Curved Keypad Key Cap Segmentation for Durability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional handheld electronic devices with curved keypads face issues of key member susceptibility to damage and molding challenges due to thin edges, which can lead to structural weaknesses and manufacturing difficulties.
Innovation Solution
A keypad design featuring key caps with uniform thickness and a curved shape, aligned with a flexible printed circuit board and dome supports, ensuring consistent contact and resistance to wear, while allowing for ergonomic operation and easy actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If key members are molded with decreasing thickness from inner edge to outer edge to achieve curved shape, then ergonomic operation is improved, but structural strength and durability deteriorate
Solution Approach 1:
The key member is divided into two separate components: a key cap with uniform thickness and a key member body. The key cap provides the curved ergonomic surface for finger contact, while the key member body maintains sufficient thickness for structural strength. This segmentation allows each component to be optimized independently for its specific function.
Solution Approach 2:
The curved shape is achieved by curving the key cap in the lateral dimension rather than varying the thickness of the key member in the vertical dimension. The key cap is curved to match the contour of the device housing, providing ergonomic operation while maintaining uniform thickness for durability.
2Ease of operation
If key members have thin laterally outer edges to achieve curved shape, then ergonomic operation is improved, but manufacturing quality deteriorates due to molding issues
Solution Approach 1:
The key member is segmented into a key cap and key member body, allowing the key cap to be manufactured separately with its curved shape. This avoids the molding difficulties associated with creating thin, curved edges in a single-piece key member.
Solution Approach 2:
The curved shape and aesthetic quality are localized to the key cap portion that is visible and contacted by the user. The key member body maintains uniform thickness for manufacturability. This local differentiation of quality requirements resolves the conflict between curved shape and molding feasibility.
3Manufacturing precision
If key members have uniform thickness, then manufacturing quality and durability are improved, but curved shape for ergonomic operation is compromised
Solution Approach 1:
The key member is divided into a key cap and key member body. The key cap is manufactured with uniform thickness for molding quality and durability, while the key member body provides structural support. The key cap is then curved to achieve the ergonomic shape.
Solution Approach 2:
The curved shape is achieved by curving the key cap in the lateral dimension rather than varying thickness in the vertical dimension. This allows the key cap to have both uniform thickness and curved shape simultaneously.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A keypad for a handheld electronic device includes a dome support having a generally curved top surface, a plurality of domes, a plurality of actuators, and a plurality of key caps. A flexible printed circuit board is attached to the top of the dome support and includes a plurality of substantially flat surface portions that are associated with substantially flat surface portions of the dome support. Each of the plurality of domes is attached to a respective one of the plurality of substantially flat surface portions of the flexible printed circuit board and is aligned with a respective one of the plurality of actuators. Each of the plurality of key caps has a bottom surface that is aligned with a respective one of the plurality of actuators and substantially parallel to a respective one of the plurality of substantially flat surface portions of the flexible printed circuit board.