Cadmium-Free Luminescent Nanostructures for Display Panel Efficiency
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Solution Overview
Problem
Current display technologies face challenges in achieving high luminous efficiency and light conversion rates without using harmful heavy metals like cadmium, and they struggle with unnecessary color conversion of green light, leading to decreased efficiency in display panels.
Innovation Solution
A display panel design incorporating a light emitting panel that emits a mix of blue and green light, combined with a color conversion panel featuring luminescent nanostructures made from cadmium-free Group III-V compounds, which are optimized to minimize spectral overlap and enhance absorbance, thereby improving light conversion and reducing unnecessary color conversion of green light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If luminescent nanostructures with high absorbance are used to improve light conversion, then luminous efficiency is improved, but spectral overlap causes unnecessary reabsorption of green light leading to decreased efficiency
Solution Approach 1:
The patent optimizes the spectral characteristics of luminescent nanostructures by adjusting their emission peak wavelength and absorbance profile. Specifically, it controls the ratio B/A where B is the overlap area between nanostructure absorption and green light emission (≥500nm), and A is the overlap area between nanostructure absorption and blue light emission (≤500nm), maintaining B/A ≤ 0.6. This parameter optimization ensures high absorbance for blue light conversion while minimizing reabsorption of green light, thereby improving luminous efficiency and reducing energy loss simultaneously.
2Ease of manufacture
If traditional phosphors are used to achieve color conversion, then color conversion is achieved, but harmful heavy metals like cadmium are used reducing reliability
Solution Approach 1:
The patent replaces traditional cadmium-based phosphors with cadmium-free luminescent nanostructures, specifically using Group III-V compound semiconductor nanocrystals (such as InP, InGaP, InZnP). These alternative materials achieve comparable or superior optical properties including high quantum yield and tunable emission wavelengths in the green region (500-580nm), while eliminating the environmental and health hazards associated with heavy metals, thus improving reliability without sacrificing color conversion capability.
Solution Approach 2:
The patent employs composite material structures, specifically core-shell type luminescent nanostructures where a Group III-V compound semiconductor core is combined with appropriate shell materials. This composite approach enables precise control over optical properties, enhances quantum yield, provides surface passivation to reduce non-radiative recombination, and eliminates the need for harmful cadmium while maintaining excellent color conversion performance.
3Device complexity
If blue light emitting panels are used to simplify structure, then device complexity is reduced, but luminous efficiency decreases due to insufficient green light conversion
Solution Approach 1:
The patent introduces luminescent nanostructures as an intermediary material between the blue light emitting panel and the human eye. These nanostructures act as a spectral converter that absorbs blue light (≤500nm) and emits green light (≥500nm) with optimized spectral characteristics. By carefully controlling the absorption and emission spectra of this intermediary layer, the system achieves high luminous efficiency with a simplified blue-only light emitting structure, avoiding the need for complex multi-layer phosphor systems.
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 solution achieves improved luminous efficiency and reduced reabsorption of green light, leading to enhanced display quality and efficiency by carefully controlling the spectral overlap and absorbance properties of the luminescent nanostructures, thus overcoming the limitations of existing technologies.
Implementation Method 1
the spectral overlap between a UV-Vis absorption spectrum of the luminescent nanostructures, the maximum emission peak of the first light, and the maximum emission peak of the second light
Implementation Method 2
The plurality of luminescent nanostructures may be configured to convert the emission spectrum of the incident light
Data Source
AI summary
A display panel including a light emitting panel; and a color conversion panel with a surface opposite a surface of the light emitting panel. The light emitting panel is configured to emit incident light including a first light and a second light. The color conversion panel includes a color conversion layer including two or more color conversion regions, a color conversion region includes a first region corresponding to the green pixel, the first region includes a matrix and a first composite dispersed within the matrix and including a plurality of luminescent nanostructures, and the spectral overlap between a UV-Vis absorption spectrum of the luminescent nanostructures, the maximum emission peak of the first light, and the maximum emission peak of the second light satisfies the following equation:B/A≤about 0.6A and B are as defined.