Dual Mode Capacitive Touch Panel With Deformable Shield

Solution Overview

Problem

Conventional projected capacitive touch sensors cannot detect touch from non-conductive objects and struggle to distinguish multiple simultaneous points of contact, requiring additional patterned electrode layers that increase manufacturing costs and reduce sensitivity and mechanical robustness.

Innovation Solution

A dual-mode capacitive touch panel with a shield layer above an array of sensor electrodes, where the shield layer is spaced from the sensor electrodes and can be compressed by externally applied forces, allowing for the transmission or blocking of electric fields based on operation frequency, minimizing additional costs and maintaining lower layer integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional patterned electrode layers are added to detect force and multiple touches, then measurement capability is improved, but manufacturing cost increases and sensitivity decreases

Engineering Contradiction:

Improvetouch detection capabilityVSAvoidnumber of electrode layers

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The shield layer serves multiple functions: it acts as an electrode for detecting non-conductive objects, functions as a shield to block external electromagnetic interference, and enables force sensing through its deformable structure. This multi-functionality eliminates the need for separate patterned electrode layers for force detection, reducing manufacturing complexity while maintaining measurement precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the operational parameters by using the shield layer's physical deformation (change in spacing) as the sensing mechanism for force detection, rather than relying on additional patterned electrodes. The controller detects force by measuring changes in capacitance or impedance caused by the shield layer's displacement, achieving force sensing without increasing structural complexity.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If additional patterned electrode layers are added to detect force and multiple touches, then measurement capability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvetouch detection capabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The shield layer serves multiple functions: it acts as an electrode for detecting non-conductive objects, functions as a shield to block external electromagnetic interference, and enables force sensing through its deformable structure. This multi-functionality eliminates the need for separate patterned electrode layers for force detection, reducing manufacturing complexity while maintaining measurement precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the shield function with the sensing function by making the shield layer itself deformable and responsive to touch forces. This consolidation of functions into a single layer reduces the number of manufacturing steps and material layers required, directly lowering production costs while maintaining or improving measurement capabilities.

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If additional patterned electrode layers are added, then force detection capability is improved, but mechanical robustness decreases

Engineering Contradiction:

Improveforce detection capabilityVSAvoidmechanical robustness

Core Design Contradiction:

Measurement precisionVSStrength

Solution Approach 1:

The shield layer is designed as a flexible, deformable structure that can respond to touch forces. This flexible design allows the shield to act as both a protective element and a sensing element, maintaining mechanical robustness while enabling force detection through controlled deformation rather than requiring additional fragile patterned layers.

Inventive Principle:

Principle #30Flexible shells and thin films

4Measurement precision

If the shield layer is spaced closer to improve sensitivity, then detection sensitivity is improved, but mechanical robustness decreases

Engineering Contradiction:

Improvedetection sensitivityVSAvoidmechanical robustness

Core Design Contradiction:

Measurement precisionVSStrength

Solution Approach 1:

The shield layer is designed as a flexible, deformable structure that can respond to touch forces. This flexible design allows the shield to act as both a protective element and a sensing element, maintaining mechanical robustness while enabling force detection through controlled deformation rather than requiring additional fragile patterned layers.

Inventive Principle:

Principle #30Flexible shells and thin films

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

Enables detection of non-conductive objects and multiple simultaneous touch points with improved spatial resolution, sensitivity, and mechanical robustness without the need for additional patterned layers, reducing manufacturing costs and enhancing performance.

Implementation Method 1

the shield layer having a predetermined resistance that permits transmission of an electric field at a first frequency and prevents transmission of an electric field at a second frequency

Methodology Applied

Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

a spacing between the shield layer and the electrode layer is deformable as a result of a force applied to the shield layer due to a user touch

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 3

the controller configured to drive the shield layer and at least some sensor electrodes of the sensor electrode array at the first frequency in a first mode to measure the location of an object relative to the sensor substrate

Methodology Applied

Scientific EffectElectromagnetic field: Electric Field

Data Source

PatentUS8698769B2Dual mode capacitive touch panel

Publication Date: 2014.04.15 SHARP KK

AI summary

A dual mode capacitive touch panel includes a sensor substrate, an electrode layer comprising an array of sensor electrodes arranged over the sensor substrate, the array of sensor electrodes including a plurality of drive electrodes and a plurality of sense electrodes, each sensor electrode corresponding to a location on the sensor substrate, and a shield layer arranged over and spaced apart from the electrode layer. The shield layer includes a predetermined resistance that permits transmission of an electric field at a first frequency and prevents transmission of an electric field at a second frequency, wherein a spacing between the shield layer and the electrode layer is deformable as a result of a force applied to the shield layer due to a user touch, wherein the deformation alters a capacitance between the shield layer and a sensor electrode of the array. A controller is operatively coupled to the array of sensor electrodes, the controller configured to drive the shield layer and at least some sensor electrodes of the sensor electrode array at the first frequency in a first mode to measure a location of an object relative to the sensor substrate, and drive the shield and the at least some sensor electrodes at a second frequency in a second mode different from the first mode to measure a force applied toward the sensor substrate.