e-STUDIO167/207/237 © 2007 - 2008 TOSHIBA TEC CORPORATION All rights reserved
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About reflection type photosensor
The reflection type photosensor is comprised of an infrared light emitting diode and a phototransistor. It
uses pulse modulation to detect an original.
Fig. 6-11
The light emitting diode is driven by a pulse having a 130 µsec. cycle and an 8 µsec. ON time. When
the phototransistor receives the same signal as this pulse, it is determined that there is an original. The
pulse modulation is performed inside the reflection type phototransistor.
130 µsec
LED Phototransistor
Original
8 µsec
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