Directed EM Emitter and Reflector Layout for Low-Latency AR Tracking
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Solution Overview
Problem
Existing augmented reality systems face challenges in accurately tracking the position and orientation of mobile components, such as head-mounted devices and hand-held controllers, due to bulky electromagnetic emitters and high latency issues in optical tracking methods, which hinder the delivery of realistic AR experiences.
Innovation Solution
The use of compact electromagnetic emitters and sensors, integrated with reflectors to enhance electromagnetic field intensity and directionality, combined with IMU-based pose tracking, allows for high-precision localization of mobile components with reduced power consumption and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electromagnetic emitters are used for tracking, then tracking functionality is achieved, but the emitter size and power consumption increase
Solution Approach 1:
The patent applies asymmetry by using a non-spherical emitter geometry (such as a planar or elongated shape) that creates an asymmetric electromagnetic field pattern. This asymmetric field allows the sensor to determine not only position but also orientation (roll, pitch, yaw) of the emitter, achieving 6-DOF tracking. The asymmetric shape enables directionality in field emission, improving tracking precision while keeping the emitter compact.
Solution Approach 2:
The patent transitions from spherical symmetric emitters to planar or elongated emitters that emit fields with directional characteristics in specific dimensions. By orienting the emitter plane at specific angles (e.g., 45 degrees) relative to the sensor, the system extracts orientation information from the spatial distribution of the electromagnetic field, adding rotational dimensionality to the tracking capability without significantly increasing emitter volume.
2Use of energy by moving object
If transmit power is reduced to decrease power consumption, then power efficiency improves, but electromagnetic field strength decreases
Solution Approach 1:
The asymmetric emitter geometry concentrates the electromagnetic field energy in specific directional lobes rather than distributing it uniformly in all directions. This directional concentration allows the sensor to detect stronger field signals at particular orientations and positions, enabling reduced transmit power while maintaining detection sensitivity. The asymmetric pattern creates regions of enhanced field strength that improve signal-to-noise ratio.
Solution Approach 2:
The emitter is designed to produce locally enhanced electromagnetic field regions (lobes) in specific spatial directions where the sensor is expected to be positioned. By concentrating energy in these local regions rather than distributing it uniformly, the system achieves stronger field strength at critical detection points while reducing overall power consumption. The local quality of the field is optimized for the specific tracking geometry.
3Measurement precision
If optical tracking methods are used, then tracking is achieved, but latency increases
Solution Approach 1:
The patent replaces optical tracking methods (which require cameras, image processing, and computational matching) with electromagnetic field-based tracking. The electromagnetic approach uses direct field sensing that provides immediate position and orientation data without the processing delays inherent in optical systems. The sensor detects electromagnetic field characteristics (strength, direction, phase) that directly encode spatial information, enabling real-time tracking with minimal latency.
4Object-affected harmful factors
If emitter power is reduced to minimize distortions, then EM distortion decreases, but field strength decreases
Solution Approach 1:
The asymmetric emitter design creates a field pattern with distinct directional lobes that maintain sufficient strength for accurate sensing even at lower transmit powers. The asymmetric geometry ensures that the field distribution contains enough spatial information for precise tracking while operating at reduced power levels that minimize distortion effects from metallic objects and other environmental factors.
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 enables accurate, low-latency tracking of head poses and user interactions in AR systems, enhancing the realism of virtual content display and user interaction with reduced power consumption and emitter size.
Implementation Method 1
an electromagnetic field emitter configured to emit a known electromagnetic field that extends through a coordinate space
Implementation Method 2
an electromagnetic sensor configured to detect a behavior of the known electromagnetic field
Data Source
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AI summary
A head mounted augmented reality display system comprising a hand held controller (306) comprising an emitter housing including a first electromagnetic reflector (820) including three first reflective elements (812; 814; 816) forming a first corner vertex of a first cube, wherein the first electromagnetic reflector defines a first coordinate space and the first corner vertex of the first cube lies at the origin of the first coordinate space; and an electromagnetic emitter (510) configured to produce an electromagnetic field, wherein the electromagnetic emitter is positioned along a line directed at point (1,1,1) in the first coordinate space; and a headset (301) comprising a right temple; a left temple; and a sensor housing (1075) mounted on at least one of the right temple or left temple, the sensor housing comprising an electromagnetic sensor (1070); and a second electromagnetic reflector (1072) including three second reflective elements forming a second corner vertex of a second cube.