Vehicle Head-Up Display Refractive Optical System
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Solution Overview
Problem
Existing head-up displays face challenges in maintaining visibility and reducing image degradation, particularly in vehicle-mounted systems where the projection onto a windshield results in distortion and chromatic aberration, affecting the clarity and size of the virtual image displayed for the observer.
Innovation Solution
A head-up display system with a refractive optical system that includes a first lens with negative power, a mirror with a concave reflective surface, and a second lens with a Fresnel facet, which projects an image onto a windshield to create a virtual image with reduced distortion and chromatic aberration, allowing for a compact and high-contrast display that maintains visibility without obstructing the observer's forward view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional projection optical system is used, then the system can project images onto the windshield, but the system becomes large in size and causes degradation in visibility due to distortion and chromatic aberration
Solution Approach 1:
The patent applies local quality by using a refractive optical system with asymmetric design where the inner deflection angle differs from the outer deflection angle. This asymmetric configuration optimizes light beam control specifically for the eye box region, suppressing distortion and chromatic aberration locally where the observer views the image, rather than requiring uniform high-quality optics throughout the entire system.
Solution Approach 2:
The patent employs asymmetry principle by designing the refractive optical system with different deflection angles for inner and outer light beams. The inner deflection angle (for beams passing near the vehicle inner side) is made larger than the outer deflection angle (for beams passing near the vehicle outer side). This asymmetric angular configuration corrects image distortion and reduces system size simultaneously by optimizing the optical path specifically for the observer's eye box position.
2Manufacturing precision
If the projection system uses multiple optical elements to reduce distortion, then image clarity improves, but the system becomes more complex and larger
Solution Approach 1:
The refractive optical system in the patent performs multiple functions simultaneously: it projects the image onto the windshield, corrects distortion, suppresses chromatic aberration, and controls the field of view all through a single integrated optical assembly. This multi-functional design eliminates the need for separate correction lenses and mirrors, reducing the total number of optical elements while maintaining high image clarity.
Solution Approach 2:
The patent achieves image quality improvement by optimizing specific parameters of the refractive optical system, particularly the asymmetric deflection angles and the focal length ratios. By carefully controlling these parameters, the system corrects distortion and chromatic aberration through precise optical design rather than adding multiple corrective elements, thus maintaining simplicity while achieving high clarity.
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 system effectively suppresses image degradation and maintains high contrast and clarity across the entire eye box, ensuring a satisfactory virtual image is visible to the observer without compromising forward visibility, even when the observer's position shifts within the eye box.
Implementation Method 1
The projection optical system has a refractive optical system, and projects an image displayed by the display device on an eye box of the observer
Implementation Method 2
The windshield reflects the display light to display a virtual image
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Head-up display (100), which is mounted on a vehicle, performs projection on a transparent reflective member, and allows an observer to visually recognize a virtual image, includes display device (110) that displays an image, and a projection optical system that has refractive optical system (123) and projects displayed image (111) displayed by display device (110) on eye box (300) of the observer. As an angle formed between a vector of a light beam that is incident on refractive optical system (123) and a vector of an output light beam, the angle is greater at a light beam on an image end passing through a vehicle inner side of refractive optical system (123) than at a light beam on an image end passing through a vehicle outer side of refractive optical system (123).