Recently, "LED bio-safety" or "LED blue-light hazard", like tainted milk powder and plasticizer, has been widely concerned by the public and the media, and even some representatives and CPPCC members have proposed to solve the "LED Blu-ray hazard". Before, the application and promotion of LED products should be stopped. The problem has been heated up. Many leaders of the National Standards Committee are also very concerned about this issue. The author borrows the opportunity of the media to review the ins and outs of LED light biosafety. I hope that everyone can rationally look at the "LED light biosafety" and "LED blue light hazard" issues, and hope that everyone can rest assured that the use of quality LEDs product.
I. The process and historical background of the relevant standards for “photobiosafety”
The issue of “photobiosafety” began to receive attention, beginning with the International Commissioning Non-Ionizing Radiation Protection (ICNIRP), which was registered in Germany at the end of the last century. A micro-international organization with less than 20 members, mainly Europeans and Americans. The guidelines for limiting exposure to light and radiation acceptable to the human eye and skin were proposed as the main basis. Also, under the impetus of several active members of ICNIRP, the International Commission on Illumination and Photochemical and Photochemical Division (CIED6) was established. CIETC6-47 Technical Committee, which issued the CIES009/E:2002 International Standard for Light Biosafety of Lamps and Lamp Systems in 2002. Due to the authority of the International Electrotechnical Commission (IEC) in product standardization, CIETC6-47 In the following years, 3 to 4 core members actively recommended the CIES009/E:2002 standard to IECTC34, the most authoritative standardization organization of the standard consumer industry in the standard. Unfortunately, due to the existence of the CIES009/E:2002 standard The definition of limits is too complicated and the evaluation methods are not scientific and clear, and so on. IECTC34 in 2005 The proposal “This standard has also become an IEC standard” was rejected. After the IECTC34 was rejected, the relevant members did not adopt the method of modifying the standard. Instead, in 2005, under the leadership of experts with laser technology background, they began to move to IECTC76. “Optical Radiation Safety and Laser Equipment.” Since the name of IECTC76 has the word “light radiation safety”, IECTC76 has never paid attention to non-laser (incoherent light) matters, so it did not exist in IECTC76 at that time. CIES009/E: Stakeholders of the 2002 standard, and there are not enough relevant expert resources. Soon, in 2006, the CIES009/E:2002 standard was accepted as the equivalent standard by IECTC76 and numbered according to IEC62471:2006 standard. Released to the world. Due to the authority of the IEC, and it is published by IECTC76's WG9 “Incoherent Light Source (Non-Laser Source)” standard working group, theoretically all products involving “non-laser source” are affected by the standard. It’s conceivable that it has brought a lot of confusion to many “non-laser” light-related industries and the general public, even difficult to happen.
Second, the origin of "LED blue light hazard"
In fact, the developers of CIES009:2002/IEC62471:2006 international standards, the main object of concern in the industry when the standards are formulated is not LEDs (then the power of LEDs is still small, white LEDs are not common), the main task at that time It is to limit the ultraviolet radiation of fluorescent lamps. The reason for limiting the ultraviolet radiation is correct. The reason is that the principle of the fluorescent lamp is that the strong ultraviolet light in the C-band excites the phosphor, and the phosphor is white light by the excitation light. If the lamp glass has insufficient ability to block the ultraviolet radiation, then the leaked ultraviolet light is sure. It can cause damage to the human eye and skin. Since the ultraviolet rays are not visible to the human eye, this hazard is more serious once it exists.
With the rapid development of high-power LED technology, Mr. Nakamura invented the blue-light-excited yellow-light phosphor and achieved great success through the blue-yellow light-mixing white light technology route. LEDs are rapidly applied in various lighting and lighting industries beyond the speed expected by people. .
It is very natural for the LED protagonist to appear on the scene. However, the white light emitted by the LED has neither infrared rays nor ultraviolet rays. The white light emitted is all within the visible range of the human eye. From the luminous band, the LED white light is calculated. It is a kind of white light that is relatively "pure" in the white light source invented by human beings. To find "hazard" from such white LEDs, it is completely understandable to go from the "blue light" that white LED technology cannot bypass.
CIES009:2002/IEC62471:2006 international standard has a section on "Retinal blue light hazard exposure limit", this chapter lists the human eye blue hazard weighting function, function data shows that in the 400nm ~ 500nm blue light band, the human eye is indeed It is vulnerable to blue light. Since the peak wavelength of the blue light emitted by the LED is between 460 nm and 470 nm, which falls just in this sensitive band, the LED white light is referred to as "blue light hazard". This should be the main source of the "LED Blu-ray Hazard" theory.
In fact, fluorescent lamps inevitably emit mercury lines, in which the 436 nm strong line spectrum radiation falls in the blue light band, and the line falls exactly at the peak of the CIES009:2002/IEC62471:2006 international standard human eye blue light hazard weighting function. On the point! In contrast, the blue light hazard of LEDs is only about 70%.
