Light Transmission Control via Polarization Ellipticity Adjustment
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Solution Overview
Problem
Existing light transmission control systems, such as those using linearly polarized films, fail to effectively limit visibility of display devices from outside observers while allowing occupants to view the display, especially when occupants wear polarized eyewear, potentially impairing rear-view vision and increasing accident risks.
Innovation Solution
A light transmission control system comprising a combination of a display and a first polarizer with an ellipticity increaser and a second polarizer with an ellipticity adjuster, configured to reduce the polarization ellipticity of light passing through both polarizers, ensuring minimal transmission of visible light and maintaining visibility for occupants wearing polarized eyewear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If linearly polarized films are used to limit visibility of display through vehicle windows, then visibility to external observers is reduced, but occupants wearing polarized eyewear experience impaired vision and potential safety issues
Solution Approach 1:
The patent changes the polarization parameter from linear to circular by introducing a quarter-wave plate that converts linearly polarized light into circularly polarized light. This parameter change allows the system to maintain visibility blocking for external observers while ensuring occupants wearing polarized eyewear can still see clearly, as circularly polarized light does not interfere with polarized lenses in the same way linearly polarized light does.
Solution Approach 2:
The patent employs a composite polarizing system consisting of multiple components: a linear polarizer and a quarter-wave plate combined to form a circular polarizer. This composite structure integrates the light-blocking function of the linear polarizer with the vision-safe function of the circular polarization conversion, resolving the contradiction between external visibility limitation and occupant safety.
2Loss of energy
If linearly polarized films are used to control light transmission, then light transmission to external observers is blocked, but transmission through polarized eyewear is also blocked, impairing occupant vision
Solution Approach 1:
The patent transforms the polarization state parameter from linear to circular using a quarter-wave plate. This change ensures that while linearly polarized light is blocked by external observers' view path, the converted circularly polarized light can pass through polarized eyewear worn by occupants, thereby maintaining both privacy and ease of operation.
3Reliability
If circular polarizers are used instead of linear polarizers, then visibility to external observers is maintained, but privacy protection is reduced
Solution Approach 1:
The patent segments the polarization control function into two distinct components: a linear polarizer that provides the primary light-blocking function for external observers, and a quarter-wave plate that converts the polarization state to circular. This segmentation allows each component to perform its specific function optimally, achieving both privacy protection and occupant safety simultaneously.
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 limits the visibility of display devices through vehicle windows while allowing occupants to see outside, even when wearing polarized eyewear, thereby enhancing safety and privacy by minimizing light transmission to external observers.
Implementation Method 1
linear polarizing means for linearly polarizing light
Implementation Method 2
The ellipticity increaser is configured and oriented with respect to the linear polarizing means such that light of at least one visible wavelength passing from the linear polarizing means through the ellipticity increaser has a first ellipticity of higher than 0.5
Implementation Method 3
The ellipticity adjuster is oriented with respect to the linear polarizer such that light of the at least one visible wavelength passing from the linear polarizer through the ellipticity adjuster has a second ellipticity of higher than 0.5
Implementation Method 4
The ellipticity increaser and ellipticity adjuster are configured and oriented with respect to each other such that light of at least one visible wavelength passing from the linear polarizing means through the ellipticity increaser and the ellipticity adjuster to the linear polarizer has a polarization ellipse with a third ellipticity of less than 0.5
Data Source
AI summary
Light transmission may be controlled using a system that includes a linear polarizing means and an ellipticity increaser associated with a display. The ellipticity increaser is configured and oriented with respect to the linear polarizing means for increasing the ellipticity of light passing from the linear polarizing means through the ellipticity increaser. The system also includes an ellipticity adjuster and a linear polarizer spaced away from the display. The ellipticity adjuster is oriented with respect to the linear polarizer for increasing the ellipticity of light passing from the linear polarizer through the ellipticity adjuster. The ellipticity increaser and adjuster are disposed between the linear polarizing means and the linear polarizer, and are configured and oriented with respect to each other for reducing ellipticity of light passing from the linear polarizing means through the ellipticity increaser and adjuster to the linear polarizer.