The difference is the focal length. The fresnel between the lamp and the LCD should have a fairly short focal length (like 220 mm). The distance between the lamp arc and the fresnel would then be about 220 mm. If you used a longer focal length fresnel, then it would have to be further from the lamp arc. Then it would collect less light. You need as much light as possible, and a 220 mm fl fresnel is optimal for this.
The fresnel between the LCD and the projection lens must have a focal length that matches the distance between the LCD and the projection lens. You can calculate that distance given the projection lens focal length and the throw distance (lens to screen):
1/x = 1/lens fl - 1/throw (all in mm)
For a throw distance of 3 meters and a projection lens with a 34 cm fl:
1/x = 1/340 - 1/3000
x = 383 mm
The closest fresnel that you can buy is a 330 mm fl.
From 3dlens, you would buy their #F220 and #F330 fresnels.
You already have a 17" LCD, so your choices are limited. But you should also have a look at these:
https://secure.lumenlab.com/shop/group.php?id=15
www.exclusiv-online.com
Your English is very good. Much better than my Swedish (since I have NO Swedish at all.)
The fresnel between the LCD and the projection lens must have a focal length that matches the distance between the LCD and the projection lens. You can calculate that distance given the projection lens focal length and the throw distance (lens to screen):
1/x = 1/lens fl - 1/throw (all in mm)
For a throw distance of 3 meters and a projection lens with a 34 cm fl:
1/x = 1/340 - 1/3000
x = 383 mm
The closest fresnel that you can buy is a 330 mm fl.
From 3dlens, you would buy their #F220 and #F330 fresnels.
You already have a 17" LCD, so your choices are limited. But you should also have a look at these:
https://secure.lumenlab.com/shop/group.php?id=15
www.exclusiv-online.com
Your English is very good. Much better than my Swedish (since I have NO Swedish at all.)
Ok, i thing im starting to understand what i should have.
Hers the deal: I Buy 2 fresnel lenses from 3dlens.com one 220 mm and one 330 mm. I also buy a lamp (bulb) from lummenlab.com (400w recommeded). Heres the question: Is it accepteble to use a fresnel with a focal length of 330 mm with a projektor lens from lumenlab.com with a focal lenght of 320 mm? It?0…7s just 10 mm, is that sufficient?
/Thanks guy for taking your time helping me. Much appreciate!
Hers the deal: I Buy 2 fresnel lenses from 3dlens.com one 220 mm and one 330 mm. I also buy a lamp (bulb) from lummenlab.com (400w recommeded). Heres the question: Is it accepteble to use a fresnel with a focal length of 330 mm with a projektor lens from lumenlab.com with a focal lenght of 320 mm? It?0…7s just 10 mm, is that sufficient?
/Thanks guy for taking your time helping me. Much appreciate!
It would be better if you could find a fresnel that had a bit longer focal length. You can use the equation I gave earlier to calculate exactly the LCD-to-projector lens distance for your throw distance and any projection lens. For a 320 mm fl lens, that distance will probably be between 340 and 380 mm.
I don't think there is a fresnel available with that focal length. 330 mm is close enough. You can adjust the lamp-to-fresnel distance by a few millimeters to compensate.
If you were building a projector using a 7" or 8" LCD, then a condensor lens would collect more light. With a 17" LCD, it will not make much difference so you should not bother with it. But you should get a good spherical reflector. The DIY projector sites sell them, or you can use the polished aluminum napkin holder from IKEA.
I don't think there is a fresnel available with that focal length. 330 mm is close enough. You can adjust the lamp-to-fresnel distance by a few millimeters to compensate.
If you were building a projector using a 7" or 8" LCD, then a condensor lens would collect more light. With a 17" LCD, it will not make much difference so you should not bother with it. But you should get a good spherical reflector. The DIY projector sites sell them, or you can use the polished aluminum napkin holder from IKEA.
Question about anti-glare and fresnels again!
Ok, just started my project. I have buildt a projector box and next to do is to buy some lenses. Today i removed my anti-glare (Polarizer) successfuly (ihope). Then when i did a "check run" on my LCD i discovered that i didnt get any picture! Oh no i thought, now im screwed! Then when i tryed my last hope i could finally breath out. I discovered that something in the anti-glare thing was important. I held my anti-glare infront of the screen and a picture was visible.
Question: is the picture goin to be visible in the projection? Or do i need to buy a new one?
BTW: Looked on a tutorial, but it didnt say something about this issue.
Again sorry for my bad english.
/Thanks!
Ok, just started my project. I have buildt a projector box and next to do is to buy some lenses. Today i removed my anti-glare (Polarizer) successfuly (ihope). Then when i did a "check run" on my LCD i discovered that i didnt get any picture! Oh no i thought, now im screwed! Then when i tryed my last hope i could finally breath out. I discovered that something in the anti-glare thing was important. I held my anti-glare infront of the screen and a picture was visible.
