Automotive Head-Up Display Ghost Image Reduction via Extended Virtual Image Distance
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Solution Overview
Problem
Conventional automotive head-up display systems using ordinary windshields suffer from the ghost image phenomenon, where a second virtual image interferes with the primary image, hindering driver visibility and requiring expensive wedged windshields or optical coatings to resolve.
Innovation Solution
An automotive head-up display system utilizing an ordinary windshield with a display device that includes an image source and an optical imaging module, where the imaging light is projected onto the windshield to form virtual images at a distance greater than 8 meters from the driver, minimizing the ghost image ratio to less than 0.5% without the need for wedged windshields or optical films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an ordinary windshield is used in a head-up display system, then the system cost is reduced, but a ghost image phenomenon occurs that hinders driver visibility
Solution Approach 1:
The patent changes the virtual image distance parameter to be greater than 8 meters from the driver. This parameter change causes the ghost image to move to a position where it coincides with the primary image in the driver's visual field, making the ghost image imperceptible. The optical imaging module is specifically designed to project images at this extended distance, resolving the ghost image problem while using ordinary windshields.
2Object-affected harmful factors
If a wedged windshield is used to eliminate the ghost image, then the ghost image phenomenon is resolved, but the fabrication cost increases significantly
Solution Approach 1:
Instead of changing the windshield structure (wedge angle), the patent changes the virtual image distance parameter to greater than 8 meters. This alternative parameter change achieves ghost image elimination through optical geometry rather than physical windshield modification, avoiding the complex and expensive wedged windshield fabrication process.
3Object-affected harmful factors
If optical coating or film is applied to the windshield to eliminate ghost image, then the ghost image phenomenon is reduced, but the system complexity and cost increase
Solution Approach 1:
The patent eliminates the need for optical coatings or films by changing the virtual image distance parameter. The optical imaging module is designed to project images at a distance that naturally positions the ghost image coincident with the primary image, achieving ghost image elimination through optical geometry rather than additional optical layers.
4Object-affected harmful factors
If the virtual image distance is increased to greater than 8 meters, then the ghost image ratio is reduced to less than 0.5%, but the optical imaging module design becomes more challenging
Solution Approach 1:
The patent establishes the virtual image distance parameter as greater than 8 meters, which mathematically ensures the ghost image ratio falls below 0.5%. The optical imaging module is designed with specific optical elements and configurations to achieve this extended imaging distance, balancing the parameter requirement with practical implementability.
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
Effectively eliminates the ghost image problem, providing clear and comfortable imaging for drivers while reducing system costs by using standard windshields and maintaining high-quality virtual images with minimal aberrations and distortions.
Implementation Method 1
The inner surface and the outer surface reflect the imaging light to the driver to respectively form a first virtual image and a second virtual image
Data Source
AI summary
An automotive head-up display system with an ordinary windshield comprises an ordinary windshield and a display device, wherein the distance between the inner surface and the outer surface of the ordinary windshield is equal across the ordinary windshield, and the inner surface and the outer surface are non-processed and free of any optical film. The display device includes an image source and an optical imaging module. Compared with the traditional technologies, the automotive head-up display system with an ordinary windshield of the invention can effectively solve the ghost/double image problem and reduce the assembling and production costs of the automotive head-up display system without using the wedged windshield or any optical film.