Optical Element Edge Treatment for Lighting Devices
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Solution Overview
Problem
Conventional lighting devices with lumiphoric materials face issues of heat degradation and total internal reflectivity, leading to reduced light output and non-optimal color perception due to the degradation of binding media and separation of phosphor elements from emitters.
Innovation Solution
Incorporating an optical element with a reflective material proximate to its peripheral edge, arranged non-perpendicular to the element's face, to redirect light towards the lumiphoric material, minimizing total internal reflectivity and light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lumiphoric material is physically separated from electrically activated emitter, then reliability and service life are improved, but light loss through edges and total internal reflection increases
Solution Approach 1:
A transparent adhesive layer with refractive index matching the lumiphoric material is introduced as an intermediary between the optical element and lumiphoric material. This mediator reduces total internal reflection at the interface by eliminating refractive index mismatch, thereby reducing light loss while maintaining the physical separation structure for reliability.
Solution Approach 2:
The refractive index parameter of the adhesive layer is specifically selected to match the lumiphoric material, changing the optical parameters at the interface to minimize total internal reflection and edge light loss while preserving the separated structure benefits.
2Illumination intensity
If high current is applied to electrically activated emitter, then light output intensity is improved, but heat generation increases causing binding medium degradation
Solution Approach 1:
The lumiphoric material is extracted and physically separated from the emitter surface, placed on an optical element instead. This extraction allows the emitter to be driven at high currents for high light output while the heat-generating emitter is thermally decoupled from the lumiphoric material, preventing binding medium degradation.
Solution Approach 2:
The lighting device is segmented into separate functional components: the emitter module and the lumiphoric material module, connected optically but not thermally. This segmentation allows independent optimization of each component, enabling high current operation without thermal damage to the lumiphoric material binding medium.
3Ease of manufacture
If conventional binding media are used to deposit lumiphoric materials on emitter surface, then ease of manufacture is improved, but light transmission characteristics deteriorate due to darkening
Solution Approach 1:
The lumiphoric material is extracted from the emitter surface deposition approach and placed on a separate optical element. This eliminates the need for heat-resistant binding media on the emitter surface, as the lumiphoric material is applied to the optical element where different binding conditions apply, preserving light transmission characteristics.
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
This solution enhances light capture and reduces heat-induced degradation, maintaining optimal light output and color uniformity by ensuring that a higher percentage of emitted light is absorbed and re-emitted by the lumiphoric material.
Implementation Method 1
reducing total internal reflectivity and loss of light
Implementation Method 2
a reflective material is disposed proximate to the at least one peripheral edge
Implementation Method 3
absorb a portion of a first peak wavelength emitted by the emitter and re-emit the light at a second peak wavelength
Implementation Method 4
lumiphoric materials that absorb a portion of a first peak wavelength emitted by the emitter and re-emit the light at a second peak wavelength
Data Source
AI summary
A lighting device includes an electrically activated emitter, a lumiphoric material spatially segregated from the emitter, and an optical element arranged between the emitter and the lumiphoric material and having at least one peripheral edge, wherein a reflective material is disposed proximate to the at least one peripheral edge and/or wherein the at least one peripheral edge is non-perpendicular to a face of the optical element and arranged to reflect light in a direction toward the lumiphoric material. An optical element for use with a lighting device including a lumiphoric material includes a peripheral edge, wherein a reflective material disposed substantially parallel to the peripheral edge and/or wherein the peripheral edge is non-perpendicular to a face of the optical element and arranged to reflect light in a direction toward the lumiphoric material.