Vintage Night Light

I stumbled upon this vintage night light and what caught my eye was how uniformly the light area was lit. Also the eery green colour looked unusual. Knowing that most of the time glow lamps are used, it was very unlikely that they could spread the light so well to produce this even output.

With some old electronics pliers I carefully lifted the rivet. It were these screw-like rivets. Awesome, this way I wouldn't destroy anything. Looking inside it became apparent that my assumption was correct: They used an electroluminescent surface. This is basically two conductive layers and the light emitting material in between. Here the base material is a metal plate with one lead connected. Ontop of it some kind of emaille. And then some probably invisible area of some conducting material where the other lead is attached to. As shown in the pictures not the whole area is emitting light, but only where the conducting coat is applied on top. A quick google search yields that similar night lights can still be bought. There is no date on the light but from the box design I didn't expect this technique being used in cheap consumer products from that time.