reference
Hi guys,
Here I posted link, thank's to SushiMasterX from Small Panel projector thread:
http://www.oes.itri.org.tw/en/ptv-e.htm
Summary:
LCD panel swallow 2/3 of the light.
single panel type has lower resolution (cause it requires RGB pixels in a single panel, and requires color filters) lower brightness (because of the filter will absorb 2/3 of the light).
MH light is the most efficient so far.
The system urgently requires a high efficiency, short arc gap, long lifetime metal halide lamp.
Reflector
Spherical mirror mostly use on single panel LCD projection system.
Is this same as fresnel panel?
Integrator to uniform the distribution of light, and convert the circular illumination area into a rectangular area as the LCD panel.
big size PCX lens should be a good choice
the projection lens needs to have long back focal length, larger relative aperture, and the collection efficiency needs to be higher.
is this called a hotspot?
The development of uniformity is even faster, in the early days the uniformity is between 30% to 50% without integrator.
The increase of uniformity also improves the non uniformity of the light difference chromatic aberration on the screen.
Don't laugh!
Another noticeable thing is reflective type LCD projector, as shown in fig. 4, the term reflective means the LCD panel is the reflective type.
We're on the right track
the rear projector is more appropriate than the front projector for home use, and big screen, flattened, high resolution are always TV orientations.
Sony too, using big panel like us
The other way is to maintain the pixel area and increase the panel area, like in SONY, SVGA is 1.3¡¨, XGA is 1.8¡¨, and SXGA is 2.4¡¨, the system become larger as the panel area increases.
Hi guys,
Here I posted link, thank's to SushiMasterX from Small Panel projector thread:
http://www.oes.itri.org.tw/en/ptv-e.htm
Summary:
LCD panel swallow 2/3 of the light.
single panel type has lower resolution (cause it requires RGB pixels in a single panel, and requires color filters) lower brightness (because of the filter will absorb 2/3 of the light).
MH light is the most efficient so far.
The system urgently requires a high efficiency, short arc gap, long lifetime metal halide lamp.
Reflector
Spherical mirror mostly use on single panel LCD projection system.
Is this same as fresnel panel?
Integrator to uniform the distribution of light, and convert the circular illumination area into a rectangular area as the LCD panel.
big size PCX lens should be a good choice
the projection lens needs to have long back focal length, larger relative aperture, and the collection efficiency needs to be higher.
is this called a hotspot?
The development of uniformity is even faster, in the early days the uniformity is between 30% to 50% without integrator.
The increase of uniformity also improves the non uniformity of the light difference chromatic aberration on the screen.
Don't laugh!
Another noticeable thing is reflective type LCD projector, as shown in fig. 4, the term reflective means the LCD panel is the reflective type.
We're on the right track
the rear projector is more appropriate than the front projector for home use, and big screen, flattened, high resolution are always TV orientations.
Sony too, using big panel like us
The other way is to maintain the pixel area and increase the panel area, like in SONY, SVGA is 1.3¡¨, XGA is 1.8¡¨, and SXGA is 2.4¡¨, the system become larger as the panel area increases.
Sorry to hear about your problems, undream. I think that your MH bulb is definately bright enough though. If a 2200 lumen OHP was bright enough to watch TV and movies in a darkened room for me, then your bulb should be more than enough, it just needs a reflector. keep in mind that a good reflector can double or triple the light output to the LCD and eventually the image. Just a thought.
1000W
Undream,
When I first started out, I went from a 400w to 1000w because I didn't think that I was getting enough light. I have now switched back to 400w and am going to try to get a more efficient use of the light. I may switch back if I end up with the same problems as you. Just to let you know, the reasons that I switched back to 400w were that the heat was quite a bit more with a 1000w and although it could be addressed, I wanted to avoid it if possible. Also, the bulb is much bigger, which makes for a much larger reflection box. Finally, the ballast that I had, made a considerable amount of noise, so I probably would have needed to place the ballast and housing in a remote location and then run the socket wires to the projector. It was a brand new ballast and housing, but the noise was comparable to an old refrigerator, although some may be quieter, I think that a louder hum is just the nature of what one can expect from the 1000w variety.
