Light detection circuit

摘要

An electronic light detection circuit for detecting an intensity modulated light signal on a photosensitive element under backlight condition. The circuit comprises the photosensitive element, in particular as a light position detector for detecting a striking position of the light signal spot within a detection window, an amplifier with high input resistance connected to an output of the photosensitive element and a backlight suppression circuitry.;The backlight suppression circuitry is connected to the output of the photosensitive element in parallel to the amplifier and comprises an electronic active resonator structure. The active resonator, structure is designed in such a way to provide a load impedance to an output of the photosensitive element with a low load impedance for low frequencies for suppression of natural and artificial backlight-saturation of the photosensitive element and a high load impedance at the frequency of the intensity modulated light signal.

主权项

1. An electronic light detection circuit for detecting an intensity modulated light signal on a photosensitive element under a backlight condition, comprising:
said photosensitive element, including a light position detector for detecting a striking position of the light signal spot within a detection window; an amplifier with high input resistance connected to an output of said photosensitive element; and backlight suppression circuitry connected to the output of the photosensitive element in parallel to the amplifier, the backlight suppression circuitry including an electronic active resonator structure with at least one operational amplifier, configured to provide a load impedance to an output of the photosensitive element with:
a low load impedance for low frequencies for suppression of natural and artificial backlight-saturation of the photosensitive element, anda high load impedance at the frequency of intensity modulation, wherein the low load impedance is lower than the high load impedance for backlight suppression by draining low frequency photo-induced currents from the output of the photosensitive element.