Cerium-Doped Phosphor for High-Current LED Stability
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Solution Overview
Problem
Europium-doped compounds in optoelectronic components exhibit efficiency dips at high current intensities, leading to color locus instability and brightness loss, which is a challenge for achieving high color rendering index and efficient light emission in flashlights for portable devices.
Innovation Solution
An optoelectronic component using a semiconductor chip with a conversion element comprising a cerium-doped phosphor (La1-xCax)3Si6(N1-yOy)11:Ce3+ that generates white mixed light by converting primary blue radiation into secondary radiation, avoiding the inefficiencies of europium-doped materials and maintaining stability at high currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If europium-doped phosphors are used to achieve high color rendering index (CRI>75), then color rendering is improved, but efficiency dips occur at high current intensities leading to brightness loss and color locus instability
Solution Approach 1:
The patent changes the chemical composition parameters of the phosphor material by substituting lanthanum with calcium in the La3Si6N11:Ce structure, creating a new phosphor compound (La1-xCax)3Si6N11:Ce that maintains high CRI while eliminating efficiency dips at high currents
Solution Approach 2:
The patent creates a composite phosphor material combining multiple elements (La, Ca, Si, N, Ce) in a specific structure, where the composite nature provides both high color rendering and high current stability that single-element phosphors cannot achieve
2Illumination intensity
If high current intensities are applied to achieve sufficient light output for flashlight applications, then brightness is improved, but efficiency dips cause brightness loss and color instability
Solution Approach 1:
The patent modifies the phosphor's chemical composition to be more resistant to current-induced efficiency losses, allowing the component to operate at high current intensities without experiencing the typical brightness loss and maintaining stable color output
3Illumination intensity
If multiple phosphors are used to cover the visible spectrum sufficiently well, then color rendering is improved, but device complexity increases
Solution Approach 1:
The patent designs a single phosphor compound (La1-xCax)3Si6N11:Ce that performs multiple functions simultaneously: it provides broad spectrum coverage for high CRI, maintains high efficiency at various current levels, and ensures color stability, replacing what would traditionally require multiple different phosphor materials
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 a more reddish-shifted color locus at lower color temperatures with reduced brightness loss and increased current density, ensuring efficient and stable light emission suitable for flashlights in portable devices.
Implementation Method 1
The semiconductor chip is operated at high current intensities in continuous operation (flash)
Implementation Method 2
The conversion element is configured to generate secondary radiation from the primary radiation
Data Source
AI summary
The invention relates to an optoelectronic component (100) comprising a semiconductor chip (1) for generating a primary beam in the blue spectral range, a conversion element (4) which is arranged in the beam path of the semiconductor chip (2) and is designed to generate a secondary beam from the primary beam, wherein the conversion element (4) comprises at least one first luminescent material (9) used as a conversion material, the first luminescent material (9) being (La1-xCax)3Si6(N1-yOy)11:Ce3+ with 0≤x≤1 and 0<y≤1, wherein a total beam (G) emerging from the component (100) is white mixed light.