Retardation Layer Tuning for Display Panel Color Tone Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices with high external light reflection suffer from deterioration in color tone due to the large magnitude of external light reflection, particularly in organic EL Elements and micro-LED elements, where existing methods like circular polarizing plates often fail to adequately address this issue.
Innovation Solution
Incorporating a retardation layer with specific λ/4 and λ/2 retardation characteristics, where the in-plane retardation of the λ/4 retardation layer falls within a calculated range based on the spectral reflectance ratio (R1/R2) of the display element, effectively suppressing color tone deterioration by optimizing the retardation layer's properties to match the spectral distribution of reflected light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a metal electrode with excellent reflectivity is applied to efficiently use the light of the light emitting layer, then light efficiency is improved, but external light reflection magnitude increases causing contrast deterioration
Solution Approach 1:
A circular polarizing plate is introduced as an intermediary component between the metal electrode and external light sources. This plate converts linearly polarized reflected light into circularly polarized light, effectively reducing the magnitude of external light reflection and preventing contrast deterioration while preserving the high reflectivity of the metal electrode for light efficiency
Solution Approach 2:
The optical parameters of the polarizing plate are specifically optimized by controlling the in-plane retardation within a predetermined range (50 nm to 150 nm) to achieve the desired balance between light efficiency and external light reflection suppression. This parameter optimization ensures the circular polarizing plate effectively manages reflected light without compromising the metal electrode's light efficiency
2Object-affected harmful factors
If a circular polarizing plate is incorporated to suppress external light reflection, then contrast is improved, but color tone deterioration occurs
Solution Approach 1:
The in-plane retardation of the circular polarizing plate is precisely controlled within the range of 50 nm to 150 nm. This parameter optimization ensures that the plate effectively suppresses external light reflection to improve contrast while minimizing adverse effects on color tone. The specific retardation range is determined to balance contrast enhancement with color accuracy
Solution Approach 2:
The polarizing plate is designed with spatially varying optical properties through controlled in-plane retardation distribution. This allows different regions or aspects of the reflected light to be treated differently, suppressing harmful reflections in certain polarization directions while preserving color information in other components, thus preventing color tone deterioration
3Object-affected harmful factors
If a circular polarizing plate is used to suppress external light reflection, then contrast is improved, but viewing angle dependency increases
Solution Approach 1:
The in-plane retardation of the circular polarizing plate is optimized within 50 nm to 150 nm to achieve a balance between contrast improvement and viewing angle performance. This parameter control ensures that the plate effectively reduces external light reflection while maintaining acceptable viewing angle characteristics by managing polarization effects across different observation angles
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 effectively suppresses color tone deterioration in display panels and devices by selecting a retardation layer that aligns with the spectral reflectance characteristics, enhancing the product design and performance by reducing external light reflection impacts.
Implementation Method 1
a retardation layer (B) positioned on the light emission surface side of the display element... the in-plane retardation of the λ/4 retardation layer (B1) satisfies the following Condition (1)
Data Source
AI summary
The present invention provides a display panel in which deterioration of color tone may be suppressed regardless of the reflectance of the display element.A display panel including a display element (A), a retardation layer (B) positioned upon the light emission surface side of the display element, and a polarizer (C) positioned upon the light emission surface side of the retardation layer, in which the retardation layer (B) has a λ/4 retardation layer (B1), and the in-plane retardation of the λ/4 retardation layer (B1) satisfies the following Condition 1:<Condition 1>The spectral reflectance of the display element is measured by an SCI method, the average reflectance at wavelengths over the range of 400 nm or more and less than 550 nm is obtained as R1, the average reflectance at wavelengths over the range of 550 nm or more and less than 700 nm is obtained as R2, and when the value of R1/R2 is calculated and obtained as x, the in-plane retardation of the λ/4 retardation layer falls within the range of −4.6002x+119.24 nm or more and −4.6002x+129.24 nm or less.