Reporter: Li Wenlu
Invited guest: Zhang Renhong, technical director of RGB device R&D at Hongqi Technology
1. Now more and more companies are keen on small-pitch LED displays. As a device manufacturer, your company, how do you view the small-pitch LED display market? Can you explain from the market, profit and business aspects why companies are keen on small-pitch LED displays?
Zhang Renhong, technical director of RGB device R&D at Hongqi Technology:
Enterprises and the market are also seeking innovation and change, and it is human nature to pursue beautiful things. In the case of the display market, small spacing can greatly improve the resolution of the screen and even move towards the level of LED TV 4K. Small spacing products have opened up another blue ocean for the murderous Red Sea market of the display market, allowing the market to pursue higher-level and more detailed displays without having to engage in vicious price competition with rivals in the original Red Sea market. This is also a vicious cycle of bad money driving out good money. What the industry does not like to see is that Hongqi Technology has been highly praised by the industry since it launched 1010 LED matte black lights for small spacing in 2013. This has given industry friends who were previously unable to enter the small spacing market another sales tool. It has also opened another door for the industry to enter the small spacing or even micro-pitch market. This can also explain why packaging companies, display manufacturing and even application companies are keen on promoting the small spacing display market.
2. The small-pitch display screen has been produced, but in the face of different customers, the functions required by customers are different. From the perspective of a packaging company, how does your company handle the entire solution?
Zhang Renhong, technical director of RGB device R&D at Hongqi Technology:
Hongqi has designed two representative products for customers with different needs and applications: 1010 & 0606 LED. These two models can meet the display screen requirements of customers from Pitch 2.0~0.8mm. The "ultra-fine fine pitch" currently expected to be mass-produced is 0404 LED, which can assist customers in designing to Pitch 0.6mm (Real LED TV) to achieve true perfection. Real LED TV instead of LED Backlight TV. At the same time, in order to work with our customers to design LED TVs for home use, Hongqi Technology is currently the only packaging factory that manufactures and manufactures in Taiwan and can realize a single specification grade and ship in a single batch at the same time. In order to improve the consistency of the lamp body, each batch of lights is mixed evenly before shipment by the "ultra-high-speed lamp mixing machine" co-designed by Hongqi and Germany before being shipped to our customers.
3. The key cost of small-pitch LED displays is concentrated on the lamp beads. How do you think the production cost of small-pitch LED displays can be reduced from the packaging process? What is the biggest technical level problem currently faced?
Zhang Renhong, technical director of RGB device R&D at Hongqi Technology:
With the advancement of packaging technology, lamp beads have evolved from 3528 in the past to 2020, 1515, and even 1010 lamp beads, which has now caused a trend of small spacing; similarly, due to the advancement of packaging technology, the design capabilities of back-end system modules have also been greatly improved. In fact, not only lamp bead packaging and display manufacturers, but also upstream chip factories have also responded to this trend and made smaller and brighter chips. The upstream, mid-stream and downstream industrial chains are more closely integrated; the smaller the package, the smaller the dot pitch, and the smaller the dot pitch of the display screen, the more lamp beads are used, and the cost is more expensive. How can it compete with the current LCD TV? Recently, the very popular 4K2K LCD TV has come out one after another. I believe it is another stimulus for the display screen, stimulating the continuous growth of the entire industry! The production of lamp beads has evolved from the past TOP glue-injection type to the current PCB carrier board pressing model. The production process is very different from that of the glue-injection type. In terms of brackets, the bowl and cup design of the original glue-injection type must be abandoned and directly molded in a similar die-casting method. In other words, this type of lamp bead, The appearance is determined after the molding; the design of the PCB substrate and mold becomes the key. Back to the topic: How to reduce the cost of small-pitch LED lamp bead production from the packaging process? The biggest technical level problem currently faced? Regarding this part, I have several opinions:
The layout rate of PCB increases the layout rate of the entire PCB. The higher the layout rate, the higher the utilization rate of the die sealant. This means that all raw materials and materials can achieve the highest utilization rate, and even the overall production efficiency is improved. Let me give you an example: a 1010 lamp bead, on a piece of P 1010 lamp beads of 2016ea can be arranged on the CB. During molding, 4pcs can be placed at one time, so that one molding can produce 8046ea lamp beads (2016x4=8046). However, if a PCB can be arranged with 2500ea, it can be placed during molding. 8pcs, so that one stamping can produce 20,000ea, which is nearly 2.5 times that of the original design. However, the amount of stamping glue input is the same! And the overall production efficiency has also increased by nearly 2.5 times. When the quantity is small, the difference may not be seen, but if it is like now When the quantity of a screen is often 10kk, you can clearly find the difference in cost! What we are facing now is indeed the so-called layout rate problem. PCB can extend the layout rate, but the size of the molding machine is limited, because it is related to the design of the mold. Whether it can accommodate P with a large layout rate CB: But think about it in reverse. If the layout rate is high, if an abnormality occurs in the stamper, the loss will be relatively high, that is, the yield rate. Therefore, we must find the best flat point in this part, and the layout rate that is conducive to production yield control will be an important issue that packaging manufacturers need to consider.
