ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 EL for Broadband Optical Radiation Karl Schulmeister ICNIRP SC-IV Member Seibersdorf Laboratories, Austria Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 100 nm ~400 nm 780 nm 1 mm UV vis IR Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Exposure Limits •UV –s() • UV-A • Retina photochemical • Retina thermal •Infraredeye • Skin (vis. and IR) Photographs courtesy of P Söderberg JP Cesarini and Univ. Michigan, Kellogg Eye Center Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Exposure Limits •UV –s() • UV-A • Retina photochemical • Retina thermal • Infrared eye • Skin (vis. and IR) Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Current Guidelines: ICNIRP Guidelines on limits of exposure to broad-band incoherent optical radiation (0.38-3µm) Health Phys. 73: 539-554; 1997 New Edition of Guidelines for visible and IR: Open Consultation 2011 Health Physics Publication: End 2012/Beginning 2013 Product Standards updated in parallel: CIES009/ IEC 62471 (Lamp Product Safety Standard) IEC 60825-1 (Laser Product Safety Standard) Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Absorption location and mechanism overview •UV-C, B •UV-A P H O T O- •vis C H E M I C A L E = h * •IR-A •IR-B, C T H E R M A L Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Changes in Guidelines . Thermally induced retinal injury . Near IR limit for cornea/lens No changes: .photochemically induced retinal injury „blue light hazard“ (but averaging FOV defined for t > 100 s) .UV .skin Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Current EL - retinal thermal injury Effective Exposure Exposure Limit 10.25 2 1 L RtkWmsr() 50 in rad! For t < 10 s – Wavelength dependence – Base limit value – Retinal spot size dependence – Pulse duration dependence Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 R() Wavelength Dependence 10 Thermal Current 1 0.1 Thermal New 0.01 Action Spectrum (rel.) Spectrum Action 400 600 800 1000 1200 1400 Lund DJ, BE Stuck, P Edsall Wavelength (nm) Retinal injury thresholds for blue wavelength lasers Health Phys 90: 477-484; 2006 Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 R() Wavelength Dependence 10 1.0 Thermal Current 1 0.5 0.1 Relative injury threshold Relative injury 400 500 600 700 Wavelength [nm] Thermal New 0.01 Action Spectrum (rel.) Spectrum Action 400 600 800 1000 1200 1400 Lund DJ, BE Stuck, P Edsall Wavelength (nm) Retinal injury thresholds for blue wavelength lasers Health Phys 90: 477-484; 2006 Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 ] Sun -1 105 weighted, current nm -1 sr -2 Unweighted 104 103 weighted, new Spectral Radiance [W m Spectral Radiance [W 102 400 600 800 1000 1200 Wavelength [nm] Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 ] Sun -1 105 weighted, current nm -1 sr -2 Unweighted 104 103 weighted, new 7 W m-2 sr-1 eff. Spectral Radiance [W m Spectral Radiance [W 102 400 600 800 1000 1200 Wavelength [nm] Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 ] Sun -1 105 weighted, current nm -1 -2 -1 sr 16 W m sr eff. -2 Unweighted 104 103 weighted, new 7 W m-2 sr-1 eff. Spectral Radiance [W m Spectral Radiance [W 102 400 600 800 1000 1200 Wavelength [nm] Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop WavelengthEdinburgh, Evaluation United Kingdom, 9-11 Less May 2012 Restrictive 3.5 3.0 2.5 2.0 1.5 Old/New Effective Radiance 1.0 1000 2000 3000 4000 5000 6000 7000 Broadband OpticalW Radiationarm White Colour Temperature [Kelvin] Cold White Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Current EL - retinal thermal injury Radiance Effective Exposure Exposure Limit 10.25 2 1 L RtkWmsr() 50 in rad! For t < 10 s – Wavelength dependence – Base limit value – Retinal spot size dependence – Pulse duration dependence Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Angular Subtense of Source & Image Diameter []rad Distance Sun: = 0.01 rad Image: 170 µm Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Solid Angle of Source & Image Area []sr Distance2 []sr 2 4 Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 W Irradiance W m2 Radiance 2 m sr Solid Angle[] sr W/m2 Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 WW Ret.Irrad.Tsr Radiance Solid Angle Pupil[ ] 22 mmsr W/m2 Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Properties of Radiance . Does not depend on distance Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 W Irradiance W m2 Radiance 2 m sr Solid Angle[] sr W/m2 Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Properties of Radiance . Is not changed by optical intruments Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Telescope: 7 Magn. Image: 1.2 mm 50 mm Optics Diam. 72 x Irr. x Same ret. irradiance! Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Spot Size Dependence Retinal diameter [µm] 110100 ] -2 -2 a) 1000 d e p . 100 d e min p en max de nc 10 e no dep. Retinal radiant exposure [units: J m 110100 [mrad] Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Retinal diameter [µm] Retinal diamete r [µm] 110100 1 10 100 100 . p b) e -2 a) d 2 1000 d ] e p 10 -2 . ce 100 n 1 de d min e max n min p max [units: µJ] [units: e e p m [units: J n e d de n ce no dep. 10 no dep. 0,1 Retinal radiant exposure Total Intraocular Energy 110100 1 10 100 [mrad] [mrad] Radiance = Retinal Irradiance Solid Angle of Pupil Retinal Irradiance = IOP/Image Area Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Larger Spot: Compromised Cooling 50 100 ms 1000 µm Temperature rise 100 µm 40 after 100 ms 30 20 10 Temperature difference [K] difference Temperature 0 -1000 -800 -600 -400 -200 0 200 400 600 800 1000 Radius [µm] For same retinal irradiance, larger spot higher temperature Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Larger Spot: Compromised Cooling 50 100 ms 1000 µm Temperature rise 100 µm 40 after 100 ms 30 Injury when critical temperature is exceeded →→ LargerLarger spotsspots havehave lowerlower20 injuryinjury thresholdthreshold 10 Temperature difference [K] difference Temperature 0 -1000 -800 -600 -400 -200 0 200 400 600 800 1000 Radius [µm] For same retinal irradiance, larger spot higher temperature Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Spot Size Dependence Retinal diameter [µm] 110100 ] -2 -2 a) 1000 d e p . 100 d e min p en max de Current: nc 10 e no dep. max = 100 mrad 1.7 mm @ retina Retinal radiant exposure [units: J m 110100 [mrad] Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Spot Size Study . 532 nm (green), 1090 nm (IR) . Pulse durations 100 µs to 2 s . Spot Size: 20 µm to 2 mm 532 nm: 31 thresholds 170 samples 5000 exposures Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Spot Size Dependence 1000 ] -2 100 ] -2 2 s 1000 -2 655 ms dep. 10 100 ms 100 min max 10 ms 10 dependence no dep. Retina radiantexposurem J [units: 1 1 ms Radiant Exposure [J cm 110100 [mrad] 0.1 ms Diffusion length = 2 √(Dth t) 0,1 10 100 1000 Diameter [µm] Ex-vivo and computer model study on retinal thermal laser induced damage in the visible wavelength range K Schulmeister, et al J. Biomed. Optics 13, 054038 (2008) Broadband Optical Radiation Karl Schulmeister ICNIRP 7th International NIR Workshop Edinburgh, United Kingdom, 9-11 May 2012 Impact of radial cooling 50 45 100 ms pulse duration 40 35 30 25 D = 1.6 mm 20 D = 400 µm 15 D = 200 µm D = 1.0 mm 10 D = 800 µm D = 100 µm Temperature rise [K] 5 0 -2000 -1000 0 1000 2000 Radius [µm] Broadband Optical Radiation Karl