LED Lighting Apparatus Localized Phosphor Coating
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Solution Overview
Problem
Conventional LED lighting instruments often exhibit a non-white appearance when turned off, which is aesthetically undesirable due to the use of bulk phosphor materials that can impart a yellowish tone.
Innovation Solution
A lighting apparatus with semiconductor photonic dies coated in a localized phosphor film, where each die has a respective phosphor coating and is spaced apart from others, reducing the overall amount of phosphor particles and minimizing their influence, resulting in a substantially white appearance when the device is off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If bulk phosphor materials are used in conventional LED lighting instruments, then the LED can emit light with desired color temperature when turned on, but the LED exhibits a yellowish appearance when turned off
Solution Approach 1:
The patent divides the phosphor application into individual localized coatings on each light-emitting die rather than using bulk phosphor materials. Each die receives its own phosphor coating in the spacing between adjacent dies, which reduces the overall phosphor particle density and eliminates the yellowish appearance when off while maintaining color temperature when on
Solution Approach 2:
The patent applies phosphor coating locally to specific regions - specifically in the spacing between adjacent light-emitting dies - rather than uniformly throughout the entire LED structure. This localized application allows precise control over phosphor distribution, maintaining illumination quality while improving aesthetic appearance when off
2Illumination intensity
If phosphor particles are used to convert light wavelength, then the LED can achieve desired color output, but the phosphor particles impart a yellowish tone when the LED is turned off
Solution Approach 1:
The patent extracts phosphor particles from the conventional bulk configuration and relocates them to localized positions between individual dies. This extraction from bulk form reduces the concentration of phosphor particles visible when off, eliminating the yellowish tone while preserving their light-converting function when the LED is active
Solution Approach 2:
The patent changes the distribution parameter of phosphor particles from bulk/concentrated to localized/dispersed. By controlling the spatial distribution and reducing phosphor particle density in visible areas, the patent maintains color output functionality while eliminating the harmful yellowish appearance when off
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 localized phosphor coating scheme allows the LED lighting instrument to maintain a white appearance when turned off, enhancing aesthetic appeal by reducing the yellowish tone typically associated with conventional LED lighting.
Implementation Method 1
each light-emitting die is covered with a respective individual phosphor coating
Data Source
AI summary
A lighting apparatus includes a substrate, a plurality of light-emitting dies disposed on the substrate and spaced apart from one another, a continuous structure disposed over the substrate and covering the light-emitting dies within, and a filler. The light-emitting dies each are covered with an individual phosphor coating and the filler is between the continuous structure and the phosphor coating for each of the light-emitting dies. The lighting apparatus has a substantially white appearance when the plurality of light-emitting dies is turned off.