LED Backlight Circuit Layout for Bonding Pad Detection
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Solution Overview
Problem
Current mini LED backlight panels face issues with die bonding failures due to alignment errors during the coating process, leading to high power consumption, high side temperatures, and stress on soldering tin, which results in cold solder joints and adhesive fractures when bent.
Innovation Solution
The LED backlight module features a substrate with solder mask window areas and conductive circuits that include main and auxiliary circuits, where the auxiliary circuits intersect with the electrode wiring direction, ensuring proper bonding pad detection and reducing stress on soldering tin, and uses packaging adhesives that extend perpendicularly to the bending direction to prevent separation and fracture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the routing-wiring direction of conductive circuits is parallel to the electrode wiring direction, then the manufacturing process is simpler, but alignment errors during insulating coating cause bonding pad detection failures
Solution Approach 1:
The patent changes the routing direction of auxiliary circuits from parallel to perpendicular relative to the electrode wiring direction. This asymmetric routing ensures that the auxiliary circuits do not overlap with bonding pads during alignment errors, allowing successful detection while maintaining manufacturing simplicity.
Solution Approach 2:
The auxiliary circuits serve as intermediary elements that provide alternative detection paths. When main circuits fail detection due to alignment errors, the auxiliary circuits act as mediators to enable bonding pad detection through their perpendicular routing configuration.
2Strength
If solder paste is used for connecting light-emitting units to substrate, then the connection is initially strong, but the brittle soldering tin causes cold solder joints under stress
Solution Approach 1:
The patent employs a composite connection structure combining conductive circuits, auxiliary circuits, and packaging adhesives. This composite approach replaces reliance on brittle solder paste with a more resilient multi-material system that maintains electrical connectivity and mechanical strength under bending stress.
Solution Approach 2:
The auxiliary circuits are designed with extended lengths and perpendicular routing to beforehand cushion against alignment errors and mechanical stress. This preemptive design prevents cold solder joints by creating stress-resistant pathways before failures occur.
3Ease of manufacture
If packaging adhesive is applied without considering bending direction, then the application process is simpler, but the adhesive fractures when the substrate is bent
Solution Approach 1:
The patent applies packaging adhesive asymmetrically, concentrating it along the bending direction rather than distributing it uniformly. This asymmetric application prevents adhesive fracture by positioning the adhesive to accommodate the bending stress pattern, maintaining bonding strength while keeping the application process relatively simple.
Data Source
AI summary
Some embodiments of the present disclosure disclose an LED backlight module and a display device, a plurality of light-emitting units are distributed on a substrate of the LED backlight module, and the surface of the substrate is provided with a plurality of solder mask window areas for the plurality of light-emitting units to abut against, and a conductive circuit connecting two adjacent light-emitting units includes a main circuit and an auxiliary circuit; a remaining portion of the substrate except for the solder mask window area is coated with an insulating material, an alignment error in the coating process causes the reserved solder mask window area to be covered and an actual solder mask window area to shift, since the auxiliary circuit passes through the solder mask window area and a routing-wiring direction is intersected the connecting-wiring direction of the two electrodes of the light-emitting units.