Quantum Dot Sheet Edge Phosphor Pattern for LCD Color Purity
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Solution Overview
Problem
Liquid crystal displays face challenges with non-uniform luminance and color purity due to the use of cold cathode fluorescent lamps, and while white LEDs improve economic efficiency, they compromise on color reproducibility and purity compared to three-color LEDs.
Innovation Solution
A quantum dot sheet is developed with a color conversion film, barrier films, and a phosphor pattern printed on its edges to prevent oxidation and enhance light conversion, including quantum dots dispersed in a polymer layer and barrier films made from materials like PET and PC, with inorganic oxides for protection, and phosphor materials like garnet and nitride-based phosphors for edge protection and light conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a white LED is used to convert light from a mono-color LED chip into white light, then economic efficiency is improved, but color reproducibility and color purity deteriorate
Solution Approach 1:
The patent uses a composite structure combining quantum dots (for color conversion) with a white LED (for light generation). The quantum dots are dispersed in a polymer layer to form a color conversion film that converts the blue light from the LED into white light with improved color reproducibility and purity, while maintaining the economic efficiency of using a single-color LED source
Solution Approach 2:
The patent applies phosphor material specifically at the edge portions of the quantum dot sheet where oxidation is most likely to occur. This localized application of protective phosphor material prevents functional deterioration at critical areas without requiring phosphor coating on the entire surface, thus maintaining color purity while providing targeted protection
2Reliability
If phosphor is printed onto edge surfaces of the quantum dot sheet, then functional deterioration from oxidation is prevented, but device complexity increases
Solution Approach 1:
The patent applies phosphor material specifically at the edge portions of the quantum dot sheet where oxidation is most likely to occur. This localized application provides targeted protection against oxidation at critical areas without requiring phosphor coating on the entire surface, thus maintaining reliability while minimizing added complexity
Solution Approach 2:
The phosphor material is applied in advance to the edge surfaces of the quantum dot sheet before the product is put into service. This preliminary protective action prevents oxidation from occurring in the first place, thereby maintaining reliability without requiring complex protective mechanisms during operation
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 quantum dot sheet effectively converts light into white light with improved color reproducibility and purity, preventing functional deterioration from oxidation and offering cost competitiveness by maintaining performance even when oxidation occurs at the edges.
Implementation Method 1
a quantum dot sheet in which phosphor is printed onto an edge surface of the quantum dot sheet... a color conversion film that includes quantum dots and a polymer layer in which the quantum dots are dispersed
Implementation Method 2
a phosphor pattern that has a first portion located along an edge portion of a surface of the first barrier film
Data Source
AI summary
According to an exemplary embodiment, the present system and method provide a quantum dot sheet including: a color conversion film that includes quantum dots and a polymer layer in which the quantum dots are dispersed; a first barrier film that is provided one a planar surface of the color conversion film; and a phosphor pattern that has a portion located along an edge portion of the surface of the first barrier film. The phosphor pattern, which may be printed onto the quantum dot sheet, prevents deterioration of the color conversion performance of the quantum dot sheet that may occur due to oxidization.