Multibeam Diffraction Grating Near-Eye Display Accommodation Support
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Solution Overview
Problem
Conventional near-eye displays lack the ability to provide accommodation support, limiting their use in applications requiring comfortable viewing at close distances, such as virtual and augmented reality systems, due to the inability to emit light and provide adequate focus depth cues.
Innovation Solution
A near-eye display employing a multibeam diffraction grating-based backlight that produces a plurality of different views of an image by diffractively coupling light from a light guide, allowing these views to be projected at various locations within the eye box, thereby supporting accommodation and providing focus depth cues through retinal blurring and accommodation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional near-eye displays are used, then the display can be positioned close to the user's eye, but the display cannot provide accommodation support or emit light for comfortable viewing
Solution Approach 1:
The display is segmented into multiple light guides, each corresponding to a specific depth plane. Each light guide emits light at a different angular direction to create virtual images at different distances, enabling accommodation support by providing focus depth cues for multiple depth planes simultaneously
Solution Approach 2:
A diffractive optical element is introduced as an intermediary between the light guide and the user's eye. This element diffracts light into multiple angular directions, creating a light field that provides both the virtual image and the necessary accommodation cues without requiring the physical display to be at the virtual image distance
2Use of energy by stationary object
If passive displays are used, then power consumption is low, but the displays cannot emit light
Solution Approach 1:
The display uses LED light sources with adjustable brightness parameters to emit light only when and where needed. The system dynamically controls the illumination intensity of different light guides based on the displayed content and environmental conditions, maintaining low overall power consumption while enabling light emission for the multiview display function
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 comfortable and immersive viewing experiences by allowing users to focus on images closer than the normal accommodation range, mitigating accommodation-convergence discrepancies in 3D imagery, and providing a 'glasses-free' 3D viewing experience.
Implementation Method 1
a multibeam diffraction grating at a surface of the light guide... diffractively coupling light from a light guide using the multibeam diffraction grating to produce a plurality of light beams
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
A near-eye display and a binocular near-eye display system provide a plurality of different views of an image to different locations within an eye box to impart focus depth cues to a user. The near-eye display includes a multibeam diffraction grating-based display configured to provide the different views and an optical system configured to relay the different views to the different locations within the eye box. The binocular near-eye display system includes a pair of the multibeam diffraction grating-based displays and a binocular optical system configured to provide and relay a stereoscopic image pair representing a three-dimensional (3D) scene to a corresponding pair of laterally displaced eye boxes.