VR Headset Dual-Display Optics for 20/20 Acuity Testing
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Solution Overview
Problem
Consumer-grade VR headsets lack sufficient full frame pixel resolution to accurately measure visual acuity at the 20/20 level, and existing methods for visual acuity testing in VR headsets often suffer from ghosting effects due to weak reflection characteristics of dichroic filters.
Innovation Solution
A modified VR headset with a first display and a smaller second display, along with dichroic filters positioned to pass NIR light from the eye tracker camera and reflect visible light from the second display, combined with pixel data control circuitry to darken the first display during testing, enabling accurate visual acuity measurement up to 20/20 vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard consumer-grade VR headset is used, then device complexity and cost are reduced, but measurement precision of visual acuity deteriorates due to insufficient full frame pixel resolution
Solution Approach 1:
The headset display system is segmented into two separate displays: a first display for general VR content and a second display specifically for visual acuity testing. This segmentation allows each display to be optimized for its specific function, with the second display having sufficient pixel density for 20/20 visual acuity measurement while the first display handles general VR rendering.
Solution Approach 2:
A dichroic filter is introduced as an intermediary optical element that selectively transmits and reflects different wavelengths of light. This filter enables the second display to project test patterns to the user's eye without interfering with the first display's VR content, and allows an eye tracker camera to capture the user's eye image through the same optical path.
2Measurement precision
If a smaller second display with lower pixel count is added to enable visual acuity testing, then measurement precision is improved, but device complexity increases due to additional displays and optical components
Solution Approach 1:
The second display and dichroic filter combination serves multiple functions: displaying visual acuity test patterns to the user, allowing the eye tracker camera to capture eye images, and integrating into the existing VR headset optical path. This multi-functionality reduces the need for separate dedicated components for each function.
Solution Approach 2:
The optical paths for the first display, second display, and eye tracker camera are merged through the dichroic filter. The filter combines these separate optical paths into a unified system where all components share the same physical space and optical pathway, reducing overall system complexity despite adding functional capability.
3Ease of operation
If manual or audible feedback is required for visual acuity testing, then ease of operation deteriorates, but device complexity is reduced by not adding eye tracking components
Solution Approach 1:
The system uses the user's own eye as the feedback mechanism. The eye tracker camera captures the user's eye image, and the dichroic filter allows this image to be viewed by the user or captured for analysis. This self-service approach eliminates the need for separate feedback interfaces while using naturally available biological signals.
Solution Approach 2:
The system implements feedback by capturing the user's eye image through the eye tracker camera and dichroic filter combination. This visual feedback loop allows the system to detect eye movements, fixation, and other ocular responses that provide information about visual acuity without requiring manual or audible feedback from the user.
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 accurate visual acuity testing up to 20/20 vision using a consumer-grade VR headset by minimizing ghosting effects and leveraging the eye tracker camera for hands-free feedback.
Implementation Method 1
a dichroic filter positioned to pass visible light from the first display toward the eye and reflect visible light from the second display toward the eye
Data Source
AI summary
A headset includes a first display, a second display that is smaller than the first display and has lower resolution than the first display, and a dichroic filter positioned to pass visible light from the first display toward the eye and reflect visible light from the second display toward the eye. Pixel data control circuitry is coupled to darken the first display while simultaneously activating the second display to display a pattern for testing visual acuity, responsive to a first visual acuity test selection. Other aspects are also described and claimed.