None of the issues that I found are insurmountable, but I just wanted to give you a heads up on what I had experienced so you can take that into account.
Undream,
When I first started out, I went from a 400w to 1000w because I didn't think that I was getting enough light. I have now switched back to 400w and am going to try to get a more efficient use of the light. I may switch back if I end up with the same problems as you. Just to let you know, the reasons that I switched back to 400w were that the heat was quite a bit more with a 1000w and although it could be addressed, I wanted to avoid it if possible. Also, the bulb is much bigger, which makes for a much larger reflection box. Finally, the ballast that I had, made a considerable amount of noise, so I probably would have needed to place the ballast and housing in a remote location and then run the socket wires to the projector. It was a brand new ballast and housing, but the noise was comparable to an old refrigerator, although some may be quieter, I think that a louder hum is just the nature of what one can expect from the 1000w variety.
None of the issues that I found are insurmountable, but I just wanted to give you a heads up on what I had experienced so you can take that into account.
1000W is definitly overkill. You will have a horrible heat issue to deal with wich equals noise and a hot room. You need to work at a more efficient use of light......my personal idea wich i havent tried out het is to simply get a stage ellipsoidal light...gut the bulb and put a 400W MH into it.......you get an elliptical light with a variable focus lens on the front and you should get some awesome results......its much along the lines of Marklar's setup...he uses an elliptical downlight, using a stage ellipsoidal will give you a much larger aperature to let the light come out than with Marklar's setup (wonderfull as it is).
Personally if i didnt have 2 bulbless projectors to work on I'd buy a cheap stage ellipsoidal and do the panel thing with it.
Personally if i didnt have 2 bulbless projectors to work on I'd buy a cheap stage ellipsoidal and do the panel thing with it.
alternative CHEAP lighting
Hey peeps,
I was at home depot the other day looking throught some ligting fixtures and ran across a few bulbs with the following specs:
Bulb Application:
Halogen/Quartz Bulbs
Watts: 350 watts
Volts: 120VOLTS
Base Type: Recessed Single Contact
Life: 3000 hrs.
Lumens: 10,000
Nominal Length: 4.69"
Manufacturer: General Electric Co.
SKU #: 494152
UPC #: 043168122832
Price $7.99
------------------------------------------------------------------------------
Bulb Application: Halogen/Quartz Bulbs
Watts: 500 watts
Volts: 120VOLTS
Base Type: Recessed Single Contact
Life: 2000 hrs.
Lumens: 11100
Nominal Length: 4.69"
Manufacturer: General Electric Co.
SKU #: 742597
UPC #: 043168993807
Price $4.97
------------------------------------------------------------------------------
Seems to me like these might work since they are small, powerfull, cheap, and widely available
ap0the0sis
Hey peeps,
I was at home depot the other day looking throught some ligting fixtures and ran across a few bulbs with the following specs:
Bulb Application:
Halogen/Quartz Bulbs
Watts: 350 watts
Volts: 120VOLTS
Base Type: Recessed Single Contact
Life: 3000 hrs.
Lumens: 10,000
Nominal Length: 4.69"
Manufacturer: General Electric Co.
SKU #: 494152
UPC #: 043168122832
Price $7.99
------------------------------------------------------------------------------
Bulb Application: Halogen/Quartz Bulbs
Watts: 500 watts
Volts: 120VOLTS
Base Type: Recessed Single Contact
Life: 2000 hrs.
Lumens: 11100
Nominal Length: 4.69"
Manufacturer: General Electric Co.
