Head-Up Display Optical Layout With Selective Reflection Folding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing head-up displays require a large installation space due to the need for mirrors to be positioned far apart to avoid blocking light paths, which complicates their integration into vehicles.
Innovation Solution
A head-up display design that incorporates a selectively reflecting element, such as a directionally selective reflector or polarization-selective reflector, to further fold the beam path, allowing mirrors to be arranged side by side and reducing the overall system volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If mirrors are positioned far apart to avoid blocking light paths, then light path blockage is avoided, but the installation space increases
Solution Approach 1:
The patent introduces a selectively reflecting element that operates in a different dimensional space by being transparent to certain angles and reflective to others. This allows the optical path to be folded back on itself without the mirrors needing to be far apart, resolving the contradiction between avoiding light path blockage and reducing installation space.
Solution Approach 2:
The selectively reflecting element acts as an intermediary between the two mirrors, enabling the optical path to interact with itself. This mediator allows the light to travel from the first mirror to the second mirror and back without requiring large separation distances, thus reducing installation space while maintaining proper light path geometry.
2Reliability
If mirrors are positioned far apart, then proper optical path geometry is maintained, but device complexity increases
Solution Approach 1:
By introducing angular selectivity as an additional dimension to the selectively reflecting element, the patent enables compact mirror arrangement while maintaining proper optical path geometry. The angular dimension allows the system to distinguish between light paths that would otherwise be confused in a compact configuration.
Solution Approach 2:
The selectively reflecting element changes the parameter of reflectivity based on the angle of incidence. This parameter change allows the same element to be transparent for the incoming light path from the imaging unit and reflective for the returned light path from the first mirror, maintaining optical path geometry in a compact configuration.
3Volume of stationary object
If a compact mirror arrangement is used, then installation space is reduced, but light path blockage occurs
Solution Approach 1:
The selectively reflecting element exhibits different optical properties (transparent vs. reflective) at different locations in angular space. This local quality differentiation allows the element to permit light passage in one angular direction while reflecting light from another direction, enabling compact mirror arrangement without light path blockage.
Solution Approach 2:
The patent resolves the light path blockage issue by adding angular dimension to the optical design. The selectively reflecting element uses this additional dimension to differentiate between light paths, allowing compact physical arrangement while maintaining clear light paths through angular selectivity.
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 design reduces the installation space required for the head-up display, simplifying its integration into vehicles by avoiding light path blockages and enabling a more compact arrangement of optical components.
Implementation Method 1
a selectively reflecting element (15). The optical system (12) is designed such that light emanating from the imaging unit (11) strikes the selectively reflecting element (15) and passes through it unhindered, strikes the first mirror (13) and is reflected by it in the direction of the selectively reflecting element (15), is reflected by the selectively reflecting element (15) in the direction of the second mirror (14)
Implementation Method 2
strikes the first mirror (13) and is reflected by it in the direction of the selectively reflecting element (15)
Implementation Method 3
is reflected by the second mirror (14) in the direction of the selectively reflecting element (15), passes through it unhindered and finally strikes the projection surface (21)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a head-up display (10), in particular a head-up display (10) for a means of transportation. The invention further relates to a means of transportation with such a head-up display (10). The head-up display (10) comprises an imaging unit (11) for generating an image and an optical system (12) for projecting the image onto a projection surface (21). The optical system (12) comprises at least a first mirror (13), a second mirror (14), and a selectively reflective element (15). The selectively reflective element (15) is arranged in the optical path between the first mirror (13) and the second mirror (14).