| 摘要 |
PROBLEM TO BE SOLVED: To enhance the transmission efficiency of signal light and to decrease the variations in the exit light at the end edge on a side where the signal light is emitted, by diffusing the signal light by using cylindrical lenses arrayed with plural cylindrical surfaces in the longitudinal direction at the end edge on the side where the signal light is made incident. SOLUTION: A signal light 200 made incident on the signal light incident part of an optical data bus 100 is first refracted by the second cylindrical lenses 121 and is further refracted by the first cylindrical lenses 111, by which the signal light is once focused, then diffused. The diffused signal light 210 passes the inside of the light transmission part and is propagated to a signal light exit part 140. The spreading of the diffused signal light is determined by the ratio of the combined focal length f' and pitch p of the first and second cylindrical lenses 111, 121. Respective parameters are so set as to satisfy the relation f'<p.L<D when the transmission distance of the light transmission is defined as L and the width of the signal light emission part as D, thereby, broadcasting characteristic is satisfied. |
