Lighting Device Filter Lumiphor Back-Scattering
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Solution Overview
Problem
Conventional lighting devices using solid state light emitters suffer from energy loss due to back-scattering of excitation light and self-absorption of luminescent materials, leading to reduced efficiency and performance, particularly in achieving desirable color rendering indices and longevity.
Innovation Solution
A lighting device comprising a solid state light emitter, a filter, and a lumiphor, where the filter allows most of the emitter's light to pass through and reflects back-scattered lumiphor light, optimizing light extraction and absorption to produce a mixture of light with improved color coordinates on the CIE Chromaticity Diagram, thereby enhancing energy efficiency and color rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a lumiphor is used to convert light from a solid state light emitter, then color rendering is improved, but energy loss occurs due to back-scattering of excitation light and self-absorption of luminescent materials
Solution Approach 1:
The lighting device is divided into distinct functional components: a solid state light emitter (first light source), a filter, and a lumiphor (second light source). This segmentation allows each component to perform its specific function optimally - the emitter provides excitation light, the filter selectively transmits and reflects wavelengths, and the lumiphor converts specific wavelengths to improve color rendering, thereby reducing energy loss from back-scattering and self-absorption.
Solution Approach 2:
A filter is introduced as an intermediary component between the solid state light emitter and the lumiphor. This filter acts as a mediator that selectively transmits excitation light to the lumiphor while reflecting back-scattered luminescent light away from the emitter, preventing energy loss and improving overall system efficiency while maintaining enhanced color rendering.
2Illumination intensity
If the lumiphor absorbs more excitation light to improve color coordinates, then color rendering index improves, but light extraction efficiency decreases due to self-absorption
Solution Approach 1:
The filter provides localized wavelength-selective properties at different positions and directions. It selectively transmits excitation light wavelengths to the lumiphor while reflecting luminescent light wavelengths back away from the emitter. This local quality control ensures that the lumiphor receives sufficient excitation light for improved color coordinates while preventing self-absorption losses that would reduce light extraction efficiency.
3Duration of action of stationary object
If conventional lighting devices are used to achieve long service life, then device longevity is improved, but energy efficiency deteriorates
Solution Approach 1:
The invention changes key operational parameters by using solid state light emitters instead of conventional lighting sources. Solid state emitters have significantly longer lifetimes (50,000-70,000 hours vs. 750-1,000 hours for incandescent bulbs) and much higher energy efficiency, converting electrical energy directly to light with minimal heat loss. The addition of the filter-lumiphor system further optimizes energy utilization by reducing back-scattering losses.
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 significantly reduces energy loss, improves light extraction, and achieves color coordinates closer to the blackbody locus, resulting in more efficient and effective lighting with enhanced color rendering and longer device lifespan.
Implementation Method 1
Light emitting diodes are semiconducting devices that emit light (ultraviolet, visible, or infrared) when a potential difference is applied across a p-n junction structure
Implementation Method 2
a luminescent material (e.g., a phosphor) that emits yellow light in response to excitation by light emitted by the light emitting diode
Implementation Method 3
the first light filter allows passage of at least some light having wavelength within a first solid state emitter range of wavelength and reflects at least some light having wavelength outside the first solid state emitter range of wavelength
Data Source
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AI summary
A lighting device (10), comprising a solid state light emitter (11) and a light filter (12). At least a portion of light emitted by the light emitter (11) contacts the filter (12), and at least part of the light passes through the filter (12). Also, such lighting devices further comprising luminophoric material (13), in which at least some of the first part of the light is absorbed by the luminophoric material (13), which then emits light, and at least a portion of any light emitted by the luminophoric material (13) directed toward the filter (12) is reflected by the filter (12). Also, a method of lighting, comprising illuminating a solid state light emitter (11) in such devices. Also, a lighting device, comprising a solid state light emitter (11); a luminophoric material (13) and filter (12) means for allowing at least a portion of light emitted by the light emitter (11) to pass through and for reflecting a second portion of light emitted by the luminophoric material (13) after the luminophoric material (13) is excited.