Material that reflects light, but not heat 1

[NonlinearMind]

I have a design problem that I'm trying to resolve and I was wondering if someone could help me:
I need to reflect light from a lamp source to a single direction by means of a reflector. The only problem is that I have to maintain the lamp temperature at a specific temperature. This creates a physical contridiction because the reflector also reflects the radiant heat, and raises the temperature of the lamp.
The solution to this problem will require a material that reflects light, but also absorves heat. Does anyone has any information on such material?

 

[TEV]

I think what you want is something that reflects in the visible wavelength spectrum, but absorbs (or is transparent to) the longer wavelength infrared spectrum. These probably exist, but I am not sure what. Suggest you post this in the optical systems forum.

 

[ornerynorsk]

In photography, and other fields as well, filters are used to isolate or exclude certain wavelengths of light. I would think that much of your radiant energy could be excluded in this same way. You may need to air or liquid cool your lamp housing to maintain your desired element temperature. Also, have you spoken with any high-end lighting manufacturers? I know that there are bulb oem's that target specific bandwidths of light by varying the element material, bulb material, and insulating gas within the bulb.

 

[cev]

You need a "Cold Mirror". The most common type, which may suffice for your application, is a faceted-parabola overhead projector reflector. The reflector is made from plastic with an interference-filter coating, and can be purchased with a plug that fits standard bi-pin tungsten lamp holders. I'm not sure, but you might even find them at Ace Hardware. Here is the first link I came up with showing an example (from 3M):

http://products3.3m.com/catalog/us/...ystems_3_0/command_AbcPageHandler/output_html

Many optical suppliers sell high-end or specialty cold mirrors. Edmund scientific has flat ones for relatively cheap. As ornerynorsk said, most precision, non-flat cold mirrors are manufactured for OEMs (medical equipment is a big application - I bet your teeth don't get hot under that lamp at the dentist!)

 

[cev]

I noticed that my link was not working well. Here's a better one:

http://www.3m.com/meetings/buy/3m_lamps.jhtml

 

[mikemoore]

Call George Panagatacos at Teledyne Lighting and Display products at 310-577-3820. Tell him Mike Moore gave you his number.