Keyswitch device, keyboard, and membrane circuit board

A keyboard, comprising:

• a base plate;
• a membrane circuit board disposed on the base plate, the membrane circuit board comprising:
• a reflective film layer located on the base plate;
• a transmissive film layer located over the reflective film layer;
• a light guide spacer film layer having a plurality of accommodating spaces, wherein the reflective film layer and the transmissive film layer are respectively located at opposite sides of the light guide spacer film layer;
• and
• a power supply circuit;
• a plurality of light sources sandwiched between the reflective film layer and the transmissive film layer, respectively located in the accommodating spaces, and spaced apart from the base plate, wherein the light sources are powered by the power supply circuit;
• and
• a plurality of keyswitch assemblies disposed on the membrane circuit board.

A membrane circuit board, comprising:

• a reflective film layer;
• a transmissive film layer located over the reflective film layer;
• a light guide spacer film layer having an accommodating space, wherein the reflective film layer and the transmissive film layer are respectively located at opposite sides of the light guide spacer film layer;
• a power supply circuit:
• and
• a light source sandwiched between the reflective film layer and the transmissive film layer and located in the accommodating space, wherein the light source is powered by the power supply circuit.