COB VS SMD VS MINI 4 IN 1

In recent years, COB has swayed traditional SMD with various technical advantages, and the industry has almost reached a consensus: COB is prosperous, the industrial revolution is inevitable, and the future is the world of COB.

However, mini 4 in 1 suddenly comes up and catches the eyesight of a bunch of people who are hesitating.

The interesting point is that when the pixel pitch is getting smaller, the reliability of the traditional SMD will be reduced,SMD is reaching its physical limit. The birth of the "mini 4 in 1" makes a game between two factions in the industry, namely: the contest between the reformist and the Innovationists.

Recently, the two factions stand in their perspective and patiently give a lot of professional technical science and trend sharing. However, For many people. they are puzzled: both sides are reasonable and make sense, but we still have no ideas about who is telling the truth or what they are.

This article is to make you a clear idea about what is going on with these two techniques and how they work:

Mini 4 in 1:

You may know my Parent SMD and COB, they were originally the main and original members of the family "small-pitch display", but both my parent gradually found their career bottleneck after years development, I was born with "mission impossible" while they are getting "old".

You are not mistaken, I am the new life with both features from my parent SMD and COB, The great thing is that I am good at inheriting the excellent genes of "parents", and at the same time avoiding some negatives from "parents" and growing up. From the inside out, I am growing up and conforming to the current mainstream aesthetic(ie market demand) - a small integrated package of high-speed patches.

I am very grateful for inheriting the excellent genes with good appearance and consistency from my father (SMD). My father's mature sorting technology has been used for many years, which can make a uniform color with good consistency and effectively reduce the failure rate, in general, I can achieve good color consistency.

Speaking of this, fortunately, I did not like the mother (COB), she has an "encapsulated module" face. After all, if the module is sealed together as a unit, it will not be possible to split and separate each color for every pixel. well, you may be suggested why don't make a strictly selected process before the seal, however, it will bring much more cost, by doing this, he loses competitiveness on price.

COB:

Thank you for your continued attention to me. I am a father now, you may already know his name "mini 4 in 1"I was also very excited at first. After all, being able to pass on the excellent genes is great. However, after a several month's observation,I found that it actually inherited 99% of SMD technology genes, but only less than 1% of the technical genes from me, well, I am awkward.:(.

Everyone knows that I am reliable (high reliability, strong protection)man, though I also had some problem-display consistency and ink consistency (my wife SMD has the same problem when her pixel smaller than 1.2)It is difficult to solve the problem of ink color consistency by adding a mask), but it is getting better with more mature calibration technology, and the more matched package glue materials. It may only be 60 to 70% consistency at the beginning of last year, but now it is possible to do 80%-90%, and this year, the overall effect is no longer flawed, so Samsung and Sony have adopted COB packaging technology on the latest Micro LED display.

COB is an integrated packaged chip, and it really cannot be mixed like a single LED. Therefore, from this point of view, in terms of display consistency, COB is weaker than SMD (also can be said mini four-in-one) small pitch products. However, due to the development of correction technology, it is possible to solve the display consistency.

Mini LED: I use the same technology, materials, and craftsmanship as SMD, but I am better than my father (SMD) because the exposed area of a single lamp reduced by half and the reliability is doubled,so the maintenance frequency is also reduced by at least 50% compared to SMD. At present, there are many manufacturers involved in the upstream and downstream industry chain, it is a very mature supply chain now.

How to repair it? So easy, only need to remove the failed lamp by welding torch or other means (such as infrared), and then replace it with normal lamp bead, no need to deal with the whole module, low maintenance cost, high efficiency is really high Almost every 3 minutes, you can repair a lamp bead. If you master the "know-hows" of maintenance, you will get it in 1 minute.

But my mother (COB), if she is ill (bad point), makes people more anxious, because it may not be able to solve the problem immediately, or replace the entire module, which is too expensive. and after replacing the LED chip with the silicone rubber, restore the original color will be trouble.

