JPH05335617

PURPOSE:To obtain an optical transmission module in which a transmission and light reception circuits are integrally modulated by integrally molding a light receiving and emitting elements and a double-sided substrate in a sealed state. CONSTITUTION:A molded part 402 to which a sealed case 407 is fixed, circuit board 401 mounted with lead terminals 404, and case 405 are combined and a light receiving element module 202 is soldered to a circuit board 401. In addition, a light emitting element module is fitted to the board 401 through a flexible substrate 410. Then a sealed case 411 is fitted to the case 407 so as to cover the lead terminals of a preamplifier and the module 202 and the case 411 is completely sealed so as to shield radiation noise. In addition, the cut and raised part of the case 405 is bent and soldered to the case 411. Therefore, when a molded part 403, substrate retainer 408, and case 409 are fitted and fixed with spiral screws 406, an optical transmission module which is suitable for high-density integration and can reduce signal leakage can be obtained.