Optical interruption sensor with opposed light emitting diodes

摘要

An optical-interrupter provides a mechanically integrated electric light source and electric light sensor positioned across a gap to transmit a light beam across the gap that may be interrupted with an opaque vane. The optical-interrupter uses conventional LEDs for both the light source and a light receiver. An integrated circuit comparator may be used to provide an adjustable threshold for the determination of whether the light beam is blocked.

主权项

1. A photosensor-photodetector assembly comprising:
a support defining an unobstructed light path through a gap from a first to a second position; electrical terminals adapted to receive a direct current supply voltage and ground voltage for the photosensor-photodetector assembly and to provide an electrical output from the photosensor-photodetector assembly; a solid-state light transmitter and solid-state light receiver attached to the support in the first and second positions so that light from the solid-state light transmitter may be received by the solid-state light receiver, the gap sized to permit an optical blocking element to pass into and out of the gap to block the light from the solid-state light transmitter to the solid-state light receiver; a biasing circuit providing an electrical bias to the solid-state light transmitter and an electrical bias to the solid-state light receiver, when a direct current supply voltage and ground voltage are received by the electrical terminals; detection circuitry including a threshold detector connected to the solid-state light receiver to compare a signal from the solid-state light receiver to a threshold signal to provide the electrical output; wherein the threshold signal varies with the supply voltage to compensate for changes in the illumination of the solid-state light transmitter with changes in supply voltage; and wherein the solid-state light transmitter and solid-state light receiver are both light emitting diodes; and wherein a substantially continuous electrical bias that is a substantially proportional function of the supply voltage is applied to the solid-state light transmitter.