See also V2 here https://makerworld.com/en/models/222069 for a slightly different design.
Low profile glass top LED riser with integrated stand for ventilation and reflector to focus the light inside the printer and reduce the light leakage out of the printer. Uses standard 10mm LED strip, approx 135 cm / 53 inches long. Uses a TPU liner for soft dampening of the glass top. Efficient design minimizes filament waste and easy print. Fits both X1 and P1 series of printers.
Use a white or silver plastics for the reflector.
See the effect of the LED light with and without reflector (using White matte PLA):