IEC 62471 Photobiological Safety Certification

In accordance with the international standard IEC 62471, optical radiation affecting the eyes and skin covers the wavelength range of 200–3000 nm. Based on varying hazard levels, the photobiological radiation safety of non-laser products such as LEDs is classified into four categories.

①　Exempt Group (No Hazard)

No photobiological radiation hazard is posed even under the limit conditions specified in this standard.

②　Category Ⅰ (Low Hazard)

No photobiological radiation hazard occurs under normal usage conditions and in line with normal human light exposure behavior.

③　Category Ⅱ (Moderate Hazard)

No photobiological radiation hazard occurs due to human eye aversion to glare from high-brightness light sources or discomfort responses to thermal radiation.

④　Category Ⅲ (High Hazard)

Radiation hazards are caused even by instantaneous light exposure.

Currently, the photobiological radiation safety of LED products for general lighting mainly focuses on retinal blue-light photocheMICal damage. LED products for non-general lighting applications may also involve ULtraviolet and infraRED radiation.

Key Points Analysis of IEC/TR 62478 Blue-Light Hazard Assessment

Introduction to IEC/TR 62478:2014

IEC 62471 is a comprehensive standard covering all potential health hazards from artificial optical radiators, including ultraviolet, visible, and infrared spectra. Within this standard, the spectrum that may cause potential retinal hazards mainly originates from the blue-light portion of the visible spectrum.

As recognized by Golden Testing Laboratory, the allowable maximum exposure time  depends on the light source product itself and the observation distance. For general lighting luminaires, the assessment distance is typically set at the position where illuminance is 500 lx, and shall not be less than 200 mm. This takes into account that illuminance values often vary in practical applications.

Besides specifying that its measurement conditions differ from those of IEC 62471, IEC/TR 62478 mainly addresses the following two issues:

1. The transfer of photobiological safety information from light source components to higher-level lighting products based on such components.

2. Recommendations on exposure distance and hazard classification. These recommendations are provided based on blue-light hazard value analysis through spectral calculations and optical considerations.

Spectrum, Correlated Color Temperature and Blue-Light Hazard

Spectral measurement for exposure limit calculations.

Implementation Rules of IEC 62478:2014

On the basis of IEC 62471, IEC 62478 emphasizes the transfer of blue-light hazard information from light sources to luminaires. IEC 62478 mainly measures light sources, but can also directly measure luminaires, and redefines three safety levels: RG0 unlimited, RG1 unlimited, and Ethr for RG2.

1. “Ethr for RG2”

Applies where the blue-light hazard-weighted radiance may exceed the RG1 limit, or where radiance cannot be measured.

Ethr is the illuminance value at the boundary between RG1 and RG2, used to determine the minimum safe operating distance . The installation and operating distance of the luminaire should generally be greater than .

Requirements and Testing Introduction of IEC/EN 62471 Standard

IEC/EN 62471 mainly measures broadband optical radiation and performs calculations by integrating factors such as the response time, angle, and sensitivity of human eyes and skin to light.

Applicable Products

Applicable to ultraviolet germicidal and disinfection products, as well as various light sources, modules, luminaires, pulsed/flickering luminaires, and electrical appliances. It covers measurements of parameters including spectral distribution, spectral radiance, spectral irradiance, effective ultraviolet radiation ratio (mW/klm), and assessment of optical radiation hazard levels.

Test Wavelength Range

Optical radiation testing covers the wavelength range of 200 nm to 3000 nm.

Test Parameters

1. Irradiance (radiant flux per unit area, unit: W·m⁻²)

2. Radiance (irradiance per field of view, convertible from irradiance)

Test Objects

1. Ultraviolet hazards to the skin and eyes

2. Near-ultraviolet hazards to the eyes (315 nm–400 nm)

3. Retinal blue-light hazard

4. Retinal blue-light hazard (small light sources)

5. Retinal thermal hazard

6. Retinal thermal hazard (for faint visual stimuli) (780 nm–1400 nm)

7. Infrared radiation hazard to the eyes (780 nm–3000 nm)

8. Thermal hazard to the skin (380 nm–3000 nm)