Flow rate detection device and method for manufacturing the flow rate detection device

A method for manufacturing a flow rate detection device, the flow rate detection device including:

• a housing including a sub-passage configured to partly pass a fluid, which flows through a main passage to be measured, and
• a circuit board partly fixed to the housing, the circuit board being equipped with:
• a flow rate sensor, which is provided in the sub-passage and configured to detect a flow rate of the fluid to be measured, and
• at least one electronic component,
• the method comprising:
• preparing the circuit board equipped with a physical quantity sensor, which is different from the flow rate sensor and configured to detect a physical quantity of the fluid to be measured, the physical quantity sensor including an electrode part electrically connected to the circuit board and a sealing resin in a liquid form;
• applying the sealing resin in the liquid form to a physical quantity sensor mounting surface, which is formed on the circuit board and equipped with the physical quantity sensor, to cover the electrode part;
• and
• curing the sealing resin after the sealing resin is applied, wherein
• the physical quantity sensor mounting surface includes:
• a mounting region surface including a place where the physical quantity sensor is located, and
• a peripheral region surface extending around the mounting region surface,
• a wettability of the mounting region surface for the sealing resin in the liquid form is higher than a wettability of the peripheral region surface for the sealing resin in the liquid form, and
• the sealing resin in the liquid form is applied to the mounting region surface of the physical quantity sensor mounting surface in the applying the sealing resin.