PCB LED Misalignment Compensation via Optical Sensing
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Solution Overview
Problem
Conventional techniques for attaching LEDs to a printed circuit board (PCB) often result in misalignment due to process tolerances, leading to sub-optimal operational conditions and non-ideal beam characteristics in applications like automobile headlights.
Innovation Solution
The method involves creating modified alignment features on the PCB by using a metal film and a modifying component, such as a metal ring, which is optically aligned based on the position of the LEDs to offset any misalignment, ensuring precise alignment with secondary optics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional techniques are used to attach LEDs to a PCB, then the manufacturing process is simple and fast, but the alignment precision between LEDs and secondary optics deteriorates due to process tolerances
Solution Approach 1:
The patent applies preliminary action by creating modified alignment features on the PCB before mounting the secondary optics. The process involves: (1) mounting LEDs to the PCB first, (2) optically sensing the actual positions of the LEDs, (3) modifying the alignment features based on the sensed positions to compensate for misalignment, and (4) then mounting the secondary optics to these modified features. This preliminary modification of alignment features ensures that the final alignment precision is improved without requiring complex real-time adjustment mechanisms during the optics mounting process.
2Ease of manufacture
If conventional alignment features are used on the PCB, then the manufacturing process is simple, but the beam characteristics deteriorate due to misalignment with secondary optics
Solution Approach 1:
The patent applies dynamics by making the alignment features adaptive rather than static. The alignment features are modified based on the actual measured positions of the LEDs, allowing the system to adapt to process variations. This dynamic adjustment transforms the rigid, pre-defined alignment features into flexible features that can accommodate misalignments, thereby maintaining both manufacturing simplicity and alignment precision.
3Productivity
If standard mounting holes are used for aligning PCB with support surface, then the manufacturing is straightforward, but the alignment accuracy with secondary optics is insufficient due to tolerance accumulation
Solution Approach 1:
The patent applies feedback by implementing an optical sensing step that measures the actual positions of the LEDs after they are mounted on the PCB. This measurement feedback is then used to modify the alignment features on the PCB. The feedback loop closes the gap between the ideal design positions and the actual LED positions, compensating for tolerance accumulation and achieving high alignment accuracy without sacrificing manufacturing 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 achieves precise alignment of LEDs with secondary optics, reducing misalignment tolerance to less than 100 microns, resulting in optimal beam characteristics and improved illumination system performance.
Implementation Method 1
one or more light emitting diodes (LEDs) may be mounted on the PCB. A position of the one or more LEDs mounted on the PCB may be optically sensed
Data Source
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AI summary
LEDs for an illumination system may be mounted on a PCB. The PCB may be provided with alignment features such as oversized holes for connection to a support surface. Using optical sensing of the position of the mounted LEDs, the space made available by the alignment features may be reduced and aligned to create modified alignment features. The modified alignment features may be created by adding a modifying component and aligned based on the sensed positions of the mounted LEDs. The positioning of the modifying component may offset misalignment of the LEDs with the PCB. An opening in the modified alignment feature may receive a bolt or alignment pin for connection to the support surface. The support surface may be aligned with the secondary optics, resulting in the LEDs being aligned with the secondary optics irrespective of misalignment of the LEDs with respect to the PCB.