AR Display Light Guide with Super Surface for VAC Reduction
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Solution Overview
Problem
Vergence accommodation conflict (VAC) in head-mounted displays causes visual discomfort due to inconsistent focus adjustment and binocular convergence, hindering the development of augmented reality near-eye display devices.
Innovation Solution
A display apparatus featuring a light guide element, image source assembly, coupling-out structure, and super surface structure, which includes gratings and nanopillars, allowing for efficient light manipulation and transmission to the user's eyes without the need for bulky optical devices, thereby reducing product size and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional retinal projection display optical system is used, then image projection function is achieved, but device complexity and volume increase
Solution Approach 1:
The patent combines multiple optical functions (light guiding, coupling out, and image projection) into a single integrated light guide element with embedded structures. The coupling-out structure and super surface structure are integrated within the light guide element, eliminating the need for separate optical components and reducing overall system complexity while maintaining image projection functionality.
Solution Approach 2:
The patent implements a nested structure where the coupling-out structure and super surface structure are embedded within the light guide element. The coupling-out structure is positioned at a first surface while the super surface structure is positioned at a second surface, with both structures nested within the same light guide element body, thereby reducing device volume and component count.
2Volume of stationary object
If light guide element with embedded structures is used, then device volume is reduced, but light transmission efficiency may be affected
Solution Approach 1:
The patent applies different optical properties to different regions of the light guide element. The coupling-out structure has specific optical characteristics for coupling light out at the first surface, while the super surface structure has different optical characteristics for projecting images at the second surface. This local differentiation optimizes light transmission efficiency in each region while maintaining compact overall volume.
Solution Approach 2:
The patent employs dynamic light control mechanisms where the coupling-out structure and super surface structure can adaptively manage light propagation. The structures are designed to dynamically optimize light paths and transmission efficiency based on the specific optical requirements at different surfaces of the light guide element.
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 display apparatus provides a compact, aberration-free optical solution that enhances the user's experience by allowing simultaneous observation of real-world and augmented reality images, addressing the VAC issue and simplifying the optical system.
Implementation Method 1
The coupling-out structure is located at a side of the second surface facing away from the first surface and configured to reflect a light reaching the second surface to the first surface
Implementation Method 2
The super surface structure includes two first super surface gratings
Implementation Method 3
configured to transmit lights reaching the first surface that are emitted from the two image source to a left eye and right eye of a user respectively
Implementation Method 4
light waves emitted from the image source are incident from a corresponding side surface into the light guide element
Data Source
AI summary
A display apparatus is disclosed and includes: a light guide element, including a first surface, a second surface arranged opposite to the first surface, and side surfaces connecting the first surface and the second surface; an image source assembly including two image sources at the side surfaces of the light guide element respectively, where light waves emitted from the image source are incident from the side surface into the light guide element; a coupling-out structure at a side of the second surface facing away from the first surface and configured to reflect a light reaching the second surface to the first surface; a super surface structure at a side of the first surface facing away from the second surface and configured to transmit lights reaching the first surface that are emitted from the two image source to a left eye and right eye of a user respectively.