Sensor Device Gap Layer Stress Relaxation

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Solution Overview

Problem

Thin substrates in flexible devices often deflect, causing stress that deteriorates sensor characteristics, particularly in sensor layers detecting contact or pressure.

Innovation Solution

A sensor device with a gap layer comprising a bonding region and a relaxation region is introduced between the substrate and the sensor layer, where the bonding region bonds the substrate to the sensor layer and the relaxation region relaxes stress applied from the substrate, thereby mitigating deflection-induced stress on the sensor layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a thin substrate is used for the flexible device, then flexibility and suppleness are improved, but substrate deflection occurs causing stress on the sensor layer

Engineering Contradiction:

ImproveflexibilityVSAvoidsensor characteristics

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The gap layer is divided into two functional regions: a bonding region that adheres the sensor layer to the substrate and a relaxation region that absorbs stress. This segmentation allows the structure to simultaneously maintain attachment and reduce stress transmission to the sensor layer, resolving the contradiction between flexibility and sensor reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The gap layer acts as an intermediary between the substrate and the sensor layer. It provides a buffer zone that decouples the mechanical stress from the substrate while maintaining the structural connection, thereby protecting the sensor layer from deflection-induced stress and improving sensor characteristics.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the sensor layer is bonded directly to the substrate, then structural stability is improved, but stress from substrate deflection deteriorates sensor characteristics

Engineering Contradiction:

Improvestructural stabilityVSAvoidsensor characteristics

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

Different regions of the gap layer are assigned different functional qualities: the bonding region provides strong adhesion for structural stability, while the relaxation region provides stress absorption for sensor protection. This local differentiation of properties allows simultaneous achievement of structural stability and sensor reliability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The gap layer functions as a composite structure combining bonding and relaxation functionalities. This composite approach allows the system to exhibit both strong adhesion characteristics and stress-relief characteristics, resolving the contradiction between structural stability and sensor protection.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10386971B2Sensor device, display unit, and input unit

Publication Date: 2019.08.20 SONY GROUP CORP

AI summary

A sensor device includes: a sensor layer provided at a position facing a surface, of a substrate having an operation surface, opposite to the operation surface, and configured to detect a contacted position or a pressed position on the operation surface; and a gap layer located in a gap between the substrate and the sensor layer. The gap layer includes a bonding region bonding the substrate to the sensor layer, and a relaxation region relaxing stress applied from the substrate to the sensor layer.