Eyepiece Edge Configurations for HMD Artifact Reduction
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Solution Overview
Problem
Conventional optics in head-mounted displays (HMDs) often generate artifacts such as 'streaking' in computer-generated images (CGI), leading to gaps and redundant portions, which can degrade the image quality perceived by the user.
Innovation Solution
The use of an eyepiece with reflection reducing features on its edges, such as beveled or chamfered surfaces and darkening elements, to minimize total internal reflection and reduce unwanted reflections of CGI light, thereby improving image integrity by preventing light from being reflected back into the eyepiece and ensuring accurate image presentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optics are used in HMDs, then the structure is simple and easy to manufacture, but artifacts such as streaking are generated in the CGI
Solution Approach 1:
The patent applies local quality by adding reflection reducing features specifically at the edges of the eyepiece where total internal reflection occurs, rather than modifying the entire optical system. The beveled or chamfered edges are localized modifications that prevent artifacts without requiring complete redesign of the optics
Solution Approach 2:
The beveled or chamfered edges act as intermediary structures that modify the path of reflected light. These edge features serve as mediators between the CGI light source and the user's eye, redirecting potentially harmful reflections away from the optical path while maintaining the overall simple optical structure
2Manufacturing precision
If the eyepiece edges are modified with beveled or chamfered surfaces, then total internal reflection is reduced and artifacts are minimized, but the manufacturing process becomes more complex
Solution Approach 1:
The patent changes the geometric parameters of the eyepiece edges by introducing beveled or chamfered surfaces with specific angles. This parameter modification alters the reflection characteristics at the edges, reducing total internal reflection and minimizing artifacts while maintaining manufacturability through standard machining operations
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 implementation of reflection reducing features on the edges of the eyepiece effectively minimizes artifacts in the images presented to the user, enhancing the quality of the superimposed augmented reality by ensuring that CGI light is directed correctly and reducing gaps or redundant portions.
Implementation Method 1
The edges of the eyepiece are configured to reduce reflection of CGI light back into the eyepiece. The configuration of the edges may reduce total internal reflection of the CGI light
Implementation Method 2
darkening elements, to minimize total internal reflection and reduce unwanted reflections of CGI light
Data Source
AI summary
An eyepiece for a head mounted display (“HMD”) includes a first end for receiving computer generated image (“CGI”) light and a second end disposed opposite the first end. The eyepiece also includes an image directing element to direct the CGI light out of the eyepiece in an eye-ward direction. The image directing element is disposed between the first end and the second end. At least one edge running between the first end and the second end is configured to reduce reflection of the CGI light back into the eyepiece.