I need recommendations for 1080p projectors with no more than a meter throw for a 70-inch image--distortion free as it will be viewed up close. I'm working on a custom rear-projection system that has several touchscreens on various sides of a small enclosure. Basically, I need to fit 3 (or 4) projectors in an column with horizontal cross-section being an equilateral triangle (or square) that is just over 4 feet per horizontal side, and each side has a 70" screen in portrait orientation. I can't use LCDs/plasmas due to the power requirements, and interference with some of the touchscreen technologies I'm considering which need to see the rear of the projection screen with an infrared camera.

The problem is that the 1080 projectors that have short throw lenses available are all very expensive and very bright;...too bright for a 70" screen.

Better buy a Mitsubishi 73" DLP and use that.

PS If you have limited power available, you could use the 67" diagonal Samsung HL67A750, which has a LED light source instead of a bulb and uses allot less power.

IB

I see one only 17.5" depth which might work. I'll still have to take off the shell and mount everything to a rigid frame, so I'd essentially be scavenging the TVs for their major components.
Can these be turned on the side? I need portrait mode. One Sony we looked at, we were told we could not have it on its side.
One problem I'm having is that all these are designed to have the projector offset from one of the long sides of the display area. However, I need to put it on one of the short sides as else it will interfere with the beam projecting onto the neighboring screen... I do also have some concern about using a projection TV's screen since I don't know how if it affect the touchscreen imaging of the infrared camera.
Basically I have to fit four screens in the following sort of thing, (and also the touch imaging stuff and four computers): http://i35.tinypic.com/ak7ho2.png Ditto for a triangular version.

1 meter = 3.3 feet.
3.3' = 39"
70"/39"=1.79x

Does that look correct? This is assuming a 70" wide, not diagonal. If this is correct...there are actually a lot of options.

Unless I missed something...

1 meter = 3.3 feet.
3.3' = 39"
70"/39"=1.79x

Does that look correct? This is assuming a 70" wide, not diagonal. If this is correct...there are actually a lot of options.

Unless I missed something...

Its the other way around, 39"/70" = 0.557x.

Screen diagonal is 70 inches, portrait orientation. Enclosure is a bit over 4 feet per horizontal side, 6.8 to 7 feet tall.

Whoops. You are correct. Well then he is SOL. :) Seriously, not much out there.

Nixie, do you have a drawing or CAD model for the system. I'm having a hard time visualizing what you are trying to do.

Strange, I didn't get an email notification that there was a reply...

The CAD guy isn't done but I'll scan a better hand drawing later today.

By the way, how is the shift done in projector systems to have the image off-axis? Is it a simple lens shift? If so, shouldn't it be possible for me just to rearrange the lens relative to the display to get a shift in a different direction? I certainly don't mind if I have to take apart a projector and mount things in a different frame.

Uh, I would be looking at commercial cube systems probably, dunno what solutions are out there for that, but bound to be very short throw.

While not practical in many situations, you could use a mirror in the back of the room to effectively lengthen your throw.

The CAD guy isn't done but I'll scan a better hand drawing later today.

By the way, how is the shift done in projector systems to have the image off-axis? Is it a simple lens shift? If so, shouldn't it be possible for me just to rearrange the lens relative to the display to get a shift in a different direction? I certainly don't mind if I have to take apart a projector and mount things in a different frame.

Thanks, any sort of a drawing would be helpful.

Yes, shifting the lens will move the image. Most consumer level 1080 projectors will have horizontal and vertical lens shift. One thing I've found is that the lens mount on these projectors is flimsy plastic and can't be guaranteed to hold position . I've milled my own lens mount out of aluminum and it works pretty well. It's not as easy to adjust, but will lock down tight when you get the lens where you want it. If you go this route, you'll want to experiment with different projector models to see how easy it is to get to the lens. On some you just have to take off the case, but on others you have to practically disassemble the whole thing. If you're just doing a couple, it's not that big a deal, but if you're doing 50+ the extra time adds up.

Albert

Well the issue is not just shift, but shift without distorting it.

Here's a sketch. Since the touchscreen method might be infrared imaging of the backsides of the screens by a camera, I can't have the projectors or mirrors stuff block the screens. Some of the space is also taken up by computers, the internal frame, etc.

http://i33.tinypic.com/2drri21.png

Lens shift doesn't distort the image as long as you don't go too far. We build video walls among other things and haven't had any problems with distortion due to lens shift.

