Capacitive Touch Display Electrode Layout for Accurate Multi-Touch
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Solution Overview
Problem
Existing touch display devices struggle to detect multiple touches accurately using a single monolithic touch electrode, limiting touch performance and requiring separate touch panels that increase manufacturing costs.
Innovation Solution
A touch display device with a display panel incorporating a touch electrode and switch circuits, where a touch driving circuit applies signals to the electrode and calculates multi-touch points based on sensed values from multiple measurement positions, including corners and median points, enhancing touch detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single monolithic touch electrode is used for capacitance sensing, then the device structure is simple, but it can detect only a single touch and cannot detect multiple touches
Solution Approach 1:
The single monolithic touch electrode is segmented into multiple measurement positions (first measurement position, second measurement position, third measurement position, fourth measurement position) corresponding to different regions of the electrode. Each measurement position is equipped with its own switch circuit and touch driving circuit, enabling independent capacitance sensing at each position. This segmentation allows the system to detect multiple simultaneous touch points across the electrode surface while maintaining the overall electrode structure.
2Reliability
If multiple touch detection is implemented, then touch performance is improved, but manufacturing costs increase due to separate touch panels
Solution Approach 1:
The invention merges the touch sensing functionality directly into the display panel by integrating multiple measurement positions and their associated switch circuits onto the same substrate. This combination eliminates the need for separate touch panels, allowing the display panel to perform both display and multi-touch detection functions. The integration reduces manufacturing steps and costs while improving touch performance through multiple simultaneous touch points.
3Measurement precision
If multiple measurement positions are added to the touch electrode, then multi-touch detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The system employs dynamic control of switch circuits connected to each measurement position. The switch circuits are controlled to selectively connect different measurement positions to the touch driving circuit based on sensing requirements. This dynamic switching allows the system to manage multiple measurement positions efficiently, reducing the burden on the touch driving circuit at any given moment while maintaining the capability to detect multiple touch points simultaneously.
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 solution allows for accurate detection of multiple touches while maintaining image luminance and sharpness, reducing production costs, and optimizing the touch panel process.
Implementation Method 1
the touch sensor detects a touch based on a sensing result of change in capacitance of a surface of a touch electrode
Data Source
AI summary
Disclosed is a touch display device that detects multiple touches in a touch sensing scheme of sensing change in capacitance of a surface of a touch electrode. The touch display device includes a display panel including a touch electrode; a switch circuit connected to each of measurement positions of the touch electrode; and a touch driving circuit connected to each of the measurement positions of the touch electrode via the switch circuit, wherein the touch driving circuit is configured to apply a touch driving signal to the touch electrode, receive sensed values from the measurement positions based on an operation of the switch circuit, and calculate coordinates of multi-touch points on the touch electrode, based on the sensed values.