Touch Sensing Device Proximity Detection Circuit
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Solution Overview
Problem
Capacitive touchscreens face challenges in precisely detecting proximity touches without direct contact, requiring advanced techniques to sense capacitance changes over wide areas and minute variations.
Innovation Solution
A touch sensing device with a driving circuit, buffer circuit, and integration circuit that apply specific clock signals and operational amplifiers to generate and integrate voltage signals, allowing for both normal touch and proximity touch detection by switching configurations to optimize capacitance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitance detection methods are used, then direct touches can be detected, but proximity touches cannot be precisely detected
Solution Approach 1:
The patent implements dynamic switching between normal touch mode and proximity touch mode through control signals. The buffer circuit changes its operational configuration based on the detected touch type, enabling adaptive detection for different touch scenarios while maintaining circuit reusability
Solution Approach 2:
The same buffer circuit and integration circuit are used for both normal touch detection and proximity touch detection. By switching the buffer circuit's operational mode, the system achieves multi-functionality without requiring separate dedicated circuits for each detection type
2Adaptability or versatility
If capacitance sensing is extended to wide areas, then proximity touch detection capability is improved, but detection of minute capacitance changes becomes more difficult
Solution Approach 1:
The integration circuit accumulates voltage signals from the buffer circuit over multiple cycles, effectively amplifying weak capacitance change signals. This feedback-based integration process enhances the detection capability for minute capacitance variations caused by proximity touches
Solution Approach 2:
The system applies periodic driving signals to the electrode and samples the capacitance changes at specific phases. By using periodic driving and sampling, the system enhances signal-to-noise ratio for detecting subtle capacitance variations associated with proximity touches
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
Enables precise detection of proximity touches by effectively generating and integrating voltage signals, enhancing the capability to sense capacitance changes even when touches are not made directly to the touch panel, improving user interaction with capacitive touchscreens.
Implementation Method 1
a buffer circuit converting capacitance of the node capacitor into a voltage signal
Implementation Method 2
a buffer capacitor being charged and discharged depending on an output voltage from the buffer circuit
Data Source
AI summary
There are provided a touch sensing device and a touchscreen device. The touch sensing device includes: a driving circuit applying a driving signal having a predetermined first period to a node capacitor; a buffer circuit converting capacitance of the node capacitor into a voltage signal; a buffer capacitor being charged and discharged depending on an output voltage from the buffer circuit; and an integration circuit integrating voltages charged in the buffer capacitor, wherein, in a normal touch mode, the buffer circuit integrates capacitance of the node capacitor to generate the voltage signal, and, in a proximity touch mode, the buffer circuit generates the voltage signal by following the voltages charged in the node capacitor.