SKU #: 742597
UPC #: 043168993807
Price $4.97
------------------------------------------------------------------------------
Seems to me like these might work since they are small, powerfull, cheap, and widely available
ap0the0sis
problem with those quartz halogen things are they are way way to hot......you remember the fires that the halogen torch lamps caused....now there are protective screens over them. Also, with those lamps we are looking at a ribbon of light 2-3 inches long wich by no means close to a point light source so you are almost guaranteed light loss. Enclosing these in a container that isn't metal is asking for trouble IMHO. And even then the heat is still too much
Hi Guys,
Undream,
sorry to hear about your problems - you are one if the inspriations on this site!
There must be a better way to feed light into one of these panels than what most people are doing - I believe that if we can perfect the light source, then fantastic things will happen!
I believe that raw power is not the best way. The single panel system is horribly inefficient compared with the three panel designs, but it does work! Quite well! (Though it does seem that 400 watts are required to drive it - my original setup started with a Sharp QA 1100 on a Dukane Sunsplash with a 400 Watt FXL bulb. It works, even though the bulb is only halogen because the bulb is small enough to be effectively focussed.)
The original revolution in desktop projectors, which brought them into the mainstream, was the Proxima 2800 - using the same FXL with a 6.3" RGB panel. In its later incarnation they squezed 300 ANSI lumens out of it!
There must be a way to capture the light effectively, and I really believe that a smaller, (possibly lower-power) bulb, if it's light output were more effectively used, could give better results than many of the 400 Watt MH beasts (Marklar's excepted...)
I am currently awaiting a couple of prisms from Surplus Shack so that I can explore using them to merge multiple small collimated beams into one. My current light sources are only 55 Watt Fog Projector lamps with a condenser on the front (VERY collimated - small filament bulbs), but if things work, I could up the power rating of the bulbs (110 Watt), put four of them together, and have a lumen equivalent of a single FXL, but using much cheaper and longer life bulbs... It is a long shot, but it might open alternative doors...
It may, or may not be the answer, but while the 400 Watt MH bulbs are bright, it seems VERY hard to use many of the lumens generated.
Gunawan,
I did continue the experiment with the fresnel after the panel, and it is now my default configuration... I DID cheat on one setup, though - rather than order a $40 fresnel from Fresnel-tech, I gutted that Proxima 9100 projector, and put the electronics & panel from a Spectra C in there. Beautiful!!! (The 9100 is effectively an OHP with LCD panel integrated inside, behind a single fresnel...)
My other unit, with a cheap page magnifier raised over the LCD on my modified OHP is still there, but the Fresnel is not as good as the proxima, and I use a large 6" DCV lens between the fresnel and the OHP objective to reduce the "zoom" factor (including the fresnel into the optical path magnifies the projected image - as any good magnifier should - but the result is just too big for me...)
There is unfortunately some chromatic aberation introduced by the DCV, and I am currently waiting for some decent PCV/PCX cylindrical lenses to arrive so I can experiment with generating a widescreen image from a 4:3 panel... So, this rig is strictly experimental... Once things stabilise, I will probably do something to the main OHP objective to reduce the overall zoom without the chromatic aberations.
The 9100 has some interesting other optics too, though - they use non-linear front-sided fresnel prism mirrors to shape the light beam (from a narrow collimated beam, to a wide collimated beam). This allows them to reduce the height of the unit, but is interesting in that they are effectively using fresnel micro-prism technology to shape the beam from the bulb, and spread it out - this appears to give a more uniform light distribution than the fresnel lenses in an OHP...
Interesting stuff!!!
Keep at it everybody - you guys are awesome, and we are all very close to success!!!
Bill.
Undream,
sorry to hear about your problems - you are one if the inspriations on this site!
There must be a better way to feed light into one of these panels than what most people are doing - I believe that if we can perfect the light source, then fantastic things will happen!
I believe that raw power is not the best way. The single panel system is horribly inefficient compared with the three panel designs, but it does work! Quite well! (Though it does seem that 400 watts are required to drive it - my original setup started with a Sharp QA 1100 on a Dukane Sunsplash with a 400 Watt FXL bulb. It works, even though the bulb is only halogen because the bulb is small enough to be effectively focussed.)
