Micro-sized Angular Light Sensor for Eye-tracking
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Solution Overview
Problem
Existing angular light sensors are bulky, power inefficient, and have slow processing times, limiting their applications, particularly in augmented and virtual reality where fast, low-power, and compact eye-tracking solutions are needed.
Innovation Solution
The development of micro-sized angular light sensors with high angular resolution, large detection range, and out-of-axis sensitivity, integrated into near-eye optical elements of head-mounted devices, using a source-sensor pair with photodiodes and tilted light barriers, and potentially incorporating Talbot sensors for non-camera based eye-tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If existing angular light sensors are used, then they can perform light detection, but they are bulky and have large device size
Solution Approach 1:
The sensor is divided into multiple photodetector elements arranged in specific patterns (e.g., quadrants, rings, or linear arrays). Each photodetector measures light intensity from a specific angular direction, and the combined signals from multiple segments enable precise angular resolution in a compact form factor.
Solution Approach 2:
The patent transitions from single-dimensional light detection to multi-dimensional detection by arranging photodetectors in two-dimensional patterns (quadrants, rings, or grids). This spatial arrangement allows the compact sensor to capture angular information in multiple directions simultaneously, achieving high angular resolution without increasing overall sensor volume.
2Use of energy by moving object
If existing angular light sensors are used, then they can perform light detection, but they consume excessive power
Solution Approach 1:
The sensor employs periodic or pulsed illumination rather than continuous illumination, allowing the photodetectors to be activated only when measurement is needed. This reduces average power consumption while maintaining the ability to achieve high angular resolution when the sensor is actively measuring.
Solution Approach 2:
The sensor design allows the photodetector array to self-determine angular position through differential signal processing of light intensity patterns across the array elements. This eliminates the need for additional active components or complex processing circuits, reducing overall power consumption while maintaining measurement precision.
3Productivity
If existing angular light sensors are used, then they can perform light detection, but they have slow processing times
Solution Approach 1:
The patent replaces mechanical scanning or moving parts with a static photodetector array that simultaneously captures angular information from multiple directions. This optical-electrical direct conversion eliminates mechanical delays and enables fast processing of angular data while maintaining high angular resolution through the spatial arrangement of photodetectors.
Solution Approach 2:
The photodetector array is pre-configured in specific geometric patterns (quadrants, rings, or grids) that correspond to different angular sectors. This preliminary spatial arrangement allows the sensor to directly calculate angular position from the detected light intensity distribution without requiring complex real-time processing, thereby improving processing speed while maintaining precision.
4Volume of moving object
If micro-sized sensors are used, then device size is reduced, but angular resolution may be compromised
Solution Approach 1:
The patent concentrates photodetector elements in specific local regions or patterns (such as quadrants, rings, or linear arrays) rather than uniformly distributing them. This local concentration strategy allows compact micro-sized sensors to achieve high angular resolution in specific angular directions by optimizing the spatial arrangement of photodetectors in those critical regions.
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
These sensors enable fast, low-power, and compact eye-tracking with high accuracy, suitable for augmented and virtual reality applications, capable of detecting fixational eye movements and providing meaningful cognitive and attentional information.
Implementation Method 1
a first photodiode, a second photodiode, and a tilted light barrier
Implementation Method 2
a tilted light barrier, the first photodiode and the second photodiode are separated by the tilted light barrier
Data Source
AI summary
Angular sensors that may be used in eye-tracking systems are disclosed. An eye-tracking system may include a plurality of light sources to emit illumination light and a plurality of angular light sensors to receive returning light that is the illumination light reflecting from an eyebox region. The angular light sensors may output angular signals representing an angle of incidence of the returning light.