Multi-Depth Exit Pupil Expander With Segmented Optical Power
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Solution Overview
Problem
Challenges exist in producing augmented reality technologies that facilitate a comfortable, natural-feeling, rich presentation of virtual image elements amidst real-world imagery.
Innovation Solution
A head-mounted display device with a light projector and an eyepiece featuring a light guiding layer and focusing optical elements that direct light to present virtual images at different focal distances, utilizing diffractive or holographic optical elements and polarization modulators to manage image presentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single focal distance is used in the eyepiece, then the optical system is simpler, but the ability to present virtual images at multiple depths is lost
Solution Approach 1:
The eyepiece is divided into multiple regions with different optical powers. The first region has a first optical power for presenting virtual images at a first focal distance, while the second region has a second optical power for presenting virtual images at a second focal distance. This segmentation allows the single eyepiece to present multiple depth planes without requiring multiple separate optical systems.
Solution Approach 2:
Different regions of the eyepiece are assigned different local optical properties. The first region and second region have distinct optical powers tailored to their specific functions of presenting virtual images at different focal distances. This local differentiation enables multi-depth presentation while maintaining a unified eyepiece structure.
2Adaptability or versatility
If multiple optical elements are added to achieve multi-depth focus, then depth presentation improves, but manufacturing precision requirements increase
Solution Approach 1:
Multiple optical elements with different optical powers are merged into a single integrated eyepiece structure. The first and second regions with different optical powers are combined in one component, reducing the number of separate elements that need to be aligned and manufactured independently, thereby lowering overall manufacturing precision requirements.
Solution Approach 2:
The eyepiece utilizes composite optical structures where different regions with distinct optical properties are integrated into a unified component. This composite approach allows for multi-depth focal presentation while managing manufacturing complexity through integrated design rather than assembly of multiple precision elements.
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
Enhances the presentation of virtual images at varying focal distances, improving the immersion and clarity of augmented reality experiences.
Implementation Method 1
The first focusing optical element comprises a first region having a first optical power arranged between a first region of the light guiding layer and the user side of the eyepiece, and a second region having a second optical power different from the first optical power
Implementation Method 2
utilizing diffractive or holographic optical elements and polarization modulators to manage image presentation
Implementation Method 3
utilizing diffractive or holographic optical elements and polarization modulators to manage image presentation
Data Source
AI summary
An example head-mounted display device includes a light projector and an eyepiece. The eyepiece includes a light guiding layer and a first focusing optical element. The first focusing optical element includes a first region having a first optical power, and a second region having a second optical power different from the first optical power. The light guiding layer is configured to: i) receive light from the light projector, ii) direct at least a first portion of the light to a user's eye through the first region to present a first virtual image to the user at a first focal distance, and iii) direct at least a second portion of the light to the user's eye through the second region to present a second virtual image to the user at a second focal distance.