Gkdantes has the right idea.

Put in your screen with the glow just like you have but without anything glows.

Then, put in a spot light behind the screen with an angle that you like.  Make the screen to not cast a shadow and set things up so the screen won't receive the light.

Then set the range falloff and angle falloff to 100% and adjust the distance appropriately.

It's a little bit of work but it can get you what you want.

The two render option is also fine.

Let us know how it works out.

-Kix