Anti-reflective Optical Film for Bendable Displays
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Solution Overview
Problem
Bendable or foldable display apparatuses experience color changes in images due to the bending of optical films, which apply tensile or compressive forces, altering the direction of the slow axis of phase retarders.
Innovation Solution
An optical film with a circular polarizer comprising at least two-phase retarders and a polarizer, where the slow axes of the phase retarders are aligned within the same quadrant of the optical film, minimizing changes in their angles when the display apparatus is bent or folded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the optical film is bent or folded to enable display apparatus flexibility, then the display apparatus can be curved and viewed from various angles, but the bending causes tensile or compressive forces that change the direction of the slow axis of phase retarder, resulting in color change of the displayed image
Solution Approach 1:
The patent applies asymmetry by strategically positioning the slow axes of multiple phase retarders at specific asymmetric angles (e.g., 0°, 60°, 120° or other non-uniform distributions) rather than symmetric arrangements. This asymmetric configuration ensures that when bending forces are applied, the cumulative effect on the overall polarization state remains minimal, thereby preventing color shifts while maintaining display flexibility.
Solution Approach 2:
The patent changes the parameters of the phase retarders by using multiple retarders with different retardation values (e.g., quarter-wave, half-wave) and different slow axis orientations. By adjusting these parameters and their spatial arrangement, the system compensates for the effects of bending-induced stress, maintaining consistent optical performance across flexed and unfolded states.
2Ease of manufacture
If the optical film uses conventional phase retarder configuration, then the manufacturing process is simpler, but the color consistency of the displayed image deteriorates during bending
Solution Approach 1:
The patent segments the optical film into multiple functional layers, each containing phase retarders with specific orientations and retardation values. This segmentation allows each layer to handle specific aspects of polarization control, and when combined, they provide robust color consistency that is resistant to bending-induced changes, while still using standard manufacturing techniques for each individual layer.
Solution Approach 2:
The patent employs a composite structure combining multiple phase retarder materials with different optical properties (different retardation values and slow axis orientations) within a single optical film assembly. This composite approach creates a system where the combined optical effect remains stable under bending, while each component can be manufactured using conventional processes.
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 configuration helps maintain the anti-reflective performance and image color consistency of the display apparatus even when it is bent or folded, by ensuring that the phase retarders' slow axes change direction uniformly.
Implementation Method 1
a circular polarizer including at least two-phase retarders and one polarizer
Data Source
AI summary
A display apparatus includes a display panel configured to display an image. The display panel has a folding axis extending in a first direction. An optical film is disposed over the display panel. The optical film includes a circular polarizer including at least two-phase retarders and one polarizer. Slow axes of each of the at least two-phase retarders are located in the same quadrant of four quadrants of the optical film.