Optical Alignment Head
Original Publication Date: 1983-Mar-01
Included in the Prior Art Database: 2005-Feb-06
Alignment of a light colored object having a black alignment bar is accomplished by imaging the black bar onto a two-element light detector. The difference between the signals from the two elements increases with misalignment and vanishes in the aligned position. The ratio of the two signals may also be used in the alternative with certain advantages.