What is the COB-LED, their characteristics and the main differences from conventional LEDs

Technology Chip On Board It was used in the lighting industry. This technology, in which the chip is mounted directly on the board, is already used for a long time in the production of standardized electronic circuit boards and has proved to be very reliable with a maximum compactness.

Adaptation of this technology for the production of LED lighting has allowed to give new impetus and so rapidly evolving industry. Let's look at this article closer technology.

What is the core technology

Repeated attempts to increase the light output from the high-power LEDs SMD type while obtaining scattered light led to the birth of the idea of ​​placing a large number of crystals on the circuit board in a single housing.

Researchers have rejected the idea of ​​further increasing the power of a single crystal, and moved on to experiments to reduce the LED chips in a single package.

In the course of these experiments, and get technology COBWherein meant installing a large number of small chips, these should include a series-parallel on a single substrate.

In this case, the printed circuit board has a metallic base (Metal Core Printed Circuit Board, MCPCB) and is made of three layers: a metallic base dielectric layer and the conductive layer.

Here, the first metal layer is made of metals with high thermal conductivity, which means that MCPCB It plays a role not only the motherboard, but also the role of the radiator.

Thus on a given matrix LEDs are fixed with an adhesive, and after that are joined with each other and covered with the phosphor layer.

Thus created COB matrix emits diffuse light uniformly without overheating exposed and requires additional complex optical devices.

Thanks to this technology, you can create a matrix of arbitrary shape with a small cost that was previously difficult to achieve.

A few words about the technology complexity

Creature COB Matrix starts from preparing the substrate to which is applied a thin layer of adhesive. Moreover, the requirements for the thickness of this layer is extremely high. It should provide certain contact LED Crystals micro sizes and still provide uniform heat dissipation.

Such a perfect balance has been achieved only when the method was used magnetron sputtering. Such a spray has created thermal contact required quality, and this technology was called MCOB (Multi-Chip-on-Board).

Next, the prepared substrate with the sprayed layer and the chips are mounted using a plasma cleaning, the surface is purified by microscopic debris.

Then the electrical connection of LEDs, and is already in the final stage is applied to the phosphor layer, which after hardening in addition to its direct function, also protects parts of the board vernal impact.

distinguishing features

Like any other product COB matrix have their advantages and disadvantages.

So the undoubted advantages include the following:

The form of the matrix. Produce LED matrix COB It can be absolutely any size and necessary functional holes. That is, this matrix can be tailored to absolutely any light fixture housing. And as you can produce a duplicate of the old lighting elements and simply replace them.

COB matrix emits uniform light output, thereby subjects lit like light, have clear light - shadow border. Which can not be observed by conventional light bulbs with LED light-emitting diodes arranged separately.

These matrices have a relatively high light output options, for example, some matrices have parameters 166 lm / W.

Perhaps the only drawback of such matrices is their complete unsuitability for repair. So if you went down at least one of the chips, it is necessary to replace the entire matrix.

conclusion

While lighting products, which are based used COB matrix, still not widespread, but it is about the same pattern was observed with conventional LEDs. Further improvements in technology will inevitably lead to reduce the cost of production, which means that a cheaper product will find its customers and will appreciate all the advantages of the new technology.

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