Head-Up Display Laser Polarization and Lens Diffusion
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Solution Overview
Problem
Conventional head-up display devices have limitations in visibility of virtual images formed via transmitting-reflecting members, such as windshields, due to insufficient light diffusion and polarization characteristics.
Innovation Solution
The image display device employs semiconductor lasers with specific polarization properties and a microscopic convex lens structure on the scanned surface element, which diffuses and modulates light to enhance visibility by converting vertically long effective cross-sections to horizontally long ones, improving reflectance and field angles for better image recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional head-up display devices use standard light sources and flat display surfaces, then the device structure remains simple, but the visibility and brightness of virtual images are insufficient
Solution Approach 1:
The patent changes the physical parameters of light by using semiconductor lasers with specific polarization characteristics (S-polarization) and controlled effective cross-section orientations. This parameter change improves visibility without requiring complex structural modifications to the head-up display system
Solution Approach 2:
The patent introduces a microscopic convex lens structure on the scanned surface element, which curves and focuses light in specific directions. This curvature element diffuses light effectively while maintaining a relatively simple overall device structure
2Illumination intensity
If light is directed narrowly to improve brightness, then illumination intensity increases, but the field angle and visibility with head movement decrease
Solution Approach 1:
The patent applies local quality by creating different light diffusion characteristics in different spatial directions through the microscopic convex lens structure. The lens diffuses light preferentially in horizontal directions while maintaining vertical directionality, achieving both brightness and wide field angle simultaneously
Solution Approach 2:
The patent controls the effective cross-section of light to be horizontally long rather than vertically long, changing the dimensional orientation of light propagation. This dimensional change allows light to spread wider in the horizontal plane, increasing field angle while maintaining brightness
3Illumination intensity
If the display surface is made highly reflective, then brightness improves, but the transmitting-reflecting member blocks more ambient light transmission
Solution Approach 1:
The patent changes the polarization parameter of incident light to S-polarization, which has higher reflectance at the windshield interface. This parameter change increases virtual image brightness while maintaining adequate ambient light transmission, achieving better optical performance balance
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 significantly improves the visibility and brightness of virtual images by increasing the reflectance of S polarization components and diffusing light over a wider angle, ensuring clear navigation information display even with head movement.
Implementation Method 1
an image is formed by light from a semiconductor laser
Implementation Method 2
increasing the reflectance of S polarization components
Implementation Method 3
diffusing light over a wider angle
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3C
AI summary
An image display device including a laser light source; an optical element; and a transmitting-reflecting member, the image display device which displays an image by forming the image by light which is emitted from the laser light source and making image light after forming the image to be incident on the transmitting-reflecting member, wherein the laser light source is arranged such that there are more S polarization components of the image light which is incident on the transmitting-reflecting member with respect to the transmitting-reflecting member than P polarization components, and a mobile object including the image display device.