| 摘要 |
Condensation water occurring within a container box (300) is discharged to the outside thereof, thereby keeping the inside of the container box (300) at low humidity with no condensation water therein. The container box (300) has been sealed with an electric circuit unit (210) contained thereby. The container box (300) has: a very small discharge aperture (322) that is formed at the bottom of the container box (300); and a discharge valve (330) that is a non-return valve for closing the discharge aperture (322). Only when the internal pressure of the container box (300) is higher than the external pressure thereof by a predetermined value or any greater value, the discharge valve (330) opens to discharge the liquid existing within the container box (300) via the discharge aperture (322). During the other times, the discharge valve (330) closes to keep the airtightness of the container box (300). |
