Proximity Sensing Offset Control for Drift and False Screen Triggers
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Solution Overview
Problem
Proximity sensors in smartphones often inaccurately determine the proximity to objects, leading to incorrect switching of the display screen on or off, which affects battery life and operational accuracy.
Innovation Solution
A method and system that apply an offset to the signal output from a proximity sensor, adjusting for drift by comparing the output signal to a first threshold and an average signal to different thresholds, thereby distinguishing between actual movement and drift, and resetting the measurement when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the proximity sensor uses a simple threshold comparison to determine proximity, then the device complexity is reduced, but the measurement precision deteriorates due to drift and false readings
Solution Approach 1:
The system continuously monitors the proximity sensor output and compares it against dynamically adjusted thresholds. When drift is detected through sustained threshold violations, the system automatically recalibrates the offset and thresholds, creating a closed-loop feedback mechanism that maintains measurement precision without requiring complex hardware
Solution Approach 2:
The system dynamically adjusts the offset parameter and threshold values based on detected drift conditions. By changing these parameters in response to environmental changes or sensor degradation, the system maintains accurate proximity detection without increasing physical complexity
2Measurement precision
If the system applies drift correction by adjusting the offset, then the measurement precision improves, but the device complexity increases due to additional processing requirements
Solution Approach 1:
The proximity sensing system performs its own self-calibration by monitoring its output signals and automatically adjusting its offset and thresholds when drift is detected. This self-service capability eliminates the need for external calibration equipment or complex manual adjustment mechanisms
Solution Approach 2:
The system applies drift correction selectively rather than continuously - only when threshold violations persist for a predetermined time indicating actual drift rather than normal signal variation. This partial action approach maintains precision while minimizing unnecessary processing complexity
3Reliability
If the system requires a predetermined period of time for drift identification, then the reliability improves by avoiding false drift detection, but the loss of time increases during proximity sensing operations
Solution Approach 1:
The system dynamically adjusts the time threshold for drift identification based on the application context and signal characteristics. The predetermined time period is optimized to be sufficient for reliable drift detection while minimizing impact on normal proximity sensing response, allowing the system to adapt between reliability and speed requirements
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 effectively identifies drift while preventing incorrect identification of movement towards or away from an object as drift, ensuring accurate switching of the display screen and prolonging battery life.
Implementation Method 1
emitting light from an emitter and detecting reflected light
Data Source
AI summary
A method of proximity sensing which comprises emitting light from an emitter and detecting reflected light, applying an offset to the detected reflected light to provide an output signal indicative of proximity, determining an average signal of the output signal; determining whether drift has occurred by comparing the output signal to a first threshold and comparing the average signal to a different threshold, and adjusting the offset if drift is identified.