Magnetic Keyboard Sensor Design for Thin Profile and High Sensitivity
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Solution Overview
Problem
Existing key input apparatuses using magnetic sensors struggle to achieve a significant change in resistance value while maintaining thinness, making it difficult to customize operability to user preferences.
Innovation Solution
A key input apparatus design featuring a movable key top, substrates with magnetic field generation and detection units, and an adhesion unit with a soft magnetic material, where the magnetic field generation unit is positioned to generate a magnetic field orthogonal to the key top's movement, allowing for increased change in resistance value and reduced thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the thickness of rubber domes is reduced to make the keyboard thinner, then the thickness of the keyboard is reduced, but the rubber dome buckling properties worsen and the click sensation given to the user declines
Solution Approach 1:
The patent replaces the mechanical rubber dome system with a magnetic field-based detection system. A magnetic sensor detects the position of a magnetic body attached to the key top, eliminating the need for rubber domes while maintaining key press detection functionality and enabling thinner keyboard design.
Solution Approach 2:
The patent changes the detection parameter from mechanical deformation (rubber dome buckling) to magnetic field interaction. By detecting changes in magnetic field strength or position through the magnetic sensor, the system achieves reliable key press detection without relying on rubber dome mechanical properties.
2Measurement precision
If the distance between magnets and magnetic materials is reduced to increase resistance value change, then the sensitivity increases, but the keyboard thickness is reduced
Solution Approach 1:
The patent uses thin flexible substrates to mount the magnetic sensor and magnetic body in close proximity, enabling high sensitivity detection while maintaining a thin overall keyboard structure. The flexible nature allows precise positioning of magnetic components.
Solution Approach 2:
The patent optimizes the magnetic field interaction parameters by adjusting the strength, size, and positioning of magnets and magnetic materials to achieve sufficient resistance value change within a thin profile constraint.
3Length of moving object
If the stroke amount is reduced to enable thinner keyboard, then the keyboard thickness is reduced, but the input apparatus operability is compromised
Solution Approach 1:
The patent replaces mechanical stroke-based input with magnetic field-based position detection. The magnetic sensor can detect key press states with minimal physical displacement, maintaining operational reliability while enabling thinner keyboard design.
Solution Approach 2:
The patent changes the operational parameter from mechanical stroke distance to magnetic field interaction strength. By detecting magnetic field changes at minimal displacement, the system maintains ease of operation with reduced stroke requirements.
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 design enhances the absolute change in resistance value, enabling thinner keyboards with improved customization options for user-specific operability.
Implementation Method 1
a magnetoresistive effect element and a plurality of magnets provided on a substrate, a support body composed of an elastic material covering the magnetoresistive effect element and the magnets, and a ferromagnetic material embedded in the support body. In this input apparatus, a zero magnetic field region is formed on the substrate by alternating the N-poles and S-pole of the magnets, the magnetoresistive effect element is positioned within the zero magnetic field region on the substrate, and the support body, is provided such that the ferromagnetic material is positioned directly over the magnetoresistive effect element. Furthermore, when the ferromagnetic material is displaced by operation of the support body, a change in the distribution of the magnetic field strength on the substrate is caused, and the resistance value of the magnetoresistive effect element changes in accordance with this change in the distribution of the magnetic field strength.
Implementation Method 2
an adhesion unit comprising a soft magnetic material, which is capable of adhering to the magnetic field generation unit
Data Source
AI summary
A key input apparatus includes a key top capable of moving up and down through a pressing operation; a first substrate, which includes a first surface, which is positioned on the key top side, and a second surface, which is opposite to the first surface, and the first substrate supports the key top and is provided to be movable up and down along with the key top; a second substrate, which is provided between the key top and the first substrate in the direction of the up-and-down movement of the key top, and the second substrate includes a first surface, which is positioned on the first substrate side, and a second surface, which is opposite to the first surface; a magnetic field generation unit; a magnetic sensor unit, which includes a magnetic detection element that detects a magnetic field generated from the magnetic field generation unit; and an adhesion unit, which includes a soft magnetic material capable of adhering to the magnetic field generation unit. The magnetic sensor unit and the adhesion unit are provided on one of the first surface of the first substrate and the first surface of the second substrate, and the magnetic field generation unit is provided on the other of the first surface of the first substrate and the first surface of the second substrate, opposite to the adhesion unit.