Key Switch Device Bottom-Out Mitigation

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Solution Overview

Problem

Existing key switch devices experience undesirable 'bottom-out' feelings when small keystrokes are made, as the lower end face of the key top or guide mechanism impacts the sheet laminated on the base plate, leading to an unpleasant tactile feedback.

Innovation Solution

A key switch device design featuring a base plate, a sheet laminated on the base plate, a key top above the sheet, and an elastic dome between the sheet and key top, with projections on the key top or guide mechanism that impact a receiving portion on the base plate, mitigating the impact and reducing the 'bottom-out' feeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a small keystroke is made, then the key top can be pressed down with less force, but the lower end face of the key top or guide mechanism impacts the sheet causing bottom-out feeling

Engineering Contradiction:

Improvekey press easeVSAvoidbottom-out feeling

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies beforehand cushioning by providing a gap between the upper sheet and lower sheet at the portion corresponding to the lower end face of the key top. This gap is prepared in advance to prevent direct impact between the key top/guide mechanism and the base plate, cushioning the impact before it reaches the harmful threshold and eliminating the bottom-out feeling.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If the key top is pressed down at a portion distant from the center, then the key can be operated with different finger positions, but the lower end face or guide mechanism impacts against the sheet causing undesirable tactile feedback

Engineering Contradiction:

Improvefinger position flexibilityVSAvoidimpact sensation

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by providing the gap between the upper sheet and lower sheet specifically at the portion corresponding to the lower end face of the key top, while maintaining the structural integrity of the sheet in other areas. This localized modification allows different finger positions to press the key top without causing impact, as the gap is positioned exactly where the lower end face may contact during off-center pressing.

Inventive Principle:

Principle #3Local quality

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 design effectively suppresses the 'bottom-out' feeling even for small keystrokes by buffering the impact with projections and receiving portions, enhancing user experience by reducing tactile feedback.

Implementation Method 1

an elastic dome that is disposed between the sheet and the key top and is configured to press the sheet in response to the key top being pressed down

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS10438759B2Key switch device

Publication Date: 2019.10.08 LENOVO (SINGAPORE) PTE LTD

AI summary

One aspect provides a key switch device including: a base plate; a sheet laminated on the base plate; a key top disposed above the sheet; and an elastic dome that is disposed between the sheet and the key top and is configured to press the sheet in response to the key top being pressed down. Other aspects are described and claimed.