Emerson 609 projection TV

[old_tv_nut]

The 45 degrees in all directions is the kind of thing you would expect from the circular pattern. Not sure what the horizontal lines are doing in your case.

Modern rear projectors (CRT and DLP) used very strong tiny horizontal prisms to get the light hitting the screen at a steep angle bent to horizontal and out the front. In the very shallow cabinet DLP sets, the horizontal prisms actually produced total internal reflection, so light entered from the bottom of the prisms, reflected backwards off the top, and then reflected off the back of the prisms, forward and out.

Modern screens typically also had vertical or circular fresnel elements on the opposite side to get the kind of directivity you are seeing, but it often was stronger in the vertical direction than the horizontal.

[Phil Nelson]

Originally Posted by old_tv_nut

Not sure what the horizontal lines are doing in your case.

In an ARF discussion of this screen, it was suggested that the horizontal lines were a cheap way to make the panel translucent, and they might also slightly defocus the CRT's horizontal scan pattern.

Regards,

Phil Nelson
Phil's Old Radios
https://antiqueradio.org/index.html