1. Mainstream packaging solutions for Mini LED
Currently, there are mainly three types: POB, COB, and COG
1) POB: Package on Board, a traditional packaging solution. The advantages are high maturity of the solution, reusable equipment, and low cost; the disadvantage is that the OD value is high, which limits the expansion of its application scenarios. It is mainly aimed at the mid- and low-end TV, MNT, and automotive markets. In the short term, the POB solution is dominant.
2) COB/COG: Chip on Board/Glass, a chip-level packaging solution. The advantage is that ~0 OD can be achieved, and the module is lighter and thinner; the disadvantage is that the maturity of the solution needs to be improved, new equipment investment is required, and the cost is high. In the medium and long term, the COB solution is expected to become the mainstream.
2. Finding a balance between cost and performance parameters is the focus of the current stage
The packaging link mainly achieves cost reduction by coordinating and optimizing the light output angle. Packaging is not the core link of this round of cost reduction. For the current Mini LED TV, finding a balance between cost and performance in different price ranges is the main consideration for terminal manufacturers to choose packaging solutions. COB has a more streamlined process and product structure, and can be made thinner and lighter with a low OD value, but there is still a gap in yield, industrial chain matching and cost compared with POB. From the perspective of cost reduction, the current mainstream solution is to increase the light output angle of a single LED through lenses, dispensing and other solutions, and cooperate with optimized optical solutions to reduce the overall number of LED lamp beads/chips used.
3. Midstream module link
The design of the Mini LED backlight module includes the selection of PCB board and driver IC solution. In the above disassembly of the backlight board of the 65-inch Mini LED TV, the cost of the PCB board + driver IC accounts for nearly 60%, which is the link that should be focused on in the cost reduction of the backlight module.
4. The driver IC sends drive signals and data to the display panel in the form of electrical signals
The driver IC consists of gate and source drivers. It forms instructions through analog digital/algorithm processing, and then transmits the motherboard information to each pixel by controlling the voltage to form a picture. For Mini LED backlight, the increase in the number of LED chips in series leads to insufficient voltage drop provided by a single chip, so the number of driver ICs required has increased significantly, raising the cost share of the driver IC.
5. Driver ICs are mainly supplied by Chinese mainland manufacturers, Taiwanese manufacturers and Korean manufacturers
Overall, the share of Chinese mainland manufacturers still has a lot of room for improvement. The leading companies in the TV driver IC market are Novatek Technology (20.9%) from Taiwan and LX Semicon (19.9%) from Korea. The share of leading Chinese mainland manufacturers is basically 6%-8%, with a total share of 19.3%.
6. The driver IC link mainly converts from PM to AM driving mode to achieve cost reduction
Currently, there are two main driving modes: PM (Passive Matrix) and AM (Active Matrix). At this stage, the PM solution is more widely used, but with the increase in partitions, there will be problems such as wiring difficulties and too many ICs, making it difficult to balance cost and performance. The AM driving solution adopts a lamp-driven integrated architecture, which can attach the driver IC and LED chip to the same side, and with a single-layer substrate, it can reduce the use of PCB materials and achieve cost reduction.
7. The mainstream solution for Mini LED backlight is still PCB board
PCB board stands for Printed Circuit Board, which is mainly used to build electronic circuits. PCB board and glass substrate are mainly used in TV. The full process system of PCB board industry is mature, and it is the current mainstream backplane solution. Glass substrate is expected to become an alternative solution with its advantages of high flatness, line width and line spacing, and good heat resistance, but due to the nature of glass being easy to break, it has not yet been widely used due to low production yield and high cost.
There is limited room for reducing PCB material costs, and the cost reduction ideas in the substrate link are focused on reducing the amount of materials used and turning to glass substrates. There are many participants in the PCB board market, and the global supply structure is fragmented. Mini LED TVs have significantly higher requirements for PCB boards than ordinary TVs, and the import ratio is still high. From a cost perspective, the price of PCB boards has basically approached the material cost, and there is limited room for cost reduction in the upstream PCB. The mainstream cost reduction ideas include: 1) Use PCB boards such as fishbone and light strips to reduce the direct use of materials. 2) The comprehensive performance and theoretical cost of glass substrates are lower than PCBs, and the PCB is turned to glass substrate solutions. 3) Further increase the domestic ratio.
