US Patent 7758226 Billboard and fabrication thereof

An exemplary billboard includes a backlight module, a light transmissive canvas, a pattern layer and a light converging layer. The light transmissive canvas is adjacent to the backlight module. The light transmissive canvas includes a first surface facing the backlight module and a second surface opposite to the first surface. The pattern layer is formed on the second surface. The light converging layer covers the pattern layer and comprises a plurality of microstructures formed thereon distal from the light transmissive canvas.