Waveguide Head-Mounted Display for Hyperstereopsis Correction
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Solution Overview
Problem
Conventional display systems for head-mounted or helmet-mounted applications suffer from hyperstereopsis due to sensors being positioned at unnatural stereo separations, causing distorted depth perception and mass distribution issues, particularly in aviation environments where gravitational forces and ejection scenarios are a concern.
Innovation Solution
A waveguide-type display system integrates a sensor device and image source within the same optical path using a beam splitter and diffractive elements, allowing for reduced mass and natural interpupil alignment, mitigating hyperstereopsis and optimizing mass distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional sensors are mounted on the side of a helmet at a separation larger than interpupil separation, then the sensors can be positioned away from the center of the head, but this causes hyperstereopsis effect and distorted depth perception
Solution Approach 1:
The patent uses optical waveguides to create a virtual copy of the sensor position at the correct interpupil separation. The actual physical sensors remain mounted on the helmet side, but optical copying mechanisms (waveguides with diffractive elements) create virtual images at the proper stereo separation, eliminating hyperstereopsis while maintaining positioning flexibility
Solution Approach 2:
Optical waveguides act as intermediary elements between the physically mounted sensors and the user's eyes. The waveguides capture light from sensors positioned at non-standard locations and redirect it to appear as if coming from the correct interpupil separation, mediating between mechanical mounting constraints and optical perception requirements
2Manufacturing precision
If conventional large and heavy sensors are mounted on a helmet, then the sensors can be positioned at correct interpupil separation, but this increases mass on the front of the helmet and may cause clashes with helmet visor
Solution Approach 1:
The system uses optical waveguides to create virtual images of sensors at the correct interpupil separation without requiring physical sensors to be mounted at that location. This allows proper stereo alignment to be achieved through optical copying rather than physical placement, reducing actual mass on the helmet front
Solution Approach 2:
The patent replaces the mechanical approach of physically mounting heavy sensors at correct positions with an optical system. Waveguides and diffractive elements substitute for mechanical sensor placement, achieving proper interpupil separation alignment through light manipulation rather than mechanical positioning of heavy components
3Object-affected harmful factors
If optical techniques are used to fold intensifier objective lenses from the centre of the forehead to correct interpupil separation, then hyperstereopsis is avoided, but the system becomes large and heavy when installed on a helmet
Solution Approach 1:
The patent employs thin waveguide plates as the core optical element, replacing bulky conventional optical folding systems. These thin film waveguides can be integrated into the helmet structure without adding significant weight, while still achieving the necessary optical path folding to correct interpupil separation and eliminate hyperstereopsis
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 waveguide-type display system effectively reduces hyperstereopsis by using a sensor and image source in the same optical path, providing accurate depth perception and minimizing mass on the helmet, enhancing user experience and safety in aviation environments.
Implementation Method 1
A beam splitter may be provided for directing light from the image source to the coupling region and directing light from the coupling region to the sensing device
Implementation Method 2
The diffractive element is arranged at the viewing region to diffract light received from the forward scene along said line of sight to the image sensing optical arrangement and to diffract light from the display optical arrangement towards a user along said line of sight
Implementation Method 3
a sensor device and image source within the same optical path using a beam splitter and diffractive elements
Data Source
Figure 1
Figure 2
AI summary
A primary waveguide (12) and a coupling waveguide (14) are arranged soa user (16) can view light from a forward scene (18) through the primary waveguide (12). An image source (20) generates an image which isdiffractivelycoupled into the primary waveguide (12) and internally reflected to an exit area (34) for diffraction towards the user (16). Light from the forward looking scene (18) isdiffracted into the primary waveguide (12) to be internally reflected and coupled to a image intensifier tube assembly (42). The image intensifier tube assembly (42) enhances light from the forward looking scene (18) and drives the image source (20) such that an image of the enhanced light is overlaid on light from a forward scene (18) at exit area (34).