Well, your screen looks like a regular projector screen rather than a backlit TV, so I'd have a projection spotlight in the projector itself (add a little volumetric to add to the effect). Then, if you need the screen to emit a little luminosity itself (to simulate the reflected/bounced light) then either add a dim area light or simply give a little luminosity to the screen...
(perhaps .. then again, I could be talking out of my Harris....
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