Flat Wavelength Converter Layout for Small LED Source Size
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Solution Overview
Problem
Conventional wavelength converted semiconductor light emitting devices have a large source size due to the extension of phosphor layers over the edges of light emitting diodes, leading to reduced brightness and undesirable characteristics in certain applications.
Innovation Solution
A semiconductor light emitting device with a flat wavelength converting element attached, featuring a wavelength converting layer on a transparent layer, and a reflective material on the sides, which is designed to absorb and emit light of a different wavelength, while maintaining a small source size by precise dicing and handling techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If phosphor layers are extended over the edges of light emitting diodes to ensure complete wavelength conversion, then wavelength conversion efficiency is improved, but source size increases leading to reduced brightness
Solution Approach 1:
The device is divided into distinct functional zones: a central active region with phosphor layers for wavelength conversion, and side regions with reflective materials to redirect light. This segmentation allows the phosphor to be concentrated where needed while using reflection to compensate for edges, thereby maintaining conversion efficiency without expanding the effective source area.
Solution Approach 2:
Reflective materials are introduced as intermediary elements on the sides of the light emitting diode. These materials act as mediators to redirect light that would otherwise be lost at the edges, effectively increasing the utilization of the phosphor layer without requiring the phosphor to extend beyond the LED edges, thus maintaining a compact source size.
2Loss of energy
If phosphor layers are extended over the edges of light emitting diodes, then wavelength conversion coverage is improved, but brightness is reduced due to larger source size
Solution Approach 1:
Different regions of the device are assigned different functional qualities: the central region contains phosphor layers optimized for wavelength conversion, while the side regions contain reflective materials optimized for light redirection. This local differentiation ensures that each zone performs its specific function efficiently, maintaining high brightness from the central region while achieving complete wavelength conversion through the combined action of all regions.
Solution Approach 2:
The light that would naturally be lost at the edges (a harmful factor reducing overall efficiency) is converted into a beneficial resource by introducing reflective materials that redirect this edge light back into the optical path. This transforms the previously wasted edge light into useful illumination, maintaining brightness while ensuring complete wavelength conversion coverage.
3Illumination intensity
If precise dicing and handling techniques are used to maintain small source size, then brightness is improved, but device complexity increases
Solution Approach 1:
The phosphor layers and reflective materials are integrated into a single unified structure that is manufactured as one component. This merging eliminates the need for separate assembly steps and precise alignment procedures, reducing manufacturing complexity while maintaining the small source size design that delivers high brightness.
Solution Approach 2:
The side regions serve multiple functions: they provide structural support, act as light-trapping elements, and function as reflective surfaces. This multi-functionality reduces the number of separate components needed, simplifying the overall device structure and manufacturing process while maintaining the brightness benefits of the compact design.
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 results in a compact lighting structure with improved brightness and efficiency by minimizing the source size, making it suitable for various applications while being cost-effective to manufacture.
Implementation Method 1
a wavelength converting layer for absorbing light emitted by the semiconductor light emitting device and emitting light of a different wavelength
Implementation Method 2
a reflective material disposed on the sides of the semiconductor light emitting device
Data Source
Figure 1A~1D
Figure 2~4
Figure 5~8
AI summary
A lighting structure according to embodiments of the invention includes a semiconductor light emitting device and a flat wavelength converting element attached to the semiconductor light emitting device. The flat wavelength converting element includes a wavelength converting layer for absorbing light emitted by the semiconductor light emitting device and emitting light of a different wavelength. The flat wavelength converting element further includes a transparent layer. The wavelength converting layer is formed on the transparent layer.