LED Current-Guiding Structure with Transient Protection
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Solution Overview
Problem
Conventional current-guiding structures in LED devices limit thermal conductivity, making them prone to increased operating temperatures and reduced reliability, and are susceptible to damage from electrostatic discharge and high voltage transients.
Innovation Solution
The implementation of a current-guiding structure with high and low contact resistance areas and a second current path, including a protective device, to control current flow and provide transient voltage suppression, enhancing thermal conductivity and protecting against electrostatic discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional current-blocking structures (insulative layer or air cavity) are used to guide current, then current control is achieved, but thermal conductivity is limited and operating temperature increases
Solution Approach 1:
The patent applies local quality by creating distinct high resistance and low resistance contact areas within the reflective layer. The high resistance areas block current laterally while the low resistance areas provide thermal conduction paths, allowing current guidance without compromising overall thermal conductivity. This localized differentiation resolves the contradiction by enabling current control in specific regions while maintaining heat dissipation in other regions.
Solution Approach 2:
The reflective layer is segmented into multiple functional zones: high resistance contact areas for current blocking, low resistance contact areas for thermal conduction, and fully conductive areas. This segmentation allows the structure to simultaneously perform current guidance and heat dissipation functions, resolving the contradiction between current control and thermal management.
2Reliability
If conventional current-blocking structures are used, then current flow is controlled, but device susceptibility to electrostatic discharge and high voltage transients increases
Solution Approach 1:
The patent implements preliminary action by incorporating a transient voltage suppression device and protective structure before harmful electrostatic discharge or high voltage transients can damage the LED. These protective elements are pre-positioned to intercept and dissipate voltage spikes before they reach sensitive semiconductor layers, thereby preventing damage and improving reliability.
Solution Approach 2:
The protective structure acts as a cushioning element that absorbs and dissipates the energy of electrostatic discharge and voltage transients before they can harm the LED. The second current path provides an alternative route for surge current, cushioning the main LED structure from harmful electrical events.
3Object-affected harmful factors
If a second current path with protective device is added, then protection against transients is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the reflective layer to serve multiple functions simultaneously: it reflects light, provides current guidance through resistance differentiation, conducts heat through low resistance areas, and interfaces with transient protection devices. This multi-functionality reduces the need for separate dedicated structures, thereby limiting the increase in complexity while achieving comprehensive protection.
Solution Approach 2:
The protective structure is merged with the existing reflective layer and substrate assembly rather than being added as a completely separate component. The second current path is integrated into the overall device architecture, combining protection functionality with existing structural elements to minimize complexity increase.
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 results in improved thermal conductivity, increased reliability, and enhanced protection against electrostatic discharge, leading to longer device lifetime and reduced susceptibility to damage from high voltage transients.
Implementation Method 1
an electrically conductive material coupled between the substrate and the n-type semiconductor layer and forming a non-ohmic contact with the n-type semiconductor layer
Implementation Method 2
a protective device disposed above the n-type semiconductor; and an electrically conductive material coupled between the substrate and the protective device
Data Source
AI summary
Methods for controlling current flow in semiconductor devices, such as LEDs are provided. For some embodiments, a current-guiding structure may be provided including adjacent high and low contact areas. For some embodiments, a second current path (in addition to a current path between an n-contact pad and a substrate) may be provided. For some embodiments, both a current-guiding structure and second current path may be provided.