Circuit arrangement for evaluating the output of a photodiode unit
First Claim
1. A circuit arrangement for determining the angle of incidence of optical radiation, comprisinga plurality of closely spaced photodiodes which each have a respective individual field of view corresponding to optical radiation having a different respective range of said angle of incidence,central photodiode means having a combined field of view which includes all said individual fields of view,a plurality of analog comparators, each having an input coupled to a respective one of the outputs from said plurality of photodiodes, a second input of each of the analog comparators being coupled to a common reference voltage,a first analog comparator having an input coupled to the central photodiode means and a second input also coupled to the common reference voltage,reference control means responsive to the output from the central photodiode means, for varying said common reference voltage in accordance with the intensity of radiation detected by the central photodiode.
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Accused Products
Abstract
The intensity of the optical radiation varies within a wide range. The proportion of parasitic radiation registered by the photodiodes (D1 to Dn) increases with increasing radiation intensity. To exclude this parasitic radiation from evaluation, the photodiodes (D1 to Dn) are followed by analog comparators (K1 to Kn) with a variable reference voltage (Uref1). The reference voltage (Uref1) is varied by an analog comparator (Kz1) in porportion to the radiation intensity determined by a central photodiode (Dz).
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Citations
4 Claims
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1. A circuit arrangement for determining the angle of incidence of optical radiation, comprising
a plurality of closely spaced photodiodes which each have a respective individual field of view corresponding to optical radiation having a different respective range of said angle of incidence, central photodiode means having a combined field of view which includes all said individual fields of view, a plurality of analog comparators, each having an input coupled to a respective one of the outputs from said plurality of photodiodes, a second input of each of the analog comparators being coupled to a common reference voltage, a first analog comparator having an input coupled to the central photodiode means and a second input also coupled to the common reference voltage, reference control means responsive to the output from the central photodiode means, for varying said common reference voltage in accordance with the intensity of radiation detected by the central photodiode.
Specification