An optical detector, comprising: a stacked structure including a first electrode, a photoelectric conversion layer, a second electrode, a first insulating layer, and a third electrode; an active layer (6, 6') electrically coupled to one of the first electrode or the second electrode, and electrically coupled to the third electrode; a gate insulating layer (7, 7') on the active layer (6, 6'); and a gate electrode (8, 8') on the gate insulating layer (7, 7'), wherein: the optical detector further comprises a second insulating layer arranged between the active layer and the photoelectric conversion layer, and between the active layer and the second electrode; the active layer is electrically coupled to the first electrode and is electrically insulated from the second electrode; the second insulating layer is arranged on a side wall of the photoelectric conversion layer and a sidewall of the second electrode; and the active layer is formed on an edge region of an upper surface of the first electrode, the second insulating layer, and the third electrode; or, wherein: the active layer is electrically coupled to the second electrode and is electrically insulated from the first electrode; and the active layer is formed on a sidewall of the second electrode, a sidewall of the first insulating layer, and the third electrode. a stacked structure including a first electrode, a photoelectric conversion layer, a second electrode, a first insulating layer, and a third electrode; an active layer (6, 6') electrically coupled to one of the first electrode or the second electrode, and electrically coupled to the third electrode; a gate insulating layer (7, 7') on the active layer (6, 6'); and a gate electrode (8, 8') on the gate insulating layer (7, 7'), wherein: the optical detector further comprises a second insulating layer arranged between the active layer and the photoelectric conversion layer, and between the active layer and the second electrode; the active layer is electrically coupled to the first electrode and is electrically insulated from the second electrode; the second insulating layer is arranged on a side wall of the photoelectric conversion layer and a sidewall of the second electrode; and the active layer is formed on an edge region of an upper surface of the first electrode, the second insulating layer, and the third electrode; or, wherein: the optical detector further comprises a second insulating layer arranged between the active layer and the photoelectric conversion layer, and between the active layer and the second electrode; the active layer is electrically coupled to the first electrode and is electrically insulated from the second electrode; the second insulating layer is arranged on a side wall of the photoelectric conversion layer and a sidewall of the second electrode; and the active layer is formed on an edge region of an upper surface of the first electrode, the second insulating layer, and the third electrode; or, wherein: the active layer is electrically coupled to the second electrode and is electrically insulated from the first electrode; and the active layer is formed on a sidewall of the second electrode, a sidewall of the first insulating layer, and the third electrode.