Capacitive Visual Key Structure for Adjustable Press Sensitivity

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Solution Overview

Problem

Conventional touch type key structures lack adjustable travel distance and response sensitivity, and do not provide intermediate states for key triggering, limiting their application and user customization.

Innovation Solution

A capacitive-type visual key structure is introduced, featuring a transparent keycap, an elastic element, and electrodes that change capacitance when pressed, allowing for adjustable sensitivity and intermediate states by detecting changes in spatial distance between electrodes, enabling more nuanced key press information and expanded application possibilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional touch type key structure with membrane switch is used, then the key structure can be triggered by pressing, but the travel distance and response sensitivity are fixed and cannot be adjusted

Engineering Contradiction:

Improveadjustability of travel distance and response sensitivityVSAvoidcomplexity of key structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the conventional mechanical membrane switch system with a capacitive sensing system. Instead of using a physical bump touching a membrane switch, the invention uses capacitive electrodes to detect key press states through changes in capacitance values, enabling adjustable sensitivity and multiple intermediate states without the limitations of fixed mechanical travel distance

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from mechanical contact to capacitive measurement. By monitoring capacitance changes between electrodes, the system can detect different press depths and states, allowing adjustable response sensitivity and multiple trigger thresholds that were impossible with fixed mechanical structures

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a conventional touch type key structure is used, then the key structure provides binary trigger states, but no intermediate states are available to expand applications

Engineering Contradiction:

Improveavailability of intermediate statesVSAvoidloss of press depth information

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

The patent implements a feedback mechanism where the capacitive sensing system continuously monitors capacitance changes and provides multiple intermediate state information. The system can distinguish between different press depths and states, giving feedback about the exact press level rather than just a binary triggered/not-triggered state, thereby preserving press depth information and enabling intermediate states

Inventive Principle:

Principle #23Feedback

3Illumination intensity

If a membrane switch with hollow portion is used, then the image can pass through for visual display, but the structure becomes more complex

Engineering Contradiction:

Improvelight transmissibility for visual displayVSAvoidcomplexity of key structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent uses transparent keycaps made of light-transmissible materials that allow images from the display panel to pass through clearly. The capacitive electrodes are integrated into thin film structures within the keycap, maintaining transparency while enabling sensing functionality without requiring complex hollow portions or separate lighting structures

Inventive Principle:

Principle #30Flexible shells and thin films

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 capacitive-type visual key structure enhances sensitivity and flexibility, allowing for customizable response and additional operational modes, such as a ready-to-press state, thereby expanding the device's functionality and user experience.

Implementation Method 1

a capacitive structure is formed by the first electrode and the second electrode collaboratively. When the transparent keycap is pressed down, the elastic element is correspondingly moved, and a spatial distance between the first electrode and the second electrode is changed. Consequently, at least one capacitance change value is formed.

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS12191853B2Control device with capacitive-type visual key structure

Publication Date: 2025.01.07 PRIMAX ELECTRONICS LTD

AI summary

A control device with a capacitive-type visual key structure is provided. The control device includes a covering member and a transparent keycap. The covering member includes an accommodation space. The transparent keycap is accommodated within the accommodation space. An elastic element, a first electrode, a key circuit board assembly with a second electrode and a display panel are accommodated within the accommodation space. When the transparent keycap is pressed down, the elastic element is correspondingly moved, and a spatial distance between the first electrode and the second electrode is changed. Consequently, a capacitance change value is formed. According to the capacitance change value, the control device judges whether the transparent keycap is pressed down and triggered.