| 摘要 |
PROBLEM TO BE SOLVED: To mount electronic parts to both surfaces on front and rear side of a circuit board, by using a circuit board with through holes. SOLUTION: The conductive patterns formed on the upper and lower surfaces of a substrate 14 are connected with each other through a through hole electrode 12a of a through hole 12. An electrode for external connection is formed on the side surface of the substrate 14, and at least a light emitting element 3 and a light receiving element 4 among electronic parts such as light emitting element 3, light receiving element 4, IC chip, capacitor, etc., are mounted to the upper surface of the substrate 14 and the other parts are mounted to the lower surface thereof, and then the upper surface of the light emitting element 3 and the light receiving element 4 on the upper surface side is packaged with a light-transmissive resin so as to be covered with a semi-spherical lens parts 6a and 6b and the electronic parts on the lower surface side are fixed by soldering. Further, the entire surface other than the lens parts 6a and 6b and the electrode surface of external connection are covered with a shield case so as to prevent an influence of external noises. Since double-surface mounting can be realized, a module can be made extremely compact. In addition, mass- production can be also realized, thereby reducing manufacturing cost. |