Packaging quantity in rolls In the past era of large particles, that is, lamp beads not used for indoor screens, when they were packaged in rolls, they almost always used 7-inch reels, and their packaging quantities were less than 4Kea/Reel. I think that for the current hot-selling lamp beads 1010 for indoor screens, this thinking should be broken. Why don't we use larger reels so that the roll quantity can be >4kea? In the same way, this is also an increase Increase the utilization rate of the reel and improve the production efficiency. Even when the client is patching, which one has higher production efficiency, 4kea to replace the reel or 10kea to replace the reel? The cost of lamp beads is reduced, and the cost of patching is also reduced! Moreover, I believe that in this era of environmental protection, after patching, the reel should be recycled. After all, patching can not damage the reel. Of course, this reel can be recycled to the packaging factory for reuse.
Support from the upstream chip supply chainè In fact, the key to lamp beads lies in the chip. The chip is the heart of the lamp bead. How to have a strong heart? While everyone is moving into small spacing, upstream chip factories also face many challenges. The packaging factory makes the lamp beads smaller and smaller. The key also comes from the chip factory's ability to make the chip smaller and smaller! The smaller the chip, the better the overall quality. In terms of plate arrangement rate, the light efficiency is not much lost compared to the original one. The current demand for indoor screens is about 1000~1200nits, which should be sufficient. However, the overall yield rate is still a critical issue. In addition to optical rotation, electrical issues such as IR/VR must also be taken into consideration. Even the yield rate of chip cutting is also a bottleneck. In the same way, chip manufacturers will definitely make breakthroughs and improvements.
The above shows that while pursuing small spacing, we must take into account the cost concept and the current bottlenecks we are encountering. As long as we reach a balance in more aspects, we can find the sweet spot with the highest CP value, and this sweet spot must be worked together by upstream, midstream and downstream to create more competitive products.
4. The technical process and principles of LED lamp bead products determine that the display screen has natural high-brightness characteristics. If we want to achieve the goal of indoor application of small-pitch LED displays, we must not only achieve small spacing, but also solve the problem of high brightness and low gray. The packaging process is also very important. How do you think the packaging technology should be optimized for small-pitch LED displays?
Zhang Renhong, technical director of RGB device R&D at Hongqi Technology:
In the past, what everyone pursued for outdoor screens was brightness, brightness, and even brighter. After all, the environment must withstand sunlight, which dilutes the brightness. Therefore, everyone pursued ultra-high brightness when using outdoor screens. On the contrary, indoor screens are closer to "people". If you simply think that outdoor screens can be used indoors, the impact will be great. Because the viewing distance becomes closer, high-brightness outdoor screens can cause considerable damage to the eyes, ranging from eye soreness to tears and eye lesions. Outdoor screens generally have a larger spacing and are not suitable for close viewing. As for indoor screens, because they are closest to "people", they must meet the acceptance of human eyes. For home TVs or DLPs, their brightness is about 400nits, which is more suitable for close viewing. I even think it can be reduced to 300Nits. However, this will test the performance of the overall display screen. There are advantages and disadvantages; currently, many manufacturers set the specifications of indoor display screens at around 1200~1600nits. In fact, such specifications can be lowered, and each manufacturer hopes that the display screen can enter the home in the future, and one after another launches the so-called real LED TV. As a packaging factory, we make lamps. We who are LED lamps are also looking forward to it, but the first thing to solve is the problem of low brightness and low gray! This problem is not only the lamp beads, but also the driver IC and controller, etc., which must be improved. Perhaps at 1200Nits, the overall color consistency is uniform and can reach high gray, but if the brightness is directly reduced to 300nits, various problems may arise! Common color unevenness/low gray and reddish...etc. Regarding this part, what Hongqi Technology can solve in lamp beads is to make full use of the resources within the group. Before the chips are purchased, they are first sent to the world's largest chip inspection factory "Jiuyuan Electronics". The chips purchased from the chip supplier are then screened to select standard chips with better consistency before entering the package. After packaging, they are tested with low current. The flow is sorted into grades. The same grade is used on the same display screen in order to achieve uniform color whether at low brightness or high brightness. Why mention the so-called "low current"? When the lamp beads drop sharply from 1200nits to 300nits, the driving current must drop to a very low level. While the current decreases, the overall light efficiency of the lamp beads will naturally decrease. According to the characteristics of LED, there is a considerable difference in the changes in brightness and wavelength between low current and high current. Therefore, I believe that in order to achieve "low brightness and high gray", the lamp beads must first maintain color consistency when driven by low current!
