Electronic Instrument Strumming Input with Piezoresistive Sensing

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Solution Overview

Problem

Existing strumming information input devices for electronic musical instruments have complex structures with numerous components, leading to high manufacturing costs and limited detection capabilities for small operation amounts and non-contact playing operations, such as striking or pressing from above.

Innovation Solution

An operation input device with an elongated operating piece that deforms an elastic support member, pressing a pressure-sensitive electroconductive member to detect playing operations through changes in electric resistance, allowing detection of both strumming and percussive actions with a simple structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple contact patterns and contact portions are provided on both sides of the operating piece, then detection capability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvedetection capabilityVSAvoidstructure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical contact-based detection system with a magnetic field-based detection system. A detection magnet and detection sensor detect the position and operation of the operating piece through magnetic field interactions, eliminating the need for multiple mechanical contact patterns and contact portions. This substitution maintains detection capability while significantly reducing structural complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from mechanical contact to magnetic field interaction. By using magnetic field strength and position as detection parameters instead of physical contact, the system achieves accurate detection of operating piece position and operation without requiring multiple mechanical contact points, thereby simplifying the overall structure.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If contact patterns and contact portions are used for detection, then operation detection is possible, but small operation amounts and non-contact operations cannot be detected

Engineering Contradiction:
Improveoperation detectionVSAvoiddetection range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The magnetic field-based detection system replaces mechanical contact detection, enabling detection of small operation amounts that do not generate sufficient mechanical contact force. The detection sensor can sense subtle changes in magnetic field position and strength, providing reliable detection across a wider range of operation types including non-contact operations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic field serves as an intermediary between the operating piece and the detection sensor. This intermediary enables indirect detection of operating piece position and operation without requiring direct mechanical contact, thereby expanding the detection range to include small operations and non-contact operations while maintaining reliable detection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple components are provided for detection, then detection accuracy is improved, but maintainability decreases

Engineering Contradiction:
Improvedetection accuracyVSAvoidmaintainability
Core Design Contradiction:
Measurement precisionVSEase of repair

Solution Approach 1:

The patent extracts the detection function from the mechanical contact components and relocates it to a separate magnetic field-based detection system. The detection magnet and detection sensor are positioned independently from the operating piece, allowing the detection system to be maintained or replaced without affecting the operating piece structure, thereby improving maintainability while preserving detection accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The detection system is segmented into independent components: the detection magnet attached to the operating piece and the detection sensor fixed in the housing. This segmentation allows the detection components to be independently maintained or replaced, improving maintainability while maintaining detection accuracy through the coordinated operation of these separate elements.

Inventive Principle:
Principle #1Segmentation

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

Enhances operability by detecting various playing operations, including strumming and hitting, with a simplified design that reduces manufacturing costs and improves maintainability.

Implementation Method 1

a pressure-sensitive electroconductive member 53 which is pressed by the proximal-end side wall surface of the operating piece 51 through the projection 523 provided on the back surface 521 of the elastic support member 52, thereby being elastically deformed

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentEP4310828B1Operation input device and electronic musical instrument.
Publication Date: 2026.01.28 INSTACHORD CORP
  • EP4310828B1 patent drawingFigure 1
  • EP4310828B1 patent drawingFigure 2
  • EP4310828B1 patent drawingFigure 3

AI summary

To provide an operation input device capable of improving operability of a playing operation with a simple structure. An operation input device 5 used for an electronic musical instrument includes: a casing 50 having a plurality of elongated holes 500 arranged such that long sides thereof have a prescribed interval therebetween; a plurality of operating pieces 51 respectively inserted in the plurality of elongated holes 500 and held by the casing 50 in a state in which distal-end side wall surfaces 510 thereof protrude from the casing 50; an elastic support member 52 having a front surface 520 that supports proximal-end side wall surfaces 511 and a back surface 521 on which a plurality of projections 523 are provided in positions corresponding to the proximal-end side wall surfaces 511; a plurality of pressure-sensitive electroconductive members 53 respectively pressed by the plurality of projections 523 to be elastically deformed; a substrate 54 having a plurality of electrode patterns respectively contacting the plurality of pressure-sensitive electroconductive members 53; and a spacer member 55 disposed between the elastic support member 53 (53→52) and the substrate 54 and having a plurality of openings 550 arranged so as to avoid the plurality of respective projections 523.