Touch Panel Sensing Resolution via Reference Capacitor Mediator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional capacitance type touch panels face limitations in miniaturizing sensing electrodes due to the loading effect, leading to insufficient touch signal strength and inability to distinguish touch actions, especially when using a touch pen.
Innovation Solution
The touch panel design incorporates a substrate with scan lines, data output lines, and touch sensing units, including a sensing electrode with a breach, a reference capacitor, conducting lines, an output circuit, and a reset circuit, allowing the output circuit to determine signal levels based on the electric potential of a reference point, thereby reducing the sensing electrode area and enhancing sensing resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing electrode area is reduced to improve sensing resolution, then the sensing resolution is improved, but the touch signal strength becomes insufficient
Solution Approach 1:
The patent introduces a reference capacitor as an intermediary element to mediate between the sensing electrode and the readout circuit. The reference capacitor stores reference charge that compensates for signal decay, enabling the use of smaller sensing electrodes while maintaining sufficient touch signal strength. This intermediary component allows the system to achieve both high sensing resolution and adequate signal strength.
Solution Approach 2:
The patent changes the electrical parameters of the sensing system by introducing a reference capacitor with specific capacitance value and configuring it in a specific circuit arrangement. This parameter change enables the system to compensate for reduced capacitance variation in smaller sensing electrodes, thereby maintaining touch signal strength while improving sensing resolution.
2Measurement precision
If the sensing electrode area is reduced to improve sensing resolution, then the sensing resolution is improved, but the ability to distinguish touch actions becomes insufficient
Solution Approach 1:
The reference capacitor serves as a mediator that enhances the reliability of touch action detection. By providing a stable reference charge level, it enables the readout circuit to reliably distinguish between different touch actions (such as finger touch versus touch pen touch) even when the sensing electrode area is reduced and capacitance variation is minimal.
Solution Approach 2:
The patent implements a feedback mechanism where the reference capacitor's stored charge is used to compensate for signal variations. This feedback approach ensures that the system can reliably detect and distinguish different touch actions by comparing the actual signal against the reference level, thereby maintaining detection reliability with smaller sensing electrodes.
3Measurement precision
If the sensing electrode area is reduced, then the sensing resolution is improved, but the loading effect causes signal decay
Solution Approach 1:
The reference capacitor acts as an intermediary that compensates for signal energy loss due to loading effect. By storing and providing reference charge, it offsets the signal decay that occurs when small sensing electrodes are used, enabling the system to maintain adequate signal levels while achieving high sensing resolution.
Solution Approach 2:
The reference capacitor is pre-charged to a reference level before the actual touch sensing operation. This preliminary action of charging the reference capacitor allows it to compensate for signal decay during the sensing process, ensuring that even small sensing electrodes can produce detectable signals despite the loading effect.
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 design enables improved sensing resolution and allows the use of touch pens as touch components by amplifying output signals, even with reduced sensing electrode size, effectively addressing the limitations of conventional touch panels.
Implementation Method 1
When the touch panel 100 is touched by a finger of a user, a capacitance between the finger and the sensing electrodes 120s is increased. Therefore, a touch position can be obtained according to variation of electrostatic capacitance of the sensing electrodes 120s.
Data Source
AI summary
A touch panel includes a substrate, scan lines, data output lines, a signal processing unit and touch sensing units. Each touch sensing unit includes a sensing electrode, a reference capacitor, an output circuit and a reset circuit. The sensing electrode is disposed in a breach of the sensing electrode. The reference capacitor, the output circuit and the reset circuit are disposed on the substrate and in the breach. The output circuit, the reset circuit, the reference capacitor and the sensing electrode are electrically coupled to a reference point. The output circuit is configured to output touch signals to the corresponding data output line. The signal processing unit is configured to obtain electric potential of the data output line and perform a corresponding processing step. When the touch sensing unit is out of working, the reference point is reset to a predetermined electric potential.