[GeoffR]

My guess it that it would look terrible, without a light-guide layer the lighting would be so uneven it would be a real distraction to reading. I think you would get much better results from a clip-on light.

Edit: And without a light-guide-layer to direct the light down on to the screen it would really be more of a sidelight than a frontlight, and every bit of dust on the screen would cast a shadow.