In general, with an electronic thermometer for performing body temperature measurement when placed at a measurement site such as the armpit or under the tongue, a liquid crystal display, a printed circuit board, and the like are fixed in a sub-case, the sub-case is arranged inside a main housing, a temperature sensor is housed in a temperature measuring unit, and the temperature measuring unit is provided in the front end portion of the main housing. A temperature sensing unit that senses the temperature at the measurement site and a processing circuit formed by mounting various types of electrical parts on the printed circuit board are connected by a small, relatively rigid lead. The lead that electrically connects the temperature sensing unit to the processing circuit has a terminal portion that is fixed to the printed circuit board and a long portion that extends out from the printed circuit board.
Conventional common “pencil-type” electronic thermometers employ a structure in which the electronic thermometer is completed by inserting the sub-case into a cylindrical main housing through its rear end portion. In this case, if the temperature sensor lead that extends out from the sub-case becomes bent or directionally misaligned, faults occur in which the insertion of the temperature sensor into the main housing does not go well, measurement precision decreases due to positional misalignment of the temperature sensing unit at the tip of the temperature sensor, and product variations (instrumental error) arise between individual electronic thermometers. Aiming for the realization of automation in electronic thermometer assembly therefore requires an improvement in the step in which the temperature sensor that extends out from the sub-case is inserted into the main housing.
For example, JP H9-89680A (Patent Literature 1) discloses an electronic thermometer in which the above-described printed circuit board is extended to the temperature measuring unit, a conductive line is formed in the extension portion of the printed circuit board, and the temperature sensing unit is mounted at the tip of the extension portion, thus ensuring electrical connection between the temperature sensor and the processing circuit via the conductive line.