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Backlighting

Posted by Nancy Figueroa | July 2021

When you are shopping for a laptop, you probably focus on the technical features and the last thing you pay attention is to the stetics.

Considering a good keyboard is important, because this component is the bridge between human command and computer processing and probably you will spend a lot of time using it.

Now imagine that you work in a dimly lit place, of course you will need a backlit keyboard.

But, do you know how it is possible to put a backlight on the keyboard?

So, here we’ll talk about some technologies and methods to make incredible devices with backlight.

Backlight keyboard

What is Backlighting?

Backlighting is when we add components to illuminate a small area or the front surface of a device, for example, a membrane switch from an electronic device.

This light can be activated by another function from the device to advise the user if they need to take an action, like a red Led that indicates when something is wrong or a green led indicating that everything is alright.

Another example is when this light can illuminate the entire area of the device when the light from the room is turned off.

The systems to get backlight involve components that could be surface-mounted like leds or printed like phosphor inks, and of course inverters or power supply.

How can I add backlighting to the membrane switch?

Here listed four alternatives to incorporate backlighting into a membrane switch or some project that needs a little bit of light.

Backlighting by LED
  1. Backlighting by LEDS (Light-Emitting Diodes)

    • This is a low-cost technology and it’s ideal to illuminate specific areas.

    • You can see them like indicator lights or keys in many devices.

    • Leds are not recommended for entire areas, at least that you combine them with other material.

    • Have a useful life between 50,000 and 100,000 hours, it depends directly on the environment the device is exposed to.

    • Has a low energy consumption.

    • And can be single or multi-colored.

Electroluminescence keyboard
  1. Electroluminescence by Phosphor inks

    • This kind of illuminating is created by printed inks that contain light-emitting phosphors. A layer with this ink is added between the circuit and the graphic overlay.

    • This kind of backlighting is ideal when the application requires more visibility at the surface, for example a keyboard.

    • This option used to be more expensive than LED, but the custom design can be extraordinary.

    • Has not many colors available as the option with LEDs but the appearance is elegant and modern.

Optical fiber backlight

3. Backlighting by Fiber Optic

    • This kind of backlight is created by a thin layer of fiber optic that is added between the circuit and the graphic overlay.

    • The fibers are grouped into a small cylindrical connector coupled to a light source, usually a LED.

    • This option has a low consumption of energy

    • Also can handle high temperatures and humidity

    • The cost use to be moderate

ITO materials

4. Backlight hybrid

    • The previous alternatives to get backlight in an application can be combined, for example with a guide of LED’s mounted on a PET film we get a better light distribution.

    • Another example is when we combine phosphor inks with ITO materials, this alternative will be ideal for electroluminescent lamps, but it's important to take care about details to avoid drain of light.

Choosing any of the alternatives to add backlight to your project needs some considerations, for this reason it is necessary to know that any of these techniques requires a power source and maybe needs connectors but thanks to the expertise of the design team, we can suggest some recommendations that will help to improve the application.

Let's talk about your project

Would you like to add some of the backlight techniques to your project? Please let to know us to: sales@ensel.org