Im wanting to build my own projector and have been reading through tons of threads to get info but this forum is a little overwhelming for a noob. My first questions is what is needed to build a projector?? What I've gathered is this list
LCD
lense
fresnels
cold mirror
normal mirror
hot mirror??
type of UV blocking/filtering?
type of IR blocking/filtering?
HQI light and ballast
light box?
aspheric lense?
anything else im missing? can someone give me a brief overview or a link to a site/thread?
Im also confused about lenses..is there a specific one that should be used for something like a 7" lilliput lcd? ive seen the cheap lenses on surplusshed.com and sciplus.com and the extrememly exspensive triplet on diyprojectorcompany.com . Whats the deal?
Another thing is how screen sixe is adjusted..i have limited wall and projector space so I would need to adjust the screen size without moving my projector closer or farther away from wall ( i assume this is what everyone does). Ive seen nothing like that mentioned so i have no idea. I have some other questions that aren't coming to my head right now but these will do for now..Thanks for any help 🙂
LCD
lense
fresnels
cold mirror
normal mirror
hot mirror??
type of UV blocking/filtering?
type of IR blocking/filtering?
HQI light and ballast
light box?
aspheric lense?
anything else im missing? can someone give me a brief overview or a link to a site/thread?
Im also confused about lenses..is there a specific one that should be used for something like a 7" lilliput lcd? ive seen the cheap lenses on surplusshed.com and sciplus.com and the extrememly exspensive triplet on diyprojectorcompany.com . Whats the deal?
Another thing is how screen sixe is adjusted..i have limited wall and projector space so I would need to adjust the screen size without moving my projector closer or farther away from wall ( i assume this is what everyone does). Ive seen nothing like that mentioned so i have no idea. I have some other questions that aren't coming to my head right now but these will do for now..Thanks for any help 🙂
Hi Dan,
I was in the same boat a couple of months ago, check out these great sites:
http://www.diyprojectorphils.netfirms.com/ - Check the forum for guides
http://www.diyprojectorcompany.com/ - Check the theory pages
http://www.lumenlab.com/ - If you're willing to spend the money...
All have good guides the last 2x will sell you everything you need. Have a good read and come back to us with questions 🙂
I was in the same boat a couple of months ago, check out these great sites:
http://www.diyprojectorphils.netfirms.com/ - Check the forum for guides
http://www.diyprojectorcompany.com/ - Check the theory pages
http://www.lumenlab.com/ - If you're willing to spend the money...
All have good guides the last 2x will sell you everything you need. Have a good read and come back to us with questions 🙂
Thanks Quin, but I have seen two of the sites and the other one (diyprojectorphils) wont work right for me. I can't get into the forums. If anyone can answer anymore of my original questions I would really aprreciate it.
got into the forum and read through the guide threads and some others but some questions are still left unanswered. Thanks for any more anyone can give. 🙂
projector design in a nutshell
The match is really very simple. You can pick a lens that will give you the screen size and throw distance you need.
For every lens to screen distance, there is an LCD to lens distance that will give you a focussed image. The relationship between those two distances is determined by the strength of the projection lens:
1/focal length = 1/LCD to lens + 1/lens to screen
The magnification of an object to give you an image is the product of the two distances:
M = (lens to screen) / (LCD to lens)
So if you wanted a 70" image from a 7" LCD, then the magnification (M) would be 10. Let's say you want a 10 foot throw distance (lens to screen).
focal length = (lens to screen) / (M + 1)
focal length = 120 inches / (10 + 1) = 10.91 inches
10.91 inches * 25.4 mm / inch = 277 mm fl projection lens
You can also calculate the distance from the LCD to the lens:
10 = (lens to screen) / (LCD to lens) so
Lcd to lens = lens to screen / 10 = 12 inches
The match is really very simple. You can pick a lens that will give you the screen size and throw distance you need.
For every lens to screen distance, there is an LCD to lens distance that will give you a focussed image. The relationship between those two distances is determined by the strength of the projection lens:
1/focal length = 1/LCD to lens + 1/lens to screen
The magnification of an object to give you an image is the product of the two distances:
M = (lens to screen) / (LCD to lens)
So if you wanted a 70" image from a 7" LCD, then the magnification (M) would be 10. Let's say you want a 10 foot throw distance (lens to screen).
focal length = (lens to screen) / (M + 1)
focal length = 120 inches / (10 + 1) = 10.91 inches
10.91 inches * 25.4 mm / inch = 277 mm fl projection lens
You can also calculate the distance from the LCD to the lens:
10 = (lens to screen) / (LCD to lens) so
Lcd to lens = lens to screen / 10 = 12 inches
Oh I see, you just get a lense for the room...but has anyone used or made a zoom type thing so the throw distance could vary, but you would still have same size projection because you can adjust the lense ?
zoom lenses
Yes, some of the projection lenses now available at DIY projection website stores can be adjusted with a small lever on the side of the lens. This is not a real zoom, since the same focus is not maintained. So they are called "varifocal" lenses. But you can move the projector around a bit and then use the lever to change the focal length of the lens so you get the size image you need.
They don't change it by much: It is much more expensive to make a lens that can zoom over a large range of focal lengths without compromising performance.
Yes, some of the projection lenses now available at DIY projection website stores can be adjusted with a small lever on the side of the lens. This is not a real zoom, since the same focus is not maintained. So they are called "varifocal" lenses. But you can move the projector around a bit and then use the lever to change the focal length of the lens so you get the size image you need.
They don't change it by much: It is much more expensive to make a lens that can zoom over a large range of focal lengths without compromising performance.
- Status
- Not open for further replies.