Aircraft Light Phosphor Layering for Aviation White Output
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Solution Overview
Problem
Commercially available LEDs often fail to produce the desired aviation white light output, especially when overmolded with optically dense materials like silicone, due to reduced internal reflection and insufficient wavelength shifting.
Innovation Solution
An aircraft light design incorporating a light emitting semiconductor with a first and second light converting material, arranged over a light transmissive layer, to achieve wavelength shifts that result in a desired white light output, including aviation white, by using Cerium doped Yttrium Aluminium Garnet and/or nitridosilicate based materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If LEDs are overmolded with optically dense material like silicone, then protection and structural integrity are improved, but wavelength shifting is reduced and white light output quality deteriorates
Solution Approach 1:
The patent divides the light converting function into two separate materials: a first light converting material (e.g., yellow phosphor) and a second light converting material (e.g., red phosphor). This segmentation allows each material to perform its wavelength shifting function independently before the light exits the silicone envelope, ensuring adequate wavelength conversion even when the silicone is optically dense.
Solution Approach 2:
The patent introduces a light transmissive layer as an intermediary between the first light converting material and the second light converting material. This layer facilitates efficient light transmission and interaction between the two converting materials, ensuring that the wavelength shifting process occurs effectively before the light reaches the optically dense silicone material.
2Device complexity
If a single light converting material is used, then device complexity is reduced, but the desired aviation white light spectrum cannot be achieved
Solution Approach 1:
The patent segments the wavelength conversion function into two distinct materials with different spectral characteristics. The first light converting material converts blue light to yellow, while the second converts blue or yellow light to red. This segmentation enables precise control over the final white light spectrum to meet aviation chromaticity requirements.
Solution Approach 2:
The patent employs a composite light source structure combining multiple light converting materials with different photoluminescence properties. This composite approach allows the system to achieve a broad spectrum white light output with precise chromaticity control, combining the advantages of different phosphor materials to meet stringent aviation lighting standards.
3Use of energy by moving object
If the light emitting semiconductor emits blue light, then energy efficiency is improved, but the spectrum lacks the warmth required for aviation white light
Solution Approach 1:
The first light converting material acts as an intermediary that converts a portion of the efficient blue light to yellow light, while the second light converting material converts additional blue light to red light. This two-stage conversion process maintains energy efficiency by starting with blue LED excitation while adding the spectral warmth components needed for aviation white light.
Solution Approach 2:
The patent changes the spectral parameters of the blue LED light by introducing two different light converting materials with specific emission characteristics. The first material shifts part of the spectrum to yellow wavelengths, and the second material adds red wavelengths, thereby transforming the cold blue spectrum into a warm white spectrum that meets aviation standards while maintaining LED energy efficiency.
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 combination of light converting materials effectively shifts the spectrum towards longer wavelengths, producing a white light output that meets aviation standards, such as defined by FAR 25.1397, and can further enhance to a warmer white for interior lights.
Implementation Method 1
a light emitting semiconductor for emitting light having an initial light spectrum
Implementation Method 2
The first light converting material is configured such that a first portion of the light, which is emitted by the light emitting semiconductor, is shifted towards longer wavelengths by the first light converting material
Implementation Method 3
The second light converting material is configured such that a second portion of the light, which is emitted by the light emitting semiconductor, is shifted towards longer wavelengths by the second light converting material
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An aircraft light (2) providing a white light output has a light source (4) that comprises a light emitting semiconductor (6) for emitting light (16) having an initial light spectrum; a first light converting material (8), arranged over the light emitting semiconductor (6); and a light transmissive layer (10), covering the first light converting material (8). A first portion of the light (16), which is emitted by the light emitting semiconductor (6), is shifted towards longer wavelengths by the first light converting material (8). The aircraft light (2) further comprises a second light converting material (12), which is arranged over the light transmissive layer (10) of the light source (4) and a lens element (14), which is arranged over the second light converting material (12), with light exiting the lens element (14) forming at least a portion of the white light output of the aircraft light (2). A second portion of the light (16), which is emitted by the light emitting semiconductor (6), is shifted towards longer wavelengths by the second light converting material (12).