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Issue #2
COB - Combined On Board  Light Emitting Diodes Flashlights Review
COB - Combined On Board  Light Emitting Diodes Flashlights Review
Welcome to the 1776.CLUB Weekly Blog.  This Blog is a multi-topic look at different technologies as well as the unusual, the odd, and the bazar. I look forward to entertaining and informing.  Please tell others where you found me.
COB LED's
COB
COB (Chips on Board) , is a new technology of LED packaging for the ever popular LED light engine. These multi LED chips are packaged together as one lighting module.  Once you have seen just how bright these LED's are you won't want to go back to your old flashlight!

The COB LEDs
Relatively new to the LED market, chip on board (COB) LEDs are super bright and run cool giving them long life.  I first discovered these new LED's at a discount store and tried them out. A 400 Lumen output with 3 AA batteries would last almost 3 hours.

COB LED's offer many advantages over the standard options. COB LEDs are basically multiple LED chips (typically nine or more in a row) bonded directly to a substrate by the manufacturer to form a single module.

Since the individual LEDs used in a COB are chips and not traditionally packaged, the chips can be mounted such that they take up less space and the highest potential of the LED chips can be obtained. When the COB LED package is energized, it appears more like a lighting panel than multiple individual lights, as would be the case when using several SMD LEDs mounted closely together.
Advantages of COB LEDs
Here are some of the advantages of the COB light.  Being they are multi-chip packaged, the light emitting area of a COB LED can contain many times more light sources in the same area that standard LEDs could occupy resulting in a greatly increased lumen output per square inch.

I have learned that the COB LEDs use a single circuit with just two contacts to energize the multiple diode chips in which it houses. This results in fewer components required per LED chip for proper operation. Furthermore, the reduced components, along with the elimination of the traditional LED chip structure packaging, can reduce the heat generated from each LED chip.

The ceramic/aluminum substrate of COB LEDs also acts as a higher efficiency heat transfer medium when coupled to an external heatsink, further lowering the overall operating temperature of the assembly.

I learned the hard way, when mounting a COB to a heatsink, care must be taken to choose a heatsink capable of dissipating the heat generated to enable a COB to be used to their full potential. In the long run, the proper heat dissipation increases efficiency and lowers failure rates.

Another aspect of COB LEDs that reduces failure rates is the fact that spot soldering of the individual LED chips is not necessary as each chip is directly mounted onto the substrate. The smaller amount of welding points results in lowering the rate of failure.  This is not true of the standard LED's like you see that have a half dozen or more failing LED's after a short period of time.

Light loss is decreased significantly and viewing angle is increased both due to the fact that lenses and other traditional LED packaging parts are no longer in place when using COB LEDs.  In other words, the LED focuses the light in one area while the COB spreads it out in a wide angle.
The disadvantage of COB LEDs
COB LEDs do have one disadvantage in that they currently are available in a limited variety of colors (blue, green, pink, red, cool white, neutral white, and warm white).

There are Many Applications for COB LED lighting
The application possibilities for COB LEDs encompass a wide range. While these devices could be used for higher output general lighting, the primary use for COB LEDs would be as solid-state lighting (SSL) replacements for metal-halide lamps in applications such as high-bay lighting, street lights, and high-output track lights and downlights.

LED(light emitting diode) is new technology with advantage of saving energy and very long lifespan. But all LED lightsource can not be faultless especially SMD, HP, flux LED etc.

Compare to traditional lighting such as fluorescent lamp, as it is super bright in a small size, it cause uncomfortable glare. In case of no diffused optical lens used, such LEDs usually cause glare and zebra strips . But when optical lens or cover used, it will cause light loss when LED beam pass through this lens or cover.


Oh So Bright:
COB LED is multi chips packaged, it can 10 times more increase lighting area, so it avoid uncomfortable glare by the maximum extent.
Lightspot use small size of chips to make COB LED package.

By now, for small size chip LED manufacturers intensity can reach 249lm/watt @ 20mA. But big size LED chip can only reach 161lm/watt @350mA. The light efficacy decrease when chip size is bigger. Also when LED driver increase current to LED, the light efficacy per watt is even lower.

The COB with small size chips will be a trend of LED light source package.

