Electropermanent Magnet Key Switch for Adjustable Tactile Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing keyboard systems have limitations in providing multiple default positions for keys and variable tactile feedback, as they rely on rubber dome structures that restrict key design and user experience in terms of thickness and tactile sensation.
Innovation Solution
The use of electropermanent magnets (EPMs) in key switch assemblies allows for magnetic force to return keys to their neutral position, enabling multiple default positions and adjustable tactile feedback by varying the magnetic field strength, which can be controlled to simulate deeper keystrokes in a thinner form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rubber dome structures are used in keyboard keys, then the keys have a simple structure and are easy to manufacture, but the keys cannot provide multiple default positions and have limited tactile feedback
Solution Approach 1:
The patent replaces the traditional mechanical rubber dome structure with an electropermanent magnet system that uses magnetic fields to control key position. The magnet can be electrically switched to provide upward or downward magnetic forces, enabling multiple stable positions (upward, downward, and intermediate positions) without complex mechanical components.
Solution Approach 2:
The patent changes the physical state parameter of the magnetic field by applying or removing electrical current to the coil. This allows the electropermanent magnet to switch between different magnetic states (attracting or repelling), thereby controlling the key's position and providing variable tactile feedback without mechanical movement.
2Adaptability or versatility
If electropermanent magnets are used to provide magnetic force, then multiple default positions and adjustable tactile feedback are enabled, but the device complexity increases
Solution Approach 1:
The electropermanent magnet assembly serves multiple functions: it provides upward magnetic force for key return, downward magnetic force for simulated deeper keystroke, and can be switched off completely. This single component replaces what would traditionally require multiple separate mechanical elements, reducing overall system complexity despite the advanced functionality.
Solution Approach 2:
The patent introduces a ferromagnetic flange as an intermediary component that couples the magnetic force from the electropermanent magnet to the scissor plate mechanism. This flange acts as a magnetic coupling element that translates the magnetic field changes into mechanical motion, simplifying the direct connection between the magnet and the key mechanism.
3Ease of operation
If the magnetic field strength is varied to simulate deeper keystrokes, then tactile feedback is enhanced, but the key thickness must increase
Solution Approach 1:
The patent uses periodic or pulsed electrical current applied to the coil to generate the necessary magnetic field strength temporarily. This allows the magnet to provide strong magnetic force only when needed (during key actuation), rather than requiring a continuously strong magnet that would increase the assembly thickness. The magnetic field is activated only during the keystroke event.
4Reliability
If the magnetic field is disabled to prevent inadvertent keystrokes, then key control is improved, but the key cannot return to neutral position
Solution Approach 1:
The system applies a preliminary magnetic pulse to the electropermanent magnet before the key needs to return to neutral position. This pre-activation ensures that the magnetic force is already present and ready to immediately push the key upward, preventing any delay or failure in the key return function even when the magnetic field is otherwise disabled for preventing inadvertent keystrokes.
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 enhances user experience by providing consistent tactile feedback and adjustable resistance, allowing keys to feel as if they travel further into the keyboard without increasing thickness, and prevents inadvertent keystrokes by disabling the magnetic field when needed.
Implementation Method 1
allows magnetic force to return keys to their neutral position
Implementation Method 2
The use of electropermanent magnets (EPMs) in key switch assemblies allows for magnetic force to return keys to their neutral position
Data Source
AI summary
An electropermanent magnet key assembly of an information handling system comprising an electropermanent magnet (EPM) having a low-coercivity magnet and a high-coercivity magnet, wherein the EPM is capable of an on state generating a magnetic field and an off state disabling the magnetic field, a key cap, situated atop a pair of scissor plates, capable of downward movement, via action of the scissor plates, from a raised, neutral position in which a surface of the key cap is moved to a depressed position below the neutral position, wherein the downward movement of the key assembly may record a keystroke, a flange operably connected a first scissor plate of the pair of scissor plates and extending opposite of a hinge of the first scissor plate, such that the flange is attracted toward the magnetic field of the EPM situated beneath the pair of scissor plates to urge the first scissor plate to push the key cap to the neutral position in an on state, and a spring exerting a biasing force to rotate a rocker arm toward the flange for urging the flange away from the EPM opposite to the attraction of the magnetic field of the EPM, wherein the effect of the biasing force on movement of the flange is lesser than the effect of the magnetic field generated by the EPM on movement of the flange in the on state.