Ricoh IWB-D1 Service Training page 7

Model K-C3.5L
How does it Work?
Position Sensors and Reflecting Plates
3 reflecting plates are attached to the right, left, and bottom sides of the
LCD panel.
Reflecting plates reflect light to the same direction of the incident light
emitted from the right and left position sensors.
When the pen tip contacts the surface of the LCD panel, light reflected to
the position sensors from the 3 reflecting plates is intercepted. This
interception allows detection of the pen position by measuring the 3
points of the triangle; Right position sensor, Left position sensor, Pen tip.
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