Method and apparatus for determining the location of graduated marks in measuring applications

摘要

Apparatus for determining the location of graduated marks in measuring comprising source means for emitting electromagnetic radiation towards electromagnetic radiation sensors, and a measuring mark moveable between the source means and the sensors from one measuring position to another in a direction of measurement transverse to the direction of radiation, the mark being adapted to cause a restriction in the cross-sectional measurement of radiation between the source means and the sensors, the sensors being adapted to detect the location of the radiation restriction by sensing radiation intensity proportional to the area of their receiving faces upon which such radiation falls in use.