LED Display Filter

When you make an electronic project with an LED display you can give it a more professional look by placing a filter in front of the display. This has the effect of reducing the glare of the LEDs, it also hides the display and makes it easier to read. You can buy thin pieces of plastic film that act as filters from electronics stockists, however I found another way of making a cost effective filter, by simply salvaging the lenses of 3D glasses that you purchase when you go to see a 3D film in the cinema.

The lenses of 3D glasses contain Polaroid lenses that have a grey tint to them which I found is ideal for placing in front of red LED displays. To remove the lenses you need a sharp craft knife to cut them into the shape and size that you require to match the size of your display.

WARNING! - Be careful when using a craft knife because they are very sharp. Children should ask an adult to cut the lenses to size

One of the nice properties of Polaroid lenses is that if you place the two lenses on top of each other and rotate them you can either increase or decrease the amount of light that shines through.

Depending on how bright your LED display is you can either use one or two lenses in front of your display. I am really pleased by the effect that this creates, take a look at the pictures below of a digital clock that I built using four 7-segment LED displays. As you can see the filter gives a dark appearance to the display but still allows the display to be read when it is illuminated.