| 摘要 |
PROBLEM TO BE SOLVED: To increase the acoustic pressure of a sounder and to prevent the destruction of the sounder due to the intrusion of static electricity by providing a sound emitting hole penetrating through a casing and the sounder in the casing so that the sound emitting opening of sounder confronts the opposite direction to the sound emitting hole. SOLUTION: A sounder 15 is fixed on a substrate 17 by a fixing means such as solder 18 and packaged in a casing 12 so that the sound emitting opening 16 faces the opposite direction to a sound emitting hole 14. The sounder 15 is mounted close to the side of the sound emitting hole 14 in such an extent that the substrate 17 is not in contact with a side wall 13. Thus, since the substrate 17 and the side wall 13 of casing 12 are provided with a prescribed gap apart, the casing 12 does not vibrate and utter an abnormal sound due to the vibration of the sounder 15 during sounding. Even when static electricity intrudes into the sound emitting hole 14, static electricity does not intrude into the sound emitting opening 16 provided by facing the opposite direction to the sound emitting hole 14, neither the driving circuit of the sounder 15 is destructed nor CPU, etc., runs away. |
