CRT displays [was: computer graphics in the 1950s]
cc at informatik.uni-stuttgart.de
Sat Oct 25 07:11:55 CDT 2008
On Fri, 24 Oct 2008, der Mouse wrote:
>> I just want to mention that there were polar-coordinate tubes.
> Wow. I can't even imagine how I'd build a deflection system that
> worked in polar coordinates. Do you happen to know anything about how
> the deflection worked?
I've never seen such a tube in any equipment myself, but there is a very
interesting (German) discussion on the RCA 3DP1 polar-coordinate tube:
Nonetheless I recommend having a look at this link as there are great
pictures from the tube including pinout, data and photos from a
This particular tube has four deflection plates as in an ordinary
electrostatically deflected tube. You apply a sine/cosine voltage to the
plates to create a circle. But additionally there's a needle at the center
of the screen used for the polar deflection.
Maybe there is more information in the patents 2328259 (Polar
coordinate cathode-ray tube, 1943) and 2864033 (Polar coordinate tube,
1958), both found on freepatentsonline.com, but the site seems to be
non-functional at the moment.
More information about the cctalk