A method of making a light active sheet. A bottom substrate having an
electrically conductive surface is provided. A hotmelt adhesive sheet is
provided. Light active semiconductor elements, such as LED die, are
embedded in the hotmelt adhesive sheet. The LED die each have a top
electrode and a bottom electrode. A top transparent substrate is provided
having a transparent conductive layer. The hotmelt adhesive sheet with
the embedded LED die is inserted between the electrically conductive
surface and the transparent conductive layer to form a lamination. The
lamination is run through a heated pressure roller system to melt the
hotmelt adhesive sheet and electrically insulate and bind the top
substrate to the bottom substrate. As the hotmelt sheet is softened, the
LED die breakthrough so that the top electrode comes into electrical
contact with the transparent conductive layer of the top substrate and
the bottom electrode comes into electrical contact with the electrically
conductive surface of the bottom substrate. Thus, the p and n sides of
each LED die are automatically connected to the top conductive layer and
the bottom conductive surface. Each LED die is encapsulated and secured
between the substrates in the flexible, hotmelt adhesive sheet layer. The
bottom substrate, the hotmelt adhesive (with the embedded LED die) and
the top substrate can be provided as rolls of material. The rolls are
brought together in a continuous roll fabrication process, resulting in a
flexible sheet of lighting material.