LED Light Engine Common Anode Heat Spreading
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Solution Overview
Problem
Current LED-based light sources lack uniformity and high power capabilities necessary for direct write applications, particularly in maintaining LED junction temperatures within specified limits under increased current conditions.
Innovation Solution
An LED-based high power uniform light engine with a common anode and active heat sink, featuring a high fill factor and enhanced heat management through a heat spreader and thermally conductive adhesives or solder, capable of handling currents significantly higher than rated values while maintaining efficient cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the current through the LED array is increased to achieve high power output, then the light output power increases, but the LED junction temperature rises above specified limits
Solution Approach 1:
The patent extracts the heat management function from the LED array structure by introducing a separate common anode substrate with integrated heat spreading functionality and an active heat sink. This separates the light generation function from the heat dissipation function, allowing high current operation without excessive junction temperature rise.
Solution Approach 2:
The patent transitions from point-contact or line-contact heat management to area-contact heat management by using a common anode substrate that provides thermal coupling across the entire LED array area. This dimensional expansion of thermal management enables efficient heat removal at high power levels.
2Stability of the object's composition
If the LED array is designed with high fill factor to improve uniformity, then the light uniformity improves, but the heat generation increases
Solution Approach 1:
The patent converts the harmful effect of increased heat generation (from high fill factor) into a manageable parameter by implementing the common anode substrate with heat spreading functionality. The heat that would otherwise be a problem is now efficiently distributed and removed, enabling high fill factor designs for improved uniformity.
3Productivity
If the LED array operates at currents significantly higher than rated values, then the productivity increases, but the reliability decreases due to thermal stress
Solution Approach 1:
The patent implements preliminary thermal management measures by integrating the heat spreader and active heat sink into the common anode structure before the LEDs operate at high currents. This pre-established thermal pathway prevents thermal stress accumulation, enabling reliable high-power operation.
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 solution provides a highly uniform and high-power LED light source that effectively dissipates heat, maintaining LED junction temperatures within safe limits even under extreme current conditions, ensuring reliable operation in direct write systems.
Implementation Method 1
an active heat sink which is thermally connected to the common anode
Implementation Method 2
at least one of the common anode and the active heat sink has a cooling capacity of at least four watts per square mm of the radiation area of the LEDs
Implementation Method 3
an electrically and thermally conductive adhesive which joins the heat spreader to the common anode
Data Source
AI summary
An LED-based high power uniform light engine including an array of LEDs having a common anode and a fill factor which exceeds 0.85, the common anode having heat spreading functionality and an active heat sink which is thermally connected to the common anode.