Under-Display Camera Phase Retardation Layers for Rainbow Mura
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Solution Overview
Problem
Current foldable screens suffer from rainbow mura when taking pictures due to the phase retardation effect of protective film layers and polarization effects of polarizing layers and lenses.
Innovation Solution
A display device with a first phase retardation layer on one side of the display functional layer and a second phase retardation layer between the display functional layer and the camera module, where the sum of their phase retardation values exceeds 8000 nm, to eliminate interference phenomena and prevent rainbow mura.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protective film layers with high phase retardation are used on foldable screens, then the protective function and display quality are improved, but rainbow mura occurs when taking pictures due to phase change of natural light and polarization effects
Solution Approach 1:
The patent converts the harmful phase retardation effect into a beneficial one by intentionally introducing a second phase retardation layer with specific retardation value (greater than 8000 nm) that compensates for the phase change caused by the protective film layer. This transforms the original harmful interference pattern into a beneficial compensation mechanism that eliminates rainbow mura while maintaining protective functionality.
Solution Approach 2:
The patent changes the phase retardation parameter by adding a second phase retardation layer with a specifically designed retardation value greater than 8000 nm. This parameter change compensates for the phase shift introduced by the protective film layer, thereby eliminating the rainbow mura effect while preserving the protective function.
2Reliability
If polarizing layers and lenses are used in the display device, then the display quality and camera function are improved, but phase change of natural light causes interference phenomena
Solution Approach 1:
The patent converts the harmful interference phenomena generated by the interaction of polarizing layers and lenses with phase-changed light into a beneficial effect. By introducing a second phase retardation layer with retardation value greater than 8000 nm, the patent compensates for the phase change, transforming the interference problem into a solution that eliminates rainbow mura while maintaining display and camera quality.
Solution Approach 2:
The second phase retardation layer acts as an intermediary element between the protective film layer and the camera module. It mediates the phase relationship by introducing a controlled phase delay greater than 8000 nm, which compensates for the phase change caused by the protective film and polarizing layers, thereby eliminating interference phenomena.
3Object-affected harmful factors
If a second phase retardation layer with high retardation value is added to compensate phase change, then rainbow mura is eliminated, but the device structure and manufacturing complexity increase
Solution Approach 1:
The patent applies local quality by positioning the second phase retardation layer specifically in the camera under display (CUD) region where rainbow mura occurs. Rather than uniformly treating the entire display, the phase compensation is locally applied to the area where it is most needed, thereby eliminating rainbow mura while minimizing the increase in overall device complexity.
Solution Approach 2:
The patent uses composite material structure by combining the protective film layer with a second phase retardation layer that has different optical properties (retardation value greater than 8000 nm). This composite structure achieves phase compensation and rainbow mura elimination while integrating multiple functions into a unified layer system.
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 effectively eliminates rainbow mura by ensuring phase delay of natural light exceeds 8000 nm, improving display and photographing quality by stabilizing the display effect.
Implementation Method 1
a first phase retardation layer disposed on one side of the display functional layer in a light-emitting direction; a second phase retardation layer disposed between the display functional layer and the camera module. the first phase retardation layer has a first phase retardation value, the second phase retardation layer has a second phase retardation value, and a sum of the first phase retardation value and the second phase retardation value is greater than 8000 nm
Data Source
AI summary
A display device includes a display functional layer, a first phase retardation layer disposed on one side of the display functional layer in a light-emitting direction, a camera module disposed on one side of the display functional layer away from the light-emitting direction, and a second phase retardation layer disposed between the display functional layer and the camera module. A sum of a phase retardation value of the first phase retardation layer and a phase retardation value of the second phase retardation layer is greater than 8000 nm.