Capacitive Sensor Circuit for Proximity, Contact, and Press Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional capacitive sensors require complex detection processing due to the need to switch circuits to detect proximity, contact, and pressing, which complicates the detection process.

Innovation Solution

A capacitive sensor design featuring front-side electrodes, an elastic dielectric body, a shield electrode, and voltage output units that apply alternating-current voltages with specific amplitude relationships to easily detect proximity, contact, and pressing, without the need for circuit switching, using a detection unit with an operational amplifier circuit to process the capacitance changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If circuit switching is used to detect proximity, contact, and pressing, then detection functionality is achieved, but device complexity increases

Engineering Contradiction:

Improvedetection functionalityVSAvoidcircuit complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines proximity detection, contact detection, and pressing detection into a single capacitive sensor structure with one detection electrode and one shield electrode. By applying alternating current voltages to both electrodes simultaneously and measuring capacitance changes, the sensor can distinguish between proximity, contact, and pressing states without requiring separate circuits or switching mechanisms for each detection mode.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The capacitive sensor structure serves multiple detection functions (proximity, contact, pressing) through a single unified design. The detection electrode and shield electrode configuration, when driven by alternating current voltages, enables the same hardware to perform three different detection tasks by analyzing different capacitance change patterns, eliminating the need for separate specialized circuits.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If circuit switching is used to detect proximity, contact, and pressing, then detection functionality is achieved, but processing time increases

Engineering Contradiction:

Improvedetection functionalityVSAvoidprocessing time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent applies alternating current voltages continuously to both the detection electrode and shield electrode simultaneously, enabling continuous real-time detection of proximity, contact, and pressing states. This eliminates the need for sequential switching between different detection modes, allowing all three detection functions to operate concurrently without time delays associated with circuit switching.

Inventive Principle:

Principle #20Continuity of useful action

3Adaptability or versatility

If circuit switching is used to detect proximity, contact, and pressing, then detection functionality is achieved, but number of components increases

Engineering Contradiction:

Improvedetection functionalityVSAvoidnumber of components

Core Design Contradiction:

Adaptability or versatilityVSQuantity of substance

Solution Approach 1:

The patent merges the functionality of multiple detection circuits into a single capacitive sensor structure with one detection electrode and one shield electrode. By using alternating current voltage sources and measuring capacitance changes between these two electrodes, the system can detect proximity, contact, and pressing states without requiring separate physical circuits, switches, or components for each detection mode.

Inventive Principle:

Principle #5Merging (Combining)

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 straightforward detection of proximity, contact, and pressing with reduced processing time and simplified circuitry, minimizing the number of wires and components required, resulting in a more efficient and compact sensor design.

Implementation Method 1

an elastic dielectric body disposed below the one or plurality of front-side electrodes

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

capacitive sensor has: one or a plurality of front-side electrodes including one or more detection electrodes

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS20240011801A1Capacitive sensor

Publication Date: 2024.01.11 ALPS ALPINE CO LTD

AI summary

A capacitive sensor has: one or more front-side electrodes including at least one detection electrode; an elastic dielectric body disposed below the front-side electrodes; a shield electrode disposed below the elastic dielectric body; a first, second, and third voltage output unit that respectively outputs a first, second, and third AC voltage; and a detection unit that detects a proximity, a contact, and pressing of a detection target to the detection electrode. The first, second, and third AC voltages have substantially the same frequency. The amplitude of the first AC voltage is larger than or equal to the amplitude of the second AC voltage. The amplitude of the third AC voltage is smaller than the amplitude of the second AC voltage. The first AC voltage is output to a driving unit coupled to the detection electrode with capacitances intervening between them. The second AC voltage is applied to the detection electrode.