Why Do Barcode Scanners Use Red Light?

Have you ever been in line at the supermarket and noticed that when you scan your items a red light comes out? These red lights come out of barcode scanners, and the reason why they are red is actually quite simple!

If you want to learn more about what barcode scanners are and why they use red light, then please keep on reading to learn more!

First Off, What’s A Barcode?

A barcode is a representation of numerals and characters that consist of bars and spaces at varying width which are readable by machines, or barcode scanners.

They are very useful for the swift identification of different products. Barcodes are often placed on packages of products sold in numerous settings, like grocery stores, convenience stores, shopping malls, and much more. 

Barcodes are composed of three different parts. These are as follows:

1). The Quiet Zone, or the margin. The quiet zone is the margin located at both ends of a barcode. The minimum distance between two barcodes, or the outermost bar of one barcode to the next, is around 2.5 millimetres. Quiet zones must be appropriately sized in order for the barcode scanner to be able to read barcodes sufficiently. 

2). The Start and Stop Character. The start and stop characters, as the name suggests, are the characters that are found at the beginning and the end of the barcode data. They differ depending on what type of barcode is at hand.

3). Lastly, the Check Digit. The check digit is the digit that tells you whether or not the encoded barcode data is correct. 

Generally, barcodes can be classified into two types. The first type is the 1D barcodes, which makes use of lines that store information like product type, colour, and size.

The second type is 2D barcodes, which are known to be more complex and can include more information such as quantity, price, and even images. Smartphones and image scanners are able to read 2D barcodes, and not 1D barcodes

As such, barcode scanners work by scanning a red light onto a barcode to interpret the code and decipher information about the product itself.

Why Barcode Scanners Use Red Light

So, Why Do Barcode Scanners Use Red Light?

You’d be surprised to know that the answer is simple: red light is more economic! Barcode scanners like the ones typically found in supermarkets make use of lasers that are known as “diode lasers.”

Diode lasers are known for their ability to operate from electrical power and, of course, for their small size, which contributes to a lot of conveniences. 

Laser diodes are also known as a semiconductor laser, which is capable of causing laser oscillation by flowing electric currents to a semiconductor. Once the current flows to the p-n semiconductor junction of the laser, then a light will be generated and emitted. 

Why does this matter? Well, if you use different materials as the semiconductor, this may lead to different band gaps which ultimately produces different wavelengths of light or basic colours.

Barcode scanners are known to use red laser diodes because laser diodes that emit red light are known to be much cheaper to produce, hence the reason why many barcode scanners use red light.

Essentially, it is all due to economic reasons. Technically, barcode scanners can use any colour of light; however, red lasers are significantly cheaper and much simpler in comparison to other colours.

Red light is also known to have longer wavelengths, which are advantageous because photodiodes, or the reader of the scanner, are known to respond better to these types of wavelengths,

Using a blue light will require a more expensive and specialised laser. However, there are some barcode scanners that use green light because some barcodes cannot be read by red light. 

Why Barcode Scanners Use Red Light


Today, barcodes have made our lives much more convenient, making checking out at the grocery store as efficient as it can be. We can see how technology has truly transformed the way we live our lives every day!

With this, barcode scanners make use of red light to scan barcodes, mainly because lasers that produce red light are known to be much cheaper. With longer wavelengths, red colours are also much more responsive to barcode scanners. However, you may find that some lasers make use of green light, and this is because some barcodes cannot be read by a red light.

If you would like to know more about the best stocktake software and how the right set of software and point of sale systems could help you, give us a call.

ASP Microcomputers are the market leader when it comes to the development of customised and packaged solutions.

This includes Inventory Management, Portable Barcode Readers, Supply Chain Management, Time and Attendance and Asset Tracking to name but a few.

ASP Microcomputers is here to help you run your operations in a smooth and convenient manner by providing you with the right equipment for your company needs.

Contact us so we can sit down and discuss your goals, needs, and business structure. Armed with this information, we can help determine exactly what equipment you need to achieve success.

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