Cross-Board LED Resistor Layout for Cooler Automotive Lighting

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Solution Overview

Problem

LED lighting sources in motor vehicle applications experience performance deterioration due to thermal issues, which conflicts with the need for miniaturization and aesthetic design, particularly in automotive lamps where simultaneous powering of different lighting functions is rare.

Innovation Solution

A lighting circuit assembly with two separate LED matrices and resistor networks, where each network is mounted on a different electronic printed circuit board, allowing for efficient thermal dissipation without affecting the powered LEDs, and optimized electrical connections to reduce the number of cables between boards.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LED matrices and resistor networks are mounted on the same PCB, then device complexity is reduced and manufacturing is simplified, but thermal dissipation is insufficient causing LED performance deterioration

Engineering Contradiction:
ImproveLED performance stabilityVSAvoidcircuit board configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the lighting system into separate functional modules: LED matrices are mounted on one PCB while resistor networks are mounted on a different PCB. This segmentation isolates the thermal dissipation function from the LED lighting function, allowing each component to operate in its optimal thermal environment without interfering with the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The resistor networks, which serve as thermal dissipation components, are extracted from the LED matrix PCB and placed on a separate PCB. This extraction removes the source of thermal interference from the LED circuit, preventing temperature-induced performance deterioration while maintaining the necessary electrical connection functions.

Inventive Principle:
Principle #2Taking out (Extraction)

2Area of stationary object

If miniaturization is pursued for PCB design, then aesthetic appearance and space utilization improve, but thermal dissipation capability is reduced

Engineering Contradiction:
ImprovePCB areaVSAvoidthermal dissipation
Core Design Contradiction:
Area of stationary objectVSTemperature

Solution Approach 1:

The patent transitions from a single-plane PCB layout to a multi-PCB three-dimensional configuration. By distributing components across multiple PCBs in space, the system achieves improved thermal management without increasing the footprint area of individual PCBs, thus maintaining miniaturization benefits while enhancing thermal dissipation capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Temperature

If separate PCBs are used for LED matrices and resistor networks, then thermal dissipation is improved, but number of electrical connections and cables increases

Engineering Contradiction:
Improvethermal dissipationVSAvoidelectrical connections
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent combines the LED matrices and resistor networks into an integrated lighting system where multiple PCBs work together as a unified assembly. The separate PCBs are electrically connected through standardized interfaces and cable assemblies, creating a modular system that achieves thermal separation while maintaining electrical integration and reducing overall connection complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively mitigates the performance decline of LEDs due to temperature by isolating thermal dissipation components from active LED circuits, ensuring optimal performance and reduced electrical connections, thus enhancing the reliability and efficiency of LED lighting in automotive applications.

Implementation Method 1

Other resistors of the network of resistor elements mainly have a function of thermal dissipation of the power absorbed

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4021148B1Lighting circuit assembly
Publication Date: 2024.10.30 MARELLI AUTOMOTIVE LIGHTING ITAL SPA
  • EP4021148B1 patent drawingFigure 1
  • EP4021148B1 patent drawingFigure 2
  • EP4021148B1 patent drawingFigure 3

AI summary

A lighting circuit assembly, in particular for lighting or signaling devices of motor vehicles, comprising a first lighting circuit and a second lighting circuit, configured and/or controlled so as to perform different lighting functions. The two lighting circuits comprise, on respective electronic printed circuit boards, respective matrices of LED lighting sources and respective networks of resistor elements configured so as to determine the driving current of the respective matrices of LEDs. At least some resistor elements of a first network of resistor elements are mounted on the second electronic board and at least some resistor elements of the second network of resistor elements are mounted on the first electronic board.