Hydrogen detection device and control method for hydrogen detection device

A hydrogen detection device comprising:

• a first hydrogen sensor that detects hydrogen;
• and
• a third detection circuit connected to the first hydrogen sensor,
• wherein the first hydrogen sensor includes:
• a first electrode including a principal surface and a second electrode including a principal surface, the principal surface of the first electrode and the principal surface of the second electrode facing each other;
• a first metal oxide layer in contact with the principal surface of the first electrode and the principal surface of the second electrode;
• a first insulating film covering the first electrode, the second electrode, and the first metal oxide layer;
• a first terminal and a second terminal that are connected, through a via, to another surface of the second electrode opposite the principal surface of the second electrode;
• and
• a third terminal connected, through a via, to another surface of the first electrode opposite the principal surface of the first electrode,
• the first insulating film includes, between the first terminal and the second terminal in plan view of the second electrode, a first opening where the other surface of the second electrode is exposed and not covered by the first insulating film, and
• the third detection circuit includes:
• a third measurement circuit that measures a first resistance value between the first terminal and the second terminal and a second resistance value between the third terminal and at least one of the first terminal or the second terminal;
• and
• a second control circuit that selectively outputs one of the first resistance value or the second resistance value.

A hydrogen detection device comprising:

• a first resistive element, a second resistive element, a third resistive element, and a fourth resistive element that are included in a bridge circuit,
• wherein one end of the first resistive element and one end of the second resistive element are connected,
• one end of the third resistive element and one end of the fourth resistive element are connected,
• another end of the first resistive element and another end of the third resistive element are connected,
• another end of the second resistive element and another end of the fourth resistive element are connected,
• the first resistive element is a hydrogen sensor and includes:
• a first electrode including a principal surface and a second electrode including a principal surface, the principal surface of the first electrode and the principal surface of the second electrode facing each other;
• a first metal oxide layer in contact with the principal surface of the first electrode and the principal surface of the second electrode;
• and
• a first insulating film covering the first electrode, the second electrode, and the first metal oxide layer,
• the first insulating film includes an opening where an other surface of the second electrode opposite the principal surface of the second electrode is exposed and not covered by the first insulating film,
• the third resistive element is a reference element and includes:
• a third electrode including a principal surface and a fourth electrode including a principal surface, the principal surface of the third electrode and the principal surface of the fourth electrode facing each other;
• a second metal oxide layer in contact with the principal surface of the third electrode and the principal surface of the fourth electrode;
• and
• a second insulating film covering the third electrode, the fourth electrode, and the second metal oxide layer, and
• the second insulating film does not include an opening where another surface of the fourth electrode opposite the principal surface of the fourth electrode is exposed and not covered by the second insulating film.