I believe that in the future, when LED TV enters the home, consumers will definitely view this so-called LED TV based on TV standards. With the current technology, there are still many breakthroughs that need to be made, and we also understand that "low brightness and high gray" will definitely be the first level. After reaching this part, the requirements of consumers and users will be met, and the overall competitiveness will naturally increase.
5. Currently, a small number of manufacturers are actively promoting small-pitch LED displays to the home TV industry. What do you think of this attempt? As a packaging company, what do you think of the development prospects of the entire small-pitch LED display industry?
Zhang Renhong, technical director of RGB device R&D at Hongqi Technology:
In July 2011, Hongqi Technology participated in a seminar held in Shenzhen for the first time. We exhibited the P3.0mm 2020 module and the P2.5mm COB display, which gave us our first taste of the attractive taste of small spacing. In September 2012, Hongqi Technology once again exhibited its P1.6mm COB display at the Munich Electronics Show in Germany, officially announcing Hongqi's determination to enter the field of small pitch and even micro-pitch.
I am personally optimistic about the prospects of the small-pitch industry. After all, for the application of small-pitch, the technology of each manufacturer has improved, and it can even be below P1.0mm; this also urges packaging factories and chip factories to develop smaller-sized lamp beads. For this part, Hongqi Technology has a specific solution. In addition to the current trend of 1010 lamp beads, it has also developed a 0606 size, which can be used in micro-pitch spacing below P1.0mm, in order to achieve a level similar to LCD. It also inherits the tradition of 1010, with both an all-black lamp body and a matte finish, to create a real lamp bead that can be used for LED TVs. Since Sony took the lead in launching an 84-inch 4k2k TV in 2012, it has declared that the entire nation will enter the era of UHD (Ultra HD). Until now, nearly one out of every five TVs is 4k, which is about to become popular. Even some so-called wealthy LCD TVs have a size of more than 100 inches, and they are also curved. On the other hand, can LED displays do the same? The answer is yes.
Using seamless splicing technology, micro-pitch displays can be infinitely extended in size, and can even be varied in shape. Here is a simple example: If large-size displays become popular in the future, everyone will want to install a display at home or in a conference room in a company. However, if it exceeds a certain size (such as more than 150 inches), installation must be difficult, because some are not even high enough for the door. , how to install the display? But if it is a seamlessly spliced LED display, the maximum function of on-site installation can be exerted. Like building blocks, the installation is completed on site piece by piece. With this simple and easy-to-understand example, I believe everyone can clearly understand the advantages of LED displays during assembly; similarly, the overall NTSC color gamut is also relatively wide, which greatly improves acceptance.
However, in addition to components, Hongqi Technology also continues to research and develop displays in the form of COB packages. After all, it will be difficult to mount the panels when working with micro-fine pitches in the future. Therefore, we have also continued to conduct research on COB Displays and have made breakthroughs. We have also improved the past shortcomings one by one. At present, we can achieve all-black surfaces of the unit boards and all-matte surfaces, providing customers with another solution.
6. How is your company’s current business development in small-pitch LED displays? How will the future be laid out?
Zhang Renhong, technical director of RGB device R&D at Hongqi Technology:
Hongqi currently maintains friendly partnerships with various domestic manufacturers. The company also regards the small-pitch LED market as the company's annual focus on the development and development project of the "Steering Wheel Plan" , the company is also currently actively cooperating with the group equipment company "Weikong & Jiuyuan Technology" to strongly expand equipment production capacity. The first phase target is initially based on 300KK/M, and the second phase target is currently being expanded in the form of OEM & ODM in conjunction with Hongqi's European and American customers.
ANNA