Quantum Dot Display Layer Stack for Light Extraction and Color Purity
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Solution Overview
Problem
Current display devices face challenges in achieving high light efficiency due to limitations in light emission and color conversion, particularly in the design of light-emitting elements and color filter layers, which result in reduced color purity and increased light loss.
Innovation Solution
A display device structure incorporating a light-emitting element layer with an encapsulation layer, a color conversion-transmitting layer using quantum dots, a low-refractive inorganic layer, and a color filter layer, where the low-refractive inorganic layer has a refractive index between 1.2 and 1.4, and a filler with a higher refractive index than the low-refractive inorganic layer, optimized to minimize light loss and enhance color conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional color filter layer is used directly on the light-emitting element, then the structure is simple, but light loss increases and color purity decreases
Solution Approach 1:
The patent divides the color conversion system into multiple functional layers: a color conversion layer with quantum dots for wavelength conversion, a low-refractive inorganic layer for light extraction, and a color filter layer for color purification. This segmentation allows each layer to optimize its specific function, reducing overall light loss while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The low-refractive inorganic layer acts as an intermediary between the color conversion layer and the color filter layer. Its low refractive index (1.2-1.4) creates optimal optical conditions for light extraction and transmission, mediating the optical interaction between the quantum dot layer and color filters to minimize light loss and enhance color purity.
2Manufacturing precision
If quantum dots are used in the color conversion layer, then color purity improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent controls the refractive index parameter of the low-refractive inorganic layer (specifically between 1.2 and 1.4) to optimize optical performance. This parameter control compensates for variations in quantum dot placement and ensures consistent color purity output, reducing the stringency of manufacturing precision requirements while maintaining high color quality.
3Loss of energy
If the refractive index of the inorganic layer is reduced to 1.2-1.4, then light extraction efficiency improves, but material selection becomes more limited
Solution Approach 1:
The patent specifies a precise refractive index range (1.2-1.4) for the inorganic layer to maximize light extraction efficiency. This parameter specification guides material selection toward substances like porous silicon oxide or fluorinated materials that achieve optimal optical performance, balancing the need for high light extraction with practical manufacturing considerations.
Solution Approach 2:
The low-refractive inorganic layer can be implemented as a composite structure, such as porous silicon oxide or silicon oxide combined with fluorinated compounds. These composite materials achieve the target refractive index range while maintaining compatibility with standard semiconductor manufacturing processes, thus improving light extraction without excessively limiting material options.
4Reliability
If multiple encapsulation layers are used to protect the light-emitting element, then reliability improves, but device complexity increases
Solution Approach 1:
The patent combines the encapsulation function with the optical functional layers. The low-refractive inorganic layer and color conversion layer are integrated into a unified structure that simultaneously provides environmental protection and optical performance, reducing the need for separate encapsulation layers and simplifying the overall device structure while maintaining reliability.
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 proposed structure significantly improves light efficiency by reducing light loss and enhancing color purity through the strategic use of quantum dots and refractive index differences, leading to improved display performance.
Implementation Method 1
a color conversion-transmitting layer on the encapsulation layer and configured to convert light emitted from the at least one light-emitting element into light having different colors, the color conversion-transmitting layer including quantum dots
Implementation Method 2
a low-refractive inorganic layer on the color conversion-transmitting layer and having a refractive index less than a refractive index of the color conversion-transmitting layer
Implementation Method 3
a filler between the low-refractive inorganic layer and the color filter layer and having a refractive index greater than a refractive index of the low-refractive inorganic layer
Data Source
AI summary
A display device includes: a first substrate; a second substrate; a light-emitting element layer on the first substrate and comprising at least one light-emitting element; an encapsulation layer on the light-emitting element layer and comprising at least one inorganic encapsulation layer and at least one organic encapsulation layer; a color conversion-transmitting layer on the encapsulation layer and configured to convert light emitted from the at least one light-emitting element into light having different colors, the color conversion-transmitting layer including quantum dots; a low-refractive inorganic layer on the color conversion-transmitting layer and having a refractive index less than a refractive index of the color conversion-transmitting layer; a color filter layer on a surface of the second substrate opposite to the first substrate; and a filler between the low-refractive inorganic layer and the color filter layer and having a refractive index greater than the refractive index of the low-refractive inorganic layer.