US Patent 10276327 Luminous keyboard and luminous keyswitch thereof

A luminous keyswitch includes a keycap having a light-transparent portion, a baseplate, an up-down mechanism with two ends respectively moveably connected to the keycap and the baseplate, a function sheet disposed on or under the baseplate, and a light source disposed on the function sheet within a vertical projection of the keycap and connected by a copper wire to provide a light illuminating the light-transparent portion. The function sheet includes a flexible upper circuit layer having a first contact point, a flexible spacer layer having a hole, and a flexible lower circuit layer having a second copper contact point, a third copper contact point, a first copper wire connected to the second copper contact point, and a second copper wire connected to the third copper contact point. When the keycap is pressed, the first contact point passes through the hole to electrically connect the second and third copper contact points.