Optical Matching Layer for Display Ambient Contrast
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Solution Overview
Problem
Conventional light emitting diode displays face challenges in maintaining high output luminance and ambient contrast ratio due to the absorption of ambient light by light absorption layers, which reduces display quality.
Innovation Solution
The implementation of a display device structure that includes a substrate, a light absorption layer, an optical matching layer, and transparent electrodes, where the optical matching layer is positioned between the light absorption layer and the transparent electrodes to control refractive indices and reflect ambient light, thereby enhancing top output luminance and ambient contrast ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light absorption layer is provided to absorb ambient light, then the ambient contrast ratio is improved, but a portion of the light beams emitted by the light emitting layer is also absorbed by the light absorption layer, resulting in reduced output luminance
Solution Approach 1:
An optical matching layer with refractive index n1 is introduced between the light absorption layer (refractive index n2) and the light emitting layer (refractive index n3), where n2 < n1 < n3. This intermediary layer creates a gradient refractive index structure that reduces optical impedance mismatch, enabling the light absorption layer to selectively absorb ambient light while allowing emitted light beams to pass through with minimal loss.
Solution Approach 2:
The refractive indices of the optical matching layer and light absorption layer are optimized within specific ranges (n2 < n1 < n3, with n1-n2 between 0.05-0.5 and n3-n1 between 0.05-0.5). By adjusting these refractive index parameters, the system achieves optimal balance between ambient light absorption and emitted light transmission, resolving the contradiction between contrast ratio and output luminance.
2Illumination intensity
If the refractive indices of the light absorption layer and optical matching layer are matched, then the ambient contrast ratio is improved, but the output luminance may be reduced due to increased light absorption
Solution Approach 1:
The optical matching layer is designed with specific local optical properties (refractive index n1) that differ from both the light absorption layer (n2) and light emitting layer (n3). This local quality differentiation creates an optical gradient that selectively affects ambient light versus emitted light, improving contrast ratio while preserving output luminance through localized refractive index optimization.
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 effectively increases the ambient contrast ratio and maintains high output luminance by optimizing the refractive indices and thicknesses of the optical matching and light absorption layers, reducing ambient light reflection and improving display quality.
Implementation Method 1
the optical matching layer is positioned between the light absorption layer and the transparent electrodes to control refractive indices and reflect ambient light
Implementation Method 2
the optical matching layer is positioned between the light absorption layer and the transparent electrodes to control refractive indices and reflect ambient light
Implementation Method 3
a light absorption layer is provided to absorb the ambient light
Data Source
AI summary
A display device including a substrate, a light absorption layer, an optical matching layer, a first transparent electrode, a light emitting layer, and a second transparent electrode is provided. The light absorption layer is disposed on the substrate, and the optical matching layer is disposed on the light absorption layer. The first transparent electrode is disposed on the optical matching layer, the light emitting layer is disposed on the first transparent electrode, and the second transparent electrode is disposed on the light emitting layer. An output luminance and a reflectance of ambient light are controlled by adjusting refractive indices of the optical matching layer and the light absorption layer.