Windshield HUD Reflection Suppression for Wide Field of View
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Solution Overview
Problem
Conventional head-up displays (HUDs) in vehicles have a limited field of view and are prone to spurious reflections from ambient light, which can impair user safety and comfort, especially in varying driving situations.
Innovation Solution
A field of view display device with an electrically controllable flat pixel arrangement and a reflection-suppressing deflection arrangement featuring flat reflection surfaces at an acute angle, which projects a virtual display image onto a windshield while suppressing interference reflections, allowing for a significantly expanded field of view and improved safety and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional projection optics are used in HUD, then the display can be compact, but the field of view is limited and only extends to the horizon
Solution Approach 1:
The patent transitions from a conventional telescope-like optical path to a planar light field display architecture. By using a spatial light modulator and waveguide optics, the display expands from a narrow vertical field of view to a wide angular field of view that can exceed 90 degrees, effectively adding dimensional coverage in the horizontal and oblique directions while maintaining compact vertical profile.
Solution Approach 2:
The display system is segmented into distinct functional modules: a spatial light modulator for image generation, waveguide optics for light redistribution and angular expansion, and multiple reflection surfaces for field of view extension. This segmentation allows each component to optimize its function independently, achieving wide field of view without proportionally increasing overall device volume.
2Device complexity
If conventional HUD projection units are used, then the device structure is simple, but spurious reflections from ambient light can glare the user
Solution Approach 1:
The patent introduces waveguide optics as an intermediary between the spatial light modulator and the user's eye. This waveguide acts as a light management intermediary that selectively guides display light to the user while blocking or redirecting ambient light paths, thereby reducing spurious reflections without significantly complicating the overall device structure.
Solution Approach 2:
The system employs wavelength-selective optical elements within the waveguide that differentiate between display light wavelengths and ambient light wavelengths. By using dichroic mirrors and wavelength-specific reflection surfaces, the system allows display light to pass through to the user while reflecting or absorbing ambient light, effectively reducing glare through optical filtering rather than structural complexity.
3Reliability
If the field of view is expanded beyond the horizon, then user safety and comfort improve, but the optical design becomes more complex
Solution Approach 1:
The patent replaces complex mechanical optical adjustment systems with electrically controllable spatial light modulators and programmable waveguide optics. Instead of physically reconfiguring optical paths to achieve different field of view angles, the system uses electronic control of light phases and amplitudes to dynamically adjust the displayed field of view, improving safety and comfort while managing complexity through software control rather than mechanical design.
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 enables a wider field of view beyond the horizon, supports contact-analog 3D representations, and reduces glare, enhancing user safety and comfort by providing a more immersive and distraction-free driving experience.
Implementation Method 1
a reflection-suppressing deflection arrangement arranged on the planar pixel arrangement, which comprises one or more planar reflection surfaces extending along the planar pixel arrangement at a predetermined acute angle thereto and parallel to one another for projecting the generated projection light beam onto a partially transparent reflective projection screen
Data Source
Figure 1~2c
Figure 2d~3b
Figure 3c~4b
AI summary
The invention relates to a method for operating a field-of-vision display device, in particular for a motor vehicle, comprising: an electrically controllable planar pixel assembly for generating a projection light beam having a display content and a reflection-suppressing deflection assembly, which is arranged on the planar pixel assembly and comprises one or more flat reflection surface(s), extending along the planar pixel assembly at a predefined acute angle thereto and parallel to one another, for projecting the generated projection light beam onto a partially transparent, reflective projection pane, in particular a windshield of the motor vehicle, as a result of which a virtual display image shown in a field of vision of a user is generated behind the projection pane, wherein: the one or more reflection surfaces are each light-absorbing on the rear side thereof in order to suppress interfering reflection; at least one (driving) situation parameter is provided, in dependence on which different area segments of the planar pixel assembly are used to generate a desired display content.