Eye Imaging Through Display Backlight for AR Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Augmented reality systems face challenges in maintaining precise geospatial positioning of virtual content in fast-moving environments, such as aircraft, where real objects for anchoring are scarce, leading to instability and poor image quality due to wide beam angles and stray light in mixed reality headsets.
Innovation Solution
A backlight system using a laser light source with a narrow band gap and beam angle, combined with holographic surfaces to precisely control light reflection, reducing stray light and improving image quality by tailoring the beam angle to match the input surface characteristics of compact lens stacks, and a system for tracking the vehicle's and user's position to accurately lock virtual content in space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact arrangement of lenses is used in mixed reality headsets, then the device size is reduced, but stray light increases and image quality deteriorates due to wide beam angles
Solution Approach 1:
The patent changes the beam angle parameter of the light source from wide to narrow (specifically 15-30 degrees) to reduce stray light. This is achieved by selecting light sources with inherently narrow beam angles and using optical elements that further constrain the beam width, thereby eliminating the need for complex lens arrangements while maintaining compact device size.
Solution Approach 2:
The patent extracts and eliminates the harmful wide beam angle characteristic from the light source. By using light sources with inherently narrow beam angles and removing unnecessary lens elements, the design isolates the essential function of light delivery while eliminating the source of stray light problems.
2Illumination intensity
If a wide beam angle is used in the display system, then more light is distributed, but image quality deteriorates due to stray light transmission through the lens stack
Solution Approach 1:
The patent changes the beam angle parameter from wide to narrow (15-30 degrees) to improve image quality. This parameter change ensures that light is distributed only in the intended direction, preventing stray light from reaching the sensor and degrading image quality, while still providing adequate illumination for the display.
Solution Approach 2:
The patent converts the potential harm of limited light distribution into a benefit by using a narrow beam angle light source. The narrow beam naturally confines light to the desired area, eliminating stray light issues while maintaining sufficient illumination intensity for high-quality image delivery.
3Adaptability or versatility
If the display device moves due to external forces, then the device adapts to dynamic environments, but the user's perception of displayed content changes and stability is lost
Solution Approach 1:
The patent implements feedback through sensors that detect device motion and acceleration. This feedback information is used to dynamically adjust the display content and rendering parameters in real-time, compensating for the effects of device movement and maintaining stable perception of virtual objects despite changes in device position and orientation.
Solution Approach 2:
The patent applies dynamics by making the display system adaptive to changing conditions. The system dynamically adjusts content presentation based on real-time device motion data, allowing it to maintain stable visual perception while adapting to dynamic environmental conditions and user movement.
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 solution provides stable and high-quality augmented reality experiences by precisely controlling light distribution and tracking the vehicle's and user's position, ensuring accurate geospatial locking of virtual content even in fast-moving environments with limited real objects.
Implementation Method 1
the backlight includes a laser light source, a holographic surface patterned to expand the laser light into a line
Implementation Method 2
a first waveguide with at least one first holographic surface configured to receive the column of light, wherein the at least one first holographic surface is configured to reflect the column of light out of the first waveguide as a line of light
Implementation Method 3
a second waveguide with at least one second holographic surface configured to receive the line of light, wherein the second holographic surface is configured to reflect the line of light as a two-dimensional plane of light
Data Source
AI summary
Aspects of the present inventions relate to eye imaging system for head worn computer display systems. In embodiments, a camera and infrared light source are positioned behind a backlighting system and directed to image a user's eye through the optical path used for the display.