Keyboard Control Modules for Ghost-Free Multi-Key Input

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Solution Overview

Problem

Existing keyboard control systems face issues with key mapping conflicts, misjudgment of key presses due to simultaneous key presses, high costs, and inefficient response times caused by diode-based and resistor-based designs, leading to poor performance and increased manufacturing complexity.

Innovation Solution

A keyboard control system with multiple key control modules, each independently connected to a set of keys, generating and transmitting distinct key control signals to a main control module, eliminating the need for scanning the entire keyboard matrix and reducing processing delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a keyboard matrix is used with multiple keys pressed simultaneously, then key combination input is enabled, but key mapping conflicts (ghost keys) occur due to signal misjudgment

Engineering Contradiction:

Improvekey combination input capabilityVSAvoidkey press detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The keyboard control system is divided into multiple independent key control modules, where each module is responsible for detecting and processing signals from specific keys. This segmentation isolates the detection pathways, preventing signal interference between simultaneously pressed keys and eliminating ghost key problems while maintaining full key combination capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each key control module acts as an intermediary between the physical key press and the main control module. These intermediaries process and validate key press signals independently before transmitting them to the main controller, ensuring accurate key identification even when multiple keys are pressed simultaneously.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If diodes are embedded in membrane or soldered to PCBA to prevent key mapping conflicts, then ghost key problems are prevented, but manufacturing complexity and costs increase

Engineering Contradiction:

Improvekey mapping conflict preventionVSAvoidmanufacturing process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical/electrical diode-based conflict prevention system with a software-based key control module architecture. Instead of using physical diodes to block reverse current, the system uses independent control modules with firmware logic to detect and validate key presses, eliminating the need for complex PCB modifications and diode embedding while achieving the same ghost key prevention效果.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system changes the approach from hardware-level current direction control (using diodes) to software-level signal processing and validation. By modifying the control architecture from a passive electrical system to an active software-controlled system, the patent simplifies manufacturing while maintaining reliability.

Inventive Principle:

Principle #35Parameter changes

3Speed

If the entire keyboard matrix is scanned once every millisecond to enhance response time, then key response speed is improved, but charge-discharge time delay is wasted for about 48% of the scan period

Engineering Contradiction:

Improvekey response timeVSAvoidcharge-discharge time delay waste

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

Each key control module continuously monitors its assigned keys and is ready to detect key presses at any moment. This preliminary preparation eliminates the need to wait for the next matrix scan cycle, allowing immediate detection and reporting of key presses without wasting time on scanning other keys that are not being pressed.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system transitions from a static, periodic scanning approach to a dynamic, event-driven architecture. Key control modules continuously monitor their assigned keys and dynamically report only when changes occur, optimizing the balance between response speed and time efficiency by eliminating unnecessary scanning during stable periods.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10817075B2Keyboard control system and computer input system allowing a single pin to correspond to a single key when pressed on the keyboard key

Publication Date: 2020.10.27 CHICONY ELECTRONICS CO LTD

AI summary

A keyboard control system and a computer input system thereof are disclosed. The keyboard control system is used in a keyboard of the computer input system, wherein the keyboard has a plurality of keys. The keyboard control system includes a plurality of key control modules and a main control module. Each key control module is electrically connected to a plurality of keys so as to generate a key control signal according to the actuation of any one of the keys, wherein each key control module is electrically connected to different keys. The main control module is electrically connected to a plurality of key control modules for executing the key control signal.