Flexible Lead Frame Assembly for Tolerance Compensation
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Solution Overview
Problem
Rigid lead frames in electronic assemblies lack flexibility to accommodate tolerance variations due to manufacturing processes and thermal expansion, leading to inconsistent connections and potential stress.
Innovation Solution
A flexible lead frame assembly with multiple sub-lead frames connected by interconnects featuring arc portions that allow for relative movement, along with exposed terminals and segments that provide housing without overmolding the interconnects, enabling transverse movement and compensation for tolerance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid lead frames are used to provide stable connections, then connection stability is improved, but flexibility to accommodate tolerance variations deteriorates
Solution Approach 1:
The lead frame is divided into multiple segments (first lead frame, second lead frame, third lead frame) connected by interconnects. This segmentation allows each segment to maintain relative stability while the interconnects provide the necessary flexibility to accommodate tolerance variations between components, resolving the contradiction between connection stability and adaptability.
Solution Approach 2:
The interconnects are designed with arc portions that can deflect dynamically to accommodate relative movement between lead frame segments. This dynamic capability allows the rigid segments to maintain stable connections while the flexible interconnects adapt to tolerance variations, simultaneously achieving both connection stability and flexibility.
2Strength
If rigid lead frames are used to maintain structural integrity, then structural strength is improved, but allowance for dimensional fluctuations deteriorates
Solution Approach 1:
By segmenting the lead frame into multiple rigid sections connected by flexible interconnects, the structure maintains overall integrity while allowing local dimensional adjustments. Each rigid segment preserves structural strength, while the interconnects accommodate dimensional fluctuations from thermal expansion and manufacturing tolerances.
Solution Approach 2:
The interconnects incorporate arc portions that function as flexible elements between rigid lead frame segments. These flexible interconnects allow the rigid segments to maintain structural integrity while accommodating dimensional fluctuations through controlled deflection of the arc portions.
3Manufacturing precision
If rigid lead frames are used to ensure precise component positioning, then positioning precision is improved, but compensation for thermal expansion deteriorates
Solution Approach 1:
The interconnects with arc portions provide dynamic adjustment capability that allows the lead frame assembly to compensate for thermal expansion while maintaining precise component positioning. The rigid segments ensure manufacturing precision, while the flexible interconnects dynamically adjust to thermal dimension changes.
Solution Approach 2:
The arc portions of the interconnects are designed with specific geometric parameters that allow controlled deflection to compensate for thermal expansion. By carefully designing the arc radius, thickness, and material properties, the interconnects can compensate for thermal dimension changes while the rigid segments maintain precise component positioning.
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 flexible lead frame assembly effectively compensates for component location tolerances and thermal expansion, ensuring reliable connections with minimal stress and accommodating variations in component positioning.
Implementation Method 1
The first arc portion, second arc portion, and third arc portion deflect to allow for relative movement between two or more of the sub-lead frames
Data Source
AI summary
A lead frame assembly which allows for the connection of multiple individual fixed components in various locations, while alleviating tolerance concerns by having a flexible lead frame. The lead frame assembly includes several sub-lead frames, and a plurality of interconnects which connect each of the sub-lead frames together. The lead frame assembly also includes a plurality of segments, and each segment surrounds one of the sub-lead frames, to electrically isolate each sub-lead frame. Various components are electrically connected by incorporating stamped receptacles, or slot terminals, in the sub-lead frames. The interconnects along with plastic voids allow the various attached components to have tolerance flexibility relative to one another, as various components are attached to each of the slot terminals.