Membrane keyboards with surface mounted light-emitting diodes

Front panel of such keyboard can be flat or shaped. Super thin light-emitted diodes are directly mounted on flexible printed circuit boards by applying thick paste on conductive membrane. Visible corner of light-emitting diode's luminescence increase at forming of front panel at the place of light-emitting diodes location, i.e. lens effect emerges.Luminescence contrast of light-emitting diodes increase, if lens on light-emitting diode is covered by color polish, which spectrum will close by length to the length of luminescence of light-emitting diode.