LED Halation Elimination via Reflective Layer and Wavelength Conversion
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) with wavelength conversion materials suffer from halation due to incomplete light conversion on lateral surfaces, resulting in unwanted color rings around the LED chip.
Innovation Solution
An LED design featuring a substrate, an LED chip, a wavelength conversion layer covering the top surface, a lens enclosing the chip and conversion layer, and a reflective layer on the lens to reflect unconverted light from the lateral surface, preventing it from escaping and thus eliminating halation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wavelength conversion material is coated only on the top surface of the LED chip, then the coating process is simple, but light emitted from the lateral surface cannot be converted, causing halation with different colors
Solution Approach 1:
The patent introduces a reflective layer as an intermediary component between the LED chip lateral surface and the external environment. This reflective layer captures unconverted light from the lateral surface and redirects it toward the wavelength conversion material on the top surface, preventing direct emission of unconverted light that causes halation. The reflective layer acts as a mediator that transforms the harmful lateral light emission into a useful path for wavelength conversion.
2Object-generated harmful factors
If wavelength conversion material is coated on the lateral surface of the LED chip, then halation is eliminated, but the coating process becomes complex and coating uniformity is difficult to control
Solution Approach 1:
The patent divides the light conversion function into two separate segments: the top surface of the LED chip for wavelength conversion material coating, and the lateral surface for reflective layer application. This segmentation allows each surface to be treated with appropriate coating techniques optimized for its specific requirements, avoiding the complexity of coating the lateral surface directly with wavelength conversion material while still achieving complete light conversion.
3Loss of energy
If wavelength conversion material is coated on the lateral surface, then light conversion is complete, but coating uniformity is poor and production yield decreases
Solution Approach 1:
Instead of coating the wavelength conversion material on the lateral surface (conventional approach), the patent inverts the approach by coating the reflective layer on the lateral surface and keeping the wavelength conversion material on the top surface. This inversion maintains complete light conversion while avoiding the coating uniformity problems associated with lateral surface coating, thereby improving production yield.
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 effectively eliminates halation by ensuring all emitted light is either converted or reflected, maintaining consistent color temperature across the emission angle and preventing unwanted color patterns around the LED.
Implementation Method 1
the surface of the LED chip is covered by a wavelength conversion material for converting the wavelength of the light emitted by the LED chip
Implementation Method 2
The reflective layer is disposed on the lens for reflecting a light emitted from the lateral surface of the LED chip
Data Source
AI summary
A Light emitting diode (LED) includes a substrate, a LED chip, a wavelength conversion layer, a lens and a reflective layer. The LED chip is mounted on the substrate. The wavelength conversion layer covers the top surface of the LED chip and exposes the lateral surface of the LED chip. The lens is disposed on the substrate and encloses the LED chip and the wavelength conversion layer. The reflective layer is disposed on the lens for reflecting the light emitted from the lateral surface of the LED chip.