Laser generation
God said, "Let there be light," and there was light. For example, red light, blue light, infrared light... (Previous article: Red light, infrared light, and blue light—which to choose?)
However, the concept of lasers was proposed by Einstein in 1917, and Maiman did not create the first laser beam in human history until 1960.
Therefore, lasers are not a light source that appears in nature, but a light source that we humans have actually created.
Applications of lasers in photoelectric switches
With so many types of light sources, why choose lasers for optoelectronics? Here, we must mention the advantages of lasers compared to ordinary red light. Compared to ordinary red light, laser light is more concentrated, has excellent focusing, and the light spot can be made very small.
I can't help but recommend our PinPoint light source. Although it uses an LED light source, it's quite similar to a laser (previous article: SICK Optoelectronics' black technology: PinPointLED).
The differences between laser and PinPoint are as follows:
How small can a laser spot be? Let's look at the image below, showing different spot sizes at the same distance. It's clear that the second laser is the smallest.
Because lasers are so bright and have such small spots, they are used in photoelectric switches to easily detect tiny objects and handle applications requiring high positioning accuracy.
For example, the thin-film detection below uses a laser-type photoelectric switch. Because the laser spot is extremely small, it can stably detect the edge of a single thin film without being affected by gaps or even nearby thin films.
Detection of thin film
For example, the WL4SLG-3 series laser-type transparent object detection photoelectric sensor can easily distinguish and count the bottles through the tiny gap between them, even when viewing closely side-by-side. If ordinary red light were used, the large spot size would prevent the bottles from being distinguished.
Laser light source through a small gap for detection
Because the laser spot is small and its divergence is minimal, it can also be used to precisely locate small objects. For example, in the small object detection shown in the image below, a laser-type photoelectric switch is used, eliminating concerns about the spot being too large to detect.
Detecting small objects
Ensuring laser stability
A small light spot size alone is not enough, because in industrial applications, various light sources can unexpectedly appear around the sensor. To avoid interference from other light sources, SICK's laser optoelectronics undergoes anti-light interference testing before leaving the factory, such as suppressing strong light and alarm light interference.
To ensure the highest accuracy in object recognition, the sensor's focus and beam calibration must be adjusted before it leaves the factory to meet the requirements for detection stability.
Laser protection
Based on the harm and degree of damage that lasers cause to human tissues, lasers can be divided into four categories.
◆Class I lasers: pose no danger to the human body during use, and will not damage the eyes even when viewed directly.
◆Class II lasers: Occasionally seeing them will not harm the eyes, but prolonged direct viewing will damage the eyes.
◆Class III lasers: Direct eye contact with these lasers can cause eye damage; therefore, viewing the laser with the naked eye should be avoided. These lasers do not cause thermal damage to the skin.
◆Class IV lasers: These lasers can cause serious damage to the eyes and skin, and protective measures must be taken.
Fortunately, SICK's laser optoelectronic switches all use Class I or Class II lasers, thus minimizing eye damage.
SICK Laser Optical Switch
SICK's product family of photoelectric switches with laser light sources is as follows:
W4SL
W9L
W12L
H18L
WTT12L (TOF principle)*
WTT2SL (Time-of-Flight Principle)
WTT190L (TOF principle)
WTT280L (TOF principle)
W27L
W8L
W130L
W100L
V18L
And this laser family is constantly expanding to meet everyone's various application needs.
* It is worth noting that our WTT12L (TOF principle) is the only laser photoelectric sensor in the world that supports large-angle detection of highly reflective objects.
