Laminated Key Stopper Structure for Full Stroke and Aftertouch Accuracy

Solution Overview

Problem

Conventional keyboard devices struggle to accurately detect aftertouch due to issues with stoppers being either too rigid, which prevents significant displacement of the hammer, or too soft, leading to unintentional detection of aftertouch during normal performance.

Innovation Solution

A keyboard device with a key-pressing stopper comprising a first cushion layer and a rigid layer laminated on the surface, which regulates key swinging and a sensor to detect aftertouch by accurately distinguishing between normal performance and aftertouch.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the stopper is formed to be rigid, then the full stroke feel is improved, but the aftertouch detection precision deteriorates

Engineering Contradiction:

Improveaftertouch detection precisionVSAvoidfull stroke feel

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The stopper is divided into two functional segments: a first stopper portion made of soft elastic material for full stroke feel, and a second stopper portion made of hard material for precise aftertouch detection. This segmentation allows each portion to fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the stopper are assigned different material properties: the first portion (contacting the key) uses soft elastic material to provide full stroke feel, while the second portion (contacting the pressure sensor) uses hard material to ensure precise aftertouch detection. This local differentiation of material quality resolves the contradiction between comfort and precision.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If the stopper is formed to be soft, then the aftertouch detection precision is improved, but the full stroke feel deteriorates

Engineering Contradiction:

Improvefull stroke feelVSAvoidaftertouch detection precision

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The stopper is divided into two functional segments: a first stopper portion made of soft elastic material for full stroke feel, and a second stopper portion made of hard material for precise aftertouch detection. This segmentation allows each portion to fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the stopper are assigned different material properties: the first portion (contacting the key) uses soft elastic material to provide full stroke feel, while the second portion (contacting the pressure sensor) uses hard material to ensure precise aftertouch detection. This local differentiation of material quality resolves the contradiction between comfort and precision.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If a single material stopper is used, then the device complexity is reduced, but the performance versatility deteriorates

Engineering Contradiction:

Improveperformance versatilityVSAvoidstopper structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The stopper is divided into two functional segments: a first stopper portion made of soft elastic material for full stroke feel, and a second stopper portion made of hard material for precise aftertouch detection. This segmentation allows each portion to fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The stopper uses a composite structure combining soft elastic material and hard material in specific portions. This composite approach enables the stopper to provide both full stroke feel and precise aftertouch detection, enhancing performance versatility while maintaining a unified component design.

Inventive Principle:

Principle #40Composite materials

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

The solution allows for precise detection of aftertouch while maintaining a full stroke feel during normal performance, improving durability and reducing noise, and ensuring accurate differentiation between normal and aftertouch performance.

Implementation Method 1

a first cushion layer; and a rigid layer. The rigid layer is laminated on a surface layer side with respect to the first cushion layer and is more rigid than the first cushion layer

Methodology Applied

Scientific EffectCushioning: Damping

Implementation Method 2

a first cushion layer; and a rigid layer. The rigid layer is laminated on a surface layer side with respect to the first cushion layer and is more rigid than the first cushion layer

Methodology Applied

Scientific EffectRigidity:

Data Source

PatentUS20250210020A1Keyboard device and method for regulating key swinging

Publication Date: 2025.06.26 ROLAND CORP

AI summary

A rigid layer 121 more rigid than a first cushion layer 120 that is relatively soft is laminated on a surface layer side of the first cushion layer 120, so the performer can be imparted with a relatively rigid full stroke feel due to the rigid layer. Thus, the white key 2a can be suppressed from being pushed into the aftertouch performance region. Meanwhile, at the time when the rigid layer 121 is strongly pushed during aftertouch performance, the white key 2a can be significantly displaced due to the deformation of the relatively soft first cushion layer 120. Therefore, aftertouch can be detected with high accuracy.