Wire Grid Polarizer Spacing for LCD Light Efficiency
Solution Overview
Problem
Liquid crystal display (LCD) devices face reduced light efficiency and brightness due to light absorption by polarizers and crosstalk between metallic materials and switching elements, leading to suboptimal image quality.
Innovation Solution
The implementation of a wire grid polarizer with metal patterns spaced apart by a predetermined interval on the facing substrate, which improves light transmission and reflection efficiency while maintaining electronic properties of the thin film transistor (TFT) by spacing it away from the polarizer, reducing crosstalk and enhancing image brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a PVA polarizer is used to polarize light, then polarization ratio is improved, but light transmissivity deteriorates (about 50% light loss)
Solution Approach 1:
The polarizer is segmented into multiple thin metal wire layers (e.g., three layers) spaced apart from each other, rather than using a single thick PVA layer. This segmentation allows light to pass through the gaps between wires while still achieving polarization, significantly reducing light absorption loss.
Solution Approach 2:
The patent replaces the organic PVA material-based polarizer with a wire grid polarizer made of metal wires. This substitution eliminates the high light absorption characteristic of PVA while maintaining polarization functionality through the geometric arrangement of metal wires.
2Measurement precision
If metallic material is used in the polarizer to enhance polarization ratio and light transmissivity, then polarization performance is improved, but crosstalk occurs between metallic material and switching element
Solution Approach 1:
A dielectric layer is introduced as an intermediary between the metal wire polarizer and the underlying transparent electrode/TFT structure. This dielectric layer electrically isolates the metal wires from the switching elements, preventing crosstalk while allowing the polarizer to function effectively.
Solution Approach 2:
The patent addresses the crosstalk issue by introducing a vertical dimension separation - placing the metal wire polarizer at a different vertical level (z-dimension) from the TFT switching elements, with dielectric layers in between. This spatial separation in the vertical dimension eliminates electromagnetic interference while maintaining horizontal polarization functionality.
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 solution enhances light usage efficiency and reduces crosstalk, resulting in improved image brightness and quality by effectively managing light transmission and reflection within the LCD device.
Implementation Method 1
a first polarizer disposed on the second substrate. The first polarizer may include a plurality of metal patterns spaced apart from each other by a predetermined interval
Implementation Method 2
improves light transmission and reflection efficiency
Implementation Method 3
about half of the light provided from the light source may be absorbed by the PVA polarizer
Data Source
AI summary
A liquid crystal display device includes a liquid crystal display panel and a backlight unit providing light to the liquid crystal display panel. The liquid crystal display panel includes a first substrate on which a thin film transistor is disposed, a second substrate facing the first substrate, a liquid crystal layer disposed between the first substrate and the second substrate, and a first polarizer disposed on the second substrate having a plurality of metal patterns spaced apart from each other by an interval. The backlight unit faces the second substrate.