0606
Since 2013, the development of small-pitch point pitch has been from P2.5, P1.9 to P1.2; these point pitches are all produced and assembled by 1010/0808 RGB packaging components. When it comes to micro-pitch applications below P1.0, Hongqi took the lead in 2014 In 2016, the world's smallest RGB package component 0606 lamp bead was developed. This component is specially designed for micro-pitch applications. In the early days of development, many material manufacturers and customers thought it was too small and unbelievable. They believed that putting three RGB chips in such a small component size was definitely a severe test in the packaging production process! Moreover, it must be able to maintain the yield rate during mass production, while also taking into account reliability and performance.
Of course, in terms of micro-pitch, in addition to LED, there are also PCB, Driver IC, SMT, etc. to consider. Among them, the SMT patching process is the most difficult. Because the 0606 product is small in size and the solder pin size is also small, the thickness of the steel mesh and the size of the opening of the patch are very important. If these problems are not noticed, it is easy to cause the lamp to be skewed, tilted, or tilted after SMT patching. Offset, solder tin exposure affects contrast, etc. All the above problems are bound to affect the display effect! As for single lamp components, placing the RGB chip also requires precise machine tools with precise tolerance control, and the single lamp cutting process after packaging and molding is also quite a challenge, and no deviation is allowed! It has been five years since Hongqi mass-produced 0606 in 2014. The production yield and process of this lamp bead have reached a considerable level in all aspects. However, the current 0606 lamp bead is still a front-end product with fine spacing. The manufacturers that are capable of using it are not popular enough and are still concentrated in the first few first-line factories. However, we at Hongqi also have specific solutions, that is, we also developed the world's first integrated lamp in the same year (2014). Gong's "4-in-1 lamp bead" was also at the forefront at the time. However, due to exclusive supply, it could not be fully implemented until the fourth quarter of 2018. At the same time, it also developed a variety of 4-in-1 products with different dot spacings!
4 in 1
Our company calls this package Mini COB, which is a micro COB. You may think it is different from traditional COB? Traditional COB products have always been researched by teams, but the problems they face are nothing more than consistency and maintenance problems, resulting in low mass production, and our company's Mini COB was first developed by our company in 2014. The idea at that time was the 2*2 pixel concept, so it was named Mini. At that time, the point pitch we first developed was P1.25mm. It was first unveiled at the Electronics Show in Munich, Germany in 2016. At that time, a 110-inch display was exhibited with FHD resolution, which was quite different from traditional SMD components (1010/0808/0606) In addition to having 4 pixels in one package, during SMT patching, 4 pixels can be patched in one action (traditional components only patch one pixel in one action). The patching efficiency is equivalent to 4 times that of traditional components, and the cost of patching can be reduced! It also has high welding strength. The welding of traditional SMD components (1010/0808/0606) There are 4 pins, which can easily cause the lamp to fall off due to assembly collision after patching, resulting in increased number of repairs and difficulty in maintenance. The 4-in-1 Mini COB has 8 solder pins, which greatly improves the soldering strength and makes it less likely to cause abnormal lamp falling out during assembly or maintenance. The number of repairs can be greatly reduced; in addition, the use of 4-in-1 lamps can also reduce the number of PCB layers of the driver board, which can achieve the effect of dropping 2 layers, and can also reduce the cost of the driver board PCB; overall, the 4-in-1 Mini COB talks about the reduction of the entire total cost, especially in terms of post-sales service costs and maintenance costs. Because the lamp body is not easily damaged, it can greatly reduce the chance of technicians going to the site for repairs. (The overall performance can be compared in the table below)
The 4-in-1 Mini COB currently owned by Hongqi has a point pitch of P1.588/P1.5625/P1.25/P0.9375/P0.75/P0.625. The larger pitch can meet the general indoor or rental market, while the smaller pitch Mini LED can support future ultra-fine pitches. Hongqi has products corresponding to these parts, and continues to develop them, except for the 4-in-1 Mini In addition to COB, product research and development is still moving forward, and it is also focusing on flip-chip Mini LED COB, so that Hongqi will not be absent in this era of hundreds of schools of thought in the display industry.
Flip Mount Mini LED COB
With the evolution of product technology, from the above-mentioned traditional SMD component 0606 to the 4-in-1 Mini COB, I think it finally came to COB (Chip on board). Micro LED, which is now very popular in the market, although there are still some difficulties in implementation, but the next best thing is to settle for the next best thing. The term Mini LED has been widely mentioned by everyone; what is Mini LED? Some people say that a chip smaller than 8mil is a Mini LED, while others say that a Mini LED is a chip smaller than 40mil-2? In short, it is a small flip chip type chip! In the past, LEDs used so-called flip-chip and COB-type packaging in the lighting field. This has been around for many years and is considered a very mature product. However, the flip-chip Mini LED COB packaging in the display field is a little bit special, that is, in a unit area, it consists of a flip-chip RGB Mini LED with multiple pixels. In the past, COB was made with wires, but now it is all inverted for Mini LED. Installed, the precision welding bonding wires are missing, and the reliability has been further improved. To put it bluntly, the original formal wiring chip is replaced by a flip chip. Each pixel has at least 5 fewer wires, and the distance between the wiring is reduced, and the point distance between pixels can be reduced. Denser, in order to pursue micro-density spacing, major chip manufacturers are also working hard to make the flip chip size smaller. Taking the current flip chip size of first-tier chip factories, there are 5*10mil, 5*9mil, and the current minimum is 4*7mil, with the middle P&N The gap is only 70-90um. This is actually what I mentioned before. How can we do precision processing and how can we accurately control the tolerance range? Let the chip be placed stably on the COB board we designed. The chip cannot be rotated, offset, tilted, etc.; if the above situation occurs, it will cause serious display abnormalities! In addition to the process of placing the chip on the driver board, the appearance consistency after packaging is also a major test. If the appearance is uneven in color like bricks (uneven color development or uneven ink color), this will not be accepted! After that, the yield rate of manufacturing is also a challenge. If we talk about traditional SMD groups The yield rate of components (1010/0808/0606) and 4-in-1 Mini COB packaging is 99.5%, which is considered top-notch, but if this yield rate is applied to flip-chip COB, it is completely unqualified, and I think such a package must achieve more than 99.9999%! That is the concept of 1PPM, which is quite difficult. After all, flip-chip Mini LEDs are used for display. What we want to pursue is high-end applications. In addition to the requirements for poor low PPM, such as the wide color gamut and HDR required nowadays, this is also one of the technical levels to be considered at the same time. At last year’s Touch Taiwan 2018 exhibition, we also exhibited P0.75mm and P0.84mm Mini LEDs made with flip-chip Mini LEDs. Although the COB cabinet is still in the engineering stage, it still requires continuous technical improvement.
Summary
The three products discussed above actually have their own advantages. It just depends on how you design and choose; and Hongqi is in SMD We have been in the field of LED for nearly 25 years, especially in small-pitch RGB components. We have invested a lot of resources in order to provide our customers with the best products and services. In addition to the above-mentioned development projects, we also have considerable research on color, such as: Rec.709 for HD screens, DCI-P3 specifications for theaters, and UHD standard Rec.2020 (type). These standard wide color gamut specifications can be supported by Hongqi's products, allowing customers to choose the best LED for your application.
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