Thermal Convection User Detection for Low Power
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Solution Overview
Problem
Existing user detection sensors for electronic devices consume high power and may not effectively detect humans within a limited range or direction, raising concerns about privacy and efficiency.
Innovation Solution
A user detection system utilizing a sensor unit with a heater and temperature sensor elements to detect airflow in a user space, calculating temperature differences to determine the presence of a human, distinguishing between human-generated airflow and noise, and adjusting for sensor orientation and tilt to enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active-type user detection sensors (infrared, ultrasonic, light) or camera are used to detect human presence, then user detection capability is achieved, but power consumption increases significantly
Solution Approach 1:
The patent replaces active sensing systems (infrared, ultrasonic, optical) with a passive thermal convection-based detection system. A heater element creates a thermal field that interacts with air flow, and temperature sensor resistive elements detect the resulting temperature changes caused by human presence, eliminating the need for active emission and detection of electromagnetic or acoustic waves
Solution Approach 2:
The system changes the detection parameter from active signal reflection (infrared, ultrasonic, optical) to passive thermal convection patterns. By monitoring temperature differences caused by air flow displacement around a heater element, the system detects human presence through thermal field interactions rather than electromagnetic or acoustic wave reflections
2Measurement precision
If conventional user detection sensors are used, then detection is possible, but detection range and direction are limited
Solution Approach 1:
The thermal convection-based sensor unit can detect human presence from multiple directions simultaneously due to the three-dimensional nature of air flow patterns around the heater element. The system processes temperature differences from multiple sensor elements arranged in specific configurations to determine both presence and directional information, providing omnidirectional detection capability
Solution Approach 2:
The patent transitions from two-dimensional planar detection to three-dimensional volumetric detection by utilizing air flow patterns in three-dimensional space. The sensor unit detects temperature variations caused by convection currents that originate from human body heat and interact with the heater element from various spatial dimensions, enabling detection regardless of the user's approach direction
3Ease of operation
If user detection sensors are used to enable device operation, then user convenience is improved, but false detection of environmental airflows reduces accuracy
Solution Approach 1:
The system continuously monitors temperature differences between multiple sensor elements and compares the pattern against expected human-generated convection patterns. By analyzing the temporal and spatial characteristics of temperature changes, the system distinguishes between human presence and environmental air flow, providing feedback-based filtering to eliminate false detections
Solution Approach 2:
The sensor element arrangement and heater element configuration create an asymmetric thermal field that responds differently to human presence versus environmental air flow. Human-generated convection patterns produce characteristic asymmetric temperature distributions that differ from symmetric environmental air flow patterns, enabling discrimination through pattern recognition
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 system efficiently detects human presence with reduced power consumption, offering wide-range detection capabilities and improved accuracy by differentiating between human and environmental airflows, thus enabling effective operation of electronic devices.
Implementation Method 1
the flow sensor includes a heater element and a pair of temperature sensor resistive elements disposed on both sides of the heater element
Implementation Method 2
temperature sensor resistive elements disposed on both sides of the heater element
Implementation Method 3
calculating temperature differences to determine the presence of a human
Data Source
AI summary
A user detection apparatus includes a processor for an information handling device and a memory that stores code executable by the processor. The code is executable by the processor to detect a user in a user space that is proximate to the information handling device in response to an airflow being detected in the user space and, in response to detecting the user, resume or begin operations in the information handling device.