Torches using dichroic bulbs

I've just arrived back from Maplin and have come across Dichroic bulbs and fittings and see that 6V are now available.
I would like to see some examples of dichroic torches. SLA or nicad powered?

The only dichroism that I'm familiar with is the treatment for glass that causes blue light to reflect and yellow light to go through--from my days with B&W photography.

What are these bulbs like?

Dichric is a glass coating that is used to reflect certain colors and transmit others. It can block any color or colors and is used on reflectors to let infra-red heat leak out the back and have a cooler beam. Interestingly, the colors that are reflected change with angle of incidence, so a blue filter transmits blue straight on and the reflected colors fan out 90 degrees from straight like a prism.

How is this usefull for a lamp I dare ask?

Dichroic lamps are used in halogen fittings and are normally AC powered from a transformer (12V rms). They consist of a reflector and a sealed in bulb capsule and a filter preventing IR and UV from escaping. They are available in wattages from 2W to 75W, voltages from 6V to 240V and the filters also come in vivid colours All the lamps except for the 240V ones have a bi pin connector on the rear.
The Lower voltage and wattage ones should theoretically work in a portable light source...

Dichroic coatings are thin films of metal, vapour deposited on to glass, by varying the metals and combination pretty much any colour can be obtained.Or as other people pointed out an IR transparent mirror making for a cool(er) beam.

Yup,the colour is angle dependent, on the MR16 dichros with coloured dichro front glass the colour is pretty uniform out of the front because of the narrow beam angle of the lamp.

In flood lights with dichro colour filters the angle colour change is very apparent, sometimes wiith attractive results.

Automated lighting fixtures for entertainment use dichro colour filters as they are very long lived compared to plastic coloured gels.And the narrow optical path internally keeps them one colour.

Vari-Lite were one of the first to use dichro colours in this way and the VL5 uses the angular change in colour to good effect:

http://www.vari-lite.com/Products/Rental/vl5_index.phtml

Going some miles away from original thread but anyway......

Think some cycle lights use MR16/MR11 lamps but usually use a sealed lead acid battery as the power source.

Adam

I think that I've seen scooters with this type of light used.