How Do Reflective Signs Work?

Have you noticed how popular reflective signs are? All types of industry use them from construction to road traffic safety, and these days we tend to take them for granted. However, have you ever actually wondered how they work? The most common perception is they use mirror type technology, but that’s not the case especially where road safety is concerned.

You see if you were to use mirror type technology you wouldn’t actually see the image of a road sign reflect back at you, and that certainly wouldn’t help in terms of safety! In the following few words, we aim to explain in simple terms how different types of reflective signs work.

How Diffused Reflection Works

This type of reflection is usually used with paper or cloth, so is more common in other areas of industry. Without getting too technical, when a concentrated beam of light is shone onto the surface it bounces back in a number of different directions. This results in a soft and somewhat unfocused reflection which is why it’s not used within the road safety industry. There’s no point in driving when it’s dark only to be met with a reflective warning sign that cannot be read properly.

How Retro-Reflection Works

Retro-reflection is one of the most popular ways of designing reflective signs on the market today, and it uses technology that’s not unlike that of the cat’s eyes you see in the middle of the road. It’s worth noting this type of reflective sign first appeared about 50 years ago and started life using a type of glass bead technology. Tiny glass beads are coated in aluminium that has been vaporised so they repel light. They are then made into signs by being embedded into plastic that’s transparent.

When light is shined on these beads, it hits the back of the reflective spheres in two places. This means the beam of light is reversed both horizontally and vertically. As a result, the sign appears to be lit up back at the source of light.

The Latest Technology

The very latest technology on the market uses something that’s often referred to as “cubes corner”. Instead of glass beads, microscopic prisms are used that have three reflective surfaces (as oppose to two), and when light hits them it meets at one point. Just the same as retro-reflection, when light hits the prisms it bounces off two surfaces resulting in a horizontal and vertical trajectory. The reason why this technology is becoming ever more popular within industry is because the reflected light has a wider angle, and therefore makes signs more obvious without blinding you when you look at them.

So, now you know how reflective signs work and the next time you’re out on a drive during the night, you can “reflect” on the fact you know why it is you can see a sign so clearly without the need for electricity. Although, it’s best not to dwell on this too much or your attention may be taken away from the road which could result in an accident!