Curved HUD Cover Structure to Reduce Eye-Point Ghosting
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Solution Overview
Problem
Conventional head-up display devices struggle to effectively inhibit external light from reaching the eye point, leading to potential ghosting issues that affect the proper display of virtual images.
Innovation Solution
The head-up display device incorporates a transparent cover with a curved portion that thickens from the side of a facing portion towards the eye point, collecting external light onto the facing portion and reducing reflectance, thereby inhibiting external light from reaching the eye point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional transparent cover is used, then the structure is simple, but external light is reflected toward the eye point causing ghosting
Solution Approach 1:
The transparent cover is designed with a curved surface instead of a flat surface. The curvature is specifically configured to reflect external light away from the eye point, converting harmful reflected light into beneficial redirected light that does not interfere with the virtual image display.
Solution Approach 2:
Different regions of the transparent cover have different thicknesses, with the thickness varying from the first surface to the second surface. This local variation in thickness optimizes the light reflection characteristics at different positions, effectively directing external light away from the eye point while maintaining structural integrity.
2Object-affected harmful factors
If the transparent cover thickness is uniform, then manufacturing is easier, but external light reflectance is not sufficiently reduced
Solution Approach 1:
The transparent cover features a non-uniform thickness distribution, with the thickness varying from the first surface to the second surface. This local variation in thickness is specifically designed to control and reduce external light reflectance at different positions, optimizing the anti-ghosting performance.
Solution Approach 2:
The thickness parameter of the transparent cover is varied across different regions rather than maintaining a constant value. This parameter change optimizes the optical path and reflection characteristics, effectively reducing external light reflectance and preventing ghosting.
3Reliability
If external light is not collected, then the structure is simpler, but ghosting occurs due to reflected external light
Solution Approach 1:
The curved surface of the transparent cover acts as a light collection mechanism, gathering external light and redirecting it away from the eye point. This curvature-based light collection approach ensures reliable virtual image display by preventing ghosting without requiring additional complex light collection components.
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 effectively decreases the incident angle and reflectance of external light, preventing ghosting and ensuring the proper display of virtual images by reducing external light interference.
Implementation Method 1
a curved portion having a curved shape, the curved portion includes: a first surface portion located on a side of the reflection mirror; and a second surface portion that is located on a side opposite to the side of the reflection mirror and that collects external light onto the facing portion
Implementation Method 2
the second surface portion that is located on a side opposite to the side of the reflection mirror and that collects external light onto the facing portion
Implementation Method 3
a reflection mirror that is housed inside the housing and that reflects enlarged display light obtained by enlarging the display light emitted from the display instrument toward the reflection member through the opening
Data Source
AI summary
In a head-up display device, a transparent cover closes an opening, and transmits enlarged display light. In the opening, a facing portion that blocks light is erected on the side opposite to the side of an eye point of the opening. The transparent cover includes a curved portion. The curved portion has an inner surface portion that is located on the side of the reflection mirror, and an outer surface portion that is located on the side opposite to the side of the reflection mirror and that collects external light onto the facing portion. Then, the thickness between the inner surface portion and the outer surface portion in a third direction is thickened from the side of the facing portion toward the side of the eye point in a range on the side of the eye point from a lowest point of the transparent cover in the third direction.