Touchscreen Sensor Layout for Force Sensitivity and Position Accuracy

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing touchscreen designs with a piezoelectric body positioned under a capacitive sensor face limitations in detection sensitivity due to restricted curvature of the piezoelectric body and limited space for mounting electronic components.

Innovation Solution

A touchscreen configuration where a piezoelectric sensor is placed on the front side of a capacitive sensor, allowing for increased pressing force detection sensitivity and position detection accuracy, with the piezoelectric sensor's electrodes positioned across the piezoelectric layer to enhance sensitivity without overlapping the capacitive sensing area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the piezoelectric body is positioned under the capacitive sensor, then the structure is simplified, but the detection sensitivity is limited due to restricted curvature

Engineering Contradiction:

Improvestructural complexityVSAvoidpressing force detection sensitivity

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent inverts the conventional layer arrangement by placing the piezoelectric sensor on the front side of the capacitive sensor instead of underneath it. This inversion allows the piezoelectric body to achieve greater curvature when pressed, thereby improving detection sensitivity while maintaining structural integration

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of manufacture

If the piezoelectric body is positioned under the capacitive sensor, then manufacturing is easier, but the space for mounting electronic components is limited

Engineering Contradiction:

Improveassembly easeVSAvoidspace for electronic components

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

By inverting the layer arrangement and placing the piezoelectric sensor on the front side, the back side of the capacitive sensor becomes available for mounting electronic components, thereby increasing the available space for electronics while maintaining manufacturing feasibility

Inventive Principle:

Principle #13The other way round (Inversion)

3Device complexity

If the piezoelectric sensor electrodes overlap the capacitive sensing area, then both functions are integrated, but position detection accuracy deteriorates

Engineering Contradiction:

Improvesensor integrationVSAvoidposition detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the sensor area by creating distinct zones: the piezoelectric sensor electrodes are positioned in regions that do not overlap with the capacitive sensing area, allowing each sensor type to operate in its dedicated zone while maintaining overall system integration

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the touchscreen are assigned different functions: the capacitive sensing area is optimized for position detection while the piezoelectric sensor regions are positioned elsewhere for force detection, allowing each area to perform its specialized function with high precision

Inventive Principle:

Principle #3Local quality

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 increases the sensitivity of pressing force detection and position detection, while also allowing for easier integration of electronic components on the back side of the capacitive sensor, improving overall performance and design flexibility.

Implementation Method 1

a piezoelectric sensor positioned on the front side of the capacitive sensor in a front-to-back direction from the front to the back of the input device, and configured to change its output in response to a force applied to the piezoelectric sensor from its front side

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The capacitive sensor includes a capacitive sensing area where the capacitive sensor is configured to perform a sensing operation

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10298231B2Input device

Publication Date: 2019.05.21 ALPS ALPINE CO LTD

AI summary

An input device includes a capacitive sensor and a piezoelectric sensor. The piezoelectric sensor is positioned on the front side of the capacitive sensor in a front-to-back direction from the front to the back of the input device, and is configured to change its output in response to a force applied to the piezoelectric sensor from its front side. The piezoelectric sensor includes a piezoelectric layer and a first electrode and a second electrode positioned across the piezoelectric layer from each other in the front-to-back direction. The capacitive sensor includes a capacitive sensing area where the capacitive sensor is configured to perform a sensing operation. The first electrode and the second electrode of the piezoelectric sensor do not overlap the capacitive sensing area when viewed in the front-to-back direction.