COB:

The LED display industry is in its 30s, and the problem of repairing dead lights has always been a headache. This is why SMD and mini four-in-one always like to ask maintenance problems because they have always been high in failure rate, 10/200ppm (the standard of liquid crystal is less than 3ppm), have to repair, so behind them They are also equipped with a huge maintenance team.

But our COB is different. The traditional LED display panel is a manufacturing technology of 10,000 grades, so it is not surprising to repair the lamp, but the COB panel is a million-level manufacturing technology, equivalent to the concept of LCD. After production, there is no need to repair the lamp.

The low COB failure rate is recognized, and we do have a lower probability of dead lights than SMD and mini four-in-one based on bracket technology. On an actual real-time test of 365 days of the year, we have almost no need for after-sales maintenance. The full-color failure rate can reach 6ppm. The COB packaging technology of 2K system has only a few failure points, far less than Other technical routes.

I know that the industry often rumors that COB can't be repaired on-site. We can do both individual and modular maintenance methods. In some cases, the laser is used to break the dead point, and the new chip is placed and resealed. The module is directly removed by a special tool and replaced with a spare module.

Note: The maintenance cost is mainly related to the maintenance frequency, labor cost and material cost. If it is a single led maintenance method, the difference for materials and labor costs will not be huge; but if the COB needs to replace the module, the material cost is a problem. However, the failure rate of COB is lower and the frequency of maintenance will be lower.

Conclusion: In the failure rate of this game: COB wins; in the maintenance difficulty level: mini four-in-one slightly better;

Reliability and protection performance

COB:

you will be able to notice a phenomenon when you go to the LED display exhibition: some LED displays you can touch it with hand while some, you find a special reminders - don't Touch！if you touch it a little bit, or if you have some bumps in the transportation process, you may lose the light...

Why is there such a difference? This difference comes from the difference in the packaging technology route.

The less QC process a product has, the higher the reliability will be. The SMD route uses four-corner or hexagonal brackets to have reliability problems. For example, the lamp bead surface reflow soldering process needs to solve the problem of a large number of bracket pin soldering yields. The mini four-in-one bracket pin has been reduced from 16 to 8, but it still has exposed pins or open devices, and there are still risks.

The COB is encapsulated with a micro-circulation system that is well sealed. It has IP65 protection when sealing the glue. It is not afraid of high and low temperature, high humidity, high salt spray, and high corrosive environment. Commercial and even civilian grades provide effective protection during bumper installation and handling, and wet wipes, cleaning, etc. are not a problem during use.

Besides, the heat dissipation performance directly affects the life of LED products. The positive and negative of LED chips of COB are directly connected to the circuit board on the PCB. The heat conduction path is the shortest. There is no intermediate medium, and the thermal resistance is the smallest.

Mini:

I have to admit that my mother COB has an inherent advantage in preventing bumps. But fortunately, I still inherit the beneficial genes in my mother. It is not hundreds or thousands of pixels, but the integration of four basic pixel structures, the geometry is just right, which makes me stronger. After all, some things don't have to be perfect. From the perspective of reliability and protective performance, compared to my father (SMD), the colloidal adhesion is N times higher, the lead welding thrust is N times higher, So everyone, please call me Mr."Just enough".

As for heat dissipation, it is related to the driver IC. The current common cathode design can help me to reduce the temperature and energy consumption by 15%~30%, which is appropriate.

Note: In theory, after SMT reflow, the mini four-in-one reliability is higher than SMD, four led to share the common negative and positive pole.