Question: is the picture goin to be visible in the projection? Or do i need to buy a new one?
BTW: Looked on a tutorial, but it didnt say something about this issue.
Again sorry for my bad english.
/Thanks!
Hmm, A good lesson in polarization. It been a while for me on the diy projection topic, but sounds to me like a polarizing sheet of film off the LCD. This changes the alignment of the light for the human eye to see it. Yes you will need that sheet even when projecting. If the sheet is destroyed there is a cheap trick. 3M gives out free 7X10 samples . Just takes a little research on their site. 3m sells all sorts of cool films that can work great for diy projectors. I bet if you were to wear a nice pair of sunglasses you could see the image just fine.
. Just takes a little research on their site. 3m sells all sorts of cool films that can work great for diy projectors. I bet if you were to wear a nice pair of sunglasses you could see the image just fine.
Polarization is how the LCD works: Light enters the glass sandwich with one polarity (from the first polarization filter). The liguid crystal twists the polarity to some extent. (The amount of twist depends on the charge across the liquid crystal in each cell.) When the light leaves the glass sandwich it strikes another polarization filter. If the light's polarity matches the second filter, then it passes. If it is 90 degrees off, then it mostly gets absorbed. Values in between give the different shades.
You need that second filter, but it doesn't have to be right against the glass like the original was. I think you could just put a polarization filter on the projection lens. (You would have to rotate it until the contrast is maximal.) Or you could even project the unfiltered light onto your screen, but view it through polarized glasses. That would be pretty cool because it would look just like a bright white screen to everybody without the "viewing glasses"!
You could even project two different images on the screen at the same time. One projector would use a second filter polarized in the verticle direction, and the other in the horizontal direction. Use the horizontal glasses to see one image, the verticle glasses to see the other. This is the basis of color 3-D projection.
Try some experiments. Have some fun.
You need that second filter, but it doesn't have to be right against the glass like the original was. I think you could just put a polarization filter on the projection lens. (You would have to rotate it until the contrast is maximal.) Or you could even project the unfiltered light onto your screen, but view it through polarized glasses. That would be pretty cool because it would look just like a bright white screen to everybody without the "viewing glasses"!
You could even project two different images on the screen at the same time. One projector would use a second filter polarized in the verticle direction, and the other in the horizontal direction. Use the horizontal glasses to see one image, the verticle glasses to see the other. This is the basis of color 3-D projection.
Try some experiments. Have some fun.
For newbies post #27
Great info, thanks tones. After reading everything till my eyes bulged out of my head...he he he. I put together a projection system; here it is,
overhead= DA-Lite 5000 also used an Elmo HP4K by Dukane 4000
LCD Panel= Nview Z115
screen= home made 72" x 112"
Sanyo Home theater DVD 5.1 player
WOW! WOW! WOW! my family thinks it's great, and my kids now play the PS2 games on it. Thanks to all here for educating me to the point
where I could do this. Please keep up the great work.
Great info, thanks tones. After reading everything till my eyes bulged out of my head...he he he. I put together a projection system; here it is,
overhead= DA-Lite 5000 also used an Elmo HP4K by Dukane 4000
LCD Panel= Nview Z115
screen= home made 72" x 112"
Sanyo Home theater DVD 5.1 player
WOW! WOW! WOW! my family thinks it's great, and my kids now play the PS2 games on it. Thanks to all here for educating me to the point
where I could do this. Please keep up the great work.
verbose mustafa said:
Ok, I was just browsing around this thread, and I think you may be able to use LED's....
Later on you state that 4000 lumens is a good figure, and cree XR-E leds are 100 lumens each.
If you had 40 x XR-E leds, each with thier own optics/reflectors, then 4000 lumens from led's might be possible...
It would be expensive and fiddly, but it just might work!
There are LED-based projectors: They project very small and not very bright images. Contrary to popular thought, LEDs are not the most efficient light sources! Compact fluorescent lamps are better, and Metal Halide are even more efficient than CFL. The only standard available lamp that is more efficient that a MH lamp is a low pressure sodium lamp (which is useless for projection because of its poor spectrum).
So if you put together enough LEDs to make a competitive projector, you will generate a lot of unwanted heat and spend many many times more than you would for a MH lamp-based projector. Your LED projector will also use more power to generate the same size and brightness of image.
