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Default Converting a 200W discharge lamp video projector to LED



"N_Cook" wrote in message
...
On 27/09/2013 18:35, Jeff Liebermann wrote:
On Fri, 27 Sep 2013 14:34:59 +0100, N_Cook wrote:

Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
degree, for proof of concept. (...)


I've done this with marginal sucess. The problem is focus. The
original light has all the light coming from roughly a single point.
An array of 5 LED's will distribute the light over a much larger area.
It will work well with light from the central LED using the original
reflector, but the outer LED's will be wasted and splattered all over
the room.

You don't really need the original reflector if the light source has
its own forward facing reflector. Try cramming an MR16 bulb in place
of the projector bulb and reflector. The smaller size MR16 lamps
might fit.

Mo
http://www.instructables.com/answers/Change-a-projector-lamp-to-LED-/


All the discharge lamps in video projectors , I/ve seen have an electrode
and squashed , not optically conductive glass, axial exactly in line to
where you want the light to go.
With directional 20 degree central LEDs, and lensed 4 degree ones
off-axis. will direct most of the energy directly to the half inch
aperature , without any reflectors . Reflectors just to mop up spill over
.
I can see some high power red LEDs being added to counter the blue
sub=peak


My experiments have shown that the use of a collimating reflector
specifically designed for the LED package being used, brightens the forward
beam significantly ...

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