| 摘要 |
PURPOSE:To measure efficiently the size of a sample with high accuracy without receiving the influence of the material of the sample by measuring the size of the sample by a method for superposing a cursor line and setting the threshold value of the pulse waveform obtd. when the sample surface is subjected to linear scanning in accordance with the measured value thereof. CONSTITUTION:The pulse waveform obtd. by linear scanning of the sample surface by using a linear scanning circuit 19 is amplified by an amplifier 14 and is then inputted to a threshold setting circuit 21. The signal of the measured value of the sample size measured by the method for superposing the cursor line using a cursor matching circuit 18 and a length measuring circuit 20 is inputted to the circuit 21 from the circuit 20 in this stage. The threshold value of the circuit 21 is set by the output signal from the circuit 20. The threshold value of the circuit 21 is automatically set in accordance with the measured value if the operation for measuring just once the sample size by the method for superposing the cursor line is carried out even if the sample material is different. The subsequent size measurement is automatically carreid out by using such threshold value.
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