Curved Scanning Surface for Head-Up Display Distortion Correction
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Solution Overview
Problem
Conventional head-up displays face challenges in miniaturization and cost reduction while maintaining image quality, with existing solutions often requiring additional correction optical elements that increase size and expense.
Innovation Solution
The head-up display apparatus incorporates a scanning optical system with a curved to-be-scanned surface element and a virtual image optical system using a magnifying concave mirror, which projects an intermediate image onto a combiner like a windshield, eliminating the need for additional correction elements and optimizing beam spot diameter control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a free-form surface lens is arranged in the preceding stage of the image forming unit to correct distortion, then the viewability of the virtual image is improved, but the device size and cost increase
Solution Approach 1:
The patent applies curvature to the to-be-scanned surface of the intermediate image (making it convex toward the user) to inherently correct image distortion and control beam spot diameter, eliminating the need for additional free-form surface lenses. This curvature-based solution resolves the contradiction by achieving distortion correction through geometric design rather than complex optical elements.
2Reliability
If additional correction optical elements are added to improve image quality, then the viewability is improved, but the device size increases
Solution Approach 1:
The patent makes the to-be-scanned surface of the intermediate image serve multiple functions: it acts as both the image formation surface and the distortion correction surface, while also controlling beam spot diameter. By integrating these functions into a single curved surface, the patent eliminates the need for separate correction optical elements, thereby maintaining image quality without increasing device volume.
3Measurement precision
If the beam spot diameter on the to-be-scanned surface is reduced to improve resolution, then the image quality is improved, but the position tolerance of the intermediate image becomes stricter
Solution Approach 1:
The patent uses the convex curvature of the to-be-scanned surface to naturally control and optimize the beam spot diameter across the scanning area. The curved geometry ensures that the beam spot remains appropriately sized throughout the field of view, achieving high resolution while maintaining reasonable position tolerance through geometric optics rather than requiring extremely tight manufacturing tolerances.
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 configuration reduces image distortion, allows for increased robustness, and achieves a compact, cost-effective design that maintains high image quality and reliability, even with user head movements.
Implementation Method 1
a virtual image optical system including a magnifying concave mirror for reflecting and magnifying the intermediate image to form a virtual image
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An image display apparatus includes a light source device including a light source unit; a scanning optical system including an image forming unit on which an intermediate image is formed by light from the light source unit; and a virtual image optical system configured to guide light of the intermediate image by using a reflecting mirror and a curved transmissive reflection member. The scanning optical system includes an optical scanning unit configured to scan the light from the light source unit in a main scanning direction and a sub-scanning direction of the image forming unit. The image forming unit is a transmissive member curved with a convex surface toward the reflecting mirror.