Windshield HUD Optics for Large Virtual Images Without Double Images
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Solution Overview
Problem
Conventional head-up display systems face challenges in achieving a large virtual image size within a desired view range while minimizing double image generation and maintaining high visibility, especially when using a windshield as the reflecting surface.
Innovation Solution
The system employs a concave mirror and optical elements to control the divergent angle of light flux, optimizing the shape and position of optical components to reduce double image conversion and correct distortion and aberration, allowing for high visibility and miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the object point approaches the focal point and the concave mirror is enlarged to increase virtual image size, then the virtual image size increases, but the radius of curvature becomes smaller making it difficult to maintain desired magnification
Solution Approach 1:
The patent introduces a field lens to control the divergent angle of light flux in a new dimensional approach. By adjusting the divergent angle through the field lens rather than solely relying on concave mirror curvature, the system achieves virtual image magnification while maintaining proper magnification control and avoiding the trade-off between image size and magnification precision
2Area of moving object
If the distance from the concave mirror to the virtual image is enlarged to obtain a large virtual image in desired view range, then the virtual image size increases, but the apparatus size increases
Solution Approach 1:
The patent uses a field lens to control light flux divergence, enabling compact apparatus design by managing image formation in a different optical dimension. This allows achieving large virtual image size without proportionally increasing the physical distance between components, thus reducing overall apparatus volume
3Adaptability or versatility
If the divergent angle of light flux is increased to enlarge the view range, then the view range increases, but double image generation increases
Solution Approach 1:
The patent applies preliminary action by using the field lens to pre-control the divergent angle of light flux before it reaches the windshield. This preliminary control of light direction prevents excessive divergence that would cause double image generation, while still achieving an enlarged view range through optimized optical path 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
This approach enables the formation of a virtual image with improved visibility and reduced double images, achieving both large size and clear visibility within a compact design.
Implementation Method 1
a concave mirror and an optical element. The optical element optimizes a shape and a position of the optical element in accordance with a video light flux in which a virtual image is established
Implementation Method 2
The optical element optimizes a shape and a position of the optical element in accordance with a video light flux in which each of the virtual images separated between the display and the concave mirror is established
Data Source
AI summary
The information display apparatus configured to display video information of a virtual image on a reflecting surface of conveyance includes: a display configured to display the video information; and a virtual image optical system configured to display a virtual image at a front of the conveyance by reflecting light emitted from the display by means of the reflecting surface. The virtual image optical system includes a concave mirror and an optical element. The optical element is arranged between the display and the concave mirror, and is configured to correct distortion of the virtual image obtained so as to correspond to a viewpoint position of a driver on a basis of a shape of the concave mirror and a shape of the optical element. The information display apparatus further includes a virtual image double image conversion reducer configured to reduce double image conversion of the virtual image.