Conclusion: In terms of reliability, protection performance, and heat dissipation performance: COB wins

Cooperation of industry chain

Mini:

My birth was made by the help of market demand pain points because the market needs a player with strong comprehensive strength suitable for the present, rather than a single champion.

many people also regard me as a small expert who "takes the essence, goes to the dregs, and exalts the high intelligence" - because I have retained a very important trait. Because of this trait, the packaging factory and the screen factory have been gearing up and courageous to try - that is, compatible with the original packaging and display screen equipment, but also reduce the terminal cost. The cost of PCB is positively related to the number of layers. I can reduce it from 8 layers to 6 layers of PC. It also makes the placement efficiency nearly 4 times higher than that of traditional SMD, which greatly reduces the cost of SMT and shortens the delivery time as well. That is why players in the industry chain are willing to work and cooperate perfectly.

However, if the COB the thing is different:

The original SMD industry chain is: upstream (LED chip) + midstream (package) + downstream (display plant)

to COB, the industrial chain form becomes: upstream (LED chip) + Downstream (package panel factory). In other words, the original SMD factory needs to be upgraded devices, and there is nothing to do with the screen factory with the process of "SMT".

This means that the midstream and downstream links are directly reduced to “downstream”. So who is going to play the role of “downstream”? Packaging factory? Screen factory? Or some New players?

So there are many challenges: What they are going to do with the original millions of dollar types of equipment? Who will steal my market share? Without the SMT process, barriers to entry get lower, and more screen factories will emerge to make the competition even more fierce? all kinds of worries and doubts, makes those players stunned and hesitate.

Of course, there must be real warriors, dare to face up to the dripping blood, and more to see the opportunity in the crisis instead of threats. After all, in addition to the patch technology, the system application of the LED display and the optimization of the structural design of the whole machine are also very Important core competencies.

However, they are all adults. Compared with humility, of course, the benefits are more impressive. This is very human. For the vast majority of entrepreneurs who are responsible for investors, shareholders and employees, of course, the lower the risk, the better. This is a bit embarrassing. I am all-inclusive and intimate.

I am grateful to my mother (COB) for imparting the ability of “Reliable and Anti-Bumping Ability” to me, which makes me make up for the shortcomings of my father (SMD) and the “black” of my mother (COB). The problem of poor consistency is that the image of "good visual sense, easy maintenance, high reliability, strong anti-smashing, and high assembly efficiency" can be realized.

COB:

The revolution of the industrial chain below P1.0 is an inevitable trend, but all enterprises that have a precautionary spirit and a sense of urgency should be clear that this is cruel and realistic, but no one can stop it. It’s just that this time node is coming earlier or later. Of course, I also know that it is very comfortable to work hard, and the effort is not necessarily successful, but it will be beaten behind.

From all perspectives currently available, COB is the best choice for high-end segmented LED display applications and on the road to the Micro LED era. I don't know, those who seem to be themselves a mini four-in-one camp, have privately spent a lot of money to study me. So, when one day knows the truth, don't be surprised: say good to play 4 in1 together, but you secretly do COB with me.

Note: With the mini four-in-one, the industry chain players can continue to turn comfortably at the lowest input cost; when they invest in COB, they have the opportunity to rewrite the industry chain brand pattern and market share, but they will become martyrs. Still a pioneer, it depends on their creation.

Conclusion: In the industry chain cooperation and rapid industrialization ability: mini four-in-one wins.

Summarize the above conclusions:

> In the display effect: mini four-in-one temporarily wins;

> In the industry chain cooperation, rapid industrialization ability: mini four-in-one wins;

> In the difficulty of maintenance: mini four-in-one slightly better;

> on maintenance costs, tie a tie for now ;

> COB wins in failure rate;

> COB wins in heat dissipation performance;

The new applications made possible with a new generation direct view LED are not just visually exciting, they bring new business opportunities. But even as direct-view LED is taking the AV markets by storm, how do you separate the market-leading direct view LED suppliers from the many late-comers to the market, if your goal is choosing LED based on quality, service, and track record? in NEXT ARTICLE I will share with you with questions you should ask as you make that choice, and help you understand best practices that are emerging in the industry for direct-view LED selection, commissioning, implementation, and maintenance and service in the field. if you like this article, please subscribe.