Segmented LED Parallel Arrays for Manufacturing Variation Compensation
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Solution Overview
Problem
Conventional LED light sources face limitations in power conversion efficiency, reliability, and cost due to the need for multiple LEDs connected in series, which are prone to catastrophic failure and require costly sorting to achieve uniform light output, while increasing current to enhance light output decreases efficiency and shortens LED lifespan.
Innovation Solution
A light source utilizing Segmented LEDs connected in parallel to a power bus with a controller, allowing for variable numbers of LEDs to compensate for manufacturing variations and adjust light output, with each Segmented LED divided into N segments to reduce current requirements and increase driving voltage, enabling efficient power delivery and fault tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are connected in series to increase light output, then the total light output increases, but the reliability decreases due to catastrophic failure risk
Solution Approach 1:
The patent divides the LED array into multiple independent parallel strings, where each string contains multiple LEDs in series. This segmentation allows individual strings to fail independently without causing catastrophic failure of the entire system, thus improving reliability while maintaining high light output through the combined contribution of multiple strings.
Solution Approach 2:
The patent changes the electrical configuration parameter from pure series connection to a hybrid arrangement combining series and parallel connections. By adjusting the number of strings and LEDs per string, the system can optimize both light output and reliability, allowing continued operation with failed LEDs through the parallel redundancy.
2Illumination intensity
If current is increased to enhance light output, then the total light output increases, but the power conversion efficiency decreases
Solution Approach 1:
The patent segments the total current requirement across multiple parallel strings, allowing each LED to operate at optimal current levels for maximum efficiency. This avoids the efficiency loss associated with over-driving individual LEDs at high currents, while still achieving high total light output through the combined output of multiple efficiently-operating LEDs.
Solution Approach 2:
The patent uses multiple copies of LEDs operating in parallel, each contributing to the total light output. This allows the system to achieve high illumination intensity through the cumulative effect of multiple efficient, low-current LEDs rather than relying on a single high-current LED with poor efficiency.
3Illumination intensity
If current is increased to enhance light output, then the total light output increases, but the LED lifespan decreases
Solution Approach 1:
The patent divides the light output requirement across multiple parallel LED strings, allowing each LED to operate at lower, lifespan-extending current levels. The cumulative light output from multiple long-lived, low-current LEDs achieves the desired illumination intensity without sacrificing LED lifespan through excessive current stress.
Solution Approach 2:
The patent changes the operating current parameter from high to low, compensating for the reduced individual LED output by increasing the number of parallel LEDs. This parameter change extends LED lifespan while maintaining adequate total light output through numerical multiplication of individual contributions.
4Manufacturing precision
If LED sorting is performed to achieve uniform light output, then the light output uniformity improves, but the manufacturing cost increases
Solution Approach 1:
The patent segments the LED array into multiple parallel strings with variable numbers of LEDs. This allows compensation for manufacturing variations by adjusting the number of LEDs in each string rather than requiring precise sorting of individual LEDs. The segmented architecture provides a simpler, lower-cost method to achieve uniform overall light output.
Solution Approach 2:
The patent introduces dynamic adjustability in the number of LEDs per string, allowing the system to be tuned during assembly to compensate for manufacturing variations. This dynamic configuration approach replaces costly pre-sorting with a simpler post-assembly adjustment process, reducing manufacturing costs while achieving uniform light output.
5Illumination intensity
If larger area chips are used to increase light output, then the light output per LED increases, but the cost per LED increases due to decreased yield
Solution Approach 1:
The patent segments the light output requirement across multiple smaller, lower-cost LEDs rather than using fewer larger, higher-cost LEDs. By using multiple smaller chips with better manufacturing yield and lower individual cost, the system achieves the same total light output at lower overall cost, eliminating the need for expensive large-area chips.
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 power conversion efficiency, improves reliability by allowing continued operation with failed LEDs, and reduces manufacturing costs by enabling fine-tuning of light output without the need for extensive LED sorting, while maintaining LED lifespan.
Implementation Method 1
Light emitting diodes (LEDs) are an important class of solid-state devices that convert electric energy to light
Data Source
AI summary
A light source and method for making the same are disclosed. The light source includes a plurality of Segmented LEDs connected in parallel to a power bus and a controller. The power bus accepts a variable number of Segmented LEDs. The controller receives AC power and provides a power signal on the power bus. Each Segmented LED is characterized by a driving voltage that is greater than 3 times the driving voltage of a conventional LED fabricated in the same material system as the Segmented LED. The number of Segmented LEDs in the light source is chosen to compensate for variations in the light output of individual Segmented LEDs introduced by the manufacturing process. In another aspect of the invention, the number of Segmented LEDs connected to the power bus can be altered after the light source is assembled.