Segmented Adhesive Dome Overlay for Mobile Keyboard Feedback
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Solution Overview
Problem
In mobile devices, the limited space for switch panels often compromises size, tactile feedback, and audible feedback, making it difficult for users to sense switch closures and enter input effectively, especially with dome switches that require light force and small deflection.
Innovation Solution
A keyboard dome overlay structure with a plurality of dome switches, a circuit board, a main overlay, a first adhesive dab between the dome switch and the main overlay, and a second adhesive dab surrounding the first dab, enhancing tactile feedback by creating a gap that contacts the dome switch in an actuated configuration, reducing pushing force and increasing deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive layers and composite structures are incorporated with dome switches to hermetically seal them, then dust and moisture prevention is improved, but tactile and audible feedback is reduced
Solution Approach 1:
The adhesive structure is segmented into a first adhesive layer directly contacting the dome switch and a second adhesive layer surrounding the first layer, creating a hermetic seal while preserving the central deflection area for tactile feedback
Solution Approach 2:
The adhesive layers are positioned to provide hermetic sealing at the periphery while leaving the central region of the dome switch free of adhesive, allowing the local area to maintain flexibility and provide tactile feedback when actuated
2Reliability
If adhesive layers and composite structures are incorporated with dome switches, then hermetic sealing is improved, but rigidity of dome switches increases
Solution Approach 1:
The adhesive is segmented into concentric layers where the first adhesive layer provides minimal sealing and the second adhesive layer provides the primary hermetic seal, allowing the central dome region to remain flexible
Solution Approach 2:
The adhesive layers act as intermediaries that provide hermetic sealing without directly bonding to the entire dome switch surface, allowing the dome switch to deflect while maintaining the seal
3Volume of moving object
If dome switches require light force and small deflection, then space requirements are reduced, but user ability to sense switch closures is compromised
Solution Approach 1:
The dome switch is designed with a central region that has enhanced flexibility and freedom from adhesive bonding, allowing this local area to provide amplified deflection and tactile feedback when actuated, compensating for the overall compact design
Solution Approach 2:
The dome switch structure is designed to dynamically deflect under actuation force, with the adhesive-free central region allowing greater deflection range and providing tactile feedback that helps users detect switch closure in the compact configuration
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 provides enhanced tactile feedback, reducing user frustration and improving the ability to detect successful switch closure, while accommodating greater deflection and reducing the rigidity of the keyboard keys, thus improving the overall input experience.
Implementation Method 1
a first adhesive dab interposed between the dome switch and the main overlay, and a second adhesive dab applied to a surrounding region of the first adhesive dab
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
A dome overlay structure (1000,2000,3000) for a mobile device keyboard (810) includes a plurality of dome switches (100), a circuit board (105) disposed beneath the plurality of dome switches with each dome switch electrically coupled to the circuit board, a main overlay (110) disposed over the plurality of dome switches, and a first adhesive dab (115) centrally interposed between the dome switch and the main overlay with a second adhesive dab (125) surrounding the first adhesive dab. Each dome switch has a central portion (310) and a non-central portion (315). The first adhesive dab can bond the central portion of the dome switch to the main overlay. The second adhesive dab is configured to form a gap (325) between the second adhesive dab and the non-central portion of the dome switch in an unactuated configuration and configured to contact the non-central portion of the dome switch in an actuated configuration.