With the evolution of product technology, from the traditional SMD component 0606 mentioned above to the 4 in 1 of Mini COB, I think we ended up with the Chip on Board, the Micro LED that is now widely popular in the market. Although it is still a little difficult to realize, Mini LED is widely mentioned. What is a Mini LED? Some say that a chip less than 8MIL is a Mini LED, while others say that a Mini LED is a chip less than 40mil-2. In short, Flip a small chip like the Flip chip. In the past, LED in the lighting field is also commonly used in the so-called flip chip and adopt COB type packaging, which has been in practice for some years, and is also a very mature product. But flip the Mini LED COB packages in the field of display screen is a bit more special, which is in a unit area, with multiple pixels of RGB LED Mini flip chip, ever do COB is done with the lineup, now on the Mini LED to flip the, all of them, and less precision welding bonding line, on the reliability and further, said colloquialism, flip chip is replaced the original dress lineup chips, each pixel less for at least 5 lines, and less, the distance between pixels and the pixels distance can do much more dense, In pursuit of micro close spacing, each big chip factory will also be the flip chip size into a little hard to do, now in a line for chip factory of flip chip size, there are 5 * 10, 5 * 9 mil mil, the minimum to 4 * 7 mil, of which the P&N Gap is only 70-90 um, this is actually I mentioned earlier, how can do precision machining and how to The chip can be placed on the COB plate we designed stably, and the chip cannot be rotated, shifted, tilted, etc.; If the above situation will cause the serious display abnormality! In addition to the process of putting the chip on the drive plate, its encapsulated appearance is also a major test. The appearance of brick-like color balance (color or ink balance) will not be accepted! Then there is the challenge of manufacturing yield. 99.5% yield on traditional SMD components (1010/0808/0606) and 4 and 1 Mini COB packages is considered to be top of the line, but applying this yield to an inverted COB is totally unacceptable, and I think such a package must be 99.9999% or more! This is the concept of 1PPM, which is quite difficult. After all, the inverted Mini LED will be used for display. What we want to pursue is high-end applications, in addition to the poor requirements of low PPM, such as the current requirements of wide gamut and HDR. This is also one of the technical levels to be considered, and in Touch Taiwan 2018 last year, we also showed the P0.75mm and P0.84mm Mini LED COB case made with inverted Mini LED. Although it is still in the engineering stage, we still need to make continuous improvement in technology.