You want to protect your privacy but it hurts your eyes. Is anti-peep film a "tax on your IQ"?

Review expert: Zhou Hongzhi, senior laboratory technician, master's supervisor, School of Physics and Optoelectronic Engineering, Beijing University of Technology

With the development of science and technology, people pay more and more attention to personal privacy protection. In order to prevent people around them from peeping at their information on the Internet, anti-peeping films came into being. However, many netizens also said that anti-peeping films are "IQ taxes" and may also cause damage to the eyes!

So how does the anti-peeping film hurt the eyes? What is the anti-peeping principle behind it?

The main causes of eye damage caused by mobile phones (TV)

There are two main types of light that the human eye receives: passive light—all diffuse light, such as the natural light environment we observe; active light—direct light from various luminous bodies, such as the luminous bodies we see, such as televisions, mobile phones, light bulbs, the sun, etc.

The human eye is a naturally occurring biological organ, a photosensitive organ formed over billions of years by natural reflected light, and is therefore able to adapt to the natural reflected light environment.

Although the light source produced by the luminous materials of televisions, mobile phones, etc. is as close to natural light as possible, the light waves it emits are still active direct light waves with direct light radiation characteristics. Since the directivity of most direct radiation light is essentially different from that of diffuse reflection light, it can cause damage to human eyes.

Therefore, no matter what measures are taken, as long as the fundamental factors of direct radiation are not eliminated, all measures are "IQ taxes".

The principle of anti-peeping film

Anti-peeping film utilizes the characteristics of light such as penetration, refraction, reflection, and diffuse reflection, and creates an anti-peeping effect by changing the internal structure of the mobile phone film.

01 Refraction of light

All objects seen by the human eye have the phenomenon of light refraction, and the same is true for mobile phone films and mobile phone screens. When a person is playing with a mobile phone, if there is no anti-peeping film, then another person next to him can also see part of the content. This is because ordinary mobile phone films cannot prevent the refraction of light.

The anti-peeping film changes the internal structure of the film. It can block the refraction of light. People watching nearby cannot receive the light refracted from the screen and naturally cannot see the image!

The refraction at the edge of the film will produce colorful halos, and the screen content will become blurred, which will have a strong impact on the human eye and cause visual fatigue.

02 Micro shutter optical technology

At present, the privacy films on the market mainly use micro-louver optical technology. Just like the blinds in life, they use the concave and convex directions of the blades to achieve light while blocking the outside view. The technology of privacy films is similar. After the privacy film is attached to the mobile phone, the person who is using the mobile phone can clearly see the screen display content at 90 degrees from the front, but the screen content cannot be seen at the side less than a certain degree, such as 25 degrees or 45 degrees.

This method allows the human eye to see the screen clearly at a vertical angle, but the blurred edges and halo will cause illusions to the human eye if viewed for a long time, resulting in dizziness and blurred vision, which will damage the vision.

Anti-peeping is just a concept. The LCD screen used to use special technology to eliminate the edge viewing angle. Now it uses some method to block the edge viewing angle. This is not progress, but a substitution of concepts.

After applying the anti-peeping film, the brightness of the mobile phone screen will decrease, and the screen brightness needs to be increased to achieve the original visual effect, which is actually not good for eye health.

Regardless of whether we use anti-peeping film or not, we must pay attention to the time of using mobile phones and other electronic products, screen brightness, etc. When we feel eye fatigue, we should stop using them and look into the distance to reduce the impact on vision.

Is “Eye Protection Mode” the preferred setting for screen brightness?

Eye protection mode, also known as "anti-blue light mode", achieves eye protection by blocking blue light.

Blue light has the characteristics of short wavelength and high energy. It can penetrate the lens of the eye to reach the retina, increase the retinal oxidation reaction, produce harmful free radicals, and damage our eyes.

After turning on the eye protection mode, the blue light radiation ratio of the mobile phone screen is reduced, the blue light peak ratio is increased, and the screen brightness and color temperature are reduced. It can be clearly felt that the mobile phone screen becomes yellow and darker, and it is not so white and dazzling.

After testing, the China Consumers Association found that when a smartphone is in eye protection mode, blue light will be reduced by about 30%-40%, which is effective in reducing visual fatigue.

However, blue light will not disappear. Eye protection mode can only play a very weak role in protecting the eyes by adjusting visual light. For most people, the effect of eye protection mode cannot resist the damage caused by playing with mobile phones for a long time. In addition, using eye protection mode under high-intensity light and low brightness of the mobile phone will increase the burden on the eyes.

The only way to protect your eyes is to avoid watching active luminous objects in the dark, including TV, mobile phones, outdoor large screens, etc. Reduce the viewing time of active luminous objects and pay attention to resting your eyes.