The original revolution in desktop projectors, which brought them into the mainstream, was the Proxima 2800 - using the same FXL with a 6.3" RGB panel. In its later incarnation they squezed 300 ANSI lumens out of it!
There must be a way to capture the light effectively, and I really believe that a smaller, (possibly lower-power) bulb, if it's light output were more effectively used, could give better results than many of the 400 Watt MH beasts (Marklar's excepted...)
I am currently awaiting a couple of prisms from Surplus Shack so that I can explore using them to merge multiple small collimated beams into one. My current light sources are only 55 Watt Fog Projector lamps with a condenser on the front (VERY collimated - small filament bulbs), but if things work, I could up the power rating of the bulbs (110 Watt), put four of them together, and have a lumen equivalent of a single FXL, but using much cheaper and longer life bulbs... It is a long shot, but it might open alternative doors...
It may, or may not be the answer, but while the 400 Watt MH bulbs are bright, it seems VERY hard to use many of the lumens generated.
Gunawan,
I did continue the experiment with the fresnel after the panel, and it is now my default configuration... I DID cheat on one setup, though - rather than order a $40 fresnel from Fresnel-tech, I gutted that Proxima 9100 projector, and put the electronics & panel from a Spectra C in there. Beautiful!!! (The 9100 is effectively an OHP with LCD panel integrated inside, behind a single fresnel...)
My other unit, with a cheap page magnifier raised over the LCD on my modified OHP is still there, but the Fresnel is not as good as the proxima, and I use a large 6" DCV lens between the fresnel and the OHP objective to reduce the "zoom" factor (including the fresnel into the optical path magnifies the projected image - as any good magnifier should - but the result is just too big for me...)
There is unfortunately some chromatic aberation introduced by the DCV, and I am currently waiting for some decent PCV/PCX cylindrical lenses to arrive so I can experiment with generating a widescreen image from a 4:3 panel... So, this rig is strictly experimental... Once things stabilise, I will probably do something to the main OHP objective to reduce the overall zoom without the chromatic aberations.
The 9100 has some interesting other optics too, though - they use non-linear front-sided fresnel prism mirrors to shape the light beam (from a narrow collimated beam, to a wide collimated beam). This allows them to reduce the height of the unit, but is interesting in that they are effectively using fresnel micro-prism technology to shape the beam from the bulb, and spread it out - this appears to give a more uniform light distribution than the fresnel lenses in an OHP...
Interesting stuff!!!
Keep at it everybody - you guys are awesome, and we are all very close to success!!!
Bill.
Best Light
I'll reply to the 'best light' question just to let you guys know I'm still alive out here. It's METAL HALIDE baby and the 400 Watt variety seems to be the one of choice. Now that I've addressed another newbie question (do you guys realize there is a several hundred page thread that answers these 'basic' issues? just wondering....)
Anyway, I got my NView Viewframe fired up and it works fine. I'm just waiting to get my hands on an overhead projector. I want to see what an 'out of box' setup can do before I get DIY crazy and start freakin' over optics/reflectors etc. I've decided to commit my setup to an outdoor (deck) environment so looks aren't going to be as big a factor. I just have to make sure it's waterproof.
In the end, I think I'm going to end up (GASP) buying one of the mid range commercial projectors to use in the house. Either that, or refinance my life and get a plasma....
Enjoy.
I'll reply to the 'best light' question just to let you guys know I'm still alive out here. It's METAL HALIDE baby and the 400 Watt variety seems to be the one of choice. Now that I've addressed another newbie question (do you guys realize there is a several hundred page thread that answers these 'basic' issues? just wondering....)
Anyway, I got my NView Viewframe fired up and it works fine. I'm just waiting to get my hands on an overhead projector. I want to see what an 'out of box' setup can do before I get DIY crazy and start freakin' over optics/reflectors etc. I've decided to commit my setup to an outdoor (deck) environment so looks aren't going to be as big a factor. I just have to make sure it's waterproof.
