Convex Light Guide Mirror Head-Up Display Placement
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Solution Overview
Problem
The existing head-up display devices with large-sized light guide mirrors have limited degree of freedom in placement, making it difficult to reduce the reflection angle of display light while mounting the image forming reflection surface above the instrument panel, which results in potential interference with the projector and affects the visibility of the virtual image.
Innovation Solution
A head-up display device with a convex light guide mirror and a concave image forming reflection surface, where the projector projects display light onto the combiner, allowing the light guide mirror to be downsized and reducing the reflection angle, thus enhancing the visibility of the virtual image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large-sized light guide mirror with a planar light guide reflection surface is used, then the display light can be reflected toward the image forming reflection surface, but the degree of freedom of placement is low and it is difficult to reduce the reflection angle
Solution Approach 1:
The light guide reflection surface is designed with a convex curved shape instead of a planar surface. This curvature enables the light guide mirror to effectively reflect display light toward the image forming reflection surface while reducing the overall size of the light guide mirror and increasing placement flexibility in the vehicle interior.
2Illumination intensity
If the image forming reflection surface is placed above the upper surface portion of the instrument panel for visibility, then the virtual image visibility is improved, but the reflection angle increases causing asymmetric vertical distortion
Solution Approach 1:
The convex curved light guide reflection surface works in conjunction with the concave image forming reflection surface to control light reflection angles. This curved surface design enables the image forming reflection surface to be positioned above the instrument panel for improved visibility while maintaining appropriate reflection angles to minimize asymmetric vertical distortion of the virtual image.
3Speed
If the projector is installed in the vicinity of the light guide mirror, then the light beam can be directed properly, but the reflected light beam may interfere with the projector affecting visibility
Solution Approach 1:
The convex curved shape of the light guide reflection surface directs the display light beam along a controlled path that reaches the image forming reflection surface and then reflects toward the driver's position. This curved surface design enables proper light beam direction control while spatially separating the reflected light path from the projector, preventing interference and ensuring clear visibility of the virtual image.
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 enables a reduction in the size of the light guide mirror, increasing its placement flexibility and reducing image distortion, while maintaining high visibility of the virtual image by adjusting the reflection angle and focal lengths, thereby improving the overall display performance.
Implementation Method 1
a light guide mirror including a light guide reflection surface configured to reflect the display light from the projector toward the image forming reflection surface
Data Source
AI summary
A head-up display device is configured to project a display light, which is to be reflected by a concave image forming reflection surface, onto a combiner having the image forming reflection surface a combiner to display a virtual image visible to an occupant. The combiner is located above an upper surface portion of the instrument panel. The projector is configured to project a display light in the form of a light beam. A light guide mirror has a light guide reflection surface and is configured to reflect the display light from the projector toward the image forming reflection surface. The light guide reflection surface is convex.