Everything you need to know about watch backlighting
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A large assortment of classic wrist watches is presented in the corresponding section of our catalog, and smart wearable devices are available at this link. We also recommend reading the material “Types of glass in wristwatches”.
Different watches and their dials
When there were only classic wristwatches with hands, discussions about backlight were mostly limited to special luminescent coatings. But then electronic models with other backlighting technologies started to gain popularity. And in recent years, for some customers, a wrist watch is primarily associated with smartwatches, where no backlights are needed (in fact, they are in the display).
The classic and smart wearable devices are technically very different devices, even if they look good on our wrists. They differ in functionality, battery life, and in most cases they have different dials and ways of backlighting them. You can learn more about all the differences in a separate material “Smart watches or classic ones: What to choose?”. Here we will focus on the backlights. But first let's briefly talk about the design of the dials themselves.
Since traditional and smart watches have different dials, their backlighting is also different. |
All mechanical watches and many traditional quartz models involve a hand dial. Here you will see a dial backing with numbers or markers, above which the physical hands move. Quartz models can also have an electronic dial. This is essentially a monochrome screen. But most smart watches have a color display with a more advanced matrix, although if you really want, you can also find models with hands.
If for hand dials the main challenge is often reading the time in the dark (the content is simply not visible), for colored electronic dials — bright external lighting (glare appears, the image is dim). And it is the backlight that should solve these two problems. In traditional watches its role is performed by LEDs or non-volatile light-accumulating elements. Smart watches also have backlighting, but it is located in the display — next to the matrix or not in it.
How is backlight implemented in smart watches?
In smart watches, an electronic display provides the dial backlighting. Almost all current models have a color display. The basis of such a screen is a matrix supplemented with LED backlighting or consisting of organic light-emitting diodes. The latter are independent sources of light. In all modern smart watches there is no problem with the visibility of the dial in the dark. But as for glare and bright external light, there may be nuances.
Let's take a brief look at the most popular smart watch display types:
- TFT. One of the simplest color displays with backlight. Not always bright enough to effectively combat glare;
- IPS — LED-backlit display, balanced in terms of price and image quality;
- OLED. This is a screen based on self-luminous organic diodes. Generally operates well in all lighting conditions as it has high contrast and can be very bright. For instance, the Apple Watch 8 boasts a brightness rating of 1000 nits. However, OLED displays are more expensive than IPS and TFT;
- different variations of AMOLED. Essentially, this is a subtype of OLED displays with similar strengths and weaknesses.
The Transflective screen manufacturing technology stands out noticeably against the background of the displays listed above. This is a type of liquid crystal display that has two operating modes. In the dark or when there is a lack of light, the LED backlight functions. And in bright light, the display reflects it and provides excellent visibility.
In bright sunlight, the Transflective display looks almost the best. But in other conditions, color rendition is inferior to analogues. |
Among other things, the devices had excellent battery life. However, in 2023, the manufacturer began to use AMOLED more often in its new products. Such a screen consumes more energy, but it is noticeably better in terms of color gamut and color reproduction quality (more users want a juicy and colorful picture)
Types of backlights in regular wristwatches
In classic watches, the method of backlighting dials is different from smart watches. Even in models with electronic displays, it works a little differently. Here, the displays are usually monochrome, and such a display reflects external light (so it is resistant to glare and bright light). It turns out that backlighting is needed to read data in the dark. How is it implemented? By adding LEDs to the electronic device.
By the way, speaking about the backlighting of the dial of ordinary watches, it is necessary to make allowance for the movement used. For example, mechanical models are non-volatile and do not require power sources. Accordingly, the option with electronic backlight in the mechanical wathes is not possible by default.
Typical electronic backlight of a digital watch. |
Many manufacturers use different brand indications and give names to their backlighting functions (technologies). At the same time, they can be both exclusive and not so much. The choice of backlights at Casio is quite variable, where even within the electronic variation there are different subtypes, for example, Super illuminator — LEDs of increased brightness or Auto Light — with automatic activation.
It is extremely difficult to list all the brand names of the backlights, and it is not necessary. The main thing is to understand their main variations:
- Electronic. As mentioned above, it requires power, so it is only used in quartz watches. Most often, one or more LEDs are used. In the first case (this variant is sometimes called micro LED), the backlighting is uneven, but economical: it is often used in models with a small dial. A higher quality model is one with several diodes, but the battery life is shorter.
