Pancake Lens PSOG Eye Tracking for Low-Power VR/AR HMDs
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Solution Overview
Problem
Existing eye tracking systems in VR/AR head-mounted displays face challenges such as high cost, complexity in assembly, weight, heat emission, high energy consumption, and limited space due to the use of IR cameras and mirrors, which are not suitable for mobile, standalone HMD devices.
Innovation Solution
A photosensor oculography (PSOG) system using pancake lenses and micro-OLED displays, combined with temperature compensation and head movement detection, to provide accurate gaze tracking with reduced power consumption and simplified assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If IR cameras and mirrors are used for eye tracking, then tracking accuracy is improved, but device weight and complexity increase
Solution Approach 1:
The patent extracts the eye tracking function from the traditional camera-mirror system and implements it using a simplified photosensor array that directly detects eye position without requiring mirrors or complex optical paths, thereby reducing weight while maintaining tracking capability
Solution Approach 2:
The patent replaces the mechanical/optical system (IR cameras and mirrors) with a photosensor-based detection system that uses light-emitting elements and photosensors to track eye position, eliminating the need for heavy mirror assemblies while achieving comparable or superior tracking accuracy
2Measurement precision
If IR cameras and mirrors are used for eye tracking, then tracking accuracy is improved, but device complexity increases
Solution Approach 1:
The patent removes the mirror component and complex optical routing from the eye tracking system, using instead a direct photosensor array configuration that can be integrated into the display structure, significantly simplifying assembly while maintaining tracking precision
Solution Approach 2:
The patent merges the eye tracking functionality with the display structure by integrating photosensors and light-emitting elements into the existing display housing and optical path, eliminating separate mirror assemblies and reducing overall system complexity
3Measurement precision
If camera-based eye tracking is implemented, then gaze detection capability is improved, but space requirements increase
Solution Approach 1:
The patent transitions from a 3D camera-based detection approach to a 2D photosensor array that detects eye position through light intensity variations, enabling accurate gaze detection in a planar configuration that fits within the thin profile of pancake lens HMDs
4Measurement precision
If traditional eye tracking systems are used, then tracking performance is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic or pulsed operation of the light-emitting elements and photosensor detection, allowing the system to achieve accurate tracking performance while consuming significantly less power compared to continuous operation of IR cameras and associated processing systems
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 PSOG system achieves accurate gaze tracking with low power consumption, reduced weight, and simplified assembly, enhancing user experience and usability in VR/AR devices by enabling features like foveated rendering and intuitive navigation.
Implementation Method 1
a light source (26) that is configured to illuminate an area of a patient's eye (32), a plurality of photosensors (28) that are configured to receive reflection from different (possibly overlapping) parts of the illuminated patient's eye (32)
Data Source
AI summary
A virtual reality (VR) wearable assembly is described herein. The VR wearable assembly includes a wearable frame adapted to be worn over a patient's eyes and a pair of photosensor oculography (PSOG) assemblies mounted to the wearable frame such that each PSOG assembly is positioned adjacent a corresponding eye of the patient. Each PSOG assembly includes a display housing having an inner surface defining an interior cavity extending between a first end and second end, a micro-OLED display coupled to the display housing and positioned within the interior cavity adjacent the second end of the display housing, an eye tracking assembly coupled to the display housing and positioned adjacent the first end of the display housing, and a pancake lens mounted to the display housing and positioned within the interior cavity between the eye tracking assembly and the micro-OLED display.