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Old 13th September 2004, 02:22 AM   #51
go77306 is offline go77306  Canada
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Join Date: Jun 2004
Location: GTA
Quote:
Originally posted by chasse
My frensel is about a quarter of an inch larger than the LCD itself.

Thanks!

I am doing a test now... it seems the image is very dull... I didn't build a box for it yet... but bare system test, so there are some indirect/direct light on the screen.

I have a 120mm fan blow to the fresnes and lcd, fresnel is ok but I fell lcd is bit hot.


What is your distance between fresnel and lcd?
What is your distance between lamp and fresnel? (200mm?)

Thanks
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Old 6th September 2005, 02:52 AM   #52
FRIDAY is offline FRIDAY  United States
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Chasse,

In YWH's 250W lamp thread you mentioned spherical reflector in your current design; I thought you were staying with the parabolic reflector since your screenshots looked terrific.

Did anything change in your original design? Also why do you think ellipsoidal reflector will be best for your next design?
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Old 6th September 2005, 01:17 PM   #53
chasse is offline chasse  Canada
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I bought a commercial projector since and they all have ellipsoid reflector,as a mentined in the ywh message even with a 400 ansi lumen this is really bright compare to my diy setup.You cant compare with anything if you dont have a commercial one.
The spherical reflector has a parallel beam and it has to be the same size the lcd and you cant adjust the size of the beam,one more thing the heat is projected in front of it and you have to deal with it.I will buy a 250 watt ac lamp from YWH to see the difference,it might be a big improvment even with my setup.I will have to change the ballast also.I will post result.

With dichroic ellipsoid reflector it will be easier to move the lamp in or out to have a good result with the beam,even with a 15 inchs lcd and the heat is reflected back,so no heat to the lcd.
The lamp ywh found is the best you can buy because it has a very short arc and has a good color temp 6500k.I can tell you the difference is very big.The white are white not yellow and the contrast is better too.
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Old 6th September 2005, 08:46 PM   #54
FRIDAY is offline FRIDAY  United States
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I just run into something called a Circle to Rectangle light diffuser from Physical Optics Corporation; hopefully it might make things easier. Not sure about the price though. Hopefully its not an arm and leg issue.


http://www.poc.com/lsd/default.asp?p...erview&sub=ctr
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Old 4th October 2005, 12:13 AM   #55
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Interesting product... I wonder though if enough light would get through to make a decent projection. If diffused light was what we were looking for why even strip the lcd? What kind of optics would you use and where in the chain would you put it?
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Old 29th January 2006, 08:51 AM   #56
dracul is offline dracul  Brazil
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Quote:
With dichroic ellipsoid reflector it will be easier to move the lamp in or out to have a good result with the beam,even with a 15 inchs lcd and the heat is reflected back,so no heat to the lcd.
what brand is your cdm 150? How much was it?

The parabolic reflector you are using. Do you have any more photos? How much intensity did you get compared to spherical design?
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Old 29th January 2006, 08:56 AM   #57
dracul is offline dracul  Brazil
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if you use a dichroid reflector wont you need a condensor lens to spread the light for a 7 inch or larger lcd? I assume the elipsoidal would just give a spot on the back of the fresnel.
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Old 28th July 2008, 11:59 AM   #58
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HELP ME Post #20
HELLO T800

What an amazing projector? You obtained really cool results, congrats!!

Well, I'm writing from INDIA and I have done a lot of searching and read different material pertaining to DIY LCD video projectors on various sites. As far as parts are concerned, it is very hard to find good resolution LCDs, lenses, lamps here as they are too costly and are not in much demand.

I've visited your link http://allinbox.free.fr/t800/t800.htm, but as I can not read French; I could not understand much (only saw your pics to get a basic idea). It would help if you could mention those lines in English language also on that page.

Six months back I started a project like yours after obtaining a car LCD monitor/TV (TFT) of 7" size, 600*480 resolution and tried the idea of reflective projection, but in vain. Now your project motivates me to restart the work again with the concept of diassembled OHP and transmissive projection. I had to disassemble my LCD monitor and while removing its case and backlight flex cable was detached from LCD screen and some part of the screen lost its display. Please tell me if it can be repaired or it is better to buy a new monitor or LCD panel like Sharp QA-1650 with VGA. How to increase the lengths of Flex cable?

You used a 7" Lilliput XGA monitor and optical parts from a 3M OHP projector 9550, right??? I would be very grateful if you send me the complete plan/schematic of your projector design with detailed specification of each part and their placement in ATX cabinet. Please send some close up snaps with step descriptions as your project progressed as not only the final look is enough.

Especially, how did you remove backlight from LCD monitor while disassembling it, how far are LCD, lenses, mirror, Fresenels (cut off sizes?) are placed from each other in the case etc. Any other possible lighting solution you know except your 250W HQI white light?

Thanx for reading my queries, PLEASE HELP SOON before I abandon the project and think that I can never do it.

Best regards,

ASHISH DUTT

EMail: ashishdutt2001@yahoo.com
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Old 24th December 2008, 02:36 PM   #59
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chasse,
could you please post some pics of the inside of your projector? The parabolic setup interests me. Thanks.
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Old 7th April 2013, 11:39 PM   #60
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What is your color depth?
Most of the controllers I've seen claim 6/8 bit color depth.
I don't think that really is enough for an HD LCD projector.

Doug
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