| 摘要 |
PURPOSE:To effectively enhance uniform thermal effect and to obtain a jig having excellent thermal resistance and dimensional stability by forming 1/10 or more of the total number of air bubbles in elliptically spherical shape. CONSTITUTION:In a fine air bubble-containing quartz glass jig, 1/10 or more of the total number of air bubbles are of elliptically spherical shape. A cylindrical thick tube which contains spherical air bubbles produced by arc melting is thermally softened in a molding furnace, and then oriented in the longitudinal direction. Then, quartz glass which contains elliptically spherical air bubbles oriented in the longitudinal direction can be obtained. For example, the elliptically spherical air bubbles oriented in the longitudinal direction of the core tube reflect at random incident light in a circumferential direction to enhance the uniform thermal effect in the circumferential direction, and the elliptically spherical air bubbles oriented in the circumferential direction reversely reflect the light at random in the longitudinal direction to enhance the uniform thermal effect in the longitudinal direction.
|
