Upper-Layer CDA Signal Line Layout for Faster Touch Detection
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Solution Overview
Problem
Conventional capacitive touch input devices face issues such as decreased touch sensitivity, detection errors due to increased capacitance and Dead Zones, and inaccuracies in object detection and coordinate determination due to wider CDA signal lines.
Innovation Solution
A novel layout method for CDA signal lines, where the widths are identical within a CDA column, and driving voltage is applied to adjacent signal lines to detect object capacitance, using a semiconductor IC to process the detected voltages based on specific equations, with multiplexers and storage devices to store and digitize the signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the CDA signal line width is increased, then the signal transmission stability is improved, but the touch detection sensitivity deteriorates due to enhanced capacitance of the common electrode
Solution Approach 1:
The patent applies different line widths to different signal lines based on their specific positions and functions. The CDA signal line width is optimized to be narrower than conventional widths to reduce capacitance and improve touch detection sensitivity, while other signal lines may have different widths suited to their requirements. This local optimization resolves the contradiction by tailoring the line width to the specific needs of touch detection rather than using a uniform width throughout.
2Power
If the CDA signal line width is increased, then the signal strength is improved, but detection errors increase due to increased time constant
Solution Approach 1:
The patent changes the critical parameter of signal line width to a smaller value than conventional designs. This parameter change reduces the time constant formed by the line capacitance and resistance, thereby improving the detection response speed and reducing detection errors. The signal strength is maintained through optimized signal transmission paths and other design considerations rather than increasing line width.
3Manufacturing precision
If the CDA signal line width is increased, then the manufacturing robustness is improved, but the Dead Zone width increases causing detection errors
Solution Approach 1:
The patent applies a narrower line width specifically to the CDA signal lines that are critical for touch detection, while other non-critical signal lines may have wider widths for manufacturing robustness. This localized application of different line width qualities allows the CDA signal lines to have minimal Dead Zone width for accurate object detection, while the overall device maintains manufacturing robustness through other appropriately designed signal lines.
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
Enhances touch detection sensitivity, minimizes detection errors, and reduces the width of Dead Zones, improving accuracy in object detection and coordinate calculation.
Implementation Method 1
This device detects the change in capacitance generated when an object such as a finger or pen approaches or touches the Capacitor Detection Area (hereinafter CDA) installed on the upper side of the display device
Data Source
AI summary
The present invention relates to the CDA that constitutes the capacitive detection device of the present invention placed on the upper side of the conductor. It aims to narrow the width of the far-distance CDA signal line, which was previously widened to reduce resistance, to be the same as the width of the near-distance signal line. As a result, this reduces the time constant in the far-distance CDA, enhancing the detection speed, and minimizes the width of the Dead Zone caused by the signal line, thereby reducing object detection errors or touch coordinate calculation errors.