Where do you get a replacement UV Filter for a desk lamp?

Question

The plastic UV filter on my desk lamp broke in half. Does anyone know where I can buy a replacement for it because you're not supposed to use the lamp without the filter or else it will emit UV rays. Plus...I don't want to buy a whole new lamp because the lamp still works fine.

Thanks.

http://www.flickr.com/photos/soopahviv/22547159/

Here is a picture of a lamp like the one I have that I found. It's a halogen bulb. That plastic UV filter broke.

Answer 1

I'm not sure what type bulb you are talking about. I don't know of any that require a seperate filter. The bulbs/ tubes are coated for UV in all the kind I know. More info please and I will try to help.

Answer 2

Yes, light bulbs do give ultraviolet rays. Even incandescent lights give off UV, except it is nothing compared to the amount of IR and visible in such a case. Fluorescent lights actually work because the physical mechanism of light production produces dominantly UV rays. A coating on the tubes of the bulbs contains phosphors. Phosphors receive the incoming UV from the inside and step-it-down in frequency to re-emit as visible light on the outside. You cannot see UV. When you look at a "black light", you see some violet light, but it is just the edge of the light's emission spectrum. Because we can only see with visible light, we have no purpose for UV rays. All that a UV ray will do is give us skin damage over long exposure. Therefore we desire to filter out the UV and pass the visible light. You might think that it would be of interest to place an infrared reject, visible pass filter on the surface of an incandescent bulb. Why do we do this? Well, the end result of filtering the IR just results in the filtering material absorbing the IR and becoming hot, thus emitting its own IR. There is no way to "step-up" IR to visible light, because of the quantum nature of light.