Coil-Shaped Touch Sensor Electrodes for Low-Noise Pen and Finger Input
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Solution Overview
Problem
Touch display devices experience coupling noise between touch sensors and surrounding electrodes, which deteriorates touch sensing performance, particularly when using both finger and pen inputs.
Innovation Solution
A touch display device with a coil-type structure featuring interlocked horizontal and vertical electrode lines in a coil shape, allowing for both capacitance-based finger touch sensing and inductance-based pen touch sensing, thereby reducing coupling noise and improving sensing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If various electrodes or lines are disposed around the touch sensor for additional functions, then the functionality and versatility of the touch display device is improved, but coupling noise between the touch sensor and surrounding electrodes increases, deteriorating touch sensing performance
Solution Approach 1:
The patent extracts the harmful coupling noise by introducing a ground electrode between the touch sensor electrode and surrounding electrodes. This ground electrode acts as a noise sink, separating and removing the harmful electromagnetic coupling path while preserving the useful sensing function of the touch sensor.
Solution Approach 2:
The ground electrode serves as an intermediary element positioned between the touch sensor electrode and surrounding electrodes. It mediates the electromagnetic interaction by providing a reference potential that reduces parasitic capacitance and minimizes coupling noise, allowing both the touch sensor and surrounding electrodes to coexist with reduced interference.
2Adaptability or versatility
If a coil-type structure is used for electrode lines, then inductance-based pen touch sensing capability is improved, but the structural complexity increases
Solution Approach 1:
The coil-type electrode structure provides multi-functionality by enabling both capacitance-based finger touch sensing and inductance-based pen touch sensing using the same electrode configuration. This universal design allows a single structural modification (coil shape) to support multiple sensing modes, reducing the need for separate specialized sensors.
Solution Approach 2:
The patent utilizes parameter changes in the electrode geometry by transforming straight electrode lines into coil-shaped electrodes. This geometric parameter change fundamentally alters the sensing mechanism from purely capacitive to inductive, enabling pen touch detection while maintaining the same basic electrode layout and control circuitry.
3Reliability
If separate sensors are used for finger touch and pen touch detection, then sensing performance for both modes is optimized, but device weight and complexity increase
Solution Approach 1:
The patent merges the finger touch sensing and pen touch sensing functions into a single integrated touch sensor system. By combining capacitive and inductive sensing capabilities in one sensor structure, it eliminates the need for separate sensors, thereby reducing device weight and complexity while maintaining reliable sensing performance for both touch modes.
Solution Approach 2:
The touch sensor is designed with universal multi-functionality to handle both finger and pen inputs through a single sensor array. The coil-type electrode structure enables the same sensor to perform both capacitive (finger) and inductive (pen) sensing, avoiding duplication of hardware components and reducing overall device weight.
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 coil-type structure effectively reduces noise interference, enabling reliable detection of both finger and pen touches while minimizing the need for separate sensors, thus enhancing touch sensing performance and device weight efficiency.
Implementation Method 1
a coil-type structure capable of sensing pen touch based on inductance
Implementation Method 2
enabling both capacitance-based finger touch sensing and inductance-based pen touch sensing
Data Source
AI summary
A touch display device may include a plurality of vertical electrode lines each extending in a column direction, a plurality of horizontal electrode lines each extending in a row direction, and a plurality of unit sensor areas where the plurality of vertical electrode lines and the plurality of horizontal electrode lines intersect. The plurality of unit sensor areas may include a first unit sensor area where a first vertical electrode line among the plurality of vertical electrode lines and a first horizontal electrode line among the plurality of horizontal electrode lines intersect, and, in the first unit sensor area, each of the first horizontal electrode line and the first vertical electrode line may have a coil shape.