| 摘要 |
PROBLEM TO BE SOLVED: To provide a crystal vibrator in which the plane area of a crystal piece having a gradient (bevel-working) on the outer circumference is reduced sharply. SOLUTION: A large number of AT cut crystal pieces of rectangular planar shape having a long side and a short side are thrown into a hollow container having a curvature in the inner circumference. The crystal pieces are polished along the inner circumference of the hollow container as the hollow container rotates to obtain a crystal vibrator where a gradient is provided on the entire outer circumference of the crystal piece from the opposite major surface sides and the central region is made flat. The ratio L2/L1 between the length L1 of the crystal piece in the long side direction and the length L2 of the flat portion is set in the range of 0.24-0.33, and the ratio D1/T1 between the thickness T1 of the crystal piece and the depth D1 from opposite major surfaces in the outer circumferential center of the gradient at the opposite ends in the long side direction is set in the range of 0.30-0.38. COPYRIGHT: (C)2008,JPO&INPIT
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