Keypad Assembly Sealed Dome Overlay for Edge Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mobile devices with QWERTY keypads face spatial constraints, leading to domes being positioned near the edge of the circuit board, making them susceptible to contamination and potentially misaligned, which degrades tactile feedback.
Innovation Solution
A keypad assembly with a dome overlay and interlocking components that create a sealed environment, allowing domes to be placed near the edge while protecting them from contaminants and maintaining alignment with keys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If domes are positioned near the edge of the circuit board to accommodate QWERTY keypad in limited space, then the device can fit more keys, but the domes become susceptible to contamination from external contaminants
Solution Approach 1:
The patent employs a flexible membrane overlay that spans across the keypad surface and extends beyond the edge of the circuit board. This membrane acts as a protective barrier that seals the domes positioned near the board edge, preventing contaminants from reaching them while allowing the domes to function normally under the membrane coverage.
Solution Approach 2:
The flexible membrane serves as an intermediary element between the external environment and the domes. It transmits the tactile feedback from key presses to the domes while simultaneously blocking contaminants from reaching the domes, thus mediating between the need for edge positioning and contamination protection.
2Object-affected harmful factors
If domes are moved towards the center of the circuit board to protect from contaminants, then contamination resistance improves, but the domes become misaligned with the keys on the edges
Solution Approach 1:
The flexible membrane is designed to extend beyond the circuit board edge, creating a sealed environment that allows domes to be positioned near the board edge without contamination risk. This maintains precise alignment between domes and keys while providing contamination protection.
3Area of stationary object
If domes are positioned near the edge of the circuit board, then spatial constraints are satisfied, but tactile feedback performance degrades due to misalignment
Solution Approach 1:
The flexible membrane overlay creates a sealed environment that enables precise dome-key alignment even when domes are positioned near the circuit board edge. This maintains tactile feedback performance while maximizing the use of available circuit board area.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A keypad assembly (300) is described herein in which the keypad assembly (300) includes a substrate (200) and a plurality of domes (302) positioned on the substrate (200) and configured to translate operator action into a corresponding input for a machine. The keypad assembly (300) also includes a dome overlay (330) positioned over the domes (302) and the substrate (200) in which the dome overlay (330) can create a sealed environment for the substrate (200) and the domes (302). A light guide (320) that directs light in the keypad assembly (300) and an interlocking component (335) coupled to the light guide (320) can also be part of the keypad assembly (300). In one arrangement, the interlocking component (335) can selectively compress the dome overlay (330) to assist in the creation of the sealed environment. In another arrangement, the interlocking component (335) can compress the dome overlay (330) by bending the dome overlay (330) at an edge (210) of the substrate (200).