Blue Light Hazard
B(λ)-weighted irradiance of a laser beam at 300–700 nm, the longest exposure within the ICNIRP blue-light limit, and the IEC 62471 risk group.
Educational only — not compliance-grade
These pages implement the published exposure limits for the cases each one states, but they are educational tools: no laser safety officer has signed them off.
- Do not use these results alone for PPE selection, NHZ / NOHD approval, controlled-area sign-off, enclosure/interlock approval, or formal classification.
- Always verify against ANSI Z136.1, IEC 60825-1, your local procedures, and the responsible laser safety officer / CLSO.
Formulas
E = P / (π(d/2)²) (corneal irradiance)
EB = Σ Eλ × B(λ) × Δλ = E × B(λ) (single wavelength)
B(λ): ICNIRP 2013 Table 2; 10(450−λ)/50 for 500–600 nm, 0.001 for 600–700 nm
Small source (α < 11 mrad): EB·t ≤ 100 J/m² (0.25–100 s), EB ≤ 1 W/m² (t ≥ 100 s)
Risk group (IEC 62471 Table 6.1, small source): Exempt ≤ 1 W/m², RG2 ≤ 400 W/m², RG3 above
Input
Results
Corneal Irradiance
31.8 W/cm²
B(λ) Weight
0.940
Blue-weighted E_B
2.99e+5 W/m²
Max Exposure
3.34e-4 s
Risk Group
RG3 (High Risk)
Below 0.25 s the retinal thermal limit governs, which this page doesn't evaluate.
Blue Light Hazard Function B(λ)
Model and references
Exact. The equations are exact within the stated assumptions, or are a standard's tabulated values. The results are as good as the inputs. About the tiers
Tabulated B(λ), small-source limits and IEC risk groups for a monochromatic beam; irradiance is the beam power over the 1/e² circle. Not modelled: extended sources, pulses and broadband spectra.
- ICNIRP (2013). Guidelines on limits of exposure to incoherent visible and infrared radiation. Health Phys. 105(1), 74–96. Table 2 (B(λ)) and eqns 15–17 (small-source limits). doi:10.1097/hp.0b013e318289a611
- IEC 62471:2006. Table 4.2 (B(λ) for 500–600 nm) and Table 6.1 (risk groups, small source).