Head-Up Display Mirror Layout for Windshield Distortion Correction
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Solution Overview
Problem
Existing head-up display apparatuses that project virtual images onto a non-planar windshield face challenges in reducing the vertical size of components due to the need for correcting distortion, which complicates the design and installation in vehicles.
Innovation Solution
A head-up display apparatus with a configuration that includes a display-light emitting unit and a concave reflecting mirror, positioned to emit and reflect light in a manner that corrects distortion while maintaining equal optical paths to the user's eyes, allowing for reduced vertical dimensions without compromising image clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the intermediate image is rotated around the longitudinal axis of the moving body to correct distortion, then the virtual image distortion is corrected, but the sizes of the intermediate-image forming apparatus and the reflecting mirror in the vertical direction increase
Solution Approach 1:
Instead of rotating the intermediate image around the longitudinal axis of the moving body, the patent inverts the approach by rotating the intermediate image around an axis perpendicular to the longitudinal axis. This inversion of the rotation axis fundamentally changes the spatial arrangement, allowing distortion correction to be achieved without increasing vertical dimensions. The reflecting mirror is correspondingly rotated around this perpendicular axis, maintaining the inverted configuration throughout the optical path.
Solution Approach 2:
The patent transitions from rotating around the longitudinal axis (one dimension) to rotating around a perpendicular axis (another dimension). This dimensional change in the rotation axis allows the optical components to be arranged in a different spatial configuration, effectively reducing the vertical footprint while maintaining the distortion correction function. The optical path is reoriented to exploit a different spatial dimension for achieving the same optical objective.
2Manufacturing precision
If the intermediate-image forming apparatus and reflecting mirror are disposed in a rotated manner around the longitudinal axis, then distortion correction is achieved, but the device complexity and installation difficulty increase
Solution Approach 1:
The patent simplifies device complexity by inverting the rotation configuration from the conventional longitudinal axis to a perpendicular axis. This inversion creates a more straightforward spatial relationship between the intermediate-image forming apparatus and the reflecting mirror, reducing the complexity of their relative positioning and orientation. The optical path becomes easier to align and install when components are arranged around a perpendicular axis rather than the longitudinal axis.
3Adaptability or versatility
If a conventional head-up display apparatus is used with a non-planar windshield, then virtual image display is achieved, but distortion correction is required which increases component size
Solution Approach 1:
The patent maintains compatibility with non-planar windshields while reducing component size by changing the dimension of rotation from the longitudinal axis to a perpendicular axis. This dimensional change allows the optical system to accommodate windshield curvature and inclination without requiring large vertical dimensions for distortion correction. The perpendicular rotation enables a more compact arrangement that can adapt to various windshield geometries.
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 apparatus achieves a compact design in the vertical direction, enhancing design flexibility and maintaining image quality by equalizing optical paths for both left and right sides, thus improving installation feasibility and reducing component size.
Implementation Method 1
a concave reflecting mirror 20...configured to reflect the display light P1 emitted from the display-light emitting unit 10
Implementation Method 2
the reflecting mirror 20...is configured to correct distortion of a virtual image P3
Data Source
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AI summary
A head-up display apparatus (1) is a head-up display apparatus capable of projecting a rectangular virtual image onto a virtual-image display unit disposed in front of a user in such a manner that a height of a left side of the rectangular virtual image as viewed from the user coincides with a height of a right side thereof. The head-up display apparatus (1) includes a display-light emitting unit (10) having a second inclination angle around the axis parallel to the vertical direction so that the first direction side thereof is closer to the user than the second direction side thereof is, and being configured to emit display light forming a rectangular image corresponding to the rectangular virtual image. The head-up display apparatus (1) includes a reflecting mirror (20) having a third inclination angle around the axis parallel to the vertical direction so that the first direction side thereof is closer to the user than the second direction side thereof is, and being configured to reflect the display light and emit reflected light to the virtual-image display unit.