A Lesson In Phosphors And Some Cool Pictures

Remember lamp = light bulb

Take a look at an incandescent lamp or a normal light bulb. You will see the tungsten filament is producing the light (and heat). Now think about a fluorescent lamp. A fluorescent’s light is actually produced from the white coating on the inside. That material is phosphor. Phosphors emit visible light when hit by UV light. The UV light is created from a VERY small amount of mercury that is contained in the lamp. I won’t go into too many details, but when the mercury is charged it emits UV rays.  Fluorescent lights are extremely energy efficient as well as last a lot longer than their incandescent cousins.

There are two main types of phosphors. The first, tri-phosphors, are made out of rare earths on the periodic table and halo phosphors. The tri-phosphors come in green, blue and red colors. The second type, Halo, gives off different shades of white (daylight, sunlight etc etc).

If you mix the tri-phosphors together in the right amounts, you get white light! Think about how your tv works – the colored dots make all of the colors on your tv… it’s all about the correct ratio. All phosphors are white powders, but glow their color when hit by UV light. So you could make pure red, blue, or green lamps!

So part of my job at Nela is testing different companies’ phosphors to see if they compare with the standard that we currently use. I do this in one of the phosphor plants, which is located close to Nela Park.  In order to test them I actually make mixtures/suspensions of phosphor and pour that into glass bulbs. The bulbs are then made into lamps and we perform tests on them. Doing this allows us to see if the new company’s phosphor could be used as a replacement. Even a small price difference can save the company a lot of money!

And now for the cool pictures I promised. Here are three bags of phosphor – all of them look identical until I shine a UV light on them:

You can click and make them bigger.


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About nikomse
Will be entering my third year at Ohio State majoring in MSE. Currently I am co-oping at GE in Cleveland until December.

One Response to A Lesson In Phosphors And Some Cool Pictures

  1. Nice images! I’d be interested to see the benches and floors in your lab with the normal lights off under UV–rainbow colored?

    Dave

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