Bandpass Polarizing Reflective Layer for OLED Ambient Light Reduction
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Solution Overview
Problem
Organic light-emitting diode (OLED) and micro LED display panels face poor display quality due to reflective electrodes reflecting ambient light, leading to reduced luminous efficiency and contrast, especially in dark states, as existing solutions like circular polarizers compromise optical output.
Innovation Solution
A display apparatus incorporating a circuit substrate, light-emitting layer, polarizing layer, quarter waveplate, and bandpass polarizing reflective layer, where the bandpass polarizing reflective layer is positioned between the quarter waveplate and light-emitting layer to effectively reduce ambient light reflectance and internal light energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a circular polarizer is provided on the light-emitting surface to reduce ambient light reflection, then the display quality in dark state is improved, but the overall optical output is reduced by at least 55%
Solution Approach 1:
The invention divides the reflective layer into multiple segments: a first reflective layer (circular polarizer) and a second reflective layer (bandpass filter reflective layer). Each layer handles specific wavelength ranges, with the first layer addressing general ambient light reflection and the second layer specifically targeting the light-emitting wavelength range to minimize energy loss while maintaining reflection reduction effectiveness.
Solution Approach 2:
The bandpass filter reflective layer is selectively positioned to overlap only with specific light-emitting structures (e.g., red light-emitting structures) rather than all light-emitting structures. This localized application ensures that reflection is reduced only where needed for specific colors, preserving optical output for other wavelengths that do not require such treatment.
2Use of energy by moving object
If reflective electrodes are used on the back side of the light-emitting diode to increase luminous efficiency, then the luminous efficiency is improved, but the display quality deteriorates due to ambient light reflection
Solution Approach 1:
The reflective electrode system is segmented into multiple layers with different functions: the first reflective layer (circular polarizer) handles general reflection, while the second reflective layer (bandpass filter reflective layer) specifically addresses the wavelength range of emitted light. This segmentation allows the system to maintain high luminous efficiency by reflecting emitted light back into the display structure while simultaneously reducing ambient light reflection that degrades display quality.
Solution Approach 2:
The bandpass filter reflective layer acts as an intermediary between the light-emitting structures and the ambient environment. It selectively reflects light within the specific wavelength range of the light-emitting structures back into the display, enhancing luminous efficiency, while its bandpass characteristics prevent it from reflecting ambient light outside this range, thereby reducing the harmful reflection effect.
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 enhances light energy utilization and improves display quality in dark states by minimizing ambient light reflection and internal light loss, maintaining optical output while reducing reflectance.
Implementation Method 1
The circular polarizer transforms the passing ambient light into circularly polarized light
Implementation Method 2
The quarter waveplate is disposed between the polarizing layer and the light-emitting layer
Implementation Method 3
The bandpass polarizing reflective layer includes a first bandpass polarizing reflective pattern overlapping the first light-emitting structures. The reflectance of the first bandpass polarizing reflective pattern for light with a wavelength in the first wavelength range is greater than 20%.
Implementation Method 4
The light-emitting structures are electrically connected to the circuit substrate and include a plurality of first light-emitting structures. The first light-emitting structures have a first peak emission wavelength.
Data Source
AI summary
Provided is a display apparatus including a circuit substrate, a light-emitting layer, a polarizing layer, a quarter waveplate, and a bandpass polarizing reflective layer. The light-emitting layer includes a plurality of first light-emitting structures. The first light-emitting structures have a first peak emission wavelength. The polarizing layer is located on a side of the light-emitting layer away from the circuit substrate. The quarter waveplate is disposed between the polarizing layer and the light-emitting layer and overlaps the light-emitting layer and the polarizing layer. The bandpass polarizing reflective layer is disposed between the quarter waveplate and the light-emitting layer and includes a first bandpass polarizing reflective pattern overlapping the first light-emitting structures. A reflectance of the bandpass polarizing reflective pattern for light with a wavelength in a first wavelength range is greater than 20%. The first wavelength range is the peak emission wavelength ±10 nm.