Patent ID: 8207462

Claim:
A key structure having an improved light emitting efficiency, comprising: a light guide plate having a top surface and a bottom surface, wherein a circuit and a plurality of first electrical contacts are distributed on a top surface of the light guide plate, an optical structure is disposed at a bottom surface of the light guide plate, and a light source is provided at a lateral side of the light guide plate; an isolation sheet, disposed on the light guide plate and configured with a plurality of through holes positionally corresponding to the first electrical contacts; a circuit board, disposed on the isolation sheet, wherein a plurality of second electrical contacts are disposed at a bottom surface of the circuit board positionally corresponding to the through holes and the first electrical contacts; an elastic member disposed on the circuit board; and a key cap disposed on the elastic member, wherein the light source emits a light into the light guide plate; the isolation sheet has a light reflective surface facing the light guide plate, and the light reflective surface is adapted for reflecting a light outputted from the light guide plate back to the light guide plate, and the light is then reflected by the optical structure to pass through the through holes and the circuit board, so as to output from the key cap.