Flip LED Chip Module With Pad Slots for Uniform Mini-LED Bonding
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Solution Overview
Problem
Mini LEDs face challenges in uniform light emission and bonding reliability due to small pad sizes, leading to issues like open circuits, insufficient illumination, and inconsistent color uniformity, particularly in backlight displays.
Innovation Solution
A flip LED chip module design with a substrate, flip LED chips, a first glue layer covering the chips, and a second glue layer that reduces light intensity differences, along with pad slots for improved soldering, and a specialized printing screen for efficient chip placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pad size of the chip is reduced to miniaturize the LED module, then the display precision and exquisiteness are improved, but the bonding force between the chip pad and the solder paste becomes small, leading to open circuits and insufficient illumination
Solution Approach 1:
The chip structure is segmented by introducing pad slots that divide the pad area into multiple regions, allowing the solder paste to form separate bonding zones that collectively increase the total bonding force despite the small overall pad size
Solution Approach 2:
The pad slots create local variations in the pad structure, concentrating the bonding function in specific areas where the solder paste can form stronger adhesions, thereby improving local bonding quality to compensate for the small overall pad size
2Manufacturing precision
If the hole size of the printing screen is reduced to apply solder paste on small light emitting units, then the placement precision is improved, but the solder paste fails to demold from the printing screen, affecting product yield
Solution Approach 1:
The pad slots are pre-formed on the chip pads before the solder paste application, creating predetermined demolding pathways that facilitate the release of solder paste from the printing screen holes, thereby solving the demolding difficulty while maintaining small hole sizes for precise placement
3Manufacturing precision
If the light emitting unit size is reduced to improve display effect, then the display quality is improved, but the contact area between the chip and the solder paste becomes small, reducing bonding reliability
Solution Approach 1:
The reduction in light emitting unit size is compensated by segmenting the pad structure into multiple bonding zones created by pad slots, which collectively provide sufficient contact area for reliable soldering despite the small overall chip size
Solution Approach 2:
The pad slots introduce a vertical dimension to the bonding interface by creating recessed areas, effectively increasing the bonding surface area and contact points without increasing the planar footprint of the chip
Data Source
AI summary
A flip LED chip module and a method for manufacturing LED chip module are provided. In the manufactured flip LED chip module, the second glue layer for reducing light energy is formed on the front surface of each of the flip LED chips. Therefore, the difference between the light intensity of the light along the normal direction of the flip LED chip and the light intensity of the light at the four sides of the flip LED chip can be reduced, thus improving the uniformity of the color of the light. Hence, the color of the light of the LED device manufactured by the LED chip module can be more uniform, thus improving the quality of the LED device and the user satisfaction.