AR Waveguide Metrology for Alignment and Light Uniformity
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Solution Overview
Problem
Conventional near-eye displays suffer from low optical efficiency and require complex test equipment and procedures for alignment and uniformity measurements, leading to inefficient data capture and processing.
Innovation Solution
A system utilizing a display light engine and optical power meter to characterize optical waveguides, enabling precise alignment and optimization of light extraction uniformity by measuring light emissions from pixel groups, reducing the need for complex test equipment and procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional test equipment and procedures are used for alignment and uniformity measurements, then measurement capability is provided, but device complexity and data capture time increase
Solution Approach 1:
The patent uses a camera to capture images of the display light engine, creating a visual copy that can be analyzed for alignment and uniformity measurements. This replaces complex optical measurement equipment with a simpler imaging system that captures the light distribution pattern, enabling measurement without sophisticated test apparatus.
Solution Approach 2:
The patent replaces mechanical/optical measurement systems with a digital imaging and computational approach. Instead of using specialized optical sensors and mechanical alignment tools, the system uses a camera to capture images and processes them computationally to determine alignment and uniformity, significantly simplifying the test equipment.
2Measurement precision
If conventional test procedures are used, then alignment measurements can be performed, but data capture and processing time increase
Solution Approach 1:
The patent employs frame-by-frame analysis of video footage captured at standard frame rates (e.g., 30 or 60 fps). By utilizing the periodic nature of video frames, the system can capture alignment information continuously without requiring specialized high-speed measurement equipment, reducing both time and complexity.
Solution Approach 2:
The system creates a digital copy of the light engine output through camera imaging, allowing repeated analysis of the same captured data without requiring additional measurement time. The image capture freezes the light distribution pattern, enabling thorough computational analysis without extending data capture duration.
3Measurement precision
If complex test equipment is used for optical characterization, then measurement accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The system uses the display light engine itself as the light source for measurement, eliminating the need for external optical equipment. The light engine illuminates itself and the waveguide during normal operation, and the camera captures this self-emitted light, making the measurement process as simple as operating the display in normal mode.
Solution Approach 2:
The camera serves multiple functions: it captures images for alignment measurement, uniformity analysis, and optical characterization all in one device. This universal approach replaces multiple specialized measurement instruments with a single consumer-grade camera, simplifying operation while maintaining measurement capability.
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 approach significantly reduces data capture and processing time while enhancing the optical efficiency and uniformity of light output, improving the overall throughput of the test system.
Implementation Method 1
an optical waveguide system including a light injection surface, a light extraction surface, and a substrate therebetween
Data Source
AI summary
Techniques for augmented reality waveguide and display light engine metrology are described. In an example, a computer system causes a display light engine to emit first light from a first group of pixels of the display light engine. The computer system determines a first measurement value associated with the first light after the first light is extracted from an optical waveguide. The computer system causes the display light engine to emit second light from a second group of pixels of the display light engine. The second group is different from the first group. The computer system determines a second measurement value associated with the second light after the second light is extracted from the optical waveguide. The computer system generates, based on the first measurement value and the second measurement value, a metrology measurement indicating a property of the optical waveguide.