Foldable Display Polarizer Alignment for Reflection Color and Blackout Control
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Solution Overview
Problem
Existing foldable displays face challenges in maintaining display quality, including differences in reflection color and visibility issues when viewed at different angles, particularly when users wear polarized sunglasses, and are prone to blackout and rainbow mura phenomena.
Innovation Solution
A foldable display apparatus with a specific configuration of retardation layers and a linear polarizer, where the polarization axis of the linear polarizer is set at 45±5° or 135±5° relative to the folding axis, combined with λ/2 and λ/4 retardation layers, minimizes reflection color differences and enhances visibility by controlling light polarization states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a polarizing film is provided under a window member to improve reflective visibility, then reflective visibility is improved, but display quality deteriorates due to differences in reflection color at different viewing angles
Solution Approach 1:
The patent applies parameter changes by precisely controlling the polarization axis angle of the linear polarizer (set at 45±5° or 135±5° relative to the folding axis) and the optical axes of the retardation layers. This angular parameter optimization minimizes reflection color differences across viewing angles while maintaining high reflective visibility, resolving the contradiction between improved reflectivity and maintained display quality
Solution Approach 2:
The patent employs a composite optical structure consisting of multiple functional layers: a linear polarizer with specific orientation, λ/2 and λ/4 retardation layers with controlled optical axes, and a window member. This composite configuration works synergistically to control polarization states and minimize reflection color variation, achieving both high reflective visibility and consistent display quality across different viewing angles
2Illumination intensity
If conventional polarizing films are used to improve reflective visibility, then reflective visibility is improved, but blackout phenomenon occurs when users wear polarized sunglasses
Solution Approach 1:
The patent changes the polarization parameter by setting the linear polarizer's polarization axis at specific angles (45±5° or 135±5°) relative to the folding axis, rather than conventional orientations. This angular adjustment ensures that reflected light maintains consistent polarization characteristics that are compatible with polarized sunglasses, preventing blackout phenomenon while preserving reflective visibility
Solution Approach 2:
The patent introduces retardation layers as intermediary optical elements between the linear polarizer and the viewer. These layers modify the polarization state of reflected light, acting as a mediator that ensures compatibility with polarized sunglasses and prevents the blackout effect that occurs with conventional polarizing film configurations
3Illumination intensity
If conventional polarizing films are used to enhance reflective visibility, then reflective visibility is improved, but rainbow mura phenomenon occurs when wearing polarized sunglasses
Solution Approach 1:
The patent optimizes the angular parameters of the optical layers, setting the linear polarizer at 45±5° or 135±5° and controlling the optical axes of the retardation layers. This precise parameter control ensures uniform polarization modification across the display surface, eliminating rainbow mura artifacts while maintaining enhanced reflective visibility
Solution Approach 2:
The patent uses a composite structure of multiple optical layers with specific orientations: the linear polarizer, λ/2 and λ/4 retardation layers with controlled optical axes. This composite configuration provides uniform polarization control across the entire display, preventing localized color variations and rainbow mura effects that occur with simpler polarizing film designs
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 solution improves reflective and black visibility by reducing color changes at various viewing angles and prevents blackout and rainbow mura phenomena when wearing polarized sunglasses, ensuring clear image recognition across all viewing angles.
Implementation Method 1
a linear polarizer disposed on the first lower retardation layer, the linear polarizer having a polarization axis of 45±5° or 135±5° with respect to the folding axis of the display panel
Implementation Method 2
a first lower retardation layer on the display panel; a second lower retardation layer between the display panel and the first lower retardation layer
Data Source
AI summary
A foldable display apparatus includes a display panel including a folding area and a non-folding area, the folding area configured to fold about a folding axis, a first lower retardation layer on the display panel, a second lower retardation layer between the display panel and the first lower retardation layer, a linear polarizer disposed on the first lower retardation layer, the linear polarizer having a polarization axis of 45±5° or 135±5° with respect to the folding axis of the display panel, and a window member on the linear polarizer.