Why is a LED bulb able to produce more light using less lumens than its traditional counterpart? Although a LED bulb creates less lumens than a traditional bulb; is it possible to get the same or even more light to shine on my bookshelf using it? The answer is yes. How is that possible you ask??

The answer is simple and yet as an LED fixture sales person I am constantly being asked how we can replace a traditional 1,000 lumen light product with a 500 lumen LED product. People tell me it is impossible, here is why it is possible!

In a traditional bulb, light comes out of the bulb in a 360º angle. Typically, when using a bulb you are trying to illuminate a particular area such as a street or a painting in your home. In these instances you want the light to shine on your subject but not necessarily in the surrounding area. Now the light needs to be culminated to put the most amount of light possible on your painting. To do this you add a reflector to your fixture and voila you have the light where you want it. The problem is that almost half of the light is trapped inside of the fixture and you are left with only about half of the actual light output, since 30-60% of the light never finds its way out of the fixture. This is due to the fact that the 360º bulb is quite inefficient in making light usable.

A LED is built much differently than a traditional bulb. The base of a LED is called a substrate; on top of that the chip (which produces the light) is placed on a sub-mount. Around the chip lies a reflector and on top of that is the lens. Typically a LED releases light out of its lens in a 90º to 120º angle; less than half the beam angle of a traditional bulb. Secondary optics are used to modify the output beam of the LED such that the output beam of the finished lamp will efficiently meet the desired beam angle. There are two primary categories of secondary optics used; one spread the light (diverging optics). The second gather the incoming light into a collimated beam (collimating optics). The combination of the smaller initial LED beam angle and the ability to use secondary optics to refine the beam to a larger extent allows fixture designers to place more light where you want it, using less light than traditional lighting products.

The answer then is that, LEDs are simply more successful at putting light where you want it. LEDs eliminate the wasted lumens that are an unfortunate byproduct of traditional lighting.

Written by Amy Falzone of LED Light Technology.

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