Key Switch Mechanism With Mid-Travel Contact and Tactile Feedback

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Solution Overview

Problem

Conventional dome switches in user input devices are unresponsive for gaming applications due to slow activation times and lack of feedback, as they require full collapse for electrical contact and do not provide audible or tactile feedback.

Innovation Solution

A key switch mechanism using a conductive spring coupled to a dome with copper electrical contacts that establishes contact halfway through travel, providing fast response and tactile feedback, along with an actuator spring for audible feedback, reducing accidental activations and stress accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If dome switches are used for user input devices, then manufacturing cost is reduced, but response time becomes slow and gaming performance deteriorates

Engineering Contradiction:
Improvemanufacturing costVSAvoidresponse time
Core Design Contradiction:
Ease of manufactureVSSpeed

Solution Approach 1:

The switch mechanism is divided into separate functional components: a dome element for tactile feedback, a separate contact mechanism for electrical connection, and an actuator spring for reset. This segmentation allows each component to be optimized independently - the contact mechanism can establish connection before full dome collapse, improving response time while maintaining the simple dome structure for cost-effective manufacturing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The switch establishes electrical contact during the partial collapse of the dome, before complete compression is reached. This partial action approach allows the switch to activate earlier in the pressing sequence, reducing response time while still utilizing the simple dome structure for manufacturing efficiency.

Inventive Principle:
Principle #16Partial or excessive action

2Device complexity

If dome switches require full collapse for electrical contact, then structural simplicity is maintained, but activation time increases and responsiveness decreases

Engineering Contradiction:
Improvestructural simplicityVSAvoidactivation time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The contact mechanism is positioned and configured to establish electrical connection during the intermediate stage of dome compression, before full collapse occurs. This preliminary action of making contact earlier in the sequence reduces activation time while maintaining the simple overall dome switch structure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

An intermediary contact mechanism is introduced between the dome element and the electrical circuit. This intermediary can make contact during partial dome compression, serving as a mediator that enables earlier electrical connection without requiring the simple dome structure to be fundamentally changed.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If carbon is used as electrical conductor in dome switches, then manufacturing cost is reduced, but electrical connectivity becomes insufficient for fast response

Engineering Contradiction:
Improvematerial costVSAvoidelectrical connectivity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The electrical contact system uses composite construction with copper or copper alloy contacts combined with the dome structure. This composite approach provides superior electrical connectivity and reliability for fast response times while maintaining cost-effectiveness through the use of established materials and manufacturing processes.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The electrical conductivity parameter is improved by changing from carbon to copper or copper alloy materials in the contact mechanism. This material parameter change significantly enhances electrical connectivity and response reliability while remaining compatible with cost-effective manufacturing approaches.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If dome switches are used, then device simplicity is maintained, but audible and tactile feedback is insufficient for user satisfaction

Engineering Contradiction:
Improvemechanism simplicityVSAvoiduser feedback quality
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The feedback function is separated from the basic switching function. An independent actuator spring component provides tactile feedback and audible click through mechanical action, while the dome element maintains its simple structure for cost-effective manufacturing. This segmentation allows feedback quality to be improved without fundamentally complicating the overall mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The actuator spring is designed to produce mechanical vibration and audible click upon switch activation. This mechanical vibration provides satisfying tactile and audible feedback to users while using a simple spring mechanism that integrates well with the existing dome switch structure, maintaining overall simplicity.

Inventive Principle:
Principle #18Mechanical vibration

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 key switch mechanism offers faster response times and satisfying tactile feedback while reducing accidental activations, maintaining responsiveness and durability by using copper contacts and actuator springs for audible and tactile feedback.

Implementation Method 1

When the plunger is in the activation position, the elastomeric dome is elastically deformed by the plunger

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the moveable end portion is moved to contact the electrical contact

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

an actuator spring for audible feedback

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Data Source

PatentEP3747037B1Key switch mechanisms, user input devices and methods of fabricating a key switch mechanism
Publication Date: 2023.11.22 RAZER ASIA PACIFIC
  • EP3747037B1 patent drawingFigure 1~2
  • EP3747037B1 patent drawingFigure 3~4
  • EP3747037B1 patent drawingFigure 5

AI summary

According to various embodiments, there is provided a key switch mechanism including: a key button; a plunger attached to the key button and displaceable between a neutral position and an activation position; an elastomeric dome which, when the plunger is in the neutral position, is non-deformed and which, when the plunger is in the activation position, is elastically deformed by the plunger; a conductive spring having a stationary end portion and a moveable end portion, the stationary end portion electrically coupled to a circuit, and the moveable end portion coupled to the elastomeric dome in a manner to be moved when the plunger is displaced towards the activation position, in connection with the corresponding deformation of the elastomeric dome; and an electrical contact electrically coupled to the circuit, wherein, when the plunger is in the neutral position, the electrical contact is arranged at a distance from the moveable end portion, and, when the plunger is in the activation position, the moveable end portion is moved to contact the electrical contact.