| 摘要 |
PURPOSE:To etch the glass without causing the devitrification and crystallization of the glass by flame-polishing the glass at a temp. higher than the transition point, annealing, etching with an etchant contg. hydrofluoric acid, and irradiating with light. CONSTITUTION:The usual hard or soft glass is heated to a temp. higher than the transition point and lower than the softening point, and flame-polished with a flame of an oxyhydrogen burner, etc. to remove the latent cracks, then annealed, etched with >=2 kinds of etchants contg. hydrofluoric acid, and irradiated with light. The glass can be etched without causing the devitrification and crystallization of the glass in this way, and the glass having smooth surfaces and without any light scattering which is suitable for the optical glass can be obtained. When the etching is applied to the bulb glass of a high-pressure discharge lamp, the once-used bulb can be reutilized by the etching.
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