Clear label sensors hit the market in 1995 in a response to industry demand for a label sensor that worked with clear labels (which had become all the rage in the 1980s) and did not require eye-marks.
Lion Precision's LRD2100 was the first clear label sensor introduced to the packaging industry. It was a differential capacitive sensor and the industry's first capacitive sensor for clear label sensing. Because it was a new technology, the price was much higher than existing optical solutions that could not detect clear labels, but the packaging industry quickly embraced the new clear label sensor solution.
The price soon came down as production quantities increased and the clear label sensor revolution was on.
Differential capactiive sensors cannot reliably detect labels with metallic or high-carbon ink materials. To create a clear label sensor without this limitation, Lion Precision developed the LRD6110 single-ended capacitive sensor. This new technology detects nearly all label types and materials. It also featured a more detailed setup indicator to help the operator adjust the sensor.
The only type of label that presented a problem was solid metallic/foil labels. The labels don't require a clear label sensor, but the ultimate goal is to create one sensor that can detect any type of label to prevent the need to change label sensors. In response to that goal, Lion Precision designed the LRD8200 ultrasonic clear label sensor. Ultrasonic technology is not affected by the metallic materials in labels and is capable of sensing all material types. However, ultrasonic technology is affected by other factors such as layering and those unusual webs that just happen to be resonant at the ultrasonic frequencies making them very difficult to detect.
The search continues for the ultimate clear label sensor that can truly do ANY label. That technology hasn't yet been developed, but the packaging industry is certainly much better off than before the clear label sensor revolution.