| 摘要 |
PURPOSE:To eliminate a decrease in yield due to falling and the trouble of separation, by etching a quartz thin plate for a longer time at the groove bottom part of a turning fork than at other parts. CONSTITUTION:Some part of a quartz thin plate 13 as the groove part of a tuning fork is etched for the 1st time to form a long-sized hole 14. Then, the 2nd etching is performed to form a tuning-fork type quartz piece 15 and a frame body 16. As a result, the oscillating piece 15 is etched by the 2nd etching work for a longer time at a groove part 17 than at the circumference of its coupling part 18 to reduce the unetched part of the groove bottom part extremely, reducing the unbalance in frequency between both the arms of the tuning fork extremely. Further, the circumference of the coupling part 18 is etched only in a short time, so the oscillating piece 15 has no danger of falling from the frame body 16. |
