Protruding Key Structure with Crest Line for Tactile Recognition

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Solution Overview

Problem

Miniaturization of keys on electronic devices such as PDAs and mobile phones results in reduced recognition and increased accidental activation due to the size disparity between keys and fingers, leading to poor user interaction.

Innovation Solution

A key structure featuring protruding keys with a curved-convex surface and crest line design that reduces accidental activation by providing distinct tactile recognition and a groove between keys for precise finger placement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If keys are miniaturized to fit limited space on the front surface, then the device can be made smaller and more compact, but the recognition of the key deteriorates and the user easily touches other undesired keys

Engineering Contradiction:
Improvefront surface areaVSAvoidkey recognition
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The patent applies local quality by creating a crest line feature specifically at the top center of each key's curved-convex surface. This localized geometric feature provides enhanced tactile recognition without increasing the overall key size, allowing users to distinguish individual keys through touch despite the miniaturized layout.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes curvature by designing each key with a curved-convex surface instead of a flat surface. The crest line runs along the top of this curved surface, creating a tactile landmark that improves key identification. The curved geometry provides natural finger guidance and prevents accidental activation of adjacent keys.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Area of stationary object

If keys are miniaturized to fit limited space on the front surface, then the device can be made smaller and more compact, but the user easily touches other undesired keys

Engineering Contradiction:
Improvefront surface areaVSAvoidaccurate key activation
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The crest line feature is locally positioned at the top center of each key, creating a unique tactile identifier that guides finger placement. This localized feature ensures that users can accurately target the intended key without accidentally activating adjacent keys, thereby improving activation reliability in compact layouts.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The curved-convex surface with its crest line creates a natural tactile guide that directs the user's finger to the correct key. The curvature provides physical feedback that distinguishes the target key from surrounding keys, reducing the probability of accidental activation and improving overall input accuracy.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Shape

If a curved surface is used on the key, then the appearance is improved and the key provides a tactile sensation, but the manufacturing complexity increases

Engineering Contradiction:
Improvekey surface shapeVSAvoidkey manufacturing
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The patent employs a curved-convex surface with a crest line that can be efficiently manufactured using standard molding or injection molding techniques. The curvature is designed with simple geometric parameters that allow for cost-effective production while maintaining the tactile and aesthetic benefits of a curved surface.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP2075815B1Key structure
Publication Date: 2013.04.17 HTC CORP
  • EP2075815B1 patent drawingFigure 1A~2
  • EP2075815B1 patent drawingFigure 3
  • EP2075815B1 patent drawingFigure 4

AI summary

A key structure including at least two protruding keys and a key frame is provided. The at least two protruding keys are arrayed adjacently. Each of the at least two protruding keys has a first side edge, a second side edge and a protrusion. The second side edge is opposite to the first side edge. The protrusion has a curved-convex surface, a first side surface and a second side surface. The curved-convex surface is getting protruding inwardly from the first side edge and the second side edge. The top end of the curved-convex surface has a crest line. The first side surface passes through the end points of the first side edge, the second side edge and the crest line in the same side. The second side surface is opposite to the first side surface. The key frame is used for carrying the at least two protruding keys.