Patent ID: 7260422

Claim:
A method for realizing a loudness control of an earpiece of a mobile phone in such a way, that unpleasant and harmful loudness levels are avoided for the user by exploiting an optical proximity sensing method, consisting of a photon generating device and photon sensing devices with a common control means also used for the loudness control of a loudspeaker system, comprising: providing said loudspeaker system of said earpiece, said photon generating device, said photon sensing device, and said common control means; starting the driving of said sound generating loudspeaker system and establish a secure threshold sound level within said common control means; setting-up and driving said photon-generating device as primary photon source; establishing and operating two different photon-sensing devices in two different photo channels with basically identical channel characteristics but different spectral responses as determined by either a Photo Diode open to light or a Photo Diode dark or covered, said two different photo channels operating in parallel and commonly fed by said primary photon source and as such delivering a first and a second photo output signal; measuring the distance from a reflective surface by comparing the photo output signals from said two different photo channels at two different periods in time; evaluating said photo output signals from said two photo channels by continuously comparing said first and second photo output signals thus taking into account obnoxious side effects and thus effectively compensating for said obnoxious side effects; comparing said measured distance to the correspondingly equivalent of said established secure sound level threshold value; deciding accordingly to the programmed logic implemented within said common control means with its primary goal, to reduce loudness if distance of said earpiece to said user is small; and generating output signals according to the result of the decision, thus avoiding unpleasant and harmful loudness levels.