LED Chip with Integrated Reverse-Biased Protection Structure
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Solution Overview
Problem
Solid-state lighting devices, such as LEDs, are vulnerable to electrical overstress events like electrostatic discharge, which can cause latent failures leading to catastrophic damage, and existing solutions often require separate protection chips, increasing complexity and cost.
Innovation Solution
Incorporating a separate active LED structure electrically connected in reverse relative to the primary light-emitting structure within the LED chip, allowing reverse current to flow during overstress events and protect the light-emitting structure, eliminating the need for external protection chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate electrical overstress protection chip (such as Zener diode or ESD chip) is included in packaged LED components, then protection against electrical overstress events is provided, but device complexity increases
Solution Approach 1:
The patent merges the electrical overstress protection function with the primary LED structure by integrating a reverse-connected LED structure directly into the same chip. This eliminates the need for separate protection chips while maintaining protection functionality, thereby reducing device complexity while preserving reliability.
Solution Approach 2:
The integrated reverse-connected LED structure serves dual functions: it acts as the primary light-emitting structure during normal operation and simultaneously provides electrical overstress protection during reverse bias conditions. This multi-functionality reduces the need for additional dedicated protection components.
2Reliability
If separate electrical overstress protection chips are used, then protection against electrical overstress events is provided, but manufacturing complexity and cost increase
Solution Approach 1:
By combining the protection structure with the primary LED structure into a single integrated chip, the manufacturing process is simplified. The reverse-connected LED structure is fabricated using the same semiconductor processes as the primary structure, eliminating the need for separate assembly steps and reducing manufacturing complexity.
3Reliability
If the LED structure is electrically connected in reverse for protection, then electrical overstress protection is provided, but forward current flow for light emission may be affected
Solution Approach 1:
The patent segments the LED structure into distinct forward-biased and reverse-biased regions. The reverse-connected protection structure is spatially separated and electrically isolated during forward operation, ensuring that forward current flows exclusively through the light-emitting structure without being diverted to the protection structure, thus maintaining forward current efficiency.
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 built-in electrical overstress protection mechanism enhances the reliability of LEDs by preventing damage from electrical surges without requiring additional components, simplifying manufacturing and reducing costs.
Implementation Method 1
a second active LED structure that comprises a second n-type layer, a second p-type layer, and a second active layer, the second active LED structure is electrically coupled in reverse relative to the first active LED structure
Data Source
AI summary
Solid-state lighting devices including light-emitting diodes (LEDs) and more particularly LED chip structures with electrical overstress protection are disclosed. LED chip structures are disclosed that include built-in electrical overstress protection. An exemplary LED chip may include an active LED structure that is arranged as a primary light-emitting structure and a separate active LED structure that is arranged as an electrical overstress protection structure. The electrical overstress protection structure may be electrically connected in reverse relative to the primary light-emitting structure. In this manner, under normal operating conditions, forward current will flow through the primary light-emitting structure to generate desired light emissions, and during an electrical overstress event, reverse current may flow through the electrical overstress protection structure, thereby protecting the light-emitting structure from damage.