Resonant Inductive Touch Sensing With Dynamic Frequency Adjustment
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Solution Overview
Problem
Existing pen touch sensing devices face challenges such as increased thickness due to multiple loop antennas, complex circuitry, limited frequency changeability, inaccurate coordinate detection, and environmental sensitivity, leading to power consumption and reliability issues.
Innovation Solution
A touch sensing system with XY electrodes and a single surrounding antenna, using a resonant inductive signal with varying periods to sense pen location and pressure, integrated into a display panel without adding thickness, and employing digital signal processing to analyze resonance signals for precise detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple loop antennas are used to detect pen location in XY coordinate system, then measurement precision is improved, but device complexity and thickness increase
Solution Approach 1:
The patent divides the touch sensing area into multiple measurement regions, each served by a single loop antenna. The controller sequentially activates different loop antennas corresponding to different XY coordinate regions, enabling precise location detection without requiring all antennas to be active simultaneously, thus reducing circuit complexity
Solution Approach 2:
The patent transitions from spatial arrangement of multiple antennas to temporal multiplexing. Instead of having multiple antennas operate simultaneously in space, the system uses a single antenna that switches operation over time to serve different measurement regions, converting a spatial problem into a temporal solution that reduces device complexity
2Measurement precision
If separate antenna layer is added to display panel to implement loop antennas, then measurement precision is improved, but length of stationary object increases
Solution Approach 1:
The patent makes the existing touch screen electrodes serve dual functions: both display and touch sensing. The same electrode structure that displays images is also used as the antenna for pen detection, eliminating the need for a separate antenna layer and maintaining thin display panel structure while preserving sensing capability
3Ease of operation
If pulse generator is used to transmit resonant inductive signal, then ease of operation is improved, but adaptability worsens due to limited frequency changeability
Solution Approach 1:
The patent implements dynamic frequency adjustment of the resonant inductive signal based on the detected pen pressure. The controller varies the signal frequency according to the measurement results, allowing the system to adapt to different touch conditions and optimize detection accuracy for varying pressure levels while maintaining simple operation
4Ease of operation
If analog comparator is used to compare received signals, then ease of operation is improved, but measurement precision worsens due to inability to accurately represent coordinates
Solution Approach 1:
The patent replaces the traditional analog comparator approach with a digital signal processing system. The controller performs digital calculations and comparisons to determine touch location and pressure, providing more precise coordinate representation while maintaining operational simplicity through automated processing
5Ease of operation
If analog circuit is used to process resonance signal, then ease of operation is improved, but reliability worsens due to environmental sensitivity
Solution Approach 1:
The patent substitutes analog signal processing with digital signal processing in the controller. The controller performs digital calculations and analysis of the resonance signals, providing more stable and reliable measurements that are less susceptible to environmental variations such as temperature and humidity, while maintaining ease of operation through automated digital processing
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
The system effectively senses both fingers and pens without increasing display panel thickness, allows easy frequency changes, improves accuracy, reduces power consumption, and enhances reliability by minimizing environmental dependencies.
Implementation Method 1
a resonant inductive signal of an electromagnetic field for inducing a resonance of a pen is propagated through an electromagnetic resonance path through an antenna and is transmitted to the pen
Implementation Method 2
a resonant inductive signal of an electromagnetic field for inducing a resonance of a pen is propagated through an electromagnetic resonance path through an antenna and is transmitted to the pen
Implementation Method 3
a resonance signal of an electromagnetic field generated from a resonant circuit of the pen is propagated through the electromagnetic resonance path and is received by the antenna
Implementation Method 4
a resonance signal of an electromagnetic field generated from a resonant circuit of the pen is propagated through the electromagnetic resonance path and is received by the antenna
Data Source
AI summary
A touch sensing system and a method for driving the same. The touch sensing system includes a pen with a resonant circuit embedded therein, XY electrodes including X electrodes and Y electrodes substantially perpendicular to the X electrodes, an antenna surrounding the XY electrodes, and a first touch driving circuit. The first touch driving circuit supplies a resonant inductive signal to the XY electrodes, analyzes a resonance signal received through the antenna, and decides a location and a pen pressure of the pen. The resonant inductive signal includes N periods each having a different duration, and wherein N is a positive integer equal to or greater than 2.