Augmented LED Array Assembly Using Flexible PCB Contact Bridges

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Solution Overview

Problem

The existing methods for assembling high-lumen LED arrays, such as those used in automotive front lighting, are costly and difficult due to the need for forming numerous wire bonds in confined spaces, which complicates the accurate electrical connection of micro-LED arrays to printed circuit boards (PCBs).

Innovation Solution

The implementation of an augmented LED array assembly that includes a hybridized device with a micro-LED array mounted on a driver IC and a flexible PCB with contact bridges, allowing for direct bonding of driver IC contact pads to the PCB, eliminating the need for wire bonds and simplifying the assembly process by using a planar contact bridge carrier for handling and electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wire bonds are used to connect micro-LED arrays to PCBs, then electrical connections can be established, but the assembly process becomes costly and difficult due to the need for forming numerous wire bonds in confined spaces

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidassembly process ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the wire bonding process from the assembly and replaces it with direct bonding of contact pads. The flexible PCB with integrated contact bridges eliminates the need for separate wire bonds, simplifying the manufacturing process while maintaining electrical connection reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The flexible PCB with contact bridges serves as an intermediary component between the micro-LED array and the rigid PCB. This mediator provides direct bonding surfaces that eliminate the need for wire bonds, making the assembly process easier while ensuring reliable electrical connections.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If numerous wire bonds are formed in confined spaces, then electrical connections are achieved, but the risk of damage to the LED array increases

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoiddamage risk to LED array

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the wire bonding operation from the confined space around the micro-LED array. By using direct contact pad bonding on the flexible PCB, the process eliminates the mechanical manipulation and potential damage associated with wire bonding in tight spaces.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The flexible PCB is segmented into multiple contact bridges that can be independently formed and bonded. This segmentation allows each contact bridge to be precisely positioned and bonded separately, reducing the risk of damage to the LED array while establishing reliable electrical connections.

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If direct bonding of contact pads is used, then the assembly process is simplified and costs are reduced, but precise alignment must be achieved

Engineering Contradiction:

Improveassembly process easeVSAvoidcontact pad alignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The flexible PCB is pre-formed with contact bridges and contact pads in precise positions before bonding to the micro-LED array. This preliminary preparation ensures that alignment is achieved during the bonding process itself, simplifying the overall assembly while maintaining the required manufacturing precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The flexible PCB material allows for parameter changes in terms of flexibility and conformability, enabling precise alignment of contact pads with the micro-LED array contact pads during bonding. The flexibility accommodates slight variations in positioning while maintaining precise electrical connections.

Inventive Principle:

Principle #35Parameter changes

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 simplifies the assembly process, reduces the risk of damage to the LED array, and allows for precise alignment and easy soldering of connections, thereby reducing costs and improving the efficiency of LED array integration into lighting circuits.

Implementation Method 1

Each of the driver IC contact pads is bonded to a corresponding one of the first contact pads of the flexible PCB

Methodology Applied

Scientific EffectBonding: Welding

Data Source

PatentUS20230156920A1Method Of Manufacturing An Augmented LED Array Assembly

Publication Date: 2023.05.18 LUMILEDS SINGAPORE PTE LTD

AI summary

An LED array assembly may include a hybridized device and a flexible PCB. The hybridized device may include a micro-LED array mounted on a driver IC. The driver IC may include driver IC contact pads on a top surface of the driver IC. The flexible PCB may have a bottom surface, first contact pads on the bottom surface, second contact pads on the bottom surface, and contact bridges. Each of the contact bridges extends from one of the first contact pads to one of the second contact pads. Each of the driver IC contact pads is bonded to a corresponding one of the first contact pads of the flexible PCB.