LC Panel Phase Plates Negative Retardation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display panels with transverse electrical field mode face challenges in achieving high light usage efficiency, brightness contrast ratio, and low viewing angle dependence of γ properties, particularly in bright environments, due to high transmittance in black display states when viewed obliquely.
Innovation Solution
A liquid crystal display panel configuration featuring a liquid crystal cell with a bottom-side and top-side substrate, a liquid crystal layer, and an electrode pair generating a transverse electrical field, along with specific polarizing and phase difference plates to optimize in-plane and thickness direction retardations, ensuring the slow axes of phase difference plates are parallel and orthogonal to the liquid crystal director, enhancing light usage and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a circular polarizing plate is provided on the backlight side to prevent reflection, then reflection is reduced and image quality is improved, but light usage efficiency decreases because reflected light is not reused
Solution Approach 1:
The patent converts the harmful reflected light into a beneficial resource by using a specific phase difference plate configuration (with negative thickness direction retardation) to redirect reflected light back through the liquid crystal layer, transforming waste light into useful display light that contributes to the image
2Illumination intensity
If the pixel aperture ratio is increased to improve display luminance, then brightness is improved, but the resolution decreases
Solution Approach 1:
The patent changes the optical parameters of the phase difference plates, specifically introducing a negative thickness direction retardation value, which alters the light modulation characteristics to improve luminance efficiency without requiring larger pixel aperture ratios, thus maintaining resolution
3Illumination intensity
If the brightness of the backlight is increased to improve contrast ratio in bright environments, then display luminance is improved, but energy consumption increases
Solution Approach 1:
The patent optimizes the optical parameters of the phase difference plates (in-plane and thickness direction retardations) to improve light modulation efficiency, allowing for reduced backlight brightness while maintaining display luminance and contrast ratio, thus lowering energy consumption
4Illumination intensity
If the transmittance in black display state is reduced to improve contrast ratio, then black display quality is improved, but viewing angle dependence increases
Solution Approach 1:
The patent uses a composite optical structure combining multiple phase difference plates with specific retardation characteristics (including negative thickness direction retardation) to achieve both low black level transmittance and reduced viewing angle dependence, creating a synergistic effect that satisfies both requirements
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 configuration results in improved light usage efficiency, higher brightness contrast ratio, and reduced viewing angle dependence of γ properties, achieving better black display quality even at oblique angles.
Implementation Method 1
The liquid crystal layer includes a nematic liquid crystal and has a homogeneous alignment when no electrical field is applied, and Δnd is greater than or equal to 360 nm and less than or equal to 490 nm, where Δn represents a birefringence of the nematic liquid crystal
Implementation Method 2
An in-plane retardation R1 of the first phase difference plate is greater than or equal to 100 nm and less than or equal to 160 nm. A thickness direction retardation of at least one of the first phase difference plate and the second phase difference plate has a negative value
Implementation Method 3
a first polarizing plate disposed on an observer side of the liquid crystal cell; a second polarizing plate disposed on a back surface side of the liquid crystal cell
Implementation Method 4
an electrode pair, the top-side substrate being disposed on an observer side of the bottom-side substrate, the liquid crystal layer being provided between the bottom-side substrate and the top-side substrate, and the electrode pair being formed on one of the bottom-side substrate and the top-side substrate and generating a transverse electrical field in the liquid crystal layer
Data Source
AI summary
A liquid crystal display panel (100A) includes a first polarizing plate (22) and a first phase difference plate (32a) disposed on an observer side, and a second polarizing plate (24) and a second phase difference plate (34a) disposed on a back surface side. Δnd of a liquid crystal layer having a homogeneous alignment when no electrical field is applied is 360 nm or greater and 490 nm or less, and an in-plane retardation R1 of the first phase difference plate is 100 nm or greater and 160 nm or less. A thickness direction retardation of at least one of the first and second phase difference plates has a negative value. The slow axes of the first and second phase difference plates are substantially parallel to each other and substantially orthogonal to an azimuthal direction of the liquid crystal director.