Photo Sensor Touch Panel Capacitance Balancing
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Solution Overview
Problem
Photo sensor type touch panels suffer from inferior detection accuracy due to variations in coupling capacitor capacitance between readout and data lines, leading to non-continuous touch signal tracking during user interactions, especially when high gray level images are displayed and column inversion driving is used.
Innovation Solution
The touch panel design includes readout lines electrically connected in parallel, with coupling capacitors between readout and adjacent data lines of different polarities having equal overall capacitance, ensuring that touch signals are not interfered with by data signal polarity inversion, thus maintaining accurate touch detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If readout lines are disposed between adjacent data lines with different polarities, then touch sensing function is achieved, but coupling capacitor capacitance variations cause signal interference and detection accuracy degradation
Solution Approach 1:
The patent applies parameter changes by making the coupling capacitor capacitance values equal between readout lines and adjacent data lines of different polarities. This is achieved by adjusting the spacing between readout lines and data lines, or by introducing compensation structures that equalize the capacitance values, thereby eliminating the harmful signal interference while maintaining the touch sensing function.
Solution Approach 2:
The patent introduces compensation capacitors as intermediary elements connected between the readout line and data lines. These compensation capacitors act as mediators to balance the total coupling capacitor capacitance on both sides of the readout line, thereby compensating for the inherent capacitance variations and preventing signal interference during column inversion driving.
2Ease of manufacture
If column inversion driving approach is used, then display panel fabrication is simplified, but coupling capacitor capacitance changes cause touch signal variations and broken line issues
Solution Approach 1:
The patent changes the capacitance parameter configuration by equalizing the coupling capacitor values between readout lines and adjacent data lines of different polarities. This parameter adjustment ensures that the total capacitance remains constant during column inversion driving, thereby maintaining touch signal continuity and preventing broken line issues while preserving the fabrication simplicity of column inversion driving.
Solution Approach 2:
The patent implements a feedback mechanism through compensation capacitors that dynamically balance the coupling capacitor capacitance during column inversion driving. The compensation capacitors provide feedback to maintain equal capacitance values on both sides of the readout line, ensuring stable touch signals throughout the driving cycle and eliminating the broken line problem.
3Device complexity
If readout lines have unequal coupling capacitors, then manufacturing is simpler, but touch signal recognition becomes inconsistent across different frame times
Solution Approach 1:
The patent changes the capacitance parameter configuration by equalizing the coupling capacitor values between readout lines and adjacent data lines of different polarities. This parameter adjustment ensures consistent signal recognition across different frame times while maintaining reasonable manufacturing complexity through systematic design of the readout line and data line spacing.
Solution Approach 2:
The patent introduces compensation capacitors as intermediary elements that balance the coupling capacitor capacitance on both sides of the readout line. These compensation capacitors act as mediators to equalize the total capacitance values, ensuring consistent touch signal recognition across different frame times while adding only minimal complexity to the overall device 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
This design enhances touch detection accuracy by stabilizing touch signals, preventing the broken line issue during user input, and ensuring consistent tracking of touch points.
Implementation Method 1
a coupling capacitor is respectively formed between the readout line and the two adjacent data line
Data Source
AI summary
A photo sensor type touch panel includes a plurality of readout lines electrically connected in parallel. The overall capacitance of a coupling capacitor between the readout lines connected in parallel and adjacent data lines having one type of polarity is equal to the overall capacitance of a coupling capacitor between the readout lines connected in parallel and adjacent data lines having the other type of polarity.