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Old 6th January 2004, 09:58 PM   #41
JC-21 is offline JC-21  Canada
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Join Date: Jan 2004
Location: Burlington
Quote:
Originally posted by JC-21
OK,

So, it is a weakest link scenario. Where the LCD display will scale a DVD players' SVGA resolution OR a computers' UXGA (for argument) into the LCDs' native XGA resolution (if that is what you bought). And no matter what, the SVGA resolution from the DVD player will not neccesarily get any 'better' because of it.
- and I guess the 3-D Architectural drawings of the Off Shore Oil rig you are working at in UXGA on your computer will also be limited to the LCD panels' XGA resolution.


-Jayson-

Question #1 - Is this true?

Question #2 - Cost out, heat out, and with perfect dispersion, ie -no 'hot spot' or 'holes' - which TYPE of LIGHT is best to be 'backlighting' / modulated by our LCD panels? and... why?

A - Flourescent
B - Tungsten Halogen
C - Incandescent
D - Mercury Vapor
E - Metal Halide
F - 'Cool' / 'Warm' - will this make a difference?

I read (from searching here first) that Metal Halide is the "best" light or at least the whitest.

I should wait until all of this information gets re-organized I guess, that way - we can look in a specific spot for it.

-Jayson-
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Old 6th January 2004, 10:26 PM   #42
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Location: San Diego
I was not sure if I should buy MH so that's what I did:

1) went to homedepot and bought:
A - Flourescent
B - Tungsten Halogen
C - Incandescent
E - Metal Halide

2) tryied them

3) returned back:
A - Flourescent
B - Tungsten Halogen
C - Incandescent

$-)
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Old 7th January 2004, 12:39 AM   #43
JC-21 is offline JC-21  Canada
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Savvy.

Any information re: resolution? (above)

Then...

What makes MH the choice? Do they have a better, nicer? more even spectral output than others?

Do we need a flat spectral output, or are these just 'whiter',?

I am just becoming interested, any information is appreciated - including the Home Depot info. (I was there at lunch today myself considering Light output, Heat, Power Consumption, Type/Quality of light output.)

I understand that we are aiming for approx. 5X amount of original light to 1X projected light after passing through the Panel... So starting out with ~5,000 lumens should be OK right?, or are there other significant losses prior to or after hitting the Panel?

-Jayson-
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Old 7th January 2004, 12:46 AM   #44
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Quote:
Originally posted by JC-21
Savvy.

I understand that we are aiming for approx. 5X amount of original light to 1X projected light after passing through the Panel... So starting out with ~5,000 lumens should be OK right?, or are there other significant losses prior to or after hitting the Panel?

-Jayson-
I'm afraid 80% of light loss is a way too optimistic - at least with my Spectra C and copylens. It migth be better with LCD monitor though.
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Old 7th January 2004, 03:40 AM   #45
JC-21 is offline JC-21  Canada
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Any information re: resolution? (still above)

Yes, LCD is my intended source.

What is the transmission % of your Spectra C and copylense configuration?

Measuring the system as you must have is great news, because I was wondering how to actually work that out, aside from the postings here, which seem to use the 80%-20% rule for LCD panel sources.

Looks like the meters are ~$150.00, so I will have to hold on that for a bit myself.

I know that even if I bought one, it would only be another indication since their are thousands of different combinations of parts, with a large margin of error (hoping that each configuration were properly aligned to begin with).

I guess we could start with 10,400 lumens and then even at a 90% loss we would still have ~1,000.

I might have to build for large finned heat sinks on the backs of the lamp housings (somehow external to the main cabinet of course). - hmmm... heat sink compound...lots of surface area...aluminum extrusion - gradually thinner to the extremities, mount a 5V draw fan on there...

Is 1,000 necessary though? I've heard that you can get away with less - even half of that in a good, dark room, and nice screen.
What is your experience with this?

Thanks again for the lamp info.

-Jayson-
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Old 7th January 2004, 04:24 PM   #46
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Quote:
Originally posted by JC-21
What is the transmission % of your Spectra C and copylense configuration?

Is 1,000 necessary though? I've heard that you can get away with less - even half of that in a good, dark room, and nice screen.
What is your experience with this?
I wish I could measure it heh As far as I can tell, light I can see with my prototype setup that leaks between panel and fans are white-white while white colors projected through panel are gray-yellowish. I'd say 10% - probably all I got from my Spectra C in best case.