Hmm... I don't think you're going to be able to do this with projectors. Since you want 3 or 4 faces with screens, the throw distance plus the depth of the projector would have to fit in half of 4.5'. With a direct throw and the smallest screen size (57" wide, 65" diag), you'd only have about 15" from the front of the projector to the screen. I've never seen a 0.26:1 lens. The best you could hope for would be about 0.8:1.

Are you sure you can't use a big LCD or plasma? A 57" LCD uses about the same amount of power as a projector. You could use a SmartTech overlay and make your life a lot simpler. It's my understanding that they are capable of multi-touch, but you need to dig into the code.

Albert

There is a new touch screen technology I saw that uses a thin over lay to make any flat panel a touch screen. Not sure where to find it.

Nate

Lens shift doesn't distort the image as long as you don't go too far. We build video walls among other things and haven't had any problems with distortion due to lens shift.

Hmm... I don't think you're going to be able to do this with projectors. Since you want 3 or 4 faces with screens, the throw distance plus the depth of the projector would have to fit in half of 4.5'. With a direct throw and the smallest screen size (57" wide, 65" diag), you'd only have about 15" from the front of the projector to the screen. I've never seen a 0.26:1 lens. The best you could hope for would be about 0.8:1.

Are you sure you can't use a big LCD or plasma? A 57" LCD uses about the same amount of power as a projector. You could use a SmartTech overlay and make your life a lot simpler. It's my understanding that they are capable of multi-touch, but you need to dig into the code.

Albert
LCDs and plasmas have about three percent efficiency. A projector that would give the same brightness on the same display area uses around a third of the power.
65" LCDs and plasmas are over 600 W. A rear projection TV with the same size and brightness is a fraction of the wattage.
So one of the issues is finding a small HD projector designed for a screen size not much over 70".
I wouldn't mind ripping out the projection system from projection TVs, except that they use mirrors instead of lens shift and are not designed for adjustability.

I looked at the site for the overlay and it seems to be an actual surface put onto the display. Since the unit needs to be vandal proof, I'm putting lexan or borosilicate windows over the screens and so cannot use a technology requiring direct contact.
I'm looking at the laser or infrared frames but they don't seem to do multitouch.

If the projectors can be offset towards the sides and/or corners, they should be able to be put back quite a bit further than the midpoint, maybe even three feet. So I'm looking for HD projectors suitable for a 70" display area from a throw no more than a meter.

can anyone recommend a 1080p Short Throw, to get a 100" screen from about an 11ft throw or so?

can anyone recommend a 1080p Short Throw, to get a 100" screen from about an 11ft throw or so?

I have that with my AX200 and will have it again when I upgrade to the AE3000. The Sanyo will do it as well. Even the Epsons. Not that hard.

I have that with my AX200 and will have it again when I upgrade to the AE3000. The Sanyo will do it as well. Even the Epsons. Not that hard.

really? I looked at those on the Projector Central image Calculator thing and it says they won't do that, or it was out side the 'green' area of being ideal for it I guess? I'd love to have the Panny


How is the image? My Sharp looks great for the price but I'm having trouble with it syncing with my ps3. If I make a move, I either need to find an older, high-end 720p or go 1080p, wish they'd fall in price again

can anyone recommend a 1080p Short Throw, to get a 100" screen from about an 11ft throw or so?

Well, my dVision 1080p throws an outstanding picture with it's short throw lens. In fact, we watch a 118" wide 128" diagonal 2.35:1 picture ( no anamorphic lens ) with the projector only 14' from the screen.

I can't find the HL67A750 anywhere in Vancouver (Canada) :(

really? I looked at those on the Projector Central image Calculator thing and it says they won't do that, or it was out side the 'green' area of being ideal for it I guess? I'd love to have the Panny


How is the image? My Sharp looks great for the price but I'm having trouble with it syncing with my ps3. If I make a move, I either need to find an older, high-end 720p or go 1080p, wish they'd fall in price again

I don't pay attention to the green on the calculator. You can always tone down the brightness. Anyway the image is amazing! Just for grins I put my EZ cinema portable screen in front of my projector at full zoom. It filled a 84" diaginal screen at 8ft 1 inch from screen to lens. I watched Gladiator from my DVR (1080i) and loved it! I have a Ps3 and haven't noticed any problems with sync.

Samsung doesn't have HL67A750 left, and they're not making any more :(
We need at the very least 20 screens within two months, better around 100 to 400 from the beginning so we able to do a deal with a leasing company.
Just when we thought we had found something...
What else can I use that also has a very short depth?

Hi Nixie,

PM me as we make 1080p engines for video wall applications.

Thanks,