OPTEX FA Transparent Object Detection Sensor

  • OPTEX FA’s transparent object detection sensor has been widely adopted in various industries, including not only the food industry but also the automotive and semiconductor industries. Those who use this sensor regularly praise the sensor’s stable and accurate detection capabilities.
    Moreover, the sensor can detect any transparent object, making this transparent sensor lineup the best in the industry.

Transparent Object Detection Sensors

Transparent object detection sensors are a type of retro-reflective sensor.
Because transparent objects transmit light, detection is not possible with a normal retro-reflective type sensor. Transparent object detection sensors use reduced hysteresis to detect transparent objects.
However, because simply reducing hysteresis increases the likelihood of chatter and of malfunctions arising due to noise, optical system and circuit design improvements are required for transparent object detection.

    1. Assuming light attenuation is 3% when passing through the workpiece, the total attenuation of light will be 6% before returning to the sensor.

With a retro-reflective type sensor, light passes through the workpiece twice, meaning the received light amount is more likely to be different compared with other methods.
The higher that difference (attenuation) in the amount of light received is, the easier detection will be.


Transparent object detection sensors are generally used for detecting passage of glass or plastics. Other various applications include slack control for transparent film.

  • Detecting glass plate
    for automotive

  • Detection of plastic bottle passage

  • Transparent film upper and lower
    limit control

Recommended Transparent Object Detection Sensors
  • Digital Laser Type
    DR-Q Series
    ・Sensing distance: Max. 4 m
    ・Digital adjustment function
    ・Built-in ASC function

    This transparent object detection sensor allows for long-distance detection.
    The digital display allows users to perform adjustments while checking the displayed values. In addition, thanks to the teaching method, setting is possible by simply pressing a button.

  • Transparency Detection Type
    KR-Q/SR-Q Series
    ・Stabke detection even at close
    ・Visible red spot light
    ・Narrow view design which makes
        detecting through gaps possible

    The KR-Q and SR-Q series are OPTEX FA’s best-selling transparent object detection sensors.
    These series offer the industry’s highest accuracy amongst LED light source sensors. Four models are available with various sensing distances.

  • Transparency Detection Type
    Z3R-Q/ZR-QX Series
    ・Long range detection at 2 m
    ・Uses red LRD for simple light axis
    ・Industry standard size

    The Z3R-Q/ZR-QX series embodies the industry’s standard transparent object sensor size.
    The ZR-QX200N coaxial retro-reflective type transparent object detection sensor offers top-of-the-line detection stability compared with other LED light source sensors.

For more information, select a transparent object detection sensor from the table below according to detection target, features, or other specification.