Fingerprint image sensor and method for optical wireless communications using the same

The present disclosure provides a fingerprint image sensor and a method for optical wireless communications using the same. The fingerprint image sensor includes: a backlight plate; an image sensor unit, disposed above the backlight plate; and a protection layer, disposed above the image sensor substrate; wherein the fingerprint image sensor is configured to operate at least in a transmitting mode and a receiving mode, where in the transmitting mode, the backlight plate is turned on and configured to emit lights with different optical characteristics representing coded information, and in the receiving mode, the backlight plate is turned off and the image sensor unit senses external lights and convert the external lights to electric signals. The present disclosure further provides methods for transmitting and receiving information using the fingerprint image sensor. Accordingly, the fingerprint image sensor can work as a transceiver to realize optical wireless communications.