Patent ID: 7355684
Filing Date: 2008-04-08
Classification: G01B

Abstract:
1. A system for quantitatively measuring a gap, the system comprising: a first source of light; a first sensor spanning a first gap distance, said first sensor having a first Fabry-Perot interferometer which modulates light received from the source; a second sensor spanning a second gap distance, said second sensor having means for controllably altering the second gap distance which is a second Fabry-Perot interferometer that optically cross-correlates the modulated light; a third sensor spanning a third gap distance, the third sensor having a third Fabry-Perot interferometer with a static third gap distance; means for verifying the second gap distance; a correlation burst signal detector; means for conveying light between the first source of light, the first sensor, the second sensor and the correlation burst signal detector; and means for comparing a first correlation burst signal received from the first sensor with a second correlation burst signal received from the third sensor, the first and second correlation burst signals produced by the second sensor that optically cross-correlates modulated light, to quantitatively determine the first gap distance.