Capacitive Keyboard Key Switch with Mechanical and Proximity Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current user input systems, particularly keyboards, face challenges in detecting touch events with low latency and sensitivity to hover, contact, and pressure, especially in real-world, virtual reality, and augmented reality settings, as they often require physical contact and struggle with non-contact touch detection.
Innovation Solution
The implementation of capacitive sensors using a multiplexing scheme based on orthogonal signaling, such as frequency-division multiplexing (FDM) or code-division multiplexing (CDM), which allows for the detection of touch events without physical contact by measuring changes in capacitance through row and column conductors, enabling low-latency and high-update-rate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mechanical switches are used for keyboard input, then physical contact detection is reliable, but non-contact hover detection capability is lost and latency increases
Solution Approach 1:
The patent combines mechanical switch actuation detection with capacitive sensing capabilities into a single key switch assembly. The mechanical switch provides reliable contact detection while the capacitive sensors (transmitter and receiver conductors) enable hover detection and pressure measurement, allowing the system to maintain reliability across both contact and non-contact interaction modes
Solution Approach 2:
The key switch is designed to perform multiple functions: mechanical actuation detection for traditional key presses, capacitive hover detection for non-contact interaction, and pressure sensitivity for force measurement. This multi-functional design allows the keyboard to adapt to various input methods including typing, gaming, and virtual reality applications
2Measurement precision
If capacitive sensors with multiplexing scheme are implemented, then hover and non-contact touch detection sensitivity is improved, but device complexity increases
Solution Approach 1:
The capacitive sensing system is segmented into row conductors and column conductors that form a grid pattern across the keyboard surface. This segmentation allows for localized hover detection at each key position while sharing the sensing infrastructure across multiple keys, improving measurement precision without proportionally increasing overall system complexity
Solution Approach 2:
The patent uses multiplexing schemes where row and column conductors act as intermediaries to detect capacitive changes. By sequentially activating rows and columns and measuring the resulting capacitive coupling, the system achieves high-resolution hover detection while reducing the number of direct sensor connections needed, thereby managing device complexity
3Device complexity
If mechanical key switches are used, then structural simplicity is maintained, but update rate and latency performance deteriorate
Solution Approach 1:
The patent replaces purely mechanical detection with a hybrid system that uses capacitive sensing to detect key press events. The capacitive sensors can detect changes in capacitance caused by finger approach, contact, and pressure, providing faster update rates and lower latency compared to traditional mechanical switches while maintaining a relatively simple overall structure
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
This solution enables the detection of touch events with very low latency, allowing for sensitive and robust measurements of hover, contact, and pressure, even without physical contact, enhancing user input systems' performance in various reality settings and facilitating economical manufacturing.
Implementation Method 1
capacitive sensors using a multiplexing scheme based on orthogonal signaling... allows for the detection of touch events without physical contact by measuring changes in capacitance
Data Source
AI summary
A key switch implements a receiving switch conductor and transmitting switch conductor in the key switch. Depressing the key switch will cause the receiving switch conductor and transmitting switch conductor to approach each other. The approach of a finger and movement of the key switch can be detected using the receiving switch conductor and the transmitting switch conductor.