Monolithic Multi-Emission LED Chip for Wide-Range Dimming
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Solution Overview
Problem
Optoelectronic semiconductor chips face challenges in achieving dimmability over a wide brightness range while maintaining efficiency, as they typically have a narrow optimum range for operating current, leading to decreased efficiency and increased heat generation when deviating from this range.
Innovation Solution
The semiconductor chip is designed with multiple emission regions, each having a distinct optimum range for operating current, allowing for independent or combined current supply to adjust brightness, and a mesa structure and separation zone to enhance electrical separation and radiation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single emission region with a fixed active zone size is used, then the semiconductor chip structure is simple, but the brightness range is limited and cannot achieve wide dimmability
Solution Approach 1:
The active zone is divided into multiple emission regions with different sizes (first emission region with larger area, second emission region with smaller area). Each emission region can be independently controlled to emit light, enabling the semiconductor chip to achieve wide dimmability over several orders of magnitude by selectively activating different emission regions or combining their outputs.
2Illumination intensity
If the operating current is increased to achieve higher brightness, then the brightness increases, but the efficiency decreases and heat generation increases
Solution Approach 1:
Different emission regions are designed with different sizes to have different luminous flux outputs. The first emission region has a larger active zone area and produces higher luminous flux, while the second emission region has a smaller active zone area and produces lower luminous flux. This allows the system to operate at optimal efficiency points by selecting the appropriate emission region for the required brightness level.
3Adaptability or versatility
If multiple emission regions with different active zone sizes are integrated, then wide dimmability is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
Multiple emission regions with different sizes are monolithically integrated into a single semiconductor chip structure. The emission regions share common semiconductor layers including the active zone, electron transport layer, and hole transport layer, which are formed through a unified growth process. This monolithic integration approach enables wide dimmability while maintaining manufacturing feasibility through standardized fabrication processes.
4Ease of operation
If emission regions are electrically separated, then independent current control is achieved, but the device complexity increases
Solution Approach 1:
A separation zone is introduced between the first and second emission regions to provide electrical separation. This separation zone allows independent current control to each emission region while maintaining a relatively simple overall structure. The separation zone acts as an intermediary element that enables independent operation without requiring complex electrical isolation structures.
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 design enables efficient dimming over several orders of magnitude, reducing assembly complexity and cost, while maintaining color accuracy and brightness adjustment in display applications.
Implementation Method 1
The active zone includes at least one quantum well structure in the form of a single quantum well, SQW for short, or in the form of a multi-quantum well, MQW for short, for generating electromagnetic radiation
Data Source
AI summary
In at least one embodiment an optoelectronic semiconductor chip includes an emission side, an assembly side opposite the emission side, and a semiconductor body. The semiconductor body includes a first semiconductor layer, a second semiconductor layer, and an active zone between the first semiconductor layer and the second semiconductor layer. The semiconductor body further has at least two emission regions arranged next to each other as in view of the emission side. A first emission region includes a first portion of the active zone and a second emission region including a second portion of the active zone. The emission regions are monolithically integrated in the semiconductor body. In a cross-section along a main extension plane of the active zone, the first portion of the active zone has an area at least twice as large as the second portion of the active zone.