Dear Mehdi ,

i have had seen this project sometimes ago ,so got the idea and i'm in the process of designing one for myself , nice to see a disscution on it here ,i was in doubt which controller to use (MCS51/AVR),but currently i'm working on AT89S51 Along it , i'll let people here know of the result(along pictures and movies).

here is some explanation on this type of displays :

as you can see in this picture :(all the pictures are drawed to view the object from the side)

this is the scheme which Bob Blick http://www.bobblick.com/techref/projects/propclock/propclock.html (Not Click !) used,it leads to an Cylindrical display .


looking at this picture :

we can easily upgrade our propeller to a Sphere display by converting our propller shape into a half circle. so what ? now you have a sphere and you can display everything on every side of it , you can turn around it and see diffrent things from each side !
kinda intresting it gets ...

also look at this picture :

if i were right i've seen this somewhere on the net (have to look for the address and will let you know) the guy displayed a REAL 3D DNA on it , you could see the diffrent sides of the DNA by looking around and looking from top and down as it was a REAL object in the sphere !.

as i think it should be somehow applyable to a LED display, of course it gave lower resolution in the horizontal section but the resolution on the vertical axis is based on the processing power of the MCU.

the benefits of this type of display in my mind is that you get an unlimited (virtualy) resolution on the vertical side , and if you use SMD RGB LEDs then a neat display is produced. thats really easy to build rather than building a Matrix one.as Bob says it's a 'mechanichally scaned' display.
even building the REAL 3D display shouldn't be hard , as LCDs are available in small packages in example the ones that are being used in HandyCams viewfinders. but here i doub't that the image processing could be done even using powerfull 8051 derivatives.

Best Regards :
Farshid J.H.