LED Lighting Device with Phosphor Mixing for High CRI
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lighting technologies, such as incandescent and fluorescent bulbs, are inefficient in energy usage and have limitations in color rendering index (CRI), lifespan, and maintenance, particularly in difficult-to-reach locations, necessitating the development of more energy-efficient and long-lasting alternatives like light-emitting diodes (LEDs) that can produce white light effectively.
Innovation Solution
The integration of LEDs with luminescent materials, such as phosphors, to create lighting devices that achieve high CRI and efficacy by emitting a mixture of light with specific chromaticity coordinates on the CIE Chromaticity Diagram, allowing for the production of white light and improved color rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If incandescent light bulbs are used, then color rendering index (CRI) is high (Ra > 95), but energy efficiency is very low (90% of electricity released as heat)
Solution Approach 1:
The patent changes the fundamental operating parameters of light generation by transitioning from thermal radiation (incandescent) to electroluminescence (LED). This parameter change enables direct conversion of electrical energy to light energy with minimal heat generation, resolving the contradiction between energy efficiency and heat release.
Solution Approach 2:
The patent replaces the thermal-mechanical system of incandescent bulbs with a solid-state electronic system using LEDs and phosphors. This substitution eliminates the need for heating elements and thermal radiation processes, achieving high energy efficiency while minimizing harmful heat release.
2Use of energy by moving object
If fluorescent light bulbs are used, then energy efficiency improves (10x better than incandescent), but color rendering index (CRI) deteriorates (Ra of 70-80)
Solution Approach 1:
The patent segments the light generation process into two independent components: LEDs that provide energy-efficient excitation and phosphors that provide accurate color rendering. This segmentation allows each component to optimize its function, with LEDs converting electricity to light efficiently and phosphors converting that light to broad-spectrum visible light with high CRI.
Solution Approach 2:
The patent uses composite phosphor materials with different emission characteristics to achieve high CRI. By combining multiple phosphors with complementary emission spectra, the system reproduces the full visible spectrum accurately while maintaining the energy efficiency of LED excitation, resolving the contradiction between energy efficiency and color rendering.
3Duration of action of moving object
If conventional light bulbs are used, then initial cost is low, but lifetime is short (750-1000 hours for incandescent)
Solution Approach 1:
The patent designs the LED lighting system as a self-contained module where the LED, phosphors, and encapsulant work together as an integrated unit. This self-service design eliminates the need for separate replacement of bulbs and fixtures, extending the effective lifetime of the entire lighting system while maintaining ease of manufacture through modular assembly.
4Use of energy by moving object
If light emitting diodes are used, then energy efficiency and lifetime improve, but color rendering index (CRI) and white light production are challenging
Solution Approach 1:
The patent introduces phosphors as an intermediary substance between the LED and the viewer. The phosphors absorb the narrow-spectrum light from the LED and re-emit it as broad-spectrum visible light, acting as a mediator that transforms the LED's output into high-CRI white light while preserving the energy efficiency of the original LED excitation.
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 provides lighting devices with high CRI and efficacy, enabling energy-efficient and long-lasting alternatives to traditional lighting, suitable for various applications including those where maintenance is challenging, by utilizing LEDs and luminescent materials to produce white light with enhanced color rendering.
Implementation Method 1
Light emitting diodes are well-known semiconductor devices that convert electrical current into light
Implementation Method 2
A second group of solid state light emitters and a second group of lumiphors can be included in the lighting device. Each of the second group of lumiphors, if excited, would emit light having a dominant wavelength in a range from about 495 nm to about 520 nm
Data Source
AI summary
There is provided a lighting device comprising one or more groups of solid state light emitters and one or more groups hof lumiphors, which emits mixed illumination having x, y color coordinates within a region defined by (0.32, 0.40), (0.36, 0.38), (0.41, 0.455), and (0.36, 0.48). Also, such lighting devices which emit light having x, y color coordinates within other specified regions. Also, such lighting devices with respective groups which emit light within two specified regions, and which mix to produce light within such regions. Also, methods of lighting light from such emitters and/or lumiphors.