The invention relates to an electronic system for implementing an optimized way to provide information from a first electronic device to a second portable electronic device, and to a method of implementing a virtual noticeboard. Here, in the optical member, there is a plurality of pairs of the reflecting surfaces or prism sections arranged in the direction perpendicular to the optical axis within a plane including the radial direction of the light source centered on the optical axis. The IO window has a fixing slot and a first screw hole. A golf ball whose cover layer has a very thin and uniform thickness as well as an improved outer appearance is manufactured. A portion of the second lead finger forms a bottom terminal lead structure.