In the end, I think I'm going to end up (GASP) buying one of the mid range commercial projectors to use in the house. Either that, or refinance my life and get a plasma....
Enjoy.
ajira99
You shouldn't need a massive optical cavity - especially if you are using a fresnel after the panel. The biggest problem with the fresnel placed just far enough from the panel to avoid moire effects, is that it magnifies the panel. One of the good side effects of this, though, is that it effectively increases the distance of the LCD from the objective lens (the virtual image produced is further away from the objective than the physical LCD), allowing the objective to be moved closer. (Another way of looking at this is that the fresnel and objective can be combined mathematically into a single virtual lens with reduced focal length... See the Excell calculators from the previous thread for details!)
If your light path is still too long, you could always use mirrors to "fold" the optical path a couple of times...
Otherwise, Gunawan gave a nice and precise set of directions for positioning the lenses in this configuration, including distances etc. earlier in this thread, and my experience (let the flames begin ) is that this arrangement makes better use of the light coming through the LCD panel, than a small objective lens alone.
(Putting a fresnel between the light source and the LCD is intended to shape the beam of light emerging from the LCD panel into a cone, so that most of the light "should" pass through the objective. But, this arrangement was never designed to be used with LCD panels - it was designed to be used with transparencies that don't interfere with the path of the light travelling through them - they are effectively simple filters... Many LCD panels DO interfere with this beam shaping arrangement due to microscopic lenses being built into the panel itself as an attempt to maximise the light throughput and increase LCD viewing angle... Thus, light emerging from the LCD panel might never be seen by the objective - reducing the intensity of the projected image...)
My configuration is not perfect, because good fresnels are expensive, and most people (myself included) are playing with cheap page magnifiers, or the coarse ones from cannibalised OHP units. And, of course, a good fresnel is not as good as a good PCX...
There is still much for us all to learn here!!!
But, it IS good fun!
Bill.
You shouldn't need a massive optical cavity - especially if you are using a fresnel after the panel. The biggest problem with the fresnel placed just far enough from the panel to avoid moire effects, is that it magnifies the panel. One of the good side effects of this, though, is that it effectively increases the distance of the LCD from the objective lens (the virtual image produced is further away from the objective than the physical LCD), allowing the objective to be moved closer. (Another way of looking at this is that the fresnel and objective can be combined mathematically into a single virtual lens with reduced focal length... See the Excell calculators from the previous thread for details!)
If your light path is still too long, you could always use mirrors to "fold" the optical path a couple of times...
Otherwise, Gunawan gave a nice and precise set of directions for positioning the lenses in this configuration, including distances etc. earlier in this thread, and my experience (let the flames begin
) is that this arrangement makes better use of the light coming through the LCD panel, than a small objective lens alone. (Putting a fresnel between the light source and the LCD is intended to shape the beam of light emerging from the LCD panel into a cone, so that most of the light "should" pass through the objective. But, this arrangement was never designed to be used with LCD panels - it was designed to be used with transparencies that don't interfere with the path of the light travelling through them - they are effectively simple filters... Many LCD panels DO interfere with this beam shaping arrangement due to microscopic lenses being built into the panel itself as an attempt to maximise the light throughput and increase LCD viewing angle... Thus, light emerging from the LCD panel might never be seen by the objective - reducing the intensity of the projected image...)
My configuration is not perfect, because good fresnels are expensive, and most people (myself included) are playing with cheap page magnifiers, or the coarse ones from cannibalised OHP units. And, of course, a good fresnel is not as good as a good PCX...
There is still much for us all to learn here!!!
But, it IS good fun!
