Reflective LED Die Contacts for Higher Light Output
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Solution Overview
Problem
Conventional solid state transducer (SST) dies suffer from reduced light output due to absorption of reflected light by electrical contacts, which also creates undesirable dark areas on the surface of the SST die.
Innovation Solution
The implementation of a reflective material over, covering, or proximate to selected electrical contacts on SST dies to reflect returned light away from the contacts, thereby reducing absorption and enhancing light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If electrical contacts are placed on the SST die surface to conduct electricity, then electrical connectivity is achieved, but light output is reduced due to absorption by the contacts
Solution Approach 1:
The patent applies the principle of converting harm into benefit by transforming the harmful light-absorbing contacts into beneficial light-reflecting structures. Metallic reflective layers are deposited over the electrical contacts, converting them from light-absorbing elements into light-reflecting elements that redirect emitted light outward through the sapphire substrate, thereby increasing overall light output while maintaining electrical functionality.
Solution Approach 2:
The patent utilizes optical property changes by depositing metallic reflective layers with specific reflectivity characteristics over the electrical contacts. These layers alter the optical interaction of the contacts with emitted light, changing them from absorptive to reflective surfaces that enhance light extraction efficiency.
2Illumination intensity
If electrical contacts are placed on the SST die surface, then electrical connectivity is achieved, but dark areas appear on the die surface
Solution Approach 1:
The patent converts the harmful visual effect of dark contact areas into a beneficial feature by coating the contacts with metallic reflective layers. These layers reflect emitted light away from the contact regions, preventing the formation of dark areas and instead creating bright, reflective regions that enhance the overall visual appearance of the die.
3Illumination intensity
If reflective material is added over electrical contacts to increase light output, then light absorption by contacts is reduced, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the electrical contact structure by integrating the electrical conductivity function with the light reflection function. The metallic reflective layers are deposited directly over the electrical contacts, combining electrical conduction and optical reflection into a single integrated structure, thereby minimizing additional complexity while maximizing light output.
Solution Approach 2:
The electrical contact structure is designed to serve multiple functions simultaneously: electrical conduction, light reflection, and visual appearance enhancement. The metallic layers perform both electrical and optical functions, making the contact structure universal and multi-functional rather than requiring separate components for each function.
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 solution increases the efficiency and improves the visual appearance of SST dies by minimizing light absorption by electrical contacts and enhancing the overall light output.
Implementation Method 1
The implementation of a reflective material over, covering, or proximate to selected electrical contacts on SST dies to reflect returned light away from the contacts
Data Source
AI summary
Systems and methods for improved light emitting efficiency of a solid state transducer (SST), for example light emitting diodes (LED), are disclosed. One embodiment of an SST die in accordance with the technology includes a reflective material disposed over electrical connectors on a front side of the die. The reflective material has a higher reflectivity than a base material of the connectors such that light traveling toward the connectors reflects back out of the device.