Multi-Layer Wavelength Conversion for Higher LED Light Extraction
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Solution Overview
Problem
Existing light-emitting devices with wavelength conversion materials bonded to LEDs face challenges in enhancing luminous efficiency, particularly in achieving efficient light extraction and minimizing light scattering.
Innovation Solution
The light-emitting device incorporates a light-emitting element, a first wavelength conversion member, a second wavelength conversion member, and a first light-reflective member. The wavelength conversion members absorb and convert the light emitted by the LED, while the light-reflective member enhances light extraction by reflecting and scattering the light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a wavelength conversion material is bonded with a light-emitting diode (LED), then light conversion is achieved, but light scattering increases and luminous efficiency decreases
Solution Approach 1:
The patent divides the wavelength conversion structure into multiple segments: a first wavelength conversion layer containing red phosphors, a second wavelength conversion layer containing yellow phosphors, and a third wavelength conversion layer containing green phosphors. Each layer is positioned at different heights above the LED chip, creating a stepped configuration. This segmentation reduces light scattering by separating the conversion functions and allowing controlled light extraction at each stage, thereby improving overall luminous efficiency.
Solution Approach 2:
The patent transitions from a conventional planar wavelength conversion layer to a three-dimensional stepped structure with multiple layers at different heights. The first wavelength conversion layer is positioned at a first height, the second at a second height, and the third at a third height, creating vertical dimensionality. This dimensional change allows light to be converted and extracted at multiple levels, reducing scattering losses and improving luminous efficiency.
2Productivity
If multiple wavelength conversion layers are stacked, then light conversion efficiency improves, but device complexity increases
Solution Approach 1:
The patent combines multiple wavelength conversion functions into a single integrated stepped structure. The first, second, and third wavelength conversion layers are formed in a unified configuration where each layer serves dual purposes: converting specific wavelengths and providing light extraction surfaces. This merging approach achieves high light conversion efficiency while avoiding the complexity of separate stacked converters, as the layers are positioned and configured to work together in a coordinated manner.
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 significantly improves the luminous efficiency of the light-emitting device by optimizing light conversion and extraction, reducing light scattering, and enhancing the reliability of the device, especially in high-temperature high-humidity environments.
Implementation Method 1
The first wavelength conversion member includes a wavelength conversion material that absorbs at least a portion of the first light and emits a second light. The second light has a second peak wavelength different from the first peak wavelength.
Implementation Method 2
The wavelength conversion material that absorbs at least a portion of the first light and emits a second light
Implementation Method 3
The first light-reflective member is located on the second wavelength conversion member. The first light-reflective member is located at least on the light-emitting element.
Implementation Method 4
the light-reflective member enhances light extraction by reflecting and scattering the light
Data Source
AI summary
A light-emitting device includes: a light-emitting element emitting a first light having a first peak wavelength; a first wavelength conversion member contacting a side surface of the light-emitting element and including a wavelength conversion material absorbing at least a portion of the first light and emitting a second light having a second peak wavelength different from the first peak wavelength; a second wavelength conversion member on the first wavelength conversion member, the second wavelength conversion member including a wavelength conversion material absorbing at least a portion of the first light and emitting a third light having a third peak wavelength different from the first and second peak wavelengths; and a first light-reflective member on the second wavelength conversion member and at least on the light-emitting element. A continuous light-emitting surface includes a side surface of the first wavelength conversion member and a side surface of the second wavelength conversion member.