Touch Detection Device Driving Back Phenomenon Noise Reduction
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Solution Overview
Problem
Conventional touch screen panels face challenges in detecting touch signals due to noise interference from common electrodes and parasitic capacitance, especially when integrated into liquid crystal display devices, leading to inaccurate recognition and increased manufacturing costs.
Innovation Solution
A touch detection device that utilizes a driving back phenomenon by applying a driving voltage to a driving capacitor connected to a touch pad, allowing for the detection of touch capacitance while minimizing noise interference from common electrodes and parasitic capacitance, enabling stable touch signal acquisition and facilitating the integration of touch screens into display devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional capacitive touch screen panel uses micro-current detection, then touch detection is achieved, but the device requires expensive detecting equipment and raises manufacturing costs
Solution Approach 1:
The patent changes the detection parameter from micro-current measurement to voltage measurement. By applying a driving voltage to a driving capacitor and detecting the voltage change (driving back phenomenon) caused by touch capacitance, the system achieves touch detection without requiring expensive micro-current sensing equipment, thereby reducing device complexity and manufacturing costs while maintaining detection accuracy
2Adaptability or versatility
If a touch screen panel is integrated into a liquid crystal display device, then functionality is enhanced, but noise from common electrodes and parasitic capacitance causes erroneous signal recognition
Solution Approach 1:
The patent extracts and eliminates the harmful factors (common electrode noise and parasitic capacitance) from the detection circuit. By using a driving capacitor connected to the touch pad and measuring the voltage change caused by touch capacitance, the system isolates the touch signal from interfering noise sources, enabling reliable touch detection even when integrated into liquid crystal display devices with common electrodes
Solution Approach 2:
The driving capacitor acts as an intermediary element between the touch pad and the detection circuit. It converts the touch capacitance change into a measurable voltage change through the driving back phenomenon, serving as a mediator that isolates the touch signal from noise generated by common electrodes and parasitic capacitance, thereby improving signal recognition accuracy
3Ease of manufacture
If a resistive type touch screen panel is used, then manufacturing is simple and cost is low, but transmittance is low and pressure is required for operation
Solution Approach 1:
The patent changes the operating principle from mechanical pressure-based detection to electrical capacitance-based detection. By measuring voltage changes caused by touch capacitance rather than requiring physical pressure to activate resistive layers, the system maintains manufacturing simplicity while dramatically improving ease of operation, allowing soft touches without pressure
4Adaptability or versatility
If a capacitive touch screen panel recognizes multiple touches and gestures, then functionality is improved, but detection errors occur and manufacturing complexity increases
Solution Approach 1:
The patent segments the touch detection into independent voltage measurement points across the touch pad surface. By dividing the detection into multiple discrete voltage measurement locations and using the driving back phenomenon at each point, the system achieves accurate multi-touch and gesture recognition while simplifying the manufacturing process through standardized voltage measurement circuits
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 effectively reduces erroneous signal recognition and simplifies the manufacturing process, enabling high-resolution touch detection and fine input capabilities, such as handwriting and drawing, while maintaining a single-layer active region and reducing manufacturing complexity.
Implementation Method 1
a driving capacitor (Cdrv) whose one side is connected to the touch pad and to the other side of which a driving voltage for detection of a touch input is applied
Implementation Method 2
a touch pad that forms the touch capacitance (Ct) between the touch input instrument and the touch pad
Implementation Method 3
a touch detector that is connected to the touch pad, and that detects a touch signal by using a driving back phenomenon when the touch capacitance (Ct) is added to the driving capacitor (Cdrv)
Data Source
AI summary
Provided is a touch detection device, touch detection method, and touch screen panel, which detects a touch signal by detecting a driving back phenomenon occurring in a touch pad by a driving voltage applied to a driving capacitor, and a display device with a built-in touch screen panel. The touch detection device that is added on top of a display device and detects occurrence of a touch capacitance (Ct) by an approach of a bodily finger (25) or a touch input instrument such as a conductor similar to the bodily finger, the touch detection device comprising: a touch pad (10) that forms the touch capacitance (Ct) between the touch input instrument and the touch pad; a driving capacitor (Cdrv) whose one side is connected to the touch pad (10) and to the other side of which a driving voltage for detection of a touch input is applied; a common voltage detector that detects a common voltage generated from the display device; a driving voltage generator that generates the driving voltage in synchronization with the common voltage; and a touch detector that is connected to the touch pad (10), and that detects a touch signal by using a driving back phenomenon when the touch capacitance (Ct) is added to the driving capacitor (Cdrv) according to occurrence or non-occurrence of a touch in the touch input instrument. A touch signal is detected while avoiding a point in time of a change of a common voltage state, and a driving voltage is applied through a driving capacitor connected to a touch detector, to thus detect whether or not a driving back phenomenon occurs in the touch detector and to thereby acquire a touch signal. Accordingly, an influence due to parasitic capacitance generated by noise, coupling phenomenon or other factors is minimized, to thus acquire a touch signal stably.