LED Positioning on PCB via Solder Flow Outlets
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Solution Overview
Problem
Existing light devices with LEDs on printed circuit boards face challenges in achieving accurate positioning due to limitations in pick and place methods and soldering processes, leading to inefficiencies and artifacts in light distribution, especially when dealing with multiple LEDs.
Innovation Solution
A light device design that incorporates a printed circuit board with a conductive substrate and insulation layer, featuring strategically placed outlet spaces and openings for solder flow to guide and position LEDs accurately, allowing for enhanced positioning accuracy and reduced thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pick and place methods are used to position LEDs on the printed circuit board, then the positioning accuracy is improved to a tolerance of at most 25 μm, but this accuracy is reduced again by the subsequent soldering process and is not sufficient for many applications
Solution Approach 1:
The patent applies preliminary action by pre-positioning the LED on the printed circuit board with high accuracy using pick and place methods (achieving 25 μm tolerance) before soldering. The LED is temporarily fixed in the correct position, and the soldering process is then performed while maintaining this pre-established positioning accuracy, thereby preserving the high precision through the subsequent soldering step.
2Temperature
If the contacting area is significantly larger than the corresponding LED for thermal spreading, then thermal management is improved, but the displacement of the LED during mounting is limited only by the layer opening of the lacquer layer, reducing positioning accuracy
Solution Approach 1:
The patent applies segmentation by dividing the contacting area into two distinct zones: a first contacting area specifically for electrical contact with the LED, and a second contacting area adjacent to it for thermal spreading. This segmentation allows the electrical contact zone to maintain precise positioning (since the LED can be accurately placed on it), while the thermal spreading function is fulfilled by the extended second contacting area that does not interfere with positioning accuracy.
3Reliability
If the lacquer-free zone is made larger than the size of the chip-shaped LED to prevent contacting problems, then electrical contact reliability is improved, but the positioning accuracy is limited by the larger lacquer-free zone dimensions
Solution Approach 1:
The patent applies segmentation by dividing the lacquer-free zone into two functional areas: a first contacting area that is precisely sized to match the LED dimensions for accurate positioning and electrical contact, and a second contacting area that extends beyond the LED to provide additional thermal spreading and contact reliability. This segmentation allows the LED to be precisely positioned on the first area while the second area provides the necessary margin for contact reliability without compromising positioning accuracy.
4Manufacturing precision
If the smallest possible quantities of solder are used to enhance positioning accuracy, then positioning precision is improved, but the risk of poor electrical and thermal connection increases
Solution Approach 1:
The patent applies segmentation by dividing the solder application into two distinct zones: a first solder area applied to the first contacting area for ensuring reliable electrical and thermal connection, and a second solder area applied to the second contacting area for enhancing thermal spreading and mechanical bonding. This segmentation allows sufficient solder quantity to be used for connection reliability without compromising positioning accuracy, as the solder is distributed across the segmented areas rather than concentrated in a single location that would interfere with LED placement 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 solution enables improved positioning accuracy and efficiency in light device assembly, reducing artifacts and thermal resistance, while maintaining cost-effectiveness and simplicity, particularly suitable for applications requiring high efficiency like effect lighting.
Implementation Method 1
A solder is typically used for the electrical contacting and fixing of the chip-shaped LEDs on the printed circuit board. This solder is heated enough that it melts and forms a type of solder cushion
Implementation Method 2
the printed circuit board can have a lacquer layer, which is deposited on the conductive substrate and is used as electrical insulation
Data Source
AI summary
A light device may include a printed circuit board having at least one conductive section. An LED may be electrically connected and fixed on a conductive section of the printed circuit board by means of a soldered connection. The printed circuit board may also include a coating-type insulating layer and/or the conductive section has an edge. The fixing region of the LED is connected to a discharge space by means of an outlet, so that during the production process, melted solder can flow off in a defined manner. The arrangement and/or embodiment of the outlet is such that in a preferred direction of movement of the LED is developed in order to position same in a defined manner.