| 摘要 |
PURPOSE:To reduce noise due to the shift of a lens, by forming a venthole to discharge the air enclosed between a fixed part and a mobile part which allows a shift of the lens toward an optical axis. CONSTITUTION:A mobile part includes a coil 4, a coil holder 5 and a lens 7, and a space 13 is inevitably formed between the mobile part and a fixed part. Furthermore a gap 3 of a magnetic circuit part is reduced in order to increase the efficiency, and therefore the space 13 is substantially closed. The air enclosed in the space 13 repeats compression and expansion owing to the shift of the mobile part toward an optical axis. This produces noise. In this respect, a venthole 15 is provided at an area such as a bottom surface part of the holder 5, etc. to discharge the enclosed air. |
