AR Stray Light Rejection Layer Slats
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Solution Overview
Problem
Augmented reality systems face difficulties in bright light conditions due to stray light rays being diffracted or refracted by optical components, causing unwanted optical effects like rainbows that impair vision and reduce visibility of augmented information.
Innovation Solution
An augmented reality system with a stray light rejection layer comprising slats arranged at various angles to direct towards the user's notional eye position, reducing high-angle incident light from reaching the optical components and minimizing diffracted or refracted light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If transparent optical components are used to allow users to view both projector light and external environment, then visibility of augmented reality information is improved, but stray light from external sources is diffracted or refracted towards the user's eyes causing rainbow effects that impair vision
Solution Approach 1:
The optical component is segmented into multiple functional layers: a transparent substrate layer for light transmission and a stray light rejection layer with selectively oriented microstructures. This segmentation allows the system to simultaneously transmit desired light while blocking harmful stray light through the directional properties of the microstructured layer.
Solution Approach 2:
The stray light rejection layer introduces local quality variations through microstructures with specific orientation patterns. Different regions of the optical component have microstructures oriented at different angles, creating location-specific light transmission properties that block stray light from particular directions while maintaining transparency for useful light paths.
2Ease of operation
If diffraction gratings are positioned on waveguides to couple light from projector into waveguide and out towards user, then augmented reality light delivery is achieved, but external light rays are also diffracted or refracted towards user's eyes creating unwanted optical effects
Solution Approach 1:
The stray light rejection layer acts as an intermediary element positioned between the external environment and the waveguide optical structures. This intermediate layer selectively intercepts and redirects harmful stray light before it can interact with the diffraction gratings, while allowing desired light paths to proceed unchanged to the waveguide coupling structures.
3Adaptability or versatility
If optical components interact with light from external environment to allow viewing, then transparency and environmental awareness are improved, but high angle incident rays from bright sources are deflected towards user's eyes impairing vision
Solution Approach 1:
The optical component's light transmission properties are made dynamically selective through the microstructured stray light rejection layer. The layer's effectiveness varies based on the angle of incident light, automatically adapting to block high-angle stray light from bright sources while maintaining transparency for lower-angle useful light paths, providing reliable vision quality across diverse lighting conditions.
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 effectively reduces undesirable optical effects such as rainbowing, allowing users to view projected augmented reality images clearly in bright external conditions by blocking high-angle stray light, thereby improving the usability of augmented reality systems in diverse lighting environments.
Implementation Method 1
the stray light rejection layer can advantageously reduce high angle incident rays of external light from reaching the substantially transparent optical component
Implementation Method 2
Diffraction gratings are positioned on or in the waveguides to couple light from a projector into a waveguide. A further diffraction grating structure can then be used to couple light out of the waveguide and towards a user
Implementation Method 3
The optical components, such as the waveguides or prisms, in these applications are typically transparent so that the user can view light from the projector as well as light from their external environment
Data Source
AI summary
An augmented reality system (2) is disclosed for use in bright external conditions. The augmented reality system includes: a projector (6), a substantially transparent optical component (4) that provides augmented reality light to a user, and a stray light rejection layer (12). The stray light rejection layer (12) further comprises a plurality of slats (16) arranged at a plurality of respective angles to effectively reduce high angle incident light from the external environment from reaching the transparent optical component (4).