I tested it first with 100W Hallogen and others (crapy idea of course but I had to be sure maself )
Than I bough 70W MH (brightest MH I was able to find) and 300W halogen. They both had smthg about 2-3K lums I beleive (equal amount) and 70W MH was producing more light at the end than hallogen - probably because it had more pointed light source.
300W hal. produced so much heat - I was actualy afraid my wood box will burn. With 70W MH I sometimes forgot to turn fans on - and it was still cool.
It %#%#es me off the the former costed me $50 while later $5 only. Anyways I decide to say bye to my $100 and order 250W MH.

cc 1K lums.. goto to costco - they have their crappy $1K projector with 1K lums working during daylights with crappy screen made of painted carton box. I wish mine will do something like this one, heh..
Some people say here they can't see good picture during daytime with 250W MH (contrast of their lcds at least 1:200) - it can only means you won't even have 1K lums out of your ~10K lums 250W MH and lcd panel. Or maybe they trying to substitute their TV with projector (wishful thinking heh)

imho of course.. don't know - mine 250W is still in transit, heh will see
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Old 7th January 2004, 10:26 PM   #47
vimax is offline vimax  Romania
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I was wondering if any of you who already built a projector had a luxmeter so you would measure the light on the surface when displaying a white screen and then multiply it by the surface (in meters) to get the actual lumen output. then you can compare its brightness to a pricey projector.

I'm thinking that only 10-12% of the light flux hits the surface of the fresnel in the right direction under right conditions (9'' fl, spoon deflector). I expect the LCD to absorb at least 20% so that leaves at best 10 % of the light output of the lamp. that's ok for a 400W 30000lm MH (using a 3m or 120'' screen) but I'm having doubts about 200W MH.

Anyone tried low power (<200W) MH for a screen aprox. that size?
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Old 8th January 2004, 03:06 AM   #48
JC-21 is offline JC-21  Canada
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Sounds like ~10% is it. or at least a number we should gear up against. Thank-you for your advice. (Both)

You have most likely already checked this out, and the file size is just slightly larger than what I am allowed to attach here, otherwise I would have sent it.
I have downloaded a .pdf of the Philips line-up of Metal Halide Lamps. At least with this you get a chance to study the specifications, note the model # you are looking for, - then go after it in the real world.

www.lighting.philips.com/nam

Then search for Metal Halide and so on.

I have found that Home Depot carries a very narrow assortment of any type of anything really. Their target is of course not specialists, - it is the masses. And that is OK.

I had initially looked around there meaning to assemble (10) 12" 450 lumen 8W flourescents together in an array in order to keep the temperature very low inside the box, but they did not carry the type of light I was hoping for in that particular tube form - in that store. I wanted a 5000K CCT, & 92CRI in that size. Turns out the Philips site says there isn't such a thing anyway.
Perhaps the 4000K CCT, & 85CRI units would have been OK.
$35.00 Canadian and a few hours wiring / mounting to find out

Home Depot (Canada) has some MH's, but I would still have to go to the electrical suppy company to get the mount / supply, since Home Depot stopped carrying them for some reason... so I figured that the same electrical supply store could also provide the lamp.

Do you know... should we be concerned with the CRI value? my guess is yes - to a point. The CCT specification is a little more obvious, but there is most likely a "to a point" there too. How cool is too cool?


-Jayson-
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Old 9th January 2004, 01:39 PM   #49
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Talking stay on topic and don 't offend!

moderators here are very fickle, so refrain from having any fun at all and stick to the topic at hand!
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Old 11th January 2004, 01:41 PM   #50
JC-21 is offline JC-21  Canada
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Understood.

Vimax: Sylvania 250W Metal Halide Bulb: "ET18" 17,500 lumens when mounted vertically... 13,500 lumens when mounted horizontally. Special Ceramic fixture req'd..."Mogul" type, and use Ballast ANSI M58/E.
The drag is - it only has a 65 Colour Rendering Index, however the 4000K Colour temperature will most likely be OK. If you have got room for it, (8" long by 3" wide - "huge") and don't mind the heat - I guess this could be a brute force way to go. There is an advantage in cost, since this is a fairly common lamp used in large box department stores as overhead lighting. The complete setup was roughly $125.00 CDN, ~$82.00 USD. Still, seems like driving a dump truck to get groceries.

Alternative I am considering;
Sylvania 150W Metal Halide Bulb: "E17" in standard household 120V Med Base, and M102/O Ballast. Better CRI - 88, and slightly (and I guess I would consider marginally) cooler 4200K colour temperature. My reasons for trying this one out are that it will put out only 60% of the heat that the 250W unit will, and the size is 5-3/8" long overall by 1.5" overall wide - and it doesn't care whether you mount it Horizontally or Vertically, it will put out 11,000 lumens (mean) either way. Although I have not received an accurate price yet, this will probably be more $ than the 250W setup above since it is not as common, but I like the idea of less heat and smaller package. At 10% light transmission % of the overall projection system, I believe 1,100 should do in my particular (fairly dark) room.

-Jayson-

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