Patent ID: 7885547

Claim:
An optical space transmission system comprising an optical transmitter and a terminal, wherein the optical transmitter transmits data from the optical transmitter to the terminal by means of optical space transmission using a beam of a wavelength of an infrared light region, wherein the terminal comprises: a visible light transmission section operable to emit a beam of a wavelength of a visible light region; and a first light reception section operable to receive the beam of the wavelength of the infrared light region, and wherein the optical transmitter comprises: an incident beam restriction section operable to transmit the beam of the wavelength of the visible light region emitted by the terminal only if the terminal is located within a range in which the beam of the wavelength of the infrared light region emitted by the optical transmitter would be incident upon the terminal; a reflection section operable to reflect the beam of the wavelength of the visible light region transmitted by the incident beam restriction section; a second light reception section operable to receive a data transmission request signal from the terminal; and a light source operable to emit the beam of the wavelength of the infrared light region to pass through the reflection section after the second light reception section receives the data transmission request signal.