Wavelength Converting Element for LED Luminance
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Solution Overview
Problem
Current semiconductor light emitting devices, such as LEDs, face limitations in achieving high luminance, which is essential for applications like automotive lighting and photography, where concentrated and efficient light emission is required.
Innovation Solution
The implementation of a wavelength converting element with a smaller light extraction surface area over the LED, forcing a majority of the light to exit through this smaller area, thereby increasing both luminance and illuminance, while maintaining the angles of emission unchanged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a wavelength converting element with smaller light extraction surface area is placed over the LED, then luminance and illuminance are enhanced, but the light extraction area is reduced
Solution Approach 1:
The patent applies dimensionality change by placing a wavelength converting element with a smaller top surface area over the LED's larger light extraction surface. This creates a stepped configuration where the converting element extends only partially over the light extraction surface in the horizontal dimension, while adding vertical dimension through its thickness. This allows the light to be converted to different wavelengths while maintaining enhanced luminance through the smaller effective emission area.
Solution Approach 2:
The wavelength converting element serves as an intermediary between the LED light source and the final light output. It absorbs light at one wavelength from the LED and converts it to a different wavelength, mediating the transformation while also serving as a physical structure that defines the reduced light extraction area. This intermediary structure enables both wavelength conversion and luminance enhancement simultaneously.
2Ease of operation
If a wavelength converting element with smaller light extraction surface area is placed over the LED, then beam control is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the light extraction function into two distinct areas: the LED's light extraction surface and the wavelength converting element's smaller top surface. This segmentation allows different portions of the device to perform specialized functions - the LED provides broad light emission while the converting element focuses and converts the light, improving beam control through functional division.
Solution Approach 2:
The wavelength converting element introduces local quality variation by having a smaller top surface area compared to the LED's light extraction surface. This creates zones with different optical properties - the covered area experiences wavelength conversion and focused emission, while the uncovered perimeter allows direct LED light extraction. This local differentiation enhances beam control by creating distinct light output zones.
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 approach enhances luminance and illuminance by reducing the light emitting surface area, allowing for greater beam control and potentially smaller, less expensive optics, while maintaining the fractional change in luminance and illuminance.
Implementation Method 1
a wavelength converting element... The wavelength converting element has a second light extraction surface
Data Source
AI summary
In some embodiments of the invention, a device includes a semiconductor light emitting device having a first light extraction surface, a wavelength converting element, and a second light extraction surface. A majority of light extracted from the semiconductor light emitting device is extracted from the first light extraction surface. The first light extraction surface has a first area. The second light extraction surface is disposed over the first light extraction surface and has a second area. The first area is larger than the second area.