On 1/10/2013 1:49 PM, gregz wrote:
Trevor Wilson wrote:
On 29/09/2013 5:50 PM, N_Cook wrote:
On 28/09/2013 22:08, Trevor Wilson wrote:
On 27/09/2013 11:34 PM, N_Cook wrote:
**What a waste of time and effort. The best LEDs are approximately
similar efficiency to that of halide lamps. As others have stated, the
big problem will be that you are substituting a compact light source
with a rather diffuse one. The optics are not designed for such use.
But the lamps used in video projectors are ,in effect, not compact. The
direct light path from the reasonably compact source is blocked by an
electrode and non optical structural glass lump, relying on the mirror
surface of the light tunnel / light pipe to average out/balance-up the
light coming in at all sorts of angles, off the parabaloid reflector
**NO. By the time you try to shove 200 Watts of LEDs into the enclosure
(including apprpriate heat sinking) You're not going to be able to focus
the whole thing properly. It's a daft idea, unless you are prepared to
use MUCH less LED power (say 15 Watts) and a consequent huge drop in Lumens.
BTW: The light from a parabolic reflector does not come off at all sorts of angles.
One of my projects was making a light source with multiple colored 5 watt
LEDs. I was also considering white LEDs. First test was using fiber optics.
Problems in getting an even field, trying different lens, diffusors. Second
attempt was using reflectors. Since the project required a fairly compact
unit, I probably would need fluid cooling. Project stalled, but its still
in my mind.
Greg
**The largest LED array I've used is a 100 Watt array (approx 25mm X
25mm). The cooling system is a fan assisted CPU cooler. The whole lot is
almost double the size of a 250 Watt halide projector lamp (Then there's
the 33 Volt 3 Amp supply. It occupies another 100cc) and reflector. It
delivers around half as much light output as the halide lamp. It is
measurably brighter than a 500 Watt halogen flood lamp. Then there's the
33 Volt 3 Amp supply. It occupies another 100cc.
When using RGB LEDs, I've found that it is best to use a translucent
panel to mix colours.
--
Trevor Wilson
www.rageaudio.com.au