- Luminescent. This option is widely adopted in mechanical and frequently seen in quartz watches. It involves applying a special light-accumulating coating to the hands and dial markers, sometimes exclusively to the hands. While no separate power source is needed for this backlight, occasional exposure to light is required for charging — whether in a well-lit room or sunlight. The composition of the coating determines the quality and duration of the backlight; for instance, zinc sulfide provides a few hours of backlight, whereas materials like strontium aluminate, such as in SuperLumiNova, can glow throughout the night. This is a common feature in watches from renowned Swiss brands.
Here's what SuperLumiNova looks like. |
- Electroluminescent. This is actually a subtype of the previous variation, but it is often considered a separate type. It is used in quartz watches. A special coating (usually with phosphorus in its composition) is applied to the entire dial. To activate the backlight, an electrical impulse is required (it is provided by a battery). As a result, photons are emitted and a rather bright cold backlight appears. Such backlighting is more economical than conventional electronic, but over time fades and dims. This technology is widely used by Casio (it is called Illuminator, but it should not be confused with Super illuminator) and Timex (Indiglo).
Timex Indiglo EL backlight. |
- Tritium or radioluminescent. This is another non-volatile backlight — more complex and expensive. This is where special mini-tubes are placed on the marks and hands. They are filled with radioactive isotope tritium and have a luminescent coating (which reacts and lights up). It is safe, "charging" in the light is not required, and the service life of such a backlight reaches 25 years. Only a few brands use this technology, including Luminox (called Light Technology) and Traser (Trigalight).
The tubes in Luminox Light Technology are clearly visible. |
- Combined. Watch manufacturers often experiment with various solutions to mitigate the drawbacks of individual backlighting methods. For instance, a combination of electronic backlight, light-accumulating coating, and even fluorescent + tritium may be employed. The Night Vision collection by Victorinox is noteworthy for integrating SuperLumiNova with three LEDs, including a strobe light. Interestingly, there's a secondary battery dedicated to powering the electronic component, while the main battery drives the quartz movement.
How is the backlight activated in different watches?
In addition to the fact that there is a backlight, you should also pay attention to how it is activated. In other words, whether additional user actions are required to make the dial readable in the dark.
In smart watches, additional sensors (gyroscope or accelerometer) are usually responsible for activating the display - it is activated automatically when the user turns the hand with the device toward him or her. Today, the Always on Display (AoD) function with a constantly active display is becoming more and more common. Thanks to this function, smart watches are even more similar to the classic watches, no additional hand movements are needed, however, the battery is discharged faster due to AoD.
With the Always on Display function, the minimum display backlight is always active. |
In quartz watches with an electronic dial, the backlight is most often activated by a separate button. It can be realized in different ways: it will be on as long as you press it, or the LED operates for a fixed time (a few seconds). Rarely provided for automatic activation: and both at a shortage of light, and by turning the wrist. But both options discharge the battery more actively.
Non-volatile backlight watches usually do not require any additional activation. A glance at your wrist is enough to see the time. But in the case of conventional luminescent technology, it is important to remember that the luminescent elements must be "kept in the light" for some time. Here it is important not to hide the dial under the cuffs of clothes and/or not to store the watch in the nightstand.
Watches with no backlight at all: why is that possible?
Color smart watches cannot have light sources at all: their display simply will not operate without diodes. But classic wrist models sometimes do not have backlighting. It's most often a forced action that occurs in:
- inexpensive watches: its abandonment is due to the desire to simplify the manufacturing procedure and reduce the cost of the product;
- small watches. Let's say that due to the ultra-thin body, there may not be splace for placing LEDs or using tritium tubes;
- mechanical watches that have thin hands. As a rule, this is typical for small or designer models. If the hands are really miniature, then it is very problematic to apply a luminescent composition to them.
Mechanical watches with thin hands may not have a backlight at all. |
Sometimes manufacturers do not use backlighting for other reasons. For example, it may be absent in expensive luxury watches. As a rule, such a watches is purchased not for functionality at all, but as a status element or an addition to a fashionable image. Most often these are models for women (like Frederique Constant FC-703VD3SD4), but models for men can also be without backlight.
Conclusions on the watch backlighting
Backlighting in smart wearable devices is an obligatory element of a color display, although we don't usually think about it. In a normal hand watch, backlighting is not technically a must have. But it is still better to have a backlight. This option increases the convenience of using the watch when there is a shortage of light, and also slightly transforms the appearance, because a beautiful luminescent coating and/or uniform LED-lighting pleases the eye and makes us once again make sure that we have a really high-quality device on our hand.
Also, do not forget that frequent use of the backlight of a quartz watch drains the battery. It should not be used without reason, because replacing the power supply is not such an easy task for beginners.