Head-Up Display Housing With Frangible Impact Protection
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Solution Overview
Problem
Existing head-up display devices in vehicles are dangerous during pedestrian impacts, particularly in the bottom windshield zone, as they exert excessive forces on the pedestrian's head due to rigid attachment and limited deformation capabilities.
Innovation Solution
A head-up display device with a housing comprising walls with frangible portions that allow the covering wall to move closer to the lower edges upon impact, reducing the reaction force by breaking the frangible portion when a certain force is exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the head-up display device is rigidly attached to the dashboard cross-member, then vibrations are prevented from affecting the projection of images, but excessive forces are exerted on the pedestrian's head during impact
Solution Approach 1:
The housing transitions from a rigid static structure to a dynamic structure with frangible portions that can break under impact forces. The covering wall is connected to the front, rear and side walls through frangible portions that remain intact during normal operation but break when impact force exceeds a threshold, allowing the covering wall to move toward the lower edges and reduce impact force on pedestrians while maintaining projection stability during normal use.
Solution Approach 2:
The structural parameters of the housing are changed by introducing frangible portions with controlled strength characteristics. These portions are designed to maintain structural integrity under normal vibrations and operational loads, but are engineered to break at specific force thresholds during pedestrian impact, thereby changing the mechanical response of the device from rigid to compliant under extreme conditions.
2Volume of moving object
If the space between the bottom zone of the windshield and the dashboard cross-member is restricted, then the device can be compactly arranged, but the device dimensions must be reduced or impact forces increased
Solution Approach 1:
The housing is designed with frangible portions that enable dynamic response to impact forces. Within the constrained space, the covering wall can move toward the lower edges when frangible portions break, providing a deformation mechanism that reduces impact force without requiring additional space or reducing device dimensions.
3Strength
If the covering wall is made rigid to protect internal components, then component protection is improved, but impact forces on pedestrians are increased
Solution Approach 1:
The housing is segmented into rigid portions (front, rear, and side walls) that protect internal components, and a frangible connection system (frangible portions) that controlledly fails under impact. This segmentation allows the covering wall to remain structurally sound for component protection while enabling force reduction through controlled breaking of the frangible connections during pedestrian impact.
Solution Approach 2:
The strength parameters of different housing portions are differentially designed. The front, rear, and side walls maintain high strength to protect internal components, while the frangible portions are designed with lower, controlled strength thresholds that allow them to break under impact forces, thereby reducing the force transmitted to pedestrians.
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
The device effectively reduces the forces exerted on the pedestrian's head during an impact by allowing the covering wall to move into the cavity, thus minimizing injury from the head-up display device.
Implementation Method 1
at least one of the front, and/or rear and/or side walls comprises a frangible portion arranged so as to allow the covering wall to be moved closer to one of the lower edges by breaking said frangible portion under an effort exerted on said covering wall towards one of the lower edges, beyond a given limit
Data Source
AI summary
A head-up display device (1), comprising a housing including a front wall (11), a rear wall and two opposing side walls connecting the side edges of the front wall (11) and the rear wall, and a covering wall (15), each of said walls including an upper edge (110, 120, 130, 140),—the covering wall (15) being connected to the upper edges of the front, rear and side walls so as to cover the internal cavity of the housing (10),—wherein said walls each include a lower edge opposite their upper edge, and at least one of the front (11), and/or rear and/or side walls comprise a frangible portion (55) arranged so as to allow the covering wall (15) to be moved closer to one of the lower edges by breaking said frangible portion.