Pressure-Sensitive Keyboard Switch for Multi-Level Press Detection
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Solution Overview
Problem
Mechanical switches in keyboards lack the ability to generate switch signals for states other than pressed and unpressed, limiting their functionality and flexibility.
Innovation Solution
A pressure sensitive switch device comprising a first membrane, a first conductive wire, a second conductive wire, a pressure sensitive layer, a supporting plate, and an elastic body, where the pressure sensitive layer contacts both conductive wires and alters electrical resistance with pressing force, enabling generation of switch signals corresponding to varying pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanical switches are used in keyboards, then the structure is simple and reliable, but the switch can only detect pressed and unpressed states without providing signals for intermediate pressure states
Solution Approach 1:
The patent replaces the traditional mechanical switch contact system with a capacitive sensing system. The conductive wires and pressure-sensitive layer form a capacitive structure that detects pressure through electrical field changes rather than mechanical contact, enabling multi-state detection while maintaining structural simplicity
Solution Approach 2:
The patent utilizes changes in electrical parameters (capacitance, resistance) of the pressure-sensitive layer in response to varying pressure forces. By monitoring these electrical parameter variations, the system can distinguish between different pressure states (lightly pressed, heavily pressed, held, released) without requiring complex mechanical components
2Strength
If multiple membrane layers are used to protect conductive wires, then the structural integrity and protection are improved, but the overall thickness increases and material usage increases
Solution Approach 1:
The patent merges the protective membrane function with the conductive wire substrate into a single integrated layer. The conductive wires are disposed directly on the membrane, eliminating the need for separate protective layers and reducing overall device thickness while maintaining structural integrity
Solution Approach 2:
The membrane layer serves multiple functions simultaneously: it provides mechanical protection for the conductive wires, acts as a structural support substrate, and enables the capacitive sensing function when combined with the pressure-sensitive layer. This multi-functionality reduces the need for additional dedicated components
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
Enables generation of switch signals between pressed and unpressed states, enhancing keyboard key flexibility and user experience by utilizing a piezoelectric material in the pressure sensitive layer and minimizing membrane layers for reduced thickness and material usage.
Implementation Method 1
The pressure sensitive layer includes a piezoelectric material... when the protruding portion of the elastic body is pressed toward the pressure sensitive layer, an electrical resistance value of the pressure sensitive layer will alter with the pressing force
Data Source
AI summary
A pressure sensitive switch device includes a first membrane, a first conductive wire, a second conductive wire, a second membrane, a pressure sensitive layer, a supporting plate, and an elastic body. The second conductive wire is disposed on the first membrane and separated from the first conductive wire. The pressure sensitive layer is disposed on the second membrane and contact to the first conductive wire and the second conductive wire. The first conductive wire is electrically connected to the second conductive wire by the pressure sensitive layer. The supporting plate is located below the first membrane and has a groove. The elastic body is located over the pressure sensitive layer. The elastic body includes a deformation portion and a protruding portion. The deformation portion is configured to generate deformation to drive the protruding portion to move.