Touch Driver Frame Frequency Control for Biometric Sensing
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Solution Overview
Problem
Capacitance type touch panels face challenges in precisely measuring biometric information due to the small change in mutual capacitance associated with biometric changes.
Innovation Solution
The display apparatus is designed to drive a touch panel in both normal and biometric information measurement modes, with specific adjustments such as altering frame frequencies and transmission signal voltages to enhance biometric measurement precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the touch panel operates in normal mode with standard frame frequency, then the display updates smoothly and responsiveness is maintained, but the biometric measurement precision deteriorates due to insufficient measurement time and increased noise
Solution Approach 1:
The system dynamically switches between normal mode and biometric measurement mode, adjusting the frame frequency based on the operational requirement. In biometric measurement mode, the frame frequency is reduced to allow sufficient measurement time, while in normal mode, the frame frequency returns to standard levels for smooth display updates.
Solution Approach 2:
The frame frequency parameter is changed based on the operating mode. When entering biometric measurement mode, the frame frequency is lowered to improve measurement precision. The system monitors the measurement completion status and adjusts the frame frequency accordingly, transitioning back to normal frame frequency once measurement is complete.
2Measurement precision
If the frame frequency is reduced to improve biometric measurement precision, then the measurement accuracy improves, but the time required for biometric measurement increases
Solution Approach 1:
The system performs preliminary actions by reducing the frame frequency before biometric measurement begins. This preliminary frame rate adjustment ensures that subsequent measurement operations can proceed with sufficient time for accurate reading, avoiding the need for post-measurement time compensation.
Solution Approach 2:
The biometric measurement process continues uninterrupted by maintaining a reduced frame frequency throughout the measurement period. The system keeps the frame frequency lowered from the start of measurement until the measurement is complete, ensuring continuous accurate data collection without interruptions that would extend measurement time.
3Measurement precision
If the transmission signal voltage is increased to enhance biometric detection sensitivity, then the measurement precision improves, but the energy consumption increases
Solution Approach 1:
The transmission signal is applied periodically rather than continuously. The system activates the transmission signal during specific measurement periods when biometric measurement is required, and deactivates it during normal display operation. This periodic activation reduces overall energy consumption while maintaining measurement precision when needed.
Solution Approach 2:
The transmission signal voltage parameter is changed based on the operating mode. In biometric measurement mode, the voltage is increased to enhance detection sensitivity. In normal mode, the voltage returns to standard levels, reducing energy consumption during display operations.
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 allows for more precise measurement of biometric information by reducing the number of frame periods required and minimizing noise generation, thereby improving sensing quality and reducing energy usage.
Implementation Method 1
the capacitance type touch panel for measuring a change in mutual capacitance
Data Source
AI summary
A display apparatus includes a touch panel including a plurality of electrodes and a touch driver. The touch panel includes first electrodes extending in a first direction and second electrodes extending in a second direction and overlapping the first electrodes. The touch driver is configured to drive the touch panel in a normal mode and a biometric information measurement mode. The touch driver is configured to sequentially apply a transmission signal to the first electrodes by shifting the transmission signal at each group of N electrodes (where N is a positive integer) in the normal mode, and to sequentially apply the transmission signal to the first electrodes by shifting the transmission signal at each group of Q electrodes (where Q is a positive integer greater than N) in the biometric information measurement mode.