| 摘要 |
PURPOSE:To simply obtain curved surface ultrasonic vibrators having small variance of the thickness of curved surface piezoelectric bodies and small variance of the thickness of electrodes at high reproducibility by holding a flat plate ultrasonic vibrator between a concave surface block and a convex surface block, deforming the flat plate ultrasonic vibrator by heating and forming a curved surface ultrasonic vibrator. CONSTITUTION:If a flat plate ultrasonic vibrator made by providing electrodes on both sides of a flat plate piezoelectric body 3b cut at high thickness accuracy is held between a concave surface block 5 and a convex surface block having a radius of curvature R and heated, plastic distortion is formed just before brittle fracture due to load stress. Distortion starts at three places, that is near the contact line with the convex R surface block 7 and two places near the contact line with concave R surface block, and speed of distortion near the contact line with the convex R surface block 7 is more than double compared with other two places as the load differs by twice. Accordingly, the center portion of flat plate ultrasonic vibrator starts distortion faster than other parts. With generation of distortion, load applied per unit area becomes smaller and speed of distortion decreases. After lapse of a certain time, the flat plate ultrasonic vibrator is deformed to a curved face vibrator having a radius of curvature R.
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