CCTV exposed that the anti-blue light film is less effective than plastic wrap. Is it just a product for fleecing the gullible?

There's no need for me to go into too much detail about applying a screen protector to your phone, right?

Anyway, since the popularization of smartphones, applying screen protectors has basically become one of the most popular things among the general public in our country.

From soft films to hard films, classic ultra - clear films and blue - light - blocking films, to the later segmented AR films, anti - drop films, frosted films, hydrogel films, matte films, etc., people have really gone to great lengths to protect our phone screens and have been very enthusiastic about it.

(Image source: Lei Technology)

Of course, people's obsession with screen protectors has also supported a large number of merchants selling phone screen protectors.

This has led to a chaotic situation in the current market for screen protector products. For products with the same selling point and even using the same picture, the price difference can reach 10 times or more. Especially for the most common blue - light - blocking films, the prices range from 5 yuan to 150 yuan.

Interestingly, for such products, the chaotic pricing may be just the smallest problem.

Many merchants claim that their so - called blue - light - blocking phone screen protectors can "filter harmful blue light" and "protect your eyes". As a result, consumers subconsciously think that such screen protectors can block the blue light from the phone screen and protect our eyes, giving us a sense of reassurance when we brush short videos late at night or stay up late playing games.

But is this small screen protector really that magical? The trigger for this matter has to start with a recent investigation by CCTV.

Are blue - light - blocking screen protectors less effective than plastic wrap?

Recently, a program on CCTV News Channel focused on the popular blue - light - blocking films on the market.

The program group purchased 9 types of phone screen protectors claiming to block blue light from multiple online and offline merchants through formal channels, with prices ranging from 9.8 yuan to 140 yuan. All of them claimed to have the function of blocking blue light. They then entrusted a professional testing agency to conduct a "pre - assessment" of their core indicator - the blue - light blocking rate.

The results were astonishing. Through comparative tests, the blue - light blocking rates of 4 products were between 0.1% and 16.4%, and the blue - light blocking rates of another 5 products were between about 40% and 50%. However, there was still a significant gap compared with the "over 90% blue - light blocking rate" that merchants vowed to claim on the product pages.

(Image source: CCTV News)

That's not all. To make a comparison of the effects, the program group also tested the household plastic wrap that is commonly seen in our daily lives.

The test results showed that the blue - light filtering effects of some so - called "high - tech" blue - light - blocking films were almost the same as those of a thin layer of plastic wrap. The only advantage of these products is that they are at least harder than plastic wrap and are suitable for being applied to phones for protection.

In other words, this stuff is simply a waste of money.

(Image source: CCTV News)

This report has sparked a lot of discussions among consumers on social platforms. Many people suddenly realized and began to look through their orders, recalling which exaggerated promotional slogans had impressed them when they made the purchase.

However, this does not affect the proliferation of similar products. According to my observations on major e - commerce platforms, "blue - light blocking" has almost become a selling point that every merchant casually mentions. In addition to the relatively standard "filter harmful light", there are also claims like "scientific eye protection" and "rare - earth eye protection".

It can even be said that most screen protectors try to be associated with eye protection.

(Image source: JD.com)

As for the price? The cheapest one on JD.com is only 4.9 yuan, and you can even find even lower prices on Pinduoduo.

I simply selected one product with sales of over 80,000. This product claims to block 90% of blue light and is sold at only 13.8 yuan for two pieces.

The product reviews are not very satisfactory. Under these popular reviews, there are a large number of real negative feedbacks, such as "poor light transmittance and clarity" and "ghost images after application, making it dizzy to look at the phone". However, almost all of them are related to the actual effects, and almost no consumers mentioned the blue - light blocking effect.

Why does this happen?

In my opinion, this is because the human eye can hardly distinguish blue light. Compared with visual fatigue that many people can't perceive, the deterioration of the display effect is obviously easier to notice. Moreover, there is no mandatory national standard for phone blue - light - blocking films at present, which has also led more and more manufacturers to pass off inferior products as good ones in the "blue - light blocking" field.

The question is, since it's difficult for the naked eye to perceive blue light, is the so - called blue - light blocking just a sham from start to finish?

Even if it can really block blue light, it might still be a waste of money

Objectively speaking, the blue - light blocking technology itself is not a waste of money.

