Hybrid Keyboard Switch Array With Partial Subarray Scanning

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Solution Overview

Problem

Contemporary input devices, such as keyboards, face issues with contact-based switches that wear out over time, leading to unreliable performance and low signal-to-noise ratios due to mechanical or chemical degradation, while contactless switches consume more power and have higher latency.

Innovation Solution

A hybrid switch system combining contact-based and contactless switches, where the contact-based switch generates a first signal to wake the device and trigger scanning of the contactless switch, optimizing power usage and reliability by grouping switches into subarrays to reduce the number of send/receive lines and scan only active columns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contactless switches are used, then reliability is improved, but power consumption increases

Engineering Contradiction:

Improveswitch reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically switches between two operational modes: a low-power mode using contact-based switches for basic detection, and a high-reliability mode using contactless switches for active scanning. This dynamic adaptation allows the system to optimize between power consumption and reliability based on operational needs.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The contactless switches are scanned periodically rather than continuously, with scanning triggered by wake signals from contact-based switches. This periodic operation reduces overall power consumption while maintaining reliability when needed.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If contactless switches are scanned continuously, then key press detection accuracy is improved, but latency increases

Engineering Contradiction:

Improvekey press detection accuracyVSAvoidscan latency

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Contact-based switches continuously monitor for key press events and generate wake signals in advance. When a wake signal is detected, the system immediately triggers a targeted scan of the corresponding subarray, eliminating the need for continuous scanning and reducing latency while maintaining detection accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The keyboard is divided into multiple subarrays, allowing the system to scan only the specific subarray where a wake signal was detected rather than scanning the entire keyboard. This segmentation reduces scan time and latency while maintaining comprehensive coverage.

Inventive Principle:

Principle #1Segmentation

3Reliability

If all subarrays are scanned, then key press detection completeness is improved, but power consumption increases

Engineering Contradiction:

Improvedetection completenessVSAvoidscanning power

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The keyboard matrix is segmented into multiple subarrays, enabling the system to scan only the specific subarray where a wake signal was detected. This selective scanning maintains detection completeness for the active region while significantly reducing power consumption compared to scanning all subarrays.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of scanning all subarrays continuously, the system performs partial scanning only of the subarray containing the active key press. This partial action is sufficient to detect the key press accurately while avoiding the excessive power consumption of full-array scanning.

Inventive Principle:

Principle #16Partial or excessive action

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 hybrid switch system enhances reliability and power efficiency by using contact-based switches for low-power mode and contactless switches for active mode, reducing power consumption and latency, and improving key press detection accuracy.

Implementation Method 1

a second type of key switch configured to generate a second signal when the depressible element is activated... the second type of key switch is an optical key switch

Methodology Applied

Scientific EffectOptical detection: Photoelectric Effect

Data Source

PatentUS12119187B1Partial scanning in a hybrid switch array

Publication Date: 2024.10.15 LOGITECH EUROPE SA

AI summary

A keyboard system including a plurality of hybrid key structures configured in an array of subarrays, each of the plurality of hybrid key structures configured within a subarray and including a depressible element, a first type of key switch configured to generate a first signal when the depressible element is activated, a second type of key switch configured to generate a second signal when the depressible element is activated, and processor(s) configured to: receive a first signal from an activated hybrid key structure when its corresponding depressible element is activated; determine a corresponding subarray that the activated hybrid key structure is configured within; scan the corresponding subarray for a generated second signal; detect the generated second signal from the corresponding subarray; identify the activated hybrid key structure based on the detected, generated second signal; and register a key press for the identified activated hybrid key structure.