Touch Detection Using Common Electrodes and Guard Signals
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Solution Overview
Problem
Conventional display devices with touch detection functions require the same number of detection circuits as sensor electrodes, limiting their ability to increase sensor electrodes, improve detection performance, or expand display panel size.
Innovation Solution
A display device and touch detection method that utilize a sensor drive controller to select common electrodes as sensor electrodes, input a guard signal to reduce capacitance between them, and employ a self-capacitive system for touch detection, allowing for fewer detection circuits than common electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of sensor electrodes is increased to improve detection performance, then detection accuracy is improved, but the number of detection circuits must be increased proportionally, increasing device complexity
Solution Approach 1:
The patent applies multi-functionality by enabling common electrodes (originally used solely for display purposes) to serve dual purposes: maintaining display function while simultaneously acting as sensor electrodes for touch detection. This eliminates the need for separate dedicated sensor electrodes and their corresponding detection circuits, thereby improving detection capability without proportionally increasing device complexity
Solution Approach 2:
The patent merges the display electrode system and touch sensing system into a unified structure where common electrodes perform both display and sensing functions. By combining these previously separate functions into a single electrode system, the patent reduces the overall number of components and detection circuits required
2Area of stationary object
If the size of display panel is increased, then display area is expanded, but the number of sensor electrodes and detection circuits must be increased, increasing device complexity
Solution Approach 1:
The patent enables the common electrode system to serve dual purposes across the entire display area, allowing expanded display panels to maintain touch detection capability without requiring additional dedicated sensor electrodes or detection circuits proportional to the increased area
3Measurement precision
If guard signal is input to common electrodes to reduce capacitance, then detection accuracy is improved, but additional control complexity is introduced
Solution Approach 1:
The patent implements self-service by having the common electrodes receive guard signals that automatically compensate for parasitic capacitance effects. The system uses the existing common electrode infrastructure to generate its own correction signals, reducing the need for external correction mechanisms and minimizing additional control complexity
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 enables flexible handling of increased sensor electrodes and larger display sizes while maintaining high detection accuracy, reducing the number of detection circuits needed and minimizing unnecessary capacitance generation.
Implementation Method 1
employ a self-capacitive system for touch detection
Data Source
AI summary
According to one embodiment, a display device includes a plurality of gate lines, a plurality of data lines intersecting with the gate lines, a plurality of pixel electrodes provided in areas defined by the gate lines and the data lines, and a sensor drive controller which includes a plurality of common electrodes facing the pixel electrodes and detects a touch by using the common electrodes. The sensor drive controller selects at least one of the common electrodes as a sensor electrode, detects a touch by using the sensor electrode, and inputs, to the other common electrodes, a guard signal for reducing generation of capacitance between the other common electrodes and the sensor electrode.