IRTOF Sensor Frequency Modulation for Presence Detection
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Solution Overview
Problem
Infrared time of flight (IRTOF) sensors in information handling systems face challenges with false user absence detections due to environmental interference, leading to disruptions in system use and reduced accuracy over time.
Innovation Solution
The system applies infrared frequency calibration information to adjust IRTOF sensor operations, using frequency domain modulation and validation through a proximity detection application to improve user presence and absence detection accuracy by monitoring and adapting to environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If IRTOF sensor uses rapid and highly sensitive detection of presence and absence, then response time to user absence and presence is improved, but false user absence detections occur due to environmental interference
Solution Approach 1:
The patent applies frequency domain modulation to the infrared sensing signal, changing the temporal parameter of detection from continuous to modulated frequency domains. This allows the sensor to distinguish between ambient infrared interference and actual user presence/absence by detecting modulated frequency components, thereby maintaining rapid response while reducing false detections caused by environmental interference.
2Measurement precision
If IRTOF sensor operates in high infrared interference environments, then detection range and accuracy are maintained, but calibration becomes more complex and detection performance degrades
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the infrared detection signal quality and dynamically adjusts the modulation frequency or depth based on detected interference levels. This closed-loop approach automatically compensates for environmental changes without requiring manual recalibration, maintaining detection accuracy while simplifying the calibration process in high interference environments.
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 enhances the reliability and timeliness of user presence and absence indications, reducing the risk of end user disruptions and maintaining accurate detection despite environmental changes.
Implementation Method 1
IRTOF sensors illuminate an area where an end user is expected, such as in front of a display that presents visual images, with an infrared light source and detects objects based upon time of flight of infrared reflections detected at the sensor
Implementation Method 2
illuminate an area where an end user is expected with an infrared light source and detects objects based upon time of flight of infrared reflections
Implementation Method 3
Infrared frequency calibration information is applied by an information handling system to adjust IRTOF sensor operations. The proximity detection application validates IRTOF sensor results by reference to calibration information... applies frequency domain modulation of infrared sensing
Data Source
AI summary
An information handling system manages operation of an infrared time of flight sensor to provide accurate and timely user presence and absence detection through modulation in the frequency domain of infrared light, such as by hopping or multiplexing through plural infrared frequencies sensed by the time of flight sensor. An application of the information handling system retrieves calibration information from the infrared time of flight sensor and applies the calibration information to select the plural infrared frequencies. If one or more predetermined conditions, such as a change in ambient light characteristics, the application commands an update of the calibration information to enhance user presence and absence detection.