The "blue light" of electronic products, also known as the problem of light absorption by filters, has finally attracted the attention of those in the display industry. Regarding "blue light", if you ask users of electronic products, they will say that blue light will make your eyes tired, so they wear anti-blue glasses to prevent them. And if you ask the display technicians, sometimes they will answer indifferently: "Although there are many claims, but there is no evidence." If you go to an optical shop, you will see the shop saying "Protect your eyes from LCD TVs and LED lighting." Advertisements such as "Blue-ray-damaged anti-blue-ray glasses". An ophthalmologist will say that the human eye has two functions: "imaging" and "clock". Blue light has a great relationship with the eye. Some ophthalmologists have begun to remind people to be wary of the effects of blue light on human eyes.

For those in the electronics industry, it is very important to have a thorough understanding of this issue. At this time, the "1st International Symposium of Blue Light Society", which discussed the issue of Blu-ray, was held in Tokyo in June 2013. The following will introduce some of the contents published by the society, and review the past restrictions on the impact of electronic products on the human body, hoping to help you understand blue light.

First, let's talk about which spectrum of light each electronic product emits. Since there is no public data, it may be difficult to understand. Among the three light sources, the LED uses blue light and yellow fluorescent materials to produce white light. The problem is that there is a peak (blue peak) at the wavelength (460nm) equivalent to blue light. When using LEDs as the backlight of a liquid crystal display, the light intensity of the blue peak can be controlled, but it is difficult to change the peak wavelength. Therefore, displays and lighting using LEDs may affect users due to the blue peak.

This conference was held at the appeal of Kazuo Tsubasa, a professor in the Ophthalmology Department of Keio University School of Medicine, Japan. Famous ophthalmologists, psychiatrists, electronic component researchers, European CIE (International Commission on Illumination) and LED manufacturers and other relevant persons from related institutions and industries around the world delivered speeches at the conference. Unfortunately, people in the display industry did not give a speech, but the theme and content of the conference are worth listening to.

The author basically has no medical expertise and cannot give a detailed explanation. Please forgive me. The blue light problem is mainly the following two aspects. The author also mentioned earlier that the human eye has two important functions: imaging and clock. First of all, if the eye is over-exposed to blue light, it may damage the eyeball, which is an impact on the imaging function. Secondly, if the eyes keep watching blue light day and night, it may cause abnormal circadian rhythm (biological clock with a cycle of approximately one day), which is an impact on clock function. Based on these two points, this society clarified the blue light problem from many angles, with the purpose of preventing the future from leaving a curse.

may affect the two major functions of the eye "imaging" and "clock"

First, let’s talk about the effect of blue light on the imaging function. Experiments in mice have shown that if the eyes are over-exposed to blue light for a long time, the possibility of causing "age-related macular degeneration" cannot be denied. Age-related macular degeneration is a difficult disease, and treatment trials using iPS cells have now begun. According to the ophthalmologist who delivered the speech, the diameter of the human retina that can be focused and imaged is only about 0.35 mm. There is a substance called lutein in the macula with a diameter of 1.5 to 2 mm. The role of lutein is to block blue light and protect the retina, thereby protecting eyesight. If excessive blue light is irradiated, the macula will be damaged and cause age-related macular degeneration.

Another lecture pointed out that the lifespan of the human eyeball is about 50 years. From the age of 40, the lens begins to turn yellow and can automatically block blue light. Therefore, after the age of 40, there are more cases of cataracts in the lens. On the contrary, young people's crystals are clear and have poor ability to block blue light, which may be seriously affected by blue light.

Let’s talk about the influence of blue light on clock functions. Blue light is originally an indispensable light for human beings. The sun contains more blue light. Every day the sun rises and illuminates the blue light, which makes humans wake up and start to move. When the sun sinks, the blue light disappears, and the melatonin in the human body decreases, which induces humans to sleep.

But in recent years, with the popularization of electronic products equipped with LED backlights and LED lighting, human eyes are exposed to blue light day and night. This may disrupt the rhythm of life (circadian rhythm) based on human body functions.

Professor Tsubota of Keio University in Japan pointed out: "Recently, researchers have discovered a group of cells called the'third visual cell' that has absorption peaks at blue wavelengths, and found that this cell controls the circadian rhythm." The body absorbs a lot during the day. There is no problem with blue light, but it won't work if you continue to expose blue light at night. If you continue to look at the blue light at night, "the body will mistakenly think that it is still daytime."

It takes a long time to verify the mid- to long-term effects of blue light, and now users of electronic products have begun to wear anti-blue glasses. Professor Sliney of Johns Hopkins University in the United States pointed out at the society: "Although wearing anti-blue glasses is not a mandatory requirement at present, there is no reason to deny users that they should be equipped with anti-blue glasses for the sake of insurance."

LED researchers’ speeches are also thought-provoking. Hunt, a professor at the University of California, pointed out that if the luminous efficiency of white LEDs has been increased in the current way, the brightness of the blue part will inevitably be increased. LED manufacturers said that as a technology to solve this problem, they are developing LEDs with a spectrum close to sunlight.