Wavelength Converted LED Light Curable Coating Ring-Effect
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Solution Overview
Problem
Wavelength converted light emitting diodes (LEDs) suffer from a 'ring-effect' where unconverted light leaks out, especially at the edges of the wavelength converting material, leading to reduced conversion efficiency and the need for absorptive filters to remove unconverted light.
Innovation Solution
A light curable coating material is applied on the outer surface of the LED, which cures upon illumination by unconverted light to form a scattering, absorbing, or reflective material, preventing leakage and increasing conversion efficiency by reflecting unconverted light back into the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a self-supporting wavelength converting body is used with transmissive bonding material, then the device structure is simplified and manufacturing is easier, but unconverted light leaks through the lateral surfaces of the bonding material creating a ring-effect
Solution Approach 1:
The patent applies a light curable coating material to the lateral surfaces of the bonding material. This coating is initially transmissive to allow easy application, then cured by illuminating with unconverted light to form a light blocking barrier. The harmful unconverted light that would create the ring-effect is now blocked, converting the previously harmful lateral surface into a beneficial light-blocking structure.
Solution Approach 2:
The light curable coating material is applied in advance to the lateral surfaces of the bonding material before the device operates. When cured by unconverted light, it creates a preventive barrier that stops unconverted light from leaking laterally. This preliminary action prevents the ring-effect before it can occur during device operation.
2Object-generated harmful factors
If absorptive filters are added to remove unconverted light, then the ring-effect is eliminated, but the device complexity increases
Solution Approach 1:
The light curable coating material serves multiple functions: it acts as a light blocking barrier to prevent the ring-effect, and simultaneously utilizes the unconverted light for its own curing process. This multi-functionality eliminates the need for separate absorptive filters, maintaining device simplicity while achieving the desired light management.
Solution Approach 2:
The unconverted light that would normally be harmful and require external filters is instead utilized to cure the coating material itself. The device uses its own unconverted light to activate the coating, which then blocks the ring-effect. This self-service approach eliminates the need for additional filter components.
3Productivity
If the wavelength converting material is placed close to the LED chip, then conversion efficiency is improved, but heat management becomes more difficult
Solution Approach 1:
The patent introduces a bonding material layer that separates the LED chip from the wavelength converting body. This segmentation allows the converting material to be positioned close to the chip for high conversion efficiency while the bonding layer acts as a thermal management interface, potentially incorporating heat dissipation features or materials to manage the thermal load.
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 method significantly reduces unconverted light leakage, enhancing light utilization efficiency by ensuring that unconverted light is either absorbed or reflected back for further conversion, thereby minimizing the 'ring-effect' and improving overall light conversion within the device.
Implementation Method 1
a light curable coating material is applied on regions of a wavelength converted light emitting diode where unconverted light is prone to exit the device, to prevent leakage of unconverted light. The coating material is cured by illuminating the coating material with unconverted light emitted by the light emitting diode
Implementation Method 2
By applicatio of wavelength converting materials, such a fluorescent and/or luminescent materials, in the path of light, the emitted wavelength can be adapted to many specific wavelengths
Implementation Method 3
By applicatio of wavelength converting materials, such a fluorescent and/or luminescent materials, in the path of light, the emitted wavelength can be adapted to many specific wavelengths
Implementation Method 4
The coating material is cured by illuminating the coating material with unconverted light emitted by the light emitting diode to form a cured material that scatters, absorbs or reflects light
Implementation Method 5
The coating material is cured by illuminating the coating material with unconverted light emitted by the light emitting diode to form a cured material that scatters, absorbs or reflects light
Data Source
Figure 1
Figure 2a~2d
AI summary
A method for the manufacture of a wavelength converted light emitting device is provided. A light curable coating material is arranged on the outer surface of a wavelength converted light emitting diode. The light curable coating material is cured, in positions where a high intensity of unconverted LED-light encounters the curable coating material. The method can be used to selectively stop unconverted light from exiting the device, leading to a wavelength converted LED essentially only emitting converted light.