Is face unlocking harmful to eyes?

Face ID, Iris Scanner and some other face and iris recognition technologies are using infrared to shine directly into users' eyes.

Some high-end smartphones are using infrared sensors to verify user identity instead of fingerprint sensors. Both Face ID on iPhone X and Iris Scanner (iris scanning) on Galaxy S10 have this technology. Does it have an adverse effect on the eyes when we use it every day?

Apple introduced Face ID on iPhone X. (Photo: Wired).

This is a problem that many people care about. Infrared rays have been used in many areas of life, but there are few documents explaining what risks to direct eye contact.

In addition, Samsung, one of the pioneering manufacturers, introduced infrared scanning technology to the phone, also denied responsibility for the health caused by Iris Scanner and recommended caution when using it. This raises the concern of users.

What is infrared ray?

Infrared or infrared radiation (IR) is a type of electromagnetic radiation with a wavelength longer than visible light but shorter than microwave radiation. Like the light we are seeing, microwaves and radio waves, IR is a non-ionizing radiation. It cannot separate electrons from atoms and does not cause cancer.

Infrared radiation is present in many places, including in nature. Oven baked bread, sunlight, campfire emits infrared rays. 95% of the energy generated by fluorescent bulbs is also converted into infrared rays. Even the human body naturally produces infrared rays. It is a scientific basis for people to use thermal infrared cameras to monitor enemy's activities in spy-action action films and secret agents.

IR infrared rays do not have ionization ability, safe for users.(Photo: wikiHow).

Infrared LED (IR-LED) is integrated in smartphones belonging to the type of near infrared ray (NIR), with wavelengths between 700 nm and 900 nm. It lies between the boundary of light and infrared rays.

Both light and infrared are capable of heating the object it hits, depending on the intensity and duration of the projection. Long-term exposure to high-intensity light or infrared rays (such as looking straight at the light, the sun) can cause your eyes to damage photosensitive cells and cause cataracts.

With low intensity, the human eye can be visually impaired if exposed to light from an illuminated or infrared source at a distance of 1 mm for 20 minutes continuously.

The main concern is the intensity of people exposed to IR. We can control looking at the light. High light intensity will cause glare and discomfort, people will immediately unconditional reflex by narrowing their eyes, closing their eyes or looking away.

But the human eye does not react to infrared rays, so we do not know when this type of radiation has reached a dangerous level. However, the type of infrared radiation used on smartphones is also the safest, near infrared ray.

Operation principle of infrared sensor

Iris Scanner and Face ID are biometric identification forms used to unlock phones and important applications such as shopping, credit cards, and banks. Both have simple and fairly similar operation mechanisms. Apple and Samsung smartphones are equipped with infrared LEDs that emit near infrared rays and a camera capable of receiving infrared light.

Face ID uses a tiny infrared matrix to map faces in 3D.(Photo: Gadget Hacks).

With Iris Scanner on Samsung phones, the device will project IR-LED rays and take an IR image. The smartphone then evaluates the detailed eye image of the user and collects it with the image stored in the data. If it matches, the phone will allow unlocking.

Apple's Face ID not only captures the eye. It scans the entire face by shining hundreds of tiny IR-LED rays. The infrared camera will capture the image and set up the face structure map in 3D and compare it with the identity data installed on the iPhone.

Many people wonder if Samsung and Apple actually use any infrared spectrum on their smartphones. There is no exact figure yet, even the two do not mention IR-LED in the machine's specifications section. However, for the infrared camera to collect data accurately, it needs infrared wavelengths in the range of 870 - 950 nm.

According to Renesas classification, IR-LED on the phone is the safest infrared radiation for health. OSHA standards also evaluate products equipped with IR not strong enough to heat the user's eyes and do not cause eye damage when used at normal levels.

Misunderstandings about IR

When searching on Google with the "IR iris scanner" tag, you may find that many people pose health problems when using phones with infrared sensors. Most people are unaware that in their disclaimer statement, Samsung warned of some negative impacts on children, people with epilepsy and people with insomnia. Surprisingly, Apple did not make similar recommendations with Face ID.

Search results show many false information about the harmful effects of IR on smartphones. Many news sites, technology websites offer inaccurate and meaningless content, making users more confused. Although scientific research has shown that IR on smartphones is safe for users.

IR does not cause cancer, the infrared ray nature does not have the ability to ionize. High-frequency X-rays, gamma rays and ultraviolet rays are ionizing forms of radiation and they can cause cancer. Anyone who says that radio waves, microwave ovens or infrared light causes cancer suggests they have no knowledge of this problem.

IR-LED is not a laser.(Photo: Technobezz).

Another misconception, many people still think IR-LED is laser. The laser is a high-energy monochromatic light waveform, moving in a single direction. IR-LED on smartphones has a wide wavelength, which is diffused by lenses and filters to illuminate the user's entire face.

Scientists have published an experiment to illuminate infrared rays in the rabbit's eye, causing many people to fear. Basically the rabbit has eye damage, cataract. But if you read the content carefully, it can be seen that the infrared type used in the experiment is completely different from IR-LED on smartphones.

In this experiment, the scientists used large infrared ray lamps, which were directly projected into the rabbit's eye every 5 to 10 minutes. Meanwhile, infrared LEDs on Samsung smartphones and Apple are smaller than an ant and emit infrared every 10 seconds. Infrared lights on smartphones also use short wavelengths, while in the above experiment, infrared light lamps use ultraviolet (UV), visible light, near, far, and medium frequencies. Everyone knows that UV rays are strong enough to cause sunburn on the skin, far infrared rays heating in the microwave, boiling water.

Is IR on a smartphone harmful to health?

Infrared-based devices have been around for a long time in the market, but with IR-LED, for the first time infrared rays are direct and user eyes, so we need to make sure this technology is safe.

According to Renesas and Smartvisionlight, direct contact with IR for less than 10 seconds is classified as low risk. In order for the IR-LED in the phone to harm the eye, you will have to keep it 1 mm away from your eye for a continuous period of 17 minutes. This cannot be done with the Galaxy or iPhone X, as both products limit IR exposure for 10 seconds and they will not emit infrared light unless the device is 20 cm from the user's head.

Studies have also shown that some people who are sensitive to light may be at greater risk of eye damage due to infrared rays but this is a rare case. People who suffer from this syndrome almost have trouble walking under normal light.

From what is known above, this time can be sure that IR on Iris Scanner and Face ID will not hurt the user's eyes.

However, this technology has only recently appeared in the last few years, no one can check whether the use of ID-LED continuously for 20-30 years has caused any harm. Users can completely turn off this feature but will waste modern technology on an expensive smartphone.