Solid State Lighting with Remote Phosphors for Black Body Spectrum
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Solution Overview
Problem
Current solid state lighting technologies, such as LED-based systems, often produce light with undesirable spectral characteristics, leading to unnatural color representation of objects under illumination, particularly at specific color temperatures, due to peaks, valleys, or gaps in the output spectrum.
Innovation Solution
A light emitting device comprising a solid state source and multiple phosphors, where the phosphors are excited by the solid state source's electromagnetic energy to produce a visible light output that approximates a black body radiation spectrum for a given color temperature, using a remote phosphor deployment configuration to achieve consistent and natural color representation across a broad range of the visible spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LED pumped phosphors are used to generate white light, then energy efficiency is improved, but spectral characteristic becomes undesirable with peaks and valleys in the visible light range
Solution Approach 1:
The patent segments the white light generation process by using multiple separate phosphor materials (including red, green, and blue phosphors) that are individually excited by a UV or blue LED source. Each phosphor emits light in a specific wavelength range, and by combining these segmented spectral components, the patent achieves a more complete and natural black-body-like spectrum without the peaks and valleys characteristic of traditional single-phosphor approaches.
2Manufacturing precision
If remote phosphor deployment is used, then color characteristic repeatability is improved, but device complexity increases
Solution Approach 1:
The patent introduces a remote phosphor deployment configuration where phosphor materials are positioned at a distance from the LED source, separated by an optical medium (such as a transparent housing or air gap). This intermediary arrangement allows the phosphors to be excited by the LED light while enabling more consistent and repeatable color characteristics, as the remote positioning reduces sensitivity to manufacturing variations in phosphor placement and LED-to-phosphor alignment.
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 high-quality spectral content with a color temperature corresponding to a rated temperature, ensuring natural illumination and meeting industry standards, with a consistent repeatable light output that deviates no more than ±50% from the black body radiation spectrum over 210 nm of the visible spectrum, achieving a high CRI of 85 or higher.
Implementation Method 1
phosphors positioned to receive electromagnetic energy from the solid state source. Each of the phosphors is of a type excited in response to electromagnetic energy of the first emission spectrum from the solid state source for re-emitting visible light of a different one of a corresponding number of second emission spectra
Data Source
AI summary
Solid state light emitting devices and/or solid state lighting devices use three or more phosphors excited by energy from a solid state source. The phosphors are selected and included in proportions such that the visible light output of such a device exhibits a radiation spectrum that approximates a black body radiation spectrum for the rated color temperature for the device, over at least a predetermined portion of the visible light spectrum.