LED Air Ring Optical Structure for Yellow Ring Effect
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Solution Overview
Problem
LEDs face challenges in achieving color and brightness consistency due to the yellow ring effect, which affects their uniformity and performance.
Innovation Solution
The implementation of a light-emitting device design that includes a wavelength-converting layer and an optical structure, such as an air ring or reflective element, to direct and reflect light, ensuring uniform light output and eliminating the yellow ring effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional LED structure is used, then the device complexity is low, but the light output uniformity deteriorates due to yellow ring effect
Solution Approach 1:
The LED device is segmented into distinct functional zones: a central wavelength-converting layer and a surrounding optical structure (air ring or reflective element). This segmentation allows different regions to perform different functions - the central area converts wavelength while the outer ring manages light direction and reflection, thereby eliminating the yellow ring effect and improving light output uniformity without requiring complete redesign of the entire device
Solution Approach 2:
An intermediary optical structure (air ring or reflective element) is introduced between the light source and the external environment. This intermediary component mediates the light path by reflecting or directing light rays, preventing the formation of the yellow ring effect while maintaining overall device simplicity. The optical structure acts as a buffer that manages light distribution without requiring complex integration
2Manufacturing precision
If no optical structure is added, then the device complexity remains low, but color consistency deteriorates
Solution Approach 1:
Different regions of the LED device are assigned different optical properties: the central wavelength-converting layer has specific material composition for color conversion, while the surrounding optical structure has reflective or directional properties. This local differentiation ensures that each region contributes to color consistency in its specific zone, with the optical structure preventing yellowish discoloration at the periphery while maintaining overall color uniformity
Solution Approach 2:
The solution moves from a two-dimensional planar LED structure to a three-dimensional configuration by adding a vertical optical structure (air ring or reflective element) above or around the light-emitting plane. This dimensional addition creates new light paths and reflection angles that eliminate color inconsistency without requiring complex lateral modifications to the original LED chip structure
3Manufacturing precision
If a wavelength-converting layer with optical structure is implemented, then brightness consistency improves, but device complexity increases
Solution Approach 1:
The LED device is segmented into distinct functional zones: a central wavelength-converting layer and a surrounding optical structure (air ring or reflective element). This segmentation allows different regions to perform different functions - the central area converts wavelength while the outer ring manages light direction and reflection, thereby eliminating the yellow ring effect and improving light output uniformity without requiring complete redesign of the entire device
Solution Approach 2:
An intermediary optical structure (air ring or reflective element) is introduced between the light source and the external environment. This intermediary component mediates the light path by reflecting or directing light rays, preventing the formation of the yellow ring effect while maintaining overall device simplicity. The optical structure acts as a buffer that manages light distribution without requiring complex integration
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 the uniformity and consistency of light output, making the LEDs perform better in terms of color and brightness, thereby improving their overall performance.
Implementation Method 1
a wavelength-converting layer and an optical structure, such as an air ring or reflective element, to direct and reflect light
Implementation Method 2
an optical structure, such as an air ring or reflective element, to direct and reflect light
Data Source
AI summary
In one embodiment, a light-emitting device having a reflector cup, a light source die, a wavelength-converting layer, an optical structure, and an encapsulant is disclosed. The wavelength-converting layer may be configured to convert a narrow band light emitted from the light source die into a broad band light before the light is directed towards a first direction. The optical element may be an air ring embedded within the encapsulant and may be arranged circumscribing the wavelength-converting layer. In another embodiment, a light-emitting device with extended wavelength-converting layer in place of the air ring is presented.