Head-Up Display Optical System Aberration Correction
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Solution Overview
Problem
Existing head-up display systems face challenges in achieving a high contrast virtual image while maintaining a compact size and minimizing coma aberration and astigmatism, with previous solutions either compromising on image quality or increasing system complexity.
Innovation Solution
A head-up display system that incorporates a refractive optical system with a concave mirror and a lens element having negative power, where the lens element's incident surface is concave, projecting an image onto a transparent reflective member to enhance contrast and correct distortion, allowing for a smaller and more efficient optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional optical system is used to achieve a larger enlarging ratio, then the system size increases and coma aberration and astigmatism worsen, but if a compact system is designed, then the enlarging ratio decreases and image quality deteriorates
Solution Approach 1:
The optical system is divided into multiple functional components: a display unit, a first reflecting unit (concave mirror), a second reflecting unit (plane mirror), and a refractive unit (negative meniscus lens). Each component performs a specific function in the optical path, allowing the system to achieve compact size while maintaining image quality through coordinated design of discrete elements
Solution Approach 2:
The first reflecting unit employs a concave mirror with a curved reflective surface, and the refractive unit uses a negative meniscus lens with curved surfaces. These curved geometries are specifically designed to correct coma aberration and astigmatism while achieving the required enlarging ratio within a compact form factor
2Manufacturing precision
If multiple optical components are added to improve image quality and reduce aberration, then the system complexity increases, but if the system is simplified, then image quality and contrast decrease
Solution Approach 1:
The patent combines multiple optical functions into an integrated projection optical system where the reflecting units and refractive unit work together in sequence. The first reflecting unit provides initial beam direction and magnification, the second reflecting unit adjusts the optical path, and the refractive unit corrects aberrations and focuses the image, achieving high image quality through functional integration
Solution Approach 2:
The refractive unit (negative meniscus lens) acts as an intermediary element that receives light from the reflecting units and performs critical functions of aberration correction and image focusing before projection. This intermediary component enables the system to achieve high image quality without requiring complex adjustments to the primary reflecting elements
3Length of stationary object
If the optical path length is increased to improve image projection quality, then the system size increases, but if the optical path is shortened, then image contrast and visibility decrease
Solution Approach 1:
The optical system utilizes three-dimensional spatial arrangement with the first reflecting unit positioned at a specific height and the second reflecting unit arranged to fold the optical path. This multi-dimensional configuration allows the light to travel an effective optical path length sufficient for image quality while the physical footprint remains compact due to the folded geometry
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 presents a virtual image with high contrast and corrected distortion, maintaining a compact size by optimizing the optical path and lens configuration, ensuring excellent visibility across the entire viewpoint region without obstructing the driver's view.
Implementation Method 1
a first concave mirror and a second concave mirror which are disposed to face oppositely at a relative angle θ, and the display information of the display element is made incident on the first concave mirror at an incident angle φ(θ) and outgone from the second concave mirror at an outgoing angle ψ(θ)
Implementation Method 2
The cylindrical concave lens is placed in an optical path so that the center axis of the lens becomes perpendicular to a plane containing an optical axis bended by the first concave mirror and the second concave mirror
Data Source
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AI summary
Head-up display (100) projects an image on windshield (220) to allow an observer to visually recognize a virtual image. Head-up display (100) includes display device (110) and projection optical system (120). Projection optical system (120) includes refractive optical system (121) and concave mirror (122). Display device (110) displays an image to be displayed. Projection optical system (120) projects the image to be displayed on display device (110) to a visual point of the observer. Refractive optical system (121) includes at least one optical element. Concave mirror (122) has a concave reflection surface. Refractive optical system (121) is positioned between display device (110) and concave mirror (122) on an optical path. A surface of the optical element to which light of the image to be displayed on display device (110) is first incident is a concave surface.