Conversion Element Scattering Layer Color Locus Control
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Solution Overview
Problem
Existing light sources, particularly semiconductor-based ones, face challenges in achieving accurate color locus control and efficient conversion due to fluctuations in the thickness and concentration of conversion layers, leading to reduced conversion efficiency and thermal issues.
Innovation Solution
A conversion element comprising a scattering layer, a reflection layer, and a conversion layer, where the scattering layer transmits and scatters primary radiation to expand its solid angle range, allowing for controlled color locus adjustment and efficient conversion of primary to secondary radiation, with the conversion layer containing ceramic materials like cerium- or europium-doped luminescent substances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thickness of the conversion layer or concentration of converter is increased to improve conversion efficiency, then more primary radiation is converted to secondary radiation, but color locus control deteriorates due to fluctuations in thickness and concentration
Solution Approach 1:
A scattering layer is introduced as an intermediary between the primary radiation source and the conversion layer. This scattering layer diffuses the incident radiation, creating a more uniform distribution of energy across the conversion layer, which stabilizes the conversion process and improves color locus control while maintaining high conversion efficiency.
Solution Approach 2:
The patent modifies the optical parameters of the system by introducing a scattering layer that changes the angular distribution and spatial uniformity of the incident radiation. This parameter change allows the conversion layer to operate more uniformly, reducing sensitivity to thickness and concentration variations.
2Productivity
If the conversion layer is placed close to the semiconductor chip to improve optical coupling, then conversion efficiency increases, but thermal problems worsen due to heat generation in the luminescent substances
Solution Approach 1:
The scattering layer serves as a thermal intermediary that optically couples the semiconductor chip to the conversion layer while providing thermal isolation. This allows efficient optical energy transfer for high conversion efficiency while preventing excessive heat transfer to the luminescent substances, thereby managing thermal issues.
Solution Approach 2:
The system is segmented into distinct functional layers: the semiconductor chip, the scattering layer, and the conversion layer. This segmentation allows independent optimization of optical coupling (through the scattering layer) and thermal management (by spacing the conversion layer away from the heat-generating chip).
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 configuration enhances color locus control and conversion efficiency, reducing thermal issues by decoupling the semiconductor chip and conversion element, enabling the generation of high-quality white light with minimal color fringes and efficient heat dissipation.
Implementation Method 1
A conversion element comprises a scattering layer, a reflection layer, and a conversion layer arranged between the scattering layer and the reflection layer. The scattering layer is designed to transmit a first portion of a primary radiation impinging on it from a side facing away from the conversion layer into the conversion layer, and to scatter a second portion of the primary radiation impinging on it toward that side of the scattering layer which faces away from the conversion layer.
Implementation Method 2
the conversion is usually based on the principle of so-called down-conversion. That is to say that light in the blue spectral range, for example, is absorbed and red-shifted light having a lower frequency with respect thereto is emitted. In other words, high-energy light radiation is converted by the luminescent substance into light radiation of lower energy
Implementation Method 3
A conversion element comprises a scattering layer, a reflection layer, and a conversion layer arranged between the scattering layer and the reflection layer
Implementation Method 4
the thermal problems can be solved by setting a suitable distance between the radiation-generating semiconductor chip and the conversion element, wherein the conversion material is embedded into a matrix having good thermal conductivity (e.g. ceramic)
Data Source
AI summary
A conversion element (10) is specified, comprising a scattering layer (12), a reflection layer (14), and a conversion layer (16) arranged between the scattering layer (12) and the reflection layer (14). The scattering layer (12) is designed to transmit a first portion (20) of a primary radiation (18) impinging on it from a side facing away from the conversion layer (16) into the conversion layer (16), and to scatter a second portion (22) of the primary radiation (18) impinging on it towards that side of the scattering layer (12) which faces away from the conversion layer (16). The conversion layer (16) comprises at least one conversion means (25) which is designed to convert at least part of the first portion of the primary radiation (18) into a second radiation (19) having a higher wavelength different from the primary radiation (18). The reflection layer (14) has a reflective effect at least with regard to the second radiation (19).