LED Package Lead Frame Assembly with External Wire Bonding
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Solution Overview
Problem
Conventional LED package structures face issues with increased thickness and size due to large cavities, which affect uniform illumination, and ceramic materials complicate manufacturing and increase costs.
Innovation Solution
A lead frame assembly with an insulating housing and a lead frame unit comprising a first and second lead frame portion, where the second lead frame portion is exposed outwardly for electrical connection, allowing for reduced cavity dimensions and easier manufacturing with plastic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large cavity is designed in the housing to accommodate wire binder, then wire binding operation is enabled, but the thickness of the housing and the size of the LED package structure increase
Solution Approach 1:
The patent extracts the wire binder from the cavity space by positioning it externally on the housing. The wire binder is mounted on the outer surface of the housing rather than requiring internal cavity space, thereby enabling wire binding operation without increasing housing thickness or cavity dimensions.
Solution Approach 2:
The patent transitions the wire binder from a three-dimensional internal cavity component to a two-dimensional external surface mounting. By placing the wire binder on the outer surface of the housing, the design utilizes the external surface area rather than consuming internal cavity volume, thus resolving the space conflict.
2Ease of operation
If a large cavity is designed in the housing, then wire binder can be placed, but uniform illumination is compromised after encapsulating material is filled
Solution Approach 1:
The wire binder is extracted from the cavity and positioned externally on the housing surface. This removal allows the cavity to be minimized and filled with encapsulating material that provides uniform illumination, while the wire binder remains accessible for wire binding operations on the external surface.
Solution Approach 2:
The housing surface is designed with differentiated local qualities: the outer surface provides a mounting platform for the wire binder, while the inner cavity surface is optimized for uniform light reflection and illumination. This local differentiation allows both wire binder placement and uniform illumination to coexist.
3Strength
If ceramic material is used for the housing, then structural integrity is achieved, but manufacturing process becomes troublesome and manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, difficult-to-manufacture ceramic housing with a more economical material that can be easily molded and assembled. The housing uses materials such as plastic or polymer composites that offer sufficient structural integrity for LED packages while enabling simpler, more cost-effective manufacturing processes like injection molding.
Solution Approach 2:
The housing may utilize composite materials that combine polymer matrices with reinforcing fillers or fibers to achieve the necessary structural integrity and thermal properties without the complexity and cost of ceramic materials. This composite approach provides a balance between strength and manufacturability.
4Ease of operation
If the second lead frame portion is exposed outwardly for electrical connection, then wire connection is simplified, but housing material must provide proper coverage and insulation
Solution Approach 1:
The housing material is designed with differentiated local properties: areas requiring insulation and coverage are provided with appropriate dielectric materials, while areas requiring electrical connection have the lead frame portions exposed. This local differentiation allows simplified wire connection in exposed areas while maintaining proper insulation where needed.
Solution Approach 2:
The housing acts as an intermediary structure that selectively covers and exposes different portions of the lead frame. It provides insulation and mechanical support where required while leaving specific lead frame portions exposed for electrical connection, thus mediating between the conflicting requirements of insulation and accessibility.
Data Source
AI summary
A package structure is adapted for mounting at least one light emitting diode (LED) die. The package structure includes an insulating housing having a top surface that is formed with a cavity, and a lead frame unit. The lead frame unit includes a first lead frame portion and a second lead frame portion. The first lead frame portion is covered by the insulating housing, and has a die-bonding area exposed within the cavity and adapted for mounting the LED die. The second lead frame portion is covered by the insulating housing, and has a conductive surface exposed outwardly of the top surface of the insulating housing and adapted for electrical connection with an end of a conductive wire.