Quantum Dot Color Filter Structure for Higher Purity and Luminance
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Solution Overview
Problem
Existing color filter structures in display devices suffer from low color purity and luminance due to light absorption and total reflection at the interface between the light-conversion layer and the low refractive index layer.
Innovation Solution
A color filter structure is introduced, comprising a light-conversion layer with a core/shell structured quantum dots dispersed in a first resin, and a light-absorbing layer with semiconductor nano-particles dispersed in a second resin, both having the same refractive index to prevent total reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a color filter is used to absorb blue light that passes through the light-conversion layer, then color purity is improved, but luminance is deteriorated due to light absorption
Solution Approach 1:
The color filter is divided into two functional layers: a light-absorbing layer for absorbing blue light (improving color purity) and a light-extraction layer for extracting converted light (maintaining luminance). This segmentation allows each layer to perform its specific function without compromising the other, resolving the contradiction between color purity and luminance
Solution Approach 2:
The light-extraction layer acts as an intermediary between the light-conversion layer and the external environment. It has high light extraction efficiency to capture converted light and prevent total reflection, while allowing the light-absorbing layer to effectively absorb blue light. This intermediary layer resolves the conflict by mediating between light absorption for purity and light extraction for luminance
2Use of energy by moving object
If a low refractive index layer is introduced between the color filter and light-conversion layer to reuse light, then light-conversion efficiency is improved, but luminance improvement is limited due to total reflection at the interface
Solution Approach 1:
The refractive index parameter of the light-extraction layer is optimized to match or exceed the refractive index of the light-conversion layer. This parameter change eliminates total internal reflection at the interface, allowing converted light to be extracted efficiently while maintaining high light-conversion efficiency, thus resolving the contradiction between conversion efficiency and luminance
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 both the color purity and luminance of the emitted light by effectively absorbing unconverted blue light and improving light extraction efficiency.
Implementation Method 1
a light-conversion layer including quantum dots which convert a wavelength of light emitted from a light-emissive element
Implementation Method 2
a light-absorbing layer including semiconductor nano-particles that absorb light emitted from the light-emissive element
Implementation Method 3
a portion of the converted light (red light or green light) is totally reflected from an interface between the light-conversion layer and the low refractive index layer
Data Source
AI summary
Discussed is a color filter structure for converting a wavelength of light emitted from a light-emissive element. The color filter structure includes a light-conversion layer containing a first resin and quantum dots dispersed in the first resin, wherein each quantum dot has a core/shell structure. The color filter structure further includes a light-absorbing layer stacked on the light-conversion layer, wherein the light-absorbing layer contains a second resin and semiconductor nano-particles dispersed in the second resin. The semiconductor nano-particles absorb light emitted from the light-emissive element. Accordingly, the color filter structure improves color purity and luminance of the emitted light.