It’s 1990, and an enthusiastic voice announces over the loudspeaker, “Attention K-Mart shoppers, there’s a Blue Light Special in electronics.” The iconic, ever-changing, temporary sale was always a highlight when I shopped at my local K-mart as a child with my parents. The rotating blue light mounted on a roller cart could be seen from afar, standing out over the merchandise in the long aisles. K-Mart’s blue lights signaled a deal you might not have been searching for but couldn’t resist. I always wondered, why blue? Why not green or red? My guess is that blue does have some unique qualities and differentiators, including its wavelength in the light spectrum.

Light is a fascinating wonder, and one could spend a lifetime studying its characteristics. But let’s focus on how light relates to object detection. Different wavelengths within the visible and non-visible spectrum react differently to various materials and shapes. Blue light is the hyperactive visible light with a shorter wavelength, making it more powerful. This is important because your application is unique and deserves the best solution.

 Let’s discuss why blue light photoelectric should be on your shopping list.

Blue light has a better range with dense targets

Blue light’s high energy allows it to return to a diffuse sensor even after encountering dense materials. For example, when detecting a roll of carpet or dark fabric like an upholstered car seat, blue light can penetrate these materials better than other wavelengths, such as red light, which might be absorbed and be difficult or fail to return to the sensor. 

Blue light tackles transparent objects better than what?

Blue light is more effective with transparent objects. Clear objects are tricky; they allow most light to pass through, making it difficult for light to return to a diffuse sensor. Red light sensors often struggle with this challenge. However, blue light’s shorter wavelength and higher energy help return more light back to the sensor giving it greater reliability and speed.

Blue light can overcome highly reflective targets

Consider shiny and oddly shaped targets, like a disco ball. The light reflects in various directions, making it challenging for the sensor to receive a return signal. Again, if you expect the light to return to the sensor, blue light, with its higher energy and shorter wavelength, is more capable of returning to the sensors, ensuring accurate detection.

In closing, sensors come in various sizes, technologies, and light colors to reliably fit the needs of the market. We all have challenging applications and often try to solve them with traditional sensors. Most photoelectric sensors use red or inferred light. When selecting a sensor to fit your needs, understanding the benefits of blue light might provide the solution you need.