Phosphor LED Signal Lighting with Chromaticity Control
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Solution Overview
Problem
Current automotive and marine LED lighting technologies face challenges in producing amber and red light that meets regulatory requirements due to issues like color shifting and intensity loss, limiting the use of white LEDs in vehicle applications.
Innovation Solution
A solid state white light illumination device using a limited number of white LEDs with a lens to manipulate chromaticity and color temperature, combined with a clear or colored filter to achieve desired spectral characteristics, ensuring compliance with vehicle lighting standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If amber AlInGaP LED technology is used to generate light output, then the device directly produces light in the desired color spectrum, but heat generation during operation causes color shifting and intensity loss that prevents meeting government standards
Solution Approach 1:
The patent introduces a phosphor material as an intermediary between the blue LED and the final amber light output. The phosphor converts excess blue light into yellow-green wavelengths, which combine with remaining blue light to produce amber output. This mediator approach allows the system to achieve stable color output without the heat-related color shifting problems of direct amber LEDs.
Solution Approach 2:
The patent adjusts the phosphor composition and particle characteristics to optimize the conversion of blue light to amber output. By controlling phosphor parameters such as material composition, particle size, and concentration, the system achieves consistent color temperature and chromaticity coordinates that meet regulatory standards while maintaining manufacturing efficiency.
2Use of energy by moving object
If white LEDs with phosphor are used to convert blue light to white light, then the device achieves efficient light generation, but the output spectrum is ill-suited for applications requiring specific chromaticity coordinates
Solution Approach 1:
The patent applies local quality by using different phosphor materials in different regions or layers within the LED assembly. This allows selective conversion of blue light to specific wavelengths, creating a tailored spectrum that maintains high efficiency while achieving the precise chromaticity coordinates required for amber or red signal lighting applications.
3Illumination intensity
If colored plastic lenses are used over white light bulbs to produce desired chromaticity, then visibility and illumination characteristics are maximized, but the choice of lens materials is limited by regulatory approvals and the process is costly and time-intensive
Solution Approach 1:
The patent extracts the color filtering function from separate colored plastic lenses and integrates it directly into the LED light source through phosphor conversion. This eliminates the need for separate lens materials requiring regulatory approval, as the amber or red output is generated directly by the LED-phosphor assembly, simplifying the material approval process while maintaining visibility requirements.
4Stability of the object's composition
If InGaN die and phosphor combinations are used to convert short wavelength blue or ultraviolet light to longer wavelengths, then color shift during warm-up is reduced, but the cost of customized development substantially increases
Solution Approach 1:
The patent uses a universal blue LED die combined with phosphor materials that serve multiple functions: converting excess blue light to yellow-green wavelengths, establishing the amber color output, and providing thermal management benefits. This multi-functional approach achieves color stability during warm-up using standardized blue LED dies and off-the-shelf phosphor materials, avoiding the high costs of customized InGaN die development.
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 a cost-effective, compact, and bright LED-based vehicle light with reduced warm-up induced color shift and intensity loss, meeting regulatory requirements for automotive, marine, and aviation applications.
Implementation Method 1
A lens is disposed over the white light LED that manipulates at least one of a chromaticity, a color temperature value, and a color rendering index value associated with light emitted beyond the illumination device
Implementation Method 2
combined with a clear or colored filter to achieve desired spectral characteristics
Data Source
AI summary
An illumination device and methods of forming illumination devices having a limited number of white light light emitting diodes (LED's) or solid state lighting (SSL) devices and a color filtering lens or light manipulator disposed over the white light LED to manipulate at least one of a chromaticity, a color temperature value, and a color rendering index (CRI) value of light emitted beyond the illumination device to satisfy regulatory visibly and/or illumination requirements with a more efficiently operable illumination device.