Automated Light Source Monitor
Original Publication Date: 1981-Feb-01
Included in the Prior Art Database: 2005-Feb-10
A light source monitor for a projection printing tool, having an adjus scanning slit consists of a sense head 1, a trimmer box 2, and a controller 3. The sense head 1 has thirteen photovoltaic sensors 4 (for a 57 mm array) which are mounted in a wafer chuck 5 so that sense head 1 can be loaded into the tool using the existing chuck-handling mechanisms. Sensors 4 are arranged to correspond with the arc of the slit. Eleven of the sensors 4 are used to determine the intensity and energy at each slit correction point, while the remaining two sensors are used to measure the slit speed. Trimmer box 2 is used to calibrate the output of each sensor 4 to a known absolute standard. Controller 3 consists of an operator keyboard and display, a 16-channel A/D converter and a microprocessor with associated memory and I/O.