An abnormality diagnosis system 100 includes a VVT controller 110, an adjustable valve mechanism 120, a cam angle sensor 130, a model computation module 140, an abnormality detection module 150, and an alarm lamp 160. The reflecting portion reflects incident light from a counter substrate side toward the counter substrate, and the opening transmits incident light from the color filter substrate side toward the counter substrate. The at least one P-channel MOS FET and the at least one N-channel MOS FET are serially connected.