| 摘要 |
PURPOSE:To obtain an etching speed whenever it is necessary by dipping a specific gravity detection float in chemical for etching and computing the etching speed through a position detection encoder and a specific gravity detector according to variation in specific gravity. CONSTITUTION:Specific gravity detection floats 7a-7d move up and down at different specific gravity values corresponding to the specific specific-gravity variation range of the chemical 6 for etching and the displacement by the upward/downward movement is detected by position detection encoders 8a-8d and transduced into electric signals respectively. The specific gravity detector decides the specific gravity according to those signals and a computing element 10 computes the etching speed on the basis of the specific gravity data, so the etching speed which is necessary during etching operation is obtained at any time.
|
