Single Layer Capacitive Sensor Routing Trace Interference

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Solution Overview

Problem

Capacitive coupling between input objects and routing traces outside the user input region in capacitive sensor devices leads to unwanted interference, affecting the accuracy and reliability of input detection.

Innovation Solution

A single-layer capacitive sensor design with transmitter and receiver electrodes in a common stackup layer, where routing traces and transmission traces are strategically positioned to minimize crossings and utilize anisotropic conductive film bonding, and transmission traces are used to establish a baseline for unwanted coupling detection and compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If routing traces are extended into the user input region to couple with transmitter and receiver electrodes, then electrical connection is achieved, but unwanted capacitive coupling and interference increase

Engineering Contradiction:

Improveelectrical connectionVSAvoidcapacitive coupling interference

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent divides the sensor into distinct regions: a user input region containing transmitter and receiver electrodes, and a separate border region containing routing traces. This spatial segmentation prevents routing traces from entering the user input region, eliminating unwanted capacitive coupling while maintaining electrical connections through the border region's routing traces that couple to electrodes without crossing into the sensing area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The border region acts as an intermediary zone between the user input region and the external circuitry. Routing traces are positioned in this border region to couple with transmitter and receiver electrodes, serving as an intermediate connection path that avoids direct interference in the user input region while maintaining electrical connectivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If transmitter and receiver electrodes are positioned in a common stackup layer, then manufacturing complexity is reduced, but routing trace crossings and interference increase

Engineering Contradiction:

Improvestackup layer configurationVSAvoidrouting trace interference

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the functional areas by placing transmitter and receiver electrodes in the user input region separately from routing traces in the border region. This spatial separation ensures that even though both exist in the same common stackup layer, the routing traces do not cross through the user input region, preventing interference while maintaining manufacturing simplicity.

Inventive Principle:

Principle #1Segmentation

3Measurement precision

If transmission traces are added to establish baseline for coupling detection, then interference compensation is enabled, but device complexity increases

Engineering Contradiction:

Improveinput detection accuracyVSAvoidtrace configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

Transmission traces are introduced as intermediary elements positioned in the border region to establish baseline measurements for unwanted capacitive coupling. These traces serve as reference elements that enable interference compensation without requiring complex multi-layer configurations, maintaining measurement precision while adding minimal structural complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 reduces unwanted capacitive couplings, enhancing the accuracy and reliability of input detection by compensating for interference and improving the overall usability of capacitive sensing input devices.

Implementation Method 1

utilize anisotropic conductive film bonding

Methodology Applied

Scientific EffectAnisotropic conduction: Anisotropy

Implementation Method 2

Capacitive coupling between input objects and routing traces outside the user input region in capacitive sensor devices

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS9268435B2Single layer capacitive sensor and capacitive sensing input device

Publication Date: 2016.02.23 SYNAPTICS INC

AI summary

A single-layer capacitive sensor comprises a user input region and a border region proximate to and outside of the user input region. The user input region includes a plurality of transmitter electrodes that are disposed within the user input region. The user input region also comprises a plurality of receiver electrodes disposed in a common stackup layer with the plurality of transmitter electrodes within the user input region such that the transmitter electrodes and the receiver electrodes make no crossings of one another in the common stackup layer or in any other layer within the user input region. The border region comprises a plurality of routing traces extending from the border region into the user input region to couple with the transmitter electrodes and the receiver electrodes. The border region also comprises a plurality of transmission traces disposed entirely within the border region.