| 摘要 |
PROBLEM TO BE SOLVED: To suppress harmonic noise or electromagnetic noise from an electronic component in a case to the outside or from the outside to the electronic component by forming a conductive film at least partially on the bottom face of the case and bringing the conductive film to the ground potential along with a circuit board. SOLUTION: An electronic component made of piezoelectric material (e.g. a quartz oscillator) is contained in a case 3 made of ceramic material or resin material. A conductive film 1 of same material as a terminal part (subjected to metallization or metal stiffening) is formed at least partially on the bottom face of the case 3 and connected with the ground potential of a mounting a circuit board 2. Consequently, the case 3 is shielded entirely. Since shield effect of the bottom face of the case 3 is enhanced, harmonic noise or electromagnetic noise from the direction of the circuit board 2 mounting the case 3 is suppressed efficiently. Furthermore, the effect of noise from the case onto the outer circumference is also suppressed.
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