Hi everyone,
I just wanted some advice on what i was thinking about for my diy projector
heres what i want to use:
1000W MVR1000/U/BT37 lamp (arc length I beleive is 91 mm not positive if you know it please tell me)
a 550 mm field fresnel
a 330 mm condensor fresnel
a 80 mm triplet from diyprojectorcompany.
17" desktop lcd monitor
some UV + IR blocking glass
So heres my question if i set this up, with the lamp 330mm from the first fresnal, then the lcd followed by the 550 mm fresnal. Then 550mm from that i position my 80mm triplet. Will this work with any quality?
I want to use the 17" monitor because I already have that, everything else I am going to buy. I realize that the combination of fresnals with this lamp would ideally have a larger projection lens but I dont know where to look for one thats about 150mm accross. So my question is will this cause significant lose of quality? What exactly will happen if i run with the small lens?
I calculated the angle from the outermost point on lcd to the lens at 20 degrees, if i use a 330mm fresnal for the field it jumps to 33 then 45 with a 220. Whats a good angle so I dont loose the corners of my image?
Thanks for the help, I appologize if I am a n00b but I have been reading for the last 15 hours and so far i can't find solid answers to these questions.
Justin
I just wanted some advice on what i was thinking about for my diy projector
heres what i want to use:
1000W MVR1000/U/BT37 lamp (arc length I beleive is 91 mm not positive if you know it please tell me)
a 550 mm field fresnel
a 330 mm condensor fresnel
a 80 mm triplet from diyprojectorcompany.
17" desktop lcd monitor
some UV + IR blocking glass
So heres my question if i set this up, with the lamp 330mm from the first fresnal, then the lcd followed by the 550 mm fresnal. Then 550mm from that i position my 80mm triplet. Will this work with any quality?
I want to use the 17" monitor because I already have that, everything else I am going to buy. I realize that the combination of fresnals with this lamp would ideally have a larger projection lens but I dont know where to look for one thats about 150mm accross. So my question is will this cause significant lose of quality? What exactly will happen if i run with the small lens?
I calculated the angle from the outermost point on lcd to the lens at 20 degrees, if i use a 330mm fresnal for the field it jumps to 33 then 45 with a 220. Whats a good angle so I dont loose the corners of my image?
Thanks for the help, I appologize if I am a n00b but I have been reading for the last 15 hours and so far i can't find solid answers to these questions.
Justin
yes, they are wack
You have two major problems:
1. The focal length of that 80 mm diameter diyProjectorCompany projection lens is 327 mm. So it will be a bit more than 327 mm from the LCD. A 550 mm fl field fresnel will focus an image of the lamp arc around 550 mm from the LCD. Way, way off! With that projection lens, you should be using a 330 mm fl field fresnel. The 550 mm fl fresnel is designed for use with an 18" (457 mm) long throw projection lens.
2. Your lamp arc is way too long, if it is 91 mm. The size of your focussed arc image will be about:
arc length * field fresnel fl / condensor fresnel fl
With a 220 mm fl condensor fresnel and a 330 mm fl field fresnel, that would give you an arc image that is 136 mm long. (Much worse with a 550 fresnel!) You would need an enormous projection lens to get all of the light through to the screen. With an 80 mm diameter triplet, you might get 1/3 of the light through giving you effectively a 333 Watt lamp!
Try a 400 Watt lamp that has an arc no longer than 30 mm, and a 330 mm fl fresnel. Or use the 550 mm fl fresnel with an 18" opaque projection triplet or a similar long-throw triplet from one of the DIY projection stores.
You have two major problems:
1. The focal length of that 80 mm diameter diyProjectorCompany projection lens is 327 mm. So it will be a bit more than 327 mm from the LCD. A 550 mm fl field fresnel will focus an image of the lamp arc around 550 mm from the LCD. Way, way off! With that projection lens, you should be using a 330 mm fl field fresnel. The 550 mm fl fresnel is designed for use with an 18" (457 mm) long throw projection lens.
2. Your lamp arc is way too long, if it is 91 mm. The size of your focussed arc image will be about:
arc length * field fresnel fl / condensor fresnel fl
With a 220 mm fl condensor fresnel and a 330 mm fl field fresnel, that would give you an arc image that is 136 mm long. (Much worse with a 550 fresnel!) You would need an enormous projection lens to get all of the light through to the screen. With an 80 mm diameter triplet, you might get 1/3 of the light through giving you effectively a 333 Watt lamp!
Try a 400 Watt lamp that has an arc no longer than 30 mm, and a 330 mm fl fresnel. Or use the 550 mm fl fresnel with an 18" opaque projection triplet or a similar long-throw triplet from one of the DIY projection stores.
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