Elastomeric Keypad Valve for Noise Suppression
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Solution Overview
Problem
Existing elastomeric keypads typically have lower sound intensity during the push down event due to dome deformation, while the push up event is louder and often noisy due to collisions, which is undesirable for user experience.
Innovation Solution
Incorporating a passive check valve, preferably a Tesla Valve, in the compensating channels to restrict fluid flow during the return of the elastomeric dome, ensuring laminar flow during depression and turbulent flow during release, thereby suppressing the sound intensity of the push up event.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If compensating channels are provided to enable fluid flow from the chamber while the elastomeric dome collapses and to the chamber while the elastomeric dome releases, then the dome can return to its neutral position, but the push up event generates high sound intensity due to collision of the dome with the key cap or housing
Solution Approach 1:
The patent changes the flow resistance parameter of the compensating channel by incorporating a valve arrangement. The valve has different flow characteristics for opposite directions: low resistance during push down (allowing smooth dome collapse) and high resistance during push up (suppressing dome return speed and collision noise). This parameter change resolves the contradiction by making the channel properties direction-dependent.
Solution Approach 2:
The valve arrangement acts as an intermediary element inserted into the compensating channel. It mediates the fluid flow between the chamber and the external environment, selectively restricting flow during the push up event. This intermediary component enables the system to achieve both smooth dome collapse and reduced collision noise by controlling the timing and characteristics of fluid flow.
2Ease of operation
If the compensating channel allows unrestricted fluid flow during dome collapse, then the dome can deform smoothly, but the sound intensity of the push down event remains lower than desired
Solution Approach 1:
The valve arrangement modifies the flow resistance parameter dynamically based on flow direction. During push down, the valve maintains low resistance to allow smooth dome deformation, while during push up, it increases resistance to suppress collision noise. This directional parameter control resolves the contradiction between smooth deformation and sound intensity.
3Object-generated harmful factors
If a valve arrangement is added to the compensating channel to restrict fluid flow during dome return, then the sound intensity of the push up event is reduced, but the device complexity increases
Solution Approach 1:
The valve arrangement is designed as a passive check valve that automatically responds to flow direction without requiring external control mechanisms. The valve geometry itself provides the flow restriction function through its asymmetric structure, eliminating the need for additional actuators, sensors, or control circuits. This self-service approach minimizes the increase in device complexity while achieving the desired noise reduction.
Solution Approach 2:
The invention uses fluid dynamics principles to achieve noise control. The compensating channel with valve arrangement utilizes air pressure differentials created during dome collapse and release to automatically regulate flow. The pneumatic/hydraulic mechanism of the passive valve provides the required flow restriction during push up without mechanical complexity, resolving the contradiction between noise reduction and device simplicity.
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
Enhances the sound intensity of the push down event while reducing noise during the push up event, improving the overall keypad sound characteristics without increasing manufacturing complexity or costs.
Implementation Method 1
generating fluid restrictions while the fluid returns to said chamber, while providing substantially laminar flow of fluid while said elastomeric dome collapses
Implementation Method 2
providing substantially laminar flow of fluid while said elastomeric dome collapses
Implementation Method 3
an array of elastomeric domes, each defining a chamber
Data Source
Figure 1~2
Figure 3a~5b
AI summary
The present invention relates to an elastomeric keypad (1) having at least one key (3) comprising an elastomeric dome (41) defining a chamber (42) and provided inside with an activating means (43), an activation means (44) cooperating with said activation means (44), and at least one compensating channel (48) opening at said chamber (42) to enable for a flow of fluid from said chamber (42), while said elastomeric dome (41) collapses, and to said chamber (42), while said elastomeric dome (41) releases. In order to suppress the sound intensity of the push up event, at least one of said compensating channels (48) comprises at least one valve arrangement (5) generating fluid restrictions while the fluid returns to said chamber (42). Preferably said valve arrangement (5) has a form of a Tesla Valve.