Bill.
woneill. the panels which we are talking about surely don't have microscopic lenses. Microsopic lens arrays (MLA) came up in the late 90s, but were mostly used in 3 panel projectors. I never heard of them being built in projection panels for OHPs, which most DIYers are using here. If they would exist in these panels, you wouldn't see anything looking throug them! And they wouln't work with traditional OHPs!
xblocker
reflector
hi guys
Has anyone thought about going down the local breakers yard
and getting a spotlamp off an old car and fitting there own light
in it, the reflectors in headlight and spotlamps come in all shapes
and sizes i'm sure theres somthing we could use, cheep too.
I have decided to get one of those halegen capsule bulbs and try it out 300watt 240v no balest needed
http://www.ecwuk.com/disco_lighting/lamps/
my projector at the moment is 20" long 13" wide and 16"high
at its highest point
I'm using an ask impack 24 panel,wich has an 8 1/2 inch lcd
I still need to get a decent lense.
anyone in the uk know of a good place for lenses
hi guys
Has anyone thought about going down the local breakers yard
and getting a spotlamp off an old car and fitting there own light
in it, the reflectors in headlight and spotlamps come in all shapes
and sizes i'm sure theres somthing we could use, cheep too.
I have decided to get one of those halegen capsule bulbs and try it out 300watt 240v no balest needed
http://www.ecwuk.com/disco_lighting/lamps/
my projector at the moment is 20" long 13" wide and 16"high
at its highest point
I'm using an ask impack 24 panel,wich has an 8 1/2 inch lcd
I still need to get a decent lense.
anyone in the uk know of a good place for lenses
I think that prjctr_builder meant "rear" projection screens, woneill.
BTW, I have been brainstorming lighting ideas, and we have 2 headlights in our garage that were supposed to go on a 1984 Buick La Sabre. Since we don't have that car anymore, they're open for use. They're both halogen, but I'm not sure of the wattage. I figure they already have the reflectors built in, so that's done, and they're behind glass, so heat won't be a problem. There are two problems though: 1. They rely on DC voltage, and 2. There are three prongs that come out the back. I'm not sure which 2 I would need to connect to power the light. Also, I have an old computer power supply that has a 12V line with 6 amps of power. Would this be enough to power 2 headlights?
BTW, I have been brainstorming lighting ideas, and we have 2 headlights in our garage that were supposed to go on a 1984 Buick La Sabre. Since we don't have that car anymore, they're open for use. They're both halogen, but I'm not sure of the wattage. I figure they already have the reflectors built in, so that's done, and they're behind glass, so heat won't be a problem. There are two problems though: 1. They rely on DC voltage, and 2. There are three prongs that come out the back. I'm not sure which 2 I would need to connect to power the light. Also, I have an old computer power supply that has a 12V line with 6 amps of power. Would this be enough to power 2 headlights?
whelp, I just got through measuring focal distances of my fresnel, and, seems as though my light source was about 3" too close to it. It doesnt look like it would have made a HUGE difference, but, there is definitely something there. I'm going to remount the LCD panel and fresnel, (from about 9.5" to 12.5" from the light source) and see what happens. This will take a little work though, so, I probably wont have time until this weekend..
car headlights
my first attempt was with car headlights. not bright enough and color temp is too low. i tried using the new bulbs with the higher temp, but they are even less bright. this was a 6054 type bulb, probably the same as yours. i'm using ENX bulbs presently, and thaey are pretty easy to work with(small). the FXL bulb fits the same socket and has higher output but is significantly more expensive. i got my OHP for $50 and am using it as a learning tool. i suggest everyone who hasn't got one to get one. check out your local classified ads. there's plenty on eBay, but the shipping tends to make it not worthwhile. $.02
my first attempt was with car headlights. not bright enough and color temp is too low. i tried using the new bulbs with the higher temp, but they are even less bright. this was a 6054 type bulb, probably the same as yours. i'm using ENX bulbs presently, and thaey are pretty easy to work with(small). the FXL bulb fits the same socket and has higher output but is significantly more expensive. i got my OHP for $50 and am using it as a learning tool. i suggest everyone who hasn't got one to get one. check out your local classified ads. there's plenty on eBay, but the shipping tends to make it not worthwhile. $.02
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