Optical Filter Capping Layer for Display Light Efficiency
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Solution Overview
Problem
Current display devices face challenges in achieving high light-emission efficiency and reducing external light reflectivity, which affect their display quality.
Innovation Solution
An optical filter is designed with a substrate, filter layer, light-converting layer, low refractive index layer, and capping layers, including a buffer layer and light-blocking patterns, to enhance light conversion efficiency and reduce external light reflection. The filter includes color filters and light-converting portions with quantum dots, and a barrier layer to prevent color mixing and improve light utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light-converting layer with quantum dots is used to convert light wavelengths, then color accuracy is improved, but external light reflectivity increases
Solution Approach 1:
A low refractive index layer is introduced as an intermediary between the filter layer and the light-converting layer. This layer has a refractive index lower than both adjacent layers, creating a gradient that reduces external light reflectivity while allowing the quantum dots in the light-converting layer to maintain their color conversion function. The intermediary layer acts as a refractive index bridge that mitigates the harmful reflection effect.
2Object-affected harmful factors
If multiple layers with different refractive indexes are stacked to reduce reflection, then external light reflectivity is reduced, but device complexity increases
Solution Approach 1:
Instead of uniformly complex anti-reflection structures across the entire device, the invention applies a specific low refractive index layer configuration only where needed - between the filter layer and light-converting layer. This localized application of refractive index gradient reduces external light reflectivity at the critical interface without unnecessarily complicating the entire device structure.
3Manufacturing precision
If a buffer layer is added to cover the filter layer, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
A buffer layer is applied in advance to cover the filter layer before forming the light-converting layer. This preliminary action provides a flat, stable surface that improves the precision of subsequent manufacturing steps, particularly the formation of the quantum dot pattern. The buffer layer serves as a foundation that ensures accurate positioning and uniform thickness of overlying layers.
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 optical filter significantly improves light-emission efficiency and display quality by increasing brightness and reducing external light reflection, resulting in enhanced visibility and color accuracy.
Implementation Method 1
a low refractive index layer between the filter layer and the light-converting layer and having a refractive index less than a refractive index of the light-converting layer
Implementation Method 2
A quantum dot is excited by incident light and emits light having a wavelength longer than a wavelength of the incident light
Data Source
AI summary
An optical filter includes a substrate, a filter layer on the substrate and including color filters, and a light-converting layer over the filter layer and including light-converting portions respectively corresponding to the color filters. A low refractive index layer is between the filter layer and the light-converting layer and has a refractive index less than a refractive index of the light-converting layer. A first capping layer is between the low refractive index layer and the light-converting layer and has a refractive index ranging between the refractive index of the light-converting layer and the refractive index of the low refractive index layer.