Self-Aligning LED Array via Reflow Surface Tension
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Solution Overview
Problem
Surface mount technology components, such as LEDs, can randomly move during the reflow process, leading to inadequate final positions in adaptive driving beam headlight systems, resulting in irregular beam patterns that compromise safety.
Innovation Solution
A method is developed to enable self-aligning LEDs by creating a die architecture with a specific solder bond line thickness on a printed circuit board, utilizing surface tension forces during the reflow process to pull LEDs into optimal positions, achieving high placement accuracy of less than or equal to 50 micrometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If surface mount technology is used to mount LEDs on a printed circuit board, then productivity and ease of manufacture are improved, but manufacturing precision deteriorates due to random movement during reflow process
Solution Approach 1:
The patent implements self-alignment of LEDs during the reflow process by designing the solder joint geometry and material properties to automatically guide the LED to its correct position through surface tension forces, eliminating the need for high-precision placement equipment while maintaining manufacturing efficiency
Solution Approach 2:
The patent changes the physical state of the solder from solid to liquid during reflow, utilizing the liquid state's surface tension properties to enable self-alignment. By controlling temperature parameters to melt the solder temporarily, the system achieves precise LED positioning without requiring precise mechanical placement
2Ease of manufacture
If standard reflow process is used for mounting LEDs, then ease of manufacture is improved, but manufacturing precision deteriorates due to random LED position shifts
Solution Approach 1:
The patent converts the harmful random movement of LEDs during reflow into a beneficial self-alignment mechanism. By designing the solder joint with specific geometric and material properties, the surface tension forces that cause movement are redirected to guide the LED to its correct position, transforming a manufacturing defect into a precision-enhancing feature
Solution Approach 2:
The solder joint acts as an intermediary element that mediates between the LED and the printed circuit board. During reflow, the molten solder creates surface tension forces that guide the LED to its correct position, serving as a self-aligning mechanism that simplifies the overall assembly process while ensuring precision
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 method ensures high placement accuracy of LEDs, enabling precise alignment and stable beam patterns for automotive headlight applications, enhancing safety by maintaining consistent light projection.
Implementation Method 1
The self-alignment effect comprises creating surface tension forces while the one or more solders are molten that pull or hold the one or more light-emitting diodes to or at final positions
Data Source
AI summary
A method for enabling self-aligning light-emitting diodes is provided. The method includes printing a die architecture including solders having a bond line thickness according to a printed circuit board design and placing light-emitting diodes in corresponding placement positions onto the solders. The method includes implementing a reflow process that includes a self-alignment effect for the light-emitting diodes. The self-alignment effect comprises creating surface tension forces while the solders are molten that pull or hold the light-emitting diodes to or at final positions.