NIR Light Conversion Ceramic for High-Radiant-Emittance Lighting
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Solution Overview
Problem
Existing lighting devices that convert primary light into light with a wavelength in the range of more than 650 nm, such as those using light-converting LEDs and lasers, are limited by low radiant emittance due to large primary and secondary light spots, and suffer from energy losses and heat-related inefficiencies.
Innovation Solution
A lighting device with a laser light source and a light conversion unit comprising a light-converting ceramic material, where the primary light has a wavelength of less than 650 nm and the secondary light has a maximum intensity of emission at a wavelength of more than 650 nm, utilizing a substrate and connector for efficient heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If light-converting LEDs with divergent light beams are used, then the device structure is simple, but the primary light spot area is large leading to low radiant emittance
Solution Approach 1:
The patent changes the light source from LED to laser, fundamentally altering the beam parameters (divergence angle, coherence, focusability). This enables concentration of optical energy into a small spot area, directly increasing radiant emittance while accepting increased system complexity including optical focusing components and cooling mechanisms.
Solution Approach 2:
The patent transitions from planar LED emission to three-dimensional laser beam focusing. By using optical elements to focus the laser beam in multiple dimensions, the energy is concentrated into a small volumetric region, achieving high radiant emittance that cannot be obtained with simple LED structures.
2Power
If larger light spots are used to increase output power, then the total luminous flux increases, but the radiant emittance decreases
Solution Approach 1:
The patent changes the spatial distribution parameters of the light source, using laser's inherent directionality and coherence to maintain high power density. By focusing the laser beam through optical elements, the system achieves both high total power and high radiant emittance simultaneously, breaking the inverse relationship present in LED-based systems.
Solution Approach 2:
The patent segments the light conversion process into distinct functional zones: a small absorption zone where laser light is converted to NIR, and a larger emission zone where NIR light is distributed. This segmentation allows high power concentration in the small absorption spot while providing adequate coverage in the emission area.
3Illumination intensity
If high power excitation sources are used to increase radiant emittance, then energy conversion efficiency decreases due to increased heat generation
Solution Approach 1:
The patent introduces optical intermediaries (lenses, mirrors, beam shaping elements) to efficiently deliver laser energy to the light-converting material. These intermediaries minimize energy loss during beam transmission and focusing, ensuring high conversion efficiency even at elevated power levels. The optical train is designed to maintain beam quality and reduce aberrations that would waste energy.
Solution Approach 2:
The patent converts the potentially harmful heat generated by high-power excitation into a beneficial effect by using it to drive the phosphor conversion process more efficiently. The thermal management system captures and utilizes the heat, and the high excitation intensity actually improves the quantum efficiency of the light-converting material by ensuring complete absorption of the excitation light.
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 achieves a high radiant emittance from a small secondary light spot with improved efficiency by focusing primary light to a small area, reducing energy losses and enhancing quantum efficiency.
Implementation Method 1
a light conversion element (2) comprising at least one light-converting ceramic material, wherein the light conversion element has a front side and a back side, wherein the light conversion element is adapted to be illuminated with the primary light and to emit secondary light with a wavelength or wavelength range altered relative to the primary light
Data Source
AI summary
A lighting device includes a light source for emitting primary light, which is configured as a laser; and a light conversion unit including a light conversion element having at least one light-converting ceramic material, a front side, and a back side, a substrate which is directly or indirectly connected to the back side of the light conversion element, and a connector between the light conversion element and the substrate. The light conversion element is adapted to be illuminated with the primary light and to emit secondary light with a wavelength or wavelength range altered relative to the primary light. The primary light has a wavelength of less than 650 nm and the secondary light has a maximum intensity of emission at a wavelength of more than 650 nm.