Matrix Sensor Via Routing Reduces RC Load
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Solution Overview
Problem
Existing capacitive touch sensing devices face limitations in detecting the presence and motion of input objects, particularly when objects are spaced far from the surface, with mutual capacitance methods being ineffective for distant object detection and self-capacitance methods being better suited for single object detection.
Innovation Solution
The implementation of a capacitive touch sensing device with a matrix array of sensor electrodes and conductive routing traces, where each sensor electrode is coupled with multiple conductive routing traces via vias, reducing the RC load and enhancing detection capabilities by improving power consumption and settling time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mutual capacitance sensing methods are used to detect multiple input objects, then the ability to detect multiple objects and motion is improved, but effectiveness for detecting objects spaced far from the surface deteriorates
Solution Approach 1:
The sensing device is segmented into multiple sensor electrodes arranged in a matrix array, with each electrode independently coupled to the processing system via separate conductive routing traces. This segmentation allows each electrode to function as an independent sensing element, enabling both multi-object detection and extended sensing range through coordinated operation of multiple segments.
Solution Approach 2:
The patent transitions from planar routing to three-dimensional routing by utilizing vias to connect sensor electrodes to conductive routing traces on different layers. This dimensional change allows routing traces to extend beneath sensor electrodes without interfering with the sensing surface, reducing parasitic capacitance and enabling more effective detection of distant objects.
2Device complexity
If conventional conductive routing traces are used with sensor electrodes, then device structure is simplified, but RC load increases leading to higher power consumption and longer settling time
Solution Approach 1:
The patent employs multi-layer conductive routing traces connected via vias to reduce the physical length and parasitic capacitance of routing paths. By routing traces on separate layers rather than extending them across the sensing surface, the RC load is reduced while maintaining electrical connectivity, thereby lowering power consumption and settling time.
Solution Approach 2:
Vias serve as intermediary elements connecting sensor electrodes to conductive routing traces on different layers. These via connections enable efficient electrical coupling with reduced parasitic effects, acting as mediators that minimize the RC load between the sensing elements and the processing system without requiring complex planar routing.
3Device complexity
If conventional conductive routing traces are used with sensor electrodes, then device structure is simplified, but settling time increases
Solution Approach 1:
By utilizing multi-layer conductive routing traces connected through vias, the patent reduces the physical path length and parasitic capacitance of the routing network. This three-dimensional routing approach decreases the RC time constant, enabling faster settling time while maintaining structural simplicity through standardized layer connections.
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 configuration enables improved detection of input objects, including those far from the surface, with reduced power consumption and background capacitance, effectively addressing the limitations of existing technologies by enhancing the sensitivity and accuracy of touch sensing.
Implementation Method 1
The sensor routing traces are configured to reduce an RC load of the corresponding paired sensing elements compared to a base RC load of a plurality of base electrodes arranged in a base pattern
Implementation Method 2
Many proximity sensor devices utilize an array of sensor electrodes to measure a change in capacitance indicative of the presence of an input object, such as a finger or stylus, proximate the sensor electrodes
Implementation Method 3
In various embodiments, an input object near the sensor electrodes alters the electric field near the sensor electrodes, thus changing the measured capacitive coupling
Data Source
AI summary
Disclosed herein include an input device, processing system and methods for touch sensing. In one embodiment, an input device is provided that includes a plurality of sensing elements arranged in a sensor pattern and a plurality of conductive routing traces. Each conductive routing trace is conductively paired with a respective one of the plurality of sensing elements. The sensor routing traces are configured to reduce an RC load of the corresponding paired sensing elements compared to a base RC load of a plurality of base electrodes arranged in a base pattern that is identical to the sensor pattern. Each base sensor electrode is conductively paired with a base routing trace. The base sensor electrode and paired base routing trace have a size that is identical to a size of the paired sensing elements and conductive routing trace. The base routing trace terminates at the base sensor electrode to which the base routing trace is paired.