Keyboard Movable Switch Mechanism for Tactility and Dome Life
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Solution Overview
Problem
Conventional keyboards, especially compact ones, suffer from poor typing tactility due to short travel distance and metal dome fatigue from excessive squeezing, leading to a shortened service life.
Innovation Solution
A key module with a movable switch mechanism incorporating an elastic member and a linkage member, where the elastic member's trigger portion passes through a metal dome to contact the circuit membrane, providing resilient tactility and preventing direct contact between the metal dome and circuit membrane, thus avoiding excessive squeezing and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a metal dome is disposed between the keycap and the circuit membrane to reduce total height, then the keyboard achieves a compact size, but the typing tactility becomes rough and poor with shorter travel distance
Solution Approach 1:
The patent introduces an elastic member as an intermediary component between the keycap and the metal dome. This elastic member includes a trigger portion that passes through the metal dome's opening to contact the conductive circuit, while the metal dome itself contacts the keycap. This intermediary arrangement allows the metal dome to provide structural support and height reduction while the elastic member provides the tactile feedback and longer travel distance needed for good typing tactility.
2Volume of moving object
If the metal dome repeatedly withstands compressive loads to activate the circuit, then the keyboard maintains compact size, but the metal dome experiences fatigue and shortened service life
Solution Approach 1:
The elastic member serves as a mediator that absorbs the repeated compressive loads during key pressing. The trigger portion of the elastic member contacts the conductive circuit to activate it, while the metal dome primarily supports the keycap structure. This distribution of functional loads reduces fatigue on the metal dome, extending its service life while maintaining the compact keyboard design.
Solution Approach 2:
The patent changes the material parameter of the elastic member to have elastic properties that allow it to deform and recover during repeated pressing. This elastic deformation absorbs the compressive energy, preventing it from being fully transmitted to the metal dome, thereby reducing metal fatigue and extending the service life of the compact keyboard structure.
3Ease of operation
If a plastic dome is used to provide longer travel distance and better typing tactility, then the typing experience is improved, but the total height of the keyboard increases
Solution Approach 1:
The patent employs a composite structure combining a metal dome and an elastic member. The metal dome provides the rigid structural support needed for compact height, while the elastic member provides the flexible deformation characteristics that enable longer travel distance and better typing tactility. This composite approach integrates the advantages of both materials while mitigating their individual disadvantages.
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 solution enhances typing tactility with a longer travel distance and extends the metal dome's service life by distributing the pressing force through the elastic member, reducing wear on the metal dome.
Implementation Method 1
an elastic member disposed on the metal dome... When the keycap is pressed, the trigger portion of the elastic member moves downwards to abut against the conductive circuit
Implementation Method 2
a metal dome disposed on a top surface of the circuit membrane... prevents the metal dome from being excessively squeezed
Data Source
AI summary
A keyboard includes a plurality of key modules. Each key module includes a baseplate, a circuit membrane disposed on the baseplate, a metal dome disposed on the circuit membrane, an elastic member disposed on the metal dome, and a keycap. The elastic member and the linkage member are configured to be a movable switch mechanism. The circuit membrane has a conductive circuit. The metal dome has an opening corresponding to the conductive circuit of the circuit membrane. A trigger portion protrudes from an underside of the elastic member. When the keycap is pressed, the trigger portion passes through the opening of the metal dome, and moves downwards to abut against the conductive circuit to induce a conducting signal. The movable switch mechanism can be made by a double injection molding method.