Windshield HUD Edge Tilting for Sharp Virtual Images
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Solution Overview
Problem
Visual field display apparatuses in motor vehicles face challenges such as a limited field of view and the creation of mutually offset double images due to double reflections at optical interfaces, which hinder the effectiveness of virtual display images and contact-analog superimpositions.
Innovation Solution
A method that tilts vertical image element edges in the virtual display image to align with a specific tilt angle, combined with a reflection-suppressing deflection arrangement using planar pixel arrangements and prismatic reflection surfaces, to overlay and suppress double images, allowing for a broader field of view and improved image sharpness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If a conventional projection optical unit is used in the HUD, then the display image can be generated, but the field of view is restricted and the installation space requirement is large
Solution Approach 1:
The projection optical unit is segmented into multiple independent projection units, each responsible for a specific region of the windshield. This allows the system to achieve a broader overall field of view while each individual unit maintains a compact form factor with reduced installation space requirements.
Solution Approach 2:
The patent transitions from a single large-scale projection system to multiple smaller projection units distributed across different spatial positions and angles. By utilizing multiple dimensions (spatial distribution, angular positioning), the system achieves an expanded field of view without increasing the installation space of individual components.
2Ease of manufacture
If the projection screen has two optical interfaces, then the reflection and display function is achieved, but double reflection causes mutually offset double images
Solution Approach 1:
The patent converts the harmful effect of double reflection into a beneficial one by intentionally designing the projection screen with specific optical properties. The double reflection is harnessed to create the desired virtual image depth effect, while the screen's optical characteristics are optimized to minimize image offset and maintain sharpness.
Solution Approach 2:
The patent modifies the optical parameters of the projection screen, such as the refractive index, thickness, and surface coatings, to control the reflection characteristics. By adjusting these parameters, the system achieves the desired virtual image effect while compensating for and minimizing the negative impact of double reflection on image quality.
3Object-affected harmful factors
If additional measures are taken to suppress interfering reflections, then the blinding effect is reduced, but the device complexity increases
Solution Approach 1:
The patent introduces an intermediary element, such as a polarization filter or beam splitter coating, on the projection screen to manage interfering reflections. This intermediary component selectively transmits or reflects light based on polarization or angle, reducing the blinding effect from ambient light reflections while maintaining the visibility of the projected image, all with a relatively simple structural addition.
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 enhances the field of view significantly, allowing for contact-analog 3D effects and improved image clarity by eliminating double images and suppressing interfering reflections, enabling more effective virtual content overlay in the driver's visual field.
Implementation Method 1
double reflection of a projection light beam at two optical interfaces of a partly transparent reflecting projection screen
Implementation Method 2
deflection means such as a matrix-like arrangement of small lenses, for example, are provided in the beam path between the display unit and the windshield, the deflection means deflecting the light beams from different luminous spots in different emission directions
Data Source
AI summary
A method operates a visual field display device, in particular for a motor vehicle, which is designed to produce a projection light beam with a display content and to project the display content onto a partially transparent reflecting projection screen, in particular a front window of the motor vehicle, such that a virtual display image which is superimposed into a field of vision of a user is generated behind it. The method determines image element edges having vertical or a vertical component in the virtual display image to be superimposed and tilts the image element edges thus determined to a respectively adapted tilt angle with respect to the vertical, such that double images of the respective image element edges in the virtual display image are offset with respect to each other in the horizontal direct for the user due to double reflections of the projection light beam on two optical boundaries of the projection screen and appear substantially sharp.