Liquid Quantum Dots for Solid State Lighting Efficiency
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Solution Overview
Problem
Current solid state lighting technologies using quantum dots in solid structures have low efficiency, limiting their effectiveness in general lighting applications, whereas quantum dots in liquid form exhibit higher efficiencies but have not been practically utilized in such devices.
Innovation Solution
Incorporating quantum dots in a liquid form within a diffusely reflective optical integrating cavity of a lighting apparatus, where the quantum dots produce a wavelength shift to achieve a desired spectral characteristic for general lighting applications, enhancing light efficiency up to 90%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If quantum dots are integrated directly into the LED package or solid structures, then the device structure is simplified and manufacturing is easier, but the light efficiency is reduced to around 30% or less
Solution Approach 1:
The patent introduces a liquid medium as an intermediary between the quantum dots and the solid LED package. The quantum dots are suspended in a liquid that is contained within a transparent housing or applied as a liquid layer, allowing the quantum dots to maintain their high efficiency (90% or more) while still being integrated with the LED package. This liquid intermediary preserves the quantum dots' optical properties while enabling practical integration.
Solution Approach 2:
The patent changes the physical state of the quantum dot environment from solid to liquid. By suspending quantum dots in a liquid medium rather than embedding them in solid structures, the system maintains the quantum dots' superior light efficiency characteristics while achieving practical integration with LED packages. The liquid state allows for better optical properties and higher efficiency.
2Loss of energy
If quantum dots in liquid are used to achieve high light efficiency, then the light efficiency improves to 90% or more, but the device complexity increases due to the need for liquid containment structures
Solution Approach 1:
The transparent housing serves multiple functions: it contains the liquid medium, protects the quantum dots from degradation, and allows light transmission. By combining containment, protection, and optical transmission functions into a single component, the design minimizes the number of separate parts needed, thereby reducing overall device complexity while maintaining high efficiency.
Solution Approach 2:
The liquid medium serves the quantum dots by providing a stable environment that maintains their high efficiency, while the quantum dots simultaneously provide the light conversion function. The system is designed so that the quantum dots in liquid can be directly applied to or near the LED package, and the liquid itself provides the necessary containment and protection without requiring additional complex structures.
3Device complexity
If quantum dots are coated on the LED package surface, then the integration is simplified, but the spectral characteristics and color output control are limited
Solution Approach 1:
The patent enables dynamic control of spectral characteristics by allowing selective positioning of quantum dots with different size distributions in the liquid medium. Different regions of the liquid can contain quantum dots tuned for different wavelengths, and the liquid's fluidity allows for flexible arrangement and reconfiguration to achieve desired color outputs and spectral characteristics.
Solution Approach 2:
The patent applies quantum dots with specific size distributions to specific regions or wavelengths of the LED output. By having different quantum dot sizes (which emit different wavelengths) in different locations or layers within the liquid medium, the system can precisely control the spectral characteristics and color output, transforming the limited broadband output into a tailored spectrum suitable for various lighting applications.
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 use of quantum dots in a liquid state within a diffusely reflective optical integrating cavity significantly improves light efficiency, providing a uniform and desired spectral characteristic for general lighting applications, such as downlighting and task lighting, while maintaining sufficient intensity.
Implementation Method 1
quantum dot materials in liquid are used to shift at least some electromagnetic energy so that the equipment produces a desired spectral characteristic
Implementation Method 2
AOT has developed a variety of light fixture configurations that utilize a diffusely reflective optical integrating cavity to process and combine the light from a number of solid state sources
Data Source
AI summary
A lighting apparatus includes a source of light of a first spectral characteristic, a reflector or a diffusely reflective chamber or cavity having a transmissive optical passage, and a liquid containing quantum dots. The quantum dots provide a wavelength shift of at least some light emitted by the source of light to produce a desired second spectral characteristic in the light output.