LED Module Phosphor Distribution via Grounding
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Solution Overview
Problem
LED modules with high phosphor particle density exhibit inhomogeneous light emission due to the inhomogeneous distribution of phosphor particles within the potting compound, caused by electrical potential differences and photoelectric effects during the manufacturing process.
Innovation Solution
Applying a predetermined potential to the LED chips during the dispensing of the potting compound, such as short-circuiting or grounding, and using methods like darkening the LED chips, arranging them in a magnetic field, or inclining the module to ensure phosphor particles sink linearly and homogeneously, can reduce or prevent the inhomogeneous distribution of phosphor particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a high proportion of phosphor particles is introduced into the potting compound to provide high luminance, then the luminance of the LED module is improved, but the light emission becomes inhomogeneous over the emission angle
Solution Approach 1:
The patent applies a predetermined potential (grounding or short-circuiting) to the LED chip during the dispensing process to eliminate electrical potential differences. This creates an equipotential state that prevents electrostatic forces from deflecting phosphor particles, allowing them to settle uniformly around the LED chip even at high concentrations, thus achieving both high luminance and homogeneous light emission
Solution Approach 2:
The patent changes the electrical parameter (potential) of the LED chip from its normal operating state to a grounded or short-circuited state during the specific process window of phosphor particle settlement. This temporary parameter change eliminates the photoelectric effect and electrostatic deflection, enabling uniform phosphor distribution while maintaining the ability to operate normally afterward
2Reliability
If LED chips are left with electrical potential during the dispensing process, then the normal electrical functionality is maintained, but phosphor particles are deflected leading to inhomogeneous distribution
Solution Approach 1:
The patent applies a preliminary action by grounding or short-circuiting the LED chip before and during the phosphor particle settlement process. This preliminary electrical conditioning prevents the photoelectric effect from occurring during the critical dispensing window, ensuring uniform phosphor distribution. The LED chip's electrical functionality is restored after the phosphor has settled, thus maintaining reliability while achieving manufacturing precision
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 proposed solutions result in a more homogeneous distribution of phosphor particles, leading to a more uniform light emission across the emission angle, improving the overall light output of the LED module.
Implementation Method 1
the LED chips build up an electrical potential and thus an electrical field between the electrodes due to the ambient light and the associated photoelectric effect
Data Source
AI summary
The invention relates to a method for producing an LED module (1) and comprises at least the following steps: - providing at least one LED chip (4) on a substrate material (2), and - dispensing a not-cured (flowable/liquid) potting compound (3) on top of the LED chip (4), said potting compound (3) containing at least one type of luminescent particles and preferably a matrix material. During the step of dispensing, a predetermined potential is applied directly or indirectly to at least one LED chip (4).