AC-Powered LED with Segmented Structures for Continuous Light
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Solution Overview
Problem
Light-emitting diodes (LEDs) connected to alternating current (AC) power sources experience intermittent light generation and risk of damage due to reverse current, limiting their continuous operation and efficiency.
Innovation Solution
A light-emitting device with a novel electrode structure, including a substrate with multiple semiconductor layers and a common electrode connected to both light-emitting structures, allowing for continuous light generation by alternating voltage supply, reducing the risk of damage from reverse current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LED is connected to AC power source, then the LED can be directly powered without additional circuitry, but the LED experiences intermittent light generation and damage due to reverse current
Solution Approach 1:
The LED device is segmented into multiple light-emitting structures (first light-emitting structure and second light-emitting structure) with different conductive types. During different half-cycles of AC power, different structures emit light, ensuring continuous light output while protecting against reverse current damage to any single structure.
Solution Approach 2:
Multiple light-emitting structures with different conductive types are merged into a single device, sharing a common electrode. This combination allows the device to utilize both positive and negative half-cycles of AC power effectively, achieving continuous operation without additional circuitry.
2Device complexity
If LED is connected to AC power source, then the device can operate with simpler circuitry, but the LED is damaged by reverse current
Solution Approach 1:
The device is divided into light-emitting structures with different conductive types (n-type and p-type). Each structure is protected from reverse current by the fact that reverse bias does not cause significant current flow in the opposite conductive type structure, eliminating the need for additional protection circuitry.
Solution Approach 2:
The reverse current that would normally damage a single LED is converted into a beneficial effect by using structures of opposite conductive type. The reverse bias applied to one structure becomes the forward bias for the other structure, turning the harmful reverse current into useful forward current for light emission.
3Ease of operation
If LED is connected to AC power source, then the LED can be powered directly, but light generation is intermittent rather than continuous
Solution Approach 1:
The light-emitting function is segmented across multiple structures with different conductive types. While one structure is inactive during a half-cycle, the other structure emits light, ensuring continuous light generation throughout the entire AC cycle without interruption.
Solution Approach 2:
The device utilizes the periodic nature of AC power by alternating between different light-emitting structures in sync with the AC cycle. This periodic switching between structures ensures that light emission continues without interruption throughout each cycle.
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 device enables continuous light emission while minimizing damage from reverse current, enhancing the operational stability and efficiency of LEDs connected to AC power sources.
Implementation Method 1
Light emitting diodes (LEDs) are semiconductor light-emitting devices that convert current into light
Implementation Method 2
a first light-emitting structure including a first conductive type semiconductor layer, a first active layer on the first conductive type semiconductor layer, and a second conductive type semiconductor layer on the first active layer
Data Source
AI summary
A light-emitting device has a first light-emitting structure a second light-emitting structure on a top surface of the first light-emitting structure, an insulation layer between a top surface of the first light-emitting structure and a bottom surface of the second light-emitting structure; and a first electrode contacted with the second conductive type semiconductor layer and the third conductive type semiconductor layer. The first electrode contacts the insulation layer and the first electrode has a thickness thicker than that of the insulating layer.