Shared Wiring for Display and Touch Detection
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Solution Overview
Problem
Existing display devices with touch detection functions face challenges in minimizing the frame area while reducing the impact of touch detection on the display, as they require separate wirings for display drive voltage and touch drive signals, which occupy additional space and can affect display performance.
Innovation Solution
A display device with a touch detection function that includes a matrix of pixel electrodes, multi-divided drive electrodes, a display functional layer, a control device for image display control, a touch detection electrode forming capacitance with drive electrodes, and selection switches, where the control device supplies display drive voltage and touch drive signals to the same wiring at different times, allowing for reduced frame area and minimized display interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate wirings are provided for display drive voltage and touch drive signals, then the display device can perform both display and touch detection functions, but the frame area increases and the device becomes more complex
Solution Approach 1:
The patent combines the display drive electrode and touch detection electrode into a single shared electrode structure. The same electrode serves dual purposes: driving the liquid crystal display and detecting touch input through capacitance changes, thereby eliminating the need for separate wirings and reducing frame area.
Solution Approach 2:
The drive electrode is designed to perform multiple functions simultaneously. It acts as both the display drive electrode for liquid crystal control and the touch detection electrode for sensing external proximity objects, making the system more versatile without increasing structural complexity.
2Adaptability or versatility
If separate wirings are provided for display drive voltage and touch drive signals, then the display device can perform both display and touch detection functions, but the device complexity increases
Solution Approach 1:
The patent merges the display drive wiring and touch detection wiring into a single shared wiring structure. By using the same electrode and wiring for both display driving and touch detection, the patent significantly reduces the complexity of the wiring system while maintaining full functionality.
3Ease of operation
If touch detection operation is performed, then the touch detection function works, but it affects the display performance
Solution Approach 1:
The patent applies AC drive signals for touch detection at specific periods or time slots, rather than continuously. By periodically switching between display drive mode and touch detection mode, the system can perform touch detection without causing continuous interference to the display, and the liquid crystal molecules have time to stabilize between switches.
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 configuration enables a thinner profile, larger screen, or higher definition displays by reducing the frame area and minimizing the effect of touch detection on the display, while maintaining effective touch detection capabilities.
Implementation Method 1
a touch detection electrode facing the drive electrodes and forming a capacitance between the touch detection electrode and the drive electrodes
Implementation Method 2
capable of detecting an external proximity object, which is externally positioned in proximity, based on a change in an electrostatic capacitance
Data Source
AI summary
A display device with is touch detection function is provided and includes display area where electrodes are arranged in matrix having first and second directions crossing above substrate; common electrodes provided so as to face pixel electrodes; pixel signal lines each coupled to pixel electrodes, extending in first direction; control device for performing image display control and including drive signal generator and source driver; single first wire to which both display drive voltage and touch drive signal are supplied from drive signal generator, and selection switches for selecting common electrodes, wherein the drive signal generator includes first and second voltage generators for generating first and second voltages, and switching circuit for switching between first and second voltages, and wherein selection switches each coupled to single first wire via first coupling conductor and coupled to common electrode via second coupling conductor are arranged in frame area along single first wire, and are overlapped by single first wire that is supplied with display drive voltage from drive signal generator and that is supplied with touch drive signal from drive signal generator.