Prisms

[DJZ]

This is an old school way of doing color modulation. Just to the left is a set of scanners, one to move the beam to the side so that it gets blocked after the prisms and before the X/Y scanners (blanking), the other scanner is to sweep the beam up and down on the prism (color modulation). Just to the right is the set of X/Y scanners. Part of an old projector I want to restore one of these days. Thought you guys might enjoy the beam shot!

 

[Speedy78]

So one scanner is for blanking, one for color selection and then the X/Y set?

 

[DJZ]

Yes. This was before PCAOMs! And was a very creative way of modulating color. In all this old projector has 3 scan heads and 2 color mod/blanking paths.

 

[Speedy78]

Need to get that thing up and running.

 

[DJZ]

Need to get that thing up and running.

I agree completely! Needs a lot of work though. I also need to get rid of my air cooled ion and replace it with a water cooled. During the summer my office AC just can't keep up during the day.

Here's a shot from another angle, at the very top sorta to the left of center, what looks like a green dot is actually yellow, just to the right of that is red. Those 2 colors would make it to the scan heads if the shutters were open. As the beam is swept up and down on the prisms a different color reaches the scan heads.

 

[Cyparagon]

Are the colors ever re-combined?

 

[KapHn8d]

I don't fully understand what's happening in the pic, but it's an awesome image! Thanks for sharing!

cheers!