Endoscope apparatus

An endoscope apparatus configured for use in a potentially explosive environment, the endoscope apparatus comprising:

• a scope unit including a control unit;
• an image pickup element disposed at a tip of the scope unit;
• an insertion portion connected to the control unit;
• a main unit connected to the scope unit and the control unit;
• a barrier circuit disposed in the scope unit which includes a zener diode connected to ground and configured to limit energy applied to a circuit, to an extent sufficient to eliminate the energy as a factor in causing explosion in said potentially explosive environment, and
• an image pickup element drive board disposed in the scope unit so and configured to produce various pulses for driving the image pick up element and to produce a power supply,
• wherein the barrier circuit is configured to pass an output signal to the image pickup element and an input signal from the image pickup element, the barrier circuit is further configured to limit an output signal from the image pickup element drive board, to an extent sufficient to eliminate the output signal as a factor in causing explosion in said potentially explosive environment, and the barrier circuit includes a circuit device coated with an electrically insulating coating material so as to shorten a distance between circuit patterns of the barrier circuit.