Vehicle Head-Up Display Curved Diffuser Eyebox Illumination
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Solution Overview
Problem
Existing head-up display devices for vehicles face challenges in achieving homogeneous illumination of the eyebox, leading to inefficiencies in light distribution and increased electrical power consumption, as they struggle to effectively focus and direct light to the desired areas without causing losses at the edges.
Innovation Solution
The solution involves a diffuser with a curved exit surface and optical structures on its exit surface, designed to bundle light within a specific angular range, ensuring that light is focused and directed efficiently into the eyebox, reducing losses and enhancing illumination homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a flat diffuser is used to distribute light, then light coverage area is increased, but light distribution homogeneity deteriorates and edge losses increase
Solution Approach 1:
The patent applies curvature to the diffuser surface, specifically designing a curved exit surface instead of a flat one. This curvature is optimized to redirect light rays from the edge regions toward the center of the eyebox, thereby improving light distribution homogeneity while maintaining full eyebox coverage. The curved geometry transforms the light path to compensate for edge losses inherent in flat diffuser designs.
2Loss of energy
If light is directed into a narrow angular range, then light efficiency is improved, but eyebox illumination homogeneity deteriorates
Solution Approach 1:
The patent implements local quality by applying different optical characteristics to different regions of the diffuser. Specifically, the exit surface curvature varies across the diffuser area, with different curvature radii in different zones. This allows edge regions to redirect light at different angles compared to central regions, achieving both efficient light utilization and homogeneous eyebox illumination through spatially varying optical properties.
3Illumination intensity
If the diffuser redirects light from edge regions, then light distribution homogeneity is improved, but the structure complexity increases
Solution Approach 1:
The patent resolves the complexity issue by using a mathematically defined curved surface geometry rather than complex multi-element optical systems. The exit surface is designed with a specific curvature radius that can be manufactured using standard optical fabrication techniques. This single curved surface replaces what would otherwise require multiple optical elements or complex microlens arrays, achieving homogeneous light distribution with relatively simple structure.
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 approach results in improved light distribution and reduced power consumption by ensuring that light is uniformly and effectively projected onto the semi-transparent mirror surface, enhancing the visibility of the virtual image or display for the vehicle driver.
Implementation Method 1
The light is then refracted at the optical structure of the diffuser and directed into the designed angular range, for example 20° circularly.
Implementation Method 2
The curvature of the exit surface is optimized to focus the light in the eyebox
Data Source
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AI summary
The invention relates to a display device (12) as a head-up display for a vehicle (10) with an image generation device (14) which is configured to emit light (16) to display a virtual image (38) or a virtual display (38), wherein the image generation device (14) comprises a light source (62) and a display unit (64), and the light source (62) emits the light (16) and the display unit (64) displays an image or a virtual display (38).a display device (12), an optical device (18) configured to project the light (16) emitted by the image-generating device (14) onto a display element (26), and a diffuser (46) arranged in a beam path of the light (16) emitted by the light source (62), such that light (16) emitted by the light source (62) enters the diffuser (46) via an inlet surface (48) and exits the diffuser (46) via an outlet surface (50), the outlet surface (50) having an overall curvature to focus the light (16) emitted by the light source (62) into an eyebox (30) of the display device (12). The invention also relates to a vehicle (10) with the above display device (12).The invention further relates to a method for manufacturing a display device (12) as a head-up display for a vehicle (10) comprising providing a diffuser (46) as a substantially flat plate, arranging the diffuser (46) in a beam path of the light (16) emitted by the light source (62), and bending the diffuser (46) so that the entrance surface (48) has an overall curvature in order to focus the light (16) emitted by the light source (62) into an eyebox (30) of the display device (12).