Capacitive Touch Keycap Layout for Extra Keyboard Inputs

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Solution Overview

Problem

Existing keyboards face challenges in adding more available keys without requiring users to exit the 'typing with both hands' posture, especially in compact layouts, and struggle with cost control and interaction efficiency.

Innovation Solution

A touch keycap with a circuit board and capacitive sensing touch elements integrated into the keycap body or keyboard, allowing for additional touch inputs without altering the traditional keypress mechanism, and enabling intuitive operations like volume adjustment and screen zoom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a conventional keyboard with physical keys is used, then the input method is simple and direct, but it occupies large space and is not suitable for portable devices

Engineering Contradiction:
Improvekeyboard space occupationVSAvoidinput method simplicity
Core Design Contradiction:
Area of stationary objectVSEase of operation

Solution Approach 1:

The patent replaces the mechanical key structure with a touch-sensitive surface that detects finger contact through capacitive or resistive sensing. This eliminates the need for physical key caps, switches, and mechanical linkages, thereby dramatically reducing the keyboard's area while maintaining input functionality through touch gestures and on-screen overlays.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention employs a flexible touch-sensitive film or shell that can be integrated into portable device displays. This thin-film structure provides the necessary tactile feedback and input detection without the bulk of mechanical keys, enabling compact keyboard layouts that adapt to the device's form factor.

Inventive Principle:
Principle #30Flexible shells and thin films

2Measurement precision

If the surface of the key cap is made rough to increase friction, then fingerprint recognition is improved, but cleaning becomes difficult and dirt accumulates

Engineering Contradiction:
Improvefingerprint recognition accuracyVSAvoidcleaning ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies different surface properties to different regions of the touch interface. The fingerprint sensing area maintains a smooth, non-porous surface that resists dirt accumulation and allows easy cleaning, while specific localized zones incorporate micro-structures or material variations that enhance fingerprint pattern detection without compromising overall cleanability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses composite material structures combining hydrophobic coatings, oleophobic layers, and micro-textured surfaces that simultaneously improve fingerprint recognition by enhancing sweat and oil pattern visibility while maintaining smooth surfaces that prevent dirt adhesion and facilitate easy wiping.

Inventive Principle:
Principle #40Composite materials

3Shape

If transparent materials are used for key caps to improve aesthetics, then appearance is enhanced, but durability and scratch resistance decrease

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidscratch resistance
Core Design Contradiction:
ShapeVSStrength

Solution Approach 1:

The patent employs durable touch-sensitive films with scratch-resistant coatings that can be applied over the display surface. These films maintain the aesthetic transparency or desired appearance while providing a protective layer that resists scratching, wear, and environmental damage, thereby solving the durability issue without sacrificing visual appeal.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention uses composite material structures combining transparent substrates with hard coating layers such as silicon oxide, silicon nitride, or diamond-like carbon coatings. These composite structures provide both the desired aesthetic transparency and enhanced scratch resistance, combining the benefits of visual clarity with mechanical durability.

Inventive Principle:
Principle #40Composite materials

4Adaptability or versatility

If multiple functional layers are added to the key cap for various functions, then functionality is enhanced, but the structure becomes complex and production cost increases

Engineering Contradiction:
Improvefunctional versatilityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into a unified touch-sensitive interface structure. The same touch-sensitive film and control circuitry that enable keyboard input also support display functionality, gesture recognition, and biometric sensing. This merging of functions into a single integrated system avoids the need for separate mechanical components for each function, thereby reducing structural complexity while maintaining versatility.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention designs the touch interface to serve multiple purposes: it functions as a keyboard input device, a display overlay, a gesture-sensing surface, and a fingerprint scanner. This multi-functional design allows a single structural platform to replace what would traditionally require multiple separate components, reducing overall system complexity and production costs while enhancing adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 touch keycap enhances keyboard functionality by allowing two or more key combinations to be triggered with one finger, maintaining the 'typing with both hands' posture, and improving interaction efficiency and cost-effectiveness.

Implementation Method 1

a transparent bead (220) having a spherical shape and disposed on the key cap (201)

Methodology Applied
Scientific EffectSpherical geometry:

Implementation Method 2

transparent bead (220)...configured to increase a surface area of the key cap (201) and to transmit light

Methodology Applied
Scientific EffectLight refraction: Refraction

Data Source

PatentEP4557060A1Touch-control key cap, keyboard, and keyboard touch-control input assembly
Publication Date: 2025.05.21 XX HMI ELECTRONICS CO LTD
  • EP4557060A1 patent drawingFigure 1~2
  • EP4557060A1 patent drawingFigure 3~4
  • EP4557060A1 patent drawingFigure 5~6

AI summary

The present disclosure relates to a technical field of keyboards, and provides a touch keycap. The touch keycap includes a circuit board and a keycap body, where the circuit board is located on the keycap body and/or a keyboard; the circuit board is provided with a touch circuit; the touch circuit is electrically connected to a capacitive sensing touch element; the capacitive sensing touch element is one or more of a touch key, a touch slider, and a touch pad; the touch circuit is provided with a microcontroller unit (MCU); the capacitive sensing touch element is electrically connected to the MCU; the capacitive sensing touch element is located at any position of an inner surface, an interior, and an outer surface of a top wall of the keycap body; alternatively, the capacitive sensing touch element is located at any position of an inner surface, an interior, and an outer surface of a side wall of the keycap body; and alternatively, the capacitive sensing touch element is located at an edge of the keycap body. A keyboard using the touch keycap can increase the number of keys on the basis of a given number of key positions, thereby improving interaction efficiency. The present disclosure further provides a keyboard touch input assembly, which can be used in combination with a keyboard or be used alone.