Optical keyswitch comprising a keycap having a light transmission area and a keycap projection area projected on a circuit board

An optical keyswitch, comprising:

• a switch module, comprising a circuit board, an emitter, and a receiver, wherein the circuit board includes a first surface and a second surface, the emitter and the receiver are electrically connected to the circuit board, and the emitter is configured to emit an optical signal to the receiver;
• a keycap, disposed above the first surface, wherein the keycap includes a light transmission area, and a keycap projection area of the keycap is projected on the circuit board;
• a support mechanism disposed below the keycap and configured to support the keycap moving upward and downward with respect to the circuit board;
• a resilient member transversely connecting the support mechanism, and dividing the keycap projection area into a first region and a second region;
• and
• a protrusion driven by the keycap or the support mechanism to move upward and downward;
• and
• a backlight source electrically connected to the circuit board;
• wherein the backlight source is disposed at the first region to produce light illuminating the light transmission area, the emitter and the receiver are disposed at the second region, and the protrusion is moved by the keycap or the support mechanism to trigger the switch module.