LED Arrays Segmented for Low Current Density Operation
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Solution Overview
Problem
Conventional LED lamps face challenges with high cost and reduced luminous efficacy due to operating LEDs at high current densities, leading to increased heat generation, optical losses, and shorter lifetimes, which hinder widespread adoption despite lower operating costs.
Innovation Solution
The use of arrays of relatively small LED units operating at near peak efficacy, with each unit maintained at low current densities to minimize heat and maximize light output, allowing for more efficient light extraction and reduced thermal management costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LEDs are operated at high current densities to increase light output, then power consumption is reduced, but luminous efficacy decreases and heat generation increases
Solution Approach 1:
The invention divides a single high-power LED into multiple smaller LED units operating in parallel. Each small LED unit operates at low current density (below 10 A/cm², preferably 1-5 A/cm²) to maintain high luminous efficacy (above 100 lm/W), while the combined array provides the required total light output. This segmentation allows the system to achieve high power consumption efficiency without sacrificing luminous efficacy, as each individual unit operates in its optimal efficiency range.
2Use of energy by moving object
If LEDs are operated at high current densities to increase light output, then power consumption is reduced, but heat generation increases
Solution Approach 1:
By segmenting the LED system into multiple small units operating at low current densities, the heat generation per unit is significantly reduced. Each small LED generates less heat individually, and the distributed architecture allows for better thermal management across the entire array, preventing the heat accumulation problems associated with single high-power LEDs.
3Use of energy by moving object
If LEDs are operated at high current densities to increase light output, then power consumption is reduced, but lifetime decreases
Solution Approach 1:
The invention uses multiple small LED units operating at low current densities (1-5 A/cm²), which is well below the degradation threshold. Low current density operation significantly reduces electrothermal stress, current crowding effects, and material degradation, all of which contribute to LED lifetime. By operating each unit in this low-stress regime, the system achieves extended lifetime while maintaining high power efficiency through the combined output of multiple units.
4Ease of manufacture
If LEDs are operated at high current densities to increase light output, then manufacturing cost is reduced, but optical losses increase
Solution Approach 1:
The invention employs multiple small LED units with simpler, smaller packaging requirements compared to a single large-power LED. The small LED units have smaller epitaxial structures and require less complex thermal management components, reducing per-unit manufacturing costs. Additionally, the low current density operation minimizes optical losses from heat-induced wavelength shifts, lens degradation, and phosphor efficiency reduction, thereby improving overall optical efficiency.
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 approach results in lower purchase and operating costs, increased luminous efficacy, and extended LED lifetimes, making LED lighting more economically viable and efficient.
Implementation Method 1
light-emitting diodes (LEDs) which convert electrical energy to optical energy
Implementation Method 2
phosphors, which absorb light at a first wavelength and re-emit the light at a second wavelength
Data Source
AI summary
In various embodiments, lighting systems include a carrier having a plurality of conductive elements disposed thereon and a light-emitting array. The light-emitting array is disposed over the carrier and includes a plurality of light-emitting diodes (LEDs), each of which has at least two electrical contacts electrically connected to conductive elements.