摘要 |
The present invention provides a tension mask having a frequency distribution with improved vibration damping. The tension mask includes a center portion between two edge portions. The tension mask also has a parabolic frequency distribution between the edge portions whereby the center portion has a central frequency distribution value and the edge portions have a relatively lower peripheral frequency distribution value characterized in that the range of variation between the center and edge portions frequency distribution value is in the closed interval of about 8 Hz<=DELTA&LE;12 HZ.
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