Display Device Touch Detection via Time-Division Multiplexing
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Solution Overview
Problem
Existing touchscreen technologies face challenges in effectively implementing electromagnetic induction touch detection due to the direct employment of electrodes and wiring configurations designed for capacitance methods, leading to difficulties in satisfactory performance.
Innovation Solution
A display device configuration that includes a substrate, first electrodes, pixel electrodes, a display functional layer, common electrodes, and second electrodes, with a controller managing these components in a time-division manner to perform mutual-capacitive and electromagnetic induction touch detection by generating magnetic fields and electrostatic capacitance, improving detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electrodes and wiring configurations designed for capacitance methods are directly employed in electromagnetic induction method, then device complexity is reduced, but electromagnetic induction touch detection cannot be satisfactorily performed
Solution Approach 1:
The patent applies dynamics by making the electrode configurations adaptive and reconfigurable based on the detection method being used. The control circuit dynamically switches between capacitance mode and electromagnetic induction mode, adjusting the electrical connections and signal processing pathways accordingly. This allows the same physical electrodes to serve different functional purposes depending on the operational context, resolving the contradiction between device simplicity and detection reliability.
Solution Approach 2:
The patent employs parameter changes by modifying the electrical characteristics and operational parameters of the electrodes based on the detection method. In capacitance mode, electrodes operate with specific voltage levels and signal frequencies, while in electromagnetic induction mode, different parameters are applied to enable magnetic field generation and detection. This parameter adaptation allows satisfactory performance in both detection methods without requiring completely separate electrode systems.
2Measurement precision
If time-division manner is used to perform both mutual-capacitive and electromagnetic induction touch detection, then detection sensitivity of both methods is improved, but processing time and complexity increase
Solution Approach 1:
The patent implements periodic action by alternating between mutual-capacitive touch detection and electromagnetic induction touch detection in time-division multiplexed fashion. The control circuit periodically switches between these two detection methods, allocating specific time slots for each method to operate. This periodic switching enables both detection methods to achieve optimal sensitivity by dedicating full attention to each method during its active period, while the control processing complexity is managed through systematic timing and state management.
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
Enhances the detection sensitivity and effectiveness of both mutual-capacitive and electromagnetic induction touch detection methods, allowing for accurate detection of touch inputs on the display surface.
Implementation Method 1
either of the lines and the first electrodes are supplied with a first drive signal to generate a magnetic field
Implementation Method 2
the other of the lines and the first electrodes generate an electromotive force caused by the magnetic field
Implementation Method 3
the common electrodes are supplied with a second drive signal to generate electrostatic capacitance between the common electrodes and the second electrodes
Data Source
AI summary
A display device includes a substrate, first electrodes, pixel electrodes, a display functional layer, common electrodes, second electrodes stacked in this order. The display device further includes lines that are provided between the substrate and the display functional layer and intersect with the first electrodes in the plan view. In response to a control signal from a controller, the pixel electrodes are supplied with a pixel signal through the lines, and the common electrodes are supplied with a common signal in the display periods; either of the lines and the first electrodes are supplied with a first drive signal to generate a magnetic field, and the other thereof generate an electromotive force caused by the magnetic field in the first sensing period; the common electrodes are supplied with a second drive signal to generate electrostatic capacitance between the common electrodes and the second electrodes in the second sensing period.