OPTICAL MODULE, OPTICAL TRANSMITTER/RECEIVER MODULE, PRINTED CIRCUIT BOARD, FLEXIBLE BOARD

PROBLEM TO BE SOLVED: To provide an optical module which reduces reflection or radiation at a connection point and reduces signal deterioration of an electric signal to be transmitted, an optical transmitter/receiver module, a printed circuit board and a flexible board.SOLUTION: The optical module includes: a first board including a first signaling terminal part and a first grounding terminal part which are formed on a front surface; and a second board including a second signaling terminal part and a second grounding terminal part which are formed on a rear surface. The first board further includes: a first dielectric layer; first signaling wiring that is formed on a front surface of the first dielectric layer; a first grounding conductor layer which is formed on a rear surface of the first dielectric layer; and a first penetration grounding conductor which penetrates the first dielectric layer from the rear surface to the front surface. The first grounding terminal part is formed in a first region and a second region which are positioned oppositely to each other while interposing the first signaling terminal part therebetween in a first direction in a planar view, and in a third region that is specified at a position over the first signaling terminal part in a second direction that is orthogonal to the first direction.SELECTED DRAWING: Figure 3A 【課題】接続箇所における反射や放射が軽減され、伝送する電気信号の信号劣化が低減される、光モジュール、光送受信モジュール、プリント基板及びフレキシブル基板の提供。【解決手段】表面に形成される第１信号端子部及び第１接地端子部、を備える第１基板と、裏面に形成される第２信号端子部及び第２接地端子部、を備える第２基板と、を備える、光モジュールであって、前記第１基板は、第１誘電体層と、前記第１誘電体層の表面に形成される第１信号配線と、前記第１誘電体層の裏面に形成される第１接地導体層と、前記第１誘電体層を裏面から表面へ貫通する第１貫通接地導体と、をさらに備え、前記第１接地端子部は、平面視して、第１の方向において前記第１信号端子部を挟んで互いに反対側に位置する第１領域及び第２領域、並びに、前記第１の方向に直交する第２の方向において前記第１信号端子部を越えた位置に規定される第３領域、に形成される。【選択図】図３Ａ