Vehicle Display Optical Element Polarization Filter
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Solution Overview
Problem
Conventional display systems for vehicles, such as those using concave mirrors, are susceptible to external light interference, leading to reflections of headlights or sunlight, which can cause glare and reduce the effectiveness of the rear-view image display.
Innovation Solution
A display system incorporating a display element, a first mirror, and an optical element with a wave plate and polarizing element, where the optical element transmits and reflects light to prevent external light from being reflected by the first mirror, and includes a rotatable optical reflector with multiple mirrors to extend the optical path and reduce external light interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a concave mirror is used to display the rear-view image, then the driver can see a virtual image as if displayed ahead of the mirror, but external light (headlights, sunlight) is reflected by the mirror causing glare and reducing image effectiveness
Solution Approach 1:
A polarizing filter is introduced as an intermediary element between the concave mirror and the driver's eye. This polarizing filter selectively transmits light polarized in a specific direction while blocking light polarized perpendicular to that direction. The filter is positioned in the optical path to attenuate externally reflected light that reaches the driver's eye, thereby reducing glare from headlights and sunlight while preserving the rear-view image visibility
Solution Approach 2:
The polarization state of light is utilized as a parameter to differentiate between desired and harmful light. By applying a polarizing filter with a specific polarization axis orientation, the system changes the transmission parameter based on the polarization direction of incoming light. This allows selective attenuation of externally reflected light which typically has different polarization characteristics compared to the rear-view image light
2Device complexity
If the optical element is integrated with the display element, then the structure is simplified, but the optical element cannot effectively reflect external light and transmit reflected light from the first mirror separately
Solution Approach 1:
The optical system is segmented into distinct functional components: the display element, the first mirror, and the optical element with polarizing filter. This segmentation allows each component to perform its specific optical function independently. The optical element is positioned separately from the display element to enable it to intercept and selectively reflect external light while allowing the display element's reflected light to pass through, thereby maintaining high optical effectiveness without unnecessary integration
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 system effectively attenuates external light, reducing glare and improving the clarity and accuracy of the rear-view image displayed to the user by minimizing reflections from external sources.
Implementation Method 1
an optical element that includes a wave plate and a polarizing element
Implementation Method 2
an optical element that includes a wave plate and a polarizing element, the optical element (i) transmits reflected light resulting from the light emitted through the display surface of the display element being reflected by the first mirror
Implementation Method 3
a first mirror that reflects the light emitted through the display surface of the display element
Data Source
AI summary
A display system includes: a display element that includes a display surface through which light showing an image is emitted; a concave mirror that reflects the light emitted through the display surface of the display element; and an optical element that includes a wave plate and a transmissive polarizing plate that is a polarizing element, the optical element facing the concave mirror. The concave mirror and the optical element are each provided separately from the display element. The optical element (i) transmits reflected light resulting from the light emitted through the display surface of the display element being reflected by the concave mirror, and (ii) reflects light from outside off a surface of the optical element, the surface facing the concave mirror, the light from the outside entering the optical element from a side through which the reflected light exits, and being reflected by the concave mirror.