Bright, brighter, brightest? Why a display backlight system is more than meets the eye

By Frank Ploenissen | 25 January 2024

Let there be light!
If only it was that simple in the world of display backlight systems.

To begin with, the human eye doesn’t perceive light in a linear way. So, if you’re looking to achieve a super-bright result, your display will need a huge amount of energy – more than double, in fact. For energy critical devices, this often means compromising brightness for battery life and the decision is taken to run with a low brightness display.

Shooting more light through a TFT cell will wash the colors out, so even the cell itself needs to be modified to convert a dim display to a sun-defeating lantern that is still capable of showing saturated colors. High-performance LEDs can also help to reduce heat, yet additional passive cooling techniques are still often required.

Proper backlighting is complex even in advanced edge or back lit arrangements, where LEDs are arranged in a line (edge lit) or array (back lit). They form miniature points of super bright light and subsequently take on the characteristic of a spotlight. Therefore, a system of light shaping elements needs to convert the multiple tiny dots into a uniform area of light.

The end goal is high brightness, low heat dissipation and the correct white point. Which, in and of itself, is not straightforward. A proper mix of wavelengths is required to ensure a wide color space for the emitted picture. Because what is considered ‘white’ in one context may not necessarily be the same as ‘white’ in another. And in a final layer of requirements: the whole backlight system must be as thin as possible.

All these considerations for just one function?

When we describe it this way, it sounds impossible to achieve, but we do ­–again and again, millions of times with best results. So, we know and understand just how important each of these elements are for application designers. The selection of proper display brightness, and in some cases even the correct customization of a display backlight is mission critical and may well decide between failure and success of a final product introduction.

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About Author

Frank Ploenissen - Marketing Manager Display Integration, Avnet at Avnet

After getting his diploma in electrical engineering, Frank entered the world of display solution and distribution in the year 2000, holding product responsibility for several display and touch lines. Starting 2007 he worked as a sales and marketing manager for a design and manufacturing company of CCFL and LED backlight drivers, and afterwards established the German branch for a Austrian display and solution provider. In 2013, Frank joined former MSC which in turn was bought by Avnet.
In his current role as Marketing Manager Display Integration, Frank and his team supports the Avnet team and their customers concerning the integration of display products into customer applications and steers and extends the product lines of SimplePlus and MipiPlus display solutions.
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