Lightspot holds the patent for invention for COB LED and lamp.

HLO LED's - (High Lumen Output)
This recent LED technology is largely responsible for the possibility of, adoption of LED as a viable alternative to incandescent and mercury-based lighting. SMD chips allowed manufacturers to automate production, improve quality control and offer a product that features; better heat dispersion, high lumen output (high lumen flux ) and longer overall life (low optical decay) than its predecessor the DIP LED .

The SMD chip itself is created from layers of man-made nano sapphire and gallium crystal layers that are bonded to a ceramic base that can be easily mounted in various package LEDs.

Far from being outdated, SMD LED continues to improve in its lumens per watt output, these small, maintenance-free long-lasting solid-state light sources will be around for many years to come.

COB (Chip on board) LED technology, differs from traditional LED in that instead of individual SMDs soldered to a circuit board and then mounted to a heat sink; the Wafers or “Wafern” are cut into some hundred small chips, with a thickness of only approx. 250 µm. These tiny small and hardly visible pieces of semiconductor crystal are bonded directly to the aluminum substrate (with a proprietary bonding procedure) allowing for optimum heat dissipation, and solderless fabrication.

YELLOW PHOSPHOR:
The yellow discs are simply a phosphor coating, enabling complete control of color temperatures.This type of LED technology makes chip densities up to 70 chips per square centimeter possible, and promises to offer much more flexibility over other LED technologies.

CREE and a few others make integrated chips, but are currently prohibitively expensive.  MCOB is also found in LED bulbs and LED tubes, however compared to SMD surface mounted diode technology, MCOB technology is still in its infancy.

Before COB technology, LED spot lights and flood lights were historically considered “non-standard lamps” because they required multiple LED sources to produce a high lumen output.

Since the advent of COB chips in the LED arena, a large lumen count can be produced from a single source using a COB chip. This was never possible before COB, but has been a revolution for people who want to lower their energy bill but also need a standard lamp. Besides spot lights and floodlights, COB chips have been put into all kinds of bulbs and used for a number of other applications as well. In fact, COB technology is used for any small device with a flash such as a Smartphone or camera. The principle is that COB chips produces a large amount of lumens for very little energy, which is very important for any device that runs on a battery.

I purchased an COB 400 lumen pen light called a Big Larry. I runs on 3 AA batteries.  At 400 lumen it can run 4.5 hours.  On low, at 160 lumen, it can run 12 hours.  Prices range from $8 to $19 depending on where you get one.

MCOB
Since the creation of COB chips, a variation has come along called MCOB or “Multiple Chip On Board”. MCOB devices are very similar to COB chips in their application and are more or less just multiple COB chips together in series. MCOB devices differ from COB because they are better for low wattage situations.

They also do not fulfill the standard lamp requirement for spot light and floodlights. While MCOB devices do not meet these requirements to become a standard lamp, they produce a lot of light and are great for low wattage situations like A19 bulbs. In fact, A19 bulbs are currently the most common use of MCOB technology. If you buy an LED A19 bulb in the near future, it will likely be an MCOB bulb.

In my search for the brightest COB that could be hand held, I discovered the MCOB which is a very new technology at this point that not many manufacturers are producing, but it will likely catch on for much more than just A19 bulbs.

There are many applications for a high lumen count that MCOB can fulfill, and likely innovators will use the technology to create new products that the market has never seen before. The world of LED lighting is exciting when we see that it is changing and evolving right before our eyes. Soon we may have yet another technology that is a contender in the LED market!

The Future of COB and MCOB:
Already we are seeing minimal lumen degradation and excellent 80+ Colour Rendering Index (CRI) to optimize pupil lumens and visibility in all end user conditions.

These newer MCOB's feature Unparalleled Operational Safety while giving off Negligible electronic pollution. These do not affect electrical and mechanical systems, equipment, sensors and smoke detectors. No RF!  They also provide the Lowest possible THD (total harmonic distortion), EMC (Electro magnetic compatibility) and EMI (Electro magnetic interference) to date.

MCOB technology is more than just one cup of integrated modular production, MCOB the modular production must be the mainstream of the future.  Why? It is because the modular design can make a relatively large area light up, and with better heat dissipation, the second is can effectively reduce costs.



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