Then there's the problem of Conservation of Etendue: Your array of LEDs will "look" like a very large light source, since the rays emitted by each LED will have different origins. There is no reasonable way to reflect or refract such a "beam" into a set of parallel rays. The net result is that each pixel on the screen will be illuminated by rays passing through all areas of the projection lens. (And quite a few of those rays will not even reach the projection lens.) All the possible distortions and aberrations in the lens will smear each LCD pixel over a wider area of the screen. The resulting image will be blurry.
When you use a point-source lamp, (or at least as small as possible) then each screen pixel will be illuminated by rays that only pass through a very small area of the lens. A less-than- perfect lens can still give you a very sharp image because the distortions and aberrations are much smaller if the rays only use a small area. This is similar to using a small aperature on a camera to get a deeper field in focus.
LEDs will become competitive when you can get one that emits 10000 lumens from a very small point, in a cone that matches the focal length of an available fresnel. But before that happens, you might be able to just buy an active-matrix color LED display that would not need any other lamp for projection.
So if you put together enough LEDs to make a competitive projector, you will generate a lot of unwanted heat and spend many many times more than you would for a MH lamp-based projector. Your LED projector will also use more power to generate the same size and brightness of image.
Then there's the problem of Conservation of Etendue: Your array of LEDs will "look" like a very large light source, since the rays emitted by each LED will have different origins. There is no reasonable way to reflect or refract such a "beam" into a set of parallel rays. The net result is that each pixel on the screen will be illuminated by rays passing through all areas of the projection lens. (And quite a few of those rays will not even reach the projection lens.) All the possible distortions and aberrations in the lens will smear each LCD pixel over a wider area of the screen. The resulting image will be blurry.
When you use a point-source lamp, (or at least as small as possible) then each screen pixel will be illuminated by rays that only pass through a very small area of the lens. A less-than- perfect lens can still give you a very sharp image because the distortions and aberrations are much smaller if the rays only use a small area. This is similar to using a small aperature on a camera to get a deeper field in focus.
LEDs will become competitive when you can get one that emits 10000 lumens from a very small point, in a cone that matches the focal length of an available fresnel. But before that happens, you might be able to just buy an active-matrix color LED display that would not need any other lamp for projection.
Re: For newbies post #27
The z115 is a great panel. How much did you pay for it? Back in the day when they where popular around here I used to buy untested panels for $20 and resell them for much more! I got to test almost all of them including the infamous sharp qa-2500. My fav panel was the z115/z215 series. Glad everything worked out great.
Well put, I think this is the best way it has ever been explained. I remember researching the super bright leds and my mouth hit the floor when I saw how much heat they put out. I have projected in image with nothing more then an lcd back light. To get a 500 ansi lumen image though, probably not any time soon. Thanks for the great post.
nzshy said:Great info, thanks tones. After reading everything till my eyes bulged out of my head...he he he. I put together a projection system; here it is,
overhead= DA-Lite 5000 also used an Elmo HP4K by Dukane 4000
LCD Panel= Nview Z115
screen= home made 72" x 112"
Sanyo Home theater DVD 5.1 player
WOW! WOW! WOW! my family thinks it's great, and my kids now play the PS2 games on it. Thanks to all here for educating me to the point
where I could do this. Please keep up the great work.
The z115 is a great panel. How much did you pay for it? Back in the day when they where popular around here I used to buy untested panels for $20 and resell them for much more! I got to test almost all of them including the infamous sharp qa-2500. My fav panel was the z115/z215 series. Glad everything worked out great.
Guy Grotke said:
Well put, I think this is the best way it has ever been explained. I remember researching the super bright leds and my mouth hit the floor when I saw how much heat they put out. I have projected in image with nothing more then an lcd back light. To get a 500 ansi lumen image though, probably not any time soon. Thanks for the great post.
HELP on BULB
Hi All
I am unable to get MH with Ballast at my place, the dealer has offered few alternatives.
1. Philips Aluline Pro 37/56 mm
Product Description
• Low-voltage halogen burner in a lightweight, high-gloss anodised aluminium reflector giving a white halogen light
Product Feature
• Integrated protective front glass
• Choice of clear or frosted glass
• High-intensity beam with an extremely clearly defined beam shape (clear glass versions only)
• Excellent color rendering
Product Benefit
• Excellent accent lighting effects due to reduced spill light (clear
versions only) Application
• Excellent light source for accent and general lighting in shops,
home, restaurants, galleries, exhibitions and museums
Rated Lamp Wattage: 35W
Beam Angle : 6D
Lumens Intensity: 18000
Rated Voltage : 6V
Another Choice
Philips MASTERColour CDM-R 35W/942 E27 PAR20L 10D
Watt : 39W
Voltage : 85
Color Tempeature : 4200
Chromaticity Coordinated : x - 371, y - 366
Luminous Intensity : 21500
Beam Angle - 7.5D, Spot
Option3
Philips MASTERColour CDM-R 70W/942 E27 PAR20L 30D
Watt : 73W
Voltage : 88
Color Tempeature : 4200
Chromaticity Coordinated : x - 371, y - 366
Luminous Intensity : 13000
Beam Angle - 26D, Narrow Flood
Please help me in taking a decision
Regards
Naidu
Hi All
I am unable to get MH with Ballast at my place, the dealer has offered few alternatives.
