Freeform Mirror AR Head-Up Display for Far-Focus Road Projection
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Solution Overview
Problem
Conventional head-up displays require drivers to repeatedly adjust their focus between a far distance and a fixed image distance of 2 to 3 meters, causing inconvenience while driving, as they cannot display information without shifting focus from the driving perspective.
Innovation Solution
A three-dimensional augmented reality head-up display system using a windshield reflection scheme with a freeform surface mirror to create a virtual 3D image on the ground, allowing information to be displayed as a 3D perspective without requiring eye focus adjustment, by reflecting light from a display device onto the windshield and focusing it on the ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional head-up display projects an image at a fixed distance of 2 to 3 meters, then the image can be clearly displayed, but the driver must repeatedly adjust focus between the far distance and the fixed image distance, causing inconvenience
Solution Approach 1:
The patent transitions from a conventional 2D fixed-distance image display to a 3D virtual image that can be positioned at various distances along the optical axis. The freeform surface mirror creates a three-dimensional virtual image space, allowing the image to be displayed at the driver's far-point distance (300m) rather than a fixed 2-3 meter distance, thereby eliminating the need for focus adjustment while maintaining image clarity
Solution Approach 2:
The patent changes the key parameter of image distance from a fixed value (2-3 meters) to a variable parameter that can be adjusted to match the driver's far-point distance. By using the freeform surface mirror to create a virtual image at 300m distance, the system adapts the image display distance to the driver's natural viewing distance, eliminating focus adjustment requirements
2Ease of operation
If the image is displayed at the driver's far-point distance of 300 meters, then focus adjustment is eliminated, but the optical system becomes more complex requiring freeform surface mirrors and precise alignment
Solution Approach 1:
The patent employs a freeform surface mirror with a complex curved geometry to achieve the desired optical transformation. The freeform surface is specifically designed to collimate light rays from the display device and create a virtual image at the driver's far-point distance, eliminating the need for multiple optical components while achieving the 300m virtual image distance
Solution Approach 2:
The freeform surface mirror acts as an intermediary optical element that transforms the light from the display device into parallel rays that appear to originate from a virtual image at 300m distance. This single intermediary component simplifies the optical system compared to using multiple lenses or mirrors, while still achieving the desired effect of displaying information at the driver's far-point distance
3Use of energy by moving object
If a freeform surface mirror is used to create a virtual 3D image on the ground, then light efficiency is maximized, but the manufacturing and alignment precision requirements increase
Solution Approach 1:
The freeform surface mirror utilizes a specifically designed curved geometry to efficiently direct light from the display device to the driver's eye while creating a virtual image on the ground. The curved surface optimizes light collection and redirection, maximizing light efficiency while the freeform design allows for compact integration within the vehicle's dashboard space
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
Enables drivers to access desired information as augmented reality on the road surface without focusing adjustments, enhancing convenience and safety by projecting virtual 3D images aligned with the driver's viewpoint, while optimizing light efficiency through the optical system.
Implementation Method 1
a freeform surface mirror configured to reflect light from the light source toward a windshield of a vehicle
Implementation Method 2
the windshield may perform a function of simultaneously reflecting the light from the light source reflected by the freeform surface mirror toward an eye-box and transmitting light from outside
Data Source
AI summary
A three-dimensional augmented reality head-up display includes a display device functioning as a light source; and a freeform surface mirror for reflecting light from the light source onto a windshield of a vehicle. An image created by the light from the light source is focused on the ground in front of the vehicle as a virtual image of a three-dimensional perspective, through a reflection method in which the light from the light source is reflected onto the windshield by means of the freeform surface mirror.