Head-Up Display Light Guiding Unit for Road Surface Projection
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Solution Overview
Problem
Conventional head-up display devices struggle to effectively display virtual images on a road surface without compromising transmittance and contrast, especially when the display panel is inclined to achieve a vertical projection.
Innovation Solution
A display device incorporating a light guiding unit with a step-like structure and optical fibers, which directs light from a display panel to a mirror, allowing for parallel projection of images onto a road surface without the need for panel inclination, thus maintaining optimal transmittance and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the display panel is inclined to achieve vertical projection on the road surface, then the virtual image can be displayed vertically, but the transmittance and contrast of the display panel decrease
Solution Approach 1:
The light guiding unit is divided into multiple light guiding elements (optical fibers or waveguides) with different lengths, each corresponding to a different irradiation surface. This segmentation allows different portions of the display to be projected at different angles, achieving vertical projection while keeping the display panel itself parallel to the road surface, thus maintaining display performance.
Solution Approach 2:
The light guiding unit acts as an intermediary between the display panel and the road surface. It receives light from the display panel and redirects it to the road surface at the desired angle through its structured geometry, eliminating the need to incline the display panel itself while achieving vertical projection.
2Reliability
If the display panel is kept parallel to the road surface, then transmittance and contrast are maintained, but the virtual image cannot be projected vertically on the road surface
Solution Approach 1:
The light guiding unit serves as a mediator that decouples the orientation of the display panel from the projection angle. The display panel remains parallel to the road surface for optimal performance, while the light guiding unit's stepped structure redirects light to achieve vertical projection on the road surface.
Solution Approach 2:
The solution moves the angle adjustment from the display panel plane to the light guiding unit's depth dimension. By varying the length of light guiding elements in the vertical dimension, different projection angles are achieved without changing the horizontal orientation of the display panel.
3Device complexity
If a conventional head-up display device is used, then the system structure is simple, but the virtual image cannot be accurately displayed on the road surface
Solution Approach 1:
The light guiding unit is segmented into multiple elements with precisely controlled different lengths. This segmentation enables accurate control of light paths for different display regions, achieving accurate virtual image positioning on the road surface while maintaining a relatively simple overall system structure.
Solution Approach 2:
The invention changes the geometric parameter (length) of the light guiding elements to control projection characteristics. By adjusting the length parameter of each light guiding element, the projection angle and virtual image position are precisely controlled, achieving accurate road surface display.
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
Enables the accurate and clear display of virtual images parallel to the road surface, reducing driver distraction and maintaining display panel performance by avoiding the need for panel inclination, which can decrease transmittance and contrast.
Implementation Method 1
a light guiding unit having an incident surface and an irradiation surface, the incident surface being parallel to the display surface and facing the display surface, the irradiation surface being parallel to the display surface and configured to emit a light entered from the incident surface
Implementation Method 2
a mirror configured to reflect an image projected from the display panel through the light guiding unit
Data Source
AI summary
A display device includes a display panel having a display surface, a light guiding unit disposed at a display surface side of the display panel, the light guiding unit having an incident part and an irradiation part, the incident part being parallel to the display surface and facing the display surface, the irradiation part being parallel to the display surface and configured to emit a light entered from the incident part, the irradiation part having a plurality of irradiation surfaces whose positions in a direction orthogonal to the incident part differ depending on a position on the display surface, and a mirror configured to reflect an image projected from the display panel through the light guiding unit.