Touch-Sensitive Display Controller Dynamic Scanning Rate Adjustment
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Solution Overview
Problem
Portable electronic devices with touch-sensitive displays face challenges in power conservation while maintaining accurate touch detection, as they typically consume high power during frequent scanning of touch-sensitive displays, especially when no significant input is detected.
Innovation Solution
The method involves applying a reduced number of pulses to scanning electrodes during a low-power condition to conserve power, allowing for touch detection while resuming full-power scanning when a touch is detected or when the touch moves beyond a threshold distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent scanning of touch-sensitive display is performed to detect touches, then touch detection accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic scanning rate adjustment based on system state. The controller varies the scanning rate from frequent scanning during active use to reduced scanning during idle periods, allowing the system to adapt between accuracy and power consumption requirements. This resolves the contradiction by making the scanning frequency flexible rather than fixed.
Solution Approach 2:
The patent changes the scanning rate parameter based on detected touch conditions and system state. When no touch is detected for a threshold period, the scanning rate is reduced to conserve power. When touches are detected or gestures are identified, the scanning rate increases to maintain accuracy. This parameter adjustment directly addresses the power consumption vs. detection accuracy trade-off.
2Use of energy by moving object
If reduced scanning rate is used to conserve power, then power consumption is reduced, but touch detection reliability deteriorates
Solution Approach 1:
The system continuously monitors for touch events and uses this feedback to adjust scanning rate. When touches are detected at reduced scanning rates or when gestures are identified, the system provides feedback to increase scanning rate, ensuring detection reliability is maintained when needed while allowing power savings during idle periods.
Solution Approach 2:
The patent applies partial scanning action during idle periods by using reduced scanning rate that may occasionally miss touches, but compensates by using gesture recognition and touch event feedback to ensure important interactions are not missed. This acceptable level of partial action enables significant power savings while maintaining sufficient reliability for typical use.
3Reliability
If full-power scanning is maintained continuously, then touch detection reliability is maintained, but battery life decreases
Solution Approach 1:
The patent implements periodic scanning at reduced rates during idle periods rather than continuous full-power scanning. The controller periodically checks for touch events and adjusts scanning rate accordingly, allowing the system to maintain adequate detection reliability for typical use while significantly extending battery life through periodic rather than continuous operation.
Solution Approach 2:
The system dynamically adjusts scanning rate based on actual usage conditions. During idle periods with no touch input, the scanning rate is reduced to extend battery life. When touches are detected or gestures are identified, the system dynamically increases scanning rate to maintain reliability, thus balancing battery life and detection reliability across different operational states.
Data Source
AI summary
A method includes applying a first plurality of pulses to scanning electrodes during a first scan to detect touches on a touch-sensitive display, receiving an indication to scan in a reduced power condition, and when in the reduced power condition, applying a second plurality of pulses to scanning electrodes during a second scan to detect touches on the touch-sensitive display, wherein the second plurality of pulses comprises fewer pulses than the first plurality of pulses.