Head-Up Display Optical Layout for Polarization Separation
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Solution Overview
Problem
Existing head-up displays struggle to minimize noise between horizontal and vertical polarization while forming multiple images, leading to interference and potential component deterioration from sunlight exposure.
Innovation Solution
A head-up display design incorporating a half-wavelength phase retarder, spaced apart flat mirrors with different inclinations, and a concave mirror to separate image light into horizontal and vertical polarizations, along with a tilting mechanism and cold mirror coatings to minimize interference and sunlight damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a head-up display forms two optical paths using one image source to display multiple information, then the information display capability is improved, but the optical path complexity and device structure become more complex
Solution Approach 1:
The patent divides the image source into multiple emission surfaces (first emission surface and second emission surface), allowing each surface to generate light for different optical paths. This segmentation enables multiple information displays while maintaining a relatively simple overall structure by distributing the light generation function across separate surfaces rather than using a single complex optical path system
Solution Approach 2:
The patent introduces a beam splitter as an intermediary component that receives light from the first emission surface and directs it to the first optical path, while light from the second emission surface proceeds to the second optical path. This intermediary element facilitates the separation of optical paths in a straightforward manner, reducing the complexity that would arise from trying to split a single optical path
2Reliability
If conventional structures are used to separate horizontal and vertical polarization, then the polarization separation is achieved, but the device volume increases
Solution Approach 1:
The patent combines the polarization separation function with the existing optical path structure by using the beam splitter and emission surfaces to simultaneously achieve both light direction and polarization separation. This merging of functions eliminates the need for separate, bulky polarization separation components, thereby maintaining reliable polarization separation while minimizing device volume
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 design effectively separates image light into horizontal and vertical polarizations, reducing noise and minimizing component deterioration, while allowing for the formation of multiple images without interference and protecting against sunlight-induced damage.
Implementation Method 1
an electric polarization conversion element that transmits others of the linearly polarized light emitted from the image source when turned off, and converts others of the linearly polarized light emitted from the image source into linearly polarized light in a second direction perpendicular to the first direction by a half-wavelength when turned on
Implementation Method 2
a prism that refracts some of the linearly polarized light emitted from the image source
Implementation Method 3
a polarization reflection mirror disposed to be spaced apart from the first reflection mirror, reflecting the linearly polarized light in a first direction, and transmitting the linearly polarized light in a second direction
Implementation Method 4
a first reflection mirror that reflects light to a windshield of the vehicle
Data Source
AI summary
A head-up display may comprise: a picture generation unit having an emission surface from which image light is emitted; a half-wavelength phase retarder disposed to face a first area of the emission surface; a first flat mirror configured to reflect image light emitted from a second area of the emission surface; a second flat mirror configured to reflect image light emitted from the half-wavelength phase retarder; and a concave mirror configured to reflect each of the image light reflected by the first flat mirror and the image light reflected by the second flat mirror to a window shield.