HUD Display Device with Multi-Focal Length Imaging
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Solution Overview
Problem
Head-up display (HUD) technology causes eye fatigue due to long-term viewing of a fixed focal plane and fails to effectively display steering information and overlays on the windshield, leading to incomplete information presentation.
Innovation Solution
A display device that alternately outputs first and second light rays with different polarization directions, using a light-splitting assembly and imaging reflecting element to position the images at varying distances from the observer, allowing for adjustable focal lengths and improved depth-of-field, thereby reducing eye fatigue and enhancing information presentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flat image at a fixed focal length is projected onto the windshield, then the image can be clearly displayed, but the driver experiences eye fatigue due to prolonged focusing at a fixed distance
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static fixed-focal-length image to a dynamic multi-focal-length image. The system projects multiple images at different focal lengths (first image at first focal length, second image at second focal length) that can be alternately displayed or simultaneously presented, allowing the driver's eyes to adjust focus dynamically rather than maintaining a fixed focal point, thereby reducing eye fatigue while maintaining image clarity.
Solution Approach 2:
The patent implements parameter changes by varying the focal length parameter of the projected images. Instead of maintaining a constant focal length, the system changes the focal length parameter to create multiple images at different distances (first image at first focal length, second image at second focal length), enabling the driver's visual system to relax and refocus alternately, thus mitigating eye fatigue while preserving clear image display.
2Device complexity
If a flat 2D image is projected, then the display structure is simple, but steering information and overlay information cannot be displayed effectively
Solution Approach 1:
The patent applies the dimensionality change principle by introducing the focal length dimension to the traditional 2D flat image display. By projecting images at different focal lengths (creating a depth dimension), the system can display multiple layers of information (steering information, overlay information, navigation information) that appear at different depths, enabling effective presentation of complex multi-layer information while maintaining relatively simple display hardware structure.
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 reduces eye fatigue by allowing adjustable focal lengths and improves the presentation of steering information and overlays, enhancing the quality and range of application for HUD systems.
Implementation Method 1
a first conversion element, arranged at a light exiting side of the light source assembly, and configured to convert the first light ray which originates from the light source assembly and is carried with the first image to be displayed into a first polarization light, and to convert the second light ray which originates from the light source assembly and is carried with the second image to be displayed into a second polarization light
Implementation Method 2
a light-splitting assembly and a imaging reflecting element, the light-splitting assembly being configured to split light rays to direct the converted first light ray originating from the first conversion element towards the imaging reflecting element in a first direction, and to direct the converted second light ray originating from the first conversion element towards the imaging reflecting element in a second direction different from the first direction
Implementation Method 3
the imaging reflecting element being configured to receive and reflect the first light ray propagating in the first direction and the second light ray propagating in the second direction so as to form the first image by the first light ray and the second image by the second light ray, respectively
Data Source
AI summary
A display device and a display method are provided, the display device including: a light source assembly, configured to output a first light ray carried with a first image to be displayed and a second light ray carried with a second image to be displayed, alternately; a first conversion element, arranged at a light exiting side of the light source assembly, and configured to convert the first light ray carried with the first image to be displayed into a first polarization light, and to convert the second light ray carried with the second image to be displayed into a second polarization light; and a light-splitting assembly and a imaging reflecting element, the light-splitting assembly being configured to direct the converted first light ray originating from the first conversion element towards the imaging reflecting element in a first direction, and to direct the converted second light ray originating from the first conversion element towards the imaging reflecting element in a second direction different from the first direction, and the imaging reflecting element being configured to receive and reflect the first light ray propagating in the first direction and the second light ray propagating in the second direction so as to form the first image and the second image, respectively; the first image and the second image are located at different distances from the imaging reflecting element in a same direction with respect to a predetermined observation location respectively.