Touch Sensor Dummy Routing Line for Noise Reduction
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Solution Overview
Problem
Conventional touch sensing apparatuses face increased noise in the outermost readout channel due to parasitic capacitance, which reduces sensing capability, and attempts to mitigate this by increasing the interval between the ground routing line and the outermost readout channel result in a wider bezel area.
Innovation Solution
Incorporating a dummy routing line between the ground routing line and the outermost readout channel, with a signal of the same phase as the readout signal, to minimize parasitic capacitance deviation and noise, while maintaining a narrow bezel width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the interval between the ground routing line and the outermost readout channel is increased, then the parasitic capacitance deviation is reduced, but the width of the bezel area is increased
Solution Approach 1:
A dummy routing line is introduced as an intermediary element between the ground routing line and the outermost readout channel. This dummy routing line acts as a mediator that reduces parasitic capacitance deviation without requiring increased spacing, thereby maintaining compact bezel dimensions while improving signal quality
Solution Approach 2:
The dummy routing line is designed to replicate the characteristics of the outermost readout channel, creating a virtual copy that experiences similar parasitic effects. By copying the channel's electrical characteristics, the dummy line enables accurate noise compensation and calibration without physically relocating components
2Length of stationary object
If the ground routing line is located close to the outermost readout channel, then the bezel width is reduced, but the parasitic capacitance deviation is increased
Solution Approach 1:
The dummy routing line serves as a protective intermediary that allows close positioning of the ground line while preventing harmful parasitic effects. It mediates between the conflicting requirements of compact layout and noise reduction by providing a buffer zone that can be electrically calibrated
Solution Approach 2:
The dummy routing line is pre-configured with matching electrical characteristics before operation, allowing the system to preemptively compensate for parasitic effects. This preliminary setup enables the system to maintain low noise levels even when components are positioned closely together
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 noise in the outermost readout channel by minimizing parasitic capacitance deviation, thereby enhancing sensing capability without increasing the bezel width.
Implementation Method 1
parasitic capacitance formed between a ground routing line and an outermost readout channel is increased, thereby increasing parasitic capacitance deviation between outer readout channels positioned on an outer portion
Data Source
AI summary
A touch sensing apparatus includes a touch sensor and a touch controller for sensing whether touch is present from a readout signal of the touch sensor as well as driving the touch sensor, wherein the touch sensor includes a plurality of scan channels including a plurality of first sensing electrodes arranged in a first direction in a sensing area, a plurality of readout channels including a plurality of second sensing electrodes arranged in a second direction that crosses the first direction in the sensing area, a ground routing line formed to surround the sensing area in a bezel area surrounding the sensing area, a dummy routing line formed between the ground routing line and an outermost readout channel among the plural readout channels in the bezel region, wherein a signal with the same phase as the outermost readout channel is supplied to the dummy routing line.