Logic Output Opto Devices

Details

Published on Tuesday, 21 November 2017 18:31

Most of the Opto devices sensor devices on the market are designed with analog outputs (photodiodes, phototransistors) that requires an analog to digital conversion to interface with the application. Light in Motion offers a range of devices that include the digital conversion, hence simplifying the whole application design and manufacturing.

This range of logic devices goes from pure detectors (optical input, logic output) in various forms, to Optointerrupters (LED drive input, logic output) with multiple form factors and connectivity arrangements.

1.       Benefits of Logic output:

      ·         Simplified interface circuitry

      ·         Sharp response (transition from low to high or high to low)

      ·         Hysteresis that prevents unsettled states when the optical input changes

      ·         Fast response (rise time and fall time of 100ns)

      ·         Choice of logic function (buffer or inverter)

      ·         Choice of output stage configuration to accommodate the application Vcc voltage and impedance, as well as allowing logic operations in case of multiple channels.

2.       Product families:

     ·         H21LXX : industry standards 3mm gap Optointerrupters with mounting tabs.

See Product characteristics.

     ·         H22LXX : industry standards 3mm gap Optointerrupters without mounting tabs.


See Product characteristics.

     ·         QVE00112 : high resolution 3mm gap Optointerrupter with built in LED drive and 3 connecting  wires: Vcc, Vout, Gnd.


See Product characteristics.

     ·         QSE258 : stand alone detector in a sidelooker, through hole package. It allows to insert the logic  detector functionality to the application with a small footprint.


See Product characteristics.

     ·         LIM158FS : stand alone detector in a surface mount low profile package. It allows to insert multiple logic detectors in the form of an array.


See Product characteristics.

     ·         QSA15X : stand alone detector in an hermetically sealed metal package, particularly suited for high  temperature, high humidity or corrosive environment conditions.


See Product characteristics.

     ·         Customized products: the logic functionality can be added to many Optointerrupters designs. It can  also be implemented on our chip on board platform to make a variety of products, from reflective    encoders, to remote sensors using plastic optical fiber and data transmission links.

3.       Possible applications:

• Encoders: depending on the required form factors and the resolution, various solutions can be implemented using the logic output detector devices. One example of this is the use of the QVE00112 for motor control. See details here.

• Random position object sensors: by building an array of logic detectors and linking them to form an “AND” logic function, it is possible to detect objects moving in a predetermined volume. See details here.

•  Accurate flag detection: H21LXX and H22LXX series can be used to detect the position of a flag moving in the slot. Owing to the sharp logic response, the detection is accurate and unambiguous.

• Data transmission: Logic detectors are ideal for data transmission, either in open space of with optical fiber. The fast switching times and the hysteresis are factors that result in low Bit Error Rate.