Lighting up your face: the not-so-secret secret of your phone screen

A smiling woman in a darkened room looks at her phone and the light from the screen gently illuminates her face.

That familiar glow. You know the one we mean – the cool light that radiates out of your phone screen, illuminating your face. The giveaway of someone using their phone in the cinema or checking their socials under the covers. It’s become so ubiquitous that there are literally thousands of TikToks where couples rib each other about their comparative screen brightness and just as many more on how to adjust your settings. It’s extraordinary that only fifteen years ago this wasn’t even a thing, yet today it has its own cultural references!

That’s because, according to the GSMA , over half the global population now owns a smartphone. Which equates to around 4 billion or so screens of varying brightness. Most owners will know what brand of phone they are holding, but the vast majority won’t have a clue about its components. Which is why what we’re about to tell you may come as a bit of a surprise: your smartphone screen may well have been manufactured using Canon equipment .

Canon Tokki was among the first in the world to develop an OLED panel production system and is now the market leader. And as if to underline how important the role of this system is, ‘Tokki’ even means ‘special equipment’ and System-ELVESS is just that: an all-in-one automated factory which builds OLED screens, layer after complex layer – from the substrate up – and then encapsulates them so they resemble the final product we are all familiar with.

The entire machine is more than 100 metres in length and designed for high volume, stable and continuous operation. This all comes about through a combination of technologies and expertise which, while they might not immediately scream ‘Canon!’ to you, once you understand a little about them, you’ll see how they fit into our world.

A stack of eight smartphones, viewed from the side, of different styles and colours.


(A space from which the air has been completely or partly removed)

Canon Tokki moved into the vacuum technology business in around 1983, pre-dating the birth of OLED by a few years and smartphones by some 25 years! So, it’s a foundational part of the business that soon came to be an essential one to display production, which operates at such precision that even air molecules can cause inaccuracies. Therefore, many parts of this complex process must be conducted in a vacuum – obviously to minimise impurities, but also to allow lower temperatures to be used in the deposition process (which we’ll come onto later) and this protects the fragile light emitting particles that are the basis of OLED displays.


(Decoration, composition, or configuration according to a pattern)

Each smartphone screen is formed of multiple functional layers and the electrode layer of the display provides its ‘electrical pathway’. These circuit patterns are ‘drawn’ onto the glass surface using a kind of high-precision etching called Flat Panel Display Lithography. We are well-known for our expertise in semiconductor lithography equipment and the two are very similar but, as you might expect, displays aren’t quite so complex as a miniscule semiconductor chip.

We are, after all, a company that prides itself on our excellence in manufacturing and the many thousands of patents we hold.”


(The action of depositing something)

This too is a familiar theme in the Canon world, as it’s actually very similar to inkjet printing. – something we’re rather excellent at, if we do say so ourselves. In fact, deposition techniques are used across the multiple layers that comprise an OLED smartphone display, including laying down the patterning mentioned above. In the case of the RGB layer, light-emitting particles are heated in a vacuum until they turn into a gas and subsequently adhere to the surface of the glass in a very thin and even layer – like the finest of printed snowflakes – but only on very specific areas. Which brings us to…


(Arrangement in a straight line or in correct relative positions)

To make sure that the patterns ‘printed’ on all layers is incredibly precise, areas are masked out and this requires the assistance of ‘alignment technology’. Here, high-precision cameras (you knew there would be some in here somewhere, right?) are used to meticulously control the position of the mask and the glass substrate. And as you might imagine, this too needs to happen in a vacuum.

Knowing this, is it really so unexpected that our technology may be sitting in your hand? Or the hand of the person next to you? We are, after all, a company that prides itself on our excellence in manufacturing and the many thousands of patents we hold, registering nearly 3000 last year alone.

We have R&D centres all over the world, working in a huge number of disciplines, including (but certainly not limited to!) Artificial Intelligence for healthcare, video analytics, satellites, medical technologies, material sciences, semiconductor devices, OLED and FPD, and, of course, advanced optics and print. In fact, we’re in such a large number of ‘surprising’ places, you might find yourself picking up your phone and having a quick check from time to time.