AR Optical System Depth-of-Field Separation Vergence-Accommodation Conflict
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Solution Overview
Problem
Conventional AR glasses and helmets cause vergence-accommodation conflict due to a fixed display screen distance, leading to eye discomfort, dizziness, and potential strabismus and amblyopia from inconsistent focusing depth and eye rotation angles when viewing three-dimensional images.
Innovation Solution
An AR optical system with a depth-of-field separation structure, including a convergent lens and semi-transmitting semi-reflecting mirrors, converts light rays into multiple beams with different depths of field, allowing images to be focused at various distances, alleviating the conflict by forming focal planes at different distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed display screen distance is used in conventional AR glasses, then the device structure is simple, but the focusing depth cannot be adjusted causing vergence-accommodation conflict
Solution Approach 1:
The optical system is segmented into multiple independent optical paths, each corresponding to a specific depth of field. The depth-of-field separation structure divides the light from the display screen into multiple beams with different depths of field, allowing the system to provide multiple focusing depths while maintaining a simple fixed-distance display screen structure.
Solution Approach 2:
The patent introduces a new dimension to the optical system by adding the depth-of-field separation structure that creates multiple light beams with different optical paths. This dimensional expansion allows light to reach the eye through multiple paths with different depths of field, resolving the contradiction between simple structure and adjustable focusing depth.
2Reliability
If multiple light beams with different depths of field are created, then vergence-accommodation conflict is alleviated, but the optical system becomes more complex
Solution Approach 1:
The depth-of-field separation structure acts as an intermediary component between the display screen and the user's eye. It receives light from the display screen and transforms it into multiple beams with different depths of field, mediating the interaction between the fixed-distance screen and the eye's accommodation system to reduce visual conflict.
Solution Approach 2:
The optical system dynamically adapts to different viewing needs by providing multiple fixed depth of field options. While the display screen remains at a fixed distance, the optical system creates dynamic flexibility in focusing depth through the separation structure and adjustable optical paths, allowing users to select different focusing planes.
3Ease of operation
If the display screen is positioned at a fixed distance, then the device structure is simplified, but the angle between lines of sight and focusing depth becomes inconsistent
Solution Approach 1:
The optical path is segmented into multiple distinct paths, each with a specific depth of field characteristic. This segmentation allows independent control of optical paths for different depths, enabling the system to match the angle between lines of sight with the appropriate focusing depth for each path, thereby improving eye coordination.
Solution Approach 2:
The system changes the optical path parameters by creating multiple beams with different depths of field through the depth-of-field separation structure. This parameter variation allows the optical system to adjust the relationship between viewing angle and focusing depth, ensuring consistency between eye rotation angle and accommodation for improved ease of operation.
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 user discomfort and improves experience by allowing images with different depths to be seen, mitigating vergence-accommodation conflict and enhancing the perception of three-dimensional images.
Implementation Method 1
a depth-of-field separation structure corresponding to an image source, the depth-of-field separation structure configured to convert a light ray emitted from the image source into a plurality of light beams with different depths of field
Implementation Method 2
a first semi-transmitting semi-reflecting mirror located on a side of the convergent lens away from the depth-of-field separation structure and configured to reflect the plurality of shaped light beams with different depths of field
Implementation Method 3
a convergent lens located on an emergent light path of the depth-of-field separation structure and configured to receive and shape the plurality of light beams with different depths of field
Implementation Method 4
a concave mirror having a preset transmission-reflection ratio and located on a side of the first semi-transmitting semi-reflecting mirror in the reflection emergent light direction, the concave mirror having a concave surface facing the first semi-transmitting semi-reflecting mirror and configured to reflect and converge the plurality of light beams with different depths of field
Data Source
AI summary
An AR optical system includes a depth-of-field separation structure corresponding to an image source, configured to convert light rays emitted from the image source into a plurality of light beams with different depths of field; a convergent lens located on an emergent light path of the depth-of-field separation structure, and configured to receive and shape the plurality of light beams with different depths of field; a first semi-transmitting semi-reflecting mirror located on a side, away from the depth-of-field separation structure, of the convergent lens, and configured to reflect the plurality of shaped light beams with different depths of field towards a set direction; a concave mirror having a preset transmission-reflection ratio configured to reflect and converge the plurality of light beams with different depths of field and then make the light beam incident to a set observation position after passing through the first semi-transmitting semi-reflecting mirror.