Vehicle Lighting System Wiring Loop Height and Thermal Expansion
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Solution Overview
Problem
Vehicle lighting systems face challenges with thermal deformation due to temperature changes, leading to disconnection of wiring connections between light emitting diodes and the wiring pattern, especially when exposed to large ambient temperature variations.
Innovation Solution
The lighting system incorporates a surrounding wall member with a linear thermal expansion coefficient equal to or less than the sealing portion, and a wiring configuration with a loop height of 160 µm or less, along with a socket for power supply terminals, to enhance resistance to temperature changes and prevent wiring disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the size and volume of the sealing portion are increased to accommodate high intensity light emitting diodes, then the light intensity is improved, but the thermal deformation increases
Solution Approach 1:
The patent changes the material parameter (linear thermal expansion coefficient) of the surrounding wall member to be equal to or less than that of the sealing portion. This parameter change allows the structure to accommodate the larger sealing portion volume needed for high intensity LEDs while compensating for thermal deformation through matched material properties.
2Illumination intensity
If the sealing portion is made larger to accommodate more light emitting diodes, then the light output is improved, but the wiring connection reliability deteriorates
Solution Approach 1:
The patent modifies the thermal expansion parameter of the surrounding wall member material to match or exceed the sealing portion's expansion coefficient. This ensures that when the sealing portion expands due to heat generation from multiple LEDs, the surrounding wall member expands proportionally, preventing stress concentration that would cause wiring disconnection.
3Adaptability or versatility
If the ambient temperature range is expanded to meet vehicle requirements, then the adaptability is improved, but the thermal deformation influence increases
Solution Approach 1:
The patent directly applies thermal expansion principles by selecting a surrounding wall member material with a linear thermal expansion coefficient equal to or less than the sealing portion. This ensures that across the wide vehicle ambient temperature range (-40°C to +85°C), the surrounding structure and sealing portion expand and contract in a matched manner, minimizing relative movement and thermal deformation stress.
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 configuration significantly reduces the likelihood of wiring disconnection and enhances the overall resistance to temperature changes, ensuring reliable operation across a wide temperature range.
Implementation Method 1
a linear thermal expansion coefficient of the surrounding wall member is equal to or less than a linear thermal expansion coefficient of the sealing portion
Data Source
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AI summary
Disclosed is a lighting system including: a board; a wiring pattern that is provided on a surface of the board and has a wiring pad; a light emitting element that is provided on the wiring pattern and includes an electrode on a surface thereof opposite to a surface thereof provided on the wiring pattern; a surrounding wall member that is provided to surround the light emitting element; a wiring that connects the wiring pad and the electrode; and a sealing portion that is provided inside the surrounding wall member and covers the light emitting element and the wiring. Here, an angle that is formed by a segment that connects a central position of a portion of the board surrounded by the surrounding wall member and a position where the wiring is connected to the wiring pad, and the wiring is 0° to 45°, or 135° to 180°.