Vehicle HUD Optical Coating Against Solar Damage
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Solution Overview
Problem
Existing head-up display (HUD) systems face challenges in reducing damage to liquid crystal display elements due to solar light, particularly when a large concave mirror is used, which collects and directs intense sunlight towards the display.
Innovation Solution
The proposed solution involves forming a dielectric multilayer film directly on the surface of a mirror or lens within the HUD system. This film selectively reflects or transmits light based on polarizing direction or wavelength, effectively blocking or reducing incident solar light without compromising image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large concave mirror is used to enlarge the virtual image region, then the display area is increased, but the solar light collected by the mirror increases causing damage to the liquid crystal display element
Solution Approach 1:
A polarizing plate is introduced as an intermediary component between the liquid crystal display element and the concave mirror. This polarizing plate selectively blocks polarized solar light while allowing the display light to pass through, thereby protecting the liquid crystal display element from solar light damage without compromising the enlarged display area provided by the large concave mirror
Solution Approach 2:
The polarizing plate is positioned specifically at the location where solar light enters the optical system (between the liquid crystal display element and the concave mirror), providing localized protection exactly where the harmful solar light needs to be blocked while maintaining the overall optical path and enlarged display functionality
2Object-affected harmful factors
If a light polarizing member is pasted on a glass substrate to block polarized solar light, then the liquid crystal display element is protected, but flatness cannot be secured and image quality is reduced
Solution Approach 1:
The polarizing function and the protective function are merged into a single integrated polarizing plate component. This eliminates the need for separate pasting of a light polarizing member on a glass substrate, thereby maintaining flatness and avoiding the image quality reduction that would result from the pasting process
Solution Approach 2:
The polarizing plate is constructed as a composite structure that integrates the polarizing functionality with the protective coverage, providing both solar light blocking and flat surface maintenance in a single component without the need for additional pasting layers that would compromise flatness
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 configuration reliably reduces the impact of solar light on the liquid crystal display element, minimizing damage and maintaining image quality, while also preventing overheating and distortion caused by unwanted light components.
Implementation Method 1
a dielectric multilayer film having a property that selectively reflects/transmits light in a desirable polarizing direction or with a desirable wavelength
Implementation Method 2
the dielectric multilayer film having a property that selectively reflects/transmits light
Implementation Method 3
blocking/reducing the incident solar light entering the apparatus from outside
Data Source
AI summary
The information display apparatus has a housing with an opening and a transparent cover formed on the opening, the housing includes image-light generating means configured to generate image light that displays the image information and an optical system configured to allow a driver of the vehicle to recognize image information based on the image light from the image-light generating means as a virtual image in front of the windshield. When S-polarized light on the windshield is assumed to be a first polarized wave while polarized light that orthogonally crosses the S-polarized light in a polarizing direction is assumed to be a second polarized wave, the image-light generating means is configured to generate the image light made of the first polarized wave, and a transmittance/reflectance control means blocks a part of the first polarized wave and the second polarized wave of incident external light entering the housing from the opening.