Overview
2-31
Service Periodic Maintenance
Contents
Schematics Illustrated PartsInstallation
Touch Screen
The Secondary system display (i.e., the right-hand monitor) is equipped with an array of infrared light-emitting diodes
and a corresponding array of phototransistors that detects the presence and calculates the location of a finger touched
to the CRT. You use this touch screen feature in conjunction with displayed software screens to make mode and
function selections during Workstation operation.
The LEDs and phototransistors are arranged in a rectangular matrix on a touch frame that surrounds the edge of the
CRT. These devices are ordinarily invisible behind the monitor bezel. The touch frame has 43 LEDs on the right-hand
edge, 43 LEDs on the bottom edge, 43 phototransistors on the top edge, and 43 phototransistors on the left-hand
edge. A simple controller associated with the touch screen scans each phototransistor several times a second to
detect beam interruptions, determines the x and y coordinates for the beam interruption, and transmits that information
via RS-232 interface to the System Interface PCB for further processing.
Phototransistors
Infrared Leds
Touch Screen Assembly
To Next Page
Loading...