Technically, the light emitted by the phone screen does contain blue light with a wavelength between 400nm - 500nm. Among them, the part with a shorter wavelength and higher energy (about 415nm - 455nm) is considered to potentially damage the retina and affect the secretion of melatonin, thus interfering with sleep under long - term and high - intensity exposure.

The original intention of blue - light - blocking films is to "target" this harmful blue light.

There are basically two ways for products on the market to achieve this goal.

The first way is relatively straightforward, which is to add some special substances that can absorb blue light to the material of the film. This is called absorption technology. When the light comes, the harmful blue light is absorbed by it. Since the complementary color of blue is yellow, this kind of film itself or when applied to a white screen will look a bit yellowish. That's the reason.

(Image source: CCTV News)

The other way is more advanced, using optical reflection technology.

Manufacturers will coat the surface of the film with many layers of nanoscale coatings, like a Roman shield formation, specifically reflecting the harmful blue light back and preventing it from entering your eyes. This kind of film can be very transparent and doesn't affect the color much, but when you look at it from certain angles, there will be a faint blue - purple reflection on the surface of the film.

In short, for those transparent screen protector products, the blue - light blocking effect is basically negligible. Just remember this.

(Image source: JD.com)

Here comes the key point. Do you think that knowing the principle means you'll be fine when buying a real blue - light - blocking film?

Well, not really.

In fact, even if you buy a genuine product that meets the technical standards, it still has an inherent contradiction that can't be resolved.

You should know that blue light is one of the three primary colors for screen color display. If, as some merchants claim, "block 99% of harmful blue light", the screen color will definitely be completely ruined. Everything you see will look like it has an old newspaper filter, seriously affecting the user experience.

Moreover, many blue - light - blocking films sacrifice the light transmittance to achieve the effect, making the screen darker. To see clearly, you may subconsciously turn up the phone brightness. As a result, it not only consumes more power, but also makes your eyes work harder and get tired more easily.

For example, the film that CCTV took for testing has a blue - light blocking rate of 50% and a light transmittance of 50% as well.

(Image source: CCTV News)

In other words, isn't the manufacturer simply blocking 50% of the screen light?

After such an analysis, it doesn't seem excessive to call a film with uncertain effects, which may change the screen color and even make your eyes more tired, a "waste of money".

The key to eye protection lies not in the film, but in your habits

By now, you may feel a bit disappointed. Does it mean we can only stare blankly at the screen?

Actually, no. Entangling ourselves with a small screen protector is putting the cart before the horse. The real revolution in eye - protection technology has already taken place inside the phone.

In fact, major manufacturers like Honor, Xiaomi, and OPPO are no longer just talking about screen protectors. They are investing real money in screen technology. Honor has developed the "Oasis Eye - Protection" technology, Xiaomi has the "Green Hill Eye - Protection" technology, and OPPO even claims to have invested over one billion yuan in this field.

Compared with simple hardware blue - light blocking, they are solving more fundamental and crucial problems, such as "flicker" that many people can't feel but makes the eyes tired, natural light that allows the screen to automatically adjust the brightness and color temperature according to your surrounding environment, and circularly polarized light that allows the human eye to receive light evenly and thus reduces irritation.

These built - in eye - protection modes and technologies in the phone are systematic projects written into the system's underlying layer after a large number of scientific verifications by the manufacturers. They optimize from the light - emitting source, and their effects are far beyond what a third - party screen protector can achieve.

Of course, no matter how advanced the technology is, it's just an aid.

After all, there's no shortcut to protecting your eyes. No matter how good the eye - protection screen is, it can't withstand you turning off the lights and holding the phone close to your eyes for three or five hours. Using the phone less and looking at the scenery more may sound simple, but it's more effective than any screen protector.

In my opinion, the popularity of blue - light - blocking films just shows our desire for health. However, protecting eyesight is never a one - time consumption. Instead of constantly switching between various "black - tech" screen protectors, you'd better first turn on the eye - protection mode in your phone system and then really start practicing those simple but effective good eye - using habits.

After all, what we want is for technology to truly serve us, rather than letting a "plastic wrap" add to our health concerns under the drive of anxiety.

This article is from "Lei Technology" and is published by 36Kr with permission.