Flexible Detachable Keypad for Capacitive Touchscreens

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Solution Overview

Problem

Current external keyboards for portable devices like tablets and smartphones are rigid and bulky, making them inconvenient for storage and do not provide the tactile feedback users prefer for long-term typing.

Innovation Solution

A detachable keypad with a flexible insulation pad, conductive keycaps, and conductive contact parts that can be placed on a capacitive touch surface to simulate key presses, providing tactile feedback and aligning with virtual keyboard interfaces for accurate input.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a rigid external keyboard with electronic components is used, then tactile feedback for key presses is provided, but the volume and complexity of the device increase

Engineering Contradiction:

Improvetactile feedbackVSAvoidkeyboard volume

Core Design Contradiction:

Ease of operationVSVolume of stationary object

Solution Approach 1:

The patent uses a flexible insulating pad as the base structure instead of a rigid keyboard body. This flexible pad can be bent and folded, dramatically reducing the keyboard's volume when not in use while maintaining the ability to provide tactile feedback through its elastic deformation when keys are pressed.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent removes unnecessary electronic components from the keyboard structure, keeping only the essential conductive elements for touch screen interaction. This extraction of non-essential components reduces device complexity and volume while preserving the core typing function.

Inventive Principle:

Principle #2Taking out (Extraction)

2Volume of stationary object

If a virtual keyboard interface is used, then the device remains compact, but tactile feedback is lost and typing accuracy decreases

Engineering Contradiction:

Improvedevice volumeVSAvoidtyping accuracy

Core Design Contradiction:

Volume of stationary objectVSEase of operation

Solution Approach 1:

The flexible insulating pad with conductive elements acts as an intermediary between the user's fingers and the touch screen. It provides physical tactile feedback through elastic deformation while maintaining electrical contact with the capacitive touch screen, bridging the gap between physical keyboard feel and virtual keyboard functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional mechanical switch system with a capacitive touch system. Instead of mechanical contacts, conductive elements on the flexible pad interact with the capacitive touch screen to register key presses, eliminating mechanical complexity while providing tactile feedback through the pad's elastic properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If conductive elements are added to provide tactile feedback, then typing accuracy improves, but the risk of short circuit on capacitive touch screen increases

Engineering Contradiction:

Improvetouch input accuracyVSAvoidshort circuit risk

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The insulating pad provides electrical insulation at the base level, while conductive elements are strategically placed only at specific key positions where contact is needed. This localized conductivity minimizes short circuit risk while maintaining typing accuracy at essential input points.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The keyboard uses a composite structure combining insulating material (flexible pad) with conductive elements (contact portions). This composite design provides both electrical insulation to prevent short circuits and localized conductivity for accurate touch input registration on the capacitive screen.

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 flexible keypad allows for efficient storage and provides the tactile feedback users need, enhancing the typing experience by allowing key presses to register accurately with the virtual keyboard interface, while reducing the complexity of electronic components and storage issues.

Implementation Method 1

The panel has a capacitive touch surface. The portable electronic apparatus provides a virtual keyboard interface on the capacitive touch surface

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS8941614B2Portable electronic apparatus and key pad thereof

Publication Date: 2015.01.27 WISTRON CORP

AI summary

A portable electronic apparatus and a key pad thereof are disclosed. The portable electronic apparatus includes a processing module, a panel, and a key pad. The processing module provides a virtual keyboard interface on a capacitive touch surface of the panel. The key pad is placed on the capacitive touch surface in a detachable way and corresponds to the virtual keyboard interface. The key pad includes a plurality of conductive keycaps and a plurality of conductive contact part correspondingly connected to the conductive keycaps. A user can press the conductive keycaps by fingers to make the corresponding conductive contact part touch the virtual keyboard interface, so as to achieve a touch input. Therefore, the invention can provide the user the feeling of pressing keys by use of the key pad when the user is using the virtual keyboard interface, which satisfies the use habit of the user.