| 摘要 |
PURPOSE:To attain the use of a light emitting element of a low output by setting the spread angle of luminous flux radiated from a transmitter larger in a direction of the movement of a mobile station and smaller in a direction orthogonal thereto and setting a visual field angle of a receiver in matching therewith. CONSTITUTION:The spread angle of the luminous flux radiated from a transmitter 2 is set larger in a direction of the movement of a mobile station and to a required minimum angle in a direction orthogonal thereto. Moreover, the visual field angle of the receiver 5 is set in matching therewith. Thus, even a light emitting element 82 with a low output is used sufficiently and the range of establishment of a communication line is selected larger and number of transmitters to be installed is decreased. Thus, the inexpensive communication system is constituted. |
