How Do VFD Displays Work?


Invented in the late 1960s, vacuum florescent displays can be seen in many pieces of technology that we use on a daily basis – and despite the popularity of LEDs, they’re still a good choice for a wide variety of reasons. If you’re interested in using one for a project or you simply want a better understanding of how they work and their applications, we’ve got you covered with a simple breakdown of how these displays work.

Where are vacuum florescent displays commonly used?

First of all, it might be worth learning where you will typically see these displays in use. While they were used much more before LEDs become prominent, you’ll still see them in use in several places today. You might find them in audio equipment, digital clocks and many more pieces of tech that require a simple yet effective display option.

Even LCDs have taken over some of the original common uses of VFDs, now being more common for handheld games and calculators, where vacuum florescent displays were once the most widely used option. 

How do they work?

In general, a VFD will only be able to display simple characters and perhaps even a few predefined words. While there are more complex graphical displays with more options (like different fonts, images, words, etc.), you’ll often find many around your home that only use the basic type.

Essentially, there’s a tungsten metal heated filament (the cathode) that produces electrons. Each segment of the display (the anode) is coated with chemicals called phosphors which glow when hit by electrons. In between the metal and display is a grid that can be switched on and off, which manipulates the flow of electrons.

While this is a simpler version, this is the long and short of it. In many ways, VFD displays work in a similar way to cathode-ray tube TVs. If you know anything about how these televisions work, you might find it easier to understand vacuum fluorescent displays.

What are the advantages of using VFDs?

For the most part, vacuum fluorescent displays can help to combine some of the benefits of LEDs and LCDs. In many ways, they can be a great alternative to both. Light or dark, VFDs are generally clear and easy to see from any angle and further distances. They can also be used in a wider variety of settings, in both high and low temperatures, which can be well worth considering, too. In fact, this is one of the main reasons why they’re more commonly seen on microwaves and electric stoves.

VFDs might not be ideal for every job, but it’s hard to deny that they still have some excellent applications.