Top-Side Contact LED Packaging via Compression Molding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LED packaging technologies are inefficient and costly, with significant material losses and non-standard semiconductor packaging methods, leading to high manufacturing costs and limitations in shrinking LED package sizes and handling them using standard semiconductor equipment.
Innovation Solution
The method involves forming lenses over LED dies on a substrate with top-side contacts using compression molding, exposing the contacts, and removing excess silicone flash layers using abrasive particles in a stream of air to create a more efficient and cost-effective interface for packaging, enabling smaller LED package sizes and standard semiconductor processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional LED packaging methods are used with carrier substrates and through-hole vias, then electrical connections can be established, but manufacturing complexity increases and adaptability decreases for different array designs
Solution Approach 1:
The patent divides the LED array into modular building blocks, where each block contains a subset of LED chips mounted on a carrier substrate with standardized top-side contact pads. This segmentation allows different array configurations to be created by assembling the same standardized blocks, reducing manufacturing complexity while maintaining adaptability.
Solution Approach 2:
The patent creates a universal building block design with standardized top-side contact pads that can be used across different array configurations. The same carrier substrate with LED chips and top-side pads serves multiple functions: electrical connection, mechanical support, and modular assembly unit, eliminating the need for different via configurations for different designs.
2Adaptability or versatility
If top-side contact pads are used instead of through-hole vias, then adaptability to different array designs improves, but electrical connection to power source becomes more difficult
Solution Approach 1:
The patent introduces an intermediary component - a conductive adhesive layer - that bridges the top-side contact pads on the carrier substrate with the traces on the printed circuit board. This adhesive layer with conductive particles provides both mechanical bonding and electrical connection, making the connection process as straightforward as the adhesive curing process while maintaining top-side contact accessibility.
3Ease of operation
If discrete light emitters with carrier substrates are used, then ease of handling improves, but space efficiency on printed circuit board decreases
Solution Approach 1:
The patent transitions from bottom-side mounting to top-side mounting of contact pads on the carrier substrate. This dimensional change allows the carrier substrate to be mounted directly onto the printed circuit board from the top, eliminating the need for through-hole vias and reducing the space required on the PCB, while the carrier substrate continues to provide ease of handling as a modular unit.
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 approach reduces manufacturing costs, minimizes waste, and allows for smaller LED package sizes to be handled using standard semiconductor technologies, providing a more efficient and cost-effective interface for LED dies and arrays.
Implementation Method 1
removing excess silicone flash layers using abrasive particles in a stream of air
Implementation Method 2
forming lenses over LED dies on a substrate with top-side contacts using compression molding
Data Source
Figure 1
Figure 2~4
Figure 5~6B
AI summary
Standardized photon building blocks are packaged in molded interconnect structures to form a variety of LED array products. No electrical conductors pass between the top and bottom surfaces of the substrate upon which LED dies are mounted. Microdots of highly reflective material are jetted onto the top surface. Landing pads on the top surface of the substrate are attached to contact pads disposed on the underside of a lip of the interconnect structure. In a solder reflow process, the photon building blocks self-align within the interconnect structure. Conductors in the interconnect structure are electrically coupled to the LED dies in the photon building blocks through the contact pads and landing pads. Compression molding is used to form lenses over the LED dies and leaves a flash layer of silicone covering the landing pads. The flash layer laterally above the landing pads is removed by blasting particles at the flash layer.