Transparent Sheet HUD Optics for High-Resolution Vehicle Displays
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Solution Overview
Problem
Conventional information display systems, particularly in vehicles, face challenges such as low light utilization efficiency, high power consumption, insufficient image resolution, and structural restrictions due to large windshield inclination angles.
Innovation Solution
The development of an information display system that includes an image projection apparatus with a light source, a transparent sheet on a glass surface, and a light direction changing unit to efficiently direct image light. This system converts image light into a narrow diffusion angle with specific polarization, allowing for high-resolution displays and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional magnification projection information display system is used, then the system structure is simple, but the light utilization efficiency is low and power consumption is high
Solution Approach 1:
The patent changes the optical parameters of the projection system by replacing the conventional concave mirror with a convex lens, and by controlling the diffusion angle and polarization of image light. These parameter changes enable more efficient light delivery to the observer, improving light utilization efficiency while maintaining a relatively simple system structure
Solution Approach 2:
The patent introduces a liquid crystal display element that can dynamically control the image light characteristics, including diffusion angle and polarization state. This dynamic control allows the system to optimize light delivery efficiency adaptively, resolving the contradiction between simple structure and high light utilization efficiency
2Measurement precision
If a small-sized liquid crystal display element is used to reduce set size, then the device size is reduced, but the projection image resolution becomes insufficient
Solution Approach 1:
The patent improves resolution not by increasing display element size but by optimizing the optical path and light delivery mechanism. By controlling the diffusion angle and using a convex lens with appropriate focal length, the system achieves high-resolution projection from a compact display element, effectively adding an optical dimension to the resolution problem
3Ease of operation
If the image projection apparatus is arranged between the steering and the windshield to accommodate large windshield inclination angles, then the installation space is utilized, but the image light cannot reach the driver's eyes after reflection
Solution Approach 1:
The patent inverts the conventional optical path design by using a convex lens instead of a concave mirror, and by positioning the display element and optical components to work with rather than against the windshield inclination. This inversion allows image light to successfully reach the driver's eyes even with large windshield angles, improving ease of operation without significantly increasing device complexity
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 achieves significant power savings by improving light utilization efficiency and enables high-resolution image display on glass surfaces, including vehicles, while allowing for unidirectional display capabilities that do not obstruct the driver's view.
Implementation Method 1
a light direction changing unit configured to direct a direction of the image light from the image projection apparatus to the transparent sheet in the display region
Implementation Method 2
the image projection apparatus includes an image light characteristic converting unit configured to convert the image light from the light source constituting the image projection apparatus into image light having a narrow diffusion angle and composed of a specific polarization component
Data Source
AI summary
An information display system configured to unidirectionally display an image to inside or outside of a space via a transparent projected member provided in the space includes an image projection apparatus arranged inside the space and configured to generate and project image light by modulating a light flux from a light source, a transparent sheet provided on an inner surface of a display region set on a part of the projected member, and a light direction changing panel configured to change a direction of the image light from the image projection apparatus toward the transparent sheet of the display region, and the transparent sheet includes a retardation plate, an absorption type polarization plate that absorbs a specific polarized wave, and a transparent diffusion sheet material having a light diffusion function, and projects the image light whose direction has been changed by the light direction changing unit to the inside or the outside of the space.