Cross-Connected SST Arrays for Junction Failure Tolerance
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Solution Overview
Problem
High voltage solid-state lighting (SSL) devices and arrays face issues with junction failure, leading to reduced performance, stability, and increased variation in bias across individual coupled SSL devices.
Innovation Solution
The implementation of solid-state transducer (SST) arrays with electrical cross-connections, where SST dies are coupled in series and parallel configurations, and additional cross-connection contacts are used to provide intermediate electrical access points, reducing the impact of junction failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If SSL devices are serially coupled in an array to achieve high input voltage, then the light output and flux delivery are improved, but the junction failure risk increases causing performance deterioration and high variation in bias across individual coupled SSL devices
Solution Approach 1:
The SSL array is segmented into multiple independently controllable groups or strings of serially coupled SSL devices. Each string can be independently controlled, so that when one string experiences junction failure, the other strings can continue to operate, thereby maintaining overall system reliability while achieving high light output through the combined illumination of multiple strings.
Solution Approach 2:
The patent changes the electrical configuration parameters by introducing parallel connections between multiple serial strings, transforming the overall array from a single high-voltage series connection to a composite series-parallel configuration. This parameter change allows the system to maintain high illumination intensity while reducing the impact of individual junction failures through alternative current paths.
2Use of energy by moving object
If multiple SSL devices are coupled in series to achieve high voltage operation, then the power supply voltage utilization is improved, but the bias variation across individual coupled SSL devices increases
Solution Approach 1:
The high voltage SSL array is divided into multiple smaller series strings that are then connected in parallel. This segmentation allows each string to have more uniform bias distribution while the parallel configuration maintains efficient power supply voltage utilization. The bias stability is improved because failures or variations in one string do not propagate to other strings.
Solution Approach 2:
The patent introduces intermediate connection points and control structures between the serially coupled SSL devices. These intermediaries allow for better voltage distribution and bias stabilization across the array, enabling efficient power supply utilization while maintaining stable operating conditions for individual SSL devices despite the high voltage series configuration.
3Productivity
If conventional high voltage SSL devices are used in arrays, then the flux delivery is improved, but the manufacturing complexity and packaging difficulty increase
Solution Approach 1:
The patent merges multiple SSL devices into integrated array structures with standardized interconnections. By combining the packaging and interconnection processes into a unified manufacturing approach, the system achieves high flux delivery through multiple devices while reducing the overall packaging complexity compared to individually packaging and connecting high voltage SSL devices.
Solution Approach 2:
The SSL array structure is designed with universal interconnection patterns and standardized mounting configurations that can accommodate multiple SSL devices in various series-parallel arrangements. This multi-functional packaging approach simplifies manufacturing by using the same basic packaging techniques regardless of the specific array configuration needed to achieve the desired flux delivery.
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 configuration enhances the reliability and performance of high voltage SSL devices and arrays by minimizing the effect of individual junction failures, maintaining stable operation, and reducing manufacturing costs.
Implementation Method 1
Light emitting diodes (LEDs) are solid-state devices that convert electrical energy to light, and generally comprise one or more active regions of semiconductor material formed between oppositely doped materials. When a bias is applied across the doped materials, the active region generates light
Data Source
AI summary
Solid-state transducer (“SST”) dies and SST arrays having electrical cross-connections are disclosed herein. An array of SST dies in accordance with a particular embodiment can include a first terminal, a second terminal and a plurality of SST dies coupled between the first and second terminals with at least a pair of the SST dies being coupled in parallel. The plurality of SST dies can individually include a plurality of junctions coupled in series with an interconnection between each individual junction. Additionally, the individual SST dies can have a cross-connection contact coupled to the interconnection. In one embodiment, the array can further include a cross-connection between the cross-connection contacts on the pair of the SST dies.