Physical quantity measurement device including a thermal flow rate sensor with a ventilation flow path

A physical quantity measurement device, comprising:

• a thermal air flow rate sensor;
• a ventilation flow path that prevents a sealing of a cavity portion on a back surface side of a diaphragm of the thermal air flow rate sensor;
• a lead frame that has a mounting surface on which the thermal air flow rate sensor is mounted;
• and
• a flow passage forming member that is disposed on a back surface opposite to the mounting surface of the lead frame,
• wherein the ventilation flow path is formed by a first through hole communicating with the cavity portion and provided on the lead frame, a second through hole that is opened on the mounting surface and provided on the lead frame, and a connection flow path defined between the lead frame and the flow passage forming member and connecting the first through hole and the second through hole,
• wherein the connection flow path has a plurality of flow paths connecting the first through hole and the second through hole and includes a plurality of vertical flow paths extending in a vertical direction along a shortest path between the first through hole and the second through hole, and a plurality of horizontal flow paths extending in a horizontal direction in an area between the first through hole and the second through hole so as to cross the vertical flow path in the area between the first through hole and the second through hole and connecting the vertical flow paths adjacent to each other, and
• wherein the plurality of horizontal flow paths extending in the horizonal direction are alternately disposed in a zigzag pattern.