CurtPalme.com Home Theater Forum

[noos@xp37+]

Hey,

currently I am prototyping a massive dome/torus screen. As it is not possible to achieve vertical curve on a simple test screen, I only do horizontal curve and read vertical with a sheet of paper. I have to do this because I want to find out the specifics of a new lens-projector relation that I discovered. I use 8"LC lenses on a 9" CRT (9500 Ultra). The HD117s and HD114s bolt directly into the HD10 system - you will only need screws with a bigger head. The result is a short throw lens with ultra curve capabilities (but only this and only front projection). Throw is about 0.7:1 - so for every 0.7meter you get one meter on the screen.

My Ultra is a Tan (Helmut Tan), so he has the blackbox installed: http://www.curtpalme.com/forum/viewtopic.php?p=336742
The standard Ultra geometry allows to compensate a depth of a little more than 20 percent from the screen width (4 meters result in a 80cm deep screen). My HD10r5m lenses allows more curve (30%), and that geometry can be achieved with the blackbox switches plus 100% bottom pin. But running 8" LC lenses like HD117-12/24 will give you a curve of about 40% of screen width. HD114 resolve too bad, while HD117 are on par in the center with crisp HD10L (thanks barclay66) and seem sharper than the HD10r5m that you guys know from my 4k series.

My problems:
-I run the Ultra fully open, with a room fan directed on the tubes. That should also cool the open FGM segment, but it there anything else the could need extra cooling with this geometry?

-Biggest problem is that I am running out of bottom pin (100) for 40% curve, while top pin is only at 40. Beside options to manipulate a board (that are highly welcome), is there a setup manipulation to equalize top and bottom pin. I tilted the Ultra nose up and down, but no effect.

Thanks for reading

Marc-


...I want to add that I could do geometry via external processing or PC based, but I want the CRT to do it. No scaling, all input types, all resolutions and refreshrates !

[CasetheCorvetteman]

Looks interesting!!

[Francisco]

Hi Mark,

Why not try my MANAKIN.1 lenses? you have short throw and possibility for extreme curvation.
This is a setup with the manakin's http://www.youtube.com/watch?v=_B7rvj1GaAg

[noos@xp37+]

[mp20748]

There is no lens that will allow perfect focus/geometry on that curved screen. You would need 3 projectors even for that size screen, for which is what most small simulator screens also use.

You can however get away with using a special curved screen lens, but don't expect perfection in all zones and edges.


A typical single pilot cockpit simulator could have anywhere up to 6 projectors placing various images on the multi window display in front of the pilot. These types of flight simulators are more true to what you would see in the plane itself.

[garyfritz]

You're using a brown tweed carpet as your test screen !?!?

[Francisco]

[noos@xp37+]

Hello,

and thanks for your replies. I was able to reread the max curve for the HD10r5m curve/dome lenses and the unusual combo of 9" and 8" LC lenses. As tiny bit of geometry range is missing to run the hd117s at a 40% curve screen,
I was watching stuff for some dozen hours on the H10r5m. With their normal throw I only had a 3.5 meter wide picture and a 30% plus curve (1,15 meter deep screen) - from about 1,15 meter seating distance. Wow, the eyes are perfectly comfortable that close, as they have not to refocus across the horizontal center line of the screen(on a two axis dome/torus every point on the screen will be in equal distance to the eyes). Full field of view coverage plus head movment needed to get all of it. Fight Club - in the scene were they sit in the car and they learn to let go - you sit in the backseat with the camera! When you do 3d, you become surrounded by 3d objects.
Because of massive pleasure I started to prototype version two, with more pillars - and they will be connected with a curved plastic structure...
But I will post pictures when done. Also will the "dirt white" carpet (brown with low room lights) receive a high reflective white coating at the final curvature. This curvature will be tested for some time, before a full vacuum controlled 4,8 meter two axis torus /dome screen will be set up - 2 meters deep thanks to Hd117 on 9" ( if the last geometry issue is/can be solved)

I will also redo my test series of curve lenses and normal ones. My Hd134 are sold, but only had excellent flat and little curve capabilities. Hd10r5m is covered now. I will also test special AC curve lenses and post pictures of these huge pure metal/glass beasts (nowhere plastic!). I will also include Hd144 and Hd145, as they showed very good results on my last tests (20% curve). Some Hd10 and Hd8 stuff too....
Francisco, if you send me one of the scratched Mankins, I can include them and send it back to you.

[noos@xp37+]

Ok, second test screen is evolving. By lifing the nose of the Ultra very much up, my bottom pin is close to sufficent now. But I am not running the max curve of the Hd117, and my menu of bottem pin is at 100%. And most importantly by raising the nose of the ceiling mounted CRT, I can not project to the lower part of the screen. If I shift the picture via porches on the tube so that it fits the lower part of the screen - the corners of the hexagonal curved tube face pattern run out of tube face. So if there is no other way to increase bottom pin than by lifting the projector nose, I have to mount the Ultra half a meter deeper, with the accepable side effect of me sitting a bit more in the path of light and covering it.

Some posts that might help or not, opinions wanted if these could work on my Ultra:

https://www.curtpalme.com/forum_archived/viewtopic.php@t=30199.html (also @ Curt Palme if he still has those or does remember something)

last post here from tse sounds helpful but beyond my capabilities:

http://www.curtpalme.com/forum/viewtopic.php?p=336742


barclay66 are you alive? This should be a walk in the park for you...

[barclay66]

[noos@xp37+]

Hey Barclay66,


Norway? Civil or for a projector?
I am not in hurry and as you know it takes weeks for me to meet someone. But I think if your busy time is over, it would be time for a visit at my place.

Peace

John Wayne

[barclay66]

[noos@xp37+]

Gute Fahrt!

[tse]

[noos@xp37+]

Scott,


thank you so much - even I have doubts I will get one of those in my natural life span. But I will try try try try try try try try try!


Does it also mean a 9520 is in general optimized for curve, or was it the base for the curve prototype.


Wow, that is what I like most about CRTs. I think your pictures a porn for us Marquee/CRT addicts!!!!!!

Thanks


Marc

[noos@xp37+]

Short update:

The HD117/114 are off table because thei screen with 9" tubes is more triangular than curved.

I use the HD10r5m - great great curve lenses - at about 30% deepth from the screen width. Wow...
The projector is for tests now in the 0-axis position - as he can handle the geometry then. Wow, but not enough...

The biggest problem: The screen paint
Yes, the contrast is ruined at this deep curve, as the left screen side is directly facing the right side. So I use grey for the sceen to get back better contrast, But I still do testing. Brightness is still insane, because of the strong curve. Will do tests with dark rear-projection materials....

[Nashou66]

Your nuts!!!!

In a good way!!!

Nashou