Optical Device Testing via Eye Motion Box Image Capture
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Solution Overview
Problem
There is a need for specialized testing of optical devices, particularly in augmented reality systems, to evaluate performance at both the component and integrated unit levels, focusing on issues like smears, white lines, and black lines due to the combination of real and synthetic images.
Innovation Solution
A method involving capturing images at specific locations relative to an optical device's lightguide, projecting test patterns, and deriving metrics from these images to assess performance, including the use of diffractive and reflective optical components to expand and direct light, and analyzing brightness levels and cross-sections to detect smearing and white stripes phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If images are captured at multiple capture locations within the eye motion box, then measurement precision for detecting smears, white lines, and black lines is improved, but device complexity and testing time increase
Solution Approach 1:
The testing process is segmented into multiple discrete capture locations within the eye motion box, with each location capturing specific visual artifacts (smears, white lines, black lines). By dividing the testing space into distinct measurement zones, the system achieves comprehensive coverage and high detection precision without requiring a single overly complex measurement apparatus.
Solution Approach 2:
The testing approach transitions from single-point measurement to multi-location spatial measurement within the eye motion box. By adding the spatial dimension of multiple capture locations, the system comprehensively detects visual artifacts across different viewing positions, improving measurement precision while maintaining manageable system complexity through standardized measurement procedures at each location.
2Measurement precision
If multiple capture locations are used for image capture, then detection accuracy of optical defects is improved, but loss of time in the testing process increases
Solution Approach 1:
The system pre-defines specific capture locations and measurement parameters before actual testing begins. By establishing the eye motion box boundaries and identifying key capture positions in advance, the testing process efficiently captures critical visual artifacts without unnecessary measurements, reducing testing time while maintaining high detection accuracy.
Solution Approach 2:
The testing method focuses on capturing images at strategically selected key locations within the eye motion box rather than performing continuous or exhaustive measurements. By skipping non-critical measurement points and concentrating on locations most likely to reveal smears, white lines, and black lines, the system achieves high detection accuracy with reduced testing duration.
3Area of stationary object
If diffractive and reflective optical components are used to expand light, then the eye motion box area is increased, but device complexity increases
Solution Approach 1:
The optical system merges diffractive optical components and reflective optical components into an integrated light expansion system. By combining these different optical mechanisms, the system achieves broader eye motion box coverage and improved light distribution without requiring separate independent systems, thereby managing device complexity while expanding the functional area.
Solution Approach 2:
The optical components are designed to perform multiple functions: diffractive components expand light in one direction while reflective components expand light in another direction, and both work together to illuminate the entire eye motion box. This multi-functionality allows a single integrated optical system to achieve comprehensive area coverage, reducing the need for additional specialized components.
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
This method effectively evaluates the optical device's performance by capturing and analyzing images at various locations, providing detailed metrics on smearing and white stripes, ensuring the quality and accuracy of the optical output in augmented reality systems.
Implementation Method 1
a first pair of external surfaces parallel to each other for guiding light by internal reflection
Implementation Method 2
a first diffractive optical component configured for directing said coupled-in light in a first direction of expansion within said one lightguide, thereby generating first expanded light; said second diffractive optical component configured for expanding said first expanded light in said one lightguide in a second direction of expansion
Implementation Method 3
a reflective optical component including a sequence of a plurality of partially reflective, mutually parallel surfaces; and said reflective optical component configured for out-coupling said second expanded light in a third direction as said coupled-out light
Data Source
AI summary
At various positions in an eye motion box (EMB) an output image from an optical device can be captured and analyzed for detection and evaluation of image propagation via the optical device. Optical testing along a specific axis can evaluate optical engine transfer function uniformity across facet's active area, detect the existence and degree of “smearing” of a projected image from an optical device, and detect the existence and degree of a “white stripes” (WS) phenomenon related to scattering and diffraction in the wedge-to-LOE interface. A variety of metrics can be derived for quality control and feedback into the production system, and for disposition of the optical devices.