Patent ID: 8530768

Claim:
A thin illuminated keyboard, comprising: at least one keycap; and an upper light guide plate and a lower light guide plate that are located beneath the keycap and include respectively a first light guide layer and a second light guide layer opposing each other, the first light guide layer and the second light guide layer including respectively a first circuit layer and a second circuit layer laid on the opposing surfaces thereof and being interposed by at least one circuit switch corresponding to the keycap and triggered by depression of the keycap to generate a command signal, the first light guide layer and the second light guide layer also including respectively a first mask layer and a second reflection layer on the sides opposite to the first and second circuit layers; wherein the first mask layer and the second reflection layer form an optical passage therebetween, the first mask layer including at least one light penetration zone receiving light from the optical passage and project the light to the keycap at a preset location of the light penetration zone.