NOVELTY - Mount assembly includes greater than or equal to2 photoelectric conversion devices, in which the photoelectric conversion device(s) is a device for converting a light signal to an electrical signal and the other is a device for converting an electrical signal to a light signal. It is a spherical photoelectric conversion device having a photoelectric conversion portion formed on a surface of a spherical semiconductor material.    USE - The mount assembly is used in optical transmission line useful for photoelectric circuit board. It emits a light signal corresponding to an incident light signal. (All claimed) It is also used as optical relay module for high speed and high-capacity data communication.    ADVANTAGE - The inventive mount assembly is capable of optically connecting greater than or equal to2 optical transmission lines efficiently.    DETAILED DESCRIPTION - Mount assembly (100) comprises greater than or equal to2 photoelectric conversion devices, and spherical semiconductor device(s) (12a, 12b) which forms an electronic circuit. The photoelectric conversion device(s) is a device for converting a light signal to an electrical signal and the other is a device for converting an electrical signal to a light signal. It is a spherical photoelectric conversion device having a photoelectric conversion portion formed on a surface of a spherical semiconductor material. The spherical semiconductor device(s) is disposed between the device for converting the light signal to the electrical signal and the device for converting the electrical signal to the light signal. The devices are electrically connected. INDEPENDENT CLAIMS are also included for:    (1) optical transmission line comprising a core layer, a clad layer, and the mount assembly disposed within the core layer;    (2) multilayer optical transmission line comprising greater than or equal to2 layers, each of which has an optical transmission line comprising the mount assembly disposed across the core and clad layers and divides or change the optical transmission line of one layer to the optical transmission line of another layer; and    (3) photoelectric circuit board comprising an optical transmission line having the clad layer and the core layer where the mount assembly is disposed.    DESCRIPTION OF DRAWING(S) - The figure shows a side view of a mount assembly.    Spherical semiconductor devices (12a, 12b)    Electrical-connection portion (14)    Transparent resin (16)    Mount assembly (100)