Anisotropic Polymer Laminates for Rearview Mirror Optical Quality
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Solution Overview
Problem
Existing rearview mirror systems face challenges in providing sufficient luminance for display visibility under ambient light conditions while maintaining a clear and undistorted reflected view, as conventional laminates used in automotive applications often result in image distortions and reduced optical quality due to structural defects and low spatial frequency distortions.
Innovation Solution
A variable reflectance mirror system incorporating an anisotropic birefringent plastic film laminate between a substrate and superstrate, optimized through controlled lamination processes involving heat, pressure, and humidity to minimize structural distortions and ensure adequate flatness, thereby reducing extended distortions and enhancing image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laminates are used in automotive mirror systems, then the structure provides basic optical functionality, but image distortions and reduced optical quality occur due to structural defects and low spatial frequency distortions
Solution Approach 1:
The patent applies controlled lamination parameters including temperature (heating to melt adhesive), pressure (applying uniform pressure during bonding), and humidity control to minimize structural distortions. The lamination process parameters are optimized to achieve SW<3 and LW<3 values, eliminating extended distortions while maintaining the structural integrity of the mirror system
Solution Approach 2:
The patent uses composite laminate structures combining multiple layers including anisotropic films, adhesive layers, and substrate materials. This composite approach allows each layer to contribute specific properties while the controlled lamination process ensures minimal interface distortions, achieving both structural reliability and optical quality
2Illumination intensity
If anisotropic birefringent plastic film laminate is used to transmit polarized light from displays, then display visibility is improved, but maintaining clear reflected view requires precise control of lamination distortions
Solution Approach 1:
The patent controls lamination parameters including heating temperature, pressure distribution, and humidity to minimize structural distortions. These parameter optimizations ensure SW<3 and LW<3 measurements, achieving adequate flatness that allows high display luminance transmission while maintaining clear reflected views without distortion
Solution Approach 2:
The patent uses controlled lamination processes as an intermediary method to bond the anisotropic film to substrates. This controlled bonding process acts as a mediator that transmits display light effectively while minimizing the introduction of structural distortions that would degrade the reflected image quality
3Manufacturing precision
If lamination processes are optimized to minimize structural distortions, then image quality is enhanced, but the manufacturing process complexity increases
Solution Approach 1:
The patent optimizes lamination parameters including temperature, pressure, and humidity control to achieve minimal structural distortions (SW<3, LW<3). While these controlled parameters increase process complexity, they are necessary to eliminate extended distortions and achieve the required optical quality for automotive mirror applications
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 solution effectively transmits polarized light from displays while reflecting orthogonal polarized ambient light, maintaining high reflectance and transmittance values, thus improving display contrast and image clarity in automotive rearview mirrors, meeting stringent automotive industry standards.
Implementation Method 1
a laminate including an anisotropic birefringent plastic film between a substrate and a superstrate that is configured to substantially transmit light of a first polarization and substantially reflect light of a second polarization, the second polarization being orthogonal to the first polarization
Implementation Method 2
an optical element having a proximal side and a distal side, wherein the optical element is adapted to reflect ambient light incident upon the proximal side such as to form reflected light
Data Source
Figure 1~2
Figure 3(A)~3(G)
Figure 4(A)~4(B)
AI summary
Anisotropic film laminates for use in image-preserving reflectors such as rearview automotive mirror assemblies, and related methods of fabrication. A film may comprise an anisotropic layer such as a light-polarizing layer and other functional layers. The film having controlled water content is heated under omnidirectional pressure and vacuum to a temperature substantially equal to or above a lower limit of a glass-transition temperature range of the film so as to be laminated to a substrate. The laminate is configured as part of a mirror structure so as to increase contrast of light produced by a light source positioned behind the mirror structure and transmitted through the mirror structure towards a viewer. The mirror structure is devoid of any extended distortion and is characterized by SW and LW values less than 3, more preferably less than 2, and most preferably less than 1.