficient adhesion while maintaining high transparency in the visible spectrum.
Solution Approach 2:
The metal pattern is designed with local variations in thickness and distribution, being thicker in regions requiring enhanced adhesion and thinner in regions prioritizing light transmission. This local quality optimization allows simultaneous achievement of both adhesive strength and optical performance.
Data Source
AI summary
A display device and an optical device are provided. The display device includes a display element layer disposed on a substrate, the display element layer including a first electrode, a light emitting layer, and a second electrode, a retardation layer disposed on the display element layer, the retardation layer including at least a capping layer, and a wire grid polarizer disposed on the retardation layer, the wire grid polarizer including a wire grid pattern in which a metal pattern and a grid pattern are stacked each other, the metal pattern is disposed on the capping layer, and has a thickness in a range of about 3 nm to about 7 nm.