The main advantage of the Mini COB/COG solution is that it can achieve ultra-thin design, ultra-fine partitioning and flexible display, etc., while the technical difficulties lie in product rework, product light and color uniformity at low current, and large-board packaging flatness.
The secret of Nationstar Mini COB/COG is to optimize the packaging process and die-bonding technology to achieve ultra-thin design and fine partitioning, so as to achieve better dynamic effects and flexible special-shaped display.
The features of Nationstar Mini COB devices include: ①Large light-emitting angle, light mixing distance ≤2mm, uniform light field distribution; ②High extraction rate of light and high uniformity of brightness and color; ③Special film-coated packaging, thin colloid and high flatness; ④ High reliability, resistant to cold and thermal shocks 1000 times; ⑤Various substrates are available.
For the application of OD 0-2mm, Nationstar provides Mini COB devices, and adopts the integrated design of thin multi-layer BT board to achieve high air tightness, high precision and high density flip-chip welding. According to the customer use and overall plan, Nationstar can achieve a balance between Pitch 1-4mm and OD 0-2mm.
In the flexible backlight part, Nationstar has also explored with customers and launched application cases. According to reports, the Nationstar Mini COB flexible backlight solution uses PI (polyimide) base film flexible circuit board, which is suitable for thinner and lighter design requirements; the product has high flexibility, can match the inner surface of 1500R, and can also be used with hard boards. Quite stable welding effect; in addition, after 2000 times of thermal shock, the colloid has no cracking, and the reliability is very high.
For the OD 0-1mm application, Nationstar cooperates with manufacturers of glass substrates to develop Mini COG devices. It has been verified that the product achieves excellent heat resistance, heat dissipation performance and high light extraction rate; at the same time, the material properties are stable, the warpage is low, and the light output consistency is good; for large-area package sizes, the Mini COG solution can reduce splicing and achieve lower module cost.
Ye Yun said that the National Star Mini COB/COG solution is recommended for small and medium-sized applications, as well as notebook and vehicle panel lights, and the application prospects are very broad. At present, the main applications of Nationstar Mini COB devices include: 15.6/16/17.3-inch laptops and 13.3-inch tablets. Mini COG devices have been used in 13.6-inch products.
In the future, the National Star Mini COB/COG solution will focus on five key breakthroughs in the design and development of high-precision multi-layer substrates, large-stroke high-precision die bonding process, Mini flip-chip solder paste welding process, AOI online inspection and repair technology, and large-area packaging process. Technology, driven by innovation, promotes the continuous maturity of Mini COB/COG technology.
Summary: At present, the Mini LED backlight industry is still on the eve of mass production, and the standardization of products and the sorting out of supply and demand relations need to be promoted by the industry chain. As one of the forces that cannot be ignored, Nationstar is actively concentrating its industrial advantages on the basis of ready technical solutions, and is working with its peers and upstream and downstream supporting manufacturers to promote the industrialization of MiniLED backlight technology. Therefore, the large-scale volume of Mini LED backlight products can be waited for.