Proximity Sensor - Nokia RM-596 Service Manual

RM-596
System Module

Proximity sensor

Proximity sensor (N1104) Rosa Long is connected to RAPU via a single GenIO. Power supply voltage is provided
from VAUX1 output of EM ASIC. The proximity sensor is an optical reflective sensor mainly comprising of an
optical transmitter LED and optical receiver photo transistor. The proximity sensor is used is to detect indirect
impulses from the transmitter to the receiver to measure reflections from the reflective surface.
One of the typical applications of the proximity sensor is for using the proximity INT output as an indication
to SW of a phone being present near to human ear while attending a call. In such a case, the human body
will act as a reflector, due to which more IR rays fall on the photo transistor of the proximity sensor and the
o/p of the proximity sensor goes from LOW to HIGH. This LOW to HIGH transition is used as an indication to
SW of the presence of a reflector (human body in this case). SW can then switch off the display as the user is
not looking at it while attending the call. This helps in current saving. Similarly, when the user moves the
phone away from the ear, the proximity o/p goes from HIGH to LOW. This is an indication to SW that there
is no reflector nearby and the display should be switched on.
Issue 2
Figure 56 Touch system block diagram
Figure 57 Proximity sensor
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