Keypad Carrier With Conductive Traces For Compact Switch Assembly
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Solution Overview
Problem
Portable electronic devices face challenges in reducing their size due to the bulkiness caused by electrical switch assemblies soldered to circuit boards, which increases their dimensional envelope.
Innovation Solution
The use of collapsible dome switches with a carrier that couples to the circuit board via conductive traces and flexible fingers, eliminating the need for fasteners like solder, allowing for a frictional or interference fit, and utilizing Laser Direct Structuring for conductive contacts and traces on a plastic carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical switch assemblies are soldered to circuit boards, then reliable electrical connection is achieved, but the dimensional envelope of the electronic device increases
Solution Approach 1:
The patent extracts the soldering process and replaces it with a mechanical insertion method. The electrical switch assembly is designed to be inserted directly into the circuit board without soldering, removing the harmful effect of increased dimensional envelope while maintaining electrical connection reliability through alternative means (mechanical contact and conductive pathways).
Solution Approach 2:
The patent replaces the thermal-mechanical soldering system with a purely mechanical insertion system. The electrical switch assembly includes contact elements that mechanically engage with corresponding receptacles on the circuit board, substituting the solder joint function with a mechanical-electrical contact system that achieves reliable connection without the space-consuming soldering process.
2Ease of operation
If physical keys with electrical switch assemblies are used, then input functionality is achieved, but assembly complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the electrical switch assembly with the key cap into a single integrated unit. The contact elements are built into the key cap structure itself, eliminating the need for separate assembly steps and reducing overall device complexity while maintaining full input functionality.
Solution Approach 2:
The electrical switch assembly is designed to be self-contained within the key cap, with conductive pathways and contact elements that automatically engage with the circuit board upon insertion. This self-service design eliminates the need for external soldering or additional assembly operations, reducing manufacturing complexity.
3Strength
If soldering is used to attach electrical switch assemblies, then strong mechanical and electrical connection is achieved, but manufacturing time and cost increase
Solution Approach 1:
The patent incorporates the electrical connection pathways and contact elements into the key cap during the molding process, before final assembly. This preliminary action ensures that the electrical switch assembly is pre-configured with all necessary conductive elements, allowing for rapid insertion and connection without time-consuming soldering operations while maintaining strong mechanical and electrical bonds.
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
This solution reduces the overall size of the electronic device by eliminating the need for fasteners, lowering assembly costs, and facilitating a smaller dimensional envelope without compromising the functionality of the keypad apparatus.
Implementation Method 1
An electrical switch apparatus disclosed herein is electrically coupled to a circuit board to generate an electrical signal when a key associated with the electrical switch is activated. More specifically, the dome switch collapses toward a conductive contact formed or printed on the carrier.
Implementation Method 2
the carrier may be at least partially disposed in a recess or cavity of a circuit board. The flexible fingers provide a spring bias that produces a force normal to a point of contact between the fingers and the circuit board when the carrier is coupled to the circuit board.
Data Source
AI summary
A keypad apparatus and related methods are disclosed herein. An example keypad apparatus includes an electrical switch and a carrier composed of a plastic resin. The carrier has conductive traces printed thereon to couple the electrical switch to a circuit board via interference.