Prism HUD Screen Structure for Windshield Ghost Image Separation
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Solution Overview
Problem
Front-mounted head-up displays (HUDs) suffer from a 'ghost' issue due to light rays being reflected by the inner and outer surfaces of traditional windshields, creating an overlapping image, which is difficult and costly to mitigate using wedge-shaped windshields.
Innovation Solution
A head-up display screen with a functional layer featuring prism microstructures protruding from the windshield's inner surface, a reflective layer attached to the lower inclined surfaces of these microstructures, and a protective layer, which separates the main virtual image from the ghost virtual image by controlling the refractive index and angles to achieve effective image separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional windshield is used for front-mounted HUD, then the structure is simple and cost is low, but light rays are reflected by inner and outer surfaces creating overlapping ghost images
Solution Approach 1:
The windshield is segmented into multiple functional layers: a first windshield layer, a head-up display screen layer with prism microstructures, and a second windshield layer. This segmentation allows each layer to perform specific optical functions, separating the main image path from ghost image paths and eliminating overlapping reflections while maintaining overall structural integrity.
Solution Approach 2:
The head-up display screen with prism microstructures acts as an intermediary layer between the driver and the windshield. This intermediary structure controls light ray paths through refraction and reflection, directing main image light while separating ghost image light, thus solving the ghost problem without requiring complex wedge-shaped windshields.
2Reliability
If wedge-shaped windshields are used to mitigate ghost images, then image separation is improved, but manufacturing cost and processing difficulty increase significantly
Solution Approach 1:
Instead of modifying the entire windshield into a complex wedge shape, the invention copies the light-separation function into a separate head-up display screen layer with prism microstructures. This layered approach achieves the same optical separation effect as wedge-shaped windshields but with standard flat windshield manufacturing, significantly reducing processing difficulty and cost.
Solution Approach 2:
The solution moves from modifying the windshield in one dimension (wedge shape) to adding a separate functional layer in another dimension (the head-up display screen with prism microstructures). This dimensional transition allows light separation without compromising windshield manufacturing simplicity.
3Reliability
If a head-up display screen with prism microstructures is added, then main virtual image and ghost virtual image are separated, but device complexity increases
Solution Approach 1:
The head-up display screen performs multiple functions simultaneously: it serves as the display medium for instrument information, provides the prism microstructures for light separation, and acts as an optical element for image projection. This multi-functionality reduces the need for additional separate components, balancing complexity with effectiveness.
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 solution effectively separates the main virtual image from the ghost virtual image, improving visibility of instrument panel information on the windshield, enhancing driving safety and comfort without the high costs and processing difficulties associated with wedge-shaped windshields.
Implementation Method 1
The functional layer includes prism microstructures protruding from the inner side of the attachment surface of the windshield... controlling the refractive index and angles to achieve effective image separation
Implementation Method 2
The reflective layer is at least attached to lower inclined surfaces of the prism microstructures and is configured to reflect the image light towards the driving position
Data Source
AI summary
A head-up display screen, a head-up display assembly, and a vehicle are provided. The head-up display screen is attached to an inner side of an attachment surface of a windshield and configured to reflect image light emitted towards the windshield. The head-up display screen includes a functional layer, a reflective layer, and a protective layer that are sequentially arranged in a direction from the windshield to a driving position. The functional layer includes prism microstructures protruding from the inner side of the attachment surface of the windshield. The reflective layer is at least attached to lower inclined surfaces of the prism microstructures and is configured to reflect the image light towards the driving position. The protective layer covers the reflective layer and the functional layer.