Touch Detection Pulse Compensator for Display Common Lines
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Solution Overview
Problem
In liquid crystal display devices with integrated touch detection, the coupling noise from data signals affects the common electrode, leading to poor touch detection accuracy due to excessive voltage application during both display and touch signal periods.
Innovation Solution
A display device configuration with a pulse compensator that generates a second pulse signal to reduce potential variations at common lines, allowing for independent voltage control during touch detection periods, thereby minimizing noise interference and enhancing touch detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the common electrode is disposed in a strip shape to add resolution to the touch function, then the touch detection resolution is improved, but the driving electrode is influenced by coupling noise from data signals leading to poor touch detection accuracy
Solution Approach 1:
The common electrode is divided into multiple independent strip-shaped regions, each controlled by separate common lines. This segmentation allows selective voltage application to specific regions during touch detection, reducing the impact of coupling noise from data signals on the overall touch detection accuracy while maintaining high resolution.
Solution Approach 2:
The patent implements periodic switching between display mode and touch detection mode. During touch detection periods, the common electrode voltage is adjusted or suspended to minimize coupling noise interference. This periodic action allows the system to achieve high touch detection resolution by temporarily optimizing the electrical environment for detection while maintaining display functionality during other periods.
2Reliability
If Vcom feedback control is always applied to the common electrode, then the display function is maintained, but excessive voltage is applied to the driving electrode during touch signal periods leading to poor touch detection
Solution Approach 1:
The Vcom feedback control is made dynamic by selectively applying it only during display periods and suspending or adjusting it during touch detection periods. The system dynamically switches between display optimization and touch detection optimization, allowing high touch detection accuracy by temporarily modifying the voltage application strategy during detection windows while maintaining reliable display function during other periods.
Solution Approach 2:
The patent implements periodic switching between display mode and touch detection mode. During touch detection periods, the common electrode voltage is adjusted or suspended to minimize coupling noise interference. This periodic action allows the system to achieve high touch detection resolution by temporarily optimizing the electrical environment for detection while maintaining display functionality during other periods.
3Adaptability or versatility
If the driving electrode and detection electrode are formed outside the liquid crystal display panel, then the touch detection function is added, but the thickness of the display device increases
Solution Approach 1:
The patent merges the common electrode of the liquid crystal display with the driving electrode of the touch panel into a single integrated structure. The detection electrode is formed on the opposite side of the liquid crystal layer from the common electrode, eliminating the need for separate driving and detection electrodes outside the panel. This merging reduces the overall device thickness while maintaining full touch detection functionality through the integrated electrode structure.
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 enables a low-profile display device with improved touch detection accuracy by reducing noise interference and optimizing voltage application, ensuring effective touch detection without compromising display functionality.
Implementation Method 1
a pulse compensator, the pulse compensator generating a second pulse signal based on the first pulse signal and the potential input from each of the common lines, the second pulse signal reducing a variation in potential at each of the common lines in response to a potential at each of the source lines
Implementation Method 2
a common line driving circuit including a pulse generator that sequentially drives the plurality of common lines, the pulse generator generating a first pulse signal for each of the plurality of common lines
Implementation Method 3
an electrostatic capacitance type touch panel includes a driving electrode and a detection electrode
Data Source
AI summary
A display device with built-in touch detection function, the display device includes source lines, detection lines, common lines, gate lines, pixels, control elements, each applying to a corresponding pixel a voltage, a common line driving circuit including a pulse generator that sequentially drives the common lines, the pulse generator generating a first pulse signal for each of the common lines, a pulse compensator, the pulse compensator generating a second pulse signal based on the first pulse signal and the potential input from each of the common lines, the second pulse signal reducing a variation in potential at each of the common lines in response to a potential at each of the source lines, the pulse compensator outputting the second pulse signal to a corresponding common line, and a touch detector that detects a position specified by a user according to the second pulse signal.