Waveguide Diffraction Structures With Refractive-Index Layers for 3D Stability
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Solution Overview
Problem
Conventional 3D displays often cause eye strain and discomfort due to mismatched accommodative responses, failing to accurately present virtual content at different focal planes, leading to unstable imaging and depth perception issues.
Innovation Solution
A diffraction structure with a waveguide substrate, an underlayer, and a top grating surface, each with distinct refractive indices, combined with precise deposition techniques for imprint materials, allows for varied diffraction efficiency and increased field of view, enabling comfortable 3D perception by aligning virtual content with correct focal distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional 3D displays are used to present virtual content, then depth perception is provided, but eye strain and discomfort occur due to mismatched accommodative responses
Solution Approach 1:
The display system segments the virtual content into multiple focal planes, with each plane rendered at a different depth. This allows the accommodative response to match the vergence response for each plane, eliminating the accommodation-vergence conflict that causes eye strain while maintaining depth perception capability
Solution Approach 2:
The patent introduces a temporal dimension by rapidly switching between different focal planes in a sequential manner. This time-multiplexed approach allows the display to present multiple depth layers without requiring the eye to simultaneously accommodate to multiple distances, thereby preventing eye strain while preserving the perception of three-dimensional depth
2Measurement precision
If virtual content is presented at multiple focal planes, then accurate depth perception is achieved, but imaging stability deteriorates
Solution Approach 1:
The system dynamically adjusts the focal plane positions and switching timing based on the user's vergence angle and accommodation state. This dynamic adaptation ensures that each focal plane is presented at the optimal moment when the user's eyes are naturally focused at that depth, maintaining imaging stability while achieving accurate depth perception
Solution Approach 2:
The display system incorporates feedback mechanisms that monitor the user's eye position, vergence angle, and accommodation response in real-time. This feedback is used to adjust the timing and positioning of focal plane presentations, ensuring that the multi-focal content remains stable and comfortable for the user while maintaining precise depth cues
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 enhances depth perception by reducing eye strain and providing a larger field of view, ensuring that virtual content is presented at appropriate focal planes, thus improving user comfort and visual stability.
Implementation Method 1
a diffractive optical element (DOE) to receive the light associated with the one or more frames of image data and direct the light to the user's eyes
Implementation Method 2
a waveguide substrate corresponding to a waveguide refractive index
Data Source
AI summary
Disclosed is an improved diffraction structure for 3D display systems. The improved diffraction structure includes an intermediate layer that resides between a waveguide substrate and a top grating surface. The top grating surface comprises a first material that corresponds to a first refractive index value, the underlayer comprises a second material that corresponds to a second refractive index value, and the substrate comprises a third material that corresponds to a third refractive index value. According to additional embodiments, improved approaches are provided to implement deposition of imprint materials onto a substrate, which allow for very precise distribution and deposition of different imprint patterns onto any number of substrate surfaces.