Vehicle Window Light Guide Coupling to Limit Thermal Bond Stress
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Solution Overview
Problem
Existing vehicle windshields with elongated light coupling elements made of plastic face adhesive bond detachment due to thermal expansion differences between glass and plastic materials, leading to stress and detachment issues.
Innovation Solution
The use of multiple, short, individual light coupling elements made of glass or plastic, each with a wedge-shaped cross-section, attached to the windshield's inner pane using adhesive bonding, potting compound, or a holding device, ensuring limited adhesive surface area and matching refractive indices to minimize thermal expansion effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a lighting device is integrated into a vehicle pane, then the vehicle interior can be illuminated and information can be displayed to the driver or passengers, but the structural integrity and strength of the pane are reduced due to the interruption of the pane structure by the lighting device
Solution Approach 1:
The lighting device is merged with the vehicle pane by integrating the light guide structure directly into the pane assembly. The light guide is positioned in the recess of the pane and optically coupled with the lighting element, creating a unified structure that maintains pane integrity while providing lighting functionality.
Solution Approach 2:
The lighting device components are nested within the pane structure. The light guide is nested in the recess of the vehicle pane, and the lighting element is nested within or coupled to the light guide, allowing the lighting function to be embedded without compromising the overall pane strength.
2Illumination intensity
If a lighting device is integrated into a vehicle pane, then the vehicle interior can be illuminated, but the manufacturing complexity increases due to the need to integrate multiple components (lighting element, light guide, reflector, diffuser) into the pane structure
Solution Approach 1:
Multiple lighting components (light guide, reflector, diffuser) are merged into a single integrated lighting device assembly that is designed as one unit. This integration reduces the number of separate manufacturing steps and simplifies the overall manufacturing process compared to assembling separate components.
Solution Approach 2:
The vehicle pane structure is designed to serve multiple functions: it provides the structural barrier function of the pane while simultaneously housing the lighting device components. The recess in the pane serves both as a structural feature and as the mounting location for the light guide, reducing the need for additional dedicated lighting structures.
3Illumination intensity
If the pane structure is interrupted to accommodate a lighting device, then lighting functionality is achieved, but the aesthetic appearance of the vehicle exterior is compromised due to visible disruptions in the pane surface
Solution Approach 1:
The lighting device is positioned in a localized recess area of the vehicle pane, concentrating the structural interruption in a small, discrete location rather than disrupting the overall pane continuity. This allows the majority of the pane surface to maintain its aesthetic appearance while providing lighting functionality in a specific local area.
Solution Approach 2:
The light guide is designed with a shape that corresponds to the recess in the pane, creating a visual match between the lighting device outline and the recess contour. This design choice helps the lighting device blend into the pane structure, reducing the visual impact of the interruption and maintaining aesthetic appearance.
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 design reduces adhesive bond detachment and improves adaptation to windshield curvature, enhancing light guidance and illumination quality while minimizing material and thermal stress.
Implementation Method 1
the light guide is configured to distribute the light generated by the lighting element over an extension area of the vehicle pane
Data Source
Figure 1
Figure 2~4
Figure 5~7
AI summary
A vehicle pane (3) with a light guiding layer (10) on the inner side of the pane and with a lighting device (4), which introduces light into the light guiding layer (10) by means of a light input coupling device, characterized in that the lighting device (4) has at least two LEDs (11), and in that each LED (11) is assigned a light input coupling element (12), via which light from the respective LED (11) is introduced into the light guiding layer (10).