Method for generating the light radiation in an optical sensor system, in particular for tracking a linear textile material, and electrical circuit for controlling a light-emitting diode in such an optical sensor system.

摘要

The invention relates to a method for generating the light radiation, in particular for tracking a linear textile material, wherein the source of the light radiation is a light-emitting diode (1). During the duration of the generation of the light radiation by the light-emitting diode (1), the voltage dropping across the light-emitting diode (Ud) is tapped off and the size of the feed current (Id) is set as a function of the tapped voltage. Thus, the influence of the temperature of the light emitting diode (1) on the intensity of this light radiation is eliminated. The invention also relates to an electrical circuit for driving a light emitting diode (1), wherein the anode of the light emitting diode (1) is connected to the output of the operational amplifier (2) and the cathode of the light emitting diode (1) via a series resistor (R3) to the is connected to the negative pole of the feed, wherein the light-emitting diode (1) a first resistor (R1) which is switched between the anode of the light-emitting diode (1) and the negative input of the operational amplifier (2), and a second resistor (R2), the between the negative input of the operational amplifier (2) and the cathode of the light emitting diode (1) is connected in parallel, and where the positive input of the operational amplifier (2) is connected to the voltage (Ui) for adjusting the operating point of the radiation source, wherein in this way, the supply current (Id) for the light-emitting diode (1) in dependence on the voltage across the light-emitting diode (1) voltage is regulated such that the egg nfluss the temperature of the light emitting diode (1) on the intensity of the light emitted from the light emitting diode (1) light radiation (1) is eliminated.