Curved Display Panel Stress Management via Asymmetric Bending
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Solution Overview
Problem
Curved displays using liquid crystal panels face issues with stress-optical effects due to uneven vertical and horizontal stresses, leading to light leakage and mura (image defects) in dark states, as polarizers cannot filter out light effectively.
Innovation Solution
A display device with a display panel bent in both horizontal and vertical directions, where the backlight module has corner and edge bearing surfaces to distribute stress evenly, reducing phase rotation of polarized light and minimizing light leakage by ensuring the ratio of maximum deflections in both directions falls within specific ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display panel is bent to form a curved surface, then the display surface area is increased and viewing quality is improved, but uneven stresses are generated causing light leakage and mura
Solution Approach 1:
The patent applies different curvature radii to different regions of the display panel. The first and second curvature radii are designed to be different from each other, creating localized variations in bending stiffness and stress distribution. This local differentiation allows the panel to maintain curvature for increased display area while controlling stress concentration to minimize light leakage and mura effects.
Solution Approach 2:
The patent changes the geometric parameters of the curved display panel by defining specific curvature radii (first curvature radius and second curvature radius) and their respective relationships to the panel dimensions. By controlling these parameters within specific ranges, the patent achieves optimal balance between increased display surface area and controlled stress distribution to prevent harmful optical effects.
2Shape
If external forces are applied to bend the liquid crystal panel, then the panel forms a curved surface, but stress-optical effects occur due to different vertical and horizontal stresses
Solution Approach 1:
The patent introduces asymmetric curvature by setting the first curvature radius different from the second curvature radius. This asymmetric bending configuration creates a non-uniform stress distribution pattern that, while still producing curvature, helps balance the vertical and horizontal stress components to reduce stress-optical effects and phase retardation.
Solution Approach 2:
The patent addresses the stress-optical problem by introducing a third dimension of control - the relationship between curvature radii and panel dimensions. By controlling the ratios of curvature radii to panel length and width, the patent creates a multi-parameter optimization that balances curvature formation with stress distribution to minimize harmful optical effects.
3Object-generated harmful factors
If the display panel is bent in multiple directions, then the curvature is controlled to reduce mura, but the manufacturing precision requirements increase
Solution Approach 1:
The patent segments the curvature control into distinct parameters - first curvature radius and second curvature radius - each corresponding to different bending directions. This segmentation allows independent optimization of each curvature component, making the manufacturing process more manageable and less precision-critical while still achieving the overall goal of reducing mura through controlled multi-directional bending.
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 reduces light leakage and minimizes mura in dark states by making vertical and horizontal stress magnitudes closer, enhancing image quality by reducing phase rotation and light leakage.
Implementation Method 1
a stress-optical effect may occur if uneven forces are applied to the display panel. Specifically, because the vertical stress and horizontal stress in the display panel are different, the phase retardation of the vertical polarization or the horizontal polarization of polarized light is generated
Implementation Method 2
the phase retardation of the vertical polarization or the horizontal polarization of polarized light is generated, leading to a slight phase rotation of the polarized light passing through the display panel. Therefore, a polarizer can not entirely filter out light
Data Source
AI summary
A display device includes a display panel and a backlight module. The display panel is bent in a first direction and a second direction perpendicular to the first direction. The backlight module is disposed on one side of the display panel.