Capacitive Sensor Device for Small Pressing Force Detection

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Solution Overview

Problem

Existing input devices struggle to detect small pressing forces effectively, limiting their application in new areas.

Innovation Solution

A sensor device with a capacitive element that includes a support layer with a second structure of shorter height, allowing for the detection of small pressing forces through the action of this structure, and utilizing a mutual or self-capacitance system with electrodes and a reference electrode to enhance sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional capacitive element is used, then the device can detect pressing forces, but it cannot detect small pressing forces effectively

Engineering Contradiction:
Improvepressing force detection sensitivityVSAvoidsupport layer structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The support layer is segmented into multiple structures with different heights (first structures and second structures). This segmentation allows the capacitive element to detect small pressing forces by measuring capacitance changes between electrodes, while the varied heights provide different mechanical support levels to enhance detection sensitivity without requiring a completely complex device architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the support layer are given different heights (local quality variation). The first structures have a first height and the second structures have a second height different from the first. This local quality difference creates zones with varying mechanical properties, allowing the device to optimize both sensitivity for small forces and structural stability in different areas.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If the support layer uses a single uniform structure, then the device is simple to manufacture, but it cannot achieve high sensitivity for small pressing forces

Engineering Contradiction:
Improvepressing force detection sensitivityVSAvoidsupport layer fabrication
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The support layer is divided into multiple structures with different heights that can be fabricated using standard semiconductor manufacturing techniques such as spin coating with multiple layers of photoresist or other patterning methods. This segmentation approach maintains ease of manufacture through established processes while achieving the sensitivity required for detecting small pressing forces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The height parameter of the support layer structures is varied to optimize sensitivity. By changing the height parameter (first height vs. second height) of different support structures, the device achieves enhanced sensitivity for detecting small pressing forces while still using conventional fabrication methods to vary these parameters across the device area.

Inventive Principle:
Principle #35Parameter changes

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 the detection of small pressing forces with high sensitivity, expanding the device's applicability to new applications.

Implementation Method 1

a sensor device including a capacitive element... based on a change in capacitance of the capacitive element

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

one of the first substrate and the second substrate includes an elastic layer lower in rigidity than the second substrate

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2824549B1Sensor device, input device, and electronic apparatus
Publication Date: 2019.08.07 SONY GROUP CORP
  • EP2824549B1 patent drawingFigure 1~2(C)
  • EP2824549B1 patent drawingFigure 3
  • EP2824549B1 patent drawingFigure 4~5

AI summary

[Object] To provide a sensor device, an input device, and an electronic apparatus that are capable of detecting a small pressing force. [Solving Means] A sensor device includes: a first surface and a second surface opposed to each other; a support layer including a first structure partially arranged between the first and second surfaces and having a first height, and a space portion formed between the first and second surfaces; and a capacitive element including a first electrode and a second electrode, the first electrode being arranged on one of the first and second surfaces, the second electrode being arranged to be opposed to the first electrode, the capacitive element being configured to generate a change in capacitance between the first and second electrodes in accordance with a change in distance between the first and second surfaces opposed to each other via the space portion.