Radiation is divided into ionizing radiation and non-ionizing radiation, where ionizing radiation refers to radiation that has sufficiently high energy to ionize atoms, such as X, α, β, and γ rays. Non-ionizing radiation energy is weaker than ionizing radiation, and non-ionizing radiation does not ionize matter. The electromagnetic radiation generated by the luminaire is non-ionizing radiation.
The key elements of the electromagnetic radiation impact and evaluation of the lighting equipment include three aspects: the working frequency of the product to be evaluated, the limit of the electromagnetic radiation that the human body can accept, and the measurement and evaluation methods of the influence of the lighting equipment on the human body.
Lighting devices with different light sources have their own frequency ranges, such as LEDs operating under DC and their lamps, tungsten lamps operating at power frequency (50 Hz), and various gas discharge lamps using magnetic ballasts, as well as high frequency ( Gas discharge lamps operating above 20 kHz).
After nearly 25 years of research, based on more than 1,000 articles and 144 reference books, in 2005, the Institute of Electrical and Electronics Engineers (IEEE) published IEEE C95.1:2005 Exposure to radio frequency electromagnetic fields from 3 kHz to 300 GHz for human safety levels. On the basis of a certain safety factor, according to the side effects on human health, the standard gives the general public population a basic limit (BF) for prescribed exposure, and the person under this condition is safe. However, the standard also proposes that exceeding the BF does not necessarily mean that it is unsafe because the given limits introduce a more conservative safety factor.
Based on the sensitivity of different human tissues or parts to the relevant frequency electromagnetic radiation, IEEE C95.1:2005 gives the corresponding basic restrictions.
IEEE C95.1:2005 states that for near-field or re-radiating objects, the field strength in the near-field due to the electric field strength (in V/m) may be high, and as the distance increases, the absorption decreases rapidly, resulting in absorption only It is very small, and the electromagnetic field energy distribution in the near field is very complicated, so the current intensity (mA/m2) is better measured in the near field, and the degree of compliance with the standard can be more realistically determined.
1. Basic ideas of IEC standards
IEC 62493:2009 is applicable to the assessment of human exposure to electromagnetic radiation from lighting equipment. The evaluation included an induced current density between 20 kHz and 10 MHz and a specific absorption rate (SAR) between 100 kHz and 300 MHz around the illumination device.
Since the design frequency of the high-frequency operation of the electronic control device in the lighting appliance is 20 kHz or more, and the operating frequency of the electrodeless lamp is between 2.51 MHz and 3 MHz, the applicable frequency of the standard covers various types of lighting electrical products.
2. Measurement principle of IEC standard
According to the research results, the influence of electromagnetic radiation on the human body is mainly reflected in the induced current density and thermal effect of human tissues. The current density generated by the electric field (weight 0.85) is measured in accordance with IEC 62493:2009. The current density (weight 0.15) and thermal effect generated by the magnetic field are measured in accordance with CISPR 15.
IEC 62311:2007 "Evaluation of limits for human body electromagnetic radiation (0Hz-300GHz) for electronic and electrical equipment" A digital model of a homogeneous human body (shown in Figure 1) shows that the human body has a head diameter of 210 mm and a neck diameter of 110mm.
It is generally believed that the head of the mannequin is closest to the lighting device, and the maximum current density appears in the neck of the human body. The head of a human body model is used as a sensing part of the human body to measure the induced current, and the diameter of the neck of the human body is used. Calculate the induced current density. IEC 62493 uses the head diameter and neck diameter of a homogeneous human body as proposed in IEC 62311, as shown in Figure 2.
Figure 2 shows the diameter of the conductive ball used as the measuring device and the diameter of the neck used for the calculation.
The measuring device for the induced current density is shown in FIG.
Figure 3 measuring device
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