Proximity Sensor Threshold Mapping for Dust-Tolerant Detection
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Solution Overview
Problem
Proximity sensors in electronic devices, such as mobile phones, often malfunction due to dust or oil accumulation, leading to persistent detection of a 'NEAR' signal and failure to detect 'FAR' signals, causing unintended backlight and touchscreen deactivation during calls.
Innovation Solution
A method of dynamically adjusting threshold values for proximity sensors using a mapping table to set base proximity values and update high and low thresholds based on detected values, ensuring accurate proximity detection and preventing false interrupts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed threshold values are used for proximity detection, then the device structure remains simple, but dust or oil accumulation causes persistent false NEAR signals and inability to detect FAR signals
Solution Approach 1:
The patent applies dynamics by making the threshold values adjustable rather than fixed. The system dynamically changes threshold values based on detected proximity readings, allowing the detection parameters to adapt over time. This resolves the contradiction by enabling the thresholds to evolve with dust accumulation while maintaining a relatively simple overall device structure.
Solution Approach 2:
The patent directly implements parameter changes by modifying the threshold values used for proximity detection. When dust or oil accumulates on the sensor, the system detects the changed proximity readings and adjusts the threshold parameters accordingly, allowing accurate FAR/NEAR detection to be maintained despite environmental contamination.
2Measurement precision
If threshold values are adjusted to accommodate dust accumulation, then detection accuracy improves, but the system requires complex mapping tables and dynamic adjustment mechanisms
Solution Approach 1:
The patent applies preliminary action by pre-defining multiple ranges of threshold values and their corresponding mappings before actual use. The mapping table is prepared in advance with different threshold sets for different dust accumulation conditions. When dust accumulates, the system simply looks up the appropriate pre-prepared thresholds rather than calculating new ones, reducing the complexity of real-time adjustments.
3Ease of operation
If the proximity sensor continuously monitors with fixed thresholds, then the system remains simple to operate, but dust accumulation causes backlight and touchscreen to be incorrectly deactivated
Solution Approach 1:
The patent implements feedback by continuously monitoring proximity readings and using this information to adjust threshold values. The system reads proximity data, compares it against current thresholds, and when dust accumulation is detected (indicated by consistently high readings), it triggers threshold reconfiguration. This feedback loop maintains reliable operation during calls while keeping the system easy to operate, as the adjustments happen automatically based on sensor feedback.
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 mitigates the impact of dust and oil accumulation by dynamically adjusting threshold values, ensuring correct proximity detection and preventing unnecessary backlight and touchscreen deactivation during calls.
Implementation Method 1
When the proximity sensor detects any object in proximity via IR LED reflection strength
Data Source
AI summary
A method of dynamically adjusting threshold values for an electronic device is disclosed. The method comprises setting the base proximity value to a maximum proximity value; polling a detected proximity value; determining a first range where the detected proximity value falls according to a mapping table; setting the base proximity value to a largest value of the first range; determining a high threshold value and a low threshold value according to the base proximity value; and resetting the base proximity value to a default value when the proximity function is disabled.