| 摘要 |
PURPOSE:To improve effectively frequency characteristics, especially sound pressure in a low frequency range by providing a speaker and a passive diaphragm in the case of a miniaturized electronic timepiece and coupling and spaces the both together. CONSTITUTION:In the case 25 of the electronic timepiece, the speaker, a display part 2, and the passive diaphragm 26 are arranged in a plane and the diaphragm of the speaker 21 is coupled with the passive diaphragm 26 spacially. A composite circuit 23 and a battery 24 are arranged on their reverse surfaces. An acoustic wave from the speaker 21 passes through the diaphragm 11 to generate an acoustic wave in positive phase. An out-of-phase acoustic wave on the reverse surface of the diaphragm 11 strikes the battery 24 and case 25 to be put in reverse phase again to obtain a same phase with the speaker 21, allowing the diaphragm 26 to oscillate. Therefore, frequency characteristics are improved to improve especially sound pressure in a low frequency range deteriorated greatly owing to size reduction and thickness reduction. |