1. Philips Aluline Pro 37/56 mm
Product Description
• Low-voltage halogen burner in a lightweight, high-gloss anodised aluminium reflector giving a white halogen light
Product Feature
• Integrated protective front glass
• Choice of clear or frosted glass
• High-intensity beam with an extremely clearly defined beam shape (clear glass versions only)
• Excellent color rendering
Product Benefit
• Excellent accent lighting effects due to reduced spill light (clear
versions only) Application
• Excellent light source for accent and general lighting in shops,
home, restaurants, galleries, exhibitions and museums
Rated Lamp Wattage: 35W
Beam Angle : 6D
Lumens Intensity: 18000
Rated Voltage : 6V
Another Choice
Philips MASTERColour CDM-R 35W/942 E27 PAR20L 10D
Watt : 39W
Voltage : 85
Color Tempeature : 4200
Chromaticity Coordinated : x - 371, y - 366
Luminous Intensity : 21500
Beam Angle - 7.5D, Spot
Option3
Philips MASTERColour CDM-R 70W/942 E27 PAR20L 30D
Watt : 73W
Voltage : 88
Color Tempeature : 4200
Chromaticity Coordinated : x - 371, y - 366
Luminous Intensity : 13000
Beam Angle - 26D, Narrow Flood
Please help me in taking a decision
Regards
Naidu
MH lamp source
These lamps will not give you a bright image. They might work for a small screen image in a dark room. Can you buy online? Here is a good place to buy MH with ballast, and also anything else you need:
www.exclusiv-online.com
These lamps will not give you a bright image. They might work for a small screen image in a dark room. Can you buy online? Here is a good place to buy MH with ballast, and also anything else you need:
www.exclusiv-online.com
Few more options
Metal Halide - Double ended with 150Watt power and 4200K color output, 12500lm lumens, 12000 hrs life
how about this options
GE Ceramic Metal Halide – PAR 64
watts: 150Watts
Color : 4200K
Lumens : 154000lm
Life: 8000hrs
CRI RA - 90+ (Colour rendering index)
I thisk this bulb should be a better choice
Metal Halide - Double ended with 150Watt power and 4200K color output, 12500lm lumens, 12000 hrs life
how about this options
GE Ceramic Metal Halide – PAR 64
watts: 150Watts
Color : 4200K
Lumens : 154000lm
Life: 8000hrs
CRI RA - 90+ (Colour rendering index)
I thisk this bulb should be a better choice
Bulb Link
Sorry I forgot to post the link
http://genet.gelighting.com/LightPr...led Beam^Stage _, Studio&SearchFieldCode=null
Sorry I forgot to post the link
http://genet.gelighting.com/LightPr...led Beam^Stage _, Studio&SearchFieldCode=null
Dead lcd Please Help
guys, i have got a pretty big problem,
I purchase super brand lcd tv 9.2" res-800x256. With built in tuner, I purchase it for 4200/-Rs.(100$)
Vga & video connectivity
while stripping the lcd i destroyed it , The lcd is not working now.
i am in a fix now.
I was Making the projector for a friend, Now he wont be able to buy new set.
i have the controllers . i looked throughly and found that the controller is
based on techwell inc chip TW 8816.
I downloade the data sheet it specifies that the chip supports wxga . but the
lcd which came as package was only 800x256.
So is it possibe that i buy some other wxga lcd and connect to this controller,
will it work.
Kindly suggest if there is any compatible lcd, Will laptop lcd work .
laptop lcd's have great resolution in small size.
all the gurus present here please help.
guys, i have got a pretty big problem,
I purchase super brand lcd tv 9.2" res-800x256. With built in tuner, I purchase it for 4200/-Rs.(100$)
Vga & video connectivity
while stripping the lcd i destroyed it , The lcd is not working now.
i am in a fix now.
I was Making the projector for a friend, Now he wont be able to buy new set.
i have the controllers . i looked throughly and found that the controller is
based on techwell inc chip TW 8816.
I downloade the data sheet it specifies that the chip supports wxga . but the
lcd which came as package was only 800x256.
So is it possibe that i buy some other wxga lcd and connect to this controller,
will it work.
Kindly suggest if there is any compatible lcd, Will laptop lcd work .
laptop lcd's have great resolution in small size.
all the gurus present here please help.
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