| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a fluid gauge proximity sensor which is substantially not influenced by external noise, capable to operate in any environment, regardless of the sort or the exposure wavelength of a resist on a surface of a workpiece. <P>SOLUTION: This fluid flow proximity gauge comprises a source of a modulated unidirectional fluid flow or alternating fluid flow; at least one path, having a nozzle and a flow sensor or pressure sensor mounted thereon; the fluid exists at a gap between the nozzle and a target; the flow sensor or the pressure sensor outputs an amplitude modulated signal that varies in accordance with the size of the gap. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
