| 摘要 |
PURPOSE:To perform stable and sure end part detection, by detecting the net amount of revolution of arm while the turn table turns by one revolution, through the slit in which the transmitted light amount is continuously increased or decreased with the arm revolution and the slit transmitting light pulsively. CONSTITUTION:The moving slit plate 3 is placed on the horizontal revolution shaft 2 of the arm 1 to form the first slit 4 in which the width of opening is continuously changed and the second slit 5 arranging the opening of the same size with a given pitch. The light from the light source 6 is detected with the photo detection elements 10, 11 respectively through the slits 4 and 5 and the fixed slits 8 and 9. The analog signal from the photo detection element 10 is sample-held at the sample hold circuit 15. The output and that inverting it at the inversion circuit 16 are picked up for the changing part at the differentiation circuits 17 and 18 and they are inputted to RSFF 21. FF21 stores the increase and decrease at the sampling at previous case, the output of FF21 opens any gate, the pulse signal from the element 11 is inputted to the counter 23, and it is reset to a given numeral every one rotation of the turn table. The end point is detected from the content of the counter 23. |
