Semiconductor Light Emitting Element Common Pad Design
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Solution Overview
Problem
Semiconductor light emitting devices with stacked LEDs have low light extraction efficiency due to numerous light-shielding interconnects, leading to reduced luminous efficiency and complex assembly processes.
Innovation Solution
A semiconductor light emitting element design featuring a light-transmissive conductive layer and reduced interconnects, with a common pad for both light emitting units, and a transparent bonding member between LED chips, allowing for independent current injection and simplified assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple LEDs are stacked with many light-shielding interconnects, then electrical connection between light emitting units is improved, but light extraction efficiency deteriorates
Solution Approach 1:
The patent extracts and removes light-shielding interconnects from the optical path between stacked LEDs. Specifically, the invention eliminates the need for interconnects in the light extraction region by using a common pad structure, thereby removing the harmful light-shielding elements while maintaining electrical connectivity through alternative pathways.
Solution Approach 2:
The patent merges the pad structures of multiple light emitting units into a single common pad. This consolidation reduces the total number of interconnects required and creates a shared electrical connection point that does not obstruct light extraction, thereby combining multiple functions into a unified structure.
2Reliability
If many interconnects are provided for electrical connection, then electrical connectivity is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple separate pad structures into a single common pad that serves multiple light emitting units. This consolidation significantly reduces the number of interconnects required and simplifies the overall electrical connection architecture while maintaining full connectivity between all LED units.
Solution Approach 2:
The common pad structure serves multiple functions simultaneously: it provides electrical connection to multiple light emitting units, acts as a light extraction surface, and eliminates the need for separate interconnect structures. This multi-functionality reduces device complexity while maintaining electrical connectivity.
3Reliability
If light-shielding interconnects are used for electrical connection, then electrical connectivity is improved, but luminous efficiency deteriorates
Solution Approach 1:
The patent extracts light-shielding interconnects from the optical path and removes them entirely from the light extraction region. The common pad structure is designed to provide electrical connectivity without introducing light-shielding materials into the optical path, thereby eliminating the harmful effect on luminous efficiency.
Solution Approach 2:
The patent converts the potentially harmful light-shielding effect of interconnects into a beneficial structure by designing the common pad to be transparent or low-absorption to light. The electrical connection function is maintained while the light extraction function is enhanced, turning a harmful element into a beneficial one.
Data Source
AI summary
According to one embodiment, a semiconductor light emitting element includes a first electrode, first and second light emitting units, first and second conductive layers, a first connection electrode, a first dielectric layer, first and second pads, and a first inter-light emitting unit dielectric layer. The first light emitting unit includes first and second semiconductor layers, and a first light emitting layer. The first semiconductor layer includes a first semiconductor portion and a second semiconductor portion. The second light emitting unit includes a third semiconductor layer, a fourth semiconductor layer, and a second light emitting layer. The fourth semiconductor layer is electrically connected with the first electrode. The first conductive layer is electrically connected with the third semiconductor layer. The second conductive layer is electrically connected with the second semiconductor layer. The first connection electrode electrically connects the first conductive layer and the first semiconductor portion.