Vehicle Head-Up Display Backup Optics for Failure Alerts
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Solution Overview
Problem
Head-up display devices for vehicles may fail during imminent danger, causing safety-related information to not be displayed due to failures in the image generation units.
Innovation Solution
A head-up display device that includes an element emitting a secondary light beam, which is transmitted through a deflection mirror and combiner to project an alarm indicator or signaling pattern into the driver's field of vision, independent of the image generation unit, using an electroluminescent light source and modulating intensity/spectrum for visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an image generation unit is used to display safety-related information, then the driver can receive visual information about vehicle status and environment, but the system reliability decreases because the complex electronic image generation unit can fail when imminent danger occurs
Solution Approach 1:
The display system is segmented into two independent subsystems: the primary image generation unit for normal operation and a secondary alarm indicator for critical failures. This segmentation allows each subsystem to be optimized independently, with the alarm indicator being a simple, reliable component that does not depend on the complex image generation unit.
Solution Approach 2:
The system changes the operational parameters of the reflecting mirror by utilizing its second face (normally unused for reflection) to transmit light from the alarm indicator. This parameter change enables the alarm indicator to use the optical path independently from the image generation unit, bypassing the complexity issue.
2Reliability
If a backup alarm indicator is added to the head-up display system, then the reliability improves by providing alternative display path, but the device complexity increases due to additional optical components
Solution Approach 1:
The reflecting mirror is designed with multi-functionality: its first face reflects light from the image generation unit for normal display, while its second face transmits light from the alarm indicator for failure mode display. This universal design allows one component to serve multiple functions without requiring separate dedicated components for each function.
Solution Approach 2:
The alarm indicator uses the existing optical infrastructure (combiner, reflecting mirror, windscreen) to create a copied display path. Instead of building a completely separate optical system, the invention copies the essential optical path elements and uses them for the backup display function, significantly reducing the added complexity.
3Device complexity
If the alarm indicator light beam is transmitted through the reflecting mirror, then the optical path is simplified and components are reused, but the transmission coefficient must be sufficient to ensure visibility
Solution Approach 1:
The system changes the optical parameters of the reflecting mirror by selecting a specific coating material and thickness that provides both the necessary reflection for normal operation and sufficient transmission for the alarm indicator. This parameter optimization ensures that the alarm light maintains adequate intensity after passing through the mirror.
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
Ensures critical information can still be projected into the driver's field of vision even if the image generation unit fails, providing a backup means for displaying alerts or warnings, enhancing safety by maintaining visibility of important information during system failures.
Implementation Method 1
said element includes an electroluminescent light source
Implementation Method 2
said optical projection system comprising a reflecting mirror having a first face and a second face, said first face being turned towards said image generation unit to reflect said primary light beam
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a head-up display device (1) for a vehicle (2) comprising: - an image generating unit (4) generating a primary light beam (7) representing a scene to be displayed, and - an optical projection system (8, 9) for projecting this scene onto an individual (3) situated inside the vehicle, the optical projection system comprising a return mirror (8) having a first face (10) and a second face (11), the first face being turned towards the image generating unit so as to reflect the primary light beam towards a combiner (9) adapted to form an image (16) of the scene visible by the individual. According to the invention, the device comprises at least one element (18) facing the second face of the return mirror and adapted to emit a secondary light beam (19) in the direction of this second face, the secondary light beam being transmitted through the return mirror towards the combiner forming an image (20) of the element visible by the individual.